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Applewhite B, Andreopoulos F, Vazquez-Padron RI. Periadventitial biomaterials to improve arteriovenous fistula and graft outcomes. J Vasc Access 2024; 25:713-727. [PMID: 36349745 DOI: 10.1177/11297298221135621] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024] Open
Abstract
Periadventitial biomaterials have been employed for nearly three decades to promote adaptive venous remodeling following hemodialysis vascular access creation in preclinical models and clinical trials. These systems are predicated on the combination of scaffolds, hydrogels, and/or particles with therapeutics (small molecules, proteins, genes, and cells) to prevent venous stenosis and subsequent maturation failure. Periadventitial biomaterial therapies have evolved from simple drug delivery vehicles for traditional drugs to more thoughtful designs tailored to the pathophysiology of access failure. The emergence of tissue engineering strategies and gene therapies are another exciting new direction. Despite favorable results in experimental and preclinical studies, no periadventitial therapy has been clinically approved to improve vascular access outcomes. After conducting an exhaustive review of the literature, we identify the seminal studies and clinical trials that utilize periadventitial biomaterials and discuss the key features of each biomaterial format and their respective shortcomings as they pertain to access maturation. This review provides a foundation from which clinicians, surgeons, biologists, and engineers can refer to and will hopefully inspire thoughtful, translatable treatments to finally address access failure.
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Affiliation(s)
- Brandon Applewhite
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, FL, USA
| | - Fotios Andreopoulos
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, FL, USA
| | - Roberto I Vazquez-Padron
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, FL, USA
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Self-Powered and Flexible Triboelectric Sensors with Oblique Morphology towards Smart Swallowing Rehabilitation Monitoring System. MATERIALS 2022; 15:ma15062240. [PMID: 35329692 PMCID: PMC8954625 DOI: 10.3390/ma15062240] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 03/06/2022] [Accepted: 03/14/2022] [Indexed: 02/01/2023]
Abstract
With aging, disability of the body can easily occur because the function of the body is degraded. Especially, swallowing disorder is regarded as a crucial issue because patients cannot obtain the nutrients from food by swallowing it. Hence, the rehabilitation of swallowing disorder is urgently required. However, the conventional device for swallowing rehabilitation has shown some limitations due to its external power source and internal circuit. Herein, a self-powered triboelectric nanogenerator for swallowing rehabilitation (TSR) is proposed. To increase the electrical output and pressure sensitivity of the TSR, the tilted reactive ion etching is conducted and the electrical output and pressure sensitivity are increased by 206% and 370%, respectively. The effect of the tilted reactive ion etching into the electrical output generated from the TSR is systematically analyzed. When the tongue is pressing, licking, and holding the TSR, each motion is successfully detected through the proposed TSR. Based on these results, the smart swallowing rehabilitation monitoring system (SSRMS) is implemented as the application and the SSRMS could successfully detect the pressing by the tongue. Considering these results, the SSRMS can be expected to be utilized as a promising smart swallowing rehabilitation monitoring system in near future.
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Zhu Q, Ye P, Wang J, Chang Z. Inhibition of edge stenosis of endografts in swine iliac arteries by a novel endograft with biodegradable coating at both ends. JVS Vasc Sci 2021; 2:207-218. [PMID: 34761240 PMCID: PMC8567203 DOI: 10.1016/j.jvssci.2021.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 05/14/2021] [Indexed: 11/28/2022] Open
Abstract
Objective This study evaluated the effectiveness and safety of a novel endograft with a biodegradable coating at both ends in preventing edge stenosis in swine iliac arteries. The biodegradable coating was composed of polylactide and paclitaxel. Methods Four types of endograft were implanted in the iliac arteries of healthy swine: an endograft without coating (control group) and endografts with polylactide and paclitaxel coating containing 0.1, 0.3, or 3.6 μg/mm2 of paclitaxel. The edge stenosis of these endografts in swine iliac arteries was assessed using angiographic image data at 30, 90, and 180 days after the operation. After terminal angiography, histologic evaluation of the treated arteries was performed. The treated sections of iliac arteries and blood samples were obtained at 1, 7, 30, 90, and 180 days for pharmacokinetic analysis. Results The results of angiographic and histologic evaluation demonstrated that intimal hyperplasia contributed to edge stenosis and polylactide-paclitaxel coating effectively inhibited edge stenosis. At 30 days, edge stenosis was observed at both the proximal and distal edges of the endograft without coating. At 90 days, edge stenosis was detected for the endograft coated with 0.1 μg/mm2 paclitaxel, and ectasia dilation occurred at the proximal and distal edges of the endograft coated with 3.6 μg/mm2 paclitaxel. No edge stenosis or other adverse effects were observed at 90 and 180 days for the endograft coated with 0.3 μg/mm2 paclitaxel. In addition, for the endograft coated with 0.3 μg/mm2 paclitaxel, a pharmacokinetic analysis showed that the paclitaxel concentration of treated segments decreased from 14 264 ± 1020 ng/g at day 1 to 80 ± 70 ng/g at day 90, and 20 ± 40 ng/g at day 180. The plasma paclitaxel concentration was low at day 1 and no longer detected after 7 days. Conclusions Polylactide and paclitaxel coating containing 0.3 μg/mm2 paclitaxel at both ends of endografts effectively and safely inhibits edge stenosis in swine iliac arteries.
