Vascularization of the Pancreas: An Evolving Role From Embryogenesis to Adulthood

Abstract

In most organs, blood vessels provide a continuous supply of oxygen, nutrients, and growth factors. In the case of pancreas, such environmental signals are crucial for both the development and the function of the tissue (1). Other evidence supports the fact that paracrine signals participate in this process. Based on the existence of such signals, blood vessels are intuitively supportive for organ growth. One illustration of such positive signal is that, at early stages of development, the vascular endothelium is an inductive signal for insulin expression in the endoderm (2). However, recent findings revisited this concept and demonstrated that the previously described positive role of blood vessels is not general. Magenheim et al. (3) found, using both genetic and pharmacological approaches, that blood vessels can have a restrictive role on pancreas development at later stages. Because of this controversial effect of blood vessels at different time points of development, more investigations have been necessary to clarify the precise effect of vascularization. The pathological impact of such discoveries is important as blood vessels have been shown to be key elements in diabetes (4) and pancreatic cancer (5). During the last decade, a number of works have shed light on the role of vascular paracrine factors on pancreas development. This includes sphingolipid sphinsosine-1 …