Effects of GRK5 and ADRB1 polymorphisms influence on systolic heart failure.

BACKGROUND: G-protein receptor kinase 5 (GRK5) Gln41 > Leu and ß1-adrenergic receptor (ADRB1) Arg389 > Gly polymorphisms presented the different distribution of genotype frequencies between Caucasian American and African American, and produced the difference in ß-blocker treatment effect among them with systolic heart failure (SHF). OBJECTIVE: This study sought to identify the distributed characteristics of these variant genotypes in Chinese population, and influence of GRK5 and ADRB1 polymorphisms on SHF morbidity and ß-blocker treatment effect in patients with SHF. METHODS: This study was based on cross-sectional survey data. 1794 and 1718 subjects' ADRB1 and GRK5 gene sequencing (sanger method) data were achieved respectively. Blood samples collection, clinical laboratory detection, electrocardiogram and echocardiography examinations were performed. Medication usage was confirmed at in-hospital visits or the questionnaire by personal interview. RESULTS: GRK5 Leu41Leu genotype was not found in our Chinese population. In non-SHF population, allele frequencies of GRK5 Gln41 and Leu41 were 2782 (0.992) and 22 (0.008) (Hardy-Weinberg equilibrium test χ(2) = 0.088, P = 0.767), and allele frequencies of ADRB1 Arg389 and Gly389 were 2127 (0.715) and 849 (0.285) (χ(2) = 0.272, P = 0.602). In SHF patients, allele frequencies of Gln41 and Leu41 were 446 (0.991) and 4 (0.009) (χ(2) = 0.018, P = 0.893), and allele frequencies of Arg389 and Gly389 were 331 (0.726) and 125 (0.274) (χ(2) = 1.892, P = 0.169). Further in logistic regression model, these ADRB1 and GRK5 variants were not significantly independently associated with the risk of SHF morbidity. Those carrying genotype ADRB1 Gly389Gly did not reduce significantly the risk of SHF morbidity after ß-blocker therapy. CONCLUSIONS: GRK5 Leu41Leu genotype was not found in our Chinese population, neither ADRB1 nor GRK5 variants presented independently associated with the risk of SHF morbidity, most ADRB1 and GRK5 polymorphisms did decrease significantly the risk of SHF morbidity after ß-blocker therapy except for those carrying genotype ADRB1 Gly389Gly.

Pressure overload-induced cardiac hypertrophy response requires janus kinase 2-histone deacetylase 2 signaling.

Pressure overload induces cardiac hypertrophy through activation of Janus kinase 2 (Jak2), however, the underlying mechanisms remain largely unknown. In the current study, we tested whether histone deacetylase 2 (HDAC2) was involved in the process. We found that angiotensin II (Ang-II)-induced re-expression of fetal genes (Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP)) in cultured cardiomyocytes was prevented by the Jak2 inhibitor AG-490 and HDAC2 inhibitor Trichostatin-A (TSA), or by Jak2/HDAC2 siRNA knockdown. On the other hand, myocardial cells with Jak2 or HDAC2 over-expression were hyper-sensitive to Ang-II. In vivo, pressure overload by transverse aorta binding (AB) induced a significant cardiac hypertrophic response as well as re-expression of ANP and BNP in mice heart, which were markedly reduced by AG-490 and TSA. Significantly, AG-490, the Jak2 inhibitor, largely suppressed pressure overload-/Ang-II-induced HDAC2 nuclear exportation in vivo and in vitro. Meanwhile, TSA or HDAC2 siRNA knockdown reduced Ang-II-induced ANP/BNP expression in Jak2 over-expressed H9c2 cardiomyocytes. Together, these results suggest that HDAC2 might be a downstream effector of Jak2 to mediate cardiac hypertrophic response by pressure overload or Ang-II.

MicroRNA-34a regulates cardiac fibrosis after myocardial infarction by targeting Smad4.

