Maternal MTHFR C677T polymorphism and congenital heart defect risk in the Chinese Han population: a meta-analysis.

Numerous studies have evaluated the association between the maternal C677T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene and congenital heart defect (CHD) risk in the Chinese Han population. However, the specific association is still controversial. Six separate studies with 1089 subjects in the Chinese Han population on the relationship between the C677T polymorphism and CHDs were analyzed by meta-analysis, upon database search. The fixed-effect model or random-effect model was selected to calculate the pooled odds ratio (ORs) and its corresponding 95% confidence interval (95%CI) when appropriate. The Begg test was used to measure publication bias. Sensitivity analyses were performed to insure authenticity of the outcome. Meta-analysis of the results showed significant associations between the maternal C677T polymorphism and CHD risk (CC vs TT: OR = 0.65, 95%CI = 0.44-0.96). Limiting the analysis to the studies with controls in the Hardy-Weinberg equilibrium and the results indicate that the meta-analysis was statistically significant. Results of Begg's funnel plot showed that there was no publication bias (all P > 0.05). The present meta-analysis suggested that the maternal C677T polymorphism is a risk factor for CHDs in the Chinese Han population.

eNOS se correlaciona com a biogênese mitocondrial em corações com cardiopatia congênita e cianose / eNOS correlates with mitochondrial biogenesis in hearts of congenital heart disease with cyanosis

FUNDAMENTO: O programa de biogênese mitocondrial no coração parece apresentar remodelação adaptativa após estresse biomecânico e oxidativo. Os mecanismos adaptativos que protegem o metabolismo do miocárdio durante a hipóxia são coordenados, em parte, pelo óxido nítrico (NO). OBJETIVO: Observar a biogênese mitocondrial e expressão do óxido nítrico sintase (NOS) em corações de cardiopatia congênita com cianose; discutir a resposta mitocondrial à hipóxia crônica do miocárdio. MÉTODOS: Foram investigados 20 pacientes com defeitos cardíacos cianóticos (n = 10) ou acianóticos (n = 10). Foram estudadas amostras do miocárdio na via de saída ventricular direita, tomadas durante a operação. A análise morfométrica de mitocôndrias foi realizada por microscopia eletrônica de transmissão. A relação mtDNA/nDNA foi determinada com PCR em tempo real. Os níveis de transcrição da subunidade I da citocromo c oxidase (COXI), coativador-1α do receptor γ ativado por proliferador de peroxissoma (PGC-1α), o fator respiratório nuclear 1 (NRF1), e fator de transcrição mitocondrial A (Tfam) foram detectados por reação em cadeia da polimerase via transcriptase reversa (RT-PCR) ativado por fluorescência em tempo real. Os níveis proteicos de COXI e nNOS, iNOS e eNOS foram medidos por técnica de Western Blot. RESULTADOS: A densidade volumétrica mitocondrial (Vv) e a densidade numérica (Nv) foram significativamente elevadas em pacientes com cianose, em comparação com a cardiopatia congênita acianótica. MtDNA elevada e suprarregulação dos níveis de COXI, PGC-1 α, NRF1 e Tfam mRNA foram observadas em pacientes cianóticos. Os níveis de proteína de COXI e eNOS foram significativamente maiores no miocárdio de pacientes cianóticos que nos de acianóticos. Os níveis de transcrição do PGC-1α se correlacionam com os níveis de eNOS. CONCLUSÃO: A biogênese mitocondrial é ativada no miocárdio da via de saída ventricular na cardiopatia congênita com cianose, que ...

