INVESTIGATION OF THE ROLE OF PERICYTES IN THE IN VITRO MODEL OF BIOARTIFICIAL TISSUE FORMATION FROM hPSC-DERIVED CARDIOVASCULAR CELL TYPES

Cardiac grafts produced by combining human pluripotent stem cell (hPSC)-derivatives and tissue engineering are a promising therapeutic option for the replacement of cardiomyocytes (CM) lost due to myocardial infarction. Currently, the vascularization and maturation of such grafts are the most critical aspects. In addition to endothelial cells (EC), pericytes (PC) are known to play a crucial role in vessel development and stabilization. Here, an hPSC-derived PC differentiation protocol is shown as well as an in vitro model for the investigation of the role of PCs in hPSC-derived bioartificial cardiac tissues (BCT). In the established differentiation protocol, the population giving rise to PCs (CD31-/PDGFRβ+) represented up to 94% of all cells and could be further purified via cell sorting. The obtained hPSC-PCs exhibited functional characteristics of PCs in co-culture assays, and showed similar gene expression profile to primary PCs. Differentiated hPSC-PCs were used w/ or w/o purified hPSC-ECs to generate BCTs and to address their effect on tissue morphology, metabolism, and electrophysiological parameters compared to control tissues containing primary fibroblasts (Fb). Interestingly, tissues with hPSC-PCs exhibited equivalent contraction forces compared to controls, but more organized sarcomere structures as well as improved longitudinal cell- and extracellular matrix orientation. Furthermore, the beating frequency and passive forces showed native-like values. Addition of hPSC-ECs resulted in spontaneously formed and maintained endothelial network structures, which were distributed throughout the BCTs and the involvement of PCs in such structures was demonstrated. The characterized and functional hPSC-PCs together with hPSC-derived CMs and ECs represent a promising cell source for myocardial tissue replacement therapy. Their dual ability in supporting EC function and matrix remodeling during tissue maturation makes them a favorable candidate to replace primary Fbs.