BACKGROUND: Although few microRNAs (miRNAs) have been involved in the regulation of post-ischemic cardiac fibrosis, the exact effect and underlying mechanism of miRNAs in cardiac fibrosis remains unclear. Here, we sought to investigate whether microRNA-34 (miR-34) plays a role in the pathogenic development of myocardial fibrosis. METHODS: The myocardial infarction (MI) mice model was induced and cardiac fibroblasts were cultured. Histological analyses, quantitative real-time polymerase chain reaction and Western blotting analysis were used. RESULTS: We found that the miR-34 cluster, especially miR-34a, was upregulated in the MI heart. In vivo, inhibition of miR-34a reduces the severity of experimental cardiac fibrosis in mice. TGF-ß1 increased miR-34a expression in cardiac fibroblasts. Overexpressing miR-34a levels increased the profibrogenic activity of TGF-ß1 in cardiac fibroblast, whereas inhibition miR-34a levels weakened the activity. Finally, we showed that miR-34a's underlying mechanism during cardiac fibrosis occurs through the targeting of Smad4 expression. CONCLUSIONS: Our findings provide evidence that miR-34a plays a critical role in the progression of cardiac tissue fibrosis by directly targeting Smad4, which suggests that miR-34a may be new marker for cardiac fibrosis progression and that inhibition of miR-34a may be a promising strategy in the treatment of cardiac fibrosis.

NKX2-6 mutation predisposes to familial atrial fibrillation.

Atrial fibrillation (AF) is the most common form of sustained cardiac arrhythmia and is associated with substantially increased morbidity and mortality rates. Aggregating evidence demonstrates that genetic defects are involved in the pathogenesis of AF and a number of AF-associated genes have been identified. Nevertheless, AF is a genetically heterogeneous disorder and the genetic components underpinning AF in an overwhelming majority of patients remain unclear. In this study, the entire coding exons and splice junction sites of the NK2 homeobox 6 (NKX2-6) gene, which encodes a homeodomain transcription factor important for cardiovascular development, were sequenced in 150 unrelated patients with lone AF, and a novel heterozygous NKX2-6 mutation, p.Q175H, was identified in an index patient. Genetic analysis of the available family members of the mutation carrier revealed that the mutation co-segregated with AF transmitted in an autosomal dominant pattern. The missense mutation was absent in the 200 unrelated ethnically matched healthy individuals used as controls and the altered amino acid was completely conserved evolutionarily among species. Due to unknown transcriptional targets of NKX2-6, the functional characteristics of the mutation as regards transcriptional activity were analyzed using NKX2-5 as a surrogate. Alignment between human NKX2-6 and NKX2-5 proteins displayed that the Q175H-mutant NKX2-6 was equivalent to the Q181H-mutant NKX2-5, and the introduction of Q181H into NKX2-5 significantly decreased its transcriptional activity at the atrial natriuretic factor promoter. The present study firstly associates genetically defective NKX2-6 with enhanced susceptibility to AF, providing novel insight into the molecular mechanisms underlying AF and suggesting potential strategies for the antenatal prophylaxis and personalized treatment of AF.

Growth differentiation factor 15, ischemia modified albumin and pregnancy-associated plasma protein A in patients with coronary artery disease.

BACKGROUND: Growth differentiation factor 15 (GDF-15), ischemia modified albumin (IMA) might aid in the early diagnosis and risk stratification of patients with coronary artery disease (CAD), while pregnancy associated plasma protein-A (PAPP-A) can serve as a useful marker of vulnerable plaques and acute coronary syndrome (ACS). We sought to determine serum levels of GDF-15, IMA, PAPP-A and evaluate their diagnostic value in different types of CAD. METHODS: We detected serum levels of GDF-15, IMA and PAPP-A in 348 patients with CAD and 205 controls. Levels of high-sensitivity C reactive protein, creatine kinase isoenzyme MB, and high-sensitivity cardiac troponin-T, which represent biomarkers of inflammation, damage or necrosis, were also evaluated. RESULTS: There were significant differences of GDF-15, IMA and PAPP-A in patients with CAD compared with the controls, where GDF-15 seemed to be associated with severity of CAD. GDF-15 demonstrated a sensitivity of 84.0% and specificity of 84.8% for diagnosis of UAP, while the negative predictive value was 87.4%. The sensitivity and specificity, negative predictive value of IMA in the diagnosis of UAP were 70.0%, 69.5%, and 70.0%, respectively. PAPP-A had the lowest sensitivity and negative predictive value compared with other markers. CONCLUSIONS: GDF-15 demonstrated a significant improvement in earlier prediction and assessment of overall patient risk of UAP comparing to IMA and PAPP-A.

