1
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Chanduri M, Kumar A, Weiss D, Emuna N, Barsukov I, Shi M, Tanaka K, Wang X, Datye A, Kanyo J, Collin F, Lam T, Schwarz UD, Bai S, Nottoli T, Goult BT, Humphrey JD, Schwartz MA. Cellular stiffness sensing through talin 1 in tissue mechanical homeostasis. SCIENCE ADVANCES 2024; 10:eadi6286. [PMID: 39167642 PMCID: PMC11338229 DOI: 10.1126/sciadv.adi6286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 07/16/2024] [Indexed: 08/23/2024]
Abstract
Tissue mechanical properties are determined mainly by the extracellular matrix (ECM) and actively maintained by resident cells. Despite its broad importance to biology and medicine, tissue mechanical homeostasis remains poorly understood. To explore cell-mediated control of tissue stiffness, we developed mutations in the mechanosensitive protein talin 1 to alter cellular sensing of ECM. Mutation of a mechanosensitive site between talin 1 rod-domain helix bundles R1 and R2 increased cell spreading and tension exertion on compliant substrates. These mutations promote binding of the ARP2/3 complex subunit ARPC5L, which mediates the change in substrate stiffness sensing. Ascending aortas from mice bearing these mutations showed less fibrillar collagen, reduced axial stiffness, and lower rupture pressure. Together, these results demonstrate that cellular stiffness sensing contributes to ECM mechanics, directly supporting the mechanical homeostasis hypothesis and identifying a mechanosensitive interaction within talin that contributes to this mechanism.
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Affiliation(s)
- Manasa Chanduri
- Yale Cardiovascular Research Center, Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, Yale University, New Haven, CT 06511, USA
| | - Abhishek Kumar
- Yale Cardiovascular Research Center, Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, Yale University, New Haven, CT 06511, USA
| | - Dar Weiss
- Department of Biomedical Engineering, Yale University, New Haven, CT 06510, USA
| | - Nir Emuna
- Department of Biomedical Engineering, Yale University, New Haven, CT 06510, USA
| | - Igor Barsukov
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - Miusi Shi
- Yale Cardiovascular Research Center, Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, Yale University, New Haven, CT 06511, USA
| | - Keiichiro Tanaka
- Yale Cardiovascular Research Center, Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, Yale University, New Haven, CT 06511, USA
| | - Xinzhe Wang
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06511, USA
| | - Amit Datye
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06511, USA
| | - Jean Kanyo
- Keck MS & Proteomics Resource, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Florine Collin
- Keck MS & Proteomics Resource, Yale University School of Medicine, New Haven, CT 06510, USA
| | - TuKiet Lam
- Keck MS & Proteomics Resource, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Udo D. Schwarz
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06511, USA
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06510, USA
| | - Suxia Bai
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Timothy Nottoli
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Benjamin T Goult
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
- School of Biosciences, University of Kent, Canterbury, UK
| | - Jay D. Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT 06510, USA
| | - Martin A. Schwartz
- Yale Cardiovascular Research Center, Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, Yale University, New Haven, CT 06511, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT 06510, USA
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06511, USA
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2
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Cavinato C, Spronck B, Caulk AW, Murtada SI, Humphrey JD. AT1b receptors contribute to regional disparities in angiotensin II mediated aortic remodelling in mice. J R Soc Interface 2024; 21:20240110. [PMID: 39192727 PMCID: PMC11350382 DOI: 10.1098/rsif.2024.0110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 06/21/2024] [Accepted: 07/26/2024] [Indexed: 08/29/2024] Open
Abstract
The renin-angiotensin system plays a key role in regulating blood pressure, which has motivated many investigations of associated mouse models of hypertensive arterial remodelling. Such studies typically focus on histological and cell biological changes, not wall mechanics. This study explores tissue-level ramifications of chronic angiotensin II infusion in wild-type (WT) and type 1b angiotensin II (AngII) receptor null (Agtr1b -/-) mice. Biaxial biomechanical and immunohistological changes were quantified and compared in the thoracic and abdominal aorta in these mice following 14 and 28 days of angiotensin II infusion. Preliminary results showed that changes were largely independent of sex. Associated thickening and stiffening of the aortic wall in male mice differed significantly between thoracic and abdominal regions and between genotypes. Notwithstanding multiple biomechanical changes in both WT and Agtr1b -/- mice, AngII infusion caused distinctive wall thickening and inflammation in the descending thoracic aorta of WT, but not Agtr1b -/-, mice. Our study underscores the importance of exploring differential roles of receptor-dependent angiotensin II signalling along the aorta and its influence on distinct cell types involved in regional histomechanical remodelling. Disrupting the AT1b receptor primarily affected inflammatory cell responses and smooth muscle contractility, suggesting potential therapeutic targets.
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Affiliation(s)
- Cristina Cavinato
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
- LMGC, Univ. Montpellier, CNRS, Montpellier, France
| | - Bart Spronck
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Alexander W. Caulk
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Sae-Il Murtada
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Jay D. Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA
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3
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Ramachandra AB, Jiang B, Jennings IR, Manning EP, Humphrey JD. Remodeling of Murine Branch Pulmonary Arteries Under Chronic Hypoxia and Short-Term Normoxic Recovery. J Biomech Eng 2024; 146:084501. [PMID: 38421341 DOI: 10.1115/1.4064967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 02/05/2024] [Indexed: 03/02/2024]
Abstract
Chronic hypoxia plays a central role in diverse pulmonary pathologies, but its effects on longitudinal changes in the biomechanical behavior of proximal pulmonary arteries remain poorly understood. Similarly, effects of normoxic recovery have not been well studied. Here, we report hypoxia-induced changes in composition, vasoactivity, and passive biaxial mechanics in the main branch pulmonary artery of male C57BL/6J mice exposed to 10% FiO2 for 1, 2, or 3 weeks. We observed significant changes in extracellular matrix, and consequently wall mechanics, as early as 1 week of hypoxia. While circumferential stress and stiffness returned toward normal values by 2-3 weeks of hypoxia, area fractions of cytoplasm and thin collagen fibers did not return toward normal until after 1 week of normoxic recovery. By contrast, elastic energy storage and overall distensibility remained reduced after 3 weeks of hypoxia as well as following 1 week of normoxic recovery. While smooth muscle and endothelial cell responses were attenuated under hypoxia, smooth muscle but not endothelial cell responses recovered following 1 week of subsequent normoxia. Collectively, these data suggest that homeostatic processes were unable to preserve or restore overall function, at least over a brief period of normoxic recovery. Longitudinal changes are critical in understanding large pulmonary artery remodeling under hypoxia, and its reversal, and will inform predictive models of vascular adaptation.
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Affiliation(s)
| | - Bo Jiang
- Department of Surgery, Yale School of Medicine, New Haven, CT 06520
| | - Isabella R Jennings
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520
- Yale University
| | - Edward P Manning
- Section of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06520;West Haven Connecticut VA and Pulmonary and Critical Care Medicine, VA Connecticut Healthcare System, West Haven, CT 06516
| | - Jay D Humphrey
- Department of Biomedical Engineering and Vascular Biology and Therapeutics Program, Yale University, New Haven, CT 06520
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4
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Matz J, Gonzalez MP, Niedbalski P, Kim H, Chen Y, Sebastiani P, Gollner MJ, Bellini C, Oakes JM. Assessment of Left Lung Remodeling With Magnetic Resonance Imaging in a Murine Model Following Exposure to Douglas Fir Smoke. J Biomech Eng 2024; 146:071010. [PMID: 38581378 PMCID: PMC11080952 DOI: 10.1115/1.4065272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 04/03/2024] [Accepted: 04/03/2024] [Indexed: 04/08/2024]
Abstract
Wildland firefighters (WLFFs) experience lung function decline due to occupational exposure to fire smoke. WLFFs typically do not wear respiratory personal protective equipment, and if they do, it is a simple bandana, which is not effective at filtering smoke. To pinpoint the biological underpinnings of abnormal respiratory function following 3-7 years of WLFF service, we exposed mice to Douglas fir smoke (DFS) over 8 weeks. Following exposure, we assessed changes in lung structure through Magnetic Resonance Imaging (MRI) and histological analysis, which was supported by immunohistochemistry staining. With MRI, we found that the signal decay time, T2*, from ultrashort echo time (UTE) images was significantly shorter in mice exposed to DFS compared to air controls. In addition, the variation in T2* was more heterogeneously distributed throughout the left lung in DFS-exposed mice, compared to air controls. As confirmed by histological analysis, shorter T2* was caused by larger parenchyma airspace sizes and not fibrotic remodeling. Destruction of the alveolar spaces was likely due to inflammation, as measured by an influx of CD68+ macrophages and destruction due to enhanced neutrophil elastase. In addition, measurements of airspace dimensions from histology were more heterogeneously distributed throughout the lung, corroborating the enhanced relative dispersion of T2*. Findings from this study suggest that the decline in lung function observed in WLFFs may be due to emphysema-like changes in the lung, which can be quantified with MRI.
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Affiliation(s)
- Jacqueline Matz
- Department of Bioengineering, Northeastern University, Boston, MA 02115
- Northeastern University
| | | | - Peter Niedbalski
- Pulmonary, Critical Care and Sleep Medicine, Kansas University Medical Center, Boston, MA 02115
- University of Kansas
| | - Hannah Kim
- Department of Bioengineering, Northeastern University, Boston, MA 02115
- Northeastern University
| | - Ye Chen
- Tufts Clinical and Translational Science Institute (CTSI), Tufts Medical Center, Boston, MA 02115
- Tufts Medical Center
| | - Paola Sebastiani
- Institute for Clinical Research and Health Policy Studies (ICRHPS), Tufts Medical Center and Tufts University School of Medicine, Boston, MA 02115
- Tufts Medical Center
| | - Michael J. Gollner
- Department of Mechanical Engineering, University of California Berkeley, Berkeley, CA 94720
- University of California, Berkeley
| | - Chiara Bellini
- Department of Bioengineering, Northeastern University, Boston, MA 02115
| | - Jessica M. Oakes
- Department of Bioengineering, Northeastern University, 360 Huntington Ave, Boston, MA 02115
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5
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Vargas AI, Tarraf SA, Jennings T, Bellini C, Amini R. Vascular Remodeling During Late-Gestation Pregnancy: An In-Vitro Assessment of the Murine Ascending Thoracic Aorta. J Biomech Eng 2024; 146:071004. [PMID: 38345599 DOI: 10.1115/1.4064744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Indexed: 03/20/2024]
Abstract
Maternal mortality due to cardiovascular disease is a rising concern in the U.S. Pregnancy triggers changes in the circulatory system, potentially influencing the structure of the central vasculature. Evidence suggests a link between a woman's pregnancy history and future cardiovascular health, but our understanding remains limited. To fill this gap, we examined the passive mechanics of the murine ascending thoracic aorta during late gestation. By performing biaxial mechanical testing on the ascending aorta, we were able to characterize the mechanical properties of both control and late-gestation tissues. By examining mechanical, structural, and geometric properties, we confirmed that remodeling of the aortic wall occurred. Morphological and mechanical properties of the tissue indicated an outward expansion of the tissue, as reflected in changes in wall thickness (∼12% increase) and luminal diameter (∼6% increase) at its physiologically loaded state in the pregnant group. With these geometric adaptations and despite increased hemodynamic loads, pregnancy did not induce significant changes in the tensile wall stress at the similar physiological pressure levels of the pregnant and control tissues. The alterations also included reduced intrinsic stiffness in the circumferential direction (∼18%) and reduced structural stiffness (∼26%) in the pregnant group. The observed vascular remodeling maintained the elastic stored energy of the aortic wall under systolic loads, indicating preservation of vascular function. Data from our study of pregnancy-related vascular remodeling will provide valuable insights for future investigations of maternal cardiovascular health.
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Affiliation(s)
- Ana I Vargas
- Department of Bioengineering, Northeastern University, Boston, MA 02115
| | - Samar A Tarraf
- Department of Bioengineering, Northeastern University, Boston, MA 02115
- Northeastern University
| | - Turner Jennings
- Department of Mechanical and Industrial Engineering, Department of Bioengineering, Northeastern University, Boston, MA 02115
- Northeastern University
| | - Chiara Bellini
- Department of Bioengineering, Northeastern University, Boston, MA 02115
| | - Rouzbeh Amini
- Department of Mechanical and Industrial Engineering, Department of Bioengineering, Northeastern University, Boston, MA 02115
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6
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Manning EP, Mishall P, Ramachandra AB, Hassab AHM, Lamy J, Peters DC, Murphy TE, Heerdt P, Singh I, Downie S, Choudhary G, Tellides G, Humphrey JD. Stiffening of the human proximal pulmonary artery with increasing age. Physiol Rep 2024; 12:e16090. [PMID: 38884325 PMCID: PMC11181131 DOI: 10.14814/phy2.16090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/16/2024] [Accepted: 05/16/2024] [Indexed: 06/18/2024] Open
Abstract
Adverse effects of large artery stiffening are well established in the systemic circulation; stiffening of the proximal pulmonary artery (PPA) and its sequelae are poorly understood. We combined in vivo (n = 6) with ex vivo data from cadavers (n = 8) and organ donors (n = 13), ages 18 to 89, to assess whether aging of the PPA associates with changes in distensibility, biaxial wall strain, wall thickness, vessel diameter, and wall composition. Aging exhibited significant negative associations with distensibility and cyclic biaxial strain of the PPA (p ≤ 0.05), with decreasing circumferential and axial strains of 20% and 7%, respectively, for every 10 years after 50. Distensibility associated directly with diffusion capacity of the lung (R2 = 0.71, p = 0.03). Axial strain associated with right ventricular ejection fraction (R2 = 0.76, p = 0.02). Aging positively associated with length of the PPA (p = 0.004) and increased luminal caliber (p = 0.05) but showed no significant association with mean wall thickness (1.19 mm, p = 0.61) and no significant differences in the proportions of mural elastin and collagen (p = 0.19) between younger (<50 years) and older (>50) ex vivo samples. We conclude that age-related stiffening of the PPA differs from that of the aorta; microstructural remodeling, rather than changes in overall geometry, may explain age-related stiffening.
