Development of a new bioengineered patch for promoting in situ cellularization and the regeneration of autologous tissue in cardiovascular surgery

自体细胞种植的生物可降解材料作为潜在的心血管移植物引起了广泛的兴趣。但是，这些材料的预处理需要复杂和侵入性的程序，有感染的风险。为了解决这些问题，我们试图开发一种可生物降解的移植材料，含有胶原微海绵，将允许自体血管组织的再生。将聚乳酸-羟基乙酸共聚物（PLA）作为生物可降解支架材料，与胶原微海绵复合，制备成血管补片材料。这些聚（乳酸-羟基乙酸）-胶原补片（有或没有自体血管细胞化）用于修补犬肺动脉干。植入后2个月和6个月进行组织学和生化评估，两组均无血栓形成，两组聚乳酸-羟基乙酸共聚物支架几乎完全吸收。组织学结果显示形成了内皮细胞单层，平滑肌细胞平行排列，血管壁由弹性蛋白和胶原纤维重建。6个月时，补片中的细胞和细胞外成分增加到与天然组织相似的水平。具有和不具有预细胞化的聚（乳酸-羟基乙酸）-胶原微海绵补片显示出良好的组织学结果和耐久性。这种补片显示出作为生物工程材料的前景，用于加速心血管手术中的原位细胞化和自体组织再生。

Biodegradable materials with autologous cell seeding have attracted much interest as potential cardiovascular graft. But, pretreatment of these materials requires a complicated and invasive procedure that carries the risk of infection. To resolve these problems we sought to develop a biodegradable graft material containing collagen microsponge that would permit the regeneration of autologous vessel tissue. The ability of this material to promote in situ cellularization with autologous endothelial an smooth muscle cells was tested with and without precellularization.Poly(lactic-co-glycolic acid) as a biodegradable scaffold was compounded with collagen microsponge to form a vascular patch material. These poly(lactic-co-glycolic acid)-collagen patches with or without autologous vessel cellularization were used to patch the canine pulmonary artery trunk. Histologic and biochemical assessment were performed 2 and 6 months after the implantation.There was no thrombus formation in either group, and the poly(lactic-co-glycolic acid) scaffold was almost completely absorbed in both groups. Histologic results showed the formation of an endothelial cell monolayer, a parallel alignment of smooth muscle cells, and reconstructed vessel wall with elastin and collagen fibers. The cellular and extracellular components in the patch had increased to levels similar to those in native tissue at 6 months.The poly(lactic-co-glycolic acid)-collagen microsponge patch with and without precellularization showed good histological findings and durability. This patch shows promise as a bioengineered material for accelerate in situ cellularization and the regeneration of autologous tissue in cardiovascular surgery.