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Affiliation(s)
- Qing Zhu
- Shanghai Institute for Minimally Invasive Therapy, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, PR China.,Shanghai MicroPort Endovascular MedTech (Group) Co., Ltd, Shanghai, PR China
| | - Ping Ye
- Shanghai Institute for Minimally Invasive Therapy, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, PR China
| | - Jinyao Wang
- Shanghai MicroPort Endovascular MedTech (Group) Co., Ltd, Shanghai, PR China
| | - Zhaohua Chang
- Shanghai Institute for Minimally Invasive Therapy, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, PR China.,Shanghai MicroPort Endovascular MedTech (Group) Co., Ltd, Shanghai, PR China
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Zhao C, Zuckerman ST, Cai C, Kilari S, Singh A, Simeon M, von Recum HA, Korley JN, Misra S. Periadventitial Delivery of Simvastatin-Loaded Microparticles Attenuate Venous Neointimal Hyperplasia Associated With Arteriovenous Fistula. J Am Heart Assoc 2020; 9:e018418. [PMID: 33283594 PMCID: PMC7955373 DOI: 10.1161/jaha.120.018418] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background Venous neointimal hyperplasia and venous stenosis (VS) formation can result in a decrease in arteriovenous fistula (AVF) patency in patients with end‐stage renal disease. There are limited therapies that prevent VNH/VS. Systemic delivery of simvastatin has been shown to reduce VNH/VS but local delivery may help decrease the side effects associated with statin use. We determined if microparticles (MP) composed of cyclodextrins loaded with simvastatin (MP‐SV) could reduce VS/VNH using a murine arteriovenous fistula model with chronic kidney disease. Methods and Results Male C57BL/6J mice underwent nephrectomy to induce chronic kidney disease. Four weeks later, an arteriovenous fistula was placed and animals were randomized to 3 groups: 20 μL of PBS or 20 μL of PBS with 16.6 mg/mL of either MP or MP‐SV. Animals were euthanized 3 days later and the outflow veins were harvested for quantitative reverse transcriptase–polymerase chain reaction analysis and 28 days later for immunohistochemistical staining with morphometric analysis. Doppler ultrasound was performed weekly. Gene expression of vascular endothelial growth factor‐A (Vegf‐A), matrix metalloproteinase‐9 (Mmp‐9), transforming growth factor beta 1 (Tgf‐β1), and monocyte chemoattractant protein‐1 (Mcp‐1) were significantly decreased in MP‐SV treated vessels compared with controls. There was a significant decrease in the neointimal area, cell proliferation, inflammation, and fibrosis, with an increase in apoptosis and peak velocity in MP‐SV treated outflow veins. MP‐SV treated fibroblasts when exposed to hypoxic injury had decreased gene expression of Vegf‐A and Mmp‐9. Conclusions In experimental arteriovenous fistulas, periadventitial delivery of MP‐SV decreased gene expression of Vegf‐A, Mmp‐9, Tgf‐β1 and Mcp‐1, VNH/VS, inflammation, and fibrosis.
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Affiliation(s)
- Chenglei Zhao
- Vascular and Interventional Radiology Translational Laboratory Department of Radiology Mayo Clinic Rochester MN.,Department of Vascular Surgery The Second Xiangya HospitalCentral South University Changsha Hunan China
| | | | - Chuanqi Cai
- Vascular and Interventional Radiology Translational Laboratory Department of Radiology Mayo Clinic Rochester MN.,Department of Vascular Surgery Union Hospital Tongji Medical CollegeHuazhong University of Science and Technology Wuhan China
| | - Sreenivasulu Kilari
- Vascular and Interventional Radiology Translational Laboratory Department of Radiology Mayo Clinic Rochester MN
| | - Avishek Singh
- Vascular and Interventional Radiology Translational Laboratory Department of Radiology Mayo Clinic Rochester MN
| | - Michael Simeon
- Vascular and Interventional Radiology Translational Laboratory Department of Radiology Mayo Clinic Rochester MN
| | - Horst A von Recum
- Department of Biomedical Engineering Case Western Reserve University Cleveland OH
| | | | - Sanjay Misra
- Vascular and Interventional Radiology Translational Laboratory Department of Radiology Mayo Clinic Rochester MN.,Department of Biochemistry and Molecular Biology Mayo Clinic Rochester MN
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Kwon SH, Li L, Terry CM, Shiu YT, Moos PJ, Milash BA, Cheung AK, Blumenthal DK. Differential gene expression patterns in vein regions susceptible versus resistant to neointimal hyperplasia. Physiol Genomics 2018; 50:615-627. [PMID: 29750603 PMCID: PMC6139633 DOI: 10.1152/physiolgenomics.00082.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 05/04/2018] [Accepted: 05/07/2018] [Indexed: 12/14/2022] Open
Abstract
Arteriovenous hemodialysis graft (AVG) stenosis results in thrombosis and AVG failure, but prevention of stenosis has been unsuccessful due in large part to our limited understanding of the molecular processes involved in neointimal hyperplasia (NH) formation. AVG stenosis develops chiefly as a consequence of highly localized NH formation in the vein-graft anastomosis region. Surprisingly, the vein region just downstream of the vein-graft anastomosis (herein termed proximal vein region) is relatively resistant to NH. We hypothesized that the gene expression profiles of the NH-prone and NH-resistant regions will be different from each other after graft placement, and analysis of their genomic profiles may yield potential therapeutic targets to prevent AVG stenosis. To test this, we evaluated the vein-graft anastomosis (NH-prone) and proximal vein (NH-resistant) regions in a porcine model of AVG stenosis with a porcine microarray. Gene expression changes in these two distinct vein regions, relative to the gene expression in unoperated control veins, were examined at early (5 days) and later (14 days) time points following graft placement. Global genomic changes were much greater in the NH-prone region than in the NH-resistant region at both time points. In the NH-prone region, genes related to regulation of cell proliferation and osteo-/chondrogenic vascular remodeling were most enriched among the significantly upregulated genes, and genes related to smooth muscle phenotype were significantly downregulated. These results provide insights into the spatial and temporal genomic modulation underlying NH formation in AVG and suggest potential therapeutic strategies to prevent and/or limit AVG stenosis.
