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Lee C, Park CS, Lee CH, Kwak JG, Kim SJ, Shim WS, Song JY, Choi EY, Lee SY. Durability of bioprosthetic valves in the pulmonary position: Long-term follow-up of 181 implants in patients with congenital heart disease. J Thorac Cardiovasc Surg 2011; 142:351-8. [DOI: 10.1016/j.jtcvs.2010.12.020] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 10/29/2010] [Accepted: 12/16/2010] [Indexed: 11/29/2022]
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152
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Wong ML, Leach JK, Athanasiou KA, Griffiths LG. The role of protein solubilization in antigen removal from xenogeneic tissue for heart valve tissue engineering. Biomaterials 2011; 32:8129-38. [PMID: 21810537 DOI: 10.1016/j.biomaterials.2011.07.030] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 07/11/2011] [Indexed: 11/19/2022]
Abstract
Decellularization techniques have been developed in an attempt to reduce the antigenicity of xenogeneic biomaterials, a critical barrier in their use as tissue engineering scaffolds. However, numerous studies have demonstrated inadequate removal and subsequent persistence of antigens in the biomaterial following decellularization, resulting in an immune response upon implantation. Thus, methods to enhance antigen removal (AR) are critical for the use of xenogeneic biomaterials in tissue engineering and regenerative medicine. In the present study, AR methods incorporating protein solubilization principles were investigated for their ability to reduce antigenicity of bovine pericardium (BP) for heart valve tissue engineering. Bovine pericardium following AR (BP-AR) was assessed for residual antigenicity, tensile properties, and extracellular matrix composition. Increasing protein solubility during AR significantly decreased the residual antigenicity of BP-AR-by an additional 80% compared to hypotonic solution or 60% compared to 0.1% (w/v) SDS decellularization methods. Moreover, solubilizing agents have a dominant effect on reducing the level of residual antigenicity of BP-AR beyond that achieved by AR additives alone. Tested AR methods did not compromise the tensile properties of BP-AR compared to native BP. Furthermore, residual cell nuclei did not correlate to residual antigenicity, demonstrating that residual nuclei counts may not be an appropriate indicator of successful AR. In conclusion, AR strategies promoting protein solubilization significantly reduced residual antigens compared to decellularization methods without compromising biomaterial functional properties. This study demonstrates the importance of solubilizing protein antigens for their removal in the generation of xenogeneic scaffolds.
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Affiliation(s)
- Maelene L Wong
- Department of Biomedical Engineering, University of California, Davis, Davis, CA 95616, USA
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153
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McGregor CG, Carpentier A, Lila N, Logan JS, Byrne GW. Reply to the Editor. J Thorac Cardiovasc Surg 2011. [DOI: 10.1016/j.jtcvs.2011.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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154
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Manji RA, Menkis AH, Cooper DKC. Cardiac xenotransplantation technology provides materials for improved bioprosthetic heart valves. J Thorac Cardiovasc Surg 2011; 142:238-9; author reply 239. [PMID: 21683844 DOI: 10.1016/j.jtcvs.2011.02.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 02/11/2011] [Indexed: 11/19/2022]
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155
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Lim HG, Kim SH, Choi SY, Kim YJ. Anticalcification effects of decellularization, solvent, and detoxification treatment for genipin and glutaraldehyde fixation of bovine pericardium. Eur J Cardiothorac Surg 2011; 41:383-90. [DOI: 10.1016/j.ejcts.2011.05.016] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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156
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Fournier PE, Thuny F, Grisoli D, Lepidi H, Vitte J, Casalta JP, Weiller PJ, Habib G, Raoult D. A deadly aversion to pork. Lancet 2011; 377:1542. [PMID: 21531269 DOI: 10.1016/s0140-6736(11)60021-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Pierre-Edouard Fournier
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Faculté de Médecine, Université de la Méditerranée, Marseille, France
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McGregor CGA, Carpentier A, Lila N, Logan JS, Byrne GW. Cardiac xenotransplantation technology provides materials for improved bioprosthetic heart valves. J Thorac Cardiovasc Surg 2011; 141:269-75. [PMID: 21168032 DOI: 10.1016/j.jtcvs.2010.08.064] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 08/11/2010] [Accepted: 08/23/2010] [Indexed: 10/18/2022]
Abstract
