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Dill MN, Tabatabaei M, Kamat M, Basso KB, Moore E, Simmons CS. Generation and characterization of two immortalized dermal fibroblast cell lines from the spiny mouse (Acomys). PLoS One 2023; 18:e0280169. [PMID: 37418364 PMCID: PMC10328323 DOI: 10.1371/journal.pone.0280169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 06/14/2023] [Indexed: 07/09/2023] Open
Abstract
The spiny mouse (Acomys) is gaining popularity as a research organism due to its phenomenal regenerative capabilities. Acomys recovers from injuries to several organs without fibrosis. For example, Acomys heals full thickness skin injuries with rapid re-epithelialization of the wound and regeneration of hair follicles, sebaceous glands, erector pili muscles, adipocytes, and dermis without scarring. Understanding mechanisms of Acomys regeneration may uncover potential therapeutics for wound healing in humans. However, access to Acomys colonies is limited and primary fibroblasts can only be maintained in culture for a limited time. To address these obstacles, we generated immortalized Acomys dermal fibroblast cell lines using two methods: transfection with the SV40 large T antigen and spontaneous immortalization. The two cell lines (AcoSV40 and AcoSI-1) maintained the morphological and functional characteristics of primary Acomys fibroblasts, including maintenance of key fibroblast markers and ECM deposition. The availability of these cells will lower the barrier to working with Acomys as a model research organism, increasing the pace at which new discoveries to promote regeneration in humans can be made.
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Affiliation(s)
- Michele N. Dill
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, United States of America
| | - Mohammad Tabatabaei
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida, United States of America
| | - Manasi Kamat
- Department of Chemistry, University of Florida, Gainesville, Florida, United States of America
| | - Kari B. Basso
- Department of Chemistry, University of Florida, Gainesville, Florida, United States of America
| | - Erika Moore
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida, United States of America
| | - Chelsey S. Simmons
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, United States of America
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida, United States of America
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Zhou H, Llanes JP, Lotfi M, Sarntinoranont M, Simmons CS, Subhash G. Label-Free Quantification of Microscopic Alignment in Engineered Tissue Scaffolds by Polarized Raman Spectroscopy. ACS Biomater Sci Eng 2023; 9:3206-3218. [PMID: 37170804 DOI: 10.1021/acsbiomaterials.3c00242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Monitoring of extracellular matrix (ECM) microstructure is essential in studying structure-associated cellular processes, improving cellular function, and for ensuring sufficient mechanical integrity in engineered tissues. This paper describes a novel method to study the microscale alignment of the matrix in engineered tissue scaffolds (ETS) that are usually composed of a variety of biomacromolecules derived by cells. First, a trained loading function was derived from Raman spectra of highly aligned native tissue via principal component analysis (PCA), where prominent changes associated with specific Raman bands (e.g., 1444, 1465, 1605, 1627-1660, and 1665-1689 cm-1) were detected with respect to the polarization angle. These changes were mainly caused by the aligned matrix of many compounds within the tissue relative to the laser polarization, including proteins, lipids, and carbohydrates. Hence this trained function was applied to quantify the alignment within ETS of various matrix components derived by cells. Furthermore, a simple metric called Amplitude Alignment Metric (AAM) was derived to correlate the orientation dependence of polarized Raman spectra of ETS to the degree of matrix alignment. It was found that the AAM was significantly higher in anisotropic ETS than isotropic ones. The PRS method revealed a lower p-value for distinguishing the alignment between these two types of ETS as compared to the microscopic method for detecting fluorescent-labeled protein matrices at a similar microscopic scale. These results indicate that the anisotropy of a complex matrix in engineered tissue can be assessed at the microscopic scale using a PRS-based simple metric, which is superior to the traditional microscopic method. This PRS-based method can serve as a complementary tool for the design and assessment of engineered tissues that mimic the native matrix organizational microstructures.
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Affiliation(s)
- Hui Zhou
- Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Janny Piñeiro Llanes
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Maedeh Lotfi
- Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Malisa Sarntinoranont
- Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Chelsey S Simmons
- Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Ghatu Subhash
- Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611, United States
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Gaire J, Supper V, Montgomery D, Simmons CS. Spiny mice (Acomys) cells fail to engraft in NOD scid gamma. PLoS One 2023; 18:e0286000. [PMID: 37205673 DOI: 10.1371/journal.pone.0286000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 05/06/2023] [Indexed: 05/21/2023] Open
Abstract
Immune cells and stromal cells regulate wound healing and regeneration through complex activation patterns with spatiotemporal variation. The scarless regeneration of Spiny mice (Acomys species) is no exception; differential activation of immune and stromal cell populations seems to play a role in its remarkable regenerative capacity. To elucidate the role and interplay of Acomys immune cells in mammalian regeneration, we sought to create Acomys-Mus chimeras by transplanting bone marrow (BM) from Acomys into NOD Scid Gamma (NSG), a severely immunodeficient mouse line often used in creating humanized mice. Here, we report that Acomys BM cells fail to reconstitute and differentiate when transferred to irradiated NSG adults and neonates. In addition, we did not detect the presence of donor cells nor observe the onset of Graft versus Host Disease (GvHD)-like pathology, even after transplanting Acomys splenocytes in Acomys-Mus chimeras suggesting early graft failure. Overall, these results demonstrate the adoptive transfer of Acomys BM alone is not sufficient to establish Acomys hematopoietic system in NSG mouse.
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Affiliation(s)
- Janak Gaire
- Department of Mechanical & Aerospace Engineering, University of Florida, Gainesville, Florida, United States of America
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, United States of America
| | - Valentina Supper
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, United States of America
| | - Darrice Montgomery
- Department of Mechanical & Aerospace Engineering, University of Florida, Gainesville, Florida, United States of America
| | - Chelsey S Simmons
- Department of Mechanical & Aerospace Engineering, University of Florida, Gainesville, Florida, United States of America
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, United States of America
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Rana S, Sunshine MD, Gaire J, Simmons CS, Fuller DD. Breathing patterns and CO 2 production in adult spiny mice (Acomys cahirinus). Respir Physiol Neurobiol 2023; 307:103975. [PMID: 36206972 PMCID: PMC10112007 DOI: 10.1016/j.resp.2022.103975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 09/09/2022] [Accepted: 10/02/2022] [Indexed: 11/06/2022]
Abstract
The spiny mouse (Acomys) is a precocial mammal with unique regenerative abilities. We used whole-body plethysmography to describe the breathing patterns and CO2 production (VCO2) of adult spiny mice (n = 10 male, 10 female) and C57BL/6 mice (n = 9 male, 11 female). During quiet breathing, female but not male spiny mice had lower tidal volumes and CO2 production vs. C57BL/6 mice. During extended hypoxia (30 min), male and female spiny mice decreased VCO2 and tidal volume to a greater degree than C57BL/6 mice. During an acute hypoxic-hypercapnic respiratory challenge (10% O2, 7% CO2), male and female spiny mice had blunted ventilatory responses as compared to C57BL/6 mice, primarily from a diminished increase in respiratory rate. These data establish a baseline for studies of respiratory physiology and neurobiology in spiny mice in the context of their remarkable regenerative capacity and their unique background of a desert dwelling species.
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Affiliation(s)
- Sabhya Rana
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA; Breathing Research and Therapeutics Center, Gainesville, FL 32610, USA
| | - Michael D Sunshine
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA; Breathing Research and Therapeutics Center, Gainesville, FL 32610, USA
| | - Janak Gaire
- Department of Mechanical & Aerospace Engineering, University of Florida, USA
| | - Chelsey S Simmons
- Department of Mechanical & Aerospace Engineering, University of Florida, USA; J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, USA
| | - David D Fuller
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA; Breathing Research and Therapeutics Center, Gainesville, FL 32610, USA.
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Simmons CS, Roche C, Schoch BS, Parsons M, Aibinder WR. Surgeon confidence in planning total shoulder arthroplasty improves after consulting a clinical decision support tool. Eur J Orthop Surg Traumatol 2022:10.1007/s00590-022-03446-1. [PMID: 36436090 DOI: 10.1007/s00590-022-03446-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Accepted: 11/20/2022] [Indexed: 06/16/2023]
Abstract
PURPOSE Software algorithms are increasingly available as clinical decision support tools (CDSTs) to support shared decision-making. We sought to understand if patient-specific predictions from a CDST would impact orthopedic surgeons' preoperative planning decisions and corresponding confidence. METHODS We performed a survey study of orthopedic surgeons with at minimum of 2 years of independent shoulder arthroplasty experience. We generated patient profiles for 18 faux cases presenting with glenohumeral osteoarthritis and emailed 93 surgeons requesting their recommendation for anatomic or reverse total shoulder arthroplasty for each case and their certainty in their recommendation on a 4-point Likert scale. The thirty respondents were later sent a second survey with the same cases that now included predicted patient-specific outcomes and complication rates generated by a CDST. RESULTS Initial recommendations and changes in recommendation varied widely by surgeon and by case. After viewing the results of the CDST, surgeons switched from anatomic to reverse recommendations in 46 instances (12% of initial anatomic) and from reverse to anatomic in 22 instances (6% of initial reverse). Overall, surgeon change in confidence increased significantly across all responses (p = 0.0001), with certain cases and certain surgeons having significant changes. Change in confidence did not correlate with surgeon-specific factors, including years in practice. CONCLUSION The addition of CDST reports to preoperative planning for anatomic and reverse total shoulder arthroplasty informed decision-making but did not direct recommendations uniformly. However, the CDST information provided did increase surgeon confidence regardless of implant selection and irrespective of surgeon experience.
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Affiliation(s)
| | | | - Bradley S Schoch
- Department of Orthopedic Surgery, Mayo Clinic, Jacksonville, FL, USA
| | - Moby Parsons
- The Knee Hip and Shoulder Center, Portsmouth, NH, USA
| | - William R Aibinder
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA.
