Project description:To assess in a US general adult population the effect of the functional single-nucleotide polymorphism rs198389 in the promoter region of the gene of brain-type natriuretic peptide (BNP) on 3 commonly used BNP assays, clinical phenotype, disease prevalence, overall survival, and diagnostic test characteristics of BNP as a biomarker.We genotyped for rs198389 in a random sample of the general population (aged ? 45 years; n = 1970; enrolled between June 1, 1997, and September 30, 2000) from Olmsted County, Minnesota. Patients were characterized biochemically, clinically, echocardiographically, and regarding BNP molecular forms (2 assays for BNP and 1 assay for amino-terminal proBNP). Median follow-up was 9 years.Genotype frequencies were in Hardy-Weinberg equilibrium (P = .98): TT genotype, n = 645 (32.7%); TC genotype, n = 983 (49.9%); and CC genotype, n = 342 (17.4%). The C allele independently predicted higher BNP forms (P<.001 for all assays). Genotypes did not differ with regard to clinical and echocardiographic phenotype or overall survival. When previously reported genotype-unadjusted cut points for the detection of left ventricular ejection fraction less than or equal to 40% (n = 37 [1.9%]) and less than or equal to 50% (n = 116 [6.0%]) were used, sensitivity generally increased with the number of C alleles, whereas specificity decreased, both on average by more than 10% for the TT vs CC genotype.The C allele of rs198389 is common in the general US population and is associated with higher concentrations of BNP molecular forms but not with cardiovascular phenotype or survival. The C allele confounds the test characteristics of commonly used assays.
Project description:BACKGROUND:Atrial natriuretic peptide (ANP) has antihypertrophic and antifibrotic properties that are relevant to AF substrates. The -G664C and rs5065 ANP single nucleotide polymorphisms (SNP) have been described in association with clinical phenotypes, including hypertension and left ventricular hypertrophy. A recent study assessed the association of early AF and rs5065 SNPs in low-risk subjects. In a Caucasian population with moderate-to-high cardiovascular risk profile and structural AF, we conducted a case-control study to assess whether the ANP -G664C and rs5065 SNP associate with nonfamilial structural AF. METHODS:168 patients with nonfamilial structural AF and 168 age- and sex-matched controls were recruited. The rs5065 and -G664C ANP SNPs were genotyped. RESULTS:The study population had a moderate-to-high cardiovascular risk profile with 86% having hypertension, 23% diabetes, 26% previous myocardial infarction, and 23% left ventricular systolic dysfunction. Patients with AF had greater left atrial diameter (44 ± 7 vs. 39 ± 5 mm; P < 0.001) and higher plasma NTproANP levels (6240 ± 5317 vs. 3649 ± 2946 pmol/mL; P < 0.01). Odds ratios (ORs) for rs5065 and -G664C gene variants were 1.1 (95% confidence interval [CI], 0.7-1.8; P = 0.71) and 1.2 (95% CI, 0.3-3.2; P = 0.79), respectively, indicating no association with AF. There were no differences in baseline clinical characteristics among carriers and noncarriers of the -664C and rs5065 minor allele variants. CONCLUSIONS:We report lack of association between the rs5065 and -G664C ANP gene SNPs and AF in a Caucasian population of patients with structural AF. Further studies will clarify whether these or other ANP gene variants affect the risk of different subphenotypes of AF driven by distinct pathophysiological mechanisms.
Project description:ObjectivesThe purpose of this study was to investigate circulating pro-B-type natriuretic peptide (proBNP(1-108)) in the general community and evaluate its ability to detect left ventricular (LV) dysfunction.BackgroundThe current concept for cardiac endocrine function is that, in response to cardiac stress, the heart secretes B-type natriuretic peptide (BNP(1-32)) and amino-terminal pro-B-type natriuretic peptide (NT-proBNP(1-76)) after intracardiac cleavage of their molecular precursor, proBNP(1-108). We hypothesized that proBNP(1-108) circulates in normal human subjects and that it is a useful biomarker for LV dysfunction.MethodsOur population-based study included a cohort of 1,939 adults (age ≥45 years) from Olmsted County, Minnesota, with 672 participants defined as healthy. Subjects underwent in-depth clinical characterization, detailed echocardiography, and measurement of proBNP(1-108). Independent factors associated with proBNP(1-108) and test characteristics for the detection of LV dysfunction were determined.ResultsProBNP(1-108) in normal humans was strongly influenced by sex, age, heart rate, and body mass index. The median concentration was 20 ng/l with a mean proBNP(1-108) to NT-proBNP(1-76) ratio of 0.366, which decreased with heart failure stage. ProBNP(1-108) was a sensitive (78.8%) and specific (86.1%) biomarker for detecting LV systolic dysfunction, which was comparable to BNP(1-32), but less than NT-proBNP(1-76), in several subsets of the population.ConclusionsProBNP(1-108) circulates in the majority of healthy humans in the general population and is a sensitive and specific biomarker for the detection of systolic dysfunction. The proBNP(1-108) to NT-proBNP(1-76) ratio may provide insights into altered proBNP(1-108) processing during heart failure progression. Thus, this highly specific assay for proBNP(1-108) provides important new insights into the biology of the BNP system.
