Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, Cape Town, South Africa.
Hair and Skin Research Laboratory, Groote Schuur Hospital, Cape Town, South Africa.
Stem Cell Rev Rep. 2020 Dec;16(6):1105-1120. doi: 10.1007/s12015-020-09985-6.
The Primary Scarring Alopecias are characterised by the irreversible destruction and fibrosis of hair follicles, leading to permanent and often disfiguring loss of hair. The pathophysiology of these diseases is not well understood. However, follicular-fibrosis and loss of the stem-cell niche appears to be a common theme. This review explores the pathogenesis of primary scarring alopecias, asking what happens to the stem cells of the hair follicle and how they may contribute to the progression of these diseases. Bulge-resident cells are lost (leading to loss of capacity for hair growth) from the follicle either by inflammatory-mediate apoptosis or through epigenetic reprogramming to assume a mesenchymal-like identity. What proportion of bulge cells is lost to which process is unknown and probably differs depending on the individual PCA and its specific inflammatory cell infiltrate. The formation of fibroblast-like cells from follicular stem cells may also mean that the cells of the bulge have a direct role in the pathogenesis. The identification of specific cells involved in the pathogenesis of these diseases could provide unique diagnostic and therapeutic opportunities to prevent disease progression by preventing EMT and specific pro-fibrotic signals.
原发性瘢痕性脱发的特征是毛囊的不可逆破坏和纤维化，导致永久性且常常是毁容性的脱发。这些疾病的病理生理学尚不清楚。然而，毛囊纤维化和干细胞龛的丧失似乎是一个共同的主题。本综述探讨了原发性瘢痕性脱发的发病机制，探讨了毛囊干细胞发生了什么变化，以及它们如何可能导致这些疾病的进展。滤泡中的隆起细胞通过炎症介导的细胞凋亡或通过表观遗传重编程而丧失（导致毛发生长能力丧失），以获得间充质样特征。隆起细胞中有多少比例的细胞通过哪种途径丢失尚不清楚，而且可能因个体 PCA 及其特定的炎症细胞浸润而异。从毛囊干细胞中形成成纤维细胞样细胞也可能意味着隆起细胞中的细胞在发病机制中具有直接作用。鉴定这些疾病发病机制中涉及的特定细胞可能为通过防止 EMT 和特定的促纤维化信号来预防疾病进展提供独特的诊断和治疗机会。
