Abstract
Purpose: :
To evaluate and compare Nerve Growth Factor (NGF) vitreal levels in various retinal diseases.
Methods: :
Sixty nine patients were selected for the study and vitreous samples were obtained during surgery. 23 patients had proliferative vitreoretinopathy and 36 patients had proliferative diabetic retinopathy. Epiretinal membranes (ERM) were obtained from 10 patients to be used as controls. ELISA, a sensitive technique for accurately determining the amount of protein in a given sample by means of an enzyme–catalyzed color change was used to determine the amount of Nerve Growth factor in each vitreous sample by comparing against a standard curve to obtain the concentration of NGF protein in the sample
Results: :
NGF level was significantly elevated in the PDR samples as compared to the PVR samples and controls. The PVR samples had a mean NGF concentration of 126.28 pg/ml, PDR samples had a mean NGF concentration of 1244.56 pg/ml and the control ERM samples had a concentration of 56.28 pg/ml. The median NGF concentration in PVR and control samples was 132.08 and 42.65 respectively as opposed to a median of 1803.35 in PDR samples. NGF was low or undetectable in 3/10 controls. Kruskall Wallis and Dunn’s statsitical tests revealed a statistically significant difference (p<0.05) among the three groups
Conclusions: :
Patients with proliferative diabetic retinopathy and vitreoretinopathy have increased levels of vitreal Nerve growth factor. Several studies have shown raised NGF levels to be associated with hypoxia. Chronic hypoxia seen in PDR may be one of the factors for the increased NGF levels observed in PDR. NGF may be used, to screen and determine the severity of proliferative diabetic retinopathy
Keywords: retina • diabetic retinopathy • proliferative vitreoretinopathy