| Background and objectives: Diabetic retinopathy(DR), a microvascular complication of diabetes, is one of the major causes of blindness in patients with diabetes mellitus. Currently, the pathogenesis of DR has not been clarified. Studies suggested that the levels of homocysteine(Hcy) were higher in patients with DR compared the patients without, although the results were controversial. Furthermore, several studies showed that the folic acid and vitamin B12 deficiency could increase the levels of Hcy, but these results were also conflicted. The objectives of this study were to(1) examine the associations of Hcy levels with DR, folic acid and vitamin B12 levels, and(2) evaluate the effects of folic acid and vitamin B12 on the progression of DR, Hcy levels, and the outcomes in patients with DR.Methods:1 Sixty patients(males: 33, females: 27) with type 2 diabetes mellitus aged 25-75 years(mean±SD: 55.24±11.84 years) from the endocrinology department of Chengde Central Hospital between December 2013 and May 2014 were included. Of these, 30 were diabetes mellitus patients without retinopathy(NDR group), and 30 with diabetic retinopathy(DR group). Another thirty health subjects aged 31-72 years(55.10±12.08 years, males, 14, females, 16) were included as controls. We measured and compared the levels of fasting plasma glucose(FBG), triglyceride(TG), cholesterol(CHO), glycosylated hemoglobin(Hb Al C), 24 hours urine albumin excretion rate(UAER), Hcy, folic acid and vitamin B12 among these subjects.2 Additional included sixty DR patients(males: 38, females: 22) aged 35-65 years(mean±SD: 50.55±8.54 years) from the endocrinology department of Chengde Central Hospital between December 2013 and May 2014 were randomly assigned(1:1) to receive either pancreatic kininogenase 120 U three times a day(controls) or folic acid 5 mg three times a day, plus vitamin B12 0.5 mg three times a day, plus pancreatic kininogenase 120 U three times a day(study group) for 7 days. Each group were tested the best corrected visual acuity, funduscopy and retinal angiography, and measured the levels of Hcy, folic acid and vitamin B12.Results:1 There were no statistically significant differences in mean age, duration of disease, levels of TG and CHO among control group, NDR group and DR group(P > 0.05). The levels of FBG, Hb A1 C, UAER and MCV were significant higher in NDR and DR group compared with controls(P<0.05), whereas the levels of RBC, TBIL and DBIL in DR and NDR groups were significant lower(P<0.05). Subgroup analysis suggested that the levels of FBG, Hb A1 C and UAER in DR group were higher than NDR group, but the TBIL and DBIL levels were lower, the differences were statistically significant(P<0.05). A significant higher levels of Hcy were observed in DM patients(NDR and DR group) compared with controls(s14.83±2.78, 6.32±9.61 and 11.62±2.83μmol/L, respectively), but the folic acid(4.89±2.15, 4.46±2.07 and 6.12±2.35μg/L, respectively) and vitamin B12 levels(397.2±142.9, 315.6±137.2 and 425.8±189.3 ng/L, respectively) in DM patients were statistical fewer than in controls(P<0.05). Non-conditional logistic regression suggested that the duration of disease, Hb A1 C, Hcy and CHO were independent risk factors of DR, with OR and 95% confidence interval(CI) of 2.525(1.890-2.662), 1.884(1.423-2.374), 1.220(0.916-1.466) and 1.476(1.102-1.868), respectively.2 The levels of Hcy( pre-treatment vs post-treatment in controls: 23.32±8.44 vs 18.91±4.64μmol/L, pre-treatment vs post-treatment in study group: 27.14±7.60 vs 11.30±3.19μmol/L) reduced significantly, and folic acid( pre-treatment vs post-treatment in controls: 5.00±2.98 vs 10.94±6.59μg/L, pre-treatment vs post-treatment in study group: 4.68±2.44 vs 16.93±3.56μg/L) and vitamin B12 levels( pre-treatment vs post-treatment in controls: 346.03±130.68 vs 508.85±114.22ng/L, pre-treatment vs post-treatment in study group: 355.6±98.60 vs 600.46±98.76ng/L) increased significantly after 6 months of treatment in both groups. Compared with controls, the Hcy levels in study group decreased more( study group vs controls: 11.30±3.19 vs 18.91±4.64μmol/L), and the folic acid( study group vs controls: 16.93±3.56 vs 10.94±6.59μg/L) and vitamin B12( study group vs controls: 600.46±98.76 vs 508.85±114.22ng/L) levels increased more, all the differences were significant(P<0.05), although both groups had changed significantly compared with that before treatment. The best corrected visual acuity( pre-treatment vs post-treatment in controls: 0.59±0.11 vs 0.68±0.13, pre-treatment vs post-treatment in study group: 0.57±0.13 vs 0.79±0.12) and fundus scores( pre-treatment vs post-treatment in controls: 7.65±0.85 vs 6.42±0.98, pre-treatment vs post-treatment in study group: 7.58±0.88 vs 4.16±1.16) improved significantly in both groups, but the study group improved more than controls. The total effective rates in study group and controls were 86.8% and 65.0%, respectively(χ2=69.214, P<0.05).Conclusions: Hcy is one of the independent risk factors of DR. The addition of folic acid and vitamin B12 could decrease the Hcy levels, and improve the outcomes in patients with DR. |
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