The role of pericytes in blood-vessel formation and maintenance

Abstract

Blood vessels are composed of two interacting cell types. Endothelial cells form the inner lining of the vessel wall, and perivascular cells--referred to as pericytes, vascular smooth muscle cells or mural cells--envelop the surface of the vascular tube. Over the last decades, studies of blood vessels have concentrated mainly on the endothelial cell component, especially when the first angiogenic factors were discovered, while the interest in pericytes has lagged behind. Pericytes are, however, functionally significant; when vessels lose pericytes, they become hemorrhagic and hyperdilated, which leads to conditions such as edema, diabetic retinopathy, and even embryonic lethality. Recently, pericytes have gained new attention as functional and critical contributors to tumor angiogenesis and therefore as potential new targets for antiangiogenic therapies. Pericytes are complex. Their ontogeny is not completely understood, and they perform various functions throughout the body. This review article describes the current knowledge about the nature of pericytes and their functions during vessel growth, vessel maintenance, and pathological angiogenesis.

Partial persistence of exercise-induced myocardial angiogenesis following 4-week detraining in the rat

“…3). Figure 3b, shows a pericyte detached from the vessel wall, a Wnding which is generally associated with the vessel hyperdilatation that precedes the formation of new capillaries (Bergers and Song 2005).…”

Oscillatory Strain Promotes Vessel Stabilization and Alignment through Fibroblast YAP‐Mediated Mechanosensitivity

“…This conclusion is also supported by the higher number of αSMA‐ and PDGFRβ‐positive cells seen surrounding the oscillatory stretched vessels. In the coronary artery system, αSMA expression was found near large and mature arteries,18 and is considered a marker of mural cells differentiation into smooth‐muscle cells and hence, vessel maturation 29. In addition, collagen IV deposition was aligned in the same manner as the cells, leading us to conclude that endothelial microvessels forming under oscillatory‐stretch are more mature and stable, and surrounded by aligned ECM.…”

“…During this stage, EC proliferation decreases, and mural cells differentiation increases 18, 28, 29. These processes are facilitated by secretion of various cytokines.…”

Amyloid‐beta 1‐40 is associated with alterations in NG2+ pericyte population ex vivo and in vitro

“…These cells are very dynamic and versatile. In their mature state, they play a key role in vessel stabilization and vessel permeability, but in response to changes in their environment, pericytes become activated and take part in events such as vascular remodelling, inflammation (Bergers & Song, 2005; Paul et al., 2012) and clearance of neurotoxic substances (including Aβ) (Zlokovic, 2008). Hence, loss of pericytes leads not only to deleterious events, such as impaired BBB or vessel leakage (Quaegebeur, Segura & Carmeliet, 2010), but could also underlie the accumulation of Aβ in the AD brain.…”