Thus, an islet regenerating protein (Reg‐1) or the Wnt family member 5A (Wnt5a) regulated the activation of ISCs via signalling pathways including the phosphorylation of Akt, Erk and Smad18; islet dysfunction caused by vitamin A deficiency was attributed to the induction of ISC activation via retinol‐binding protein19; and in vitro co‐culture of isolated islets with ISCs modified their insulin secretory responses.20, 21. This evidence concerns the gene WNT5A and vitamin A deficiency.