Sun Wendell Q, Gouk Sok-Siam
LifeCell Corporation , One Millennium Way, Branchburg, New Jersey 08876, USA.
Tissue Eng Part C Methods. 2009 Mar;15(1):23-31. doi: 10.1089/ten.tec.2008.0164.
Tissue products will age upon storage. Although a number of tissue products have been used for tissue repair and regeneration for more than a decade, no study has been published on the aging of tissue products and its potential effect on product function. This study investigated aging-caused changes in a regenerative biologic scaffold (AlloDerm native tissue matrix) upon storage at accelerated conditions. Tissue matrix was stored at elevated humidity (33%, 75%, and 85% relative humidity [RH]) and temperature (40 +/- 2 degrees C). The study measured the accumulation of advanced glycation end-products (Maillard products), and the changes of tissue structure, tissue stability, and mechanical properties as well as in vitro fibroblast repopulation. Tissue products stored at 75% RH and 85% RH changed significantly, including collagen condensation and cross-linking, increased breaking strength, and decreased elasticity. The aged products became less stable, as demonstrated by lower denaturation temperature, lower denaturation enthalpy, and higher susceptibility to nonspecific proteolytic action. In comparison, changes were nondetectable in control products stored at 2 degrees C to 8 degrees C, or very small in tissue products stored at 33% RH and 40 degrees C. Changes of tissue structure and stability were correlated highly with the formation of Maillard products, suggesting a role of Maillard reactions in tissue aging during storage. Calorimetric analysis revealed that tissue products stored at 2 degrees C to 8 degrees C and at 33% RH and 40 degrees C were in the glassy state, whereas the products stored at 75% RH, 85% RH, and 40 degrees C were not in the glassy state, suggesting a role of the glassy state in preserving tissue products during storage. Aging did not affect in vitro fibroblast proliferation on tissue matrix, and further tests are needed to investigate how aging may affect in vivo performance of the tissue product.
组织产品在储存过程中会老化。尽管许多组织产品已用于组织修复和再生超过十年，但尚未有关于组织产品老化及其对产品功能潜在影响的研究发表。本研究调查了在加速条件下储存时，再生生物支架（AlloDerm天然组织基质）因老化引起的变化。组织基质在高湿度（33%、75%和85%相对湿度[RH]）和温度（40±2℃）下储存。该研究测量了晚期糖基化终产物（美拉德产物）的积累，以及组织结构、组织稳定性、机械性能的变化以及体外成纤维细胞的再填充情况。在75%RH和85%RH下储存的组织产品发生了显著变化，包括胶原蛋白浓缩和交联、断裂强度增加以及弹性降低。老化后的产品变得不太稳定，表现为变性温度降低、变性焓降低以及对非特异性蛋白水解作用的敏感性增加。相比之下，在2℃至8℃储存的对照产品中未检测到变化，或在33%RH和40℃储存的组织产品中变化非常小。组织结构和稳定性的变化与美拉德产物的形成高度相关，表明美拉德反应在储存期间组织老化中起作用。量热分析表明，在2℃至8℃以及33%RH和40℃下储存的组织产品处于玻璃态，而在75%RH、85%RH和40℃下储存的产品不处于玻璃态，表明玻璃态在储存期间保存组织产品中起作用。老化不影响组织基质上的体外成纤维细胞增殖，需要进一步测试来研究老化如何影响组织产品的体内性能。