BACKGROUND: Mitochondrial biogenesis program in heart appears to exhibit adaptive remodeling following biomechanical and oxidative stress. The adaptive mechanisms that protect myocardium metabolism during hypoxia are coordinated in part by nitric oxide (NO). OBJECTIVE: To observe mitochondrial biogenesis and nitric oxide synthase (NOS) expression in hearts of congenital heart disease with cyanosis, discuss mitochondrial response to chronic hypoxia in myocardium. METHODS: 20 patients with cyanotic (n=10) or acyanotic cardiac defects (n=10) were investigated. Samples from the right ventricular outflow tract myocardium taken during operation were studied. Morphometric analysis of mitochondria was performed with transmission electron microscope. Relative mtDNA/nDNA ratio was determined with real-time PCR. Cytochrome c oxidase subunit I (COXI), peroxisome-proliferator-activated receptor γ coactivator-1α (PGC-1α), nuclear respiratory factor 1 (NRF1), and mitochondrial transcription factor A (Tfam) transcript levels were detected by real-time fluorescent RT-PCR. COXI and nNOS, iNOS and eNOS protein levels were measured with western blot. RESULTS: Mitochondrial volume density (Vv) and numerical density (Nv) were significantly elevated in patients with cyanotic compared to acyanotic congenital heart disease. Elevated mtDNA and up-regulated COXI, PGC-1α, NRF1 and Tfam mRNA levels were observed in cyanotic patients. Protein levels of COXI and eNOS were significantly higher in the myocardium of cyanotic than of acyanotic patients. PGC-1α transcript levels correlated with the levels of eNOS. Conclusion: Mitochondrial biogenesis is activated in right ventricular outflow tract myocardium in congenital heart disease with cyanosis, which could be the adaptive response to chronic hypoxia and possibly involves eNOS up-regulation. (Arq Bras Cardiol. 2012; [online].ahead print, PP.0-0).

eNOS correlates with mitochondrial biogenesis in hearts of congenital heart disease with cyanosis.

BACKGROUND: Mitochondrial biogenesis program in heart appears to exhibit adaptive remodeling following biomechanical and oxidative stress. The adaptive mechanisms that protect myocardium metabolism during hypoxia are coordinated in part by nitric oxide (NO). OBJECTIVE: To observe mitochondrial biogenesis and nitric oxide synthase (NOS) expression in hearts of congenital heart disease with cyanosis, discuss mitochondrial response to chronic hypoxia in myocardium. METHODS: 20 patients with cyanotic (n=10) or acyanotic cardiac defects (n=10) were investigated. Samples from the right ventricular outflow tract myocardium taken during operation were studied. Morphometric analysis of mitochondria was performed with transmission electron microscope. Relative mtDNA/nDNA ratio was determined with real-time PCR. Cytochrome c oxidase subunit I (COXI), peroxisome-proliferator-activated receptor γ coactivator-1α (PGC-1α), nuclear respiratory factor 1 (NRF1), and mitochondrial transcription factor A (Tfam) transcript levels were detected by real-time fluorescent RT-PCR. COXI and nNOS, iNOS and eNOS protein levels were measured with western blot. RESULTS: Mitochondrial volume density (Vv) and numerical density (Nv) were significantly elevated in patients with cyanotic compared to acyanotic congenital heart disease. Elevated mtDNA and up-regulated COXI, PGC-1α, NRF1 and Tfam mRNA levels were observed in cyanotic patients. Protein levels of COXI and eNOS were significantly higher in the myocardium of cyanotic than of acyanotic patients. PGC-1α transcript levels correlated with the levels of eNOS. CONCLUSION: Mitochondrial biogenesis is activated in right ventricular outflow tract myocardium in congenital heart disease with cyanosis, which could be the adaptive response to chronic hypoxia and possibly involves eNOS up-regulation.

A66G and C524T polymorphisms of the methionine synthase reductase gene are associated with congenital heart defects in the Chinese Han population.

Congenital heart defects (CHDs) are the most common birth defects; genes involved in homocysteine/folate metabolism may play important roles in CHDs. Methionine synthase reductase (MTRR) is one of the key regulatory enzymes involved in the metabolic pathway of homocysteine. We investigated whether two polymorphisms (A66G and C524T) of the MTRR gene are associated with CHDs. A total of 599 children with CHDs and 672 healthy children were included; the polymorphisms were detected by PCR and RFLP analysis. Significant differences in the distributions of A66G and C524T alleles were observed between CHD cases and controls, and slightly increased risks of CHD were associated with 66GG and 524CT genotypes (odds ratios = 1.545 and 1.419, respectively). The genotype frequencies of 524CT in the VSD subgroup, 66GG and 524CT in the PDA subgroup were significantly different from those of controls. In addition, the combined 66AA/524CT, 66AG/524CT and 66GG/524CT in CHDs had odds ratios = 1.589, 1.422 and 1.934, respectively. Increased risks were also observed in 66AA/524CT and 66GG/524CT for ASD, 66AG/524CT for VSD, as well as 66GG/524CT for PDA. In conclusion, MTRR A66G and C524T polymorphisms are associated with increased risk of CHDs.

