Kasyanov Vladimir, Isenburg Jason, Draughn Robert A, Hazard Starr, Hodde Jason, Ozolanta Iveta, Murovska Modra, Halkes S Bart, Vrasidas Ioannis, Liskamp Rob M J, Pieters Roland J, Simionescu Dan, Markwald Roger R, Mironov Vladimir
Medical University of South Carolina, Charleston, SC 29425, USA.
Biomaterials. 2006 Feb;27(5):745-51. doi: 10.1016/j.biomaterials.2005.06.022. Epub 2005 Aug 18.
Chemical stabilization resulting in increased resistance to proteolytic degradation is one of the approaches in prevention of post-implantational aneurysm development in decellularized natural vascular scaffolds. Recently, tannic acid (TA) and tannic acid mimicking dendrimers (TAMD) have been suggested as potential stabilization agents for collagen and elastin. The aim of this work was to determine the stabilizing effects of TAMD on decellularized natural scaffolds. Vascular scaffolds fabricated from small intestine submucosa (SIS) and SIS plane sheets (Cook Biotech Inc.) were used. The biomechanical properties of the SIS vascular graft segments treated with TA and TAMD were tested. The effect of TAMD treatment on resistance to proteolytic degradation was evaluated by measuring biomechanical properties of TAMD stabilized and non-stabilized SIS specimens after incubation in collagenase solution. It was shown that treatment with TA as well as with TAMD increased the strength of tubular SIS as well as their resistance to proteolytic biodegradation manifested by preservation of biomechanical properties after collagenase treatment. Transmission electron microscopy demonstrated that treatment with TAMD increased the periodical pattern typical of collagen fiber ultrastructure as a result of the "mordant" effect. The possible collagen cross-linking effect of TAMD on SIS was investigated by differential scanning calorimetry (DSC). The treatment with TAMD induced a small, but detectable cross-linking effect, suggesting that TAMD do not establish extensive covalent cross links within the extracellular matrix but rather interact with collagen, thus rendering SIS scaffolds more resistant to proteolytic degradation.
化学稳定化导致对蛋白水解降解的抗性增加是预防脱细胞天然血管支架植入后动脉瘤形成的方法之一。最近，单宁酸（TA）和模仿单宁酸的树枝状聚合物（TAMD）已被提议作为胶原蛋白和弹性蛋白的潜在稳定剂。这项工作的目的是确定TAMD对脱细胞天然支架的稳定作用。使用从小肠黏膜下层（SIS）和SIS平板（Cook Biotech Inc.）制备的血管支架。测试了用TA和TAMD处理的SIS血管移植物段的生物力学性能。通过测量在胶原酶溶液中孵育后TAMD稳定化和未稳定化的SIS标本的生物力学性能，评估TAMD处理对蛋白水解降解抗性的影响。结果表明，用TA以及TAMD处理可提高管状SIS的强度及其对蛋白水解生物降解的抗性，这表现为胶原酶处理后生物力学性能的保留。透射电子显微镜表明，由于“媒染”作用，用TAMD处理增加了胶原纤维超微结构典型的周期性模式。通过差示扫描量热法（DSC）研究了TAMD对SIS可能的胶原交联作用。用TAMD处理诱导了一个小的但可检测到的交联作用，这表明TAMD在细胞外基质内不会形成广泛的共价交联，而是与胶原蛋白相互作用，从而使SIS支架对蛋白水解降解更具抗性。
