李宁
中国医学科学院阜外医院
AIMS:Two LMNA mutations (R644C and R190W) have been associated with familial and sporadic left ventricular non-compaction (LVNC). However, the mechanisms underlying these associations have not been elucidated.METHODS AND RESULTS:Genomic DNA was isolated from peripheral blood leucocytes and analysed by direct sequencing. Human embryonic kidney 293 cells were transfected with either wild type or mutant LMNA and SCN5A for whole-cell patch-clamp experiment and fluorescence microscopy. Point mutation modeling for mutant LMNA was also performed. One novel LVNC-associated mutation (V445E) in β2 sheet of immunoglobulin (Ig)-like fold was found in the proband and his father. We also found that the peak current of sodium channel was markedly reduced in mutant LMNA compared with WT while the activation, inactivation, and recovery curves were not significantly altered. The mutant lamin A/C were aggregated into multiple highlighted particles. Three β sheets and multiple side chains in Ig-like fold were altered due to the replacement of a valine by glutamic acid.CONCLUSION:Our data associated a novel lamin A/C mutation (V445E) with a sudden death form of familial LVNC. The reduced sodium current in mutant LMNA may account for the advent of malignant ventricular arrhythmias. The altered structures of three β sheets and side chains may partially explain the aggregation of lamin A/C protein subjacent to the nuclear envelope.
Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology 2016
To evaluate the efficacy and safety of Shensong Yangxin (SSYX) in patients with bradycardia arrhythmias, a randomized, double-blind, and placebo-controlled study was conducted. Patients with bradycardia were randomly assigned to receive either SSYX (trial group, n = 115) or placebo (control group, n = 104) for 4 weeks. ECG, 24-hour continuous ECG recording, echocardiography, and hepatic and renal function were evaluated at baseline and after treatment. Results showed that the average heart rate, the fastest heart rate, and the lowest heart rate in the trial group were all significantly higher than those in the control group at the end of treatment (P < 0.05 or 0.01, resp.). Compared with pretreatment, the average heart rate, the fastest heart rate, and the lowest heart rate in the trial group all increased significantly after treatment (P < 0.05 or 0.01, resp.). Both the efficacy and the symptom scores in the trial group were significantly better than those in the control group after treatment (both having P < 0.01). No severe adverse effects were reported. In conclusion, SSYX treatment significantly increased the heart rate in patients with bradycardia without severe side effects. The exact mechanisms remain to be further explored.
Evidence-based complementary and alternative medicine : eCAM 2014
The purpose of this study was to evaluate whether CC-AAbs levels could predict prognosis in CHF patients. A total of 2096 patients with CHF (841 DCM patients and 1255 ICM patients) and 834 control subjects were recruited. CC-AAbs were detected and the relationship between CC-AAbs and patient prognosis was analyzed. During a median follow-up time of 52 months, there were 578 deaths. Of these, sudden cardiac death (SCD) occurred in 102 cases of DCM and 121 cases of ICM. The presence of CC-AAbs in patients was significantly higher than that of controls (both P < 0.001). Multivariate analysis revealed that positive CC-AAbs could predict SCD (HR 3.191, 95% CI 1.598-6.369 for DCM; HR 2.805, 95% CI 1.488-5.288 for ICM) and all-cause mortality (HR 1.733, 95% CI 1.042-2.883 for DCM; HR 2.219, 95% CI 1.461-3.371 for ICM) in CHF patients. A significant association between CC-AAbs and non-SCD (NSCD) was found in ICM patients (HR = 1.887, 95% CI 1.081-3.293). Our results demonstrated that the presence of CC-AAbs was higher in CHF patients versus controls and corresponds to a higher incidence of all-cause death and SCD. Positive CC-AAbs may serve as an independent predictor for SCD and all-cause death in these patients.