OBJECTIVES Human subjects and Old World primates have high levels of antibody to galactose-α-1,3 galactose β-1,4-N-acetylglucosamine (α-Gal). Commercially available bioprosthetic heart valves of porcine and bovine origin retain the Gal antigen despite current processing techniques. Gal-deficient pigs eliminate this xenoantigen. This study tests whether binding of human anti-Gal antibody effects calcification of wild-type and Gal-deficient glutaraldehyde-fixed porcine pericardium by using a standard subcutaneous implant model. METHODS Expression of α-Gal was characterized by lectin Griffonia simplicifolia-IB4 staining. Glutaraldehyde-fixed pericardial disks from Gal-positive and Gal-deficient pigs were implanted into 12-day-old Wistar rats and 1.5-kg rabbits with and without prelabeling with affinity-purified human anti-Gal antibody. Calcification of the implants was determined after 3 weeks by using inductively coupled plasma spectroscopy. RESULTS The α-Gal antigen was detected in wild-type but not Gal-deficient porcine pericardium. Wild-type disks prelabeled with human anti-Gal antibody exhibited significantly greater calcification compared with that seen in antibody-free wild-type samples (mean ± standard error of the mean: 111 ± 8.4 and 74 ± 9.6 mg/g, respectively; P = .01). In the presence of anti-Gal antibody, a significantly greater level of calcification was detected in wild-type compared with GTKO porcine pericardium (111 ± 8.4 and 55 ± 11.8 mg/g, respectively; P = .005). Calcification of Gal-deficient pericardium was not affected by the presence of anti-Gal antibody (51 ± 9.1 and 55 ± 11.8 mg/g). CONCLUSIONS In this model anti-Gal antibody accelerates calcification of wild-type but not Gal-deficient glutaraldehyde-fixed pericardium. This study suggests that preformed anti-Gal antibody present in all patients might contribute to calcification of currently used bioprosthetic heart valves. Gal-deficient pigs might become the preferred source for new, potentially calcium-resistant bioprosthetic heart valves.
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158
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Questionable model choice in valve calcification research addressing α-Gal. J Heart Lung Transplant 2010; 29:911-2; discussion 912-3. [DOI: 10.1016/j.healun.2010.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Accepted: 03/18/2010] [Indexed: 11/19/2022] Open
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159
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Hwang SW, Kim YJ, Kim SH, Choi SH. Anti-calcification Effects in Decellularized and Variously Fixed Bovine Pericardium. THE KOREAN JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY 2010. [DOI: 10.5090/kjtcs.2010.43.3.235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Seong Wook Hwang
- Department of Thoracic and Cardiovascular Surgery, Seoul Natinal Universtiy Bundang Hospital
| | - Yong-Jin Kim
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital
| | - Soo Hwan Kim
- Seoul National University Hospital Clinical Research Institute, Xenotransplantation Research Center
| | - Seung-Hwa Choi
- Seoul National University Hospital Clinical Research Institute, Xenotransplantation Research Center
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160
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Lai E, Schwartz JI, Dallob A, Jumes P, Liu F, Kraft WK, Royalty J, Chodakewitz JA, Mccrary Sisk C, Radziszewski W, Wagner JA. Effects of extended release niacin/laropiprant, laropiprant, extended release niacin and placebo on platelet aggregation and bleeding time in healthy subjects. Platelets 2010; 21:191-8. [DOI: 10.3109/09537100903521611] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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161
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Wiedemann D, Bonaros N, Laufer G, Kocher A. Aortic Bioprosthetic Valve Deterioration 8 Months After Implantation. Ann Thorac Surg 2010; 89:277-9. [DOI: 10.1016/j.athoracsur.2009.06.081] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2009] [Revised: 06/10/2009] [Accepted: 06/15/2009] [Indexed: 10/20/2022]
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162
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163
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Mathieu P, Després JP, Pibarot P. The 'valvulo-metabolic' risk in calcific aortic valve disease. Can J Cardiol 2009; 23 Suppl B:32B-39B. [PMID: 17932585 DOI: 10.1016/s0828-282x(07)71008-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Calcific aortic stenosis (AS) has been considered a degenerative and unmodifiable process resulting from aging and 'wear and tear' of the aortic valve. Over the past decade, studies in the field of epidemiology, molecular biology and lipid metabolism have highlighted similarities between vascular atherosclerosis and calcific AS. In particular, work from the Quebec Heart Institute and from that of others has documented evidence of valvular infiltration by oxidized low-density lipoproteins and the presence of inflammatory cells, along with important tissue remodelling in valves explanted from patients with AS. Recent studies have also emphasized the role of visceral obesity in the development and progression of AS. In addition, visceral obesity, with its attendant metabolic complications, commonly referred to as the metabolic syndrome, has been associated with degenerative changes in bioprosthetic heart valves. The purpose of the present review is to introduce the concept of 'valvulo-metabolic risk' and to provide an update on the recent and important discoveries regarding the pathogenesis of heart valve diseases in relation to obesity, and to discuss how these novel mechanisms might translate into clinical practice.