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Affiliation(s)
- Edward P. Manning
- Section of Pulmonary, Critical Care, and Pulmonary MedicineYale School of MedicineNew HavenConnecticutUSA
- VA Connecticut Healthcare SystemWest HavenConnecticutUSA
| | - Priti Mishall
- Department of Anatomy and Structural BiologyAlbert Einstein College of MedicineBronxNew YorkUSA
- Department of Ophthalmology and Visual SciencesAlbert Einstein College of MedicineBronxNew YorkUSA
| | | | | | - Jerome Lamy
- Université Paris Cité, INSERM U970, PARCC, APHP Hôpital Européen Georges PompidouParisFrance
| | - Dana C. Peters
- Department of RadiologyYale School of MedicineNew HavenConnecticutUSA
| | - Terrence E. Murphy
- Department of Public Health SciencesThe Pennsylvania State University College of MedicineHersheyPennsylvaniaUSA
| | - Paul Heerdt
- Department of AnesthesiologyYale School of MedicineNew HavenConnecticutUSA
| | - Inderjit Singh
- Section of Pulmonary, Critical Care, and Pulmonary MedicineYale School of MedicineNew HavenConnecticutUSA
| | - Sherry Downie
- Department of Anatomy and Structural BiologyAlbert Einstein College of MedicineBronxNew YorkUSA
| | - Gaurav Choudhary
- Lifespan Cardiovascular Institute, Providence VA Medical CenterProvidenceRhode IslandUSA
- Warren Alpert Medical School, Brown UniversityProvidenceRhode IslandUSA
| | - George Tellides
- VA Connecticut Healthcare SystemWest HavenConnecticutUSA
- Department of Surgery (Cardiac)Yale School of MedicineNew HavenConnecticutUSA
| | - Jay D. Humphrey
- Department of Biomedical EngineeringYale UniversityNew HavenConnecticutUSA
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7
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Karbasion N, Xu Y, Snider JC, Bersi MR. Primary Mouse Aortic Smooth Muscle Cells Exhibit Region- and Sex-Dependent Biological Responses In Vitro. J Biomech Eng 2024; 146:060904. [PMID: 38421345 PMCID: PMC11005860 DOI: 10.1115/1.4064965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/02/2024]
Abstract
Despite advancements in elucidating biological mechanisms of cardiovascular remodeling, cardiovascular disease (CVD) remains the leading cause of death worldwide. When stratified by sex, clear differences in CVD prevalence and mortality between males and females emerge. Regional differences in phenotype and biological response of cardiovascular cells are important for localizing the initiation and progression of CVD. Thus, to better understand region and sex differences in CVD presentation, we have focused on characterizing in vitro behaviors of primary vascular smooth muscle cells (VSMCs) from the thoracic and abdominal aorta of male and female mice. VSMC contractility was assessed by traction force microscopy (TFM; single cell) and collagen gel contraction (collective) with and without stimulation by transforming growth factor-beta 1 (TGF-β1) and cell proliferation was assessed by a colorimetric metabolic assay (MTT). Gene expression and TFM analysis revealed region- and sex-dependent behaviors, whereas collagen gel contraction was consistent across sex and aortic region under baseline conditions. Thoracic VSMCs showed a sex-dependent sensitivity to TGF-β1-induced collagen gel contraction (female > male; p = 0.025) and a sex-dependent proliferative response (female > male; p < 0.001) that was not apparent in abdominal VSMCs. Although primary VSMCs exhibit intrinsic region and sex differences in biological responses that may be relevant for CVD presentation, several factors-such as inflammation and sex hormones-were not included in this study. Such factors should be included in future studies of in vitro mechanobiological responses relevant to CVD differences in males and females.
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Affiliation(s)
- Niyousha Karbasion
- Department of Mechanical Engineering & Materials Science, Washington University at St. Louis, St. Louis, MO 63130
| | - Yujun Xu
- Department of Mechanical Engineering & Materials Science, Washington University at St. Louis, St. Louis, MO 63130
- Washington University in St. Louis
| | - J. Caleb Snider
- Department of Mechanical Engineering & Materials Science, Washington University at St. Louis, St. Louis, MO 63130
- Washington University in St. Louis
| | - Matthew R. Bersi
- Department of Mechanical Engineering & Materials Science, Washington University at St. Louis, St. Louis, MO 63130
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8
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Szafron JM, Heng EE, Boyd J, Humphrey JD, Marsden AL. Hemodynamics and Wall Mechanics of Vascular Graft Failure. Arterioscler Thromb Vasc Biol 2024; 44:1065-1085. [PMID: 38572650 PMCID: PMC11043008 DOI: 10.1161/atvbaha.123.318239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 03/12/2024] [Indexed: 04/05/2024]
Abstract
Blood vessels are subjected to complex biomechanical loads, primarily from pressure-driven blood flow. Abnormal loading associated with vascular grafts, arising from altered hemodynamics or wall mechanics, can cause acute and progressive vascular failure and end-organ dysfunction. Perturbations to mechanobiological stimuli experienced by vascular cells contribute to remodeling of the vascular wall via activation of mechanosensitive signaling pathways and subsequent changes in gene expression and associated turnover of cells and extracellular matrix. In this review, we outline experimental and computational tools used to quantify metrics of biomechanical loading in vascular grafts and highlight those that show potential in predicting graft failure for diverse disease contexts. We include metrics derived from both fluid and solid mechanics that drive feedback loops between mechanobiological processes and changes in the biomechanical state that govern the natural history of vascular grafts. As illustrative examples, we consider application-specific coronary artery bypass grafts, peripheral vascular grafts, and tissue-engineered vascular grafts for congenital heart surgery as each of these involves unique circulatory environments, loading magnitudes, and graft materials.
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Affiliation(s)
- Jason M Szafron
- Departments of Pediatrics (J.M.S., A.L.M.), Stanford University, CA
| | - Elbert E Heng
- Cardiothoracic Surgery (E.E.H., J.B.), Stanford University, CA
| | - Jack Boyd
- Cardiothoracic Surgery (E.E.H., J.B.), Stanford University, CA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT (J.D.H.)
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9
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Ramachandra AB, Cavinato C, Humphrey JD. A Systematic Comparison of Normal Structure and Function of the Greater Thoracic Vessels. Ann Biomed Eng 2024; 52:958-966. [PMID: 38227167 DOI: 10.1007/s10439-023-03432-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 12/23/2023] [Indexed: 01/17/2024]
Abstract
The greater thoracic vessels are central to a well-functioning circulatory system and are often targeted in congenital heart surgeries, yet the structure and function of these vessels have not been well studied. Here we use consistent methods to quantify and compare microstructural features and biaxial biomechanical properties of the following six greater thoracic vessels in wild-type mice: ascending thoracic aorta, descending thoracic aorta, right subclavian artery, right pulmonary artery, thoracic inferior vena cava, and superior vena cava. Specifically, we determine volume fractions and orientations of the structurally significant wall constituents (i.e., collagen, elastin, and cell nuclei) using multiphoton imaging, and we quantify vasoactive responses and mechanobiologically relevant mechanical quantities (e.g., stress, stiffness) using computer-controlled biaxial mechanical testing. Similarities and differences across systemic, pulmonary, and venous circulations highlight underlying design principles of the vascular system. Results from this study represent another step towards understanding growth and remodeling of greater thoracic vessels in health, disease, and surgical interventions by providing baseline information essential for developing and validating predictive computational models.
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Affiliation(s)
- Abhay B Ramachandra
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520, USA.
- Department of Mechanical Engineering, Iowa State University, Ames, IA, USA.
| | - Cristina Cavinato
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520, USA
- Laboratoire de Mécanique et Génie Civile, Université Montpellier, Montpellier, France
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520, USA.
- Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA.
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10
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Hopper SE, Weiss D, Mikush N, Jiang B, Spronck B, Cavinato C, Humphrey JD, Figueroa CA. Central Artery Hemodynamics in Angiotensin II-Induced Hypertension and Effects of Anesthesia. Ann Biomed Eng 2024; 52:1051-1066. [PMID: 38383871 DOI: 10.1007/s10439-024-03440-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 12/30/2023] [Indexed: 02/23/2024]
Abstract
Systemic hypertension is a strong risk factor for cardiovascular, neurovascular, and renovascular diseases. Central artery stiffness is both an initiator and indicator of hypertension, thus revealing a critical relationship between the wall mechanics and hemodynamics. Mice have emerged as a critical animal model for studying effects of hypertension and much has been learned. Regardless of the specific mouse model, data on changes in cardiac function and hemodynamics are necessarily measured under anesthesia. Here, we present a new experimental-computational workflow to estimate awake cardiovascular conditions from anesthetized data, which was then used to quantify effects of chronic angiotensin II-induced hypertension relative to normotension in wild-type mice. We found that isoflurane anesthesia had a greater impact on depressing hemodynamics in angiotensin II-infused mice than in controls, which led to unexpected results when comparing anesthetized results between the two groups of mice. Through comparison of the awake simulations, however, in vivo relevant effects of angiotensin II-infusion on global and regional vascular structure, properties, and hemodynamics were found to be qualitatively consistent with expectations. Specifically, we found an increased in vivo vascular stiffness in the descending thoracic aorta and suprarenal abdominal aorta, leading to increases in pulse pressure in the distal aorta. These insights allow characterization of the impact of regionally varying vascular remodeling on hemodynamics and mouse-to-mouse variations due to induced hypertension.
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Affiliation(s)
- S E Hopper
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - D Weiss
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - N Mikush
- Translational Research Imaging Center, Yale School of Medicine, New Haven, CT, USA
| | - B Jiang
- Department of Thyroid and Vascular Surgery, 1st Hospital of China Medical University, Shen Yang, China
| | - B Spronck
- Department of Biomedical Engineering, Maastricht University, Maastricht, The Netherlands
| | - C Cavinato
- LMGC, Universite' Montpellier, CNRS, Montpellier, France
| | - J D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA.
| | - C A Figueroa
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Surgery, University of Michigan, Ann Arbor, MI, USA
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11
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Dong H, Ferruzzi J, Liu M, Brewster LP, Leshnower BG, Gleason RL. Effect of Aging, Sex, and Gene (Fbln5) on Arterial Stiffness of Mice: 20 Weeks Adult Fbln5-knockout Mice Have Older Arteries than 100 Weeks Wild-Type Mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.30.542920. [PMID: 37398425 PMCID: PMC10312538 DOI: 10.1101/2023.05.30.542920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
The arterial stiffening is a strong independent predictor of cardiovascular risk and has been used to characterize the biological age of arteries ('arterial age'). Here we revealed that the Fbln5 gene knockout (Fbln5 -/- ) significantly increases the arterial stiffening for both male and female mice. We also showed that the arterial stiffening increases with natural aging, but the stiffening effect of Fbln5 -/- is much more severe than aging. The arterial stiffening of 20 weeks old mice with Fbln5 -/- is much higher than that at 100 weeks in wild-type (Fbln5 +/+ ) mice, which indicates that 20 weeks mice (equivalent to ∼26 years old humans) with Fbln5 -/- have older arteries than 100 weeks wild-type mice (equivalent to ∼77 years humans). Histological microstructure changes of elastic fibers in the arterial tissue elucidate the underlying mechanism of the increase of arterial stiffening due to Fbln5-knockout and aging. These findings provide new insights to reverse 'arterial age' due to abnormal mutations of Fbln5 gene and natural aging. This work is based on a total of 128 biaxial testing samples of mouse arteries and our recently developed unified-fiber-distribution (UFD) model. The UFD model considers the fibers in the arterial tissue as a unified distribution, which is more physically consistent with the real fiber distribution of arterial tissues than the popular fiber-family-based models (e.g., the well-know Gasser-Ogden-Holzapfel [GOH] model) that separate the fiber distribution into several fiber families. Thus, the UFD model achieves better accuracies with less material parameters. To our best knowledge, the UFD model is the only existing accurate model that could capture the property/stiffness differences between different groups of the experimental data discussed here.
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12
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Tarraf SA, Kramer B, Vianna E, Gillespie C, Germano E, Emerton KB, Amini R, Colbrunn R, Hargrave J, Roselli EE, Bellini C. Lengthwise regional mechanics of the human aneurysmal ascending thoracic aorta. Acta Biomater 2023; 162:266-277. [PMID: 36944405 PMCID: PMC10148908 DOI: 10.1016/j.actbio.2023.03.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 02/16/2023] [Accepted: 03/15/2023] [Indexed: 03/23/2023]
Abstract
The prognosis of patients undergoing emergency endovascular repair of ascending thoracic aortic aneurysm (ATAA) depends on defect location, with root disease bearing worse outcomes than proximal or distal aortopathy. We speculate that a spatial gradient in aneurysmal tissue mechanics through the length of the ascending thoracic aorta may fuel noted survival discrepancies. To this end, we performed planar biaxial testing on 153 root, proximal, and distal segments of ATAA samples collected from 80 patients receiving elective open surgical repair. Following data averaging via surface fitting-based interpolation of strain-controlled protocols, we combined in-vitro and in-vivo measurements of loads and geometry to resolve inflation-extension kinematics and evaluate mechanical metrics of stress, stiffness, and energy at consistent deformation levels. Representative (averaged) experimental data and simulated in-vivo conditions revealed significantly larger biaxial stiffness at the root compared to either proximal or distal tissues, which persisted as the entire aorta stiffened during aging. Advancing age further reduced biaxial stretch and energy storage, a measure of aortic function, across all ATAA segments. Importantly, age emerged as a stronger predictor of tissue mechanics in ATAA disease than either bicuspid aortic valve or connective tissue disorders. Besides strengthening the general understanding of aneurysmal disease, our findings provide specifications to customize the design of stent-grafts for the treatment of ATAA disease. Optimization of deployment and interaction of novel endovascular devices with the local native environment is expected to carry significant potential for improving clinical outcomes. STATEMENT OF SIGNIFICANCE: Elucidating the lengthwise regional mechanics of ascending thoracic aortic aneurysms (ATAAs) is critical for the design of endovascular devices tailored to the ascending aorta. Stent-grafts provide a less invasive alternative to support the long-term survival of ATAA patients ineligible for open surgical repair. In this study, we developed a numerical framework that combines semi-inverse constitutive and forward modeling with in-vitro and in-vivo data to extract mechanical descriptors of ATAA tissue behavior at physiologically meaningful deformation. Moving distally from the aortic root to the first ascending aortic branch, we observed a progressive decline in biaxial stiffness. Furthermore, we showed that aging leads to reduced aortic function and is a stronger predictor of mechanics than either valve morphology or underlying syndromic disorder.
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Affiliation(s)
- Samar A Tarraf
- Department of Bioengineering, Northeastern University, 360 Huntington Ave., Boston, MA, 02125 USA
| | - Benjamin Kramer
- Aortic Center, Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, Cleveland, OH, USA
| | - Emily Vianna
- Aortic Center, Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, Cleveland, OH, USA
| | - Callan Gillespie
- Department of Biomedical Engineering, BioRobotics and Mechanical Testing Core, Cleveland Clinic, Cleveland, OH, USA
| | - Emídio Germano
- Aortic Center, Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, Cleveland, OH, USA
| | - Kelly B Emerton
- Aortic Center, Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, Cleveland, OH, USA
| | - Rouzbeh Amini
- Department of Bioengineering, Northeastern University, 360 Huntington Ave., Boston, MA, 02125 USA; Department of Mechanical and Industrial Engineering, Northeastern University, 360 Huntington Ave., Boston, MA, 02125 USA
| | - Robb Colbrunn
- Department of Biomedical Engineering, BioRobotics and Mechanical Testing Core, Cleveland Clinic, Cleveland, OH, USA
| | - Jennifer Hargrave
- Department of Cardiothoracic Anesthesiology, Cleveland Clinic, Cleveland, OH, USA
| | - Eric E Roselli
- Aortic Center, Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, Cleveland, OH, USA; Department of Biomedical Engineering, BioRobotics and Mechanical Testing Core, Cleveland Clinic, Cleveland, OH, USA
| | - Chiara Bellini
- Department of Bioengineering, Northeastern University, 360 Huntington Ave., Boston, MA, 02125 USA.
