Restoration of chondrogenic properties of degenerative nucleus pulposus cells by repeated co-culture with adipose-derived stem cells

We used porous membranes for co-culturing adipose-derived stem cells (ASCs) with nucleus pulposus cells (NPCs) to investigate whether repeated co-cultures restored the chondrogenic properties of degenerative NPCs (dNPCs). Human dNPCs were co-cultured with ASCs for 1 week and co-cultured again with new ASCs for 1 week. The expression levels of chondrogenic genes and GAGs were significantly higher in second co-cultured dNPCs than those in the first co-cultured dNPCs and in dNPCs cultured alone, respectively. After six weeks of in vivo transplantation, compared to first co-cultured dNPCs, second co-cultured dNPCs showed a significantly higher cartilage tissue formation.