Integration of Nephron and Ureteric Bud Progenitors in Kidney Scaffolds Enhances Nephrogenesis and Facilitates Nephron-Collecting Duct Fusion

Background: End-Stage Renal Disease (ESRD) has become a worldwide healthcare problem affecting ~10% of the population. The lack of availability of transplantable organs warrants research into technologies to generate kidney tissues. Here, we report that reconstituted kidney scaffolds with human pluripotent stem cells (hPSCs) derived nephron progenitors (NPs) and ureteric bud progenitors (UBPs) potentiate nephrogenesis that gave rise to patent vasculature with evident erythrocytes and functional nephrons with collecting ducts fusion. Methods: We initially evaluated kidney organoids generated by integrating NPs and UBPs differentiated from hPSCs in-vitro. Subsequently, rat acellular scaffolds were seeded with NPs and UBPs and cultured in bioreactor for 10 days. The recellularized scaffolds were then evaluated for endothelialization, nephron and collecting duct maturation. Next, reconstructed kidney scaffolds were engrafted in partially nephrectomized NSG mice. Three weeks post-engraftment, the constructs were analyzed for vascularization, tubule fusion, and nephron secretory function. Results: The recellularized kidney scaffolds exhibited advanced nephron and collecting duct structures, featuring perfused UEA1-positive lumenized endothelial networks. Integration of NPs and ureteric bud progenitors UBPs resulted in significant upregulation of nephron- and collecting duct-specific genes within the recellularized scaffolds. Upon engraftment into NSG mice, the constructs became vascularized with both host- and graft-derived endothelial networks, as evidenced by the presence of erythrocytes. Nephron segments and collecting ducts exhibited interconnection and secreted human-specific protein, which was detected in recipient urine. The presence of erythrocytes within graft-derived vasculature and the detection of human-specific protein in mouse urine strongly indicates successful anastomosis between graft and host tissues. Conclusion: This study demonstrates that NPs and UBPs derived from hPSCs can effectively recellularize acellular kidney scaffolds. Upon engraftment into partially nephrectomized NSG mice, the constructs exhibited increased maturation, further supporting their potential for regenerative applications. Funding: NIDDK Support