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Piñeiro-Llanes J, Suzuki-Hatano S, Jain A, Pérez Medina VA, Cade WT, Pacak CA, Simmons CS. Matrix produced by diseased cardiac fibroblasts affects early myotube formation and function. Acta Biomater 2022; 152:100-112. [PMID: 36055608 PMCID: PMC10625442 DOI: 10.1016/j.actbio.2022.08.060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 08/25/2022] [Accepted: 08/25/2022] [Indexed: 11/28/2022]
Abstract
The extracellular matrix (ECM) provides both physical and chemical cues that dictate cell function and contribute to muscle maintenance. Muscle cells require efficient mitochondria to satisfy their high energy demand, however, the role the ECM plays in moderating mitochondrial function is not clear. We hypothesized that the ECM produced by stromal cells with mitochondrial dysfunction (Barth syndrome, BTHS) provides cues that contribute to metabolic dysfunction independent of muscle cell health. To test this, we harnessed the ECM production capabilities of human pluripotent stem-cell-derived cardiac fibroblasts (hPSC-CFs) from healthy and BTHS patients to fabricate cell-derived matrices (CDMs) with controlled topography, though we found that matrix composition from healthy versus diseased cells influenced myotube formation independent of alignment cues. To further investigate the effects of matrix composition, we then examined the influence of healthy- and BTHS-derived CDMs on myotube formation and metabolic function. We found that BTHS CDMs induced lower fusion index, lower ATP production, lower mitochondrial membrane potential, and higher ROS generation than the healthy CDMs. These findings imply that BTHS-derived ECM alone contributes to myocyte dysfunction in otherwise healthy cells. Finally, to investigate potential mechanisms, we defined the composition of CDMs produced by hPSC-CFs from healthy and BTHS patients using mass spectrometry and identified 15 ECM and related proteins that were differentially expressed in the BTHS-CDM compared to healthy CDM. Our results highlight that ECM composition affects skeletal muscle formation and metabolic efficiency in otherwise healthy cells, and our methods to generate patient-specific CDMs are a useful tool to investigate the influence of the ECM on disease progression and to investigate variability among diseased patients. STATEMENT OF SIGNIFICANCE: Muscle function requires both efficient metabolism to generate force and structured extracellular matrix (ECM) to transmit force, and we sought to examine the interactions between metabolism and ECM when metabolic disease is present. We fabricated patient-specific cell derived matrices (CDMs) with controlled topographic features to replicate the composition of healthy and mitochondrial-diseased (Barth syndrome) ECM. We found that disease-derived ECM negatively affects metabolic function of otherwise healthy myoblasts, and we identified several proteins in disease-derived ECM that may be mediating this dysfunction. We anticipate that our patient-specific CDM system could be fabricated with other topographies and cell types to study cell functions and diseases of interest beyond mitochondrial dysfunction and, eventually, be applied toward personalized medicine.
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Affiliation(s)
- Janny Piñeiro-Llanes
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Silveli Suzuki-Hatano
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Ananya Jain
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Valerie A Pérez Medina
- Department of Mechanical Engineering, University of Puerto Rico, Mayaguez 00682, Puerto Rico
| | - William Todd Cade
- Physical Therapy Division, Duke University, 311 Trent Drive, Durham, NC 27710, USA
| | - Christina A Pacak
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL 32610, USA; Neurology Department, Medical School, University of Minnesota, WMBB 4-188 2101 6th Street SE, Minneapolis 55455, USA
| | - Chelsey S Simmons
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL 32611, USA; Department of Mechanical and Aerospace Engineering Herbert Wertheim College of Engineering, University of Florida.
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Sapru S, Dill MN, Simmons CS. Biomaterial Design Inspired by Regenerative Research Organisms. ACS Biomater Sci Eng 2022. [PMID: 36222692 DOI: 10.1021/acsbiomaterials.2c00486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The efficacy of implanted biomaterials is largely dependent on the response of the host's immune and stromal cells. Severe foreign body response (FBR) can impede the integration of the implant into the host tissue and compromise the intended mechanical and biochemical function. Many features of FBR, including late-stage fibrotic encapsulation of implants, parallel the formation of fibrotic scar tissue after tissue injury. Regenerative organisms like zebrafish and salamanders can avoid fibrosis after injury entirely, but FBR in these research organisms is rarely investigated because their immune competence is much lower than humans. The recent characterization of a regenerative mammal, the spiny mouse (Acomys), has inspired us to take a closer look at cellular regulation in regenerative organisms across the animal kingdom for insights into avoiding FBR in humans. Here, we highlight how major features of regeneration, such as blastema formation, macrophage polarization, and matrix composition, can be modulated across a range of regenerative research organisms to elucidate common features that may be harnessed to minimize FBR. Leveraging a deeper understanding of regenerative biology for biomaterial design may help to reduce FBR and improve device integration and performance.
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Affiliation(s)
- Sunaina Sapru
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Michele N Dill
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Chelsey S Simmons
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611, United States.,J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611, United States
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Piñeiro-Llanes J, Rodriguez CD, Farhadi SA, Hudalla GA, Sarntinoranont M, Simmons CS. Experimental and Computational Models of Transport of Galectin-3 Through Glycosylated Matrix. Ann Biomed Eng 2022; 50:703-715. [PMID: 35352215 PMCID: PMC10621651 DOI: 10.1007/s10439-022-02949-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 03/09/2022] [Indexed: 11/01/2022]
Abstract
Altered extracellular matrix (ECM) production is a hallmark of many fibroproliferative diseases, including certain cancers. The high incidence of glycan-rich components within altered ECM makes the use of glycan-binding proteins such as Galectin-3 (G3) a promising therapeutic strategy. The complexity of ECM as a rich 3D network of proteins with varied glycosylation states makes it challenging to determine the retention of glycan-binding proteins in altered ECM environments. Computational models capable of predicting the transport of glycan-binding proteins in altered ECM can benefit the design and testing of such proteins and associated novel therapeutic strategies. However, such computational models require many kinetic parameters that cannot be estimated from traditional 2D pharmacokinetic assays. To validate transport properties of G3 in 3D ECM constructs, we developed a species transport model that includes diffusion and matrix-binding components to predict retention of G3 fusion proteins in glycan-rich ECM. By iteratively comparing our computational model to experimental results, we are able to determine a reasonable range of parameters for a robust computational model of G3 transport. We anticipate this overall approach to building a data-driven model is translatable to other ECM-targeting therapeutic strategies.
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Affiliation(s)
- Janny Piñeiro-Llanes
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Camille D Rodriguez
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Shaheen A Farhadi
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Gregory A Hudalla
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Malisa Sarntinoranont
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, 32611, USA
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Chelsey S Simmons
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, 32611, USA.
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, 32611, USA.
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Zhou H, Piñeiro Llanes J, Sarntinoranont M, Subhash G, Simmons CS. Label-free quantification of soft tissue alignment by polarized Raman spectroscopy. Acta Biomater 2021; 136:363-374. [PMID: 34537413 DOI: 10.1016/j.actbio.2021.09.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 08/24/2021] [Accepted: 09/09/2021] [Indexed: 11/29/2022]
Abstract
The organization of proteins is an important determinant of functionality in soft tissues. However, such organization is difficult to monitor over time in soft tissue with complex compositions. Here, we establish a method to determine the alignment of proteins in soft tissues of varying composition by polarized Raman spectroscopy (PRS). Unlike most conventional microscopy methods, PRS leverages non-destructive, label-free sample preparation. PRS data from highly aligned muscle layers were utilized to derive a weighting function for aligned proteins via principal component analysis (PCA). This trained weighting function was used as a master loading function to calculate a principal component score (PC1 Score) as a function of polarized angle for tendon, dermis, hypodermis, and fabricated collagen gels. Since the PC1 Score calculated at arbitrary angles was insufficient to determine level of alignment, we developed an Amplitude Alignment Metric by fitting a sine function to PC1 Score with respect to polarized angle. We found that our PRS-based Amplitude Alignment Metric can be used as an indicator of level of protein alignment in soft tissues in a non-destructive manner with label-free preparation and has similar discriminatory capacity among isotropic and anisotropic samples compared to microscopy-based image processing method. This PRS method does not require a priori knowledge of sample orientation nor composition and appears insensitive to changes in protein composition among different tissues. The Amplitude Alignment Metric introduced here could enable convenient and adaptable evaluation of protein alignment in soft tissues of varying protein and cell composition. STATEMENT OF SIGNIFICANCE: Polarized Raman spectroscopy (PRS) has been used to characterize the of organization of soft tissues. However, most of the reported applications of PRS have been on collagen-rich tissues and reliant on intensities of collagen-related vibrations. This work describes a PRS method via a multivariate analysis to characterize alignment in soft tissues composed of varying proteins. Of note, the highly aligned muscle layer of mouse skin was used to train a master function then applied to other soft tissue samples, and the degree of anisotropy in the PRS response was evaluated to obtain the level of alignment in tissues. We have demonstrated that this method supports convenient and adaptable evaluation of protein alignment in soft tissues of varying protein and cell composition.
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Affiliation(s)
- Hui Zhou
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, Florida, USA
| | - Janny Piñeiro Llanes
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, Florida, USA
| | - Malisa Sarntinoranont
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, Florida, USA
| | - Ghatu Subhash
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, Florida, USA
| | - Chelsey S Simmons
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, Florida, USA.
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Gaire J, Varholick JA, Rana S, Sunshine MD, Doré S, Barbazuk WB, Fuller DD, Maden M, Simmons CS. Spiny mouse (Acomys): an emerging research organism for regenerative medicine with applications beyond the skin. NPJ Regen Med 2021; 6:1. [PMID: 33397999 PMCID: PMC7782534 DOI: 10.1038/s41536-020-00111-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 11/13/2020] [Indexed: 12/01/2022] Open
Abstract
The spiny mouse (Acomys species) has emerged as an exciting research organism due to its remarkable ability to undergo scarless regeneration of skin wounds and ear punches. Excitingly, Acomys species demonstrate scar-free healing in a wide-range of tissues beyond the skin. In this perspective article, we discuss published findings from a variety of tissues to highlight how this emerging research organism could shed light on numerous clinically relevant human diseases. We also discuss the challenges of working with this emerging research organism and suggest strategies for future Acomys-inspired research.
