Diabetic Retinopathy - Treatment

Vitamin E - updated: 15 March 2008

High-dose vitamin E supplementation normalizes retinal blood flow and creatinine clearance in patients with type 1 diabetes

Diabetes Care. 1999 Aug;22(8):1245-51

Bursell SE, Clermont AC, Aiello LP, Aiello LM, Schlossman DK, Feener EP, Laffel L, King GL.

OBJECTIVE: To determine the effectiveness of vitamin E treatment in normalizing retinal blood flow and renal function in patients with <10 years of type 1 diabetes. RESEARCH DESIGN AND METHODS: An 8-month randomized double-masked placebo-controlled crossover trial evaluated 36 type 1 diabetic and 9 nondiabetic subjects. Subjects were randomly assigned to either 1,800 IU vitamin E/day or placebo for 4 months and followed, after treatment crossover, for a further 4 months. Retinal blood flow was measured using video fluorescein angiography, and renal function was assessed using normalized creatinine clearance from timed urine collections. RESULTS: After vitamin E treatment, serum levels of vitamin E were significantly elevated (P<0.01) in both type 1 diabetic and control patients. Hemoglobin A1c was not affected by vitamin E treatment. Diabetic patient baseline retinal blood flow (29.1+/-7.5 pixel2/s) was significantly (P = 0.030) decreased compared with that of nondiabetic subjects (35.2+/-7.2 pixel2/s). After vitamin E treatment, diabetic patient retinal blood flow (34.5+/-7.8 pixel2/s) was significantly increased (P<0.001) and was comparable with that of nondiabetic subjects. Additionally, vitamin E treatment significantly (P = 0.039) normalized elevated baseline creatinine clearance in diabetic patients. CONCLUSIONS: Oral vitamin E treatment appears to be effective in normalizing retinal hemodynamic abnormalities and improving renal function in type 1 diabetic patients of short disease duration without inducing a significant change in glycemic control. This suggests that vitamin E supplementation may provide an additional benefit in reducing the risks for developing diabetic retinopathy or nephropathy.

Effect of modest vitamin E supplementation on blood glycated hemoglobin and triglyceride levels and red cell indices in type I diabetic patients

J Am Coll Nutr. 1996 Oct;15(5):458-61

Jain SK, McVie R, Jaramillo JJ, Palmer M, Smith T.

OBJECTIVE: The glycation of proteins and elevated triglyceride (TG) levels are two of the major risk factors in the development of complications of diabetes. Previous studies have found some beneficial effects of supplementation of pharmacological doses (900-2000 IU/day) of vitamin E in Type II diabetic patients. This study examined whether supplementation with a modest dose of vitamin E (100 IU/day) had any effect on blood glucose, glycated hemoglobin (GHb), TG or red cell counts in Type I diabetic patients. METHODS: 35 diabetic patients were supplemented with either DL-alpha-tocopherol (vitamin E) capsules (orally, 100 IU/day) or a placebo for 3 months in a double-blind clinical trial. Fasting blood was collected from each diabetic patient before and after vitamin E or placebo supplementation. Data were analyzed using paired "t" tests and the Wilcoxon Signed Rank Test. RESULTS: Levels of GHb (mean +/- SEM) were 11.5 +/- 0.4 and 12.8 +/- 0.9% (p < 0.05); glucose, 8.8 +/- 1.2 and 11.6 +/- 1.3 mM; and TG, 2.2 +/- 0.2 and 2.9 +/- 0.3 mM (p < 0.03) after vitamin E supplementation versus before supplementation. There were no differences in these parameters after supplementation with the placebo. There was no effect on blood RBC, hematocrit, and hemoglobin levels after supplementation of vitamin E or the placebo. There were no differences in ages and duration of diabetes between placebo and vitamin E-supplemented groups. CONCLUSIONS: This study suggests that modest vitamin E supplementation (100 IU/day) can significantly lower blood GHb and TG levels and does not have any effect on red cell indices in Type I diabetic patients.

Publication Types:

• Placebo controlled

Vitamin E prevents diabetes-induced abnormal retinal blood flow via the diacylglycerol-protein kinase C pa

Am J Physiol. 1995 Aug;269(2 Pt 1):E239-46

Kunisaki M, Bursell SE, Clermont AC, Ishii H, Ballas LM, Jirousek MR, Umeda F, Nawata H, King GL.

We have characterized effects of d-alpha-tocopherol (vitamin E) on activation of protein kinase C (PKC) and diacylglycerol (DAG) levels in retinal tissues of diabetic rats and correlated its effects to diabetes-induced changes in retinal hemodynamics. Membrane PKC specific activities were increased by 71% in streptozocin-induced diabetic rats compared with controls (P < 0.05). Western blot analysis showed that membrane PKC-beta II was increased by 133 +/- 5% (P < 0.05). Injection of d-alpha-tocopherol (40 mg/kg ip) every other day prevented the increases in membrane PKC specific activity and PKC-beta II protein by immunoblots. Diabetes-induced increases in DAG levels were also normalized by d-alpha-tocopherol treatment of 2 wk duration. Physiologically, angiographic abnormalities of retinal hemodynamics based on computerized video-based fluorescein angiography and associated with increases of DAG and membranous PKC levels were also prevented by d-alpha-tocopherol treatment in diabetic rats. The effect of d-alpha-tocopherol on retinal vascular cells was also studied. Exposure of retinal endothelial cells to 22 mM glucose for 3 days increased total DAG and [3H]palmitate-labeled DAG levels by 35 +/- 8 and 50 +/- 8% (P < 0.05), respectively, compared with exposure to 5.5 mM glucose. The presence of d-alpha-tocopherol (50 micrograms/ml) prevented the increases in total DAG and [3H]palmitate-labeled DAG levels in cells exposed to 22 mM glucose. These findings suggested that treatment with d-alpha-tocopherol can prevent diabetes-induced abnormalities in rat retinal blood flow.(

Publication Types:

• Animal Study

Publication Types:

• Review