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Affiliation(s)
- Sun Hyung Kwon
- Department of Pharmacology and Toxicology, University of Utah , Salt Lake City, Utah
| | - Li Li
- Department of Internal Medicine, Division of Nephrology and Hypertension, University of Utah , Salt Lake City, Utah
| | - Christi M Terry
- Department of Internal Medicine, Division of Nephrology and Hypertension, University of Utah , Salt Lake City, Utah
| | - Yan-Ting Shiu
- Department of Internal Medicine, Division of Nephrology and Hypertension, University of Utah , Salt Lake City, Utah
| | - Philip J Moos
- Department of Pharmacology and Toxicology, University of Utah , Salt Lake City, Utah
| | - Brett A Milash
- Bioinformatics Shared Resource, University of Utah, Huntsman Cancer Institute , Salt Lake City, Utah
| | - Alfred K Cheung
- Department of Internal Medicine, Division of Nephrology and Hypertension, University of Utah , Salt Lake City, Utah
- Medical Service, Veterans Affairs Salt Lake City Healthcare System, Salt Lake City, Utah
- Department of Nephrology, The Second Xiangya Hospital, Central South University , Changsha, Hunan , People's Republic of China
| | - Donald K Blumenthal
- Department of Pharmacology and Toxicology, University of Utah , Salt Lake City, Utah
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Schleimer K, Jalaie H, Afify M, Woitok A, Barbati ME, Hoeft K, Jacobs M, Tolba RH, Steitz J. Sheep models for evaluation of novel patch and prosthesis material in vascular surgery: tips and tricks to avoid possible pitfalls. Acta Vet Scand 2018; 60:42. [PMID: 29976210 PMCID: PMC6034312 DOI: 10.1186/s13028-018-0397-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 06/27/2018] [Indexed: 11/25/2022] Open
Abstract
Background In vascular surgery, novel synthetic prosthesis materials for patch-angioplasties, interpositions, bypasses and shunts are continuously under development and optimization. The characteristics of an ideal vascular prosthesis would display long-term patency, biocompatibility, durability, low porosity, lack of stich hole bleeding, ease of handling, kink resistance, infection resistance and reasonable costs. The aim of this study was to establish and report a reliable sheep model including potential pitfalls where those parameters could be analyzed. Before surgery, sheep were acclimatized for 4–8 weeks, during which parasite infections were treated and blood and serum parameters monitored. Twenty-four sheep underwent surgery, and carotid patch-angioplasties (n = 12), graft interpositions (n = 6) or arteriovenous prosthetic shunts (n = 6) were implanted. Half of the animals in each group were sacrificed after 2 weeks and the other half after 8 weeks. The implants were analyzed for patency, endothelialization, thrombogenicity and biocompatibility by clinical observation, blood flow measurement and pathological and histopathological (H&E, EvG) as well as immunohistochemical (Ki67, CD31) evaluations. Results Health monitoring of the sheep revealed a parasitic burden with endoparasites in all animals. Some animals showed thereby infestations in the bile duct causing fibrotic cholangitis with calcifications in the liver. In addition, sarcosporidia were detected in histopathological specimen of the heart in all animals. Parasitic burden correlated with blood counts and serum bilirubin levels. Both were significantly reduced by albendazole treatment within the acclimatization time. Patches, interposition grafts, and straight shunts were successfully implanted bilaterally in all animals. The total average operation time was 136 ± 21 min. Most animals (23/24) showed good patency rates and general condition after implantation. Pathological and histopathological/immunohistochemical analyses were suitable to determine thrombogenicity, endothelialization, cellular/fibroblastic proliferation, biocompatibility, inflammatory cell infiltration, and thickness of neointima in the prosthesis material. Conclusions We have developed a suitable experimental protocol with standardized and successful anesthesia- and surgical-procedures for patch-angioplasty, graft interposition, and arteriovenous prosthetic shunts. This sheep model allows testing of new prosthetic materials for biocompatibility, thrombogenicity, and endothelialization.