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Chen M, Cavinato C, Hansen J, Tanaka K, Ren P, Hassab A, Li DS, Youshao E, Tellides G, Iyengar R, Humphrey JD, Schwartz MA. FN (Fibronectin)-Integrin α5 Signaling Promotes Thoracic Aortic Aneurysm in a Mouse Model of Marfan Syndrome. Arterioscler Thromb Vasc Biol 2023; 43:e132-e150. [PMID: 36994727 PMCID: PMC10133209 DOI: 10.1161/atvbaha.123.319120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 03/20/2023] [Indexed: 03/31/2023]
Abstract
BACKGROUND Marfan syndrome, caused by mutations in the gene for fibrillin-1, leads to thoracic aortic aneurysms (TAAs). Phenotypic modulation of vascular smooth muscle cells (SMCs) and ECM (extracellular matrix) remodeling are characteristic of both nonsyndromic and Marfan aneurysms. The ECM protein FN (fibronectin) is elevated in the tunica media of TAAs and amplifies inflammatory signaling in endothelial and SMCs through its main receptor, integrin α5β1. We investigated the role of integrin α5-specific signals in Marfan mice in which the cytoplasmic domain of integrin α5 was replaced with that of integrin α2 (denoted α5/2 chimera). METHODS We crossed α5/2 chimeric mice with Fbn1mgR/mgR mice (mgR model of Marfan syndrome) to evaluate the survival rate and pathogenesis of TAAs among wild-type, α5/2, mgR, and α5/2 mgR mice. Further biochemical and microscopic analysis of porcine and mouse aortic SMCs investigated molecular mechanisms by which FN affects SMCs and subsequent development of TAAs. RESULTS FN was elevated in the thoracic aortas from Marfan patients, in nonsyndromic aneurysms, and in mgR mice. The α5/2 mutation greatly prolonged survival of Marfan mice, with improved elastic fiber integrity, mechanical properties, SMC density, and SMC contractile gene expression. Furthermore, plating of wild-type SMCs on FN decreased contractile gene expression and activated inflammatory pathways whereas α5/2 SMCs were resistant. These effects correlated with increased NF-kB activation in cultured SMCs and mgR aortas, which was alleviated by the α5/2 mutation or NF-kB inhibition. CONCLUSIONS FN-integrin α5 signaling is a significant driver of TAA in the mgR mouse model. This pathway thus warrants further investigation as a therapeutic target.
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Affiliation(s)
- Minghao Chen
- Cardiovascular Research Center (M.C., K.T., M.A.S.), Yale School of Medicine, New Haven, CT
| | - Cristina Cavinato
- Department of Biomedical Engineering, Yale University, New Haven, CT (C.C., D.S.L., E.Y., J.D.H., M.A.S.)
| | - Jens Hansen
- Department of Pharmacological Sciences and Institute for Systems Biomedicine, Icahn School of Medicine at Mount Sinai, New York (J.H., R.I.)
| | - Keiichiro Tanaka
- Cardiovascular Research Center (M.C., K.T., M.A.S.), Yale School of Medicine, New Haven, CT
| | - Pengwei Ren
- Department of Surgery (P.R., A.H., G.T., M.A.S.), Yale School of Medicine, New Haven, CT
| | - Abdulrahman Hassab
- Department of Surgery (P.R., A.H., G.T., M.A.S.), Yale School of Medicine, New Haven, CT
| | - David S Li
- Department of Biomedical Engineering, Yale University, New Haven, CT (C.C., D.S.L., E.Y., J.D.H., M.A.S.)
| | - Eric Youshao
- Department of Biomedical Engineering, Yale University, New Haven, CT (C.C., D.S.L., E.Y., J.D.H., M.A.S.)
| | - George Tellides
- Department of Surgery (P.R., A.H., G.T., M.A.S.), Yale School of Medicine, New Haven, CT
- Vascular Biology and Therapeutics Program (G.T., J.D.H.), Yale School of Medicine, New Haven, CT
| | - Ravi Iyengar
- Department of Pharmacological Sciences and Institute for Systems Biomedicine, Icahn School of Medicine at Mount Sinai, New York (J.H., R.I.)
| | - Jay D Humphrey
- Vascular Biology and Therapeutics Program (G.T., J.D.H.), Yale School of Medicine, New Haven, CT
- Department of Biomedical Engineering, Yale University, New Haven, CT (C.C., D.S.L., E.Y., J.D.H., M.A.S.)
| | - Martin A Schwartz
- Cardiovascular Research Center (M.C., K.T., M.A.S.), Yale School of Medicine, New Haven, CT
- Department of Surgery (P.R., A.H., G.T., M.A.S.), Yale School of Medicine, New Haven, CT
- Departments of Medicine (Cardiology) and Cell Biology (M.A.S.), Yale School of Medicine, New Haven, CT
- Department of Biomedical Engineering, Yale University, New Haven, CT (C.C., D.S.L., E.Y., J.D.H., M.A.S.)
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14
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Murtada SI, Mikush N, Wang M, Ren P, Kawamura Y, Ramachandra AB, Li DS, Braddock DT, Tellides G, Gordon LB, Humphrey JD. Lonafarnib improves cardiovascular function and survival in a mouse model of Hutchinson-Gilford progeria syndrome. eLife 2023; 12:82728. [PMID: 36930696 PMCID: PMC10023154 DOI: 10.7554/elife.82728] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 03/09/2023] [Indexed: 03/18/2023] Open
Abstract
Clinical trials have demonstrated that lonafarnib, a farnesyltransferase inhibitor, extends the lifespan in patients afflicted by Hutchinson-Gilford progeria syndrome, a devastating condition that accelerates many characteristics of aging and results in premature death due to cardiovascular sequelae. The US Food and Drug Administration approved Zokinvy (lonafarnib) in November 2020 for treating these patients, yet a detailed examination of drug-associated effects on cardiovascular structure, properties, and function has remained wanting. In this paper, we report encouraging outcomes of daily post-weaning treatment with lonafarnib on the composition and biomechanical phenotype of elastic and muscular arteries as well as associated cardiac function in a well-accepted mouse model of progeria that exhibits severe perimorbid cardiovascular disease. Lonafarnib resulted in 100% survival of the treated progeria mice to the study end-point (time of 50% survival of untreated mice), with associated improvements in arterial structure and function working together to significantly reduce pulse wave velocity and improve left ventricular diastolic function. By contrast, neither treatment with the mTOR inhibitor rapamycin alone nor dual treatment with lonafarnib plus rapamycin improved outcomes over that achieved with lonafarnib monotherapy.
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Affiliation(s)
- Sae-Il Murtada
- Department of Biomedical Engineering, Yale UniversityNew HavenUnited States
| | - Nicole Mikush
- Translational Research Imaging Center, Yale UniversityNew HavenUnited States
| | - Mo Wang
- Department of Surgery, Yale UniversityNew HavenUnited States
| | - Pengwei Ren
- Department of Surgery, Yale UniversityNew HavenUnited States
| | - Yuki Kawamura
- Department of Biomedical Engineering, Yale UniversityNew HavenUnited States
| | | | - David S Li
- Department of Biomedical Engineering, Yale UniversityNew HavenUnited States
| | | | - George Tellides
- Department of Surgery, Yale UniversityNew HavenUnited States
- Vascular Biology and Therapeutics Program, Yale UniversityNew HavenUnited States
| | - Leslie B Gordon
- Department of Pediatrics, Hasbro Children's Hospital and Warren Albert Medical School, Brown UniversityProvidenceUnited States
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale UniversityNew HavenUnited States
- Vascular Biology and Therapeutics Program, Yale UniversityNew HavenUnited States
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15
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Murtada SI, Kawamura Y, Cavinato C, Wang M, Ramachandra AB, Spronck B, Tellides G, Humphrey JD. Smooth Muscle Cell Death Drives an Osteochondrogenic Phenotype and Severe Proximal Vascular Disease in Progeria. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.10.523266. [PMID: 36711514 PMCID: PMC9882088 DOI: 10.1101/2023.01.10.523266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Hutchinson-Gilford Progeria Syndrome results in rapid aging and severe cardiovascular sequelae that accelerate near end of life. We associate progressive deterioration of arterial structure and function with single cell transcriptional changes, which reveals a rapid disease process in proximal elastic arteries that largely spares distal muscular arteries. These data suggest a novel sequence of progressive vascular disease in progeria: initial extracellular matrix remodeling followed by mechanical stress-induced smooth muscle cell death in proximal arteries, leading a subset of remnant smooth muscle cells to an osteochondrogenic phenotypic modulation that results in an accumulation of proteoglycans that thickens the wall and increases pulse wave velocity, with late calcification exacerbating these effects. Increased pulse wave velocity drives left ventricular diastolic dysfunction, the primary diagnosis in progeria children. Mitigating smooth muscle cell loss / phenotypic modulation promises to have important cardiovascular implications in progeria patients.
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Affiliation(s)
- Sae-Il Murtada
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Yuki Kawamura
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, USA
| | - Cristina Cavinato
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Mo Wang
- Department of Surgery, Yale School of Medicine, New Haven, CT, USA
| | | | - Bart Spronck
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
- Department of Biomedical Engineering, Maastricht University, Maastricht, Netherlands
| | - George Tellides
- Department of Surgery, Yale School of Medicine, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA
| | - Jay D. Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA
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16
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Zhang E, Spronck B, Humphrey JD, Karniadakis GE. G2Φnet: Relating genotype and biomechanical phenotype of tissues with deep learning. PLoS Comput Biol 2022; 18:e1010660. [PMID: 36315608 PMCID: PMC9668200 DOI: 10.1371/journal.pcbi.1010660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/16/2022] [Accepted: 10/17/2022] [Indexed: 11/05/2022] Open
Abstract
Many genetic mutations adversely affect the structure and function of load-bearing soft tissues, with clinical sequelae often responsible for disability or death. Parallel advances in genetics and histomechanical characterization provide significant insight into these conditions, but there remains a pressing need to integrate such information. We present a novel genotype-to-biomechanical phenotype neural network (G2Φnet) for characterizing and classifying biomechanical properties of soft tissues, which serve as important functional readouts of tissue health or disease. We illustrate the utility of our approach by inferring the nonlinear, genotype-dependent constitutive behavior of the aorta for four mouse models involving defects or deficiencies in extracellular constituents. We show that G2Φnet can infer the biomechanical response while simultaneously ascribing the associated genotype by utilizing limited, noisy, and unstructured experimental data. More broadly, G2Φnet provides a powerful method and a paradigm shift for correlating genotype and biomechanical phenotype quantitatively, promising a better understanding of their interplay in biological tissues.
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Affiliation(s)
- Enrui Zhang
- Division of Applied Mathematics, Brown University, Providence, Rhode Island, United States of America
| | - Bart Spronck
- Department of Biomedical Engineering, Maastricht University, Maastricht, the Netherlands
| | - Jay D. Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States of America
| | - George Em Karniadakis
- Division of Applied Mathematics, Brown University, Providence, Rhode Island, United States of America
- School of Engineering, Brown University, Providence, Rhode Island, United States of America
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17
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Biodegradable external wrapping promotes favorable adaptation in an ovine vein graft model. Acta Biomater 2022; 151:414-425. [PMID: 35995404 DOI: 10.1016/j.actbio.2022.08.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 08/09/2022] [Accepted: 08/15/2022] [Indexed: 11/23/2022]
Abstract
Vein grafts, the most commonly used conduits in multi-vessel coronary artery bypass grafting surgery, have high intermediate- and long-term failure rates. The abrupt and marked increase in hemodynamic loads on the vein graft is a known contributor to failure. Recent computational modeling suggests that veins can more successfully adapt to an increase in mechanical load if the rate of loading is gradual. Applying an external wrap or support at the time of surgery is one way to reduce the transmural load, and this approach has improved performance relative to an unsupported vein graft in several animal studies. Yet, a clinical trial in humans has shown benefits and drawbacks, and mechanisms by which an external wrap affects vein graft adaptation remain unknown. This study aims to elucidate such mechanisms using a multimodal experimental and computational data collection pipeline. We quantify morphometry using magnetic resonance imaging, mechanics using biaxial testing, hemodynamics using computational fluid dynamics, structure using histology, and transcriptional changes using bulk RNA-sequencing in an ovine carotid-jugular interposition vein graft model, without and with an external biodegradable wrap that allows loads to increase gradually. We show that a biodegradable external wrap promotes luminal uniformity, physiological wall shear stress, and a consistent vein graft phenotype, namely, it prevents over-distension, over-thickening, intimal hyperplasia, and inflammation, and it preserves mechanotransduction. These mechanobiological insights into vein graft adaptation in the presence of an external support can inform computational growth and remodeling models of external support and facilitate design and manufacturing of next-generation external wrapping devices. STATEMENT OF SIGNIFICANCE: External mechanical support is emerging as a promising technology to prevent vein graft failure following coronary bypass graft surgery. While variants of this technology are currently under investigation in clinical trials, the fundamental mechanisms of adaptation remain poorly understood. We employ an ovine carotid-jugular interposition vein graft model, with and without an external biodegradable wrap to provide mechanical support, and probe vein graft adaptation using a multimodal experimental and computational data collection pipeline. We quantify morphometry using magnetic resonance imaging, mechanics using biaxial testing, fluid flow using computational fluid dynamics, vascular composition and structure using histology, and transcriptional changes using bulk RNA sequencing. We show that the wrap mitigates vein graft failure by promoting multiple adaptive mechanisms (across biological scales).
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18
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Spronck B, Ramachandra AB, Moriyama L, Toczek J, Han J, Sadeghi MM, Humphrey JD. Deletion of matrix metalloproteinase-12 compromises mechanical homeostasis and leads to an aged aortic phenotype in young mice. J Biomech 2022; 141:111179. [PMID: 35759974 PMCID: PMC9585962 DOI: 10.1016/j.jbiomech.2022.111179] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 06/03/2022] [Accepted: 06/06/2022] [Indexed: 11/28/2022]
Abstract
Mechanical homeostasis emerges following normal development of the arterial wall and requires thereafter a slow balanced degradation and deposition of extracellular matrix constituents within an unchanging mechanical state. Recent findings suggest that homeostasis is compromised in arterial aging, which contributes to the structural stiffening that is characteristic of aged central arteries. Matrix metalloproteinases (MMPs) have strong proteolytic activity and play fundamental roles in matrix turnover. Here, we use Mmp12-/- mice to examine effects of a potent metalloelastase, MMP-12, on the biomechanical phenotype of the thoracic and abdominal aorta in young and naturally aged mice. A key finding is that germline deletion of the gene (Mmp12) that encodes MMP-12 alters biomechanical properties from normal more in young adult than in older adult mice. Consequently, percent changes in biomechanical properties during aortic aging are greater in wild-type than in MMP-12 deficient mice, though with similar overall decreases in elastic energy storage and distensibility and increases in calculated pulse wave velocity. Reduced elastic energy storage compromises the ability of the aorta to augment antegrade and retrograde blood flow while an increased pulse wave velocity can adversely affect end organs, both conditions being characteristic of aortic aging in humans. In summary, MMP-12 is fundamental for establishing homeostatic values of biomechanical metrics in the aorta and its absence leads to a pre-aged aortic phenotype in young mice.
