Research led by scientists at Wayne State University, Detroit, Michigan, has demonstrated that salicylate may improve retinal function by enhancing insulin signaling in the retina of type 2 diabetic animal models and in cultured retinal cells. The medicinal properties of salicyclate, an important active ingredient of aspirin, are known to have anti-inflammatory, antipyretic and analgesic properties and previous research had shown their ability to reduce retinal markers of diabetic retinopathy in type 1 diabetes. Testing the compound in trype 2 diabetes models indicated a significant reduction in tumor necrosis factor alpha (TNFα) and suppressor of cytokine signaling 3 (SOCS3) levels, in addition to improving retinal markers of diabetic retinopathy.
The US-led research project aimed to improve the understanding of the changes that occur in the retina in response to altered insulin signaling. As diabetic retinopathy has become the leading cause of vision loss in working age adults there is a considerable global health challenge to be faced by almost all populations in the coming years. Understanding the underlying mechanisms has the ultimate goal of identifying opportunities to interfere with the course of the pathology but also may provide critical information in charting the progression and prognoses in individual patients.
The main objectives of the study were to investigate if salicylate could improve retinal function, as measured by ERG, and investigate the potential mechanism of action if an improved retinal function could be detected following salicylate treatment. In summary, the research results showed that when obese animal models received 2 months of salicylate supplement in their diet, they did not lose their b-wave and oscillatory potential amplitudes when compared to untreated animals. In fact the amplitudes of treated obese models were similar to levels recorded in untreated lean animals. Salicylate also appeared to significantly increase b-wave amplitudes in normal lean animal models. As such, the researchers concluded that salicylate is effective in improving retinal function in a type 2 diabetic model. In respect of the mechanism of action, the research suggested that salicylate may decrease the levels of an important inflammatory kinase and that a reduction in inflammation and oxidative stress could potentially improve insulin signalling in retinal tissues.