Agardh E, Hultberg B, Agardh C D
Department of Ophthalmology, University Hospital MAS, Malmö, Sweden.
Scand J Clin Lab Invest. 2000 May;60(3):169-74. doi: 10.1080/003655100750044811.
The vascular-injuring amino acid homocysteine was previously shown to be increased in plasma in type 1 diabetic patients with clinical signs of nephropathy. Previous studies have also shown an inconsistent relationship between the development of diabetic nephropathy and retinopathy, indicating different pathogenetic mechanisms. In this study, plasma homocysteine was measured in 25 type 1 diabetic patients with a well-characterized form of severe retinopathy. Furthermore, a group of 24 type 1 diabetic patients with similar age at onset of diabetes and diabetes duration with no or minimal background retinopathy were investigated, in order to determine whether plasma homocysteine levels are different from those in patients with severe retinopathy. Patients with severe retinopathy did not have higher plasma levels of homocysteine (13.9 micromol/L; 5.9-30.7, median and range) than those without retinopathy (10.4 micromol/L; 5.7-18.9). Within the group of patients with severe retinopathy, increased homocysteine levels were confined to the patients (19.9 micromol/L; 10.0-30.7, n=9) with serum creatinine levels > 100 micromol/L, compared to those patients (9.6; 5.9-14.3 micromol/L, n=15) with a serum creatinine below 100 micromol/L. None of the patients without or with minimal background retinopathy had serum creatinine levels > 100 micromol/L. We conclude that diabetic retinopathy is not associated with increased plasma homocysteine levels, but plasma homocysteine accumulates, probably owing to reduced glomerular filtration, in diabetic patients with signs of nephropathy. In these patients, the promoting effect of nephropathy on the development of retinopathy does not seem to be mediated through homocysteine.
先前研究表明，患有肾病临床症状的1型糖尿病患者血浆中损伤血管的氨基酸同型半胱氨酸水平会升高。此前的研究还表明，糖尿病肾病与视网膜病变的发生之间关系并不一致，这表明二者发病机制不同。在本研究中，对25例患有典型严重视网膜病变的1型糖尿病患者的血浆同型半胱氨酸水平进行了检测。此外，还对24例糖尿病发病年龄和病程相近、无或仅有轻微背景性视网膜病变的1型糖尿病患者进行了研究，以确定其血浆同型半胱氨酸水平是否与严重视网膜病变患者不同。严重视网膜病变患者的血浆同型半胱氨酸水平（13.9微摩尔/升；中位数及范围为5.9 - 30.7）并不高于无视网膜病变患者（10.4微摩尔/升；5.7 - 18.9）。在严重视网膜病变患者组中，血清肌酐水平>100微摩尔/升的患者（19.9微摩尔/升；10.0 - 30.7，n = 9）同型半胱氨酸水平升高，而血清肌酐低于100微摩尔/升的患者（9.6；5.9 - 14.3微摩尔/升，n = 15）则不然。无或仅有轻微背景性视网膜病变的患者血清肌酐水平均未>100微摩尔/升。我们得出结论，糖尿病视网膜病变与血浆同型半胱氨酸水平升高无关，但在有肾病迹象的糖尿病患者中，血浆同型半胱氨酸可能由于肾小球滤过率降低而蓄积。在这些患者中，肾病对视网膜病变发展的促进作用似乎并非通过同型半胱氨酸介导。