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Affiliation(s)
- Bart Spronck
- Department of Biomedical Engineering, School of Engineering and Applied Science, Yale University, New Haven, CT, USA; Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, the Netherlands.
| | - Abhay B Ramachandra
- Department of Biomedical Engineering, School of Engineering and Applied Science, Yale University, New Haven, CT, USA
| | - Lauren Moriyama
- Department of Biomedical Engineering, School of Engineering and Applied Science, Yale University, New Haven, CT, USA
| | - Jakub Toczek
- Cardiovascular Medicine and Cardiovascular Research Center, Yale School of Medicine, New Haven, CT, USA; Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Jinah Han
- Cardiovascular Medicine and Cardiovascular Research Center, Yale School of Medicine, New Haven, CT, USA; Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Mehran M Sadeghi
- Cardiovascular Medicine and Cardiovascular Research Center, Yale School of Medicine, New Haven, CT, USA; Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA; Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA
| | - Jay D Humphrey
- Department of Biomedical Engineering, School of Engineering and Applied Science, Yale University, New Haven, CT, USA; Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA
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19
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Linka K, Cavinato C, Humphrey JD, Cyron CJ. Predicting and understanding arterial elasticity from key microstructural features by bidirectional deep learning. Acta Biomater 2022; 147:63-72. [PMID: 35643194 DOI: 10.1016/j.actbio.2022.05.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 05/19/2022] [Accepted: 05/19/2022] [Indexed: 01/15/2023]
Abstract
Microstructural features and mechanical properties are closely related in all soft biological tissues. Both yet exhibit considerable inter-individual differences and are affected by factors such as aging and disease and its progression. Histological analysis, modern in situ imaging, and biomechanical testing have deepened our understanding of these complex interrelations, yet two key questions remain: (1) Given the specific microstructure, can one predict the macroscopic mechanical properties without mechanical testing? (2) Can one quantify individual contributions of the different microstructural features to the macroscopic mechanical properties in an automated, systematic and largely unbiased way? Here we propose a bidirectional deep learning architecture to address these two questions. Our architecture uses data from standard histological analyses, two-photon microscopy and biaxial biomechanical testing. Its capabilities are demonstrated by predicting with high accuracy (R2=0.92) the evolving mechanical properties of the murine aorta during maturation and aging. Moreover, our architecture reveals that the extracellular matrix composition and organization are the most prominent factors governing the macroscopic mechanical properties of the tissues studied herein. STATEMENT OF SIGNIFICANCE: .
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Affiliation(s)
- Kevin Linka
- Institute for Continuum and Material Mechanics, Hamburg University of Technology, Hamburg, Germany
| | - Cristina Cavinato
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA; Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA
| | - Christian J Cyron
- Institute for Continuum and Material Mechanics, Hamburg University of Technology, Hamburg, Germany; Institute of Material Systems Modeling, Helmholtz-Zentrum Hereon, Geesthacht, Germany.
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20
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Gkousioudi A, Yu X, Ferruzzi J, Qian J, Wainford RD, Seta F, Zhang Y. Biomechanical Properties of Mouse Carotid Arteries With Diet-Induced Metabolic Syndrome and Aging. Front Bioeng Biotechnol 2022; 10:862996. [PMID: 35392404 PMCID: PMC8980683 DOI: 10.3389/fbioe.2022.862996] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/07/2022] [Indexed: 12/15/2022] Open
Abstract
Metabolic syndrome increases the risk of cardiovascular diseases. Arteries gradually stiffen with aging; however, it can be worsened by the presence of conditions associated with metabolic syndrome. In this study, we investigated the combined effects of diet-induced metabolic syndrome and aging on the biomechanical properties of mouse common carotid arteries (CCA). Male mice at 2 months of age were fed a normal or a high fat and high sucrose (HFHS) diet for 2 (young group), 8 (adult group) and 18-20 (old group) months. CCAs were excised and subjected to in vitro biaxial inflation-extension tests and the Cauchy stress-stretch relationships were determined in both the circumferential and longitudinal directions. The elastic energy storage of CCAs was obtained using a four-fiber family constitutive model, while the material stiffness in the circumferential and longitudinal directions was computed. Our study showed that aging is a dominant factor affecting arterial remodeling in the adult and old mice, to a similar extent, with stiffening manifested with a significantly reduced capability of energy storage by ∼50% (p < 0.05) and decreases in material stiffness and stress (p < 0.05), regardless of diet. On the other hand, high fat high sucrose diet resulted in an accelerated arterial remodeling in the young group at pre-diabetic stage by affecting the circumferential material stiffness and stress (p < 0.05), which was eventually overshadowed by aging progression. These findings have important implications on the effects of metabolic syndrome on elastic arteries in the younger populations.
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Affiliation(s)
- Anastasia Gkousioudi
- Department of Mechanical Engineering, Boston University, Boston, MA, United States
| | - Xunjie Yu
- Department of Mechanical Engineering, Boston University, Boston, MA, United States
| | - Jacopo Ferruzzi
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Juncheng Qian
- Department of Mechanical Engineering, Boston University, Boston, MA, United States
| | - Richard D. Wainford
- Department of Pharmacology and Experimental Therapeutics, The Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
| | - Francesca Seta
- Vascular Biology Section, The Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, United States
| | - Yanhang Zhang
- Department of Mechanical Engineering, Boston University, Boston, MA, United States
- Division of Materials Science and Engineering, Boston University, Boston, MA, United States
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
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21
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Guang Y, Cocciolone AJ, Crandall CL, Johnston BB, Setton LA, Wagenseil JE. A multiphasic model for determination of water and solute transport across the arterial wall: effects of elastic fiber defects. ARCHIVE OF APPLIED MECHANICS = INGENIEUR-ARCHIV 2022; 92:447-459. [PMID: 35386426 PMCID: PMC8983017 DOI: 10.1007/s00419-021-01985-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Transport of solute across the arterial wall is a process driven by both convection and diffusion. In disease, the elastic fibers in the arterial wall are disrupted and lead to altered fluid and mass transport kinetics. A computational mixture model was used to numerically match previously published data of fluid and solute permeation experiments in groups of mouse arteries with genetic (knockout of fibulin-5) or chemical (treatment with elastase) disruption of elastic fibers. A biphasic model of fluid permeation indicated the governing property to be the hydraulic permeability, which was estimated to be 1.52×10-9, 1.01×10-8, and 1.07×10-8 mm4/μN.s for control, knockout, and elastase groups, respectively. A multiphasic model incorporating solute transport was used to estimate effective diffusivities that were dependent on molecular weight, consistent with expected transport behaviors in multiphasic biological tissues. The effective diffusivity for the 4 kDA FITC-dextran solute, but not the 70 or 150 kDa FITC-dextran solutes, was dependent on elastic fiber structure, with increasing values from control to knockout to elastase groups, suggesting that elastic fiber disruption affects transport of lower molecular weight solutes. The model used here sets the groundwork for future work investigating transport through the arterial wall.
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Affiliation(s)
- Young Guang
- Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
| | - Austin J Cocciolone
- Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
| | - Christie L Crandall
- Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, MO, USA
| | - Benjamin B Johnston
- Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
| | - Lori A Setton
- Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
| | - Jessica E Wagenseil
- Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, MO, USA
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22
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Cavinato C, Chen M, Weiss D, Ruiz-Rodríguez MJ, Schwartz MA, Humphrey JD. Progressive Microstructural Deterioration Dictates Evolving Biomechanical Dysfunction in the Marfan Aorta. Front Cardiovasc Med 2021; 8:800730. [PMID: 34977201 PMCID: PMC8716484 DOI: 10.3389/fcvm.2021.800730] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 11/23/2021] [Indexed: 11/13/2022] Open
Abstract
Medial deterioration leading to thoracic aortic aneurysms arises from multiple causes, chief among them mutations to the gene that encodes fibrillin-1 and leads to Marfan syndrome. Fibrillin-1 microfibrils associate with elastin to form elastic fibers, which are essential structural, functional, and instructional components of the normal aortic wall. Compromised elastic fibers adversely impact overall structural integrity and alter smooth muscle cell phenotype. Despite significant progress in characterizing clinical, histopathological, and mechanical aspects of fibrillin-1 related aortopathies, a direct correlation between the progression of microstructural defects and the associated mechanical properties that dictate aortic functionality remains wanting. In this paper, age-matched wild-type, Fbn1 C1041G/+, and Fbn1 mgR/mgR mouse models were selected to represent three stages of increasing severity of the Marfan aortic phenotype. Ex vivo multiphoton imaging and biaxial mechanical testing of the ascending and descending thoracic aorta under physiological loading conditions demonstrated that elastic fiber defects, collagen fiber remodeling, and cell reorganization increase with increasing dilatation. Three-dimensional microstructural characterization further revealed radial patterns of medial degeneration that become more uniform with increasing dilatation while correlating strongly with increased circumferential material stiffness and decreased elastic energy storage, both of which comprise aortic functionality.
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Affiliation(s)
- Cristina Cavinato
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States
| | - Minghao Chen
- Cardiovascular Research Center and Department of Internal Medicine (Cardiology), Yale School of Medicine, New Haven, CT, United States
| | - Dar Weiss
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States
| | - Maria Jesús Ruiz-Rodríguez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) and Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Martin A. Schwartz
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States
- Cardiovascular Research Center and Department of Internal Medicine (Cardiology), Yale School of Medicine, New Haven, CT, United States
| | - Jay D. Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States
- Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, United States
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23
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Clark-Patterson GL, Roy S, Desrosiers L, Knoepp LR, Sen A, Miller KS. Role of fibulin-5 insufficiency and prolapse progression on murine vaginal biomechanical function. Sci Rep 2021; 11:20956. [PMID: 34697337 PMCID: PMC8546087 DOI: 10.1038/s41598-021-00351-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/31/2021] [Indexed: 02/04/2023] Open
Abstract
The vagina plays a critical role in supporting the pelvic organs and loss of support leads to pelvic organ prolapse. It is unknown what microstructural changes influence prolapse progression nor how decreased elastic fibers contributes to vaginal remodeling and smooth muscle contractility. The objective for this study was to evaluate the effect of fibulin-5 haploinsufficiency, and deficiency with progressive prolapse on the biaxial contractile and biomechanical function of the murine vagina. Vaginas from wildtype (n = 13), haploinsufficient (n = 13), and deficient mice with grade 1 (n = 9) and grade 2 or 3 (n = 9) prolapse were explanted for biaxial contractile and biomechanical testing. Multiaxial histology (n = 3/group) evaluated elastic and collagen fiber microstructure. Western blotting quantified protein expression (n = 6/group). A one-way ANOVA or Kruskal-Wallis test evaluated statistical significance. Pearson's or Spearman's test determined correlations with prolapse grade. Axial contractility decreased with fibulin-5 deficiency and POP (p < 0.001), negatively correlated with prolapse grade (ρ = - 0.80; p < 0.001), and positively correlated with muscularis elastin area fraction (ρ = - 0.78; p = 0.004). Circumferential (ρ = 0.71; p < 0.001) and axial (ρ = 0.69; p < 0.001) vaginal wall stresses positively correlated with prolapse grade. These findings demonstrated that fibulin-5 deficiency and prolapse progression decreased vaginal contractility and increased vaginal wall stress. Future work is needed to better understand the processes that contribute to prolapse progression in order to guide diagnostic, preventative, and treatment strategies.
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Affiliation(s)
| | - Sambit Roy
- Department of Animal Sciences, Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, 48824, USA
| | - Laurephile Desrosiers
- Department of Female Pelvic Medicine and Reconstructive Surgery, University of Queensland Ochsner Clinical School, New Orleans, 70121, USA
| | - Leise R Knoepp
- Department of Female Pelvic Medicine and Reconstructive Surgery, University of Queensland Ochsner Clinical School, New Orleans, 70121, USA
| | - Aritro Sen
- Department of Animal Sciences, Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, 48824, USA
| | - Kristin S Miller
- Department of Biomedical Engineering, Tulane University, New Orleans, 70118, USA.
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24
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Manning EP, Ramachandra AB, Schupp JC, Cavinato C, Raredon MSB, Bärnthaler T, Cosme C, Singh I, Tellides G, Kaminski N, Humphrey JD. Mechanisms of Hypoxia-Induced Pulmonary Arterial Stiffening in Mice Revealed by a Functional Genetics Assay of Structural, Functional, and Transcriptomic Data. Front Physiol 2021; 12:726253. [PMID: 34594238 PMCID: PMC8478173 DOI: 10.3389/fphys.2021.726253] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/19/2021] [Indexed: 01/08/2023] Open
Abstract
Hypoxia adversely affects the pulmonary circulation of mammals, including vasoconstriction leading to elevated pulmonary arterial pressures. The clinical importance of changes in the structure and function of the large, elastic pulmonary arteries is gaining increased attention, particularly regarding impact in multiple chronic cardiopulmonary conditions. We establish a multi-disciplinary workflow to understand better transcriptional, microstructural, and functional changes of the pulmonary artery in response to sustained hypoxia and how these changes inter-relate. We exposed adult male C57BL/6J mice to normoxic or hypoxic (FiO2 10%) conditions. Excised pulmonary arteries were profiled transcriptionally using single cell RNA sequencing, imaged with multiphoton microscopy to determine microstructural features under in vivo relevant multiaxial loading, and phenotyped biomechanically to quantify associated changes in material stiffness and vasoactive capacity. Pulmonary arteries of hypoxic mice exhibited an increased material stiffness that was likely due to collagen remodeling rather than excessive deposition (fibrosis), a change in smooth muscle cell phenotype reflected by decreased contractility and altered orientation aligning these cells in the same direction as the remodeled collagen fibers, endothelial proliferation likely representing endothelial-to-mesenchymal transitioning, and a network of cell-type specific transcriptomic changes that drove these changes. These many changes resulted in a system-level increase in pulmonary arterial pulse wave velocity, which may drive a positive feedback loop exacerbating all changes. These findings demonstrate the power of a multi-scale genetic-functional assay. They also highlight the need for systems-level analyses to determine which of the many changes are clinically significant and may be potential therapeutic targets.
