Yilu Wang

Polymorphisms of ACE2 Gene are Associated With Essential Hypertension and Antihypertensive Effects of Captopril in Women

ACE2 appears to counterbalance the vasopressor effect of angiotensin I converting enzyme (ACE) in the renin‐angiotensin system. We hypothesized that ACE2 polymorphisms could confer a high risk of hypertension and have an impact on the antihypertensive response to ACE inhibitors. The hypothesis was tested in two case‐control studies and a clinical trial of 3,408 untreated hypertensive patients randomized to Atenolol, Hydrochlorothiazide, Captopril, or Nifedipine treatments for 4 weeks. ACE2 rs2106809 T allele was found to confer a 1.6‐fold risk for hypertension in women (95% confidence interval (CI), 1.13–2.06), whereas when combined with the effect of the ACE DD genotype, the risk was 2.34‐fold (95% CI, 1.75–4.85) in two independent samples. The adjusted diastolic blood pressure response to Captopril was 3.3 mm Hg lower in ACE2 T allele carriers than in CC genotype carriers (P=0.019) in women. We conclude that the ACE2 T allele confers a high risk for hypertension and reduced antihypertensive response to ACE inhibitors.

MiR-221 promotes cardiac hypertrophy in vitro through the modulation of p27 expression.

Cardiac hypertrophy has been known as an independent predictor for cardiovascular morbidity and mortality. Molecular mechanisms underlying the development of heart failure remain elusive. Recently, microRNAs (miRs) have been established as important regulators in cardiac hypertrophy. Here, we reported miR‐221 was up‐regulated in both transverse aortic constricted mice and patients with hypertrophic cardiomyopathy (HCM). Forced expression of miR‐221 by transfection of miR‐221 mimics increased myocyte cell size and induced the re‐expression of fetal genes, which were inhibited by the knockdown of endogenous miR‐221 in cardiomyocytes. The TargetScan algorithm‐based prediction identified that p27, a cardiac hypertrophic suppressor, is the putative target of miR‐221, which was confirmed by luciferase assay and Western blotting.

MiR-451 is decreased in hypertrophic cardiomyopathy and regulates autophagy by targeting TSC1.

The molecular mechanisms that drive the development of cardiac hypertrophy in hypertrophic cardiomyopathy (HCM) remain elusive. Accumulated evidence suggests that microRNAs are essential regulators of cardiac remodelling. We have been suggested that microRNAs could play a role in the process of HCM. To uncover which microRNAs were changed in their expression, microRNA microarrays were performed on heart tissue from HCM patients (n = 7) and from healthy donors (n = 5). Among the 13 microRNAs that were differentially expressed in HCM, miR‐451 was the most down‐regulated. Ectopic overexpression of miR‐451 in neonatal rat cardiomyocytes (NRCM) decreased the cell size, whereas knockdown of endogenous miR‐451 increased the cell surface area. Luciferase reporter assay analyses demonstrated that tuberous sclerosis complex 1 (TSC1) was a direct target of miR‐451. Overexpression of miR‐451 in both HeLa cells and NRCM suppressed the expression of TSC1. Furthermore, TSC1 was significantly up‐regulated in HCM myocardia, which correlated with the decreased levels of miR‐451. As TSC1 is a known positive regulator of autophagy, we examined the role of miR‐451 in the regulation of autophagy. Overexpression of miR‐451 in vitro inhibited the formation of the autophagosome. Conversely, miR‐451 knockdown accelerated autophagosome formation. Consistently, an increased number of autophagosomes was observed in HCM myocardia, accompanied by up‐regulated autophagy markers, and the lipidated form of LC3 and Beclin‐1. Taken together, our findings indicate that miR‐451 regulates cardiac hypertrophy and cardiac autophagy by targeting TSC1. The down‐regulation of miR‐451 may contribute to the development of HCM and may be a potential therapeutic target for this disease.

Correlation of ventricular arrhythmias with genotype in arrhythmogenic right ventricular cardiomyopathy.