Percutaneous closure of postinfarct muscular ventricular septal defects: a multicenter study in China.

BACKGROUND: Surgical repair is an effective method to treat ventricular septal defect (VSD) complicating acute myocardial infarction (AMI). However, the mortality rate remains high. This study was designed to assess the immediate and mid-term results of transcatheter closure of postinfarct muscular VSDs. METHODS: Data were retrospectively collected from 42 AMI patients who underwent attempted transcatheter VSD closure between 2008 and 2012 in seven heart centers of China. RESULTS: Nine patients underwent emergent VSD closure in the acute phase (within two weeks from VSD) while the others underwent elective closure. The time between VSD occurrence and closure in emergency group and elective group was 7.7 ± 2.3 days and 35 ± 14.5 days, respectively (p<0.01). The percentage of procedure success in the emergency group and elective group was 77.8% (7/9) and 97% (32/33), respectively (p=0.048). The hospital mortality was higher for emergent closure in comparison to elective closure (66.7% vs. 6.1%, p<0.01). During a median follow-up of 25 months (0-58 months), two patients died at 8 and 29 months, respectively, and no serious complications occurred in other patients. CONCLUSION: Interventional postinfarct VSD closure is a safe and effective approach that can be performed with a high procedural success rate, with favorable outcomes if it can be undertaken >14 days postinfarct.

A novel PITX2c loss-of-function mutation associated with familial atrial fibrillation.

Atrial fibrillation (AF) represents the most prevalent form of sustained cardiac arrhythmia and contributes substantially to cardiovascular morbidity and mortality. Aggregating evidence demonstrates that genetic risk factors play an important role in the pathogenesis of AF. However, AF is a genetically heterogeneous disease and the genetic defects responsible for AF in an overwhelming majority of patients remain unclear. In the present study, the whole coding region and splice junction sites of the PITX2c gene, which encodes a paired-like homeobox transcription factor essential for normal cardiovascular development, were sequenced in 160 unrelated patients with lone AF, and a novel heterozygous mutation, c.349C > T equivalent to p.P117S, was identified in a patient with positive family history of AF. The missense mutation, which co-segregated with AF in the family with complete penetrance and was absent in 700 unrelated ethnically matched healthy individuals, altered the amino acid completely conserved evolutionarily across species and was predicted to be pathogenic by MutationTaster and PolyPhen-2. Biological assays revealed that the mutant PITX2c protein was associated with significantly decreased transcriptional activity when compared with its wild-type counterpart. The findings implicate PITX2c loss-of-function mutation in familial AF for the first time, providing novel insight into the molecular pathology of AF.

Modified clopidogrel loading dose according to platelet reactivity monitoring in patients carrying ABCB1 variant alleles in patients with clopidogrel resistance.

OBJECTIVES: The aim of the present study was to investigate the impact of a adjusted clopidogrel loading dose (LD) according to platelet reactivity index in carriers of ABCB1 mutant allele undergoing percutaneous coronary intervention (PCI). METHODS: All patients met the inclusion criteria were recruited in the present study. Platelet reactivity was measured using the vasodilator-stimulated phosphoprotein (VASP) index. High treatment platelet reactivity (HTPR) was determined by a cut-off value of >50%. The genetic polymorphism of ABCB1 was determined by allele-specific polymerase chain reaction (PCR). In patients carrying ABCB1 and HTPR after a first 300-mg LD of clopidogrel, dose adjustment was performed by using up to 3 additional 300-mg LDs to obtain a VASP index<50%. The rate of major adverse cardiovascular events (MACE) and major or minor bleeding in one month were recorded. RESULTS: 536 patients were included in the present study. One hundred seventy-two patients (32%) carried ABCB1 mutant allele (11 homozygotes [2%] and 161 heterozygotes [30%]). The VASP index in these patients was significantly higher than in homozygotic patients for the wild allele (65.5±13.8% vs. 47.6±21.8%; p<0.001). Of the 172 ABCB1 mutant allele carriers, 130 were considered to have HTPR. After a second clopidogrel LD, the VASP index was significantly decreased in these patients (66.9±12.8% vs.50.2±18.3%; <0.001). Finally, dose adjustment according to platelet reactivity monitoring enabled 88% of ABCB1 mutant allele carriers and 91% of wild allele carriers exhibiting HTPR to reach a VASP index<50%. The rate of MACE and major or minor bleeding in one-month follow-up between the wild allele carriers and the mutant allele carriers didn't differentiate significantly. CONCLUSIONS: Increased and adjusted clopidogrel loading dose according to platelet reactivity monitoring attenuated clopidogrel resistance in carriers of ABCB1 mutant allele.