Disease markers 2014
The genetic background of early repolarization syndrome (ERS) has not been fully understood. In this study, we identified a missense SCN5A mutation and a polymorphism in a patient with ERS and characterized the functional consequences of the two variants. The functional consequences of mutant channels were investigated with the patch-clamp technique, immunocytochemical studies and real-time PCR. A 19-year-old female proband with recurrent syncope had a documented electrocardiogram with ventricular fibrillation (VF) proceeded by large J waves in leads I, II, III, aVF and V2-V6. Genetic analysis revealed that the patient carried a missense mutation of c.4297 G>C and a synonymous polymorphism of T5457C on the same allele of the SCN5A gene. Patch-clamp experiments demonstrated that the c.4297 G>C mutation significantly reduced the sodium current (INa) density and altered the channel kinetics. Immunocytochemical studies demonstrated that the mutation dramatically inhibited the expression of sodium channels in the cell membrane and in the cytoplasm, although the mRNA levels remained in the normal range. Noteworthy, the reduction in INa density may be partially restored from the co-existence of the T5457C polymorphism on the same allele by the upregulation of mRNA levels. In conclusion, our study indicated that the c.4297 G>C mutation caused the 'loss-of-function' of sodium channels that may account for the clinical phenotype of ERS. The reduction in INa density was due to a decreased number of sodium channels caused by abnormal translation processes. The T5457C polymorphism partially rescued the INa density of the mutant channels by the upregulation of mRNA levels.
International journal of molecular medicine 2013
AIMS:Clinical and animal studies suggest that beta1-adrenergic and M2 muscarinic receptor autoantibodies (beta1-AAbs and M2-AAbs) play important roles in the pathophysiological process of chronic heart failure (CHF). Removal of these autoantibodies improved haemodynamic parameters and left ventricular ejection fraction patients with CHF. The goal of this project is to evaluate whether beta1-AAbs and M2-AAbs predict prognosis and sudden cardiac death (SCD) in CHF.METHODS AND RESULTS:A total of 2062 patients with CHF and 824 control subjects were recruited. Beta1-AAbs and M2-AAbs were detected by the enzyme-linked immunosorbent assay (ELISA) method, and the correlation between these autoantibodies and the prognosis of CHF was analysed. During a median follow-up period of 36 months (0.40 ± 65 months), 379 (21.56%) cases died-164 had dilated cardiomyopathy (DCM) and 215 had ischaemic cardiomyopathy (ICM). Of these, SCD occurred in 69 cases (40.37%) of DCM and in 84 cases (39.07%) of ICM. Positivity for beta1-AAbs in DCM and ICM was significantly higher than for the controls (8.1% and 8.25% v.s 2.2%, both P < 0.01). However, positive M2-AAbs did not show any statistical difference between the three groups. Cox regression analysis revealed that positive beta1-AAbs were associated with higher mortality in CHF and that it predicted SCD for DCM [hazard ratio (HR) 4.51, 95% confidence interval (CI) 2.405-8.471] and ICM (HR 3.749, 95% CI 2.389-5.884) patients, but not non-SCD (NSCD) patients.CONCLUSIONS:The rates of positive beta1-AAbs were higher in CHF patients than in the controls. Positive beta1-AAbs might serve as an independent predictor for SCD in patients with CHF.
