The NLRP3-inflammasome inhibitor MCC950 improves cardiac function in a HFpEF mouse model.

Heart failure with preserved ejection fraction (HFpEF) is posing a significant medical challenge due to its growing prevalence, high hospitalization rates and limited response to current treatment options. Accumulating evidence suggests that a comorbidity-driven systemic pro-inflammatory state, including activation of the NLRP3 inflammasome, contributes to the pathogenesis of HFpEF. This study aimed to investigate the potential cardiac protective effects of the selective NLRP3 inhibitor MCC950, in a mouse model of HFpEF. HFpEF was obtained in 18-22 months old female mice using high-fat diet (HFD) and angiotensin II (AngII) infusion. Mice developed HFpEF and comorbidities such as obesity, type 2 diabetes, and hypertension. MCC950 was added to HFD and groups were treated for four weeks until the study endpoint. MCC950 treatment resulted in lower plasma IL-18 levels (-47.3 %), illustrating target engagement. First, we observed that MCC950 treatment improved left ventricular function, demonstrated by enhanced global longitudinal strain (GLS, 3.9 %, P<0.01) and reverse peak longitudinal strain (RPLSR, +46.8 %, P<0.05). Second, MCC950 reduced cardiac hypertrophy (cardiomyocyte size -19.5 %, P<0.001) and fibrosis (-32.5 %, P<0.05), accompanied by lower expression of pro-fibrotic genes. Finally, MCC950 treatment reduced macrophage infiltration in left ventricular tissue and attenuated macrophage accumulation in visceral adipose tissue, even more as compared to caloric restriction. Overall, this suggests that NLRP3 inhibition could be a promising treatment for HFpEF patients with a pro-inflammatory profile, potentially improving heart function, systemic inflammation, and metabolic parameters.