Peripartum cardiomyopathy (PPCM) is a life-threatening pregnancy-associated cardiomyopathy in previously healthy women. Although PPCM is driven in part by the 16-kDa N-terminal prolactin fragment (16K PRL), the underlying molecular mechanisms are poorly understood. We found that 16K PRL induced microRNA-146a (miR-146a) expression in ECs, which attenuated angiogenesis through downregulation of NRAS. 16K PRL stimulated the release of miR-146a-loaded exosomes from ECs. The exosomes were absorbed by cardiomyocytes, increasing miR-146a levels, which resulted in a subsequent decrease in metabolic activity and decreased expression of Erbb4, Notch1, and Irak1. Mice with cardiomyocyte-restricted Stat3 knockout (CKO mice) exhibited a PPCM-like phenotype and displayed increased cardiac miR-146a expression with coincident downregulation of Erbb4, Nras, Notch1, and Irak1. Blocking miR-146a with locked nucleic acids or antago-miRs attenuated PPCM in CKO mice without interrupting full-length prolactin signaling, as indicated by normal nursing activities. Finally, miR-146a was elevated in the plasma and hearts of PPCM patients, but not in patients with dilated cardiomyopathy. These results demonstrate that miR-146a is a downstream-mediator of 16K PRL that could potentially serve as a biomarker and therapeutic target for PPCM.
Diffuse myocardial fibrosis in hypertrophic cardiomyopathy can be identified by cardiovascular magnetic resonance, and is associated with left ventricular diastolic dysfunction.
- Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance
- Published over 7 years ago
BACKGROUND: The presence of myocardial fibrosis is associated with worse clinical outcomes in hypertrophic cardiomyopathy (HCM). Cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) sequences can detect regional, but not diffuse myocardial fibrosis. Post-contrast T1 mapping is an emerging CMR technique that may enable the non-invasive evaluation of diffuse myocardial fibrosis in HCM. The purpose of this study was to non-invasively detect and quantify diffuse myocardial fibrosis in HCM with CMR and examine its relationship to diastolic performance. METHODS: We performed CMR on 76 patients - 51 with asymmetric septal hypertrophy due to HCM and 25 healthy controls. Left ventricular (LV) morphology, function and distribution of regional myocardial fibrosis were evaluated with cine imaging and LGE. A CMR T1 mapping sequence determined the post-contrast myocardial T1 time as an index of diffuse myocardial fibrosis. Diastolic function was assessed by transthoracic echocardiography. RESULTS: Regional myocardial fibrosis was observed in 84% of the HCM group. Post-contrast myocardial T1 time was significantly shorter in patients with HCM compared to controls, consistent with diffuse myocardial fibrosis (498 +/- 80 ms vs. 561 +/- 47 ms, p < 0.001). In HCM patients, post-contrast myocardial T1 time correlated with mean E/e' (r = -0.48, p < 0.001). CONCLUSIONS: Patients with HCM have shorter post-contrast myocardial T1 times, consistent with diffuse myocardial fibrosis, which correlate with estimated LV filling pressure, suggesting a mechanistic link between diffuse myocardial fibrosis and abnormal diastolic function in HCM.
BACKGROUND: Heart failure (HF) patients have a high risk of death, and implantable cardioverter defibrillators (ICDs) are effective in preventing sudden cardiac death (SCD). However, a certain percentage of patients may not be immediate candidates for ICDs, particularly those having a short duration of risk or an uncertain amount of risk. This includes the newly diagnosed patients, as well as those on the cardiac transplant list or NYHA class IV heart failure patients who do not already have an ICD. In these patients, a wearable cardioverter defibrillator (WCD) may be used until long term risk of SCD is defined. The purpose of this study was to determine the incidence of SCD in this population, and the efficacy of early defibrillation by a WCD. METHODS: Ten enrolling centers identified 89 eligible HF patients who were either listed for cardiac transplantation, diagnosed with dilated cardiomyopathy, or receiving inotropic medications. Data collected included medical history, device records, and outcomes (including 90 day mortality). RESULTS: Out of 89 patients, final data on 82 patients has been collected. Patients wore the device for 75+/-58 days. Mean age was 56.8+/-13.2, and 72% were male. Most patients (98.8%) were diagnosed with dilated cardiomyopathy with a low ejection fraction (<40%) and twelve were listed for cardiac transplantation. Four patients were on inotropes. There were no sudden cardiac arrests or deaths during the study. Interestingly, 41.5% of patients were much improved after WCD use, while 34.1% went on to receive an ICD. CONCLUSIONS: In conclusion, the WCD monitored HF patients until further assessment of risk. The leading reasons for end of WCD use were improvement in left ventricular ejection fraction (LVEF) or ICD implantation if there was no significant improvement in LVEF.
Microsphere embolisation as an alternative for alcohol in percutaneous transluminal septal myocardial ablation
- Netherlands heart journal : monthly journal of the Netherlands Society of Cardiology and the Netherlands Heart Foundation
- Published almost 7 years ago
BACKGROUND: Percutaneous transluminal septal myocardial ablation using microsphere embolisation is a new interventional technique to treat patients with hypertrophic obstructive cardiomyopathy. METHODS AND RESULTS: In two patients, considered at high risk for myectomy, targeted septal perforators were occluded with microsphere embolisation instead of alcohol ablation to reduce left ventricular outflow gradient. In both cases the left ventricular outflow tract gradient was immediately reduced. No adverse events occurred. CONCLUSION: This is the first clinical experience with Embozene® Microspheres in the Netherlands as an alternative for alcohol septal ablation. In both cases it resulted in immediate improvement in the haemodynamics, without any adverse events.