European journal of heart failure 2012
AIMS:To investigate the relationship between electrocardiogram (ECG) parameters [J wave, fragmented QRS (fQRS), QTc, the peak-to-end interval of T wave (Tp-Te)], and sudden cardiac death (SCD) in chronic heart failure (CHF).METHODS AND RESULTS:The ECGs of 1570 CHF patients, 572 cases with dilated cardiomyopathy (DCM) and 998 cases with ischaemic cardiomyopathy (ICM) were analysed with the endpoint being an SCD or non-SCD (NSCD). During a median follow-up period of 36 months (0.40-65 months), 438 (27.89%) patients died, of which 158 (35.84%) were SCD. Overall, the occurrence of J wave, fQRS, and long Tp-Te were greater in SCD patients than that of NSCD patients (all P< 0.01). For DCM cases, more SCD patients had J waves observed in the inferior leads than that in the NSCD group (26.78 vs. 13.07%, P<0.001). However, ICM cases with SCD did have more fQRS in the inferior leads than that with NSCD (42.16 vs. 26.67%, P= 0.01). After adjusting for other risk factors, Cox regression analysis revealed that presence of J wave or fQRS in the inferior leads predicted a higher risk for SCD in DCM [hazard ratio (HR), 4.095; 95% confidence interval (CI), 2.132-7.863] and ICM (HR, 2.714; 95% CI, 1.809-4.072) patients. A left ventricular ejection fraction ≤ 30% also predicted SCD and NSCD in DCM and ICM patients. In contrast, the predictive value of QTc and Tp-Te for SCD was not significant.CONCLUSIONS:Presence of J wave or fQRS in the inferior leads predicted higher risk of SCD in DCM and ICM patients and might serve as independent predictors for SCD in patients with CHF.
Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology 2012
Ca2+ cycling plays a critical role in heart failure and lethal arrhythmias. As susceptibility to sudden cardiac death is considered to be a heritable trait in general population, we have therefore investigated whether potentially functional variants of genes encoding RyR2 (ryanodine receptor 2) and the L-type Ca2+ channel are related to the risk of ventricular arrhythmias and sudden cardiac death in CHF (chronic heart failure) in a case-control study. We found that the A allele of rs3766871 in RYR2 was associated with an increased risk of ventricular arrhythmias in patients with CHF {odds ratio, 1.66 [95% CI (confidence interval), 1.21-2.26]; P=0.002}. During a median follow-up period of 32 months in 1058 (85.0%) patients, 296 (28.0%) patients died from heart failure, of whom 141 (47.6%) had sudden cardiac death. After adjustment for age, gender and suspected risk factors, patients carrying the A allele of rs3766871 had an increased risk of cardiac death {HR (hazard ratio), 1.53 [95% CI, 1.11-2.12]; P=0.010} and sudden cardiac death [HR, 1.92 (95% CI, 1.25-2.94); P=0.003]. Patients carrying the A allele of rs790896 in RYR2 had a reduced risk of sudden cardiac death [HR, 0.65 (95% CI, 0.45-0.92); P=0.015]. In conclusion, the A allele of rs3766871 in RYR2 not only associates with ventricular arrhythmias, but also serves as an independent predictor of sudden cardiac death, and the A allele of rs790896 in RYR2 is a protective factor against sudden cardiac death in patients with CHF.
Clinical science (London, England : 1979) 2010
BACKGROUND:Imbalance of the sympathetic nervous system was involved in the pathogenesis of idiopathic ventricular outflow-tract tachycardia (IVOT). We aimed to investigate whether the major genetic variants in β(1)- and β(2)-adrenoceptors and GNB3 C825T were associated with IVOT and verapamil sensitive idiopathic left ventricular tachycardia (ILVT).METHODS:Patients with IVOT and ILVT from December 2005 to December 2007 were consecutively enrolled into this study. Controls were randomly selected from the community-based inhabitants. Five genetic variants, Ser49Gly and Gly389Arg in the β(1)-adrenoceptor, Arg16Gly and Gln27Glu in the β(2)-adrenoceptor and GNB3 C825T, were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis.RESULTS:A total of 227 patients with IVOT and 110 patients with ILVT were included. Genotyping revealed that the 16Gly allele of Arg16Gly variant of β(2)-adrenoceptor was associated with a higher risk of IVOT (OR: 1.40, 95%CI: 1.12 - 1.75, P = 0.003 in the addictive model and OR: 1.62, 95%CI: 1.14 - 2.31, P = 0.007 in the dominant model). Patients with Gly16Gln27 haplotype also had a higher risk of IVOT (OR: 1.38, 95%CI: 1.11 - 1.73, P = 0.012). Other four variants, including Ser49Gly and Arg389Gly in β(1)-adrenoceptor, Gln27Glu in β(2)-adrenoceptor and GNB3 C825T, did not differ between patients with IVOT and controls. In patients with ILVT, no significant difference was found in these five variants compared with controls.CONCLUSIONS:Arg16Gly in β(2)-adrenoceptor is significantly associated with IVOT in Chinese Han population. Major genetic variants in β(1)- and β(2)-adrenoceptor and GNB3 C825T may not be associated with ILVT. These data suggest a different arrhythmogenic mechanism in IVOT and ILVT.
