Islet replacement holds promise as therapy for diabetes mellitus. However, the major limitation in this line of therapy is the supply of donor tissue. In order to overcome this limitation, scientists are researching how endocrine tissue can be expanded and a possible solution includes in vitro β-cell production. This requires an understanding of the normal developmental processes that regulate islet formation.

In a study carried out by Cole et al., at the University of Arizona, AZ, USA, pancreas development in sheep and in humans have been compared. The authors have focussed on the process of pancreatic islet development, in which ductal cells start to specialize and undergo a mechanism termed epithelial-mesenchymal transition (EMT). In this mechanism ductal cells group or migrate as single cells from the ductal epithelium into the surrounding pancreatic mesenchyme and aquire a beta cell phenotype. In this process they additionally express vimentin as a marker of mesenchyme. Their findings provide strong evidence that the movement of β-cells from the pancreatic ductal epithelium involves an EMT and provides promising new insight to refine strategies for β-cell expansion in vitro for islet replacement therapy. Journal of Endocrinology, DOI: 10.1677/JOE-09-0072