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Affiliation(s)
- Janak Gaire
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, 32611, USA
| | - Justin A Varholick
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, 32611, USA
| | - Sabhya Rana
- Department of Physical Therapy, University of Florida, Gainesville, 32611, USA
| | - Michael D Sunshine
- Department of Physical Therapy, University of Florida, Gainesville, 32611, USA
| | - Sylvain Doré
- Department of Anesthesiology, University of Florida, Gainesville, 32611, USA
| | - W Brad Barbazuk
- Department of Biology and UF Genetics Institute, University of Florida, Gainesville, 32611, USA
| | - David D Fuller
- Department of Physical Therapy, University of Florida, Gainesville, 32611, USA.,McKnight Brain Institute and Center for Breathing Research and Therapeutics, University of Florida, Gainesville, 32611, USA
| | - Malcolm Maden
- Department of Biology and UF Genetics Institute, University of Florida, Gainesville, 32611, USA
| | - Chelsey S Simmons
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, 32611, USA. .,J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, 32611, USA.
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De La Pena A, Mukhtar M, Yokosawa R, Carrasquilla S, Simmons CS. Quantifying cellular forces: Practical considerations of traction force microscopy for dermal fibroblasts. Exp Dermatol 2021; 30:74-83. [PMID: 32767472 PMCID: PMC7769991 DOI: 10.1111/exd.14166] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/12/2020] [Accepted: 07/30/2020] [Indexed: 12/28/2022]
Abstract
Traction force microscopy (TFM) is a well-established technique traditionally used by biophysicists to quantify the forces adherent biological cells exert on their microenvironment. As image processing software becomes increasingly user-friendly, TFM is being adopted by broader audiences to quantify contractility of (myo)fibroblasts. While many technical reviews of TFM's computational mechanics are available, this review focuses on practical experimental considerations for dermatology researchers new to cell mechanics and TFM who may wish to implement a higher throughput and less expensive alternative to collagen compaction assays. Here, we describe implementation of experimental methods, analysis using open-source software and troubleshooting of common issues to enable researchers to leverage TFM for their investigations into skin fibroblasts.
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Affiliation(s)
| | | | | | | | - Chelsey S. Simmons
- Department of Mechanical and Aerospace Engineering
- J. Crayton Pruitt Department of Biomedical Engineering
- Division of Cardiovascular Medicine, University of Florida
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Zhou H, Simmons CS, Sarntinoranont M, Subhash G. Raman Spectroscopy Methods to Characterize the Mechanical Response of Soft Biomaterials. Biomacromolecules 2020; 21:3485-3497. [PMID: 32833438 DOI: 10.1021/acs.biomac.0c00818] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Raman spectroscopy has been used extensively to characterize the influence of mechanical deformation on microstructure changes in biomaterials. While traditional piezo-spectroscopy has been successful in assessing internal stresses of hard biomaterials by tracking prominent peak shifts, peak shifts due to applied loads are near or below the resolution limit of the spectrometer for soft biomaterials with moduli in the kilo- to mega-Pascal range. In this Review, in addition to peak shifts, other spectral features (e.g., polarized intensity and intensity ratio) that provide quantitative assessments of microstructural orientation and secondary structure in soft biomaterials and their strain dependence are discussed. We provide specific examples for each method and classify sensitive Raman characteristic bands common across natural (e.g., soft tissue) and synthetic (e.g., polymeric scaffolds) soft biomaterials upon mechanical deformation. This Review can provide guidance for researchers aiming to analyze micromechanics of soft tissues and engineered tissue constructs by Raman spectroscopy.
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Affiliation(s)
- Hui Zhou
- Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Chelsey S Simmons
- Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Malisa Sarntinoranont
- Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Ghatu Subhash
- Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611, United States
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Simmons CS, McCarty OJT, Tripathi A. A Theme Series on Emerging Technologies for Use in the Study, Diagnosis and Treatment of Patients with COVID-19. Cell Mol Bioeng 2020; 13:247-248. [PMID: 32837588 PMCID: PMC7418882 DOI: 10.1007/s12195-020-00645-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Chelsey S Simmons
- Department of Mechanical and Aerospace Engineering, J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL USA
| | - Owen J T McCarty
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR USA
| | - Anubhav Tripathi
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI USA
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Ryan H, Simmons CS. Potential Applications of Microfluidics to Acute Kidney Injury Associated with Viral Infection. Cell Mol Bioeng 2020; 13:305-311. [PMID: 32904757 PMCID: PMC7457440 DOI: 10.1007/s12195-020-00649-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 08/19/2020] [Indexed: 12/24/2022] Open
Abstract
The kidneys are susceptible to adverse effects from many diseases, including several that are not tissue-specific. Acute kidney injury is a common complication of systemic diseases such as diabetes, lupus, and certain infections including the novel coronavirus (SARS-CoV-2). Microfluidic devices are an attractive option for disease modeling, offering the opportunity to utilize human cells, control experimental and environmental conditions, and combine with other on-chip devices. For researchers with expertise in microfluidics, this brief perspective highlights potential applications of such devices to studying SARS-CoV-2-induced kidney injury.
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Affiliation(s)
- Holly Ryan
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, PO Box 116250, Gainesville, FL 32611 USA
- Department of Medicine, College of Medicine, University of Florida, Gainesville, USA
| | - Chelsey S. Simmons
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, PO Box 116250, Gainesville, FL 32611 USA
- Department of Medicine, College of Medicine, University of Florida, Gainesville, USA
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, USA
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Abstract
New technologies are being developed toward the novel coronavirus SARS-CoV-2 to understand its pathogenesis and transmission, to develop therapeutics and vaccines, and to formulate preventive strategies. Animal models are indispensable to understand these processes and develop and test emerging technologies; however, the mechanism of infection for SARS-CoV-2 requires certain similarities to humans that do not exist in common laboratory rodents. Here, we review important elements of viral infection, transmission, and clinical presentation reflected by various animal models readily available or being developed and studied for SARS-CoV-2 to help bioengineers evaluate appropriate preclinical models for their emerging technologies. Importantly, applications of traditional mice and rat models are limited for studying SARS-CoV-2 and development of COVID-19. Non-human primates, Syrian hamsters, ferrets, cats, and engineered chimeras mimic the human infection more closely and hold strong potential as animal models of SARS-CoV-2 infection and progression of resulting human disease.
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Affiliation(s)
- Jhinuk Basu Mullick
- Department of Mechanical & Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, PO Box 116250, Gainesville, FL 32611 USA
| | - Chelsey S. Simmons
- Department of Mechanical & Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, PO Box 116250, Gainesville, FL 32611 USA
- Division of Cardiovascular Medicine, J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, USA
| | - Janak Gaire
- Department of Mechanical & Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, PO Box 116250, Gainesville, FL 32611 USA
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Spearman BS, Agrawal NK, Rubiano A, Simmons CS, Mobini S, Schmidt CE. Tunable methacrylated hyaluronic acid-based hydrogels as scaffolds for soft tissue engineering applications. J Biomed Mater Res A 2020; 108:279-291. [PMID: 31606936 PMCID: PMC8591545 DOI: 10.1002/jbm.a.36814] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 09/26/2019] [Accepted: 10/01/2019] [Indexed: 01/18/2023]
Abstract
Hyaluronic acid (HA)-based biomaterials have been explored for a number of applications in biomedical engineering, particularly as tissue regeneration scaffolds. Crosslinked forms of HA are more robust and provide tunable mechanical properties and degradation rates that are critical in regenerative medicine; however, crosslinking modalities reported in the literature vary and there are few comparisons of different scaffold properties for various crosslinking approaches. In this study, we offer direct comparison of two methacrylation techniques for HA (glycidyl methacrylate HA [GMHA] or methacrylic anhydride HA [MAHA]). The two methods for methacrylating HA provide degrees of methacrylation ranging from 2.4 to 86%, reflecting a wider range of properties than is possible using only a single methacrylation technique. We have also characterized mechanical properties for nine different tissues isolated from rat (ranging from lung at the softest to muscle at the stiffest) using indentation techniques and show that we can match the full range of mechanical properties (0.35-6.13 kPa) using either GMHA or MAHA. To illustrate utility for neural tissue engineering applications, functional hydrogels with adhesive proteins (either GMHA or MAHA base hydrogels with collagen I and laminin) were designed with effective moduli mechanically matched to rat sciatic nerve (2.47 ± 0.31 kPa). We demonstrated ability of these hydrogels to support three-dimensional axonal elongation from dorsal root ganglia cultures. Overall, we have shown that methacrylated HA provides a tunable platform with a wide range of properties for use in soft tissue engineering.
