Hamada Y, Nakamura J, Naruse K, Komori T, Kato K, Kasuya Y, Nagai R, Horiuchi S, Hotta N
Third Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Diabetes Care. 2000 Oct;23(10):1539-44. doi: 10.2337/diacare.23.10.1539.
To clarify the role of the polyol pathway in the intracellular formation of advanced glycation end products in human tissues, we examined the effects of epalrestat, an aldose reductase inhibitor, on the level of Nepsilon-(carboxymethyl)lysine (CML) along with 3-deoxyglucosone (3-DG) and triosephosphates in erythrocytes from diabetic patients. Plasma thiobarbituric acid-reactive substances (TBARS) were also determined as indicators of oxidative stress.
Blood samples were collected from 12 nondiabetic volunteers, 38 untreated type 2 diabetic patients, and 16 type 2 diabetic patients who had been treated with 150 mg epalrestat/day. Blood samples were also collected from 14 of the untreated type 2 diabetic patients before and after the administration of epalrestat for 2 months. The amount of erythrocyte CML was determined by a competitive enzyme-linked immunosorbent assay, and 3-DG was measured by high-performance liquid chromatography
In diabetic patients not treated with epalrestat, the erythrocyte CML level was significantly elevated above levels seen in nondiabetic individuals (49.9 +/- 5.0 vs. 31.0 +/- 5.2 U/g protein, P < 0.05) and was significantly lower in patients receiving epalrestat (33.1 +/- 3.8 U/g protein, P < 0.05). Similar results were observed with 3-DG. The treatment of patients with epalrestat for 2 months significantly lowered the level of erythrocyte CML (46.2 +/- 5.6 at baseline vs. 34.4 +/- 5.0 U/g protein, P < 0.01) along with erythrocyte 3-DG (P < 0.05), triosephosphates (P < 0.05), fructose (P < 0.05), sorbitol (P < 0.05), and plasma TBARS (P < 0.05) without changes in plasma glucose and HbA(1c) levels. A positive correlation was evident between the erythrocyte CML and sorbitol (r = 0.49, P < 0.01) or fructose (r = 0.40, P < 0.05) levels in diabetic patients.
The results indicate that epalrestat administration lowers CML and associated variables and that polyol metabolites are correlated with CML in the erythrocytes of diabetic patients. The observed results suggest that aldose reductase activity may play a substantial role in the intracellular formation of CML in the mediation of reactive intermediate metabolites and oxidative stress.
为阐明多元醇途径在人体组织中晚期糖基化终产物细胞内形成过程中的作用，我们研究了醛糖还原酶抑制剂依帕司他对糖尿病患者红细胞中Nε-（羧甲基）赖氨酸（CML）水平以及3-脱氧葡萄糖酮（3-DG）和磷酸丙糖的影响。血浆硫代巴比妥酸反应性物质（TBARS）也作为氧化应激指标进行了测定。
采集了12名非糖尿病志愿者、38名未经治疗的2型糖尿病患者以及16名接受每日150 mg依帕司他治疗的2型糖尿病患者的血样。还采集了14名未经治疗的2型糖尿病患者在服用依帕司他2个月前后的血样。通过竞争性酶联免疫吸附测定法测定红细胞CML含量，用高效液相色谱法测定3-DG含量。
未接受依帕司他治疗的糖尿病患者红细胞CML水平显著高于非糖尿病个体（49.9±5.0 vs. 31.0±5.2 U/g蛋白质，P<0.05），而接受依帕司他治疗的患者红细胞CML水平显著降低（33.1±3.8 U/g蛋白质，P<0.05）。3-DG也观察到类似结果。依帕司他治疗患者2个月后，红细胞CML水平（基线时为46.2±5.6 vs. 34.4±5.0 U/g蛋白质，P<0.01）、红细胞3-DG（P<0.05）、磷酸丙糖（P<0.05）、果糖（P<0.05）、山梨醇（P<0.05）和血浆TBARS（P<0.05）均显著降低，而血浆葡萄糖和糖化血红蛋白（HbA1c）水平无变化。糖尿病患者红细胞CML与山梨醇（r = 0.49，P<0.01）或果糖（r = 补0.40，P<0.05）水平之间存在明显正相关。
结果表明，服用依帕司他可降低CML及相关变量，且多元醇代谢产物与糖尿病患者红细胞中的CML相关。观察结果提示，醛糖还原酶活性可能在活性中间代谢产物和氧化应激介导的细胞内CML形成中起重要作用。
