Miyata T, Oda O, Inagi R, Iida Y, Araki N, Yamada N, Horiuchi S, Taniguchi N, Maeda K, Kinoshita T
Department of Internal Medicine, Branch Hospital, Nagoya University School of Medicine, Japan.
J Clin Invest. 1993 Sep;92(3):1243-52. doi: 10.1172/JCI116696.
beta 2-Microglobulin (beta 2M) is a major constituent of amyloid fibrils in hemodialysis-associated amyloidosis, a complication of long-term hemodialysis patients. Amyloid fibril proteins were isolated from connective tissues forming carpal tunnels in hemodialysis patients with carpal tunnel syndrome. Two-dimensional polyacrylamide gel electrophoresis and Western blotting demonstrated that most of the beta 2M forming amyloid fibrils exhibited a more acidic pI value than normal beta 2M. This acidic beta 2M was also found in a small fraction of beta 2M in sera and urine from these patients, whereas heterogeneity was not observed in healthy individuals. We purified acidic and normal beta 2M from the urine of long-term hemodialysis patients and compared their physicochemical and immunochemical properties. Acidic beta 2M, but not normal beta 2M, was brown in color and fluoresced, both of which are characteristics of advanced glycation end products (AGEs) of the Maillard reaction. Immunochemical studies showed that acidic beta 2M reacted with anti-AGE antibody and also with an antibody against an Amadori product, an early product of the Maillard reaction, but normal beta 2M did not react with either antibody. Incubating normal beta 2M with glucose in vitro resulted in a shift to a more acidic pI, generation of fluorescence, and immunoreactivity to the anti-AGE antibody. The beta 2M forming amyloid fibrils also reacted with anti-AGE antibody. These data provided evidence that AGE-modified beta 2M is a dominant constituent of the amyloid deposits in hemodialysis-associated amyloidosis.
β2微球蛋白（β2M）是血液透析相关淀粉样变性中淀粉样纤维的主要成分，这是长期血液透析患者的一种并发症。从患有腕管综合征的血液透析患者形成腕管的结缔组织中分离出淀粉样纤维蛋白。二维聚丙烯酰胺凝胶电泳和蛋白质印迹法表明，形成淀粉样纤维的大多数β2M的等电点（pI）值比正常β2M更偏酸性。在这些患者的血清和尿液中的一小部分β2M中也发现了这种酸性β2M，而在健康个体中未观察到异质性。我们从长期血液透析患者的尿液中纯化了酸性和正常的β2M，并比较了它们的物理化学和免疫化学性质。酸性β2M呈褐色且发荧光，而正常β2M则没有，这两者都是美拉德反应晚期糖基化终产物（AGEs）的特征。免疫化学研究表明，酸性β2M与抗AGE抗体反应，也与针对美拉德反应早期产物阿马多里产物的抗体反应，但正常β2M与这两种抗体均无反应。在体外将正常β2M与葡萄糖孵育会导致pI值向更酸性转变、产生荧光并对抗AGE抗体产生免疫反应性。形成淀粉样纤维的β2M也与抗AGE抗体反应。这些数据证明，AGE修饰的β2M是血液透析相关淀粉样变性中淀粉样沉积物的主要成分。
