Akiyama M, Dale B A, Sun T T, Holbrook K A
Department of Biological Structure, University of Washington School of Medicine, Seattle, USA.
J Invest Dermatol. 1995 Dec;105(6):844-50. doi: 10.1111/1523-1747.ep12326649.
It has been suggested that the bulge of the hair follicle contains a pool of follicular stem cells that may serve as a target site of graft-versus-host disease and as a source of cells with carcinogenic potential. The bulge is prominent in the developing follicle although it is a subtle swelling in the adult follicle. In this paper, we studied the bulge in human fetal skin specimens. Ultrastructurally, the bulge cells, especially the interior cells, have abundant free ribosomes and glycogen particles, but almost no cytoplasmic organelles indicative of differentiation. Immunostaining with several specific anti-keratin antibodies demonstrated that the bulge cells express keratins of both stratified and simple epithelia. Melanocytes and Merkel cells, defined by immunohistochemical and ultrastructural criteria, are seen among bulge cells. Laser confocal microscopy revealed that primitive smooth muscle cells attached directly to the bulge initially at the mid-bulbous hair peg, the stage when the bulge is most prominent. K-laminin and type VII collagen are strongly expressed in the dermoepidermal junction of the bulge and between the matrix area of the bulb and the dermal papilla. Thus, the bulge of human hair follicle is not only an attachment site for arrector pili muscle, but also a pool of keratinocytes that are relatively undifferentiated.
有人提出，毛囊的隆突部含有一群毛囊干细胞，它们可能是移植物抗宿主病的靶位点，也是具有致癌潜能细胞的来源。隆突部在发育中的毛囊中很明显，尽管在成人毛囊中它只是一个细微的肿胀。在本文中，我们研究了人类胎儿皮肤标本中的隆突部。在超微结构上，隆突部细胞，尤其是内部细胞，有丰富的游离核糖体和糖原颗粒，但几乎没有表明分化的细胞质细胞器。用几种特异性抗角蛋白抗体进行免疫染色表明，隆突部细胞表达复层和单层上皮的角蛋白。根据免疫组织化学和超微结构标准确定的黑素细胞和默克尔细胞可见于隆突部细胞之间。激光共聚焦显微镜显示，原始平滑肌细胞最初在球茎中部毛栓处直接附着于隆突部，此时隆突部最为明显。K-层粘连蛋白和VII型胶原在隆突部的真皮表皮交界处以及球茎基质区和真皮乳头之间强烈表达。因此，人类毛囊的隆突部不仅是立毛肌的附着位点，也是相对未分化的角质形成细胞池。