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Affiliation(s)
- Benjamin S. Spearman
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL
| | - Nikunj K. Agrawal
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL
| | - Andrés Rubiano
- Department of Mechanical & Aerospace Engineering, University of Florida, Gainesville, FL
| | - Chelsey S. Simmons
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL
- Department of Mechanical & Aerospace Engineering, University of Florida, Gainesville, FL
| | - Sahba Mobini
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL
- Instituto de Micro y Nanotecnología, IMN-CNM, CSIC (CEI UAM+CSIC), Madrid, Spain
- Departamento de Biología Molecular and Centro de Biología Molecular, Universidad Autónoma de Madrid, Madrid, Spain
| | - Christine E. Schmidt
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL
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Rubiano A, Galitz C, Simmons CS. Mechanical Characterization by Mesoscale Indentation: Advantages and Pitfalls for Tissue and Scaffolds. Tissue Eng Part C Methods 2019; 25:619-629. [PMID: 30848168 DOI: 10.1089/ten.tec.2018.0372] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Regenerative medicine and tissue engineering are hindered by the lack of consistent measurements and standards for the mechanical characterization of tissue and scaffolds. Indentation methods for soft matter are favored because of their compatibility with small, arbitrarily shaped samples, but contact mechanics models required to interpret data are often inappropriate for soft, viscous materials. In this study, we demonstrate indentation experiments on a variety of human biopsies, animal tissue, and engineered scaffolds, and we explore the complexities of fitting analytical models to these data. Although objections exist to using Hertz contact models for soft, viscoelastic biological materials since soft matter violates their original assumptions, we demonstrate the experimental conditions that enable consistency and comparability (regardless of arguable misappropriation). Appropriate experimental conditions involving sample hydration, the indentation depth, and the ratio of the probe size to sample thickness enable repeatable metrics that are valuable when comparing synthetic scaffolds and host tissue, and bounds on these parameters are carefully described and discussed. We have also identified a reliable quasistatic parameter that can be derived from indentation data to help researchers compare results across materials and experiments. Although Hertz contact mechanics and linear viscoelastic models may constitute oversimplification for biological materials, the reporting of such simple metrics alongside more complex models is expected to support researchers in tissue engineering and regenerative medicine by providing consistency across efforts to characterize soft matter. Impact Statement To engineer replacement tissue requires a deep understanding of its biomechanical properties. Mesoscale indentation (between micron and millimeter length scales) is well-suited to characterize tissue and engineered replacements as it accommodates small, oddly shaped samples. However, it is easy to run afoul of the assumptions for common contact models when working with biological materials. In this study, we describe experimental procedures and modeling approaches that allow researchers to take advantage of indentation for biomechanical characterization while minimizing its weaknesses.
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Affiliation(s)
- Andrés Rubiano
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, Gainesville, Florida
| | - Carly Galitz
- Department of Mathematics, College of Liberal Arts and Sciences, Gainesville, Florida
| | - Chelsey S Simmons
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, Gainesville, Florida.,J. Crayton Pruitt Family Department of Biomedical Engineering Herbert Wertheim College of Engineering, Gainesville, Florida.,Division of Cardiovascular Medicine, College of Medicine, University of Florida, Gainesville, Florida
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Nakayama KH, Quarta M, Paine P, Alcazar C, Karakikes I, Garcia V, Abilez OJ, Calvo NS, Simmons CS, Rando TA, Huang NF. Treatment of volumetric muscle loss in mice using nanofibrillar scaffolds enhances vascular organization and integration. Commun Biol 2019; 2:170. [PMID: 31098403 PMCID: PMC6505043 DOI: 10.1038/s42003-019-0416-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 04/05/2019] [Indexed: 12/15/2022] Open
Abstract
Traumatic skeletal muscle injuries cause irreversible tissue damage and impaired revascularization. Engineered muscle is promising for enhancing tissue revascularization and regeneration in injured muscle. Here we fabricated engineered skeletal muscle composed of myotubes interspersed with vascular endothelial cells using spatially patterned scaffolds that induce aligned cellular organization, and then assessed their therapeutic benefit for treatment of murine volumetric muscle loss. Murine skeletal myoblasts co-cultured with endothelial cells in aligned nanofibrillar scaffolds form endothelialized and aligned muscle with longer myotubes, more synchronized contractility, and more abundant secretion of angiogenic cytokines, compared to endothelialized engineered muscle formed from randomly-oriented scaffolds. Treatment of traumatically injured muscle with endothelialized and aligned skeletal muscle promotes the formation of highly organized myofibers and microvasculature, along with greater vascular perfusion, compared to treatment of muscle derived from randomly-oriented scaffolds. This work demonstrates the potential of endothelialized and aligned engineered skeletal muscle to promote vascular regeneration following transplantation.
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Affiliation(s)
- Karina H. Nakayama
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 USA
- The Stanford Cardiovascular Institute, Stanford University, Stanford, CA 94305 USA
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA 94305 USA
| | - Marco Quarta
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 USA
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94304 USA
| | - Patrick Paine
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 USA
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94304 USA
| | - Cynthia Alcazar
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 USA
| | - Ioannis Karakikes
- The Stanford Cardiovascular Institute, Stanford University, Stanford, CA 94305 USA
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA 94305 USA
| | - Victor Garcia
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 USA
| | - Oscar J. Abilez
- The Stanford Cardiovascular Institute, Stanford University, Stanford, CA 94305 USA
| | - Nicholas S. Calvo
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainsville, FL 32611 USA
| | - Chelsey S. Simmons
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainsville, FL 32611 USA
| | - Thomas A. Rando
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 USA
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94304 USA
| | - Ngan F. Huang
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 USA
- The Stanford Cardiovascular Institute, Stanford University, Stanford, CA 94305 USA
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA 94305 USA
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19
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Jiang K, Chaimov D, Patel SN, Liang JP, Wiggins SC, Samojlik MM, Rubiano A, Simmons CS, Stabler CL. 3-D physiomimetic extracellular matrix hydrogels provide a supportive microenvironment for rodent and human islet culture. Biomaterials 2019; 198:37-48. [PMID: 30224090 PMCID: PMC6397100 DOI: 10.1016/j.biomaterials.2018.08.057] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 07/31/2018] [Accepted: 08/27/2018] [Indexed: 01/19/2023]
Abstract
Organ-on-a-chip platforms serve as cost-efficient testbeds for screening pharmaceutical agents, mimicking natural physiology, and studying disease. In the field of diabetes, the development of an islet-on-a-chip platform would have broad implications in understanding disease pathology and discovering potential therapies. Islet microphysiological systems are limited, however, by their poor cell survival and function in culture. A key factor that has been implicated in this decline is the disruption of islet-matrix interactions following isolation. Herein, we sought to recapitulate the in vivo peri-islet niche using decellularized extracellular matrix (ECM) hydrogels. Sourcing from porcine bladder, lung, and pancreas tissues, 3-D ECM hydrogels were generated, characterized, and validated using both rodent and human pancreatic islets. Optimized decellularization protocols resulted in hydrogels with distinctive viscoelastic properties that correlated to their matrix composition. The in situ 3-D encapsulation of human or rat islets within ECM hydrogels resulted in improved functional stability over standard culture conditions. Islet composition and morphology were also altered, with enhanced retention of islet-resident endothelial cells and the formation of cord-like structures or sprouts emerging from the islet spheroid. These supportive 3-D physiomimetic ECM hydrogels can be leveraged within microfluidic platforms for the long-term culture of islets.
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Affiliation(s)
- K Jiang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, United States
| | - D Chaimov
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, United States
| | - S N Patel
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, United States
| | - J-P Liang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, United States
| | - S C Wiggins
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, United States
| | - M M Samojlik
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, United States
| | - A Rubiano
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, United States
| | - C S Simmons
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, United States; Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, United States
| | - C L Stabler
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, United States.
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20
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Stewart DC, Serrano PN, Rubiano A, Yokosawa R, Sandler J, Mukhtar M, Brant JO, Maden M, Simmons CS. Unique behavior of dermal cells from regenerative mammal, the African Spiny Mouse, in response to substrate stiffness. J Biomech 2018; 81:149-154. [PMID: 30361050 DOI: 10.1016/j.jbiomech.2018.10.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 10/08/2018] [Accepted: 10/09/2018] [Indexed: 01/30/2023]
Abstract
The African Spiny Mouse (Acomys spp.) is a unique outbred mammal capable of full, scar-free skin regeneration. In vivo, we have observed rapid reepithelialization and deposition of normal dermis in Acomys after wounding. Acomys skin also has a lower modulus and lower elastic energy storage than normal lab mice, Mus musculus. To see if the different in vivo mechanical microenvironments retained an effect on dermal cells and contributed to regenerative behavior, we examined isolated keratinocytes in response to physical wounding and fibroblasts in response to varying substrate stiffness. Classic mechanobiology paradigms suggest stiffer substrates will promote myofibroblast activation, but we do not see this in Acomys dermal fibroblasts (DFs). Though Mus DFs increase organization of α-smooth muscle actin (αSMA)-positive stress fibers as substrate stiffness increases, Acomys DFs assemble very few αSMA-positive stress fibers upon changes in substrate stiffness. Acomys DFs generate lower traction forces than Mus DFs on pliable surfaces, and Acomys DFs produce and modify matrix proteins differently than Mus in 2D and 3D culture systems. In contrast to Acomys DFs "relaxed" behavior, we found that freshly isolated Acomys keratinocytes retain the ability to close wounds faster than Mus in an in vitro scratch assay. Taken together, these preliminary observations suggest that Acomys dermal cells retain unique biophysical properties in vitro that may reflect their altered in vivo mechanical microenvironment and may promote scar-free wound healing.
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Affiliation(s)
- Daniel C Stewart
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, PO Box 116131, Gainesville, FL 32611-6131, USA
| | - P Nicole Serrano
- Department of Biology, College of Liberal Arts and Sciences, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA
| | - Andrés Rubiano
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, PO Box 116250, Gainesville, FL 32611-6250, USA
| | - Ryosuke Yokosawa
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, PO Box 116250, Gainesville, FL 32611-6250, USA
| | - Justin Sandler
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, PO Box 116250, Gainesville, FL 32611-6250, USA
| | - Marah Mukhtar
- Department of Materials Science and Engineering, Herbert Wertheim College of Engineering, University of Florida, PO Box 116250, Gainesville, FL 32611-6250, USA
| | - Jason O Brant
- Department of Biology, College of Liberal Arts and Sciences, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA
| | - Malcolm Maden
- Department of Biology, College of Liberal Arts and Sciences, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA
| | - Chelsey S Simmons
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, PO Box 116131, Gainesville, FL 32611-6131, USA; Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, PO Box 116250, Gainesville, FL 32611-6250, USA; Division of Cardiovascular Medicine, Department of Medicine, College of Medicine, University of Florida, 1600 SW Archer Road, Gainesville, FL 32610-0277, USA.
