线粒体脑肌病的血管神经病变机制

Vasculopathy in the Pathogenesis of Mitochondrial Encephalomyopathies

目的探讨血管病变和组织缺血在线粒体脑肌病发病机制中的作用。 方法采用CT灌注成像技术对发病期线粒体脑肌病的脑组织灌注状况进行评估，通过病理学方法观察肌肉组织血管的线粒体结构改变。 结果7例不同类型的线粒体脑肌病患者发病期主要临床表现为卒中样发作和疴陛发作，病变多累及单侧或双侧的顶颞枕叶。病变区域脑血流量和脑血容量降低，对比剂平均通过时间和达峰时间延长。病理学发现：琥珀酸脱氢酶（Succinate Dehydrogenase，SDH）染色血管壁呈不连续或浓重深染色，血管壁平滑肌细胞和内皮细胞线粒体数量显著增多，增大肿胀呈空泡状。 结论线粒体脑肌病是一种系统性血管病，脑组织灌注不足和代谢障碍在发病机制中具有重要的作用。

Objective To explore the role of vasculopathy and ischemic events in the pathomechanism of mitochondrial encephalomyopathies. Methods Computed tomography perfusion imaging has been applied to the evaluation of brain perfusion during the symptomatic period of mitochondrial encephalomyopathies, and mitochondria structures of the blood vessels wall within muscle fibers were observed by pathological technique. Results 7 cases of different clinical types of mitochondrial encephalomyopathies were characterized by recurrent stroke-like episodes and seizures. Neuroimaging studies demonstrated uni- and bilateral lesions predominantly in the occipital and temporal-parietal lobes, in which areas cerebral blood flow and cerebral blood volume decreased, mean transit time and the time to peak were delayed on computed tomography perfusion imaging. Muscle pathology showed incontinuous or dark staining on vessel wall by succinic acid dehydrogenase staining. Electron microscopy of blood vessels has shown swelling and a striking increase in the number of mitochondria in the smooth muscle and endothelial cells. Conclusion Mitochondrial encephalomyopathies is a systemic vascular disease. Cerebral hypoperfusion and metabolic dysfunction may represent an important feature of the pathogenesis of the strokelike episodes.