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


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.
Bursell
S E
SE
Beetham Eye Institute, Joslin Diabetes Center, Boston, Massachusetts, USA.
Clermont
A C
AC
Aiello
L P
LP
Aiello
L M
LM
Schlossman
D K
DK
Feener
E P
EP
Laffel
L
L
King
G L
GL
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D003404:Creatinine / Q000378:metabolism*; D018592:Cross-Over Studies; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy* / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000188:drug therapy / Q000378:metabolism; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood; D012039:Regional Blood Flow / Q000187:drug effects; D012171:Retinal Vessels / Q000187:drug effects*; D016896:Treatment Outcome; D014810:Vitamin E / Q000009:adverse effects / Q000627:therapeutic use*
D017395:Plasminogen Activator Inhibitor 1; D014810:Vitamin E; D003404:Creatinine