Engineering pre-vascularized 3D tissue and rapid vascular integration with host blood vessels via co-cultured spheroids-laden hydrogel

Abstract

Recent advances in regenerative medicine and tissue engineering have enabled the biofabrication of three-dimensional (3D) tissue analogues with the potential for use in transplants and disease modeling. However, the practical use of these biomimetic tissues has been hindered by the challenge posed by reconstructing anatomical-scale micro-vasculature tissues. In this study, we suggest that co-cultured spheroids within hydrogels hold promise for regenerating highly vascularized and innervated tissues, both in vitro and in vivo. Human adipose-derived stem cells (hADSCs) and human umbilical vein cells (HUVECs) were prepared as spheroids, which were encapsulated in gelatin methacryloyl (GelMA) hydrogels to fabricate a 3D pre-vascularized tissue. The vasculogenic responses, extracellular matrix (ECM) production, and remodeling depending on parameters like co-culture ratio, hydrogel strength, and pre-vascularization time for in vivo integration with native vessels were then delicately characterized. The co-cultured spheroids with 3:1 ratio (hADSCs/HUVECs) within the hydrogel and with a pliable storage modulus showed the greatest vasculogenic potential, and ultimately formed in vitro arteriole-scale vasculature with a longitudinal lumen structure and a complex vascular network after long-term culturing. Importantly, the pre-vascularized tissue also showed anastomotic vascular integration with host blood vessels after transplantation, and successful vascularization that was positive for both CD31 and alpha-smooth muscle actin covering 18.6 ± 3.6 µm2 of the luminal area. The described co-cultured spheroids-laden hydrogel can therefore serve as effective platform for engineering 3D vascularized complex tissues.

Biofabrication of 3D adipose tissue via assembly of composite stem cell spheroids containing adipo-inductive dual-signal delivery nanofibers

“…Furthermore, while biofabrication strategies utilizing spheroids in tissue engineering still face diffusion constraints, we anticipate implantation with pre-vascularized construct may resolve these problems. Previous studies have addressed this by encapsulating co-culture spheroids in hydrogels to create pre-vascularized tissue [57], which can potentially be applied to engineer macroscopic adipose tissue using our technique. Taken together, by effectively leveraging the advantages of our techniques and addressing the limitations, they hold promise to serve as potent tissue engineering approaches.…”