Department of Pathology, Osaka Police Hospital, Osaka, Japan.
Department of Neurology, National Hospital Organization Toneyama National Hospital, Toyonaka, Japan.
Neuropathology. 2019 Oct;39(5):404-410. doi: 10.1111/neup.12593. Epub 2019 Aug 13.
We investigated two autopsy cases of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) using immunohistochemical staining with an anti-mitochondrial antibody against translocase of the outer membrane 20 (TOMM20). In case 1, the patient was a 42-year-old man with a disease duration of 53 days, and in case 2, the patient was a 62-year-old woman with a disease duration of 27 months. In both the cases autopsy revealed moderate atrophy of the cerebrum and cerebellum and multifocal necrotizing lesions, irrespective of the vascular territory. Case 1 showed multiple areas with total necrosis in the cortex, accompanied by increases in number of protoplasmic astrocytes and acidophilic neurons as well as axonal swelling, suggestive of acute or subacute stage stroke-like lesions (SLLs). In case 2, most of the SLLs displayed laminar spongy change in a rarefied cortex, and were considered to be at the chronic stage. In both the cases, capillary proliferation was noted within the SLLs, particularly in the acute phase. Endothelial cells of proliferating capillaries were strongly positive for TOMM20. In the cortex outside the SLLs, microvessels displayed only a fine granular immunoreactivity, as is seen in the controls. Although smooth muscle cells and endothelial cells in pial arteries and arterioles were also strongly positive for TOMM20, the territories of the affected pial arteries and arterioles did not correlate with the distribution of the SLLs. Although MELAS is characterized by recurrent stroke-like episodes (SLEs), the pathogenetic relationship between SLEs and mitochondrial angiopathy remains unknown. An aberrant increase of mitochondria in the capillary endothelial cells of SLLs may disturb endothelial function, thus playing a role in the formation or development of SLLs.
我们使用针对外膜转位酶 20（TOMM20）的抗线粒体抗体进行了两例线粒体肌病、脑病、乳酸酸中毒和卒中样发作（MELAS）的尸检研究。在病例 1 中，患者为 42 岁男性，病程为 53 天；在病例 2 中，患者为 62 岁女性，病程为 27 个月。在两个病例中，尸检均显示大脑和小脑中度萎缩和多灶性坏死病变，与血管区域无关。病例 1 显示皮质中有多个区域发生全层坏死，伴有数量增加的原生质星形胶质细胞和嗜酸性神经元以及轴突肿胀，提示为急性或亚急性卒中样病变（SLL）期。病例 2 中，大多数 SLL 显示皮质稀疏区呈层状海绵状改变，被认为处于慢性期。在两个病例中，SLL 内均观察到毛细血管增生，特别是在急性期。增生毛细血管内皮细胞 TOMM20 染色阳性。在 SLL 之外的皮质中，微血管仅显示细颗粒免疫反应性，与对照组相同。尽管脑动脉平滑肌细胞和小动脉内皮细胞也对 TOMM20 呈强阳性反应，但受影响的脑动脉和小动脉的区域与 SLL 的分布没有相关性。尽管 MELAS 的特征是复发性卒中样发作（SLE），但 SLE 与线粒体血管病之间的发病机制关系尚不清楚。SLL 毛细血管内皮细胞中线粒体的异常增加可能会干扰内皮功能，从而在 SLL 的形成或发展中发挥作用。
