Biological characterization of cell spheroids assisted by lipid-conjugated heparin

Abstract

Adipose-derived stem cells (ADSCs) can be widely used in the field of regenerative medicine with its wide range of sources and multipotency. 3-dimensional (3D) cultures that are able to provide stem cell niche are more suitable because stem cells tend to lose stemness in traditional 2-dimensional (2D) culture. In addition, the spheroid improves the therapeutic effect by increasing the amount of cells remaining in cell therapy. In this study, we devised a new method of making spheroids using lipid-conjugated heparin without scaffolds. This method can make spheroids faster than other existing 3D spheroids. The hADSCs cultured in this way improved metabolic activity and maintained the stemness longer than the hADSCs cultured by hanging drop, one of the conventional methods. In addition, lipid-conjugated heparin did not affect cell-cell junction formation and VEGF, PDGF gene expression of hADSCs. This study also confirmed the effect of co-culture of hADSC and HUVEC. Co-culture with HUVEC revealed that metabolic activity of hADSC, cell-cell jungtion formation, and the gene expression of VEGF were improved. However, in the case of PDGF, co-culture with HUVEC resulted in decreased gene expression. In addition, secretion of VEGF was enhanced in lipid-conjugated heparin spheroids.