Diaz-Flores Lucio, Gutierrez Ricardo, Madrid Juan Francisco, Varela Hilda, Valladares Francisco, Diaz-Flores Lucio
Department of Pathology, Histology and Radiology, School of Medicine, La Laguna University, Canary Islands, Spain.
Front Biosci (Landmark Ed). 2009 Jan 1;14(4):1433-70. doi: 10.2741/3317.
Macrophage recruitment and proliferation of both small vessels (endothelium and pericytes) and fibroblast-myofibroblasts are the fundamental and provisional cellular findings in repair through granulation tissue (RTGT).Endothelium and pericytes of preexisting microvasculature may act as progenitor cells of new endothelial cells and new pericyte-fibroblast-myofibroblasts, respectively.Likewise, fibroblasts may be progenitors of themselves, and of myofibroblasts and pericytes. Moreover, all these cells may originate from circulating progenitor cells or other progenitor cells..According to this extensive cellular plasticity, this work reviews the adult stem cells (ASC) and transit- amplifying cells (TAC) related to the principal cellular components of RTGT.Moreover, we hypothesize that the perivascular region, with a heterogeneous pericyte-like cellular population, including pericytes, perivascular fibroblasts and homing cells from the bone marrow (fibrocytes and bone marrow mesenchymal cells), is the niche of progenitor cells in RTGT and the substrate of regulatory mechanisms (perivascular niche hypothesis).We also highlight RTGT as a "paracrine transitional organ" during involutive phenomena and cellular differentiation.Furthermore, we consider the combined role of both systems (ASC-TAC and RTGT) in tissue engineering and in pathological processes, such as fibrosis, organization, atherosclerosis, and tumor stroma.
巨噬细胞募集以及小血管（内皮细胞和周细胞）和成纤维细胞-肌成纤维细胞的增殖，是通过肉芽组织进行修复（RTGT）过程中的基本且临时的细胞表现。既有微血管的内皮细胞和周细胞可能分别作为新内皮细胞以及新周细胞-成纤维细胞-肌成纤维细胞的祖细胞。同样，成纤维细胞可能是其自身以及肌成纤维细胞和周细胞的祖细胞。此外，所有这些细胞可能源自循环祖细胞或其他祖细胞。根据这种广泛的细胞可塑性，本文综述了与RTGT主要细胞成分相关的成体干细胞（ASC）和过渡扩增细胞（TAC）。此外，我们假设血管周围区域，具有包括周细胞、血管周围成纤维细胞以及来自骨髓的归巢细胞（纤维细胞和骨髓间充质细胞）在内的异质性类周细胞群体，是RTGT中祖细胞的生态位以及调节机制的底物（血管周围生态位假说）。我们还强调RTGT在退化现象和细胞分化过程中作为“旁分泌过渡器官”的作用。此外，我们考虑了这两个系统（ASC-TAC和RTGT）在组织工程以及诸如纤维化、机化、动脉粥样硬化和肿瘤基质等病理过程中的联合作用。