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Affiliation(s)
- Edward P Manning
- Pulmonary, Critical Care and Sleep Medicine, Yale School of Medicine, New Haven, CT, United States.,VA Connecticut Healthcare System, West Haven, CT, United States
| | - Abhay B Ramachandra
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States
| | - Jonas C Schupp
- Pulmonary, Critical Care and Sleep Medicine, Yale School of Medicine, New Haven, CT, United States.,Respiratory Medicine, Hannover Medical School, Hannover, Germany
| | - Cristina Cavinato
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States
| | - Micha Sam Brickman Raredon
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States.,Vascular Biology and Therapeutics Program, Yale University, New Haven, CT, United States.,Department of Anesthesiology, Yale School of Medicine, New Haven, CT, United States
| | - Thomas Bärnthaler
- Pulmonary, Critical Care and Sleep Medicine, Yale School of Medicine, New Haven, CT, United States.,Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Graz, Austria
| | - Carlos Cosme
- Pulmonary, Critical Care and Sleep Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Inderjit Singh
- Pulmonary, Critical Care and Sleep Medicine, Yale School of Medicine, New Haven, CT, United States
| | - George Tellides
- VA Connecticut Healthcare System, West Haven, CT, United States.,Vascular Biology and Therapeutics Program, Yale University, New Haven, CT, United States.,Department of Surgery, Yale School of Medicine, New Haven, CT, United States
| | - Naftali Kaminski
- Pulmonary, Critical Care and Sleep Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States.,Vascular Biology and Therapeutics Program, Yale University, New Haven, CT, United States
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25
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Ogola BO, Clark GL, Abshire CM, Harris NR, Gentry KL, Gunda SS, Kilanowski-Doroh I, Wong TJ, Visniauskas B, Lawrence DJ, Zimmerman MA, Bayer CL, Groban L, Miller KS, Lindsey SH. Sex and the G Protein-Coupled Estrogen Receptor Impact Vascular Stiffness. Hypertension 2021; 78:e1-e14. [PMID: 34024124 PMCID: PMC8192475 DOI: 10.1161/hypertensionaha.120.16915] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Benard O. Ogola
- Tulane University, Department of Pharmacology, New Orleans, LA, USA
| | - Gabrielle L. Clark
- Tulane University, Department of Biomedical Engineering, New Orleans, LA, USA
| | - Caleb M. Abshire
- Tulane University, Department of Pharmacology, New Orleans, LA, USA
| | | | - Kaylee L. Gentry
- Tulane University, Department of Pharmacology, New Orleans, LA, USA
| | - Shreya S. Gunda
- Tulane University, Department of Pharmacology, New Orleans, LA, USA
| | | | - Tristen J. Wong
- Tulane University, Department of Pharmacology, New Orleans, LA, USA
| | | | - Dylan J. Lawrence
- Tulane University, Department of Biomedical Engineering, New Orleans, LA, USA
| | | | - Carolyn L. Bayer
- Tulane University, Department of Biomedical Engineering, New Orleans, LA, USA
| | - Leanne Groban
- Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Kristin S. Miller
- Tulane University, Department of Biomedical Engineering, New Orleans, LA, USA
| | - Sarah H. Lindsey
- Tulane University, Department of Pharmacology, New Orleans, LA, USA
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26
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Lane BA, Chakrabarti M, Ferruzzi J, Azhar M, Eberth JF. Mechanics of ascending aortas from TGFβ-1, -2, -3 haploinsufficient mice and elastase-induced aortopathy. J Biomech 2021; 125:110543. [PMID: 34174532 DOI: 10.1016/j.jbiomech.2021.110543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 05/23/2021] [Accepted: 05/31/2021] [Indexed: 10/21/2022]
Abstract
Transforming growth factor-beta (TGFβ-1, -2, -3) ligands act through a common receptor complex yet each is expressed in a unique and overlapping fashion throughout development. TGFβ plays a role in extra-cellular matrix composition with mutations to genes encoding TGFβ and TGFβ signaling molecules contributing to diverse and deadly thoracic aortopathies common in Loeys-Dietz syndrome (LDS). In this investigation, we studied the TGFβ ligand-specific mechanical phenotype of ascending thoracic aortas (ATA) taken from 4-to-6 months-old Tgfb1+/-, Tgfb2+/-, and Tgfb3+/- mice, their wild-type (WT) controls, and an elastase infusion model representative of severe elastolysis. Heterozygous mice were studied at an age without dilation to elucidate potential pre-aortopathic mechanical cues. Our findings indicate that ATAs from Tgfb2+/- mice demonstrated significant wall thickening, a corresponding decrease in biaxial stress, decreased biaxial stiffness, and a decrease in stored energy. These results were unlike the pathological elastase model where decreases in biaxial stretch were found along with increases in diameter, biaxial stress, and biaxial stiffness. ATAs from Tgfb1+/- and Tgfb3+/-, on the other hand, had few mechanical differences when compared to wild-type controls. Although aortopathy generally occurs later in development, our findings reveal that in 4-to-6 month-old animals, only Tgfb2+/- mice demonstrate a significant phenotype that fails to model ubiquitous elastolysis.
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Affiliation(s)
- Brooks A Lane
- Biomedical Engineering Program, University of South Carolina, Columbia, SC 29208 USA
| | - Mrinmay Chakrabarti
- Cell Biology and Anatomy Department, University of South Carolina School of Medicine, Columbia, SC 29208, USA
| | - Jacopo Ferruzzi
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Mohamad Azhar
- Cell Biology and Anatomy Department, University of South Carolina School of Medicine, Columbia, SC 29208, USA; William Jennings Bryan Dorn VA Medical Center, Columbia, SC 29209, USA
| | - John F Eberth
- Biomedical Engineering Program, University of South Carolina, Columbia, SC 29208 USA; Cell Biology and Anatomy Department, University of South Carolina School of Medicine, Columbia, SC 29208, USA.
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27
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Farra YM, Matz J, Ramkhelawon B, Oakes JM, Bellini C. Structural and functional remodeling of the female Apoe-/- mouse aorta due to chronic cigarette smoke exposure. Am J Physiol Heart Circ Physiol 2021; 320:H2270-H2282. [PMID: 33834870 DOI: 10.1152/ajpheart.00893.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Despite a decline in popularity over the past several decades, cigarette smoking remains a leading cause of cardiovascular morbidity and mortality. Yet, the effects of cigarette smoking on vascular structure and function are largely unknown. To evaluate changes in the mechanical properties of the aorta that occur with chronic smoking, we exposed female apolipoprotein E-deficient mice to mainstream cigarette smoke daily for 24 wk, with room air as control. By the time of euthanasia, cigarette-exposed mice had lower body mass but experienced larger systolic/diastolic blood pressure when compared with controls. Smoking was associated with significant wall thickening, reduced axial stretch, and circumferential material softening of the aorta. Although this contributed to maintaining intrinsic tissue stiffness at control levels despite larger pressure loads, the structural stiffness became significantly larger. Furthermore, the aorta from cigarette-exposed mice exhibited decreased ability to store elastic energy and augment diastolic blood flow. Histological analysis revealed a region-dependent increase in the cross-sectional area due to smoking. Increased smooth muscle and extracellular matrix content led to medial thickening in the ascending aorta, whereas collagen deposition increased the thickness of the descending thoracic and abdominal aorta. Atherosclerotic lesions were larger in exposed vessels and featured a necrotic core overlaid by a thinned fibrous cap and macrophage infiltration, consistent with a vulnerable phenotype. Collectively, our data indicate that cigarette smoking decreases the mechanical functionality of the aorta, inflicts morphometric alterations to distinct segments of the aorta, and accelerates the progression of atherosclerosis.NEW & NOTEWORTHY We studied the effects of chronic cigarette smoking on the structure and function of the aorta in a mouse model of nose-only aerosol inhalation. Our data indicated that exposure to cigarette smoke impairs vascular function by reducing the ability of the aorta to store elastic energy and by decreasing aortic distensibility. Combined with a more vulnerable atherosclerotic phenotype, these findings reveal the biomechanical mechanisms that support the development of cardiovascular disease due to cigarette smoking.
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Affiliation(s)
- Yasmeen M Farra
- Department of Bioengineering, Northeastern University, Boston, Massachusetts
| | - Jacqueline Matz
- Department of Bioengineering, Northeastern University, Boston, Massachusetts
| | - Bhama Ramkhelawon
- Division of Vascular Surgery, Department of Surgery, New York University Langone Health, New York City, New York.,Department of Cell Biology, New York University Langone Health, New York City, New York
| | - Jessica M Oakes
- Department of Bioengineering, Northeastern University, Boston, Massachusetts
| | - Chiara Bellini
- Department of Bioengineering, Northeastern University, Boston, Massachusetts
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28
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Pavey SN, Cocciolone AJ, Marty AG, Ismail HN, Hawes JZ, Wagenseil JE. Pentagalloyl glucose (PGG) partially prevents arterial mechanical changes due to elastin degradation. EXPERIMENTAL MECHANICS 2021; 61:41-51. [PMID: 33746235 PMCID: PMC7968080 DOI: 10.1007/s11340-020-00625-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
BACKGROUND Elastic fibers are composed primarily of the protein elastin and they provide reversible elasticity to the large arteries. Degradation of elastic fibers is a common histopathology in aortic aneurysms. Pentagalloyl glucose (PGG) has been shown to bind elastin and stabilize elastic fibers in some in vitro studies and in vivo models of abdominal aortic aneurysms, however its effects on native arteries are not well described. OBJECTIVE Perform detailed studies of the biomechanical effects of PGG on native arteries and the preventative capabilities of PGG for elastin degraded arteries. METHODS We treated mouse carotid arteries with PGG, elastase (ELA), and PGG+ELA and compared the wall structure, solid mechanics, and fluid transport properties to untreated (UNT) arteries. RESULTS We found that PGG alone decreased compliance compared to UNT arteries, but did not affect any other structural or biomechanical measures. Mild (30 sec) ELA treatment caused collapse and fragmentation of the elastic lamellae, plastic deformation, decreased compliance, increased modulus, and increased hydraulic conductance of the arterial wall compared to UNT. PGG+ELA treatment partially protected from all of these changes, in particular the plastic deformation. PGG mechanical protection varied considerably across PGG+ELA samples and appeared to correlate with the structural changes. CONCLUSIONS Our results provide important considerations for the effects of PGG on native arteries and a baseline for further biomechanical studies on preventative elastic fiber stabilization.
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Affiliation(s)
- S N Pavey
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO
| | - A J Cocciolone
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO
| | - A Gutierrez Marty
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO
| | - H N Ismail
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO
| | - J Z Hawes
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO
| | - J E Wagenseil
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO
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29
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Jadidi M, Razian SA, Habibnezhad M, Anttila E, Kamenskiy A. Mechanical, structural, and physiologic differences in human elastic and muscular arteries of different ages: Comparison of the descending thoracic aorta to the superficial femoral artery. Acta Biomater 2021; 119:268-283. [PMID: 33127484 PMCID: PMC7738395 DOI: 10.1016/j.actbio.2020.10.035] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/28/2020] [Accepted: 10/22/2020] [Indexed: 12/23/2022]
Abstract
Elastic and muscular arteries differ in structure, function, and mechanical properties, and may adapt differently to aging. We compared the descending thoracic aortas (TA) and the superficial femoral arteries (SFA) of 27 tissue donors (average 41±18 years, range 13-73 years) using planar biaxial testing, constitutive modeling, and bidirectional histology. Both TAs and SFAs increased in size with age, with the outer radius increasing more than the inner radius, but the TAs thickened 6-fold and widened 3-fold faster than the SFAs. The circumferential opening angle did not change in the TA, but increased 2.4-fold in the SFA. Young TAs were relatively isotropic, but the anisotropy increased with age due to longitudinal stiffening. SFAs were 51% more compliant longitudinally irrespective of age. Older TAs and SFAs were stiffer, but the SFA stiffened 5.6-fold faster circumferentially than the TA. Physiologic stresses decreased with age in both arteries, with greater changes occurring longitudinally. TAs had larger circumferential, but smaller longitudinal stresses than the SFAs, larger cardiac cycle stretch, 36% lower circumferential stiffness, and 8-fold more elastic energy available for pulsation. TAs contained elastin sheets separated by smooth muscle cells (SMCs), collagen, and glycosaminoglycans, while the SFAs had SMCs, collagen, and longitudinal elastic fibers. With age, densities of elastin and SMCs decreased, collagen remained constant due to medial thickening, and the glycosaminoglycans increased. Elastic and muscular arteries demonstrate different morphological, mechanical, physiologic, and structural characteristics and adapt differently to aging. While the aortas remodel to preserve the Windkessel function, the SFAs maintain higher longitudinal compliance.
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Affiliation(s)
- Majid Jadidi
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, USA
| | | | - Mahmoud Habibnezhad
- Department of Computer Science, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Eric Anttila
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Alexey Kamenskiy
- Department of Biomechanics, University of Nebraska Omaha, Omaha, NE, USA.
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30
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Weiss D, Cavinato C, Gray A, Ramachandra AB, Avril S, Humphrey JD, Latorre M. Mechanics-driven mechanobiological mechanisms of arterial tortuosity. SCIENCE ADVANCES 2020; 6:6/49/eabd3574. [PMID: 33277255 PMCID: PMC7821897 DOI: 10.1126/sciadv.abd3574] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/22/2020] [Indexed: 05/04/2023]
Abstract
Arterial tortuosity manifests in many conditions, including hypertension, genetic mutations predisposing to thoracic aortopathy, and vascular aging. Despite evidence that tortuosity disrupts efficient blood flow and that it may be an important clinical biomarker, underlying mechanisms remain poorly understood but are widely appreciated to be largely biomechanical. Many previous studies suggested that tortuosity may arise via an elastic structural buckling instability, but the novel experimental-computational approach used here suggests that tortuosity arises from mechanosensitive, cell-mediated responses to local aberrations in the microstructural integrity of the arterial wall. In particular, computations informed by multimodality imaging show that aberrations in elastic fiber integrity, collagen alignment, and collagen turnover can lead to a progressive loss of structural stability that entrenches during the development of tortuosity. Interpreted in this way, microstructural defects or irregularities of the arterial wall initiate the condition and hypertension is a confounding factor.
