Nakajima N, Nagahiro S, Sano T, Satomi J, Satoh K
Department of Neurological Surgery, School of Medicine, The University of Tokushima, Japan.
Acta Neuropathol. 2000 Nov;100(5):475-80. doi: 10.1007/s004010000220.
We used immunohistochemical methods to analyze the phenotypes of smooth muscle cells (SMCs) in human cerebral arteries and aneurysmal walls. Thirty-two aneurysmal walls were studied; 31 aneurysmal walls were resected at operation and 1 aneurysm was obtained at autopsy. Seven control arteries were obtained at autopsy. Semiserial sections were subjected to immunohistochemical staining with antibodies to alpha-smooth muscle actin (alpha-SMA), desmin and smooth muscle myosin heavy chain isoforms: SM1, SM2 and SMemb. In control cerebral arteries, SMCs in the media were strongly immunostained for alpha-SMA, desmin, SM1 and SM2; immunoreactivity for SMemb was faint or weakly positive. SMCs in both non-ruptured and ruptured aneurysmal walls showed no staining for desmin; the expression of alpha-SMA was well preserved. Compared with control cerebral arteries, in 4 of 11 non-ruptured aneurysmal walls, the staining intensity of SMCs for SMemb was clearly increased. In ruptured aneurysmal walls, the expression of SM2 was lower than in control cerebral arteries and non-ruptured aneurysmal walls. Our study suggests that the phenotype of SMCs in aneurysmal walls is different from the contractile type in the media of normal cerebral arteries, at least partially changing to the synthetic type in some non-ruptured aneurysms. SMCs in ruptured aneurysmal walls may have lost both phenotypes before rupture. Phenotypic modulation of SMCs in the aneurysmal walls appears to be related to a remodeling of the aneurysmal wall and to a rupture mechanism.
我们采用免疫组化方法分析人脑动脉和动脉瘤壁中平滑肌细胞（SMC）的表型。研究了32个动脉瘤壁；31个动脉瘤壁在手术中切除，1个动脉瘤在尸检时获得。7条对照动脉在尸检时获取。对连续半薄切片进行免疫组化染色，使用抗α平滑肌肌动蛋白（α-SMA）、结蛋白和平滑肌肌球蛋白重链亚型：SM1、SM2和SMemb的抗体。在对照脑动脉中，中膜的SMC对α-SMA、结蛋白、SM1和SM2呈强免疫染色；对SMemb的免疫反应性微弱或弱阳性。未破裂和破裂动脉瘤壁中的SMC对结蛋白均无染色；α-SMA的表达保存良好。与对照脑动脉相比，11个未破裂动脉瘤壁中有4个，SMC对SMemb的染色强度明显增加。在破裂的动脉瘤壁中，SM2的表达低于对照脑动脉和未破裂的动脉瘤壁。我们的研究表明，动脉瘤壁中SMC的表型不同于正常脑动脉中膜的收缩型，至少在一些未破裂的动脉瘤中部分转变为合成型。破裂动脉瘤壁中的SMC在破裂前可能已失去两种表型。动脉瘤壁中SMC的表型调节似乎与动脉瘤壁的重塑和破裂机制有关。