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21
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Stewart DC, Berrie D, Li J, Liu X, Rickerson C, Mkoji D, Iqbal A, Tan S, Doty AL, Glover SC, Simmons CS. Quantitative assessment of intestinal stiffness and associations with fibrosis in human inflammatory bowel disease. PLoS One 2018; 13:e0200377. [PMID: 29995938 PMCID: PMC6040714 DOI: 10.1371/journal.pone.0200377] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 06/25/2018] [Indexed: 01/05/2023] Open
Abstract
Inflammatory bowel disease (IBD) continues to increase in prevalence in industrialized countries. Major complications of IBD include formation of fibrotic strictures, fistulas, reduced absorptive function, cancer risk, and the need for surgery. In other chronic gastrointestinal disease models, stiffness has been shown to precede fibrosis; therefore, stiffness may be a reasonable indicator of progression toward stricture formation in IBD patients. Herein, we seek to quantify tissue stiffness and characterize fibrosis in patients with IBD and to compare mechanical properties of unaffected human tissue to common animal species used for IBD studies. Inflamed and unaffected tissue from IBD patients and unaffected tissue from mice, pigs, and cows were indented using a custom device to determine the effective stiffness. Histology was performed on matched tissues, and total RNA was isolated from IBD tissue samples and used for gene expression analysis of pro-fibrotic genes. We observed an increase in the effective stiffness (steady-state modulus, SSM) (p < 0.0001) and increased expression of the collagen type I gene (COL1A1, p = 0.01) in inflamed tissue compared to unaffected areas in our IBD patient cohort. We also found that increased staining of collagen fibers in submucosa positively correlated with SSM (p = 0.093). We determined that unaffected animal bowel stiffness is significantly greater than similar human tissues, suggesting additional limitations on animal models for translational investigations regarding stiffness-related hypotheses. Taken together, our data support development of tools for evaluation of bowel stiffness in IBD patients for prognostic applications that may enable more accurate prediction of those who will develop fibrosis and more precise prescription of aggressive therapies.
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Affiliation(s)
- Daniel C. Stewart
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, United States of America
| | - Dalton Berrie
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, United States of America
- Division of Gastroenterology, Hepatology and Nutrition, College of Medicine, University of Florida, Gainesville, FL, United States of America
| | - Jian Li
- Division of Gastroenterology, Hepatology and Nutrition, College of Medicine, University of Florida, Gainesville, FL, United States of America
| | - Xinyue Liu
- Department of Pharmaceutical Outcomes and Policy, College of Pharmacy, University of Florida, Gainesville, FL, United States of America
| | - Cooper Rickerson
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, United States of America
| | - David Mkoji
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, United States of America
| | - Atif Iqbal
- Department of Surgery, College of Medicine, University of Florida, Gainesville, FL, United States of America
| | - Sanda Tan
- Department of Surgery, College of Medicine, University of Florida, Gainesville, FL, United States of America
| | - Andria L. Doty
- Division of Gastroenterology, Hepatology and Nutrition, College of Medicine, University of Florida, Gainesville, FL, United States of America
| | - Sarah C. Glover
- Division of Gastroenterology, Hepatology and Nutrition, College of Medicine, University of Florida, Gainesville, FL, United States of America
| | - Chelsey S. Simmons
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, United States of America
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, United States of America
- Division of Cardiovascular Medicine, College of Medicine, University of Florida, Gainesville, FL, United States of America
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22
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Rubiano A, Delitto D, Han S, Gerber M, Galitz C, Trevino J, Thomas RM, Hughes SJ, Simmons CS. Viscoelastic properties of human pancreatic tumors and in vitro constructs to mimic mechanical properties. Acta Biomater 2018; 67:331-340. [PMID: 29191507 PMCID: PMC5797706 DOI: 10.1016/j.actbio.2017.11.037] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 11/08/2017] [Accepted: 11/14/2017] [Indexed: 01/18/2023]
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is almost universally fatal, in large part due to a protective fibrotic barrier generated by tumor-associated stromal (TAS) cells. This barrier is thought to promote cancer cell survival and confounds attempts to develop effective therapies. We present a 3D in vitro system that replicates the mechanical properties of the PDAC microenvironment, representing an invaluable tool for understanding the biology of the disease. Mesoscale indentation quantified viscoelastic metrics of resected malignant tumors, inflamed chronic pancreatitis regions, and histologically normal tissue. Both pancreatitis (2.15 ± 0.41 kPa, Mean ± SD) and tumors (5.46 ± 3.18 kPa) exhibit higher Steady-State Modulus (SSM) than normal tissue (1.06 ± 0.25 kPa; p < .005). The average viscosity of pancreatitis samples (63.2 ± 26.7 kPa·s) is significantly lower than that of both normal tissue (252 ± 134 kPa·s) and tumors (349 ± 222 kPa·s; p < .005). To mimic this remodeling behavior, PDAC and TAS cells were isolated from human PDAC tumors. Conditioned medium from PDAC cells was used to culture TAS-embedded collagen hydrogels. After 7 days, TAS-embedded gels in control medium reached SSM (1.45 ± 0.12 kPa) near normal pancreas, while gels maintained with conditioned medium achieved higher SSM (3.38 ± 0.146 kPa) consistent with tumors. Taken together, we have demonstrated an in vitro system that recapitulates in vivo stiffening of PDAC tumors. In addition, our quantification of viscoelastic properties suggests that elastography algorithms incorporating viscosity may be able to more accurately distinguish between pancreatic cancer and pancreatitis. STATEMENT OF SIGNIFICANCE Understanding tumor-stroma crosstalk in pancreatic ductal adenocarcinoma (PDAC) is challenged by a lack of stroma-mimicking model systems. To design appropriate models, pancreatic tissue must be characterized with a method capable of evaluating in vitro models as well. Our indentation-based characterization tool quantified the distinct viscoelastic signatures of inflamed resections from pancreatitis, tumors from PDAC, and otherwise normal tissue to inform development of mechanically appropriate engineered tissues and scaffolds. We also made progress toward a 3D in vitro system that recapitulates mechanical properties of tumors. Our in vitro model of stromal cells in collagen and complementary characterization system can be used to investigate mechanisms of cancer-stroma crosstalk in PDAC and to propose and test innovative therapies.
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Affiliation(s)
- Andres Rubiano
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, United States
| | - Daniel Delitto
- Department of Surgery, College of Medicine, University of Florida, United States
| | - Song Han
- Department of Surgery, College of Medicine, University of Florida, United States
| | - Michael Gerber
- Department of Surgery, College of Medicine, University of Florida, United States
| | - Carly Galitz
- Department of Mathematics, College of Liberal Arts and Sciences, University of Florida, United States
| | - Jose Trevino
- Department of Surgery, College of Medicine, University of Florida, United States
| | - Ryan M Thomas
- Department of Surgery, College of Medicine, University of Florida, United States
| | - Steven J Hughes
- Department of Surgery, College of Medicine, University of Florida, United States
| | - Chelsey S Simmons
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, United States; J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, United States.
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23
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Stewart DC, Rubiano A, Dyson K, Simmons CS. Mechanical characterization of human brain tumors from patients and comparison to potential surgical phantoms. PLoS One 2017; 12:e0177561. [PMID: 28582392 PMCID: PMC5459328 DOI: 10.1371/journal.pone.0177561] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/28/2017] [Indexed: 11/30/2022] Open
Abstract
While mechanical properties of the brain have been investigated thoroughly, the mechanical properties of human brain tumors rarely have been directly quantified due to the complexities of acquiring human tissue. Quantifying the mechanical properties of brain tumors is a necessary prerequisite, though, to identify appropriate materials for surgical tool testing and to define target parameters for cell biology and tissue engineering applications. Since characterization methods vary widely for soft biological and synthetic materials, here, we have developed a characterization method compatible with abnormally shaped human brain tumors, mouse tumors, animal tissue and common hydrogels, which enables direct comparison among samples. Samples were tested using a custom-built millimeter-scale indenter, and resulting force-displacement data is analyzed to quantify the steady-state modulus of each sample. We have directly quantified the quasi-static mechanical properties of human brain tumors with effective moduli ranging from 0.17–16.06 kPa for various pathologies. Of the readily available and inexpensive animal tissues tested, chicken liver (steady-state modulus 0.44 ± 0.13 kPa) has similar mechanical properties to normal human brain tissue while chicken crassus gizzard muscle (steady-state modulus 3.00 ± 0.65 kPa) has similar mechanical properties to human brain tumors. Other materials frequently used to mimic brain tissue in mechanical tests, like ballistic gel and chicken breast, were found to be significantly stiffer than both normal and diseased brain tissue. We have directly compared quasi-static properties of brain tissue, brain tumors, and common mechanical surrogates, though additional tests would be required to determine more complex constitutive models.
