Empagliflozin-pirfenidone dual therapy improves cardiac function and structure in a preclinical two-hit HFpEF model

Heart failure with preserved ejection fraction (HFpEF) accounts for more than half of heart failure cases and is associated with substantial morbidity and mortality. Although sodium-glucose cotransporter-2 inhibitors (SGLT2is) have shown efficacy in reducing HFpEF hospitalizations, the disease's multi-pathway pathogenesis often limits the effectiveness of single-target interventions. This study examines whether the cardiovascular benefits of empagliflozin (EMPA) can be synergistically enhanced by co-administration with the targeted anti-fibrotic agent pirfenidone (PFD).

We hypothesized that simultaneous modulation of metabolic stress and pro-fibrotic signaling would lead to synergistic structural and functional recovery in a severe HFpEF phenotype.

HFpEF was induced in Sprague-Dawley rats (n = 16/group) using a two-hit model [NG-nitro-L-arginine methyl ester (L-NAME) and a high-fat diet (HFD)] over 5 weeks. The rats subsequently received daily oral EMPA (0.35 g/kg/d), PFD (0.3 g/kg/d), or combination therapy (EMPA + PFD) for 4 weeks. Treatment efficacy was evaluated via echocardiography, histopathology, and exercise tolerance testing. Further insights into the underlying transcriptional mechanisms were gained through RNA sequencing and semi-quantitative Western blotting. Bliss independence analysis was used to analyze pharmacological synergy.

Co-treatment with EMPA + PFD significantly enhanced diastolic indices, left ventricular ejection fraction (LVEF), fractional shortening (FS), and cardiac output (CO) compared with controls and monotherapy groups (p < 0.05). Histological analysis revealed reduced cardiomyocyte hypertrophy and lower collagen deposition, particularly in the endocardium. Although additive improvement in systemic hemodynamics was observed, EMPA + PFD co-treatment exerted compartmentalized synergy within the myocardium. The combination reversed cellular hypertrophy and deep fibrosis, restoring diastolic and systolic function (p < 0.05). Transcriptomic profiling revealed that local myocardial rescue was mediated by gene networks linked to protein kinase C-activating G-protein-coupled receptor signaling, which blocked the downstream PKC/NF-κB inflammatory pathway and transforming growth factor-beta (TGF-β)-driven fibrosis, thereby explaining the molecular basis of functional improvement.

Dual therapy with EMPA and PFD achieves compartmentalized synergy, effectively eliminating cellular hypertrophy and deep fibrosis, thereby restoring cardiac mechanics. These findings provide mechanistic proof of concept that multi-axis metabolic and antifibrotic combinations can disrupt the complex pathological cycle of HFpEF.