INTRODUCTION: Cell death upon implantation in vivo is a major obstacle in tissue engineering and cell therapy. Implanting cells as 3D multi-cellular spheroids rather than single cells can improve cell survival. In addition, co-culturing vascular cells within spheroids may further improve in vivo cell survival by maximizing vascularization through inosculation. This project aims to combine liver progenitor cells (LPCs) with vascular cells to form capillaries within 3D multicellular spheroids to enhance LPC survival post implantation.
METHODS: Murine LPCs, liver sinusoidal endothelial cells (LSECs) and adipose derived mesenchymal stem cells (ASCs) were investigated for their spheroid forming ability using 20,000 cells/well in 20% methylcellulose. Proliferation and apoptosis were examined via immunohistochemistry over 10 days. Various cell types were then co-cultured to assess their ability to form a single spheroid, and if capillaries could be formed within the spheroid.
RESULTS: All cell types formed a single spheroid/well with increasing apoptosis and decreasing proliferation over 10d. In co-cultures, capillaries (CD 31 +ve) were seen in spheroids containing LPCs/LSEC and LPC/LSEC/ASC.
CONCLUSION: Co-culturing LPCs with vascular cells demonstrates capillary formation within the spheroid in vitro. Current in vivo implantation experiments within a murine vascularized tissue engineering chamber will determine if inosculation occurs between these spheroid capillaries and sprouting capillaries within the in vivo chamber and if the survival of the LPCs within the chamber is enhanced when co-cultured vascular cell/LPC spheroids are implanted.