Relationship between plasma level of homocysteine and urine microalbumin in incipient type 2 diabetic nephropathy

Objective To investigate the relationship between plasma level of homocysteine(Hcy)and urine microalbumin (MAlb) in incipient type 2 diabetic (T2DM) nephropathy,and its relevant factors. Methods Two hundred and fifty-two cases of T2DM and 30 cases of normal control were enrolled in the study. Cases of T2DM were divided into two groups, one with incipient diabetic nephropathy and another without renal complication (NDC). Plasma levels of Hcy, folate (FA), vitamin B_ 12 (VitB_ 12 ), glycosylated hemoglobin A1c (HbA1c), and fasting blood glucose (FBG), postprandial blood glucose (PBG), blood levels of creatinine (Cr), cholesterol, triglyceride, transforming growth factor β_1, urine levels of N-acetylglucosaminidase (NAG), MAlb and ratio of MAlb/Cr were measured for all the subjects. Mutation of the C677T transition of methylenetetrahydrofolate reductase (MTHFR) gene was determined by polymerase chain reaction-restriction fragment length polymorphism. Results Plasma level of Hcy was (16.6±12.6) μmol/L in patients with incipient type 2 diabetic nephropathy, significantly higher than that in normal control group(9.7±2.0)μmol/L, P0.05, and that was(16.6±12.6) μmol/L in patients with incipient type 2 diabetic nephropathy, also significantly higher than that in those without renal complication(11.9±7.3)μmol/L, P0.05. Occurrence of incipient diabetic nephropathy was significantly higher in those with hyperhomocysteinmia than those with normal plasma level of Hcy (61.4% vs 36.1%, P0.05). Plasma level of Hcy in T2DM patients was positively related to the TT genetype of MTHFR, body mass index, FBG, PBG, HbA1c, NAG, MAlb/Cr, course of disease, smoking and metformin treatment, and were negatively related to plasma levels of FA and VitB_ 12 . Multivariate logistic regression analysis showed that course of disease, diastolic blood pressure, FBG, NAG and plasma level of Hcy all were independent risk factors for incipient diabetic nephropathy. Conclusions Higher plasma level of Hcy was an independent risk factor for incipient diabetic nephropathy. The TT genetype of MTHFR, plasma levels of FA, Vit B_ 12 , MA1b/Cr, urine level of NAG and metabolic disorder all influenced plasma level of Hcy in T2DM.