Copper and ceruloplasmin in children undergoing heart surgery with cardiopulmonary bypass.

Heart surgery with cardiopulmonary bypass (CPB) nowadays has become a routine procedure. However, under nonadequate hemodynamic conditions and because of the changes related to ischemia-reperfusion, there is a possibility to provoke oxidative stress with all undesirable consequences. Copper (Cu) is closely related to this stress, taking part in the formation of the hazardous-free radicals. Meanwhile, at least in the pediatric area, little is known about Cu kinetics during cardiac surgery. The purpose of the present work was to study Cu and ceruloplasmin (Cp) dynamics during surgery with CPB in children. Twenty-one patients of both genders from Campo Grande, Brazil with congenital heart conditions were enrolled in the investigation. Blood samples were collected before the surgery and during and 24 h after it. Cu and Cp levels were measured at selected moments and the influence of hemodilution studied. It was concluded that serum Cu dynamics during cardiopulmonary bypass reflects the protective effects of this trace element. Ceruloplasmin levels correlate positively with copper.

Homocysteine concentrations and molecular analysis in patients with congenital heart defects.

BACKGROUND: Congenital heart defects are the result of incomplete heart development and, like many diseases, have been associated with high homocysteine concentration. METHODS: We evaluated homocysteine, folic acid and vitamin B(12) concentrations, and the mutations 677C>T and 1298A>C in MTHFR, 844ins68 in CBS and 2756A>G in MTR genes in 58 patients with congenital heart defects, 38 control subjects, and mothers of 49 patients and 26 controls. RESULTS: Control and patients presented normal range concentrations for homocysteine (7.66 +/- 3.16 microM and 6.95 +/- 3.12 microM, respectively), folic acid (8.31 +/- 3.00 ng/mL and 11.84 +/- 10.74 ng/mL) and vitamin B(12,) (613.56 +/- 307.57 pg/mL and 623.37 +/- 303.12 pg/mL), which did not differ among groups. For the mothers studied, homocysteine and vitamin B(12) concentrations also did not differ between groups. However, folic acid concentrations of mothers showed significant difference, the highest values being in the group of patients. No difference was found in allele frequencies among all groups studied. CONCLUSIONS: In the studied groups, high homocysteine seems not to be correlated with congenital heart defects, as well as folic acid and vitamin B(12). The mutations studied, in isolation, were not related to congenital heart defects, but high concentration of maternal homocysteine is associated with the presence of three or four mutated alleles.

Lack of evidence of association between MTHFR C677T polymorphism and congenital heart disease in a TDT study design.

INTRODUCTION: Hyperhomocysteinemia is frequently associated with congenital defects of the heart and neural tube. A common missense mutation in the MTHFR gene (C to T substitution at position 677 changing valine to alanine) produces a variant with reduced enzymatic action, resulting in higher plasma levels of homocysteine. The aim of this study is to investigate whether MTHFR C677T functional genetic variant is associated with an increased risk of congenital heart disease (CHD) development using a family-based case-control design and the Transmission Disequilibrium Test (TDT) approach. METHODS: We selected 91 consecutive patients with congenital heart disease for the study. From these patients we were able to obtain samples on 147 parents. The C677T polymorphism at the MTHFR gene was determined from each participant. RESULTS: A statistically significant association was disclosed in univariate analysis using a family-based case-control design (p<0.0001 assuming an additive genetic model, p<0.0001 assuming a dominant genetic model, and p=0.01 assuming a recessive genetic model). This association was explained by an increased frequency of the T allele in patients as compared to their fathers. However, by using a TDT approach a highly non-significant result was obtained and no association could be defined between this locus and congenital heart disease. CONCLUSIONS: We did not find sufficient evidence for an association between MTHFR C677T genotype and congenital heart disease in our study group. Previous reports on such association may be due to population genetic structure.