Background Peripartum cardiomyopathy shares some clinical features with idiopathic dilated cardiomyopathy, a disorder caused by mutations in more than 40 genes, including TTN, which encodes the sarcomere protein titin. Methods In 172 women with peripartum cardiomyopathy, we sequenced 43 genes with variants that have been associated with dilated cardiomyopathy. We compared the prevalence of different variant types (nonsense, frameshift, and splicing) in these women with the prevalence of such variants in persons with dilated cardiomyopathy and with population controls. Results We identified 26 distinct, rare truncating variants in eight genes among women with peripartum cardiomyopathy. The prevalence of truncating variants (26 in 172 [15%]) was significantly higher than that in a reference population of 60,706 persons (4.7%, P=1.3×10(-7)) but was similar to that in a cohort of patients with dilated cardiomyopathy (55 of 332 patients [17%], P=0.81). Two thirds of identified truncating variants were in TTN, as seen in 10% of the patients and in 1.4% of the reference population (P=2.7×10(-10)); almost all TTN variants were located in the titin A-band. Seven of the TTN truncating variants were previously reported in patients with idiopathic dilated cardiomyopathy. In a clinically well-characterized cohort of 83 women with peripartum cardiomyopathy, the presence of TTN truncating variants was significantly correlated with a lower ejection fraction at 1-year follow-up (P=0.005). Conclusions The distribution of truncating variants in a large series of women with peripartum cardiomyopathy was remarkably similar to that found in patients with idiopathic dilated cardiomyopathy. TTN truncating variants were the most prevalent genetic predisposition in each disorder.
When transplanted into failing heart, autologous somatic tissue-derived cells yield functional recovery via paracrine effects that enhance native regeneration. However, the therapeutic effects are modest. We developed a method in which scaffold-free cell sheets are attached to the epicardial surface to maximize paracrine effects. This Phase I clinical trial tested whether transplanting autologous cell-sheets derived from skeletal muscle is feasible, safe, and effective for treating severe congestive heart failure.
BACKGROUND: As Chagas disease continues to expand beyond tropical and subtropical zones, a growing need exists to better understand its resulting economic burden to help guide stakeholders such as policy makers, funders, and product developers. We developed a Markov simulation model to estimate the global and regional health and economic burden of Chagas disease from the societal perspective. METHODS: Our Markov model structure had a 1 year cycle length and consisted of five states: acute disease, indeterminate disease, cardiomyopathy with or without congestive heart failure, megaviscera, and death. Major model parameter inputs, including the annual probabilities of transitioning from one state to another, and present case estimates for Chagas disease came from various sources, including WHO and other epidemiological and disease-surveillance-based reports. We calculated annual and lifetime health-care costs and disability-adjusted life-years (DALYs) for individuals, countries, and regions. We used a discount rate of 3% to adjust all costs and DALYs to present-day values. FINDINGS: On average, an infected individual incurs US$474 in health-care costs and 0·51 DALYs annually. Over his or her lifetime, an infected individual accrues an average net present value of $3456 and 3·57 DALYs. Globally, the annual burden is $627·46 million in health-care costs and 806 170 DALYs. The global net present value of currently infected individuals is $24·73 billion in health-care costs and 29 385 250 DALYs. Conversion of this burden into costs results in annual per-person costs of $4660 and lifetime per-person costs of $27 684. Global costs are $7·19 billion per year and $188·80 billion per lifetime. More than 10% of these costs emanate from the USA and Canada, where Chagas disease has not been traditionally endemic. A substantial proportion of the burden emerges from lost productivity from cardiovascular disease-induced early mortality. INTERPRETATION: The economic burden of Chagas disease is similar to or exceeds those of other prominent diseases globally (eg, rotavirus $2·0 billion, cervical cancer $4·7 billion) even in the USA (Lyme disease $2·5 billion), where Chagas disease has not been traditionally endemic, suggesting an economic argument for more attention and efforts towards control of Chagas disease. FUNDING: Bill & Melinda Gates Foundation, the National Institute of General Medical Sciences Models of Infectious Disease Agent Study.
Dilated cardiomyopathy (DCM) is a common form of cardiomyopathy causing systolic dysfunction and heart failure. Rare variants in more than 30 genes, mostly encoding sarcomeric proteins and proteins of the cytoskeleton, have been implicated in familial DCM to date. Yet, the majority of variants causing DCM remain to be identified. The goal of the study is to identify novel mutations causing familial dilated cardiomyopathy.
Takotsubo syndrome (TTS) is characterized by an acute left ventricular dysfunction and is associated with life-threating complications in the acute phase. The underlying disease mechanism in TTS is still unknown. A genetic basis has been suggested to be involved in the pathogenesis.
The heart either hypertrophies or dilates in response to familial mutations in genes encoding sarcomeric proteins, which are responsible for contraction and pumping. These mutations typically alter calcium-dependent tension generation within the sarcomeres, but how this translates into the spectrum of hypertrophic versus dilated cardiomyopathy is unknown. By generating a series of cardiac-specific mouse models that permit the systematic tuning of sarcomeric tension generation and calcium fluxing, we identify a significant relationship between the magnitude of tension developed over time and heart growth. When formulated into a computational model, the integral of myofilament tension development predicts hypertrophic and dilated cardiomyopathies in mice associated with essentially any sarcomeric gene mutations, but also accurately predicts human cardiac phenotypes from data generated in induced-pluripotent-stem-cell-derived myocytes from familial cardiomyopathy patients. This tension-based model also has the potential to inform pharmacologic treatment options in cardiomyopathy patients.