Research progress of the correlation between genotype and phenotype in hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant genetic disease characterized by left ventricular hypertrophy with prevalence of 1/500-1/200. Up to now, 1500 mutations in more than 30 genes have been found to be related to the disease. Pathogenic gene mutations together with polymorphisms of modifying genes and environmental factors play various roles in the disease processes, resulting in phenotypic heterogeneity of the disease, ranging from no symptoms to sudden cardiac death. The pathological phenotypes of HCM mainly include cardiomyocyte hypertrophy, disordered array, fibrosis, myocardial ischemia, and others. In recent years, many research efforts have been devoted to exploring the influence of HCM genotype on phenotype, and development of treatment methods based on genetics. This article focuses on the correction between HCM genotype and phenotype and summarizes the research progresses on HCM in terms of pathogenic genes, pathogenesis, associated modification factors and treatment methods, thereby providing insights on the future research and development on the genetics of HCM.

The Value of the CHADS2 and CHA2DS2-VASc Score for Predicting the Prognosis in Lacunar Stroke with or without Atrial Fibrillation Patients.

BACKGROUND: The CHADS2 and CHA2DS2-VASc scoring systems have been proved efficacy to stratify stroke and thromboembolism risk in patients with atrial fibrillation (AF). Whether CHADS2 and CHA2DS2-VASc score has predictive value for the prognosis in lacunar stroke (LS) patients remains unclear. METHODS: A total of 763 consecutive patients with LS (mean age: 66 ± 12 years; 464 male) were enrolled in this study between January 2013 and December 2014. Patients were divided into LS without AF (LS; n = 679) and LS with AF (LS-AF; n = 84) groups. Measures of performance for the risk scores were evaluated at predicting mortality and restroke in LS-AF and LS without AF patients. All patients were evaluated with respect to clinical features and in-hospital clinical results. RESULTS: During the mean follow-up period of 20 ± 5.8 months, 29 patients (3.8%) experienced all-cause death, 105 patients (13.8%) experienced recurrence of ischemic stroke. Multivariate analysis revealed that CHADS2 and CHA2DS2-VASc score were independently associated with all-cause death (all P < .05). On receiver operating characteristic curve analysis, area under the curve (AUC) for CHADS2 score was .942 with a similar accuracy of the CHA2DS2-VASc score (AUC: .908) in predicting mortality in LS-AF patients. Kaplan-Meier curves were conducted according to the cut-off value of CHA2DS2-VASc score. When CHADS2 score greater than or equal to 4 point or CHA2DS2-VASc score greater than or equal to 5 point, the mortality in LS-AF patients was significantly higher compared with those CHADS2 score less than 4 point or CHA2DS2-VASc score less than 5 point. However, after adjusting for clinical covariates, CHADS2 and CHA2DS2-VASc score could not predict both mortality and restroke in LS without AF patients. CONCLUSIONS: The CHADS2 and CHA2DS2-VASc score have excellent predictive value for mortality in LS-AF patients but could not predict both mortality and restroke in LS without AF patients.

Myeloid differentiation protein 1 protected myocardial function against high-fat stimulation induced pathological remodelling.

Myeloid differentiation 1 (MD-1) is a secreted protein that regulates the immune response of B cell through interacting with radioprotective 105 (RP105). Disrupted immune response may contribute to the development of cardiac diseases, while the roles of MD-1 remain elusive. Our studies aimed to explore the functions and molecular mechanisms of MD-1 in obesity-induced cardiomyopathy. H9C2 myocardial cells were treated with free fatty acid (FFA) containing palmitic acid and oleic acid to challenge high-fat stimulation and adenoviruses harbouring human MD-1 coding sequences or shRNA for MD-1 overexpression or knockdown in vitro. MD-1 overexpression or knockdown transgenic mice were generated to assess the effects of MD-1 on high-fat diet (HD) induced cardiomyopathy in vivo. Our results showed that MD-1 was down-regulated in H9C2 cells exposed to FFA stimulation for 48 hours and in obesity mice induced by HD for 20 weeks. Both in vivo and in vitro, silencing of MD-1 accelerated myocardial function injury induced by HD stimulation through increased cardiac hypertrophy and fibrosis, while overexpression of MD-1 alleviated the effects of HD by inhibiting the process of cardiac remodelling. Moreover, the MAPK and NF-κB pathways were overactivated in MD-1 deficient mice and H9C2 cells after high-fat treatment. Inhibition of MAPK and NF-κB pathways played a cardioprotective role against the adverse effects of MD-1 silencing on high-fat stimulation induced pathological remodelling. In conclusion, MD-1 protected myocardial function against high-fat stimulation induced cardiac pathological remodelling through negative regulation for MAPK/NF-κB signalling pathways, providing feasible strategies for obesity cardiomyopathy.