Influence of hypoxia on nitric oxide synthase activity and gene expression in children with congenital heart disease: a novel pathophysiological adaptive mechanism.

BACKGROUND: Chronic hypoxia has been shown to modulate nitric oxide (NO) responses in different cell models, but the relationship between hypoxia and NO synthase (NOS) regulation in humans was not studied. We studied the relationship between endothelial and inducible NOS (eNOS and iNOS) activities and expression and chronic hypoxia in children with cyanotic and acyanotic congenital heart defects. METHODS AND RESULTS: Right atrial tissue was excised from 18 patients during cardiac surgery. eNOS and iNOS activities were measured by conversion of L-[H(3)]arginine to L-[H(3)]citrulline. Gene expression of eNOS and iNOS was quantified by competitive reverse transcription-polymerase chain reaction. The eNOS activity and expression were significantly reduced in cyanotic hearts compared with acyanotic hearts: 0.38+/-0.14 versus 1.06+/-0.11 pmol. mg(-1). min(-1) (P<0.0001) and 0.54+/-0.08 versus 0.80+/-0.10 relative optical density (ROD) of cDNA (P<0.0001), respectively. In contrast, iNOS activity and expression were significantly higher in cyanotic than in acyanotic children: 7.04+/-1.20 versus 4.17+/-1.10 pmol. mg(-1). min(-1) (P<0.0001) and 2.55+/-0.11 versus 1.91+/-0.18 ROD of cDNA (P<0.0001), respectively. CONCLUSIONS: Hypoxia downregulates eNOS activity and gene expression in cardiac tissue from patients with cyanotic congenital heart defects. By contrast, iNOS activity and expression are increased in cyanotic children and may represent an alternative mechanism to counteract the effects of hypoxia in the cardiovascular system. Therefore, a novel adaptive mechanism during hypoxia is suggested.

Brain type creatine kinase in relation to oxygen desaturation in the blood of children with congenital heart disease.

The concentration of brain type creatine kinase (CK-BB) was measured in blood from the internal jugular vein in 32 children (less than 1 year old) with congenital heart disease. In transposition of the great arteries the CK-BB levels were significantly higher than in children without cyanosis (10.1 +/- 4.1 vs. 3.0 +/- 0.5 ng/ml). A negative correlation was found for CK-BB concentration and arterial oxygen saturation (r = -0.41, p less than 0.02 for all children and r = -0.62, p less than 0.05 for those with tetralogy of Fallot). It is suggested that the increased CK-BB levels in the blood of cyanotic children reflect chronic cerebral hypoxia, which may explain other reports of reduced psycho-intellectual function in patients with cyanotic heart disease.

[Creatine phosphokinase (CPK) and isoenzymes. Correlation with myocardial damage]. / Creatín-fosfoquinasa (CPK) e isoenzimas correlación con daño miocárdico.

1). The MB electrophoretic fraction of the serum CPK is specific in the diagnosis old acute myocardial infarction. 2). It allows us to differentiate ischaemia from myocardial necrosis. 3). The absence of this fraction, when found out during a period of 12 to 24 hours after the start of the angina attack allows us to deny the presence of acute myocardial infarction with a high index of precision. 4). Our results show that the serum sample should be obtained between 12 and 24 hours after starting the clinical case, in order to get a higher sensibility and specificity. 5). The quantification of MB fraction might be useful in the calculation of the amount of cardial muscle destroyed. When calculating the amount of cardial muscle destroyed of 125 cases (12.5%) with positive diagnosis of reinfarction and among the same 125, 12 were found occurring for the third time. Is possible that the real frequency of the iterative infarction is even higher, because many cases were dismissed (27.7%) for lack of electrocardiographic data, clearly pointing to myocardial transmural infarction. 6). Investigations were conduced about the evolutative condition of the danger factors.