08/10/13Histol Histopathol, Vol 24, Díaz-Flores et al. HISTOLOGY AND HISTOPATHOLOGY Cellular and Molecular Biology Review Pericytes. Morphofunction, interactions and pathology in a quiescent and activated mesenchymal cell niche L. Díaz-Flores1, R. Gutiérrez1, J.F. Madrid3, H. Varela1, F. Valladares1,4, E. Acosta2, P. Martín-Vasallo2 and L. Díaz-Flores Jr1 1Department of Anatomy, Pathology, Histology and Radiology, Faculty of Medicine, University of La Laguna, Tenerife, Spain, 2Developmental Biology Laboratory, Department of Biochemistry and Molecular Biology, University of La Laguna, Tenerife, Spain, 3Department of Cell Biology and Histology, Faculty of Medicine, University of Murcia, Murcia, Spain and 4CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain. Offprint requests to: L. Díaz-Flores, Departamento de Patología, Facultad de Medicina, Universidad de La Laguna, Tenerife, Spain. e-mail:
[email protected] Summary. We review the morphofunctional characteristics of pericytes and report our observations. After a brief historical background, we consider the following aspects of pericytes: A) Origin in embryonic vasculogenesis (mesenchymal stem cells, neurocrest and other possible sources) and in embryonic and postnatal life angiogenesis (pre-existing pericytes, fibroblast/ myofibroblasts and circulating progenitor cells). B) Location in pericytic microvasculature and in the other blood vessels (including transitional cell forms and absence in lymphatic vessels), incidence (differences depending on species, topographical location, and type and stage of vessels) and distribution (specific polarities) in blood vessels. C) Morphology (cell body, and longitudinal and circumferential cytoplasmic processes), structure (nucleus, cytoplasmic organelles and distribution of microtubules, intermediate filaments and microfilaments) and www.hh.um.es/pdf/Vol_24/24_7/Diaz-Flores-24-909-969-2009.pdf 1/2 diabetic microangiopathy. H) Peculiar pericyte types. preadipocytes. I) Involvement in pathological processes. Vol 24.um. intervention in coagulation. components and functions. F) Molecular expression (pericyte marker identification). fibroblast/myofibroblasts. 909-969 (2009) Key words: Pericytes. macrophage-like properties. chronic venous insufficiency. vascular smooth muscle and myointimal cells. immunological defense. as progenitor cells with great mesenchymal potential. pericyte-derived tumors. Alzheimer disease and multiple sclerosis. Mesenchymal cells. This mesenchymal capacity is seen in a broad section on the perivascular mesenchymal cell niche hypothesis and in the concept of pericyte and EC “marriage and divorce”. fibrosis. and with extracellular matrix) and plasticity. Histol Histopathol 24. Angiogenesis. tumor angiogenesis and tumoral cell metastasis. formation. regulation of vascular tone and maintenance of local and tissue homeostasis (contractile capacity and vessel permeability regulation). E) Contacts with endothelial cells (ECs) (peg and socket arrangements. such as hepatic stellate cells (Ito cells). adherent junctions and gap junctions) and with basal membrane (adhesion plaques). chondroblasts. such as repair through granulation tissue. lymphedema distichiasis. such as vessel stabilization.hh. J) Clinical and therapeutic implications (de-stabilization of vessels or formation of a stable vasculature).es/pdf/Vol_24/24_7/Diaz-Flores-24-909-969-2009. bone marrow reticular cells and mesangial cells. Stem cell niche www. surface (caveolae system). Díaz-Flores et al.pdf WebConnect Ads 2/2 . pulmonary hypertension.08/10/13 Histol Histopathol. odontoblasts. D) Basement membrane disposition. participation in mechanisms that regulate the quiescent and angiogenic stages of blood vessels (including the behaviour of pericytes during sprouting angiogenesis and intussuceptive vascular growth. atherosclerosis and calcific vasculopathy. matrix protein synthesis. G) Functions. originating other pericytes. osteoblasts. as well as pericyte interactions with endothelium and other cells.