Background Arrhythmogenic cardiomyopathy (AC) is tightly associated with desmosomal mutations in the majority of patients. Arrhythmogenesis in AC patients is likely related to remodeling of cardiac gap junctions and increased levels of fibrosis. Recently, using experimental models, we also identified sodium channel dysfunction secondary to desmosomal dysfunction. The aim of the present study was to assess the immunoreactive signal levels of the sodium channel protein NaV1.5, as well as Connexin43 and Plakoglobin, in myocardial specimens obtained from AC patients. Methods Left and right ventricular free wall (LVFW/RVFW) post-mortem material was obtained from 5 AC patients and 5 age and sex-matched controls. RV septal biopsies (RVSB) were taken from another 15 AC patients. All patients fulfilled the 2010 revised Task Force Criteria for AC diagnosis. Immunohistochemical analyses were performed using antibodies against Connexin43 (Cx43), Plakoglobin, NaV1.5, Plakophilin-2 and N-Cadherin. Results N-Cadherin and Desmoplakin immunoreactive signals and distribution were normal in AC patients compared to control. Plakophilin-2 signals were unaffected unless a PKP2 mutation predicting haploinsufficiency was present. Distribution was unchanged compared to control. Immunoreactive signal levels of PKG, Cx43 and NaV1.5 were disturbed in 74%, 70% and 65% of the patients, respectively. Conclusions Reduced immunoreactive signal of PKG, Cx43 and NaV1.5 at the intercalated disks can be observed in a large majority of the patients. Decreased levels of Nav1.5 might contribute to arrhythmia vulnerability and, in the future, potentially could serve as a new clinically relevant tool for risk assessment strategies.

BackgroundCardiovascular diseases (CVDs) culminating into heart failure (HF) are major causes of death in men and women. Prevalence and manifestation, however, differ between sexes, since men mainly present with coronary artery disease (CAD) and myocardial infarction (MI), and post-menopausal women predominantly present with hypertension. These discrepancies are probably influenced by underlying genetic and molecular differences in structural remodeling pathways involved in hypertrophy, inflammation, fibrosis, and apoptosis. In general, men mainly develop eccentric forms, while women develop concentric forms of hypertrophy. Besides that, women show less inflammation, fibrosis, and apoptosis upon HF. This seems to emerge, at least partially, from the fact that the underlying pathways might be modulated by estrogen, which changes after menopause due to declining of the estrogen levels.ConclusionIn this review, sex-dependent alterations in adverse cardiac remodeling are discussed for various CVDs. Moreover, potential therapeutic options, like estrogen treatment, are reviewed.

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Heart failure with preserved ejection fraction (HFpEF) is a syndrome involving microvascular dysfunction. No treatment is available yet and as the HFpEF patient group is expanding due to the aging population, more knowledge on dysfunction of the cardiac microvasculature is required. Endothelial dysfunction, impaired angiogenesis, (perivascular) fibrosis and the pruning of capillaries (rarefaction) may all contribute to microvascular dysfunction in the heart and other organs, e.g., the kidneys. The HFpEF patient group consists mainly of post-menopausal women and female sex itself is a risk factor for this syndrome. This may point toward a role of estrogen depletion after menopause in the development of HFpEF. Estrogens favor the ratio of vasodilating over vasoconstricting factors, which results in an overall lower blood pressure in women than in men. Furthermore, estrogens improve angiogenic capacity and attenuate (perivascular) fibrosis formation. Therefore, we hypothesize that the drop of estrogen levels after menopause contributes to myocardial microvascular dysfunction and renders post-menopausal women more vulnerable for heart diseases that involve the microvasculature. This review provides a detailed summary of molecular targets of estrogen, which might guide future research and treatment options.