Background—Although mutations of several genes are associated with arrhythmogenic right ventricular cardiomyopathy (ARVC), the exact correlation between genotype and ventricular arrhythmia features remains unclear. This study was aimed to examine the possible association of the 9 known genes of ARVC with clinical and electrophysiological characteristics. Methods and Results—Ninety subjects diagnosed with ARVC who underwent electrophysiological study were recruited for screening the 9 known ARVC-causing genes. A total of 53 mutations were identified in 57 (63%) subjects. Mutation carriers had more frequent clinical ventricular tachycardia (VT; 89% versus 55%; P<0.001) and negative T waves in V1 to V3 (61% versus 33%; P=0.016). Subjects with plakophilin-2 (PKP2) mutations also had more frequent VT than those without mutations in PKP2. Comparison between subjects with multiple and single mutations showed that syncope occurred more often in the former group (58% versus 24%; P=0.018). VT was significantly more often induced in mutation carriers compared with noncarriers (75% versus 39%; P=0.001), as well as in PKP2 mutation carriers compared with subjects without PKP2 mutations (80% versus 48%; P=0.002). Induced VT with a rate ≥200 bpm was more often documented in mutation carriers (88% versus 54%; P=0.013), as well as in PKP2 mutation carriers (91% versus 67%; P=0.041). Conclusions—Pathogenic gene mutations were found in nearly two thirds of subjects diagnosed with ARVC. Mutation carriers, especially PKP2, had a higher proportion of a history of VT and more inducible fast VT.

Rare Variants in Genes Encoding MuRF1 and MuRF2 Are Modifiers of Hypertrophic Cardiomyopathy

Modifier genes contribute to the diverse clinical manifestations of hypertrophic cardiomyopathy (HCM), but are still largely unknown. Muscle ring finger (MuRF) proteins are a class of muscle-specific ubiquitin E3-ligases that appear to modulate cardiac mass and function by regulating the ubiquitin-proteasome system. In this study we screened all the three members of the MuRF family, MuRF1, MuRF2 and MuRF3, in 594 unrelated HCM patients and 307 healthy controls by targeted resequencing. Identified rare variants were confirmed by capillary Sanger sequencing. The prevalence of rare variants in both MuRF1 and MuRF2 in HCM patients was higher than that in control subjects (MuRF1 13/594 (2.2%) vs. 1/307 (0.3%), p = 0.04; MuRF2 22/594 (3.7%) vs. 2/307 (0.7%); p = 0.007). Patients with rare variants in MuRF1 or MuRF2 were younger (p = 0.04) and had greater maximum left ventricular wall thickness (p = 0.006) than those without such variants. Mutations in genes encoding sarcomere proteins were present in 19 (55.9%) of the 34 HCM patients with rare variants in MuRF1 and MuRF2. These data strongly supported that rare variants in MuRF1 and MuRF2 are associated with higher penetrance and more severe clinical manifestations of HCM. The findings suggest that dysregulation of the ubiquitin-proteasome system contributes to the pathogenesis of HCM.

Clinical Profile and Prognostic Significance of Atrial Fibrillation in Hypertrophic Cardiomyopathy

Objectives: The clinical outcomes of hypertrophic cardiomyopathy (HCM) are largely unpredictable. This study aimed to investigate the relationship between atrial fibrillation (AF) and its prognostic implications in Chinese patients with HCM. Methods: From 1999 to 2011, 654 unrelated HCM patients were consecutively recruited at Fuwai Hospital. Medical history, including electrocardiographic and echocardiographic data, was analyzed. Results: AF was documented in 158 patients (24%). During follow-up of 4.2 ± 2.8 years, Kaplan-Meier analysis revealed that the presence of AF was associated with an increased risk for all-cause death (p = 0.001), cardiovascular death (p < 0.001), severe heart failure (p < 0.001) and ischemic stroke (p < 0.001). Multivariate analysis identified AF as an independent predictor of stroke-related death (HR 6.71, 95% CI 1.23-38.58, p = 0.03), advanced heart failure (HR 1.83, 95% CI 1.04-3.22, p = 0.04) and ischemic stroke (HR 9.98, 95% CI 4.06-24.53, p < 0.001). Furthermore, enlarged left atrial diameter was positively related to all-cause death (HR 1.09, 95% CI 1.05-1.13, p < 0.001), cardiovascular death (HR 1.08, 95% CI 1.04-1.20, p < 0.001) and development of advanced heart failure (HR 1.05, 95% CI 1.01-1.10, p = 0.01). Conclusions: AF predicts poor outcomes for patients with HCM. Left atrial dilation is also related to an adverse prognosis and provides additional prognostic information.

Malignant effects of multiple rare variants in sarcomere genes on the prognosis of patients with hypertrophic cardiomyopathy.

Although genetic testing has been recommended in patients with hypertrophic cardiomyopathy (HCM) in current clinical practice, its utility in prognostic prediction remains to be ascertained. We assessed the dosage effect of rare variants in sarcomere genes on the long‐term outcomes of HCM.

