Department of Neurology, Fukushima Medical University, 1, Hikarigaoka, Fukushima 960-1295, Japan.
BMC Neurol. 2012 Apr 27;12:22. doi: 10.1186/1471-2377-12-22.
Distal myopathy with rimmed vacuoles/hereditary inclusion body myopathy is clinically characterized by the early involvement of distal leg muscles. The striking pathological features of the myopathy are muscle fibers with rimmed vacuoles. To date, the role of aquaporin-4 water channel in distal myopathy with rimmed vacuoles/hereditary inclusion body myopathy has not been studied.
Here, we studied the expression of aquaporin-4 in muscle fibers of a patient with distal myopathy with rimmed vacuoles/hereditary inclusion body myopathy. Immunohistochemical and immunofluorescence analyses showed that sarcolemmal aquaporin-4 immunoreactivity was reduced in many muscle fibers of the patient. However, the intensity of aquaporin-4 staining was markedly increased at rimmed vacuoles or its surrounding areas and in some muscle fibers. The fast-twitch type 2 fibers were predominantly involved with the strong aquaporin-4-positive rimmed vacuoles and TAR-DNA-binding protein-43 aggregations. Rimmed vacuoles with strong aquaporin-4 expression seen in the distal myopathy with rimmed vacuoles/hereditary inclusion body myopathy patient were not found in control muscles without evidence of neuromuscular disorders and the other disease-controls.
Aquaporin-4 might be crucial in determining the survival or degeneration of fast-twitch type 2 fibers in distal myopathy with rimmed vacuoles/hereditary inclusion body myopathy.
边缘空泡性肌病/遗传性包涵体肌病的临床表现为下肢远端肌肉的早期受累。该病的显著病理特征是肌纤维有空泡形成。迄今为止，水通道蛋白-4 在边缘空泡性肌病/遗传性包涵体肌病中的作用尚未被研究。
在这里，我们研究了边缘空泡性肌病/遗传性包涵体肌病患者肌纤维中 aquaporin-4 的表达。免疫组化和免疫荧光分析显示，患者的许多肌纤维中细胞膜 aquaporin-4 免疫反应性降低。然而，在边缘空泡或其周围区域以及一些肌纤维中，aquaporin-4 染色强度明显增加。快肌纤维 2 型主要受累，伴有强阳性 aquaporin-4 边缘空泡和 TAR-DNA 结合蛋白-43 聚集。在边缘空泡性肌病/遗传性包涵体肌病患者的远端肌纤维中观察到的强阳性 aquaporin-4 表达的边缘空泡，在无神经肌肉疾病和其他疾病对照的正常肌肉中并未发现。
aquaporin-4 可能在决定边缘空泡性肌病/遗传性包涵体肌病中快肌纤维 2 型的存活或退化中起关键作用。
