Diabetic retinopathy and the role of Omega-3 PUFAs: A narrative review

Diabetes mellitus has been a major cause of concern for the past few decades. As the number of diabetic patients increases, so too does the occurrence of its complications. Diabetic retinopathy (DR) is one of these and constitutes the most common cause of blindness amongst working-age individuals. Chronic exposure to a hyperglycaemic environment remains the driving force of a cascade of molecular events that disrupt the microvasculature of the retina and if left untreated can lead to blindness. In this review, we identify oxidative stress as a major implication in the pathway to the development of DR and speculate that it plays a central role especially in the early stages of the disease. Cells lose their antioxidant capacity under a hyperglycaemic state, free radicals are formed and eventually apoptosis ensues. The polyol pathway; advanced glycation end-product formation; the protein kinase C pathway, and the hexosamine pathway are found to contribute to the increase in oxidative stress observed in diabetic patients. We also investigate the use of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) in DR. These molecules possess antioxidant and anti-inflammatory properties and have been previously investigated for use in other ocular pathologies with promising results. In this review we present the latest findings in pre-clinical and clinical studies for the use of ω-3 PUFAs in DR. We hypothesise that ω-3 PUFAs could be beneficial for DR in ways of reducing the oxidative stress and limiting the progression of the disease that threatens the eyesight of the patient, in conjunction with conventional therapy.