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Mylonaki I, Allémann É, Saucy F, Haefliger JA, Delie F, Jordan O. Perivascular medical devices and drug delivery systems: Making the right choices. Biomaterials 2017; 128:56-68. [PMID: 28288349 DOI: 10.1016/j.biomaterials.2017.02.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 02/13/2017] [Accepted: 02/26/2017] [Indexed: 12/31/2022]
Abstract
Perivascular medical devices and perivascular drug delivery systems are conceived for local application around a blood vessel during open vascular surgery. These systems provide mechanical support and/or pharmacological activity for the prevention of intimal hyperplasia following vessel injury. Despite abundant reports in the literature and numerous clinical trials, no efficient perivascular treatment is available. In this review, the existing perivascular medical devices and perivascular drug delivery systems, such as polymeric gels, meshes, sheaths, wraps, matrices, and metal meshes, are jointly evaluated. The key criteria for the design of an ideal perivascular system are identified. Perivascular treatments should have mechanical specifications that ensure system localization, prolonged retention and adequate vascular constriction. From the data gathered, it appears that a drug is necessary to increase the efficacy of these systems. As such, the release kinetics of pharmacological agents should match the development of the pathology. A successful perivascular system must combine these optimized pharmacological and mechanical properties to be efficient.
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Affiliation(s)
- Ioanna Mylonaki
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, rue Michel Servet 1, CH-1211 Geneva 4, Switzerland
| | - Éric Allémann
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, rue Michel Servet 1, CH-1211 Geneva 4, Switzerland
| | - François Saucy
- Department of Vascular Surgery, Lausanne University Hospital, rue du Bugnon 46, CH-1011 Lausanne, Switzerland
| | - Jacques-Antoine Haefliger
- Department of Vascular Surgery, Lausanne University Hospital, rue du Bugnon 46, CH-1011 Lausanne, Switzerland
| | - Florence Delie
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, rue Michel Servet 1, CH-1211 Geneva 4, Switzerland
| | - Olivier Jordan
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, rue Michel Servet 1, CH-1211 Geneva 4, Switzerland.
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8
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Mylonaki I, Strano F, Deglise S, Allémann E, Alonso F, Corpataux JM, Dubuis C, Haefliger JA, Jordan O, Saucy F, Delie F. Perivascular sustained release of atorvastatin from a hydrogel-microparticle delivery system decreases intimal hyperplasia. J Control Release 2016; 232:93-102. [DOI: 10.1016/j.jconrel.2016.04.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 04/13/2016] [Accepted: 04/14/2016] [Indexed: 12/26/2022]
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9
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Kwon SH, Li L, He Y, Tey CS, Li H, Zhuplatov I, Kim SJ, Terry CM, Blumenthal DK, Shiu YT, Cheung AK. Prevention of Venous Neointimal Hyperplasia by a Multitarget Receptor Tyrosine Kinase Inhibitor. J Vasc Res 2016; 52:244-256. [PMID: 26788996 DOI: 10.1159/000442977] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 12/01/2015] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND/AIMS Venous neointimal hyperplasia (NH) is the predominant cause of stenosis in hemodialysis arteriovenous grafts (AVG), but there is currently no clinically used therapy to prevent NH. METHODS A porcine AVG model was used to identify potential pharmacological targets to prevent NH. Sunitinib, a broad-spectrum tyrosine kinase inhibitor, was examined as a potential anti-NH drug utilizing in vitro and ex vivo models. RESULTS In an in vivo porcine model, PDGF, VEGF and their receptors PDGFR-α and VEGFR-2 were upregulated at the venous anastomosis within 2 weeks after AVG placement, with NH development by 4 weeks. Sunitinib inhibited PDGF-stimulated proliferation, migration, phosphorylation of MAPK and PI3K/Akt proteins and changes in the expression of cell-cycle regulatory proteins in vascular smooth-muscle cells as well as VEGF-stimulated endothelial cell proliferation in vitro. In an ex vivo model, significant NH was observed in porcine vein segments perfused for 12 days under pathological shear stress. Sunitinib (100 nM) inhibited NH formation, with the intima-to-lumen area ratio decreasing from 0.45 ± 0.25 to 0.04 ± 0.02 (p < 0.05) with treatment. CONCLUSION These findings demonstrate sunitinib to be a potential NH-preventive drug as well as the utility of an ex vivo model to investigate pharmacotherapies under pathophysiological flow conditions.