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Affiliation(s)
- Patrick Mathieu
- Laboratoire d'Etudes Moléculaires des Valvulopathies, Groupe de Recherche en Valvulopathies, Laval Hospital Research Center/Quebec Heart Institute, Department of Surgery, Québec, Quebec.
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164
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Shetty R, Pibarot P, Audet A, Janvier R, Dagenais F, Perron J, Couture C, Voisine P, Després JP, Mathieu P. Lipid-mediated inflammation and degeneration of bioprosthetic heart valves. Eur J Clin Invest 2009; 39:471-80. [PMID: 19490057 DOI: 10.1111/j.1365-2362.2009.02132.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND The durability of bioprosthetic valves is limited by structural valve degeneration (SVD) leading to bioprostheses (BPs) stenosis or regurgitation. We hypothesized that a lipid-mediated inflammatory mechanism is involved in the SVD of BPs. MATERIAL AND METHODS Eighteen Freestyle stentless BP valves were explanted for SVD at a mean time of 5.9 +/- 3 years after implantation and were analysed by immunohistochemistry and transmission electron microscopy (TEM). RESULTS The mean age of the patients was 65 +/- 8 years and there were 11 male and seven female patients. Two of the 18 BPs had macroscopic calcification, whereas the other valves had minimal or no macroscopic calcification. Tears at the commissures leading to regurgitation was present in 16 BPs. Immunohistochemistry showed the presence of oxidized low-density lipoprotein (ox-LDL) and glycosaminoglycans in the fibrosa layer of 13 BPs. Areas with ox-LDL were infiltrated by macrophages (CD68(+)) co-expressing the scavenger receptor CD36 and metalloproteinase-9 (MMP-9). Zymogram showed the active form of MMP-9 within explanted BPs. EM studies revealed the presence of lipid-laden cells featuring foam cells and fragmented collagen. Nonimplanted control BPs obtained from the manufacturer (n = 4) had no evidence of lipid accumulation, inflammatory cell infiltration or expression of MMP9 within the leaflets. CONCLUSIONS These results support the concept that lipid-mediated inflammatory mechanisms may contribute to the SVD of BPs. These findings suggest that modification of atherosclerotic risk factors with the use of behavioural or pharmacological interventions could help to reduce the incidence of SVD.
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Affiliation(s)
- R Shetty
- Laval University, Quebec, QC, Canada
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165
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Griffiths LG, Choe L, Lee KH, Reardon KF, Orton EC. Protein extraction and 2-DE of water- and lipid-soluble proteins from bovine pericardium, a low-cellularity tissue. Electrophoresis 2009; 29:4508-15. [PMID: 18985661 DOI: 10.1002/elps.200800108] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bovine pericardium (BP) is an important biomaterial used in the production of glutaraldehyde-fixed heart valves and tissue-engineering applications. The ability to perform proteomic analysis on BP is useful for a range of studies, including investigation of immune rejection after implantation. However, proteomic analysis of fibrous tissues such as BP is challenging due to their relative low-cellularity and abundance of extracellular matrix. A variety of methods for tissue treatment, protein extraction, and fractionation were investigated with the aim of producing high-quality 2-DE gels for both water- and lipid-soluble BP proteins. Extraction of water-soluble proteins with 3-(benzyldimethylammonio)-propanesulfonate followed by n-dodecyl beta-D-maltoside extraction and ethanol precipitation for lipid-soluble proteins provided the best combination of yield, spot number, and resolution on 2-DE gels (Protocol E2). ESI-quadrupole/ion trap or MALDI-TOF/TOF MS protein identifications were performed to confirm bovine origin and appropriate subcellular prefractionation of resolved proteins. Twenty-five unique, predominantly cytoplasmic bovine proteins were identified from the water-soluble fraction. Thirty-two unique, predominantly membrane bovine proteins were identified from the lipid-soluble fraction. These results demonstrated that the final protocol produced high-quality proteomic data from this important tissue for both cytoplasmic and membrane proteins.
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Affiliation(s)
- Leigh G Griffiths
- Department of Clinical Sciences, Colorado State University, Fort Collins, CO, USA.
