S-SDF-1诱导免疫微环境促Sox10+神经嵴干细胞原位血管再生机制研究

There is a critical clinical need for small-diameter vascular grafts. Currently used small-diameter vascular grafts have a poor long-term performance, limiting their utility and success. Recently recruiting endogenous stem cells for in situ blood vessel regeneration is a novel and efficient approach in vascular tissue engineering. However, the negative remodeling of the grafts are observed due to the poor bioactivity of the scaffolds and the pro-inflammatory effects of inflammatory cells on the recruitment, and the source and differentiation fate of the recruited cells are not determined. Biomaterial-based immunomodulation strategies are becoming the hot topic of tissue engineering. Therefore, we will investigate how the microfibrous scaffolds treated with a protease-resistant form of SDF-1, i.e., S-SDF-1(S4V), shape the immune microenvironment to improve the vascular regeneration. The scaffolds will induce a pro-regenerative response, characterized by increasing the population and proportion of T helper 2 cells regulated by an mTORC2 pathway that recruites Sox10+ neural crest stem cells, which is critical for functional vascular regeneration. And the source and differentiation fate of the recruited cells will be investigated using the lineage tracing. These results will provide a rational basis for better vascular graft development and clinical translation.

小口径人工血管临床需求大，但远期通畅率低导致临床应用受到限制。近年来，原位组织工程技术试图通过招募内源性干细胞诱导血管再生，但因血管支架材料生物活性欠佳、炎性反应明显，影响管壁重构，且招募干细胞来源和命运不明。免疫调节生物材料成为组织工程当前研究的热点，本研究以改性生物材料构建诱导组织再生的免疫微环境为基础，拟将体内耐酶解S-SDF-1(S4V)结合至可降解血管支架，调控局部免疫微环境，通过mTORC2信号通路促进T淋巴细胞发生极化效应，Th2细胞数量和比例上调，从而招募Sox10+神经嵴干细胞参与血管再生，同时明确内源性Sox10+神经嵴干细胞来源及命运，为推进小口径组织工程血管再生机制研究和临床转化提供依据。

背景：血管移植广泛应用于冠状动脉搭桥术、血液透析、外周动脉搭桥术和先天性心脏病等领域。实验采用多种合成材料和天然材料制作组织工程血管移植物。在本研究中，我们在小型猪体内研究了组织工程技术，以制备脱细胞的自体细胞外基质移植物，作为小口径血管搭桥手术的血管移植物。.研究内容：雌性小型猪(n=8，体重25~30 kg)皮下埋入聚四氟乙烯管4周，制成直径3.9 mm的自体组织管道。然后用CHAPS脱细胞溶液对它们进行脱细胞。通过磺化NHS/EDC将肝素共价连接到脱细胞组织管道上。我们将这些脱细胞的、完全自体细胞外基质为基础的移植物植入小型猪的颈动脉，然后在植入后1个月或2个月处死猪，评估通畅率和移植物的组织学。.关键数据：术后1个月通畅率为100%(5/5)，移植物内径为3.43±0.05 mm(n=5)。术后2个月通畅率67%(2/3)，移植物内径2.32±0.14 mm(n=3)。组织学染色证实，在2个月的样本中成功地进行了细胞渗透，胶原和弹性蛋白沉积。移植物内腔内可见单层内皮细胞，而移植物壁内以平滑肌细胞为主。.科学意义：完全自体脱细胞管道具有良好的力学性能，可在小型猪模型中改建成新生动脉。这项在大型动物模型中的概念验证研究非常令人鼓舞，表明这是一个高度可行的想法，值得在临床移植之前在非人类灵长类动物中进一步研究。