Elevated vitreous nitric oxide levels in patients with proliferative diabetic retinopathy

PURPOSE: The aim of this study was to determine nitric oxide levels in the vitreous of patients with proliferative diabetic retinopathy, METHODS: Using the spectrophotometric method based on Griess reaction, we m easured levels of nitrite, the stable product of nitric oxide, in the vitre ous of 21 eyes of 21 patients who underwent vitrectomy for the treatment of proliferative diabetic retinopathy with tractional retinal detachment, pro spectively. Three samples were excluded from the study because of blood con tamination, The control group was made up of vitreous samples from 15 eyes of 15 normal cadavers and five eyes of five patients who were undergoing vi trectomy for macular hole surgery, RESULTS: Nitrite levels were 0.524 +/- 0.27 mu M and 0.383 +/- 0.17 mu M in the vitreous of patients with proliferative diabetic retinopathy of diabet es type I and type IT, respectively. In 15 cadaver eyes and five vitreous s amples from patients who underwent macular hole surgery, nitrite levels wer e below the detection limit (less than 0.08 mu M) There was no significant difference between nitrite levels in patients with type I and type II diabe tes (P = .56), whereas there was a significant difference between diabetes groups and controls (P < .00001). CONCLUSION: Vitreous nitric oxide levels are elevated in patients with prol iferative diabetic retinopathy with tractional retinal detachment. Nitric o xide may play a role in the pathogenesis of proliferative diabetic retinopa thy. (C) 2000 by Elsevier Science Inc. All rights reserved.