"PATHOGENIC MECHANISMS AND THERAPUETIC STRATEGIES IN MELAS"

MELAS是一种常见的线粒体疾病，与线粒体DNA的tRNALeu(UUR)基因的m！3243A和GT；G突变有关，以中风、乳酸酸中毒、脑梗塞和水肿为特征。MELAS卒中和水肿的发病机制尚不清楚。如果没有对病理生理学的正确理解，就不可能为这种毁灭性的疾病设计出合理的治疗方法。我们的假设是，皮质血管中的线粒体功能障碍会导致血脑屏障(BBB)的破坏，从而导致中风和相关的水肿。我们已经成功地构建了正常和MELAS血脑屏障的体外工作模型。我们建议在这个模型中研究MELAS中BBB的功能。具体地说，我们将分析调节血脑屏障通透性、水通道和乳酸转运蛋白的紧密连接蛋白，并将我们的结果与呼吸链功能相关联。这些细胞水平的体外研究将扩展到MELAS脑切片，以比较和证实我们在组织水平的发现。 MELAS的治疗管理是坊间传闻，通常无效。我们的体外模型是一个动态系统，可以操作来测试各种血脑屏障保护性药物，这些药物可以恢复屏障功能，因此可以作为中风、乳酸酸中毒和相关水肿的有效治疗剂。我们将使用这个模型来测试类固醇在调节水通道中的作用，以及甘油磷酸肌醇和干扰素-b-1a在调节中风后炎症过程中的作用。 首先，这些研究将对血脑屏障的生理学提供洞察力。其次，它们将揭示由于线粒体功能障碍和能量短缺而导致的MELAS血管通透性的变化。第三，培养模型将使我们能够评估导致渗透性增加的事件的顺序。最后，体外模型提供了一个灵活的系统来测试用于这种毁灭性疾病的药物的治疗价值。

MELAS, a common mitochondrial disease associated with a m!3243A>G mutation in the tRNALeu(UUR) gene of the mitochondrial DNA, is characterized by strokes, lactic acidosis, cerebral infarction and edema. The pathogenesis of strokes and edema in MELAS is not understood. Without a proper understanding of the pathophysiology, it has not been possible to devise rational therapies for this devastating disease. Our hypothesis is that mitochondrial dysfunction in the cortical blood vessels causes a breakdown of the blood-brain barrier (BBB) leading to strokes and associated edema. We have successfully constructed a working in vitro model of a normal and MELAS BBB. We propose to study the function of the BBB in MELAS in this model. Specifically, we will analyze tight junction proteins that regulate BBB permeability, water channels, and lactate transporters and correlate our results with respiratory chain function. These in vitro studies at the cellular level will be extended to MELAS brain sections to compare and confirm our findings at the tissue level. Therapeutic management of MELAS is anecdotal and generally ineffective. Our in vitro model is a dynamic system that can be manipulated to test various BBB protective drugs, which can restore barrier function and thus can be useful therapeutic agents for strokes, lactic acidosis, and associated edema. We will use this model to test the effect of steroids in regulating water channels and of glycerphosphoinositol and interferon-b-1a in modulating the inflammatory process after strokes. First, these studies will provide insight into the physiology of the BBB. Secondly, they will reveal changes in vascular permeability in MELAS due to mitochondrial dysfunction and energy shortage. Third, the culture model will allow us to evaluate the sequence of events leading to the increase in permeability. Finally, the in vitro model provides a flexible system to test the therapeutic value of drugs to be used this devastating illness.