E-selectin-targeted copolymer as potential therapy for cardiac fibrosis in a mouse model of heart failure with preserved ejection fraction

Nir Lewis ^1,2 Nenad Milošević ³ Olga Tsoref ^1,2 Frederick Epstein ⁴ Ayelet David ³ Jonathan Leor ^1,2

¹Tamman Cardiovascular Research Institute, Sheba Medical Center, Israel
²Neufeld Cardiac Research Institute, Faculty of Medicine, Tel Aviv University, Israel
³Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel
⁴Department of Biomedical Engineering, University of Virginia, USA

Background: Endothelial activation and dysfunction triggered by low-grade, systemic inflammation is a critical step in the pathogenesis of heart failure with preserved ejection fraction (HFpEF). In HFpEF, the adhesion molecule E-selectin is expressed on the activated endothelium and plays a key role in leukocyte rolling and migration, leading to inflammation, oxidative stress, myofibroblast activation and cardiac fibrosis.

Objective: To test the hypothesis that an E-selectin-targeted copolymer would attenuate cardiac fibrosis in a mouse model of HFpEF.

Methods and results: To induce HFpEF in 12-week-old male C57BL/6 mice, we implanted subcutaneous osmotic pumps for continuous infusion of angiotensin-II (2 mg / kg / d). To target E-selectin, we administered intraperitoneal injections of an N-(2-hydroxypropyl) methacrylamide-based E-selectin binding copolymer (P-Esbp) (0.5 mg / 0.2 ml), a control, non-specific copolymer (P-Scrm), or saline, once a week for 4 weeks.

Serial echocardiography studies revealed left ventricular hypertrophy with preserved ejection fraction in both groups. Ex-vivo imaging of whole hearts using an IVIS Lumina Series imaging system confirmed that near-infrared fluorescent-labeled P-Esbp targeted the diseased hearts. Microscopic examination confirmed that fluorescein isothiocyanate-labeled P-Esbp specifically targeted endothelial cells in the heart. Subsequently, P-Esbp reduced interstitial and perivascular cardiac fibrosis, as measured by post-mortem histology; these effects, however, did not reach statistical significance.

Conclusions: Our preliminary results show, for the first time, that an E-selectin-targeted copolymer can target vascular cardiac inflammation. Our findings confirm the important roles of E-selectin and vascular inflammation in cardiac fibrosis, and suggest a new target for the treatment of HFpEF.