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Affiliation(s)
- Sun Hyung Kwon
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, U.S.A
| | - Li Li
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Yuxia He
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Chieh Sheng Tey
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Huan Li
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Ilya Zhuplatov
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Seung-Jung Kim
- School of Medicine, Division of Nephrology, Ewha Womans University, Seoul, South Korea
| | - Christi M Terry
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Donald K Blumenthal
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, U.S.A
| | - Yan-Ting Shiu
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A
| | - Alfred K Cheung
- Division of Nephrology & Hypertension, Department of Medicine, University of Utah, Salt Lake City, Utah, U.S.A.,Medical Service, Veterans Affairs Salt Lake City Healthcare System, Salt Lake City, Utah, U.S.A
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Zheng C, Zhou Y, Huang C, Zhang Z, Liu YI, Xu Y. Establishment of a rat autogenous arteriovenous fistula model following 5/6 nephrectomy. Exp Ther Med 2015; 10:219-224. [PMID: 26170938 DOI: 10.3892/etm.2015.2451] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 03/05/2015] [Indexed: 12/30/2022] Open
Abstract
The aim of this study was to establish a stable rat model of autogenous arteriovenous fistula (AVF) with chronic renal function insufficiency. Forty Sprague-Dawley rats were randomly divided into an experimental group (n=20) and sham surgery group (n=20) and a 5/6 nephrectomy model was established in the rats. One week later, in the experimental group, the ipsilateral caroid artery was inserted into the external jugular vein by a cuff technique to establish a carotid arteriovenous fistula; in the sham group, the external jugular vein and carotid artery were dissociated. At 7 and 28 days following the establishment of the AVF, the renal functions of the two groups were measured. Hematoxylin and eosin staining and double collagen and elastin staining were conducted to evaluate the area of intimal hyperplasia in the external jugular vein, and the expression of α-smooth muscle actin in the vein was investigated by immunohistochemistry. The creatinine and urea nitrogen levels in the experimental group at each time-point were significantly higher than those in the sham surgery group (P<0.05). The intimal hyperplasia of the external jugular vein of the experimental group was increased significantly compared with that in the sham group at each time-point (P<0.05). The model, which is easy to establish and simple to master, provides a new and feasible experimental method for the study of intimal hyperplasia associated with autogenous AVF in chronic renal insufficiency, and is worthy of wider use.
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Affiliation(s)
- Chenfei Zheng
- Department of Nephrology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Ying Zhou
- Department of Nephrology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Chaoxing Huang
- Department of Nephrology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Zhouchang Zhang
- Department of Nephrology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Y I Liu
- Department of Nephrology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Yulan Xu
- Department of Nephrology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
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11
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Terry CM, Carlson ML, He Y, Ulu A, Morisseau C, Blumenthal DK, Hammock BD, Cheung AK. Aberrant soluble epoxide hydrolase and oxylipin levels in a porcine arteriovenous graft stenosis model. J Vasc Res 2014; 51:269-82. [PMID: 25196102 DOI: 10.1159/000365251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 04/23/2014] [Indexed: 11/19/2022] Open
Abstract
Synthetic arteriovenous grafts (AVGs) used for hemodialysis frequently fail due to the development of neointimal hyperplasia (NH) at the vein-graft anastomosis. Inflammation and smooth-muscle cell (SMC) and myofibroblast proliferation and migration likely play an important role in the pathogenesis of NH. Epoxyeicosatrienoic acids (EETs), the products of the catabolism of arachidonic acid by cytochrome P450 enzymes, possess anti-inflammatory, antiproliferative, antimigratory and vasodilatory properties that should reduce NH. The degradation of vasculoprotective EETs is catalyzed by the enzyme, soluble epoxide hydrolase (sEH). sEH upregulation may thus contribute to NH development by the enhanced removal of vasculoprotective EETs. In this study, sEH, cytochrome P450 and EETs were examined after AVG placement in a porcine model to explore their potential roles in AVG stenosis. Increased sEH protein expression, decreased P450 epoxygenase activity and dysregulation of 5 oxylipin mediators were observed in the graft-venous anastomotic tissues when compared to control veins. Pharmacological inhibitors of sEH decreased the growth factor-induced migration of SMCs and fibroblasts, although they had no significant effect on the proliferation of these cells. These results provide insights on epoxide biology in vascular disorders and a rationale for the development of novel pharmacotherapeutic strategies to prevent AVG failure due to NH and stenosis.
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Affiliation(s)
- Christi M Terry
- Division of Nephrology and Hypertension, University of Utah, Utah, USA
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12
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Terry CM, Dember LM. Novel therapies for hemodialysis vascular access dysfunction: myth or reality? Clin J Am Soc Nephrol 2013; 8:2202-12. [PMID: 24235283 DOI: 10.2215/cjn.07360713] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hemodialysis vascular access dysfunction is a major source of morbidity for patients with ESRD. Development of effective approaches to prevent and treat vascular access failure requires an understanding of the underlying mechanisms, suitable models for preclinical testing, systems for targeted delivery of interventions to maximize efficacy and minimize toxicity, and rigorous clinical trials that use appropriate outcome measures. This article reviews the substantial progress and ongoing challenges in developing novel treatments for arteriovenous vascular access failure and focuses on localized rather than systemic interventions.
