Cytokines and Growth Factors as Predictors of Response to Medical Treatment in Diabetic Macular Edema

Abstract

Diabetic macular edema (DME) is the most common cause of visual loss in patients with diabetes. Antivascular endothelial growth factors (anti-VEGF) agents are first-line therapy for DME. Nevertheless, up to 60% of patients (depending on the anti-VEGF drug used) have an inadequate response to anti-VEGF treatment. Several cytokines are increased in aqueous humor of patients with DME. Differences in response to treatment may be related to baseline cytokine levels. Intravitreal corticosteroids may be used as an alternative to anti-VEGF agents. Steroids have a different pharmacological profile and act on different pathophysiologic mechanisms. Their effect on aqueous humor cytokines is different from the effect of anti-VEGF therapy. This review highlights the major cytokines involved in DME and evaluates whether baseline cytokine levels could be predictors of response to treatment in DME. SIGNIFICANCE STATEMENT: Antivascular endothelial growth factor (anti-VEGF) agents are efficient as diabetic macular edema (DME) treatment. However, in some cases, DME fails to respond to anti-VEGF intravitreal injections. Changes in cytokine levels after treatment supported the idea that other cytokines than VEGF are implicated in DME pathogenesis and could be predictors of response to anti-VEGF treatment or corticosteroids allowing targeted and individualized therapy guided by cytokine levels.