Dietary Nitrate Prevents Cardiac Dysfunction in HFrEF by Improving Hemodynamics, Ameliorating Remodeling, and Resolving Inflammation

Abstract

Aims: Impaired cardiac function, reduced nitric oxide (NO) bioavailability, and inflammation are key contributors to the pathogenesis and progression of heart failure with reduced ejection fraction (HFrEF). This study aimed to investigate whether dietary inorganic nitrate supplementation can attenuate cardiac dysfunction and adverse remodeling in HFrEF by enhancing NO signaling.

Methods: Two mouse models of HFrEF, induced by myocardial infarction (MI) or transverse aortic constriction (TAC), were treated with dietary nitrate or a control diet for 4-6 weeks, initiating the treatment on day 3 after myocardial injury. Echocardiography and pressure volume (PV) loop analysis were employed to assess cardiac function and hemodynamics. Histology staining was performed to assess the degree of cardiac fibrosis. Myograph experiments were conducted to assess aortic vasorelaxation. Biomarkers related to hypertrophy, fibrosis, and inflammation were analyzed in cardiac tissues through Q-PCR analysis and immunofluorescence staining.

Results: In HFrEF mice, long-term inorganic nitrate treatment increased systolic and diastolic function, enhanced vascular relaxation, and reduced both replacement and reactive fibrosis. In the nitrate group, cardiac gene expression showed downregulation of hypertrophy-, fibrosis-, and inflammation-related markers, alongside upregulation of anti-inflammatory markers associated with M1-to-M2 macrophage polarization. Immunofluorescence confirmed reduced fibrosis and increased anti-inflammatory protein biomarkers associated with increased serum nitrate and cardiac cGMP levels.

Conclusions: Early initiation of dietary nitrate supplementation after myocardial injury enhances cardiac and vascular function, reduces fibrosis and inflammation, and holds promise as a cardioprotective strategy to reduce the progression of HFrEF through NO-signaling.