Background: Systemic biochemical disarray has been implicated in the pathogenesis
and progression of diabetes and its complications. However, the modifications in the metabolic
state of the retina and its microenvironment in response to the systemic metabolic malfunction has
not been documented.
Objective: The objective of the present study was to document the various biomarkers that may be
involved in the pathogenesis and progression of Proliferative Diabetic Retinopathy (PDR).
Method: The vitreous humour and plasma samples from 38 PDR, 7 Proliferative Vitreo Retinopathy
(PVR) and 17 control patients undergoing pars plana vitrectomy were analysed for sixteen different
biomarkers. Whole genome Single Nucleotide Polymorphism (SNP) microarray was performed
on ten PDR patients’ peripheral blood samples.
Results: The vitreous humour glucose, creatinine, micro protein, phosphorus and lactate dehydrogenase
were found significantly increased in the PDR patients compared to controls. The plasma
urea, creatinine and micro protein were also significantly increased. The plasma phosphorus of
PDR patients on oral hypoglycemic therapy was found significantly decreased compared with PDR
patients on insulin therapy and controls. SNPs previously associated with glucose (5), lactate dehydrogenase
(2) and creatinine (2) levels were identified to be polymorphic homozygous (minor allele)
in ≥ 60% patients in this study, suggesting enhanced susceptibility.
Conclusion: The metabolic overactivity of the retinal microenvironment appears to play a vital role
in the pathogenesis of PDR. The significantly elevated biomarkers may have diagnostic, prognostic
and therapeutic significance. These findings shed light on the biochemical disarray in the vitreous
humour of PDR patients that could have significant management implications.