Reference value of brachial-ankle pulse wave velocity for the eastern Chinese population and potential influencing factors

The present study was conducted to obtain reference values for brachial-ankle pulse wave velocity (baPWV) and to evaluate influencing factors of baPWV according to gender. Using automatic devices, baPWV was measured simultaneously in 2095 subjects. A total of 647 healthy subjects, none of whom presented atherosclerotic risk factors, were analyzed in the present study. Two different statistical methods were used to obtain reference values for baPWV according to subject gender and age. The association between baPWV value and gender, as well as other features, were analyzed. For male subjects, multiple stepwise analysis showed that age, systolic blood pressure (SBP), heart rate (HR), and plasma levels of triglycerides (TG) were independent predictors of baPWV. For female subjects, age, SBP, HR, and plasma levels of uric acid (UA) were independent predictors of baPWV. In male subjects, the upper limits of baPWV values were 1497.43/1425.00, 1518.67/1513.25, 1715.97/1726.50, 1925.20/1971.90, and 2310.18/2115.00 cm/s, obtained using two different statistical methods for the age ranges of 30-39, 40-49, 50-59, 60-69, and 70 and older, respectively. For females, the upper limits of baPWV values were 1426.70/1411.13, 1559.15/1498.95, 1733.50/1739.00, 1958.63/1973.78, and 2720.80/2577.00 cm/s for the age ranges of 30-39, 40-49, 50-59, 60-69, and 70 and older, respectively. Aging is the most important influencing factor for baPWV value and its effect is more prominent in females. The reference values of baPWV according to age and gender may be useful for the clinical diagnosis and preventive therapy of cardiovascular diseases.

Reference value of brachial-ankle pulse wave velocity for the eastern Chinese population and potential influencing factors.

The present study was conducted to obtain reference values for brachial-ankle pulse wave velocity (baPWV) and to evaluate influencing factors of baPWV according to gender. Using automatic devices, baPWV was measured simultaneously in 2095 subjects. A total of 647 healthy subjects, none of whom presented atherosclerotic risk factors, were analyzed in the present study. Two different statistical methods were used to obtain reference values for baPWV according to subject gender and age. The association between baPWV value and gender, as well as other features, were analyzed. For male subjects, multiple stepwise analysis showed that age, systolic blood pressure (SBP), heart rate (HR), and plasma levels of triglycerides (TG) were independent predictors of baPWV. For female subjects, age, SBP, HR, and plasma levels of uric acid (UA) were independent predictors of baPWV. In male subjects, the upper limits of baPWV values were 1497.43/1425.00, 1518.67/1513.25, 1715.97/1726.50, 1925.20/1971.90, and 2310.18/2115.00 cm/s, obtained using two different statistical methods for the age ranges of 30-39, 40-49, 50-59, 60-69, and 70 and older, respectively. For females, the upper limits of baPWV values were 1426.70/1411.13, 1559.15/1498.95, 1733.50/1739.00, 1958.63/1973.78, and 2720.80/2577.00 cm/s for the age ranges of 30-39, 40-49, 50-59, 60-69, and 70 and older, respectively. Aging is the most important influencing factor for baPWV value and its effect is more prominent in females. The reference values of baPWV according to age and gender may be useful for the clinical diagnosis and preventive therapy of cardiovascular diseases.

Modifying clopidogrel maintenance doses according to vasodilator-stimulated phosphoprotein phosphorylation index improves clinical outcome in patients with clopidogrel resistance.