Autosomal Recessive Transmission of MYBPC3 Mutation Results in Malignant Phenotype of Hypertrophic Cardiomyopathy

Background Hypertrophic cardiomyopathy (HCM) due to mutations in genes encoding sarcomere proteins is most commonly inherited as an autosomal dominant trait. Since nearly 50% of HCM cases occur in the absence of a family history, a recessive inheritance pattern may be involved. Methods A pedigree was identified with suspected autosomal recessive transmission of HCM. Twenty-six HCM-related genes were comprehensively screened for mutations in the proband with targeted second generation sequencing, and the identified mutation was confirmed with bi-directional Sanger sequencing in all family members and 376 healthy controls. Results A novel missense mutation (c.1469G>T, p.Gly490Val) in exon 17 of MYBPC3 was identified. Two siblings with HCM were homozygous for this mutation, whereas other family members were either heterozygous or wild type. Clinical evaluation showed that both homozygotes manifested a typical HCM presentation, but none of others, including 5 adult heterozygous mutation carriers up to 71 years of age, had any clinical evidence of HCM. Conclusions Our data identified a MYBPC3 mutation in HCM, which appeared autosomal recessively inherited in this family. The absence of a family history of clinical HCM may be due to not only a de novo mutation, but also recessive mutations that failed to produce a clinical phenotype in heterozygous family members. Therefore, consideration of recessive mutations leading to HCM is essential for risk stratification and genetic counseling.

Female Sex Is Associated with Worse Prognosis in Patients with Hypertrophic Cardiomyopathy in China

Background Sex plays an important role in the clinical expression and prognosis of various cardiovascular diseases. This study was designed to observe the effects of sex on hypertrophic cardiomyopathy (HCM). Methods and Results A total of 621 unrelated patients with HCM without heart failure (460 males) were enrolled from 1999 to 2011. Compared to male patients, at baseline female patients were older at diagnosis (49.6±17.2 years vs. 46.7±14.4 years, P = 0.033), and had greater frequency of left ventricular outflow tract obstruction (72/161, 44.7% vs. 149/460, 32.4%, P = 0.005). During the average four year follow-up period (range 2–7 years), survival analysis showed that the incidences of mortality from all causes, cardiovascular death and progression to chronic heart failure were greater in women than in men (P = 0.031, 0.040 and 0.012, respectively). After adjustment for multiple factors that may confound survival and cardiac function, female sex remained an independent risk factor for all-cause mortality, cardiovascular death, and chronic heart failure [hazard ratio (HR) 2.19, 95% confidence interval (CI) 1.21–3.95, P = 0.010; HR 2.19, 95% CI 1.17–4.09, P = 0.014; HR 1.73, 95% CI 1.12–2.69, P = 0.014, respectively] in HCM patients. Subgroup analysis revealed that female sex as a risk factor was identified only in patients younger than 50 years old (P = 0.011, 0.011 and 0.009, respectively), but not for those 50 years or older. Conclusion Our results suggest that female sex is associated with worse survival and heart failure in HCM patients. Further studies are required to determine whether female hormones modify the clinical expression and prognosis of HCM.

Myocardial Bridging as a Common Phenotype of Hypertrophic Cardiomyopathy Has No Effect on Prognosis

Background:The prognostic significance of myocardial bridging in hypertrophic cardiomyopathy (HCM) remains controversial. This investigation sought to evaluate the impact of myocardial bridging on prognosis of patients with HCM. Methods:A total of 298 adult patients (73% male, mean age, 53 ± 12 years) with HCM were retrospectively enrolled at Fuwai Hospital from 1999 to 2011. Myocardial bridging was evaluated by coronary angiography. Follow-up data were collected by telephone interviews and mailed questionnaires. Results:Thirty-four (11%, 34/298) patients were determined with myocardial bridging and the middle of left anterior descending artery was the most frequently involved segment (77%, 26/34). Patients with myocardial bridging were younger than those without bridging (48 ± 9 versus 54 ± 12 years, P = 0.001). During the follow-up of 4.2 ± 2.3 years (range, 0.7–12.2 years), the presence of myocardial bridging was not evidently associated with increased risk for all-cause death (P = 0.54), cardiovascular death (P = 0.60), sudden cardiac death (P = 0.53) and deterioration of heart failure (P = 0.84). Conclusions:Myocardial bridging was a relatively common morphological component of HCM but not a predictor for adverse clinical outcomes.