Pericytes were originally discovered more than100 years ago as contractile cells surrounding the endothelial cells of small blood vessels. Anatomists have later on strictly defined pericytes as cells sharing a basal membrane with the endothelium. However, current literature meanwhile frequently uses the term pericyte to denote any microvascular periendothelial mesenchymal cell. Due to the lack of exclusive markers, pericytes are now defined by a combination of location, morphology and gene expression. Those pericytes are attracting increasing attention as important regulators during development and during normal and deranged organ function.
Four minireviews written by experts in the fields summarize the present knowledge about the physiological function and pathophysiological role of pericytes in the eye, heart, kidney and liver.