Abstract
Purpose :
Current treatments for uveitis lack adequate efficacy and impede the body’s endogenous inflammation-resolution. Targeted acetylation of cyclooxygenase-2 (COX-2) enzyme redirects its activity from pro-inflammatory to pro-resolving, amplifying resolution of the acute phase of inflammation, and mitigating sequelae of chronic inflammation such as scarring and connective tissue changes. COX-2 acetylating immuno-resolvents (CAIRs) are agents capable of specifically acetylating COX-2 and include locally delivered acetylsalicylic acid (ASA) as well as a more potent derivative compound, o-(acetoxyphenyl)hept-2-ynyl sulfide (APHS). We hypothesized that intravitreal injection of CAIRs would reduce histological markers of inflammation in an animal model of uveitis and reduce expression of pro-inflammatory genes in THP-1 macrophages.
Methods :
Lipopolysaccharide (LPS) or vehicle was administered subcutaneously to Lewis rats 6 hours prior to intravitreal (IVT) experimental injections. Control animals received vehicle IVT OU while LPS-induced rats received either IVT ASA or APHS OD, with vehicle OS. 25 hours following LPS-induction, both eyes underwent histopathological assessment of the anterior and posterior segments. Effects of experimental treatments on cytokine production were assessed in vitro with phorbol 12-myristate 13-acetate (PMA)-induced THP-1 macrophages. Cells were co-treated for 6 hours with LPS and either ASA or APHS. Total RNA was extracted and expression of pro-inflammatory markers IL-1β, TNFα and COX-2 was assessed via RT-qPCR.
Results :
Eyes of LPS-treated animals, receiving CAIRs IVT showed marked reduction in inflammatory cell infiltration in both anterior and posterior ocular segments, compared to vehicle-treated contralateral eyes of the same animals. In vitro, LPS-treated macrophages demonstrated significant upregulation in inflammatory cytokines IL-1β, TNFα and COX-2; CAIRs counteracted this effect in a dose-dependent manner.
Conclusions :
CAIRs were well-tolerated and efficacious in this rat model of endotoxin-induced uveitis. They also demonstrated significant efficacy in vitro, reducing macrophage pro-inflammatory signaling. These compounds show initial promise as potential novel inflammation-resolving treatments. Next steps are to compare the safety and efficacy of CAIRs to current clinical therapies within this model.
This is a 2021 ARVO Annual Meeting abstract.