Pre-vascularization of biomimetic 3-D scaffolds via direct co-culture of human umbilical cord derived osteogenic and angiogenic progenitor cells

Abstract

A major barrier in the bone tissue-engineered construct (TEC) is the nonexistence of a vasculature system, which compromises the survival of the transplanted cells and limits their clinical use. The current work aimed at developing pre-vascularized functional constructs by direct co-culture of human Wharton's jelly mesenchymal stem cells (WJ-MSCs) and human umbilical vein endothelial cells (HUVECs) on 3-D biomimetic nano-hydroxyapatite/chitosan/gelatin (nHA/Cs/Gel) scaffolds. Cells were seeded in mono- and co-culture circumstances for over 3 weeks. Cell morphology and attachment, differentiation, proliferation, and formation of the capillary-like structure were assessed by different histomorphological, biochemical, and molecular tests at specific time points. As shown by SEM, H&E, and DAPI staining, cells adhered and spread well onto scaffold surfaces. Mineralization and ALP activity in co-cultured cells were higher significantly compared to those of monocultures. This activity also was found to be concurrent with the upregulation of osteogenic and angiogenic-related markers at the gene and protein levels at selected time points. Moreover, based on the results of IHC staining, the co-culture system favored the formation of a vessel-like structure. Overall, our novel approach of co-culturing two types of cells with the same origin (i.e., WJ-MSCs and HUVECs) resulted in pre-vascularized 3-D nHA/Cs/Gel scaffolds and tailored them to future clinical requirements.