Stimulation of Insulin Signaling Reverses Inflammation-Induced Cone Death in Retinal Detachment

Abstract

Background Rhegmatogenous retinal detachment (RD) involving the macula is a major cause of visual impairment despite high surgical success rate, mainly because of cone death. We and others have shown that cone loss occurs secondary to chronic inflammation in many retinal diseases, including age-related macular degeneration and retinitis pigmentosa. We here investigated the yet unknown mechanisms of inflammation-induced cone death in RD.Methods Vitreous samples from patients with RD and from control patients with macular hole were analyzed to characterize the inflammatory response to RD. A mouse model of RD and retinal explants culture were then used to explore the mechanisms leading to cone death.Results Analysis of vitreous samples shows that RD induces a marked inflammatory response with increased cytokine and chemokine expression in humans, which is closely mimicked by experimental murine RD. In this model, we demonstrate that myeloid cells and T-lymphocytes directly contribute to cone loss, as the inhibition of their accumulation by Thrombospondin 1 increased cone survival. We show that cones are highly dependent on glucose and insulin signaling for survival in vitro and that insulin, and the insulin sensitizers rosiglitazone and metformin, prevent RD-induced cone loss in vivo, despite the persistence of inflammation.Conclusion Our results describe a new mechanism by which inflammation, likely through a combination of competition for glucose and the inhibition of insulin signaling, promotes cone death in RD. Therapeutic inhibition of inflammation and stimulation of insulin signaling might prevent RD-associated cone death until the RD can be surgically repaired and improve visual outcome after RD.Trial registration: ClinicalTrials.gov Identifier NCT03318588