Comparative assessment of angiogenic and cytokine profiles in vitreous samples from patients with diabetic retinopathy and controls

To evaluate and compare the levels of key cytokines and angiogenic factors in the vitreous fluid of patients with clinically confirmed and staged diabetic retinopathy (DR) to those of non-DR controls, with the aim of identifying potential targets for novel therapeutic interventions. Vitreous specimens were collected during 23-gauge vitrectomy from patients diagnosed with diabetic retinopathy (n = 17, at advanced stages requiring surgical intervention) and from control patients (n = 17) undergoing surgery for retinal holes or epiretinal membranes. The samples were analyzed for cytokines (IL-2, IL-4, IL-13, IL-1β, IL-6, and IFN-γ) using ELISA. Angiogenic factors, including placental growth factor (PGF), vascular endothelial growth factor (VEGF), and VEGF-A, were also measured. Statistical comparisons between the DR and control groups were performed. In the DR group, pro-inflammatory cytokines IL-1β (p = 0.04) and IFN-γ (p = 0.06) showed elevated levels compared to controls, indicating an ongoing inflammatory response. No statistically significant differences were observed in IL-6 levels (p = 0.59). The immunomodulatory cytokine IL-13 appeared decreased in the DR group (p = 0.48), although this change was not statistically significant. Similarly, IL-2 (p = 0.74) and IL-4 (p = 0.80) levels did not differ significantly between groups. Angiogenic factors, including PGF, VEGF, and VEGF-A—already well known to be increased in DR—were found to be significantly elevated in DR patients (p < 0.05, p = 0.004), reinforcing their role in the pathophysiology of the disease. These findings highlight an interplay between elevated angiogenic factors and a persistent pro-inflammatory cytokine milieu within the vitreous of patients with advanced DR. While endogenous immunomodulatory mechanisms such as IL-13 are present, they appear insufficient to counteract the active inflammatory and angiogenic processes. Augmenting anti-inflammatory responses or targeting angiogenic mediators may represent a viable therapeutic strategy to improve treatment outcomes in diabetic retinopathy.