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Affiliation(s)
- Dar Weiss
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Cristina Cavinato
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Authia Gray
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | | | - Stephane Avril
- Mines Saint-Etienne, Centre CIS, INSERM, U 1059 Sainbiose University of Lyon, Univ Jean Monnet, Saint-Etienne, France
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA.
| | - Marcos Latorre
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
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31
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Latorre M, Humphrey JD. Numerical knockouts-In silico assessment of factors predisposing to thoracic aortic aneurysms. PLoS Comput Biol 2020; 16:e1008273. [PMID: 33079926 PMCID: PMC7598929 DOI: 10.1371/journal.pcbi.1008273] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 10/30/2020] [Accepted: 08/19/2020] [Indexed: 02/06/2023] Open
Abstract
Myriad risk factors–including uncontrolled hypertension, aging, and diverse genetic mutations–contribute to the development and enlargement of thoracic aortic aneurysms. Detailed analyses of clinical data and longitudinal studies of murine models continue to provide insight into the natural history of these potentially lethal conditions. Yet, because of the co-existence of multiple risk factors in most cases, it has been difficult to isolate individual effects of the many different factors or to understand how they act in combination. In this paper, we use a data-informed computational model of the initiation and progression of thoracic aortic aneurysms to contrast key predisposing risk factors both in isolation and in combination; these factors include localized losses of elastic fiber integrity, aberrant collagen remodeling, reduced smooth muscle contractility, and dysfunctional mechanosensing or mechanoregulation of extracellular matrix along with superimposed hypertension and aortic aging. In most cases, mild-to-severe localized losses in cellular function or matrix integrity give rise to varying degrees of local dilatations of the thoracic aorta, with enlargement typically exacerbated in cases wherein predisposing risk factors co-exist. The simulations suggest, for the first time, that effects of compromised smooth muscle contractility are more important in terms of dysfunctional mechanosensing and mechanoregulation of matrix than in vessel-level control of diameter and, furthermore, that dysfunctional mechanobiological control can yield lesions comparable to those in cases of compromised elastic fiber integrity. Particularly concerning, therefore, is that loss of constituents such as fibrillin-1, as in Marfan syndrome, can compromise both elastic fiber integrity and mechanosensing. Aneurysms are local dilatations of the arterial wall that are responsible for significant disability and death. Detailed analyses of clinical data continue to provide insight into the natural history of these potentially lethal conditions, with myriad risk factors–including uncontrolled hypertension, aging, and diverse genetic mutations–contributing to their development and enlargement. Yet, because of the co-existence of these risk factors in most cases, it has been difficult to isolate individual effects or to understand how they act in combination. In this paper, we use a computational model of the initiation and progression of thoracic aortic aneurysms to contrast key predisposing factors both in isolation and in combination as well as with superimposed hypertension and aging. The present study recovers many findings from mouse models but with new and important observations that promise to guide in vivo and ex vivo studies as we seek to understand and eventually better treat these complex, multi-factorial lesions, with data-informed patient-specific computations eventually the way forward.
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Affiliation(s)
- M. Latorre
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States of America
| | - J. D. Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States of America
- * E-mail:
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32
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Nandadasa S, Szafron JM, Pathak V, Murtada SI, Kraft CM, O'Donnell A, Norvik C, Hughes C, Caterson B, Domowicz MS, Schwartz NB, Tran-Lundmark K, Veigl M, Sedwick D, Philipson EH, Humphrey JD, Apte SS. Vascular dimorphism ensured by regulated proteoglycan dynamics favors rapid umbilical artery closure at birth. eLife 2020; 9:e60683. [PMID: 32909945 PMCID: PMC7529456 DOI: 10.7554/elife.60683] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/09/2020] [Indexed: 01/29/2023] Open
Abstract
The umbilical artery lumen closes rapidly at birth, preventing neonatal blood loss, whereas the umbilical vein remains patent longer. Here, analysis of umbilical cords from humans and other mammals identified differential arterial-venous proteoglycan dynamics as a determinant of these contrasting vascular responses. The umbilical artery, but not the vein, has an inner layer enriched in the hydrated proteoglycan aggrecan, external to which lie contraction-primed smooth muscle cells (SMC). At birth, SMC contraction drives inner layer buckling and centripetal displacement to occlude the arterial lumen, a mechanism revealed by biomechanical observations and confirmed by computational analyses. This vascular dimorphism arises from spatially regulated proteoglycan expression and breakdown. Mice lacking aggrecan or the metalloprotease ADAMTS1, which degrades proteoglycans, demonstrate their opposing roles in umbilical vascular dimorphism, including effects on SMC differentiation. Umbilical vessel dimorphism is conserved in mammals, suggesting that differential proteoglycan dynamics and inner layer buckling were positively selected during evolution.
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Affiliation(s)
- Sumeda Nandadasa
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research InstituteClevelandUnited States
| | - Jason M Szafron
- Department of Biomedical Engineering, Yale UniversityNew HavenUnited States
| | - Vai Pathak
- Case Comprehensive Cancer Center, Case Western Reserve UniversityClevelandUnited States
| | - Sae-Il Murtada
- Department of Biomedical Engineering, Yale UniversityNew HavenUnited States
| | - Caroline M Kraft
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research InstituteClevelandUnited States
| | - Anna O'Donnell
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research InstituteClevelandUnited States
| | - Christian Norvik
- Department of Experimental Medical Science and Wallenberg Center for Molecular Medicine, Lund UniversityLundSweden
| | - Clare Hughes
- The Sir Martin Evans Building, School of Biosciences, Cardiff UniversityCardiffUnited Kingdom
| | - Bruce Caterson
- The Sir Martin Evans Building, School of Biosciences, Cardiff UniversityCardiffUnited Kingdom
| | | | - Nancy B Schwartz
- Department of Pediatrics, University of ChicagoChicagoUnited States
| | - Karin Tran-Lundmark
- Department of Experimental Medical Science and Wallenberg Center for Molecular Medicine, Lund UniversityLundSweden
| | - Martina Veigl
- Case Comprehensive Cancer Center, Case Western Reserve UniversityClevelandUnited States
- Department of Medicine, Case Western Reserve UniversityClevelandUnited States
| | - David Sedwick
- Department of Medicine, Case Western Reserve UniversityClevelandUnited States
| | - Elliot H Philipson
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research InstituteClevelandUnited States
- The Women's Health Institute, Department of Obstetrics and Gynecology, Cleveland ClinicClevelandUnited States
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale UniversityNew HavenUnited States
| | - Suneel S Apte
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research InstituteClevelandUnited States
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Spronck B, Ferruzzi J, Bellini C, Caulk AW, Murtada SI, Humphrey JD. Aortic remodeling is modest and sex-independent in mice when hypertension is superimposed on aging. J Hypertens 2020; 38:1312-1321. [PMID: 32068640 PMCID: PMC7611466 DOI: 10.1097/hjh.0000000000002400] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVES Increased central artery stiffness associates with cardiovascular disease. Among other factors, hypertension and aging are strong contributors to central artery stiffening, yet it has been difficult to separate their effects. Herein, we study isolated and combined effects of hypertension and aging on central artery remodeling in multiple mouse models as a function of sex. METHODS We biomechanically phenotyped the aorta as a function of two different methods of inducing hypertension [infusion of angiotensin II (AngII) or combining a high salt diet with inhibition of endothelial-derived nitric oxide synthase using L-NAME] in male and female wild-type and fibulin-5 null mice, the latter of which models aspects of aortic aging. RESULTS Despite increasing blood pressure similarly, salt + L-NAME led to adaptive and maladaptive remodeling in the abdominal and thoracic aorta, respectively, whereas AngII caused luminal dilatation but little remodeling of the wall. Importantly, effects of aging were more dramatic than those resulting from induced hypertension and, consequently, superimposing hypertension on aging led to modest additional changes in luminal radius and wall thickness, though wall stress and stiffness increased mainly because of the elevated pressure. CONCLUSION Our results suggest that effects of hypertension on aortic remodeling are modest when superimposed on aging in mice, largely independent of sex. These findings are consistent with general observations in humans and in spontaneously hypertensive rats, though separated here for the first time in a rodent model characterized by a severe loss of elastic fiber integrity similar to that found in the aged human aorta.
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Affiliation(s)
- Bart Spronck
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
- Department of Biomedical Engineering, Maastricht University, Maastricht, The Netherlands
| | - Jacopo Ferruzzi
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
| | - Chiara Bellini
- Department of Bioengineering, Northeastern University, Boston, Massachusetts
| | - Alexander W Caulk
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
| | - Sae-Il Murtada
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
- Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, Connecticut, USA
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34
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Murtada SI, Kawamura Y, Caulk AW, Ahmadzadeh H, Mikush N, Zimmerman K, Kavanagh D, Weiss D, Latorre M, Zhuang ZW, Shadel GS, Braddock DT, Humphrey JD. Paradoxical aortic stiffening and subsequent cardiac dysfunction in Hutchinson-Gilford progeria syndrome. J R Soc Interface 2020; 17:20200066. [PMID: 32453981 DOI: 10.1098/rsif.2020.0066] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is an ultra-rare disorder with devastating sequelae resulting in early death, presently thought to stem primarily from cardiovascular events. We analyse novel longitudinal cardiovascular data from a mouse model of HGPS (LmnaG609G/G609G) using allometric scaling, biomechanical phenotyping, and advanced computational modelling and show that late-stage diastolic dysfunction, with preserved systolic function, emerges with an increase in the pulse wave velocity and an associated loss of aortic function, independent of sex. Specifically, there is a dramatic late-stage loss of smooth muscle function and cells and an excessive accumulation of proteoglycans along the aorta, which result in a loss of biomechanical function (contractility and elastic energy storage) and a marked structural stiffening despite a distinctly low intrinsic material stiffness that is consistent with the lack of functional lamin A. Importantly, the vascular function appears to arise normally from the low-stress environment of development, only to succumb progressively to pressure-related effects of the lamin A mutation and become extreme in the peri-morbid period. Because the dramatic life-threatening aortic phenotype manifests during the last third of life there may be a therapeutic window in maturity that could alleviate concerns with therapies administered during early periods of arterial development.
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Affiliation(s)
- S-I Murtada
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Y Kawamura
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - A W Caulk
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - H Ahmadzadeh
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - N Mikush
- Translational Research Imaging Center, Yale School of Medicine, New Haven, CT, USA
| | - K Zimmerman
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - D Kavanagh
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - D Weiss
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - M Latorre
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Z W Zhuang
- Section of Cardiovascular Medicine, Yale School of Medicine, New Haven, CT, USA
| | - G S Shadel
- Molecular and Cellular Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - D T Braddock
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - J D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA.,Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA
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35
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Caulk AW, Humphrey JD, Murtada SI. Fundamental Roles of Axial Stretch in Isometric and Isobaric Evaluations of Vascular Contractility. J Biomech Eng 2020; 141:2718205. [PMID: 30516238 DOI: 10.1115/1.4042171] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Indexed: 12/22/2022]
Abstract
Vascular smooth muscle cells (VSMCs) can regulate arterial mechanics via contractile activity in response to changing mechanical and chemical signals. Contractility is traditionally evaluated via uniaxial isometric testing of isolated rings despite the in vivo environment being very different. Most blood vessels maintain a locally preferred value of in vivo axial stretch while subjected to changes in distending pressure, but both of these phenomena are obscured in uniaxial isometric testing. Few studies have rigorously analyzed the role of in vivo loading conditions in smooth muscle function. Thus, we evaluated effects of uniaxial versus biaxial deformations on smooth muscle contractility by stimulating two regions of the mouse aorta with different vasoconstrictors using one of three testing protocols: (i) uniaxial isometric testing, (ii) biaxial isometric testing, and (iii) axially isometric plus isobaric testing. Comparison of methods (i) and (ii) revealed increased sensitivity and contractile capacity to potassium chloride and phenylephrine (PE) with biaxial isometric testing, and comparison of methods (ii) and (iii) revealed a further increase in contractile capacity with isometric plus isobaric testing. Importantly, regional differences in estimated in vivo axial stretch suggest locally distinct optimal biaxial configurations for achieving maximal smooth muscle contraction, which can only be revealed with biaxial testing. Such differences highlight the importance of considering in vivo loading and geometric configurations when evaluating smooth muscle function. Given the physiologic relevance of axial extension and luminal pressurization, we submit that, when possible, axially isometric plus isobaric testing should be employed to evaluate vascular smooth muscle contractile function.
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Affiliation(s)
- Alexander W Caulk
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520
| | - Jay D Humphrey
- Fellow ASME Department of Biomedical Engineering, Yale University, New Haven, CT 06520.,Vascular Biology and Therapeutics Program, Yale University, New Haven, CT 06520
| | - Sae-Il Murtada
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT 06520 e-mail:
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36
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Caulk AW, Janes KA. Robust latent-variable interpretation of in vivo regression models by nested resampling. Sci Rep 2019; 9:19671. [PMID: 31873087 PMCID: PMC6928252 DOI: 10.1038/s41598-019-55796-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 12/03/2019] [Indexed: 11/21/2022] Open
Abstract
Simple multilinear methods, such as partial least squares regression (PLSR), are effective at interrelating dynamic, multivariate datasets of cell-molecular biology through high-dimensional arrays. However, data collected in vivo are more difficult, because animal-to-animal variability is often high, and each time-point measured is usually a terminal endpoint for that animal. Observations are further complicated by the nesting of cells within tissues or tissue sections, which themselves are nested within animals. Here, we introduce principled resampling strategies that preserve the tissue-animal hierarchy of individual replicates and compute the uncertainty of multidimensional decompositions applied to global averages. Using molecular-phenotypic data from the mouse aorta and colon, we find that interpretation of decomposed latent variables (LVs) changes when PLSR models are resampled. Lagging LVs, which statistically improve global-average models, are unstable in resampled iterations that preserve nesting relationships, arguing that these LVs should not be mined for biological insight. Interestingly, resampling is less discriminatory for multidimensional regressions of in vitro data, where replicate-to-replicate variance is sufficiently low. Our work illustrates the challenges and opportunities in translating systems-biology approaches from cultured cells to living organisms. Nested resampling adds a straightforward quality-control step for interpreting the robustness of in vivo regression models.
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Affiliation(s)
- Alexander W Caulk
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06510, USA
| | - Kevin A Janes
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, 22908, USA.
- Department of Biochemistry & Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA.
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37
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Lin CJ, Staiculescu MC, Hawes JZ, Cocciolone AJ, Hunkins BM, Roth RA, Lin CY, Mecham RP, Wagenseil JE. Heterogeneous Cellular Contributions to Elastic Laminae Formation in Arterial Wall Development. Circ Res 2019; 125:1006-1018. [PMID: 31590613 DOI: 10.1161/circresaha.119.315348] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
RATIONALE Elastin is an important ECM (extracellular matrix) protein in large and small arteries. Vascular smooth muscle cells (SMCs) produce the layered elastic laminae found in elastic arteries but synthesize little elastin in muscular arteries. However, muscular arteries have a well-defined internal elastic lamina (IEL) that separates endothelial cells (ECs) from SMCs. The extent to which ECs contribute elastin to the IEL is unknown. OBJECTIVE To use targeted elastin (Eln) deletion in mice to explore the relative contributions of SMCs and ECs to elastic laminae formation in different arteries. METHODS AND RESULTS We used SMC- and EC-specific Cre recombinase transgenes with a novel floxed Eln allele to focus gene inactivation in mice. Inactivation of Eln in SMCs using Sm22aCre resulted in depletion of elastic laminae in the arterial wall with the exception of the IEL and SMC clusters in the outer media near the adventitia. Inactivation of elastin in ECs using Tie2Cre or Cdh5Cre resulted in normal medial elastin and a typical IEL in elastic arteries. In contrast, the IEL was absent or severely disrupted in muscular arteries. Interruptions in the IEL resulted in neointimal formation in the ascending aorta but not in muscular arteries. CONCLUSIONS Combined with lineage-specific fate mapping systems, our knockout results document an unexpected heterogeneity in vascular cells that produce the elastic laminae. SMCs and ECs can independently form an IEL in most elastic arteries, whereas ECs are the major source of elastin for the IEL in muscular and resistance arteries. Neointimal formation at IEL disruptions in the ascending aorta confirms that the IEL is a critical physical barrier between SMCs and ECs in the large elastic arteries. Our studies provide new information about how SMCs and ECs contribute elastin to the arterial wall and how local elastic laminae defects may contribute to cardiovascular disease.
