van den Heever J J, Neethling W M L, Smit F E, Litthauer D, Joubert G
Department of Cardiothoracic Surgery, School of Medicine, University of the Free State, Bloemfontein, 9301, South Africa.
Cell Tissue Bank. 2013 Mar;14(1):53-63. doi: 10.1007/s10561-012-9299-z. Epub 2012 Mar 2.
Porcine heart valves and bovine pericardium exhibit suitable properties for use as substitutes in cardiothoracic surgery, but must meet several requirements to be safe and efficient. Treatment with glutaraldehyde (GA) render some of these requirements, but calcification and degradation post-implant remain a problem. This study aimed to identify additional biochemical treatments that will minimize calcification potential without compromising the physical properties of pericardium. Pericardium treated with GA calcified severely after 8 weeks in the subcutaneous rat model, compared to tissue treated with higher concentrations of glycosaminoglycans (GAG) and commercial Glycar patches. GA, lower concentrations GAG and Glycar pericardium had high denaturation temperatures due to enhanced cross-linking. Tensile strength of GA tissue was significantly lower than GAG-treated or Glycar tissues, due to lower water content with resultant lower flexibility and suppleness. Pericardium treated with 0.01 M GAG gave acceptable denaturation temperatures, tensile strength and reduced calcification potential. All tissue treatments evoked comparable host immune responses, and no significant difference in resistance to enzymatic degradation. Ineffective stabilization and fixation of cross-links following GAG treatment, as well as limited penetration into the pericardium, resulted in GAG leaching out into the surrounding host tissue or storage medium, and prohibits safe clinical use of such tissue.
猪心脏瓣膜和牛心包展现出适合用于心胸外科手术替代物的特性，但必须满足若干要求才能安全且高效。用戊二醛（GA）处理能满足其中一些要求，但植入后钙化和降解仍是个问题。本研究旨在确定额外的生化处理方法，以在不损害心包物理特性的情况下将钙化可能性降至最低。与用高浓度糖胺聚糖（GAG）和商用Glycar贴片处理的组织相比，在皮下大鼠模型中，用GA处理的心包在8周后严重钙化。GA、较低浓度GAG和Glycar心包由于交联增强而具有较高的变性温度。GA处理的组织的拉伸强度显著低于GAG处理或Glycar处理的组织，这是因为含水量较低，导致柔韧性和柔软度降低。用0.01 M GAG处理的心包具有可接受的变性温度、拉伸强度且钙化可能性降低。所有组织处理引发的宿主免疫反应相当，对酶降解的抵抗力无显著差异。GAG处理后交联的稳定和固定无效，以及向心包内的渗透有限，导致GAG渗漏到周围宿主组织或储存介质中，从而禁止这种组织的安全临床应用。
