Universidad de Murcia, Departamento de Biologia Celular e Histiologia
Abstract
The proper delivery of blood is essential for
healthy neuronal function. The anatomical substrate for
this precise mechanism is the neurovascular unit, which
is formed by neurons, glial cells, endothelia, smooth
muscle cells, and pericytes. Based on their particular
location on the vessel wall, morphology, and protein
expression, pericytes have been proposed as cells
capable of regulating capillary blood flow. Pericytes are
located around the microvessels, wrapping them with
their processes. Their morphology and protein
expression substantially vary along the vascular tree.
Their contractibility is mediated by a unique
cytoskeleton organization formed by filaments of actin
that allows pericyte deformability with the consequent
mechanical force transferred to the extracellular matrix
for changing the diameter. Pericyte ultrastructure is
characterized by large mitochondria likely to provide
energy to regulate intracellular calcium concentration
and fuel contraction. Accordingly, pericytes with
compromised energy show a sustained intracellular
calcium increase that leads to persistent microvascular
constriction. Pericyte morphology is highly plastic and
adapted for varying contractile capability along the
microvascular tree, making pericytes ideal cells to
regulate the capillary blood flow in response to local
neuronal activity. Besides the vascular regulation,
pericytes also play a role in the maintenance of the
blood-brain/retina barrier, neovascularization and
angiogenesis, and leukocyte transmigration. Here, we
review the morphological and functional features of the
pericytes as well as potential specific markers for the
study of pericytes in the brain and retin