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Affiliation(s)
- Daniel C. Stewart
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, United States of America
| | - Andrés Rubiano
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida, United States of America
| | - Kyle Dyson
- Lillian S. Wells Department of Neurosurgery, University of Florida, Gainesville, Florida, United States of America
| | - Chelsey S. Simmons
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, United States of America
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida, United States of America
- Division of Cardiovascular Medicine, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
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Stewart DC, Rubiano A, Santisteban MM, Shenoy V, Qi Y, Pepine CJ, Raizada MK, Simmons CS. Hypertension-linked mechanical changes of rat gut. Acta Biomater 2016; 45:296-302. [PMID: 27567964 PMCID: PMC5069177 DOI: 10.1016/j.actbio.2016.08.045] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 07/01/2016] [Accepted: 08/23/2016] [Indexed: 12/15/2022]
Abstract
Hypertension is the most prevalent risk factor for cardiovascular disease caused by a persistent increase in arterial blood pressure that has lasting effects on the mechanical properties of affected tissues like myocardium and blood vessels. Our group recently discovered that gut dysbiosis is linked to hypertension in several animal models and humans; however, whether hypertension influences the gut's mechanical properties remains unknown. In this study, we evaluated the hypothesis that hypertension increases fibrosis and thus mechanical properties of the gut. A custom indentation system was used to test colon samples from Wistar Kyoto (WKY) normotensive rats and Spontaneously Hypertensive Rats (SHR). Using force-displacement data, we derived an steady-state modulus metric to quantify mechanical properties of gastrointestinal tissue. We observed that SHR proximal colon has a mean steady-state modulus almost 3 times greater than WKY control rat colon (5.11±1.58kPa and 18.17±11.45kPa, respectively). These increases were associated with increase in vascular smooth muscle cells layer and collagen deposition in the intestinal wall in the SHR. STATEMENT OF SIGNIFICANCE Mechanical characterization of biological materials can provide insight into health and disease of tissue. Recent investigations into a variety of cardiovascular pathologies show coincident changes in the microbiome and pathology of the gut. In this study, we sought to quantify changes in the gut in hypertension through mechanical characterization. Our methods and simple models for characterization, adapted from Hertz indentation models, prove useful to identify a meaningful steady-state modulus metric for small and irregular tissues from laboratory animals. Our data, for the first time, establish a stiffening of the gut wall in Spontaneously Hypertensive Rats. This observation suggests significant structural and functional changes in the gut correlate with hypertension, and future experiments are warranted to explore the specific causal relationship between dysbiosis, fibrosis, and stiffening in the gut during the development and maintenance of hypertension.
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Affiliation(s)
- Daniel C Stewart
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, United States
| | - Andrés Rubiano
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, United States
| | - Monica M Santisteban
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Vinayak Shenoy
- Department of Pharmacodynamics, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Yanfei Qi
- Division of Cardiovascular Medicine, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Carl J Pepine
- Division of Cardiovascular Medicine, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Mohan K Raizada
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Chelsey S Simmons
- J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, United States; Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, United States; Division of Cardiovascular Medicine, College of Medicine, University of Florida, Gainesville, FL, United States.
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25
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Santisteban MM, Qi Y, Zubcevic J, Kim S, Yang T, Shenoy V, Cole-Jeffrey CT, Lobaton GO, Stewart DC, Rubiano A, Simmons CS, Garcia-Pereira F, Johnson RD, Pepine CJ, Raizada MK. Hypertension-Linked Pathophysiological Alterations in the Gut. Circ Res 2016; 120:312-323. [PMID: 27799253 DOI: 10.1161/circresaha.116.309006] [Citation(s) in RCA: 319] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 10/24/2016] [Accepted: 10/31/2016] [Indexed: 12/24/2022]
Abstract
RATIONALE Sympathetic nervous system control of inflammation plays a central role in hypertension. The gut receives significant sympathetic innervation, is densely populated with a diverse microbial ecosystem, and contains immune cells that greatly impact overall inflammatory homeostasis. Despite this uniqueness, little is known about the involvement of the gut in hypertension. OBJECTIVE Test the hypothesis that increased sympathetic drive to the gut is associated with increased gut wall permeability, increased inflammatory status, and microbial dysbiosis and that these gut pathological changes are linked to hypertension. METHODS AND RESULTS Gut epithelial integrity and wall pathology were examined in spontaneously hypertensive rat and chronic angiotensin II infusion rat models. The increase in blood pressure in spontaneously hypertensive rat was associated with gut pathology that included increased intestinal permeability and decreased tight junction proteins. These changes in gut pathology in hypertension were associated with alterations in microbial communities relevant in blood pressure control. We also observed enhanced gut-neuronal communication in hypertension originating from paraventricular nucleus of the hypothalamus and presenting as increased sympathetic drive to the gut. Finally, angiotensin-converting enzyme inhibition (captopril) normalized blood pressure and was associated with reversal of gut pathology. CONCLUSIONS A dysfunctional sympathetic-gut communication is associated with gut pathology, dysbiosis, and inflammation and plays a key role in hypertension. Thus, targeting of gut microbiota by innovative probiotics, antibiotics, and fecal transplant, in combination with the current pharmacotherapy, may be a novel strategy for hypertension treatment.
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Affiliation(s)
- Monica M Santisteban
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville
| | - Yanfei Qi
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville.
| | - Jasenka Zubcevic
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville
| | - Seungbum Kim
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville
| | - Tao Yang
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville
| | - Vinayak Shenoy
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville
| | - Colleen T Cole-Jeffrey
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville
| | - Gilberto O Lobaton
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville
| | - Daniel C Stewart
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville
| | - Andres Rubiano
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville
| | - Chelsey S Simmons
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville
| | - Fernando Garcia-Pereira
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville
| | - Richard D Johnson
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville
| | - Carl J Pepine
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville
| | - Mohan K Raizada
- From the Department of Physiology and Functional Genomics, College of Medicine (M.M.S., S.K., C.T.C.-J., G.O.L., M.K.R.), Division of Cardiovascular Medicine, Department of Medicine (Y.Q., C.S.S., C.J.P.), Department of Physiological Sciences, College of Veterinary Medicine (J.Z., T.Y., F.G.-P., R.D.J.), Department of Pharmacodynamics, College of Pharmacy (V.S.), J. Crayton Pruitt Family Department of Biomedical Engineering (D.C.S., C.S.S.); Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering (A.R., C.S.S.), University of Florida, Gainesville.
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Fang X, Poulsen RR, Wang-Hu J, Shi O, Calvo NS, Simmons CS, Rivkees SA, Wendler CC. Knockdown of DNA methyltransferase 3a alters gene expression and inhibits function of embryonic cardiomyocytes. FASEB J 2016; 30:3238-55. [PMID: 27306334 PMCID: PMC5001511 DOI: 10.1096/fj.201600346r] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/31/2016] [Indexed: 12/28/2022]
Abstract
We previously found that in utero caffeine exposure causes down-regulation of DNA methyltransferases (DNMTs) in embryonic heart and results in impaired cardiac function in adulthood. To assess the role of DNMTs in these events, we investigated the effects of reduced DNMT expression on embryonic cardiomyocytes. siRNAs were used to knock down individual DNMT expression in primary cultures of mouse embryonic cardiomyocytes. Immunofluorescence staining was conducted to evaluate cell morphology. A video-based imaging assay and multielectrode array were used to assess cardiomyocyte contractility and electrophysiology, respectively. RNA-Seq and multiplex bisulfite sequencing were performed to examine gene expression and promoter methylation, respectively. At 72 h after transfection, reduced DNMT3a expression, but not DNMT1 or -3b, disrupted sarcomere assembly and decreased beating frequency, contractile movement, amplitude of field action potential, and cytosolic calcium signaling of cardiomyocytes. RNA-Seq analysis revealed that the DNMT3a-deficient cells had deactivated gene networks involved in calcium, endothelin-1, renin-angiotensin, and cardiac β-adrenergic receptor signaling, which were not inhibited by DNMT3b siRNA. Moreover, decreased methylation levels were found in the promoters of Myh7, Myh7b, Tnni3, and Tnnt2, consistent with the up-regulation of these genes by DNMT3a siRNA. These data show that DNMT3a plays an important role in regulating embryonic cardiomyocyte gene expression, morphology and function.-Fang, X., Poulsen, R. R., Wang-Hu, J., Shi, O., Calvo, N. S., Simmons, C. S., Rivkees, S. A., Wendler, C. C. Knockdown of DNA methyltransferase 3a alters gene expression and inhibits function of embryonic cardiomyocytes.
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Affiliation(s)
- Xiefan Fang
- Child Health Research Institute, Department of Pediatrics, College of Medicine, University of Florida, Gainesville, Florida, USA; and
| | - Ryan R Poulsen
- Child Health Research Institute, Department of Pediatrics, College of Medicine, University of Florida, Gainesville, Florida, USA; and
| | - John Wang-Hu
- Child Health Research Institute, Department of Pediatrics, College of Medicine, University of Florida, Gainesville, Florida, USA; and
| | - Olivia Shi
- Child Health Research Institute, Department of Pediatrics, College of Medicine, University of Florida, Gainesville, Florida, USA; and
| | - Nicholas S Calvo
- Department of Mechanical and Aerospace Engineering, College of Engineering, University of Florida, Gainesville, Florida, USA
| | - Chelsey S Simmons
- Department of Mechanical and Aerospace Engineering, College of Engineering, University of Florida, Gainesville, Florida, USA
| | - Scott A Rivkees
- Child Health Research Institute, Department of Pediatrics, College of Medicine, University of Florida, Gainesville, Florida, USA; and
| | - Christopher C Wendler
- Child Health Research Institute, Department of Pediatrics, College of Medicine, University of Florida, Gainesville, Florida, USA; and
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27
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Rocca DGD, Willenberg BJ, Qi Y, Simmons CS, Rubiano A, Ferreira LF, Huo T, Petersen JW, Ruchaya PJ, Wate PS, Wise EA, Handberg EM, Cogle CR, Batich CD, Byrne BJ, Pepine CJ. An injectable capillary-like microstructured alginate hydrogel improves left ventricular function after myocardial infarction in rats. Int J Cardiol 2016; 220:149-54. [PMID: 27379917 DOI: 10.1016/j.ijcard.2016.06.158] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 06/24/2016] [Indexed: 12/23/2022]
Abstract
BACKGROUND A new post-myocardial infarction (MI) therapy is injection of high-water-content polymeric biomaterial gels (hydrogels) into damaged myocardium to modulate cardiac negative remodeling and preserve heart function. METHODS We investigated the therapeutic potential of a novel gelatinized alginate hydrogel with a unique microstructure of uniform capillary-like channels (termed Capgel). Shortly (48h) after induced anterior MI, Sprague Dawley rats received intramyocardial injection of Capgel directly into the antero-septal wall at the infarct border zone (n=12) or no injection (n=10, controls). Echocardiograms were performed at 48h (week 0) and 4weeks (week 4) to evaluate left ventricular function. RESULTS Echocardiograms showed 27% improvement of left ventricular systolic function over time with gel injection: fractional shortening increased from 26±3% at week 0 to 33±2% at week 4 (p=0.001). Capgel was present at the injection site after 4weeks, but was minimal at 8weeks. The remaining gel was heavily populated by CD68(+) macrophages with CD206(+) clusters and blood vessels. An in vitro experiment was performed to assess Angiotensin-(1-7) released from Capgel. Angiotensin-(1-7) was released from the Capgel in a sustained manner for 90days. CONCLUSIONS Use of Capgel, a degradable, bioactive hydrogel composed of gelatinized capillary-alginate gel, appears safe for intramyocardial injection, is associated with improved left ventricular function after MI in rats, and may provide a long-term supply of Angiotensin-(1-7).
