Ozawa Tsukasa, Mickle Donald A G, Weisel Richard D, Koyama Nobuya, Ozawa Sumiko, Li Ren-Ke
Department of Surgery, Division of Cardiovascular Surgery, Toronto General Research Institute, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada.
Circulation. 2002 Sep 24;106(12 Suppl 1):I176-82.
The optimal cardiac graft for the repair of congenital heart defects will be composed of autologous cells and will grow with the child. The biodegradable material should permit rapid cellular growth and delayed degradation with minimal inflammation. We compared a new material, epsilon-caprolactone-co-L-lactide sponge reinforced with knitted poly-L-lactide fabric (PCLA), to gelatin (GEL) and polyglycolic acid (PGA), which are previously evaluated materials.
Syngenic rat aortic smooth muscle cells (SMCs, 2x10(6)) were seeded onto GEL, PGA, and PCLA patches and cultured (n=11 per group). The DNA content in each patch was measured at 1, 2, and 3 weeks after seeding. Histological examination was performed 2 weeks after seeding. Cell-seeded patches were employed to replace a surgically created defect in the right ventricular outflow tract (RVOT) of rats (n=5 per group). Histology was studied at 8 weeks following implantation.
In vitro studies showed that the DNA content increased significantly (P<0.05) in all patches between 1 and 3 weeks after seeding. Histology and staining SMCs for anti-alpha-smooth muscle actin (alphaSMA) revealed better growth of cells in the interstices of the grafts with GEL and PCLA than the PGA graft. In vivo studies demonstrated that seeded SMCs survived at least 8 weeks after the patch implantation in all groups. PCLA scaffolds were replaced by more cells with larger alphaSMA-positive areas and by more extracellular matrix with larger elastin-positive areas than with GEL and PGA. The patch did not thin and expanded significantly. The GEL and PGA patches thinned and expanded. All grafts had complete endothelialization on the endocardial surface.
SMC-seeded biodegradable materials can be employed to repair the RVOT. The novel PCLA patches permitted better cellular penetration in vitro and did not thin or dilate in vivo and did not produce an inflammatory response. The cell-seeded PCLA patch may permit the construction of an autologous patch to repair congenital heart defects.
用于修复先天性心脏缺陷的理想心脏移植物应由自体细胞构成，并能随患儿生长。可生物降解材料应能促进细胞快速生长，延缓降解，且炎症反应最小。我们将一种新型材料，即由针织聚-L-丙交酯织物增强的ε-己内酯-共-L-丙交酯海绵（PCLA），与明胶（GEL）和聚乙醇酸（PGA）进行了比较，后者是先前已评估过的材料。
将同基因大鼠主动脉平滑肌细胞（SMCs，2×10⁶）接种到GEL、PGA和PCLA补片上并进行培养（每组n = 11）。接种后1、2和3周测量各补片中的DNA含量。接种后2周进行组织学检查。将接种细胞的补片用于替换大鼠右心室流出道（RVOT）手术造成的缺损（每组n = 5）。植入后8周进行组织学研究。
体外研究显示，接种后1至3周，所有补片中的DNA含量均显著增加（P<0.05）。组织学检查以及用抗α-平滑肌肌动蛋白（αSMA）对SMCs进行染色显示，与PGA补片相比，GEL和PCLA补片缝隙中的细胞生长更好。体内研究表明，接种的SMCs在所有组的补片植入后至少存活8周。与GEL和PGA相比，PCLA支架被更多具有更大αSMA阳性区域的细胞以及更多具有更大弹性蛋白阳性区域的细胞外基质所替代。补片未明显变薄和扩张。GEL和PGA补片变薄且扩张。所有移植物的心内膜表面均实现了完全内皮化。
接种SMCs的可生物降解材料可用于修复RVOT。新型PCLA补片在体外允许更好的细胞渗透，在体内未变薄或扩张，也未产生炎症反应。接种细胞的PCLA补片可能有助于构建自体补片以修复先天性心脏缺陷。
