Measurement of spontaneous C-peptide secretion showing that the mesenchymal stem cells of Wharton’s jelly differentiate into insulin-producing cells. The expression of C-peptide was greater among differentiated IPCs versus undifferentiated MSCs (Figure 3A). The level of C-peptide expression increased several-fold from MSCs cultured in SFM-A, SFM-B and finally SFM-C (Figure 3B). *, P ≪ 0.05 compared to the non-differentiated cells in A and compared to SFM-A in B. †,P ≪ 0.05 compared to SFM-B.