Niwa T, Katsuzaki T, Miyazaki S, Miyazaki T, Ishizaki Y, Hayase F, Tatemichi N, Takei Y
Nagoya University, Daiko Medical Center, Japan.
J Clin Invest. 1997 Mar 15;99(6):1272-80. doi: 10.1172/JCI119285.
To investigate the role of the Maillard reaction in the pathogenesis of diabetic complications, we produced several clones of monoclonal antibodies against advanced glycation end products (AGEs) by immunizing mice with AGE-modified keyhole limpet hemocyanin, and found that one clone (AG-1) of the anti-AGE antibodies reacted specifically with imidazolones A and B, novel AGEs. Thus, the imidazolones, which are the reaction products of the guanidino group of arginine with 3-deoxyglucosone (3-DG), a reactive intermediate of the Maillard reaction, were found to be common epitopes of AGE-modified proteins produced in vitro. We determined the erythrocyte levels of imidazolone in diabetic patients using ELISA with the monoclonal anti-imidazolone antibody. The imidazolone levels in the erythrocytes of diabetic patients were found to be significantly increased as compared with those of healthy subjects. Then we studied the localization of imidazolone in the kidneys and aortas obtained from diabetic patients by immunohistochemistry using the antibody. Specific imidazolone immunoreactivity was detected in nodular lesions and expanded mesangial matrix of glomeruli, and renal arteries in an advanced stage of diabetic nephropathy, as well as in atherosclerotic lesions of aortas. This study first demonstrates the localization of imidazolone in the characteristic lesions of diabetic nephropathy and atherosclerosis. These results, taken together with a recent demonstration of increased serum 3-DG levels in diabetes, strongly suggest that imidazolone produced by 3-DG may contribute to the progression of long-term diabetic complications such as nephropathy and atherosclerosis.
为了研究美拉德反应在糖尿病并发症发病机制中的作用，我们用糖基化终末产物（AGEs）修饰的钥孔戚血蓝蛋白免疫小鼠，制备了几种抗晚期糖基化终末产物的单克隆抗体克隆，并发现其中一个抗AGE抗体克隆（AG-1）与咪唑啉A和B（新型AGEs）发生特异性反应。因此，咪唑啉是精氨酸胍基与美拉德反应的活性中间体3-脱氧葡萄糖酮（3-DG）的反应产物，被发现是体外产生的AGE修饰蛋白的共同表位。我们使用单克隆抗咪唑啉抗体的酶联免疫吸附测定法（ELISA）测定糖尿病患者红细胞中咪唑啉的水平。结果发现，糖尿病患者红细胞中的咪唑啉水平与健康受试者相比显著升高。然后，我们使用该抗体通过免疫组织化学研究了糖尿病患者肾脏和主动脉中咪唑啉的定位。在糖尿病肾病晚期的肾小球结节性病变、系膜基质扩张以及肾动脉中，以及主动脉的动脉粥样硬化病变中均检测到特异性咪唑啉免疫反应性。本研究首次证明了咪唑啉在糖尿病肾病和动脉粥样硬化特征性病变中的定位。这些结果，再加上最近证明糖尿病患者血清3-DG水平升高，强烈表明3-DG产生的咪唑啉可能促成肾病和动脉粥样硬化等长期糖尿病并发症的进展。
