Differentiation of arterioles and capillaries in human blood vessel organoids with decellularized splenic matrix.

Vascular organoids show great promise for promoting angiogenesis post-myocardial infarction, but current organoid culture methods only form capillaries in vitro, while relying on Matrigel faces challenges due to its undefined composition and potential immune reactions, which hinder clinical translation. To address this issue, a splenic extracellular matrix-derived thermoresponsive hydrogel (SpGel) with type I collagen was developed. This matrix has defined components, avoids the immune response triggered by viruses in Matrigel, and demonstrates the ability to enhance arterioles and capillary differentiation in blood vessel organoids. The gelation time of SpGel/col-I was comparable to that of typical Matrigel/col-I matrix. Additionally, SpGel/col-I significantly boosted angiogenesis of human blood vessel organoids compared to the Matrigel/col-I group. Single-cell sequencing revealed significant upregulation of ITGA5 and ITGB1 in the endothelial cell population within the SpGel/col-I group, and the increase in endothelial and mural cell differentiation was mainly associated with the VEGF and PDGFB signaling pathways. To verify the in vivo reparative effects, SpGel/col-I with hBVOs were co-transplanted into a myocardial infarction animal model and showed improved cardiac function, reduced myocardial fibrosis, and enhanced neovascularization. In summary, we successfully improved the differentiation of arterioles and capillaries in human blood vessel organoids with decellularized splenic matrix, providing an ideal therapeutic approach for repairing infarcted myocardium in clinical settings.