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Affiliation(s)
- Domenico G Della Rocca
- Division of Cardiovascular Medicine, Department of Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Bradley J Willenberg
- Department of Materials Science and Engineering, College of Engineering, University of Florida, Gainesville, FL, USA
| | - Yanfei Qi
- Division of Cardiovascular Medicine, Department of Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Chelsey S Simmons
- Department of Mechanical and Aerospace Engineering, College of Engineering, University of Florida, Gainesville, FL, USA
| | - Andres Rubiano
- Department of Mechanical and Aerospace Engineering, College of Engineering, University of Florida, Gainesville, FL, USA
| | - Leonardo F Ferreira
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | - Tianyao Huo
- Division of Biostatistics, Department of Epidemiology and Health Policy Research, College of Medicine, University of Florida, Gainesville, FL, USA
| | - John W Petersen
- Division of Cardiovascular Medicine, Department of Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Prashant J Ruchaya
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Prateek S Wate
- Department of Materials Science and Engineering, College of Engineering, University of Florida, Gainesville, FL, USA
| | - Elizabeth A Wise
- Division of Hematology & Oncology, Department of Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Eileen M Handberg
- Division of Cardiovascular Medicine, Department of Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Christopher R Cogle
- Division of Hematology & Oncology, Department of Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Christopher D Batich
- Department of Materials Science and Engineering, College of Engineering, University of Florida, Gainesville, FL, USA
| | - Barry J Byrne
- Division of Cellular and Molecular Therapy, Department of Pediatrics, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Carl J Pepine
- Division of Cardiovascular Medicine, Department of Medicine, College of Medicine, University of Florida, Gainesville, FL, USA.
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28
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Santisteban MM, Rubiano A, Stewart D, Yang T, Cole-Jeffrey CT, Zingler MB, Lobaton GO, Shenoy V, Zubcevic J, Simmons CS, Raizada MK. Abstract 027: Intestinal Permeability and Dysbiosis are Linked to Hypertension. Hypertension 2015. [DOI: 10.1161/hyp.66.suppl_1.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Introduction:
Emerging evidence implicates the involvement of intestinal microbiota in overall physiological homeostasis. Altered microbial composition is associated with metabolic, cardiovascular, and neurological diseases. However, the role of intestinal microbiota in blood pressure control and hypertension (HTN) remains unexplored. The present study was designed to evaluate the hypothesis that both intestinal dysbiosis and altered intestinal function are critical pathophysiological events in HTN.
Methods:
16S ribosomal DNA from fecal samples from SHR and chronic angiotensin II (Ang II, 200ng/kg/min) rat models was utilized to compare gut microbial communities between normotensive and hypertensive animals. Gut permeability was assessed by accumulation of FITC-dextran (44mg/100g BW) in the plasma 4 hours following oral feeding. Ex vivo atomic force microscopy was used to determine small intestine and colon stiffness (a measure of permeability). Tight junction gene expression was quantified by qPCR.
Results:
We observed a significant decrease in microbial richness (20%), diversity (12%), and evenness (10%) in SHR vs WKY. This was associated with an increased Firmicutes (F)/Bacteroidetes (B) ratio (4±1 vs 24±5), a hallmark of gut dysbiosis. Additionally, we observed a 95% increase in plasma FITC-dextran in SHRs (1777±428 vs 3514±563 ng/ml, p<0.05), which correlated with decreased mRNA of several tight junction genes throughout the intestine, including
Ocln
,
Tjp1
, and
Cldn4
. In addition, we found increased stiffness of both small intestine and colonic tissue, as evidenced by increased elastic modulus in SHR (small intestine: 21.2±3 vs 53.7±8 kPa, colon: 15.7±2 vs 53.4±14 kPa, p<0.05). Similar decreased microbial richness and increased F/B ratio (~2 fold) were observed in the Ang II rat model at 4 weeks. Plasma FITC-dextran began to rise by day 14 (SBP=160 mmHg), and reached maximal increase of 65% by day 21 (SBP=185 mmHg). Furthermore, colon wall stiffness was significantly increased by day 21 of Ang II infusion.
Conclusions:
These observations show that increased gut permeability/leakiness and dysbiosis is associated with HTN. They are the first to demonstrate a profound intestinal pathophysiology and microbial dysbiosis in HTN.
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Affiliation(s)
| | | | | | - Tao Yang
- Univ of Florida, Gainesville, FL
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29
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Burridge PW, Metzler SA, Nakayama KH, Abilez OJ, Simmons CS, Bruce MA, Matsuura Y, Kim P, Wu JC, Butte M, Huang NF, Yang PC. Multi-cellular interactions sustain long-term contractility of human pluripotent stem cell-derived cardiomyocytes. Am J Transl Res 2014; 6:724-735. [PMID: 25628783 PMCID: PMC4297340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 10/18/2014] [Indexed: 06/04/2023]
Abstract
Therapeutic delivery of cardiomyocytes derived from human pluripotent stem cells (hPSC-CMs) represents a novel clinical approach to regenerate the injured myocardium. However, poor survival and contractility of these cells are a significant bottleneck to their clinical use. To better understand the role of cell-cell communication in enhancing the phenotype and contractile properties of hPSC-CMs, we developed a three-dimensional (3D) hydrogel composed of hPSC-CMs, human pluripotent stem cell-derived endothelial cells (hPSC-ECs), and/or human amniotic mesenchymal stem cells (hAMSCs). The objective of this study was to examine the role of multi-cellular interactions among hPSC-ECs and hAMSCs on the survival and long-term contractile phenotype of hPSC-CMs in a 3D hydrogel. Quantification of spontaneous contractility of hPSC-CMs in tri-culture demonstrated a 6-fold increase in the area of contractile motion after 6 weeks with characteristic rhythmic contraction frequency, when compared to hPSC-CMs alone (P < 0.05). This finding was supported by a statistically significant increase in cardiac troponin T protein expression in the tri-culture hydrogel construct at 6 weeks, when compared to hPSC-CMs alone (P < 0.001). The sustained hPSC-CM survival and contractility in tri-culture was associated with a significant upregulation in the gene expression of L-type Ca(2+) ion channel, Cav1.2, and the inward-rectifier potassium channel, Kir2.1 (P < 0.05), suggesting a role of ion channels in mediating these processes. These findings demonstrate that multi-cellular interactions modulate hPSC-CM phenotype, function, and survival, and they will have important implications in engineering cardiac tissues for treatment of cardiovascular diseases.
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Affiliation(s)
- Paul W Burridge
- Stanford Cardiovascular InstitutePalo Alto, CA
- Department of Medicine, Division of Cardiovascular MedicinePalo Alto, CA
- Institute for Stem Cell Biology and Regenerative MedicinePalo Alto, CA
| | - Scott A Metzler
- Stanford Cardiovascular InstitutePalo Alto, CA
- Department of Medicine, Division of Pediatric CardiologyPalo Alto, CA
| | - Karina H Nakayama
- Stanford Cardiovascular InstitutePalo Alto, CA
- Department of Cardiothoracic SurgeryPalo Alto, CA
- Veterans Affairs Palo Alto Health Care SystemPalo Alto, CA
| | - Oscar J Abilez
- Stanford Cardiovascular InstitutePalo Alto, CA
- Department of Medicine, Division of Cardiovascular MedicinePalo Alto, CA
| | - Chelsey S Simmons
- Stanford Cardiovascular InstitutePalo Alto, CA
- Department of Mechanical Engineering, Stanford University School of EngineeringStanford, CA
- Department of Mechanical and Aerospace Engineering, University of Florida College of EngineeringGainesville, FL
| | - Marc A Bruce
- Department of Pediatrics (Immunology), Stanford University School of MedicineStanford, California, USA
| | - Yuka Matsuura
- Stanford Cardiovascular InstitutePalo Alto, CA
- Department of Medicine, Division of Cardiovascular MedicinePalo Alto, CA
| | - Paul Kim
- Stanford Cardiovascular InstitutePalo Alto, CA
- Department of Medicine, Division of Cardiovascular MedicinePalo Alto, CA
| | - Joseph C Wu
- Stanford Cardiovascular InstitutePalo Alto, CA
- Department of Medicine, Division of Cardiovascular MedicinePalo Alto, CA
- Institute for Stem Cell Biology and Regenerative MedicinePalo Alto, CA
| | - Manish Butte
- Department of Pediatrics (Immunology), Stanford University School of MedicineStanford, California, USA
| | - Ngan F Huang
- Stanford Cardiovascular InstitutePalo Alto, CA
- Department of Cardiothoracic SurgeryPalo Alto, CA
- Veterans Affairs Palo Alto Health Care SystemPalo Alto, CA
| | - Phillip C Yang
- Stanford Cardiovascular InstitutePalo Alto, CA
- Department of Medicine, Division of Cardiovascular MedicinePalo Alto, CA
- Institute for Stem Cell Biology and Regenerative MedicinePalo Alto, CA
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30
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Higgs GC, Simmons CS, Gao Y, Fried A, Park SJ, Chung C, Pruitt BL. MEMS-based shear characterization of soft hydrated samples. J Micromech Microeng 2013; 23:10.1088/0960-1317/23/8/085001. [PMID: 24187440 PMCID: PMC3811110 DOI: 10.1088/0960-1317/23/8/085001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We have designed, fabricated, calibrated and tested actuators for shear characterization to assess microscale shear properties of soft substrates. Here we demonstrate characterization of dry silicone and hydrated polyethelyne glycol. Microscale tools, including atomic force microscopes and nanoindenters, often have limited functionality in hydrated environments. While electrostatic comb-drive actuators are particularly susceptible to moisture damage, through chemical vapor deposition of hexamethyldisiloxane, we increase the hydrophobicity of our electrostatic devices to a water contact angle 90 ± 3°. With this technique we determine the effective shear stiffness of both dry and hydrated samples for a range of soft substrates. Using computational and analytical models, we compare our empirically determined effective shear stiffness with existing characterization methods, rheology and nanoindentation, for samples with shear moduli ranging from 5-320 kPa. This work introduces a new approach for microscale assessment of synthetic materials that can be used on biological materials for basic and applied biomaterials research.