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Affiliation(s)
- Chien-Jung Lin
- From the Department of Cell Biology and Physiology (C.-J.L., B.M.H., R.A.R., R.P.M.).,Department of Internal Medicine, Cardiovascular Division (C.-J.L.)
| | - Marius C Staiculescu
- Department of Mechanical Engineering and Materials Science (M.C.S., J.Z.H., J.E.W.)
| | - Jie Z Hawes
- Department of Mechanical Engineering and Materials Science (M.C.S., J.Z.H., J.E.W.)
| | - Austin J Cocciolone
- Departments of Biomedical Engineering (A.J.C.), Washington University, St. Louis, MO
| | - Bridget M Hunkins
- From the Department of Cell Biology and Physiology (C.-J.L., B.M.H., R.A.R., R.P.M.)
| | - Robyn A Roth
- From the Department of Cell Biology and Physiology (C.-J.L., B.M.H., R.A.R., R.P.M.)
| | - Chieh-Yu Lin
- Pathology and Immunology (C.-Y.L.), Washington University, St. Louis, MO
| | - Robert P Mecham
- From the Department of Cell Biology and Physiology (C.-J.L., B.M.H., R.A.R., R.P.M.)
| | - Jessica E Wagenseil
- Department of Mechanical Engineering and Materials Science (M.C.S., J.Z.H., J.E.W.)
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38
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Stoka KV, Maedeker JA, Bennett L, Bhayani SA, Gardner WS, Procknow JD, Cocciolone AJ, Walji TA, Craft CS, Wagenseil JE. Effects of Increased Arterial Stiffness on Atherosclerotic Plaque Amounts. J Biomech Eng 2019; 140:2672193. [PMID: 29392300 DOI: 10.1115/1.4039175] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Indexed: 12/21/2022]
Abstract
Increased arterial stiffness is associated with atherosclerosis in humans, but there have been limited animal studies investigating the relationship between these factors. We bred elastin wildtype (Eln+/+) and heterozygous (Eln+/-) mice to apolipoprotein E wildtype (Apoe+/+) and knockout (Apoe-/-) mice and fed them normal diet (ND) or Western diet (WD) for 12 weeks. Eln+/- mice have increased arterial stiffness. Apoe-/- mice develop atherosclerosis on ND that is accelerated by WD. It has been reported that Apoe-/- mice have increased arterial stiffness and that the increased stiffness may play a role in atherosclerotic plaque progression. We found that Eln+/+Apoe-/- arterial stiffness is similar to Eln+/+Apoe+/+ mice at physiologic pressures, suggesting that changes in stiffness do not play a role in atherosclerotic plaque progression in Apoe-/- mice. We found that Eln+/-Apoe-/- mice have increased structural arterial stiffness compared to Eln+/+Apoe-/- mice, but they only have increased amounts of ascending aortic plaque on ND, not WD. The results suggest a change in atherosclerosis progression but not end stage disease in Eln+/-Apoe-/- mice due to increased arterial stiffness. Possible contributing factors include increased blood pressure and changes in circulating levels of interleukin-6 (IL6) and transforming growth factor beta 1 (TGF-β1) that are also associated with Eln+/- genotype.
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Affiliation(s)
- Kellie V Stoka
- Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130
| | - Justine A Maedeker
- Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130
| | - Lisa Bennett
- Department of Biomedical Engineering, Saint Louis University, St. Louis, MO 63130
| | - Siddharth A Bhayani
- Department of Biomedical Engineering, Saint Louis University, St. Louis, MO 63130
| | - William S Gardner
- Department of Biomedical Engineering, Saint Louis University, St. Louis, MO 63130
| | - Jesse D Procknow
- Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130
| | - Austin J Cocciolone
- Department of Mechanical Engineering and Materials Science, Washington University, , St. Louis, MO 63130
| | - Tezin A Walji
- Department of Cell Biology and Physiology, Washington University, St. Louis, MO 63130
| | - Clarissa S Craft
- Department of Cell Biology and Physiology, Washington University, St. Louis, MO 63130
| | - Jessica E Wagenseil
- Department of Mechanical Engineering and Materials Science, Washington University, , St. Louis, MO 63130 e-mail:
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39
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Best CA, Szafron JM, Rocco KA, Zbinden J, Dean EW, Maxfield MW, Kurobe H, Tara S, Bagi PS, Udelsman BV, Khosravi R, Yi T, Shinoka T, Humphrey JD, Breuer CK. Differential outcomes of venous and arterial tissue engineered vascular grafts highlight the importance of coupling long-term implantation studies with computational modeling. Acta Biomater 2019; 94:183-194. [PMID: 31200116 PMCID: PMC6819998 DOI: 10.1016/j.actbio.2019.05.063] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/07/2019] [Accepted: 05/24/2019] [Indexed: 12/13/2022]
Abstract
Electrospinning is commonly used to generate polymeric scaffolds for tissue engineering. Using this approach, we developed a small-diameter tissue engineered vascular graft (TEVG) composed of poly-ε-caprolactone-co-l-lactic acid (PCLA) fibers and longitudinally assessed its performance within both the venous and arterial circulations of immunodeficient (SCID/bg) mice. Based on in vitro analysis demonstrating complete loss of graft strength by 12 weeks, we evaluated neovessel formation in vivo over 6-, 12- and 24-week periods. Mid-term observations indicated physiologic graft function, characterized by 100% patency and luminal matching with adjoining native vessel in both the venous and arterial circulations. An active and robust remodeling process was characterized by a confluent endothelial cell monolayer, macrophage infiltrate, and extracellular matrix deposition and remodeling. Long-term follow-up of venous TEVGs at 24 weeks revealed viable neovessel formation beyond graft degradation when implanted in this high flow, low-pressure environment. Arterial TEVGs experienced catastrophic graft failure due to aneurysmal dilatation and rupture after 14 weeks. Scaffold parameters such as porosity, fiber diameter, and degradation rate informed a previously described computational model of vascular growth and remodeling, and simulations predicted the gross differential performance of the venous and arterial TEVGs over the 24-week time course. Taken together, these results highlight the requirement for in vivo implantation studies to extend past the critical time period of polymer degradation, the importance of differential neotissue deposition relative to the mechanical (pressure) environment, and further support the utility of predictive modeling in the design, use, and evaluation of TEVGs in vivo. STATEMENT OF SIGNIFICANCE: Herein, we apply a biodegradable electrospun vascular graft to the arterial and venous circulations of the mouse and follow recipients beyond the point of polymer degradation. While venous implants formed viable neovessels, arterial grafts experienced catastrophic rupture due to aneurysmal dilation. We then inform a previously developed computational model of tissue engineered vascular graft growth and remodeling with parameters specific to the electrospun scaffolds utilized in this study. Remarkably, model simulations predict the differential performance of the venous and arterial constructs over 24 weeks. We conclude that computational simulations should inform the rational selection of scaffold parameters to fabricate tissue engineered vascular grafts that must be followed in vivo over time courses extending beyond polymer degradation.
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Affiliation(s)
- Cameron A Best
- Center for Regenerative Medicine, Tissue Engineering Program, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States; Biomedical Sciences Graduate Program, The Ohio State University College of Medicine, Columbus, OH, United States.
| | - Jason M Szafron
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States
| | | | - Jacob Zbinden
- Center for Regenerative Medicine, Tissue Engineering Program, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States; Biomedical Engineering Graduate Program, The Ohio State University College of Engineering, Columbus, OH, United States
| | - Ethan W Dean
- Department of Orthopaedic Surgery, University of Florida, Gainesville, FL, United States
| | - Mark W Maxfield
- Department of Thoracic Surgery, University of Massachusetts Memorial Medical Center, Worcester, MA, United States
| | - Hirotsugu Kurobe
- Department of Cardiovascular Surgery, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Shuhei Tara
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| | - Paul S Bagi
- Department of Orthopaedic Surgery, Yale-New Haven Hospital, New Haven, CT, United States
| | - Brooks V Udelsman
- Department of Surgery, Massachusetts General Hospital, Boston, MA, United States
| | - Ramak Khosravi
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States
| | - Tai Yi
- Center for Regenerative Medicine, Tissue Engineering Program, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States
| | - Toshiharu Shinoka
- Center for Regenerative Medicine, Tissue Engineering Program, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States; Department of Cardiac Surgery, Nationwide Children's Hospital, Columbus, OH, United States
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States; Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, United States
| | - Christopher K Breuer
- Center for Regenerative Medicine, Tissue Engineering Program, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States; Department of Surgery, Nationwide Children's Hospital, Columbus, OH, United States
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40
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Gabriela Espinosa M, Catalin Staiculescu M, Kim J, Marin E, Wagenseil JE. Elastic Fibers and Large Artery Mechanics in Animal Models of Development and Disease. J Biomech Eng 2019; 140:2666245. [PMID: 29222533 DOI: 10.1115/1.4038704] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Indexed: 12/21/2022]
Abstract
Development of a closed circulatory system requires that large arteries adapt to the mechanical demands of high, pulsatile pressure. Elastin and collagen uniquely address these design criteria in the low and high stress regimes, resulting in a nonlinear mechanical response. Elastin is the core component of elastic fibers, which provide the artery wall with energy storage and recoil. The integrity of the elastic fiber network is affected by component insufficiency or disorganization, leading to an array of vascular pathologies and compromised mechanical behavior. In this review, we discuss how elastic fibers are formed and how they adapt in development and disease. We discuss elastic fiber contributions to arterial mechanical behavior and remodeling. We primarily present data from mouse models with elastic fiber deficiencies, but suggest that alternate small animal models may have unique experimental advantages and the potential to provide new insights. Advanced ultrastructural and biomechanical data are constantly being used to update computational models of arterial mechanics. We discuss the progression from early phenomenological models to microstructurally motivated strain energy functions for both collagen and elastic fiber networks. Although many current models individually account for arterial adaptation, complex geometries, and fluid-solid interactions (FSIs), future models will need to include an even greater number of factors and interactions in the complex system. Among these factors, we identify the need to revisit the role of time dependence and axial growth and remodeling in large artery mechanics, especially in cardiovascular diseases that affect the mechanical integrity of the elastic fibers.
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Affiliation(s)
| | | | - Jungsil Kim
- Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130
| | - Eric Marin
- Department of Biomedical Engineering, Saint Louis University, St. Louis, MO 63103
| | - Jessica E Wagenseil
- Department of Mechanical Engineering and Materials Science, Washington University, , St. Louis, MO 63130 e-mail:
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Oh YS, Berkowitz DE, Cohen RA, Figueroa CA, Harrison DG, Humphrey JD, Larson DF, Leopold JA, Mecham RP, Ruiz-Opazo N, Santhanam L, Seta F, Shyy JYJ, Sun Z, Tsao PS, Wagenseil JE, Galis ZS. A Special Report on the NHLBI Initiative to Study Cellular and Molecular Mechanisms of Arterial Stiffness and Its Association With Hypertension. Circ Res 2019; 121:1216-1218. [PMID: 29122942 DOI: 10.1161/circresaha.117.311703] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Young S Oh
- See the Online Supplement for the author affiliations.
| | | | | | | | | | | | | | | | | | | | | | | | - John Y J Shyy
- See the Online Supplement for the author affiliations
| | - Zhongjie Sun
- See the Online Supplement for the author affiliations
| | - Philip S Tsao
- See the Online Supplement for the author affiliations
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42
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Elastic fibers and biomechanics of the aorta: Insights from mouse studies. Matrix Biol 2019; 85-86:160-172. [PMID: 30880160 DOI: 10.1016/j.matbio.2019.03.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 02/28/2019] [Accepted: 03/04/2019] [Indexed: 12/14/2022]
Abstract
Elastic fibers are major components of the extracellular matrix (ECM) in the aorta and support a life-long cycling of stretch and recoil. Elastic fibers are formed from mid-gestation throughout early postnatal development and the synthesis is regulated at multiple steps, including coacervation, deposition, cross-linking, and assembly of insoluble elastin onto microfibril scaffolds. To date, more than 30 molecules have been shown to associate with elastic fibers and some of them play a critical role in the formation and maintenance of elastic fibers in vivo. Because the aorta is subjected to high pressure from the left ventricle, elasticity of the aorta provides the Windkessel effect and maintains stable blood flow to distal organs throughout the cardiac cycle. Disruption of elastic fibers due to congenital defects, inflammation, or aging dramatically reduces aortic elasticity and affects overall vessel mechanics. Another important component in the aorta is the vascular smooth muscle cells (SMCs). Elastic fibers and SMCs alternate to create a highly organized medial layer within the aortic wall. The physical connections between elastic fibers and SMCs form the elastin-contractile units and maintain cytoskeletal organization and proper responses of SMCs to mechanical strain. In this review, we revisit the components of elastic fibers and their roles in elastogenesis and how a loss of each component affects biomechanics of the aorta. Finally, we discuss the significance of elastin-contractile units in the maintenance of SMC function based on knowledge obtained from mouse models of human disease.
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B Ramachandra A, Humphrey JD. Biomechanical characterization of murine pulmonary arteries. J Biomech 2019; 84:18-26. [PMID: 30598195 PMCID: PMC6361676 DOI: 10.1016/j.jbiomech.2018.12.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 11/11/2018] [Accepted: 12/05/2018] [Indexed: 12/20/2022]
Abstract
The biomechanical properties of the major pulmonary arteries play critical roles in normal physiology as well as in diverse pathophysiologies and clinical interventions. Importantly, advances in medical imaging enable simulations of pulmonary hemodynamics, but such models cannot reach their full potential until they are informed with region-specific material properties. In this paper, we present passive and active biaxial biomechanical data for the right and left main pulmonary arteries from wild-type mice. We also evaluate the suitability of a four-fiber family constitutive model as a descriptor of the passive behavior. Despite regional differences in size, the biaxial mechanical properties, including passive stiffness and elastic energy storage, the biaxial wall stresses at in vivo pressures, and the overall contractile capacity in response to smooth muscle cell stimulation under in vivo conditions are remarkably similar between the right and left branches. The proposed methods and results can serve as baseline protocols and measurements for future biaxial experiments on murine models of pulmonary pathologies, and the constitutive model can inform computational models of normal pulmonary growth and remodeling. Our use of consistent experimental protocols and data analyses can also facilitate comparative studies in health and disease across the systemic and pulmonary circulations as well as studies seeking to understand remodeling in surgeries such as the Fontan procedure, which involves different types of vessels.
