Abstract 14483: Myeloid Cell Derived IL1b Contributes to Pulmonary Vascular Remodeling in Heart Failure With Preserved Ejection Fraction

Abstract

Introduction: Pulmonary hypertension (PH) in heart failure with preserved ejection fraction (HFpEF) is a common and highly morbid syndrome, but mechanisms driving PH-HFpEF are poorly understood. Hypothesis: We sought to determine whether a well-accepted murine model of HFpEF also displays features of PH, and we sought to identify pathways that might drive early remodeling of the pulmonary vasculature in HFpEF. . Methods: Eight-week-old male and female C57BL/6J mice received either L-NAME and high fat diet (HFD) or control water and diet for 2, 5, and 12 weeks. Db/db mice were studied as a second model of HFpEF. Early pathways regulating PH were identified by bulk and single cell RNA sequencing. Findings were confirmed by immunostain in lungs of mice or lung slides from clinically performed autopsies of PH-HFpEF patients. ELISA was used to verify IL1β in mouse lung, mouse plasma, and also human plasma from PH-HFpEF patients obtained at the time of right heart catheterization. Clodronate liposomes and an anti-IL1β antibody were utilized to deplete macrophages and IL1β, respectively, to assess their impact on pulmonary vascular remodeling in HFpEF in mouse models. Results: L-NAME/HFD treated mice developed PH, small vessel muscularization, and right heart dysfunction. Inflammation-related gene ontologies were over-represented in bulk RNA sequencing analysis of whole lungs, with an increase in CD68 + cells in both murine and human PH-HFpEF lungs. Cytokine profiling showed an increase in IL1β in mouse and human plasma. Finally, clodronate liposome treatment in mice prevented PH in L-NAME/HFD treated mice, and IL1β depletion also attenuated PH in L-NAME/HFD treated mice. Conclusions: We report a novel model for the study of PH and right heart remodeling in HFpEF, and we identify myeloid cell derived IL1β as an important contributor to PH in HFpEF.