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Affiliation(s)
- Gadryn C Higgs
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA 94305
- Cardiovascular Institute, Stanford University, Stanford, CA, USA 94305
| | - Chelsey S Simmons
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA 94305
- Cardiovascular Institute, Stanford University, Stanford, CA, USA 94305
| | - Yingning Gao
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA 94305
| | - Andrew Fried
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA 94305
| | - Sung-Jin Park
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA 94305
| | - Cindy Chung
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA 94305
- Department of Material Science, Stanford University, Stanford, CA, USA 94305
| | - Beth L Pruitt
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA 94305
- Cardiovascular Institute, Stanford University, Stanford, CA, USA 94305
- BioX, Stanford University, Stanford, CA, USA 94305
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31
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Lan F, Lee AS, Liang P, Sanchez-Freire V, Nguyen PK, Wang L, Han L, Yen M, Wang Y, Sun N, Abilez OJ, Hu S, Ebert AD, Navarrete EG, Simmons CS, Wheeler M, Pruitt B, Lewis R, Yamaguchi Y, Ashley EA, Bers DM, Robbins RC, Longaker MT, Wu JC. Abnormal calcium handling properties underlie familial hypertrophic cardiomyopathy pathology in patient-specific induced pluripotent stem cells. Cell Stem Cell 2013; 12:101-13. [PMID: 23290139 DOI: 10.1016/j.stem.2012.10.010] [Citation(s) in RCA: 475] [Impact Index Per Article: 43.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 08/16/2012] [Accepted: 10/12/2012] [Indexed: 12/14/2022]
Abstract
Familial hypertrophic cardiomyopathy (HCM) is a prevalent hereditary cardiac disorder linked to arrhythmia and sudden cardiac death. While the causes of HCM have been identified as genetic mutations in the cardiac sarcomere, the pathways by which sarcomeric mutations engender myocyte hypertrophy and electrophysiological abnormalities are not understood. To elucidate the mechanisms underlying HCM development, we generated patient-specific induced pluripotent stem cell cardiomyocytes (iPSC-CMs) from a ten-member family cohort carrying a hereditary HCM missense mutation (Arg663His) in the MYH7 gene. Diseased iPSC-CMs recapitulated numerous aspects of the HCM phenotype including cellular enlargement and contractile arrhythmia at the single-cell level. Calcium (Ca(2+)) imaging indicated dysregulation of Ca(2+) cycling and elevation in intracellular Ca(2+) ([Ca(2+)](i)) are central mechanisms for disease pathogenesis. Pharmacological restoration of Ca(2+) homeostasis prevented development of hypertrophy and electrophysiological irregularities. We anticipate that these findings will help elucidate the mechanisms underlying HCM development and identify novel therapies for the disease.
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Affiliation(s)
- Feng Lan
- Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, CA 94305, USA
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32
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Simmons CS, Ribeiro AJS, Pruitt BL. Formation of composite polyacrylamide and silicone substrates for independent control of stiffness and strain. Lab Chip 2013; 13:646-9. [PMID: 23287818 PMCID: PMC3605189 DOI: 10.1039/c2lc41110e] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Cells that line major tissues in the body such as blood vessels, lungs and gastrointestinal tract experience deformation from mechanical strain with our heartbeat, breathing, and other daily activities. Tissues also remodel in both development and disease, changing their mechanical properties. Taken together, cells can experience vastly different mechanical cues resulting from the combination of these interdependent stimuli. To date, most studies of cellular mechanotransduction have been limited to assays in which variations in substrate stiffness and strain were not combined. Here, we address this technological gap by implementing a method that can simultaneously tune both substrate stiffness and mechanical strain. Substrate stiffness is controlled with different monomer and crosslinker ratios during polyacrylamide gel polymerization, and strain is transferred from the underlying silicone platform when stretched. We demonstrate this platform with polyacrylamide gels with elastic moduli at 6 kPa and 20 kPa in combination with two different silicone formulations. The gels remain attached with up to 50% applied strains. To validate strain transfer through the gels into cells, we employ particle-tracking methods and observe strain transmission via cell morphological changes.
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Affiliation(s)
- Chelsey S. Simmons
- Department of Mechanical Engineering and Cardiovascular Institute, Stanford University
| | | | - Beth L. Pruitt
- Department of Mechanical Engineering and Cardiovascular Institute, Stanford University
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33
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Abstract
The heart is a complex integrated system that leverages mechanoelectrical signals to synchronize cardiomyocyte contraction and push blood throughout the body. The correct magnitude, timing, and distribution of these signals is critical for proper functioning of the heart; aberrant signals can lead to acute incidents, long-term pathologies, and even death. Due to the heart's limited regenerative capacity and the wide variety of pathologies, heart disease is often studied in vitro. However, it is difficult to accurately replicate the cardiac environment outside of the body. Studying the biophysiology of the heart in vitro typically consists of studying single cells in a tightly controlled static environment or whole tissues in a complex dynamic environment. Micro-electromechanical systems (MEMS) allow us to bridge these two extremes by providing increasing complexity for cell culture without having to use a whole tissue. Here, we carefully describe the electromechanical environment of the heart and discuss MEMS specifically designed to replicate these stimulation modes. Strengths, limitations and future directions of various designs are discussed for a variety of applications.
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Affiliation(s)
- Chelsey S Simmons
- Department of Mechanical Engineering, Stanford University, Stanford, California, USA
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34
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Simmons CS, Sim JY, Baechtold P, Gonzalez A, Chung C, Borghi N, Pruitt BL. Integrated strain array for cellular mechanobiology studies. J Micromech Microeng 2011; 21:54016-54025. [PMID: 21857773 PMCID: PMC3156674 DOI: 10.1088/0960-1317/21/5/054016] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We have developed an integrated strain array for cell culture enabling high-throughput mechano-transduction studies. Biocompatible cell culture chambers were integrated with an acrylic pneumatic compartment and microprocessor-based control system. Each element of the array consists of a deformable membrane supported by a cylindrical pillar within a well. For user-prescribed waveforms, the annular region of the deformable membrane is pulled into the well around the pillar under vacuum, causing the pillar-supported region with cultured cells to be stretched biaxially. The optically clear device and pillar-based mechanism of operation enables imaging on standard laboratory microscopes. Straightforward fabrication utilizes off-the-shelf components, soft lithography techniques in polydimethylsiloxane, and laser ablation of acrylic sheets. Proof of compatibility with basic biological assays and standard imaging equipment were accomplished by straining C2C12 skeletal myoblast cells on the device for 6 hours. At higher strains, cells and actin stress fibers realign with a circumferential preference.
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Affiliation(s)
- C S Simmons
- Department of Mechanical Engineering, Stanford University, Stanford, CA
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35
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Gangadharam PR, Simmons CS, Stager CE. Phage typing of mycobacteria using paper discs. Am Rev Respir Dis 1978; 118:148-50. [PMID: 354442 DOI: 10.1164/arrd.1978.118.1.148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The suitability of phage-impregnated paper discs for the phage typing of mycobacteria was studied. The relevance of the routine test dilution, the volume of the phage used, the mode of incubation, and the effect of prolonged storage of phage-impregnated paper discs were considered. By using paper discs, each impregnated with one of 5 different mycobacteriophages (BG1, BK1, G37, CRI-3 and LG) that lyse Mycobacterium smegmatis 607B, it was determined that 100 x the routine test dilution in a volume of at least 20 microliter was required for phage lysis. Soaked and dried paper discs produced larger areas of lysis than those with 20-microliter volumes. Soaked discs were found to be stable even after storage for 8 weeks at 4 degrees C.
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36
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Knight AW, Simmons MA, Simmons CS. A phenomenological approach to the growth of the winter stonefly, Taeniopteryx nivalis (Fitch) (Plecoptera:Taeniopterygidae). Growth 1976; 40:343-67. [PMID: 1010390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The growth and respiration of a univoltine winter stonefly, Taeniopteryx nivalis (Fitch) was evaluated over a period which encompassed both the nymphal and adult life stages. A simple allometry did not describe the relation found between weight and respiration during the evaluated growth period. The relation between growth and respiration of T. nivalis was described by an extension of the stochastic growth model of Zotina and Zotin, which enables one to determine the biological age of an organism by utilizing only weight and respiration. From a comparison of the general Bertalanffy growth model with the extended stochastic model, the growth of T. nivalis up to the last instar could be ascribed entirely to anabolic processes; differentiation probably accounts for the observed relation between weight and respiration during the last nymphal instar.
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