MacPherson B R, Leslie K O, Lizaso K V, Schwarz J E
Department of Pathology, University of Vermont, Burlington 05405.
Hum Pathol. 1993 Jul;24(7):710-6. doi: 10.1016/0046-8177(93)90006-3.
Mesangial cells of the renal glomerulus are thought to have contractile properties, resembling those of smooth muscle cells. Since actin synthesis in mesangial cells is increased in selected animal models of glomerulonephritis, we evaluated the expression of alpha-smooth muscle actin (ASMA), the principal actin isoform found in smooth muscle cells, in biopsy specimens from patients with primary glomerular disorders and in control tissues. Normal glomeruli and glomeruli in acute tubulointerstitial disorders showed few or no ASMA-positive cells in the glomeruli. In contrast, ASMA expression in mesangial cells was increased in minimal change disease, focal segmental glomerulosclerosis, mesangial proliferative glomerulonephritis, membranous glomerulonephritis, and immunoglobulin A nephropathy. In membranoproliferative glomerulonephritis and cryoglobulinemic glomerulonephritis both mesangial and capillary loop ASMA-positive cells were observed with a segmental distribution. In addition, ASMA-positive interstitial cells were seen in many biopsy specimens and often were increased in number in biopsy specimens showing early interstitial fibrosis and tubular atrophy. We conclude that ASMA synthesis in mesangial cells is upregulated in a variety of glomerular disorders, frequently associated with increased cell proliferation and mesangial matrix production. This phenotypic change may be an indicator of mesangial cell activation after injury and may have important pathophysiologic consequences.
肾小球系膜细胞被认为具有收缩特性，类似于平滑肌细胞。由于在某些肾小球肾炎动物模型中，系膜细胞中的肌动蛋白合成增加，我们评估了α-平滑肌肌动蛋白（ASMA）的表达，ASMA是平滑肌细胞中主要的肌动蛋白异构体，在原发性肾小球疾病患者的活检标本和对照组织中进行评估。正常肾小球以及急性肾小管间质性疾病中的肾小球在肾小球中显示很少或没有ASMA阳性细胞。相比之下，在微小病变肾病、局灶节段性肾小球硬化、系膜增生性肾小球肾炎、膜性肾小球肾炎和免疫球蛋白A肾病中，系膜细胞中的ASMA表达增加。在膜增生性肾小球肾炎和冷球蛋白血症性肾小球肾炎中，观察到系膜和毛细血管袢ASMA阳性细胞呈节段性分布。此外，在许多活检标本中可见ASMA阳性间质细胞，并且在显示早期间质纤维化和肾小管萎缩的活检标本中其数量通常增加。我们得出结论，在各种肾小球疾病中，系膜细胞中的ASMA合成上调，这通常与细胞增殖增加和系膜基质产生有关。这种表型变化可能是损伤后系膜细胞活化的指标，并且可能具有重要的病理生理后果。
