The generation of insulin-producing cells from embryonic stem cells--a discussion of controversial findings.

The derivation of insulin-producing cells from embryonic stem (ES) cells has been controversially described. Whereas several authors showed successful differentiation of mouse ES cells into islet-like clusters, others could not confirm the results. Here, we present a detailed comparison of the various strategies used to generate pancreatic cells with respect to protocols and differentiation factors and give an explanation of the contradictory findings. It is suggested that the selection or enrichment of ES-derived nestin-positive cells should be avoided, since these cells are already committed to a neural fate before pancreatic differentiation is induced.