Therapeutic potential of Crizanlizumab (anti-P-selectin) in improving sickle cell retinopathy in mice

Abstract

Purpose : Sickle cell retinopathy (SCR) is a major sight debilitating complication of Sickle cell disease (SCD). Very few effective therapies are available to impact SCR. Crizanlizumab (anti-P-selectin; P-Sel) is a novel FDA-approved therapeutic strategy for a pain crisis in SCD patients. Whether this therapy might too be of benefit for other SCD-related complications is not known. Our present studies focused on evaluating the therapeutic potential of P-Sel in a humanized mouse model of SCR.

Methods : Four weeks old male HbAA (normal) and HbSS (sickle cell disease) mice were treated with or without P-Sel (1 or 6 mg/kg, 3 days a week, i.p.) for 5 months. Multiple analyses, including hematology/blood chemistry, retinal imaging studies in live mice (optical coherence tomography; CT, fundoscopy and fluorescein angiography; FA), assessment of retinal function also in live mice (electroretinography; ERG and optokinetic tracking; OKT), histological analyses (hematoxylin and eosin; H&E-staining & leukostasis analyses of adherent immune cells), and RNA (quantitative real-time PCR; qPCR) and protein (Western blotting), immunofluorescence analysis of zonula occludens 1 (ZO-1) expression in retinal flat mounts, and levels of vascular adhesive and/or pro-inflammatory mediators in post-mortem mouse retinal tissue/serum samples were performed.

Results : The data obtained at the end of the study are highly suggestive of robust benefits with respect to the preservation of retinal health and function in HbSS mice in association with chronic P-Sel therapy. Based on various analyses, including long-term, progressive monitoring of the health and function of study mice using in vivo retinal imaging and functional testing modalities, including fundoscopy, FA, OCT, ERG, and OKT, the most remarkable efficacy was achieved using high-dose therapy; however, a significant benefit was detectable also at low-dose. In addition, associated histological, biochemical, hematological, and RNA/protein analyses provided multiple validatory and/or confirmatory evidence in further strong support.

Conclusions : Collectively, our data sets the stage for further, detailed analyses of P-Sel therapy in larger models and/or clinically in human patients as we have found P-Sel therapy to be highly efficacious in protecting and preserving retinal health and function and, importantly, improving the overall health of SS mice.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.