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Affiliation(s)
- Christi M Terry
- Division of Nephrology and Hypertension, University of Utah, Salt Lake City, Utah, †Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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13
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Gessaroli M, Bombardi C, Giunti M, Bacci ML. Prevention of neointimal hyperplasia associated with modified stretch expanded polytetrafluoroethylene hemodialysis grafts (Gore) in an experimental preclinical study in swine. J Vasc Surg 2012; 55:192-202. [DOI: 10.1016/j.jvs.2011.07.076] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 07/15/2011] [Accepted: 07/15/2011] [Indexed: 11/29/2022]
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14
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In vivo PEG modification of vascular surfaces for targeted delivery. J Vasc Surg 2011; 55:1087-95. [PMID: 22169667 DOI: 10.1016/j.jvs.2011.09.081] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 09/23/2011] [Accepted: 09/24/2011] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Thrombosis and restenosis remain problematic for many intravascular procedures. Previously, it has been demonstrated that modifying an injured vascular surface with a protein-reactive polymer could block undesirable platelet deposition. As an added benefit, it would be advantageous if one could target therapeutics to the injured site. This study investigates a site-specific delivery system to target microspheres to vascular surfaces modified with a reactive polyethylene glycol tagged with biotin. METHODS Rabbit femoral arteries were injured with a 2F embolectomy catheter. Modification of the vascular surface was achieved using a channeled balloon catheter or small-diameter tube. Microspheres were injected intravenously through catheterization of the ear vein. Polymer modification on the injured surface and delivery of microspheres was quantified using epifluorescence microscopy at 0, 24, 48, and 72 hours. RESULTS Polymer modification of the vascular surface could be achieved using a channeled drug delivery catheter or small-diameter tube with similar results. Maximum polymer coverage occurred at 0 hours and decreased to 85% maximal at 24 hours, 72% at 48 hours, and 67% at 72 hours. The initial number of microspheres per mm(2) binding to modified, injured arteries was 304 versus 141 for the unmodified, damaged control (P < .01). At subsequent times, the number of adherent microspheres to modified, injured arteries decreased by 50%, 70%, and 84% at 24, 48, and 72 hours, respectively; while nonspecific binding to unmodified, injured arteries quickly decreased by 93%. Initial microsphere binding to modified, healthy arteries was 153 microspheres/mm(2) as opposed to 26 microspheres/mm(2) for the unmodified, healthy controls (P < .01). CONCLUSIONS Chemical modification of injured vessels following intravascular procedures can be readily accomplished in vivo to create a substrate for targeted delivery systems. As a proof of concept, targeted microspheres preferentially adhered to polymer-modified surfaces as opposed to injured, unmodified, or healthy vascular surfaces.
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Dixon BS, Beck GJ, Dember LM, Vazquez MA, Greenberg A, Delmez JA, Allon M, Himmelfarb J, Hu B, Greene T, Radeva MK, Davidson IJ, Ikizler TA, Braden GL, Lawson JH, Cotton JR, Kusek JW, Feldman HI. Use of aspirin associates with longer primary patency of hemodialysis grafts. J Am Soc Nephrol 2011; 22:773-81. [PMID: 21415156 DOI: 10.1681/asn.2010060582] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Extended-release dipyridamole plus low-dose aspirin (ERDP/ASA) prolongs primary unassisted graft patency of newly created hemodialysis arteriovenous grafts, but the individual contributions of each component are unknown. Here, we analyzed whether use of aspirin at baseline associated with primary unassisted graft patency among participants in a randomized trial that compared ERDP/ASA and placebo in newly created grafts. We used Cox proportional hazards regression, adjusting for prespecified baseline comorbidities and covariates. Of all participants, 43% reported use of aspirin at baseline; of these, 82% remained on nonstudy aspirin (i.e., excluding ERDP/ASA) at 1 year. After 1 year of follow-up, the incidence of primary unassisted patency among participants using aspirin at baseline was 30% (95% CI: 24 to 35%) and among those not using aspirin was 23% (95% CI: 18 to 27%). Use of aspirin at baseline associated with a dose-dependent prolongation of primary unassisted graft patency that approached statistical significance (adjusted HR, 0.83; 95% CI: 0.68 to 1.01; P=0.06). Use of aspirin at baseline did not associate with prolongation of cumulative graft patency or participant survival. In conclusion, use of aspirin associates with a trend toward longer primary unassisted patency of newly placed hemodialysis grafts similar to that observed for ERDP/ASA.
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Affiliation(s)
- Bradley S Dixon
- Division of Nephrology, University of Iowa College of Medicine, E-300D GH, 200 Hawkins Drive, Iowa City, IA 52242-1081, USA.
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Owen SC, Li H, Sanders WG, Cheung AK, Terry CM. Correlation of tissue drug concentrations with in vivo magnetic resonance images of polymer drug depot around arteriovenous graft. J Control Release 2010; 146:23-30. [PMID: 20457189 DOI: 10.1016/j.jconrel.2010.05.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 03/18/2010] [Accepted: 05/04/2010] [Indexed: 12/15/2022]
Abstract
Sustained delivery of anti-proliferative drugs to the perivascular area using an injectable polymeric platform is a strategy to inhibit vascular hyperplasia and stenosis. In this study, the concentrations of sirolimus in vascular tissues were evaluated after delivery using an injectable platform made of poly(lactic-co-glycolic acid)-polyethylene glycol-poly(lactic-co-glycolic acid) (PLGA-PEG-PLGA). In order to optimize the drug release profile, the effect of two solvents or solid loading of the sirolimus into the polymer gel was first examined in vitro. The early release was slower with loading of dry drug into the polymer, compared to drug dissolution in solvents. Dry sirolimus was therefore used to load the polymer and applied to the perivascular surface of the graft-venous anastomosis at the time of surgical placement of a carotid-jugular synthetic hemodialysis graft in a porcine model. This was replenished by ultrasound-guided injection of additional drug-laden polymer at one, two and three weeks post-operatively. Magnetic resonance imaging (MRI) using pulse sequences specifically designed for optimal detection of the polymeric gel showed that the polymer injected post-operatively remained at the juxta-anastomotic perivascular site at two weeks. Sirolimus was extracted from various segments of the juxta-anastomotic tissues and the drug concentrations were determined using HPLC MS/MS. Tissue sirolimus concentrations at one and two weeks were highest near the venous anastomosis, which were approximately 100- to 500-fold greater than the concentrations necessary to inhibit vascular smooth muscle cell proliferation in vitro. Drug concentrations remained above the inhibitory concentrations for at least six weeks post-operatively. Thus, serial injections of sustained-delivery polymer gel loaded with sirolimus can provide high localized concentrations at target vascular tissues and thus may be useful for the prevention and treatment of vascular proliferative disorders such as hemodialysis graft stenosis. In addition, MRI is useful for the monitoring of the location of the drug depot.