Chinese medical journal 2010
BACKGROUND:Pharmacologic restoration of the trafficking defects of HERG missense mutations has been documented. However, whether correction of HERG nonsense mutations is possible is unknown.OBJECTIVE:The purpose of this study was to investigate the effect of aminoglycoside antibiotics on the expression of nonsense mutants expected to produce truncated HERG channels.METHODS:HERG channel and mutant currents were recorded by whole-cell patch clamp techniques. Pharmacologic rescue was applied by culturing the cells in 400 microg/mL G-418 or gentamicin for 24 hours.RESULTS:Current densities were significantly reduced in cells expressing R1014X and W927X mutants compared to those of cells expressing wild-type (WT) HERG. R863X and E698X mutants failed to generate any typical HERG currents. Mean peak tail current density of R1014X mutant was significantly lower than that of WT (3.9 +/- 1.4 pA/pF, n = 8, vs 47.8 +/- 6.3 pA/pF, n = 12, P <.05) and increased to 12.7 +/- 3.3 pA/pF (n = 7, P <.05) and 18.3 +/- 3.7 pA/pF (n = 8, P <.05) after G-418 and gentamicin treatment. The voltage dependence of activation of R1014X was also restored after drug treatment. Furthermore, expression of full-length proteins for R1014X induced by drugs was detected by western blot and confocal imaging. Similar results were observed in W927X. For R863X and E698X, however, gentamicin treatment had no effect. In the cells cotransfected with WT/R1014X, gentamicin and G-418 demonstrated different results: gentamicin, but not G-418, increased the current density by 2.2-fold (n = 12, P <.05).CONCLUSION:The study findings provide proof of principle that interventions designed to read through premature stop mutations may at least partially reverse the LQT2 phenotype in vitro.
Heart rhythm 2009
OBJECTIVE:To investigate the effects of dry powder of ShenSongYangXin capsule on sodium current (I(Na)) and L-type calcium current (I(Ca, L)) in ventricular myocytes.METHODS:Ventricular myocytes were isolated from guinea pig. Solution of the dry powder of ShenSongYangXin capsule of the concentrations of 1%, 0.5%, and 0.25% was added into the suspension of the myocytes. Whole cell patch-clamp technique was used to detect the I(Na) and I(Ca, L) in the ventricular myocytes.RESULT:ShenSongYangXin decreased the peak I(Na) from 27.2 +/- 5.4 (pA/pF) to 14.9 +/- 2.8 (pA/pF), with a decrease rate of 44.8% +/- 7.7% (n = 5, P < 0.05). The solution of dry powder of ShenSongYangXin of the concentrations of 1%, 0.5%, and 0.25% decreased the peak L-type calcium channel current (I(ca, L)) significantly in a concentration dependent manner with the reduction rates of 50.7% +/- 5.6%, 44.8% +/- 6.5%, and 19.2% +/- 1.1% respectively (n = 5, all P < 0.05). ShenSongYangXin shifted up both the I approximately 1V curve of I(Na) and that of I(Ca, L), while their active, peak and reverse potentials didn't change.CONCLUSION:ShenSongYangXin blocks both I(Na) and I(Ca, L), which may contributes to some of its antiarrhythmic effect.
Zhonghua yi xue za zhi 2007
