Extracellular matrix degrading enzymes are active in porcine stentless aortic bioprosthetic heart valves
Extracellular matrix degrading enzymes are active in porcine stentless aortic bioprosthetic heart valves
复制标题
DOI：
10.1002/jbm.a.10066
复制
发表时间：
2003-09-15
影响因子：
4.9
通讯作者：
Vyavahare, NR
中科院分区：
文献类型：
--
作者：
Simionescu, DT;Lovekamp, JJ;Vyavahare, NR
戊二醛固定的猪主动脉瓣组织广泛用于人工生物心脏瓣膜（BHV）形式的心脏瓣膜置换手术。BHV在临床环境中的耐久性受到组织变性、机械失效和钙化的限制。BHV依赖于戊二醛使生物组织代谢惰性并完全抵抗酶攻击的推定能力。在本研究中，我们检测并部分表征了未植入的戊二醛固定的猪主动脉瓣尖和壁组织中胶原蛋白和弹性蛋白降解酶的活性，并将酶活性与从新鲜组织中提取的酶活性进行比较。发现能够降解细胞外基质的活性酶以可溶形式存在，并且固定在戊二醛交联的组织基质上。对于戊二醛固定的壁和瓣尖组织，胶原溶解活性的总水平被评价为约0.25 μ g降解胶原/mg干组织/24 h。本研究的一个主要发现是可溶性组织酶能够部分降解戊二醛固定的胶原蛋白，特别是大量的戊二醛固定的弹性蛋白。这些钙依赖性明胶酶与基质金属蛋白酶有许多生化相似性。这些数据有力地表明，戊二醛固定的猪瓣膜组织不是代谢惰性的，并且不完全抵抗酶的攻击，从而使BHV容易发生生物变性和随后的慢性衰竭。(C)2003 Wiley Periodicals，Inc.
Glutaraldehyde-fixed porcine aortic valve tissues are widely used for heart valve replacement surgery in the form of bioprosthetic heart valves (BHVs). The durability of BHVs in the clinical setting is limited by tissue degeneration, mechanical failure, and calcification. BHVs rely on the putative ability of glutaraldehyde to render biologic tissues metabolically inert and fully resistant to enzymatic attack. In the present study, we detected and partially characterized the activity of collagen and elastin-degrading enzymes in unimplanted, glutaraldehyde-fixed porcine aortic cusp and wall tissues and compared enzyme activities with those extracted from fresh tissues. Active enzymes capable of degrading extracellular matrix were found to be present in soluble form as well as immobilized on glutaraldehyde-crosslinked tissue matrix. Total levels of collagenolytic activities were evaluated to approximately 0.25 mug of degraded collagen/mg of dry tissue/24 h for both glutaraldehyde-fixed wall and cusp tissues. A major finding of this study was the ability of soluble tissue enzymes to partially degrade glutaraldehyde-fixed collagen and particularly large amounts of glutaraldehyde-fixed elastin. These calcium-dependent gelatinases share many biochemical similarities with matrix metalloproteinases. These data strongly indicate that glutaraldehyde-fixed porcine valvular tissues are not metabolically inert and are not entirely resistant to enzymatic attack, thereby rendering BHVs vulnerable to biologic degeneration and subsequent chronic failure. (C) 2003 Wiley Periodicals, Inc.