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Affiliation(s)
- Abhay B Ramachandra
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States; Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, United States.
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Cuomo F, Ferruzzi J, Agarwal P, Li C, Zhuang ZW, Humphrey JD, Figueroa CA. Sex-dependent differences in central artery haemodynamics in normal and fibulin-5 deficient mice: implications for ageing. Proc Math Phys Eng Sci 2019; 475:20180076. [PMID: 30760948 PMCID: PMC6364598 DOI: 10.1098/rspa.2018.0076] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 11/26/2018] [Indexed: 12/17/2022] Open
Abstract
Mouse models provide unique opportunities to study vascular disease, but they demand increased experimental and computational resolution. We describe a workflow for combining in vivo and in vitro biomechanical data to build mouse-specific computational models of the central vasculature including regional variations in biaxial wall stiffness, thickness and perivascular support. These fluid-solid interaction models are informed by micro-computed tomography imaging and in vivo ultrasound and pressure measurements, and include mouse-specific inflow and outflow boundary conditions. Hence, the model can capture three-dimensional unsteady flows and pulse wave characteristics. The utility of this experimental-computational approach is illustrated by comparing central artery biomechanics in adult wild-type and fibulin-5 deficient mice, a model of early vascular ageing. Findings are also examined as a function of sex. Computational results compare well with measurements and data available in the literature and suggest that pulse wave velocity, a spatially integrated measure of arterial stiffness, does not reflect well the presence of regional differences in stiffening, particularly those manifested in male versus female mice. Modelling results are also useful for comparing quantities that are difficult to measure or infer experimentally, including local pulse pressures at the renal arteries and characteristics of the peripheral vascular bed that may differ with disease.
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Affiliation(s)
- Federica Cuomo
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Jacopo Ferruzzi
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Pradyumn Agarwal
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Chen Li
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Zhen W. Zhuang
- Translational Research Imaging Center, Yale University, New Haven, CT, USA
| | - Jay D. Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale University, New Haven, CT, USA
| | - C. Alberto Figueroa
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Surgery, University of Michigan, Ann Arbor, MI, USA
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Cocciolone AJ, Johnson E, Shao JY, Wagenseil JE. Elastic fiber fragmentation increases transmural hydraulic conductance and solute transport in mouse arteries. J Biomech Eng 2018; 141:2718211. [PMID: 30516242 DOI: 10.1115/1.4042173] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Indexed: 01/15/2023]
Abstract
Transmural advective transport of solute and fluid was investigated in mouse carotid arteries with either a genetic knockout of Fibulin-5 (Fbln5-/-) or treatment with elastase to determine the influence of a disrupted elastic fiber matrix on wall transport properties. Fibulin-5 is an important director of elastic fiber assembly. Arteries from Fbln5-/- mice have a loose, non-continuous elastic fiber network and were hypothesized to have reduced resistance to advective transport. Experiments were carried out ex vivo at physiological pressure and axial stretch. Hydraulic conductance (Lp ) was measured to be 4.99·10-6 ± 8.94·10-7, 3.18·-5 ± 1.13·10-5 (P < 0.01), and 3.57·10-5 ± 1.77·10-5 (P < 0.01) mm·s-1·mmHg-1 for wild-type, Fbln5-/-, and elastase-treated carotids, respectively. Solute fluxes of 4, 70, and 150 kDa FITC-dextran were statistically increased in Fbln5-/- compared to wild-type by a factor of 4, 22, and 3 respectively. 70 kDa FITC-dextran solute flux was similarly increased in elastase-treated carotids by a factor of 27. Solute uptake by Fbln5-/- carotids was decreased compared to wild-type for all investigated dextran sizes after 60 minutes of transmural transport. These changes in transport properties of elastic fiber compromised arteries have important implications for the kinetics of biomolecules and pharmaceuticals in arterial tissue following elastic fiber degradation due to aging or vascular disease.
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Affiliation(s)
| | - Elizabeth Johnson
- Mechanical Engineering and Materials Science, Washington University, St. Louis, MO, USA
| | - Jin-Yu Shao
- Mechanical Engineering and Materials Science, Washington University, St. Louis, MO, USA
| | - Jessica E Wagenseil
- Department of Mechanical Engineering and Materials Science, Washington University, One Brookings Dr., CB 1185, St. Louis, MO 63130
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Local variations in material and structural properties characterize murine thoracic aortic aneurysm mechanics. Biomech Model Mechanobiol 2018; 18:203-218. [PMID: 30251206 DOI: 10.1007/s10237-018-1077-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 09/14/2018] [Indexed: 12/18/2022]
Abstract
We recently developed an approach to characterize local nonlinear, anisotropic mechanical properties of murine arteries by combining biaxial extension-distension testing, panoramic digital image correlation, and an inverse method based on the principle of virtual power. This experimental-computational approach was illustrated for the normal murine abdominal aorta assuming uniform wall thickness. Here, however, we extend our prior approach by adding an optical coherence tomography (OCT) imaging system that permits local reconstructions of wall thickness. This multimodality approach is then used to characterize spatial variations of material and structural properties in ascending thoracic aortic aneurysms (aTAA) from two genetically modified mouse models (fibrillin-1 and fibulin-4 deficient) and to compare them with those from angiotensin II-infused apolipoprotein E-deficient and wild-type control ascending aortas. Local values of stored elastic energy and biaxial material stiffness, computed from spatial distributions of the best fit material parameters, varied significantly with circumferential position (inner vs. outer curvature, ventral vs. dorsal sides) across genotypes and treatments. Importantly, these data reveal an inverse relationship between material stiffness and wall thickness that underlies a general linear relationship between stiffness and wall stress across aTAAs. OCT images also revealed sites of advanced medial degeneration, which were captured by the inverse material characterization. Quantification of histological data further provided high-resolution local correlations among multiple mechanical metrics and wall microstructure. This is the first time that such structural defects and local properties have been characterized mechanically, which can better inform computational models of aortopathy that seek to predict where dissection or rupture may initiate.
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Jayyosi C, Lee N, Willcockson A, Nallasamy S, Mahendroo M, Myers K. The mechanical response of the mouse cervix to tensile cyclic loading in term and preterm pregnancy. Acta Biomater 2018; 78:308-319. [PMID: 30059802 PMCID: PMC6336396 DOI: 10.1016/j.actbio.2018.07.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 06/21/2018] [Accepted: 07/10/2018] [Indexed: 02/03/2023]
Abstract
A well-timed modification of both the collagen and elastic fiber network in the cervix during pregnancy accompanies the evolution of tissue mechanical parameters that are key to a successful pregnancy. Understanding of the cervical mechanical behaviour along normal and abnormal pregnancy is crucial to define the molecular events that regulate remodeling in term and preterm birth (PTB). In this study, we measured the mechanical response of mouse cervical tissue to a history of cyclic loading and quantified the tissue's ability to recover from small and large deformations. Assessments were made in nonpregnant, pregnant (gestation days 6, 12, 15 and 18) and mouse models of infection mediated PTB treated with lipopolysaccharide on gestation d15 (LPS treated) and hormone withdrawal mediated PTB on gestation d15 (RU486 treated). The current study uncovers the contributions of collagen and elastic fiber networks to the progressive change in mechanical function of the cervix through pregnancy. Premature cervical remodeling induced on gestation day 15 in the LPS infection model is characterized by distinct mechanical properties that are similar but not identical to mechanical properties at term ripening on day 18. Remodeling in the LPS infection model results in a weaker cervix, unable to withstand high loads. In contrast, the RU486 preterm model resembles the cyclic mechanical behaviour seen for term d18 cervix, where the extremely compliant tissue is able to withstand multiple cycles under large deformations without breaking. The distinct material responses to load-unload cycles in the two PTB models matches the differing microstructural changes in collagen and elastic fibers in these two models of preterm birth. Improved understanding of the impact of microstructural changes to mechanical performance of the cervix will provide insights to aid in the development of therapies for prevention of preterm birth. STATEMENT OF SIGNIFICANCE Preterm Birth (PTB) still represents a serious challenge to be overcome, considering its implications on infant mortality and lifelong health consequences. While the causes and etiologies of PTB are diverse and yet to be fully elucidated, a common pathway leading to a preterm delivery is premature cervical remodeling. Throughout pregnancy, the cervix remodels through changes of its microstructure, thus altering its mechanical properties. An appropriate timing for these transformations is critical for a healthy pregnancy and avoidance of PTB. Hence, this study aims at understanding how the mechanical function of the cervix evolves during a normal and preterm pregnancy. By performing cyclic mechanical testing on cervix samples from animal models, we assess the cervix's ability to recover from moderate and severe loading. The developed methodology links mechanical parameters to specific microstructural components. This work identifies a distinct biomechanical signature associated with inflammation mediated PTB that differs from PTB induced by hormone withdrawal and from normal term remodeling.
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Affiliation(s)
- C Jayyosi
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - N Lee
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - A Willcockson
- Department of Obstetrics and Gynecology and Green Center for Reproductive Biological Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - S Nallasamy
- Department of Obstetrics and Gynecology and Green Center for Reproductive Biological Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - M Mahendroo
- Department of Obstetrics and Gynecology and Green Center for Reproductive Biological Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - K Myers
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA.
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Ferruzzi J, Di Achille P, Tellides G, Humphrey JD. Combining in vivo and in vitro biomechanical data reveals key roles of perivascular tethering in central artery function. PLoS One 2018; 13:e0201379. [PMID: 30192758 PMCID: PMC6128471 DOI: 10.1371/journal.pone.0201379] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 07/14/2018] [Indexed: 12/30/2022] Open
Abstract
Considerable insight into effectors of cardiovascular function can be gleaned from controlled studies on mice, especially given the diverse models that are available. Toward this end, however, there is a need for consistent and complementary methods of in vivo and in vitro data analysis, synthesis, and interpretation. The overall objective of this study is twofold. First, we present new semi-automated methods to quantify in vivo measurements of vascular function in anesthetized mice as well as new approaches to synthesize these data with those from in vitro biaxial mechanical characterizations. Second, we contrast regional differences in biomechanical behaviors along the central vasculature by combining biaxial strains measured in vivo with data on the unloaded geometry and biaxial material properties measured in vitro. Results support the hypothesis that the healthy ascending aorta stores significant elastic energy during systole, which is available to work on the heart and blood during diastole, particularly during periods of physical exertion, and further suggest that perivascular tethering allows arteries to work at lower values of wall stress and material stiffness than often assumed. The numerous measurements of vascular function and properties provided herein can also serve as reference values for normal wild-type male and female mice, to which values for myriad genetic, surgical, and pharmacological models can be compared in future studies.
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Affiliation(s)
- Jacopo Ferruzzi
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States of America
| | - Paolo Di Achille
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States of America
| | - George Tellides
- Department of Surgery, Yale School of Medicine, New Haven, CT, United States of America
- Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, United States of America
| | - Jay D. Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States of America
- Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, United States of America
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Ogola BO, Zimmerman MA, Clark GL, Abshire CM, Gentry KM, Miller KS, Lindsey SH. New insights into arterial stiffening: does sex matter? Am J Physiol Heart Circ Physiol 2018; 315:H1073-H1087. [PMID: 30028199 DOI: 10.1152/ajpheart.00132.2018] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This review discusses sexual dimorphism in arterial stiffening, disease pathology interactions, and the influence of sex on mechanisms and pathways. Arterial stiffness predicts cardiovascular mortality independent of blood pressure. Patients with increased arterial stiffness have a 48% higher risk for developing cardiovascular disease. Like other cardiovascular pathologies, arterial stiffness is sexually dimorphic. Young women have lower stiffness than aged-matched men, but this sex difference reverses during normal aging. Estrogen therapy does not attenuate progressive stiffening in postmenopausal women, indicating that currently prescribed drugs do not confer protection. Although remodeling of large arteries is a protective adaptation to higher wall stress, arterial stiffening increases afterload to the left ventricle and transmits higher pulsatile pressure to smaller arteries and target organs. Moreover, an increase in aortic stiffness may precede or exacerbate hypertension, particularly during aging. Additional studies are needed to elucidate the mechanisms by which females are protected from arterial stiffness to provide insight into its mechanisms and, ultimately, therapeutic targets for treating this pathology.
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Affiliation(s)
- Benard O Ogola
- Department of Pharmacology, Tulane University , New Orleans, Louisiana
| | | | - Gabrielle L Clark
- Department of Biomedical Engineering, Tulane University , New Orleans, Louisiana
| | - Caleb M Abshire
- Department of Pharmacology, Tulane University , New Orleans, Louisiana
| | - Kaylee M Gentry
- Department of Pharmacology, Tulane University , New Orleans, Louisiana
| | - Kristin S Miller
- Department of Biomedical Engineering, Tulane University , New Orleans, Louisiana
| | - Sarah H Lindsey
- Department of Pharmacology, Tulane University , New Orleans, Louisiana
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50
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Bersi MR, Khosravi R, Wujciak AJ, Harrison DG, Humphrey JD. Differential cell-matrix mechanoadaptations and inflammation drive regional propensities to aortic fibrosis, aneurysm or dissection in hypertension. J R Soc Interface 2018; 14:rsif.2017.0327. [PMID: 29118111 DOI: 10.1098/rsif.2017.0327] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 10/17/2017] [Indexed: 01/01/2023] Open
Abstract
The embryonic lineage of intramural cells, microstructural organization of the extracellular matrix, local luminal and wall geometry, and haemodynamic loads vary along the length of the aorta. Yet, it remains unclear why certain diseases manifest differentially along the aorta. Toward this end, myriad animal models provide insight into diverse disease conditions-including fibrosis, aneurysm and dissection-but inherent differences across models impede general interpretations. We examined region-specific cellular, matrix, and biomechanical changes in a single experimental model of hypertension and atherosclerosis, which commonly coexist. Our findings suggest that (i) intramural cells within the ascending aorta are unable to maintain the intrinsic material stiffness of the wall, which ultimately drives aneurysmal dilatation, (ii) a mechanical stress-initiated, inflammation-driven remodelling within the descending aorta results in excessive fibrosis, and (iii) a transient loss of adventitial collagen within the suprarenal aorta contributes to dissection propensity. Smooth muscle contractility helps to control wall stress in the infrarenal aorta, which maintains mechanical properties near homeostatic levels despite elevated blood pressure. This early mechanoadaptation of the infrarenal aorta does not preclude subsequent acceleration of neointimal formation, however. Because region-specific conditions may be interdependent, as, for example, diffuse central arterial stiffening can increase cyclic haemodynamic loads on an aneurysm that is developing proximally, there is a clear need for more systematic assessments of aortic disease progression, not simply a singular focus on a particular region or condition.
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Affiliation(s)
- M R Bersi
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - R Khosravi
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - A J Wujciak
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - D G Harrison
- Department of Medicine, Vanderbilt University, Nashville, TN, USA.,Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - J D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA .,Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA
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