Optimized murine HFpEF models for translational preclinical studies.

Abstract

INTRODUCTION: The most clinically representative murine models of heart failure with preserved ejection fraction (HFpEF) include a '2-hit' model combining nitrosative stress with metabolic perturbation and a '3-hit' model that also includes ageing. Both models have important limitations with regard to substrain and sex. METHODS: The 2-hit model protocol was modified to reproduce HFpEF in both C57BL/6N and 6J mice by increasing L-NAME doses (0.5 g/L to 1.75 g/L) and protocol lengths (7 weeks to 13 weeks). For the 3-hit model, in addition to deoxycorticosterone pivalate (DOCP), we added 1% NaCl drinking water to enhance and prolong the effect of DOCP ('4-hit'). To maintain the phenotype, a second bolus of DOCP was administered after 8 weeks. RESULTS: HFpEF was successfully induced in C57BL/6J mice when exposed to a 13-week 2-hit L-NAME protocol with gradually increasing dosage from 1.0 to 1.75 g/L. For the 4-hit mice, a clear HFpEF phenotype was observed in C57BL/6N and 6J mice in both male and females, and maintained for up to 12 weeks. CONCLUSION: These modifications ensure the 2-hit model is induced in J substrain of C57BL/6 mice. The 4-hit model prevents aldosterone escape and enhances reproducibility across sexes and substrains.