Intravitreal injection of COX-2 acetylating immune-resolvents (CAIRs) for the treatment of ocular inflammation in an animal model of uveitis.

Authors: Anastasiya Vinokurtseva, James J. Armstrong, Hong Liu, Patti Kiser, Cindy M. L. Hutnik.

Disclosure Block: A. Vinokurtseva: None. J.J. Armstrong: None. H. Liu: None. P. Kiser: None. C.M.L. Hutnik: None.

Abstract Title:

Intravitreal injection of COX-2 acetylating immune-resolvents (CAIRs) for the treatment of ocular inflammation in an animal model of uveitis.

Abstract Body:

Purpose: Uveitis is an important cause of ocular morbidity, causing a significant reduction in quality of life and leading to significant vision impairment or vision loss in 35% of cases. Currently available strategies to combat underlying inflammation, such as local or systemic corticosteroids, antimetabolites or cytotoxic agents have associated adverse effects as they aim to suppress inflammation, impeding body’s endogenous inflammation-resolving response. Our lab has previously demonstrated that acetylation of cyclooxygenase-2 (COX-2) enzyme redirects its activity from pro-inflammatory to pro-resolving, amplifying inflammation resolution, and reducing more chronic manifestations of inflammation such as scarring and connective tissue changes. Two of the COX-2 acetylating immuno-resolvents (CAIRs) we have evaluated in vitroinclude freshly prepared and rapidly administered (FPRA) acetylsalicylic acid (ASA) and 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.

Study Design: A rat model of LPS-induced uveitis was employed to assess the anti-inflammatory effect of intravitreal (IVT) injections of ASA and APHS compared to vehicle injections in the fellow eye.

Methods: LPS (300ug) was administered subcutaneously to Lewis rats (N=24) 4-hours prior to bilateral 4ul IVT experimental injections. Control animals received PBS subcutaneously as well as IVT OU (N=6), while LPS-induced rats received either ASA (30ug, N=6; or 60ug, N=6) or APHS (500ng, N=6) OD, with PBS OS. Twenty-five hours following LPS-induction, animals were sacrificed and both eyes were histologically processed, cut into 4um sections and stained with hematoxylin and eosin (H&E). Two masked reviewers independently counted the number of infiltrating inflammatory cells to compare between treatment groups. Three to seven fields of view were assessed per animal covering both anterior and posterior segments of the eye.

Results: LPS-induction resulted in signs of systemic inflammation, manifesting as elevated core temperature and acute weight loss (10-20% body weight). Histologically, there was significant inflammatory cell invasion in both the anterior and posterior ocular segments of LPS-treated animals’ eyes with PBS IVT injections. Both ASA and APHS demonstrated significant anti-inflammatory effects - nearly completely mitigating LPS-induced inflammatory cell invasion.

Conclusions: CAIRs through IVT injection resulted in reduced inflammatory infiltrates compared to PBS-treated fellow eyes in a LPS-induced rat model of uveitis. 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.