BACKGROUND: Despite dual antiplatelet therapy, the rate of major adverse cardiovascular events (MACE) after percutaneous coronary intervention (PCI) remains high. Ex vivo tests of clopidogrel resistance can predict MACE after PCI. The purpose of this study is to evaluate the clinical impact of adjusting phosphorylation analysis in patients with clopidogrel resistance undergoing PCI. HYPOTHESIS: We hypothesized that VASP-guided clopidogrel maintenance doses, compared to fixed doses, improved clinical outcome. METHODS: This monocentric, prospective, randomized study was performed on 306 patients undergoing PCI. Patients were randomized to a control group (n = 156) and to a vasodilator-stimulated phosphoprotein (VASP)-guided group (n = 150). In the VASP-guided group, patients received adjusted maintenance doses of clopidogrel to obtain platelet reactivity index (PRI) of <50% during 1 year after PCI. The primary endpoint was the rate of MACE. The secondary endpoints were major and minor bleeding. RESULTS: All patients completed the PCI procedure and 298 patients completed follow-up. The control and VASP-guided groups had similar demographic, clinical, and angiographic characteristics. In the VASP-guided group, PRI was significantly decreased (from 72.1% ± 11.4% to 27.7% ± 8.4%; P = 0.001) in 128 patients (87.1% of all participants). During the 1-year follow-up, 14 MACEs were recorded in the VASP-guided group and 30 MACEs were recorded in the control group (9.3% vs 20.4%, respectively; P = 0.008). There was no difference in the rate of major and minor bleeding in the VASP-guided group compared with the control group (12.9% vs 16.6%; P = 0.06). CONCLUSIONS: Modifying clopidogrel maintenance doses according to platelet reactivity monitoring decreases the rate of MACE after PCI without increasing bleeding in patients with clopidogrel resistance during 1-year follow-up.

Relationship of arterial stiffness and early mild diastolic heart failure in general middle and aged population.

AIMS: The brachial-ankle pulse wave velocity (baPWV) has been recognized as a marker that reflects arterial stiffness. We conducted an investigation to evaluate whether baPWV is independently associated with early mild diastolic heart failure (DHF) in a general middle and aged population. METHODS AND RESULTS: From 1 July 2009 until 31 August 2009, we investigated 2095 subjects for the relevant factors of heart failure in the Lujiazui Community, Shanghai. The baPWV, echocardiography, and blood sampling were performed in the morning after a 12 h overnight fast. A total of 1929 subjects had the complete data, including questionnaire, age, gender, baPWV, brain natriuretic peptide, and E/A ratio. Early mild DHF was defined as a left ventricular ejection fraction >50%, E/A ratio <0.8, and E/E' ≤ 8; finally, 482 subjects with early mild DHF and 1282 subjects with non-DHF entered into analysis. Among 1764 subjects, 31.6% of the subjects were male (average age was 58.0 ± 12.3), 35.8% of the subjects had hypertension, the average body mass index (BMI) was 24.2 ± 3.3 kg/m(2), baPWV was 1513.0 (1329.1, 1763.5) cm/s, and the baPWV was significantly correlated with the E/A ratio (r = -0.39, P < 0.01). There was a difference of the baPWV [1456.0 (1295.3, 1698.3) vs. 1670.5 (1465.6, 1910.8) cm/s] between the non-DHF group and the early mild DHF group (P < 0.01). Multiple logistic-regression analyses demonstrated that age, male gender, BMI, baPWV, posterior left ventricular wall thickness (PVWT), interventricular septal thickness (IVST), E/E' ratio, left ventricular mass index (LVMI), systolic blood pressure (≥140 mmHg), and diastolic blood pressure (≥90 mmHg) were independently correlated with early mild DHF. CONCLUSIONS: The increased arterial stiffness is associated with early mild DHF in a general middle and aged population independently of age, male gender, BMI, PVWT, IVST, E/E' ratio, LVMI, and high blood pressure. The non-invasive techniques described may allow serial measurements to be made over time to monitor baPWV changes in arteries provided the introduction of anti-arteriosclerosis therapy.