Vitreous cytokine levels in proliferative diabetic retinopathy and cataracts

Abstract

Purpose : The relationships between vitreous cytokines and ocular diseases are not well understood and exploring their interactions may identify future alternate therapies. The purpose of this study is to identify the vitreous cytokines in proliferative diabetic retinopathy (PDR) and age-related cataract (ARC). We performed a prospective observational study of vitreous samples from patients undergoing vitrectomy surgery and analyzed the vitreous specimens for the presence of various cytokines.

Methods : In this study, undiluted vitreous fluid was collected and analyzed from 80 eyes of 80 study participants over the age of 18 undergoing vitrectomy. The vitreous samples were quantitatively measured using ELISA for 37 cytokines as determined by the neuroinflammatory panel kit from Meso Scale Discovery^® (MSD, Rockville, MD) Multispot Assay System. Logistic regression was applied to test the association between ocular disorders and vitreous cytokine levels adjusted for age and sex.

Results : Increased level of VEGF was significantly associated with PDR (β = 0.7; P = 2.4x10^-5). Increased levels of C-reactive protein (CRP), interleukin-15 (IL-15), interleukin-16 (IL-16), serum amyloid-A (SAA), vascular cell adhesion molecule-1 (VCAM-1) and decreased level of basic fibroblast growth factor (bFGF) were also significantly associated with PDR (P < 0.05). In addition, results of a conditional analysis with diabetes suggest an association between IL-15 and ARC, which is independent of diabetes status (β = 0.74; P = 0.04).

Conclusions : Our study suggests that elevated vitreous levels of CRP, IL-15, IL-16, SAA, VCAM-1 and decreased level of bFGF in PDR patients may have synergistic roles with VEGF in diabetic retinopathy progression. While VEGF and VCAM-1 are established as playing a significant role in PDR, to our knowledge the presence of CRP, IL-15, IL-16, and SAA in the vitreous have not been previously identified as being associated with PDR. Evaluation of these inflammatory markers may not only expand our knowledge of pathogenesis of diabetic retinopathy but also serve to augment current treatments. Our study also suggests the presence of an inflammatory marker in ARC formation. Further studies are needed to elucidate the role of IL-15 in cataracts.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.