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166
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Pibarot P, Dumesnil JG. Prosthetic heart valves: selection of the optimal prosthesis and long-term management. Circulation 2009; 119:1034-48. [PMID: 19237674 DOI: 10.1161/circulationaha.108.778886] [Citation(s) in RCA: 434] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Philippe Pibarot
- Department of Medicine, Laval Hospital Research Center/Québec Heart Institute, Laval University, 2725 Chemin Sainte-Foy, Québec, Canada.
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167
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Kerdjoudj H, Berthelemy N, Rinckenbach S, Kearney-Schwartz A, Montagne K, Schaaf P, Lacolley P, Stoltz JF, Voegel JC, Menu P. Small vessel replacement by human umbilical arteries with polyelectrolyte film-treated arteries: in vivo behavior. J Am Coll Cardiol 2008; 52:1589-97. [PMID: 19007598 DOI: 10.1016/j.jacc.2008.08.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Revised: 07/30/2008] [Accepted: 08/04/2008] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate the patency of human umbilical arteries treated with polyelectrolyte multilayers (PEMs) after rabbit implantation. BACKGROUND The development of small-caliber vascular substitutes with high patency after implantation remains a real challenge for vascular tissue engineering. METHODS Cryopreserved human umbilical arteries were enzymatically de-endothelialized and the luminal surfaces were coated with poly(styrene sulfonate)/poly(allylamine hydrochloride) (PSS/PAH) multilayers. The PEM-untreated arteries and PEM-treated rabbit carotids were used as graft control. The native rabbit carotids were bypassed by grafts. RESULTS The Doppler ultrasound evaluation, performed in vivo, showed that all PEM-treated grafts remained patent during the full experimental period, whereas after only 1 week, no blood circulation was detected in untreated arteries. Scanning electron microscopy and histological graft examination showed pervasive thrombus formation on the luminal surface of untreated arteries after 1 week and clean luminal surface for treated arteries for at least up to 12 weeks. The arterial wall cells were identified through alpha-smooth muscle actin alphaupsilondelta platelet endothelial cell adhesion molecule-1 expression. The smooth muscle cells positive to alpha-smooth muscle actin were identified in adventitia and media and the endothelial cells positive to platelet endothelial cell adhesion molecule in intima. Von Kossa reaction didn't reveal any calcium salt deposits on the wall arteries, suggesting a good wall remodelling with no sign of graft rejection. CONCLUSIONS The in vivo evaluation of human umbilical arteries treated with PSS/PAH multilayers demonstrated a high graft patency after 3 months of implantation. Such modified arteries could constitute a useful option for small vascular replacement.
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Affiliation(s)
- Halima Kerdjoudj
- Group of Bioengineering, LEMTA-UMR CNRS 7563, School of Medicine, Nancy University, Vandoeuvre-lès-Nancy, France
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168
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Mathieu P. Abdominal obesity and the metabolic syndrome: a surgeon's perspective. Can J Cardiol 2008; 24 Suppl D:19D-23D. [PMID: 18787732 DOI: 10.1016/s0828-282x(08)71045-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Over the past decade, a major shift in the clinical risk factors in the population undergoing a cardiac surgery has been observed. In the general population, an increasing prevalence of obesity has largely contributed to the development of cardiovascular disorders. Obesity is a heterogeneous condition in which body fat distribution largely determines metabolic perturbations. Consequently, individuals characterized by increased abdominal fat deposition and the so-called metabolic syndrome (MetS) have a higher risk of developing coronary artery disease. Recent studies have also emphasized that visceral obesity is a strong risk factor for the development of heart valve diseases. In fact, individuals characterized by visceral obesity and its metabolic consequences, such as the small dense low-density lipoprotein phenotype, have a faster progression rate of aortic stenosis, which is related to increased valvular inflammation. Furthermore, the degenerative process of implanted bioprostheses is increased in subjects with the MetS and/or diabetes, suggesting that a process akin to atherosclerosis could be involved in the failure of bioprostheses. In addition to being an important risk factor for the development of cardiovascular disorders, the MetS is increasing the operative mortality risk following coronary artery bypass graft surgery. Thus, recent evidence supports visceral obesity as a global risk factor that is affecting the development of many heart disorders, and that is also impacting negatively on the results of patients undergoing surgical treatment for cardiovascular diseases. In the present paper, recent concepts surrounding the MetS and its implications in various cardiovascular disorders are reviewed along with the clinical implications.
