Abstract
Purpose :
The etiology and progression of diabetic retinopathy (DR) remains a complex enigma. In DR patients, the vitreous clinical biochemistry has not yet been reported. The biochemical changes occurring at the site of DR are paramount in understanding the pathophysiology of DR. We hypothesize a derangement in the vitreous biochemistry (metabolites, antioxidants & proliferative markers) in DR patients, which would enhance the understanding of the progression of DR.
Methods :
A prospective, cross sectional study of vitreous and plasma samples from DR patients (n=29) and controls (C) (n=27) undergoing vitrectomy. Each sample was analyzed for biochemical markers (glucose, cholesterol, triglycerides, total protein (TP), urea, creatinine, albumin, aspartate transaminase, alanine transaminase, micro protein urea, uric acid, γ glutamyl transferase, phosphate, calcium, creatine kinase (CK) and lactate dehydrogenase-LDH) using the Clinical chemistry analyzer (Benespera, USA), zeaxanthin (ZEA-most abundant antioxidant in the macula of eye) using HPLC (Agilent Technologies, USA) and proliferative markers [vascular endothelial growth factor (VEGF) and VEGF receptor 1 (VEGFR1)] using ELISA (Ray Biotech, USA). Two tailed Student’s t-test was used for statistical analysis.
Results :
Glucose (DR:49.27±27.78mg/dl, C:20.81±14.38mg/dl; P<0.001), cholesterol (DR:1.24±1.72 mg/dl, C:0.29±0.95 mg/dl; P<0.05), TP (DR 0.25±0.24 g/dl, C:0.1±0.11 g/dl; P<0.01), CK (DR:5.2±7.38 U/L, C:0.15±0.52 U/L; P<0.05) and LDH (DR:175.8±125.70 U/L, C:40.42±33.55 U/L; P< 0.01) were significantly increased in vitreous of DR vs. C. Creatinine was significantly (P<0.01) increased in plasma of DR vs. C. ZEA was significantly (P< 0.01) reduced in vitreous of DR (0.28±0.04 µg/ml) vs. C (0.36±0.09 µg/ml). ZEA was significantly (P<0.01) reduced in plasma of DR (0.32±0.04 µg/ml) vs. C (0.38±0.05 µg/ml). ZEA was significantly (P<0.05) reduced in DR vitreous vs. DR plasma. Further, trends reported in literature were observed for VEGF and VEGFR1 markers with no significant differences.
Conclusions :
DR is a morbid disorder with evident deranged vitreous biochemistry typical of a metabolic disorder. Glucose, Cholesterol, TP, CK and LDH may be novel diagnostic/therapeutic targets in DR. ZEA, is a novel antioxidant and might be a critical diagnostic marker of therapeutic value in DR.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.