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Affiliation(s)
- Shawn C Owen
- Department of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, 301 Skaggs Hall, 30 South 2000 East, Salt Lake City, UT 84112, USA
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Preston JS, Tasdizen T, Terry CM, Cheung AK, Kirby RM. Using the stochastic collocation method for the uncertainty quantification of drug concentration due to depot shape variability. IEEE Trans Biomed Eng 2009; 56:609-20. [PMID: 19272865 DOI: 10.1109/tbme.2008.2009882] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Numerical simulations entail modeling assumptions that impact outcomes. Therefore, characterizing, in a probabilistic sense, the relationship between the variability of model selection and the variability of outcomes is important. Under certain assumptions, the stochastic collocation method offers a computationally feasible alternative to traditional Monte Carlo approaches for assessing the impact of model and parameter variability. We propose a framework that combines component shape parameterization with the stochastic collocation method to study the effect of drug depot shape variability on the outcome of drug diffusion simulations in a porcine model. We use realistic geometries segmented from MR images and employ level-set techniques to create two alternative univariate shape parameterizations. We demonstrate that once the underlying stochastic process is characterized, quantification of the introduced variability is quite straightforward and provides an important step in the validation and verification process.
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Affiliation(s)
- J Samuel Preston
- Scientific Computing and Imaging Institute and the School of Computing, University of Utah, Salt Lake City, UT 84112, USA.
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Terry CM, Kim SE, Li L, Goodrich KC, Hadley JR, Blumenthal DK, Parker DL, Cheung AK. Longitudinal assessment of hyperplasia using magnetic resonance imaging without contrast in a porcine arteriovenous graft model. Acad Radiol 2009; 16:96-107. [PMID: 19064217 DOI: 10.1016/j.acra.2008.05.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 05/19/2008] [Accepted: 05/19/2008] [Indexed: 12/25/2022]
Abstract
RATIONALE AND OBJECTIVES Chronic hemodialysis requires a vascular access that provides high blood-flow rates for the extracorporeal recirculation of blood. Synthetic arteriovenous (AV) grafts often fail because of clotting caused by underlying hyperplasia formation. The authors report the use of magnetic resonance (MR) imaging (MRI) without contrast agent to monitor tissue hyperplasia formation as well as luminal area in a porcine model of AV graft stenosis. MATERIALS AND METHODS Expanded reinforced polytetrafluoroethylene grafts were surgically placed between the common carotid artery and the external jugular vein, bilaterally, in pigs. Animals underwent MRI in a 3-T scanner at 3, 4, or 6 weeks after graft placement, followed by euthanasia and the collection of grafts and adjacent tissues for histologic analysis. Two animals underwent sequential scanning at 1, 2, 3, 5, and 7 weeks after graft placement, followed by histologic analysis. RESULTS Measurements of hyperplasia obtained from the MR images were compared with, and correlated well with, measurements obtained from the histologic cross-sections (r = 0.932, P = .02). The MR images provided a more complete view of the venous hyperplasia throughout the graft compared with histology. The MR images could be examined from multiple angles and were unaffected by histologic preparation artifacts. CONCLUSION Unlike histology, MRI provided longitudinal 3-dimensional views of hyperplasia within the AV grafts. This ability of MRI to more completely identify the geometry of hyperplasia and to quantify the tissue volume in vivo could provide benefits over histologic analysis in assessing the pathology of AV graft failure and the efficacy of antihyperplasia interventions.
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Affiliation(s)
- Christi M Terry
- Department of Medicine, Division of Nephrology and Hypertension, University of Utah, Salt Lake City, UT 84112, USA.
