Wang, LiminZhao, LiangDetamore, Michael S.2017-06-162017-06-162011-10Wang, L., Zhao, L., & Detamore, M. S. (2011). Human umbilical cord mesenchymal stromal cells in a sandwich approach for osteochondral tissue engineering. Journal of Tissue Engineering and Regenerative Medicine, 5(9), 712–721. http://doi.org/10.1002/term.370https://hdl.handle.net/1808/24530This is the peer reviewed version of the following article: Wang, L., Zhao, L., & Detamore, M. S. (2011). Human umbilical cord mesenchymal stromal cells in a sandwich approach for osteochondral tissue engineering. Journal of Tissue Engineering and Regenerative Medicine, 5(9), 712–721. http://doi.org/10.1002/term.370, which has been published in final form at http://doi.org/10.1002/term.370. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Cell sources and tissue integration between cartilage and bone regions are critical to successful osteochondral regeneration. In this study, human umbilical cord mesenchymal stromal cells (hUCMSCs), derived from Wharton’s jelly, were introduced to the field of osteochondral tissue engineering and a new strategy for osteochondral integration was developed by sandwiching a layer of cells between chondrogenic and osteogenic constructs before suturing them together. Specifically, hUCMSCs were cultured in biodegradable poly-l-lactic acid scaffolds for 3 weeks in either chondrogenic or osteogenic medium to differentiate cells toward cartilage or bone lineages, respectively. A highly concentrated cell solution containing undifferentiated hUCMSCs was pasted onto the surface of the bone layer at week 3 and the two layers were then sutured together to form an osteochondral composite for another 3 week culture period. Chondrogenic and osteogenic differentiation was initiated during the first 3 weeks, as evidenced by the expression of type II collagen and runt-related transcription factor 2 genes, respectively, and continued with the increase of extracellular matrix during the last 3 weeks. Histological and immunohistochemical staining, such as for glycosaminoglycans, type I collagen and calcium, revealed better integration and transition of these matrices between two layers in the composite group containing sandwiched cells compared to other control composites. These results suggest that hUCMSCs may be a suitable cell source for osteochondral regeneration, and the strategy of sandwiching cells between two layers may facilitate scaffold and tissue integration.Umbilical cordStromal cellsOsteochondral tissue engineeringIntegrationArticle10.1002/term.370PMC3770475openAccess