Pericytes in the renal vasculature: roles in health and disease

Abstract

In the dense circulatory system of the kidney, as in all vascularized tissues, pericytes enwrap capillaries and microvessels to regulate angiogenesis, stabilize microvascular networks and control blood flow by vasoconstriction. Specialized renal pericytes known as mesangial cells provide physical support to glomerular capillaries, whereas a subset of juxtaglomerular arteriolar pericytes control the local blood pressure in the glomerulus via contraction and influence systemic blood pressure by secreting renin. Similar to pericytes from many other organs, cultured human renal pericytes give rise to mesenchymal stem/stromal cells, suggesting a role of perivascular cells in renal homeostasis and regeneration. On the other hand, pericytes directly contribute to renal fibrosis, and mesangial cells may have an essential role in the development of glomerulosclerosis and other nephropathies. From their early emergence in the renal embryonic rudiment to their distribution in diverse perivascular niches in the adult organ, we review the anatomy and function of pericytes in the healthy and diseased kidney. Many aspects of the ontogeny, specification and functional specialization of renal pericytes remain elusive. The development of powerful models in the easily accessible and genetically tractable zebrafish will help to uncover the multiple facets of these cells.

Phenotypic, Transcriptional, and Functional Analysis of Liver Mesenchymal Stromal Cells and Their Immunomodulatory Properties

“…It is noteworthy that the genes and gene sets that are related to tissue integrity and homeostasis, which are shared by L‐MSCs, are up‐regulated in the kidney allografts of the simultaneous liver‐kidney transplant recipients compared with the kidney allografts of solitary kidney transplant recipients . Pericytes, a heterogeneous population of mesenchymal cells found in all vascularized tissues, are phenotypically indistinguishable from cultured MSCs and share the same trilineage differentiation potential with the latter, suggesting that they are the in vivo equivalents of MSCs . Such similarities have been demonstrated in pericytes isolated from the kidney, skeletal muscle, pancreas, adipose tissue, placenta, and BM .…”

“…(8) Pericytes, a heterogeneous population of mesenchymal cells found in all vascularized tissues, are phenotypically indistinguishable from cultured MSCs and share the same trilineage differentiation potential with the latter, suggesting that they are the in vivo equivalents of MSCs. (46) Such similarities have been demonstrated in pericytes isolated from the kidney, skeletal muscle, pancreas, adipose tissue, placenta, and BM. (47) It remains to be shown whether pericytes in the liver share the same phenotype and whether L-MSCs actually mobilize to other sites or if the observed effects are mediated by soluble factors.…”

Pericytes for Therapeutic Bone Repair

“…Although recognized in all tissues with canonical markers and characteristic perivascular distribution, pericytes and adventitial cells represent heterogeneous cell populations which also exhibit organ-restricted anatomic, phenotypic, and functional specializations, the complexity of which is being gradually uncovered [11]. Regarding bone formation, we have recently identified novel surface markers which typify PSC subsets endowed with higher osteogenic potential (Ding, Meyers et al, unpublished results), as was already recently done for pro-fibrotic ability [10] and chondrogenic capacity [56].…”

“…It was, however, not before the first decade of this century that definitive experimental evidence was gained that pericytes are native ancestors of mesenchymal stem cells (MSC), the existence of which had been previously documented exclusively in long-term cultures of vascularized organs [6]. Pericytes can differentiate into chondrocytes, adipocytes and osteocytes, regardless of their tissue of origin [6–8], as well as skeletal and cardiac muscle [6, 9], and myofibroblasts at the origin of pathologic fibrosis [10, 11]. Pericytes also support hematopoiesis [12–16] and can modulate immune-inflammatory reactions [17].…”

Perivascular Mesenchymal Progenitors for Bone Regeneration

“…As we have showed, renin-producing cells in afferent juxtaglomerular arterioles are also specialized pericytes. 43,55 Conversely, other potentials of pericytes exhibit an amazing lack of organ specificity; for instance, while the hematopoietic stem cell niche in the bone marrow is well recognized to be mostly composed of pericytes, the same cells purified from skeletal muscle and adipose tissue exhibit a dramatic ability to sustain hematopoietic stem cells in vitro. 56,57…”