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Li L, Terry CM, Shiu YTE, Cheung AK. Neointimal hyperplasia associated with synthetic hemodialysis grafts. Kidney Int 2008; 74:1247-61. [PMID: 18668026 DOI: 10.1038/ki.2008.318] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Stenosis is a major cause of failure of hemodialysis vascular grafts and is primarily caused by neointimal hyperplasia (NH) at the anastomoses. The objective of this article is to provide a scientific review of the biology underlying this disorder and a critical review of the state-of-the-art investigational preventive strategies in order to stimulate further research in this exciting area. The histology of the NH shows myofibroblasts (that are probably derived from adventitial fibroblasts), extracellular matrices, pro-inflammatory cells including foreign-body giant cells, a variety of growth factors and cytokines, and neovasculature. The contributing factors of the pathogenesis of NH include surgical trauma, bioincompatibility of the synthetic graft, and the various mechanical stresses that result from luminal hypertension and compliance mismatch between the vessel wall and graft. These mechanical stimuli are focal in nature and may have a significant influence on the preferential localization of the NH. Novel mechanical graft designs and local drug delivery strategies show promise in animal models in preventing graft NH development. Successful prevention of graft stenosis would provide a superior alternative to the native fistula as hemodialysis vascular access.
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Affiliation(s)
- Li Li
- Department of Medicine, University of Utah, Salt Lake City, Utah, USA
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Cheung AK, Terry C, Li L. Pathogenesis and local drug delivery for prevention of vascular access stenosis. J Ren Nutr 2008; 18:140-5. [PMID: 18089461 DOI: 10.1053/j.jrn.2007.10.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
A well-functioning vascular access is essential for hemodialysis in end-stage kidney disease patients. Synthetic grafts are more prone to the development of stenosis than native fistulas. Most of the stenosis is caused by neointimal hyperplasia localized at the outflow tract, which is perpetuated by continuous stimuli, such as blood flow disturbance, graft material bioincompatibility, and repeated needle puncture. Hyperplasia formation is also enhanced by the trauma of angioplasty. Recent work suggests that angiogenesis and the migration and proliferation of fibroblasts in the adventitia are important for the pathogenesis of neointimal hyperplasia. Therefore, the perivascular sustained delivery of antiproliferative drugs is a rational approach to inhibit hyperplasia associated with hemodialysis grafts. Because of the chronic nature of the stimuli, strategies that allow for the ready replenishment of the drug depot are preferable and are currently under development.
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Affiliation(s)
- Alfred K Cheung
- Veterans Affair Salt Lake City Healthcare System, Salt Lake City, Utah, USA.
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22
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Dember LM, Dixon BS. Early Fistula Failure: Back to Basics. Am J Kidney Dis 2007; 50:696-9. [DOI: 10.1053/j.ajkd.2007.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 09/19/2007] [Indexed: 11/11/2022]
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Kohler TR, Toleikis PM, Gravett DM, Avelar RL. Inhibition of neointimal hyperplasia in a sheep model of dialysis access failure with the bioabsorbable Vascular Wrap⁎⁎Vascular Wrap is a trademark of Angiotech Pharmaceuticals, Inc. paclitaxel-eluting mesh. J Vasc Surg 2007; 45:1029-1037; discussion 1037-8. [DOI: 10.1016/j.jvs.2007.01.057] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2006] [Accepted: 01/19/2007] [Indexed: 11/28/2022]
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Terry CM, Blumenthal DK, Sikharam S, Li L, Kuji T, Kern SE, Cheung AK. Evaluation of histological techniques for quantifying haemodialysis arteriovenous (AV) graft hyperplasia. Nephrol Dial Transplant 2006; 21:3172-9. [PMID: 16957014 DOI: 10.1093/ndt/gfl366] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Assessing treatment efficacies for preventing haemodialysis arteriovenous (AV) graft stenosis requires a reproducible method for quantifying intimal hyperplasia. We identified sources of variability in three histological methods for assessing hyperplasia in a porcine AV graft model. METHODS Carotid-jugular synthetic grafts were placed in pigs. After explantation at 3-6 weeks, the tissue was stained with haematoxylin and eosin (H&E), Masson's trichrome or elastic tissue Van Gieson (EVG) stains and examined histologically. Hyperplasia at the anastomosis of 14 grafts was quantified using three different methods, each by four blinded observers. These methods were visual scoring, ratio of intima-to-media surface area (I/M ratio), and ratio of intra-graft hyperplasia to graft surface area (H/G ratio) at the graft-vessel interface. RESULTS The EVG stain proved superior in delineation of the elastic lamina yet quantification of the intimal and medial layers was still often difficult. This is illustrated by the greater inter-observer median coefficient of variances (CV) found using the I/M ratio method (intimal area CV=13.7%; medial area CV=32.7%; I/M ratio CV=44.0%) than with the H/G method (intra-graft hyperplasia area CV=7.3%, graft area CV=5.3%; H/G ratio CV=6.9%) or by visual scoring (CV=26.8%). The H/G ratios correlated positively with visual scores (r=0.941; P=0.0007; n=14) and the I/M ratio (r=0.719; P=0.0095; n=14). While hyperplasia was seen in both native vessel and graft lumen, in only one of the 14 anastomoses was the degree of hyperplasia greater in the native vessel than in the graft lumen, suggesting that the degree of hyperplasia occurring within the graft lumen predicted the total hyperplasia around the anastomosis. CONCLUSIONS The H/G method for assessing hyperplasia is preferred in a porcine model of AV graft because it is quantitative, less variable and does not require the delineation of the elastic lamina, although it infrequently underestimates the total hyperplasia that occurs.
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Affiliation(s)
- Christi M Terry
- Department of Medicine, University of Utah and Medical Service, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, UT 84112-5350, USA.
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