Liver Changing to Islets

Sao Paulo, Brazil -

It is known that oval cells of the liver, which act as stem cells, can differentiate into hepatocytes and bile duct epithelium. Oval cells expand when hepatocyte damage occurs and hepatocye mitogenesis is concurrently inhibited. Previously it was published that these oval cells, which ironically also express hematopoietic stem cell markers such as CD34, CD90 and stem cell antigen, can "transdifferentiate" into islet-like cells when they are exposed to environments containing high concentrations of glucose. In fact the Florida-based company Ixion is actually trying to commercialize these types of approaches.

In a recent paper (Leite et al. Fibronectin and laminin induce expression of islet cell markers in hepatic oval cells in culture. Cell Tissue Res. 2006 Dec 6) it was demonstrated that extracting oval cells of the liver and growing them in the presence of fibronectin or laminin is able to induce their differentiation into islet-like cells that generate insulin and express islet-specific transcription factors such as PDX-1 and PAX-6.

It will be interesting to see if transdifferentiation generated islet-like cells have efficacy in mouse models of diabetes such as the non-obese diabetic mouse (NOD) or the streptozoicin-induced diabetes model.