McNamara, Dennis M

This study uncovers a previously unrecognized role for NAV3 in TGF-β1-driven cardiac fibroblast activation. We show that NAV3 facilitates profibrotic remodeling through noncanonical signaling and cell cycle arrest, independently of SMAD2/3. These findings position NAV3 as a novel regulator of fibroblast phenotype and a potential modulator of cardiac fibrosis.

Abstract Introduction Cannabidiol has been shown to exert significant anti-inflammatory effects and has demonstrated efficacy in murine models of autoimmune myocarditis, pericarditis, and heart failure. The ARCHER Study assessed whether a pharmaceutically produced cannabidiol formulation showed beneficial effects on cardiac magnetic resonance (CMR) endpoints known to predict prognosis in this patient population. Methods In a multicentre international double-blind placebo-controlled phase 2 study, we randomly assigned 109 patients within 10 days of CMR confirmed diagnosis of acute myocarditis to 12 weeks of pharmaceutically produced oral cannabidiol (active) or placebo. Dose was titrated up to 10 mg/kg of body weight twice daily. Primary endpoints were the difference in extracellular volume (ECV) and global longitudinal strain (GLS) measured by CMR at week 12. Other CMR endpoints included left-ventricular ejection fraction (LVEF), LV mass, intracellular volume (ICV), LV end-diastolic and end-systolic volumes (LVEDV, LVESV), and left-atrial end-systolic volume (LAESV). Results All randomized patients (56 active/53 placebo) completed the study with no loss to follow-up. Study drug appeared safe and well tolerated. Baseline mean ECV 38.9 ± 10.9 ml, GLS −15.3 ± 3.6%, and LVEF 60.6 ± 9.9% were consistent with mild to moderate myocarditis and predominantly intact LV function. Week 12 mean ECV was 33.6 ml in the active group and 37.3 ml in the placebo group, a difference of −3.7 ml, confidence interval (CI): −7.4 to 0.1; P = .0538; GLS was −16.0% in the active group and −15.9% in the placebo group, difference of −0.1, CI: −1.2 to 1.1; P = .90. Left ventricular mass was significantly reduced in the active group at 121.1 g compared to placebo 130.3 g, a difference of −9.2, CI: −16.4 to −2.1; P = .0117. In terms of remodelling, LAESV was significantly reduced in the active group (−8.1 ml; P = .0376) while the reduction in LVEDV failed to reach significance (−7.4 ml; P = .098). Conclusion In mild-to-moderate acute myocarditis, treatment with pharmaceutically manufactured cannabidiol was not associated with a statistically significant change in myocardial ECV or GLS, although a trend towards reduction in ECV was observed. In addition, improvement in other potential markers of myocardial recovery, including a significant reduction in LV mass, was seen in the active treatment group. Further investigation of the therapeutic potential of this therapy in inflammatory cardiac conditions is warranted.

Peripartum cardiomyopathy (PPCM) is an idiopathic form of pregnancy-induced heart failure associated with preeclampsia. Circulating factors in late pregnancy are thought to contribute to both diseases, suggesting a common underlying pathophysiological process. However, what drives this process remains unclear. Using serum proteomics, we identified the senescence-associated secretory phenotype (SASP), a marker of cellular senescence associated with biological aging, as the most highly up-regulated pathway in young women with PPCM or preeclampsia. Placentas from women with preeclampsia displayed multiple markers of amplified senescence and tissue aging, as well as overall increased gene expression of 28 circulating proteins that contributed to SASP pathway enrichment in serum samples from patients with preeclampsia or PPCM. The most highly expressed placental SASP factor, activin A, was associated with cardiac dysfunction or heart failure severity in women with preeclampsia or PPCM. In a murine model of PPCM induced by cardiomyocyte-specific deletion of the gene encoding peroxisome proliferator–activated receptor γ coactivator-1α, inhibiting activin A signaling in the early postpartum period with a monoclonal antibody to the activin type II receptor improved heart function. In addition, attenuating placental senescence with the senolytic compound fisetin in late pregnancy improved cardiac function in these animals. These findings link senescence biology to cardiac dysfunction in pregnancy and help to elucidate the pathogenesis underlying cardiovascular diseases of pregnancy.