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Affiliation(s)
- Patrick Mathieu
- Laval Hospital, Department of Surgery, Laval University, Sainte-Foy, Quebec.
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169
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Mitigated calcification of glutaraldehyde-fixed bovine pericardium by tannic acid in rats. Chin Med J (Engl) 2008. [DOI: 10.1097/00029330-200809010-00017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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170
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Griffiths LG, Choe LH, Reardon KF, Dow SW, Christopher Orton E. Immunoproteomic identification of bovine pericardium xenoantigens. Biomaterials 2008; 29:3514-20. [PMID: 18514307 DOI: 10.1016/j.biomaterials.2008.05.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Accepted: 05/11/2008] [Indexed: 01/09/2023]
Abstract
Bovine pericardium is an important biomaterial with current application in glutaraldehyde-fixed bioprosthetic heart valves and possible future application as an unfixed biological scaffold for tissue engineering. The importance of both humoral and cell-mediated rejection responses toward fixed and unfixed xenogeneic tissues has become increasingly apparent. However, the full scope and specific identities of bovine pericardium proteins that can elicit an immune response remain largely unknown. In this study, an immunoproteomic approach was used to survey bovine pericardium proteins for their ability to elicit a humoral immune response in rabbits. A two-stage protein extraction protocol was used to separate bovine pericardium proteins into water- and lipid-soluble fractions. Two-dimensional (2-D) gel electrophoresis was performed to separate the proteins from each fraction. Western blots were generated from 2-D gels of both bovine pericardium protein fractions. These blots were probed with serum from rabbits immunized with bovine pericardium and a secondary antibody was used to assess for IgG positivity. Western blots were compared to duplicate 2-D gels and proteins in matched spots were identified by tandem mass spectrometry. Thirty-one putative protein antigens were identified, eight of which are known to be antigenic from previous studies. All of the putative antigens demonstrated progressive staining intensity with increasing days of post-exposure serum. Identified antigenic proteins represented a variety of functional and structural protein types, and included both cellular and matrix proteins. The results of this study have implications for the use of bovine pericardium as a biomaterial in bioprostheses and tissue engineering applications, as well as xenotransplantation in general.
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Affiliation(s)
- Leigh G Griffiths
- Department of Clinical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
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171
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Lehr EJ, Hermary S, McKay RT, Webb DNH, Abazari A, McGann LE, Coe JY, Korbutt GS, Ross DB. NMR Assessment of Me2SO in Decellularized Cryopreserved Aortic Valve Conduits. J Surg Res 2007; 141:60-7. [PMID: 17512545 DOI: 10.1016/j.jss.2007.03.082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 03/13/2007] [Accepted: 03/22/2007] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Decellularized cryopreserved allograft vascular tissue may provide a nonimmunogenic scaffold that is suitable for repopulation by cells from a variety of sources, conferring the potential for growth and repair. Although dimethyl sulfoxide (Me(2)SO) is generally regarded as a safe cryoprotectant, even low levels may alter function of repopulating cells. We investigated the residual concentration of Me(2)SO in the aqueous compartment of cryopreserved ovine aortic valve conduits following decellularization. MATERIALS AND METHODS Aortic valve conduits from Suffolk sheep were cryopreserved in 1.1 M (7.5% vol/vol) Me(2)SO according to the protocol of our local tissue bank. Three aortic valve conduits were decellularized in a series of hypotonic and hypertonic Tris buffers. Tissue samples were taken at regular time intervals throughout the decellularization process and equilibrated in double distilled, deionized H(2)O for 28 days. Quantitative proton nuclear magnetic resonance spectroscopy was used to determine the residual Me(2)SO concentration in the equilibration solutions from which Me(2)SO tissue concentrations were calculated. RESULTS After thawing, the mean Me(2)SO concentration in the valve conduit was 0.302 +/- 0.081 M. The decellularization process resulted in a stepwise reduction in the Me(2)SO concentration to less than 8.56 x 10(-5) +/- 9 x 10(-5) M (P = 0.02). The diffusion coefficient was 2.5 x 10(-6) cm(2)/s. CONCLUSIONS Our study demonstrates that Me(2)SO is effectively washed out of the aortic valve conduit during decellularization, resulting in a final concentration that is several orders of magnitude less than Me(2)SO concentrations reported to alter cell function.
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Affiliation(s)
- Eric J Lehr
- Department of Surgery, University of Alberta, Edmonton, Alberta, Canada.
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172
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