Inflammatory Mediators in the Pathophysiology of Diabetic Retinopathy (INSPIRE): Study Design and Baseline Characteristics

Purpose: To evaluate inflammatory intraocular and systemic cytokines associated with diabetic retinopathy (DR) and diabetic macular edema (DME). Methods: The INflammatory MediatorS in the PathophysIology of Diabetic REtinopathy (INSPIRE) study is a prospective, placebo-controlled, interventional study that enrolled 328 eyes of 164 adult patients with type II diabetes. 118 (236 eyes) diabetic patients with moderate nonproliferative diabetic retinopathy (NPDR) were randomized to either topical ketorolac 0.45% (Acuvail®) or placebo (Refresh Optive ®, preservative free) in double-masked fashion. A cohort of 23 (46 eyes) patients with diabetes but no retinopathy (No DR) and 23 patients with proliferative diabetic retinopathy (PDR) were also enrolled. All patients underwent complete ophthalmic examination including bilateral aqueous biopsies to test for 24 inflammatory cytokines and 5 classes of prostaglandins. A group of 107 patients without diabetes who were undergoing elective vitrectomy for non-inflammatory conditions had blood and aqueous fluid collected at the time for surgery for cross-comparison analysis. Results: There was similar age and sex distribution across cohorts. The study population was predominantly white. Longer duration of diabetes was observed in the NPDR and PDR groups. The ocular characteristics of all patients were similar for visual acuity, IOP, lens status and median central subfield thickness. Discussion: The INSPIRE study may provide greater understanding of the role of inflammation in DR and allow for the discovery of novel biomarkers and therapeutic targets that can better predict risk of vision loss and prevent progression of DR and DME.