Author version made available in accordance with the publisher's policy.Within the pancreatic islet, the beta cell represents the ultimate biosensor. Its central function is
to accurately sense glucose levels in the blood, and consequently release appropriate amounts of
insulin. As the only cell type capable of insulin production, the beta cell must balance this crucial
workload with self-preservation and, when required, regeneration. Evidence suggests that the
beta cell has an important ally in intra-islet endothelial cells. As well as providing a conduit for
delivery of the primary input stimulus (glucose) and dissemination of its most important effector
(insulin), intra-islet blood vessels deliver oxygen to these dense clusters of metabolically active
cells. Furthermore, it appears that endothelial cells directly impact insulin gene expression,
secretion and beta cell survival.
This review discusses the molecules and pathways involved in the crosstalk between beta cells
and intra-islet endothelial cells. The evidence supporting the intra-islet endothelial cell as an
important partner for beta cell function is examined to highlight the relevance of this axis in the
context of type 1 and type 2 diabetes. Recent work which has established the potential of
endothelial cells or their progenitors to enhance the reestablishment of glycaemic control
following pancreatic islet transplantation in animal models is discussed