A novel approach to select differential pathways associated with hypertrophic cardiomyopathy based on gene co­expression analysis.

The present study was designed to develop a novel method for identifying significant pathways associated with human hypertrophic cardiomyopathy (HCM), based on gene co­expression analysis. The microarray dataset associated with HCM (E­GEOD­36961) was obtained from the European Molecular Biology Laboratory­European Bioinformatics Institute database. Informative pathways were selected based on the Reactome pathway database and screening treatments. An empirical Bayes method was utilized to construct co­expression networks for informative pathways, and a weight value was assigned to each pathway. Differential pathways were extracted based on weight threshold, which was calculated using a random model. In order to assess whether the co­expression method was feasible, it was compared with traditional pathway enrichment analysis of differentially expressed genes, which were identified using the significance analysis of microarrays package. A total of 1,074 informative pathways were screened out for subsequent investigations and their weight values were also obtained. According to the threshold of weight value of 0.01057, 447 differential pathways, including folding of actin by chaperonin containing T­complex protein 1 (CCT)/T­complex protein 1 ring complex (TRiC), purine ribonucleoside monophosphate biosynthesis and ubiquinol biosynthesis, were obtained. Compared with traditional pathway enrichment analysis, the number of pathways obtained from the co­expression approach was increased. The results of the present study demonstrated that this method may be useful to predict marker pathways for HCM. The pathways of folding of actin by CCT/TRiC and purine ribonucleoside monophosphate biosynthesis may provide evidence of the underlying molecular mechanisms of HCM, and offer novel therapeutic directions for HCM.

Attractors of hypertrophic cardiomyopathy using maximal cliques and attract methods.

BACKGROUND: Our study was designed to identify the differential attractor modules related with hypertrophic cardiomyopathy (HCM) by integrating clustering-based on maximal cliques algorithm and Attract method. METHODS: We firstly recruited the HCM-related microarray data from ArrayExpress database. Next, protein-protein interaction (PPI) networks of normal and HCM were constructed and re-weighted using spearman correlation coefficient (SCC). Then, maximal cliques were found from the PPI networks through the clustering-based on maximal cliques approach. Afterwards, highly overlapped cliques were eliminated or merged according to the interconnectivity, and then modules were obtained. Subsequently, we used Attract method to identify differential attractor modules, following by the pathway enrichment analyses for genes in differential attractor modules. RESULTS: After removing the cliques with nodes less than or equal to 4, 926 and 1118 maximal cliques in normal and HCM PPI networks were obtained for module analysis. Then, we obtained 32 and 55 modules from the PPI networks of normal and HCM, respectively. By comparing with normal condition, there were 5 module pairs with the same or similar gene composition. Significantly, based on attract method, we found that these 5 modules were differential attractors. Pathway enrichment analyses indicated that proteasome, ribosome and oxidative phosphorylation were the significant pathways. CONCLUSIONS: Proteasome, ribosome and oxidative phosphorylation might play pathophysiological roles in HCM.

[KCNQ1 mutation in patients with lone atrial fibrillation].

OBJECTIVE: Recent studies suggest that mutation of the slow delayed rectifier potassium channel [I(Ks)] contributes to familial atrial fibrillation (FAF). In the current study, we explored the potential association between KCNQ1 polymorphism with lone AF (LAF). METHODS: Clinical data and blood samples were collected from 95 Han Chinese patients with LAF and matched healthy controls. Variants of the KCNQ1 gene were identified using single-strand conformational polymorphism (SSCP) analysis. A case-control association study in KCNQ1 identified four known single-nucleotide polymorphisms (SNPs) during SSCP screening of the 95 LAF patients and 190 healthy controls. RESULTS: Three new variations were identified in KCNQ1 from 95 sporadic LAF including 1 in 5'UTR(c.-22T > C), 1 in exon9 synonymous mutation (c.1008C > T) and 1 in intron region (c.1590 + 31A > T). These variations were heterozygous and not presented in 190 healthy controls. Highly significant difference was detected between LAF group and control groups in rs760419 polymorphism. Logistic regression revealed that rs760419 was independent risk factor for LAF(OR = 2.056, P = 0.001). CONCLUSIONS: KCNQ1 mutation is associated with LAF and rs760419 polymorphism is a susceptible marker for LAF.