Project description:Cardiomyocytes secrete atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) in response to mechanical stretching, making them useful clinical biomarkers of cardiac stress. Both human and animal studies indicate a role for ANP as a regulator of blood pressure with conflicting results for BNP. We used genome-wide association analysis (n=6296) to study the effects of genetic variants on circulating natriuretic peptide concentrations and compared the impact of natriuretic peptide-associated genetic variants on blood pressure (n=27 059). Eight independent genetic variants in 2 known (NPPA-NPPB and POC1B-GALNT4) and 1 novel locus (PPP3CC) associated with midregional proANP (MR-proANP), BNP, aminoterminal proBNP (NT-proBNP), or BNP:NT-proBNP ratio. The NPPA-NPPB locus containing the adjacent genes encoding ANP and BNP harbored 4 independent cis variants with effects specific to either midregional proANP or BNP and a rare missense single nucleotide polymorphism in NT-proBNP seriously altering its measurement. Variants near the calcineurin catalytic subunit gamma gene PPP3CC and the polypeptide N-acetylgalactosaminyltransferase 4 gene GALNT4 associated with BNP:NT-proBNP ratio but not with BNP or midregional proANP, suggesting effects on the post-translational regulation of proBNP. Out of the 8 individual variants, only those correlated with midregional proANP had a statistically significant albeit weak impact on blood pressure. The combined effect of these 3 single nucleotide polymorphisms also associated with hypertension risk (P=8.2×10-4). Common genetic differences affecting the circulating concentration of ANP associated with blood pressure, whereas those affecting BNP did not, highlighting the blood pressure-lowering effect of ANP in the general population.
Project description:C-type natriuretic peptide (CNP) is an endothelium-derived peptide that is released as a protective mechanism in response cardiovascular injury or disease. However, no studies have investigated circulating CNP, identifying clinical factors that may influence CNP and its relationship to cardiovascular disease in the general population. We studied 1841 randomly selected subjects from Olmsted County, MN (mean age, 63±11 years; 48% men). Plasma CNP was measured by a well-established radioimmunoassay and echocardiography, clinical characterization, and detailed medical record review were performed. We report that CNP circulates at various concentrations (median, 13 pg/mL), was unaffected by sex, was weakly associated by age, and that highest quartile of CNP identified a high-risk phenotype. Subjects with CNP in the highest quartile were associated with increased risk of myocardial infarction (multivariable-adjusted hazard ratio, 1.51; 95% confidence interval, 1.09-2.09; P=0.01) but not heart failure, cerebrovascular accidents, or death during a follow-up of 12 years. Addition of the highest quartile of CNP to clinical variables led to a modest increase in the integrated discrimination improvement for risk of myocardial infarction. In a large community-based cohort, elevated circulating CNP identified a high-risk phenotype that included cardiovascular comorbidities and left ventricular dysfunction, and provided evidence that highest concentrations of CNP potentially has prognostic value in predicting future risk of myocardial infarction. Together, these data from the general population highlight the potential value of CNP and support the need for additional studies to evaluate whether mechanisms regulating CNP could improve outcomes.
Project description:The expression of natriuretic peptides in the neural bundles of the anterior portion of the optic nerves and their functions in regulating vessel tone and blood flow may suggest a possible role in the pathogenesis of glaucoma. The purpose of this study was to investigate the association between normal-tension glaucoma and the genetic variations of atrial natriuretic peptide (Nppa) and natriuretic peptide receptor A (Npr1) gene.Sixty-seven Korean normal-tension glaucoma (NTG) patients and 100 healthy subjects (as normal controls) were enrolled. DNA from peripheral blood leukocytes was extracted, and the genotypes of five polymorphisms (c.94G>A, c.454T>C, IVS1+16C>T, IVS2+701G>A, and c.-764C>G) in the Nppa gene and one polymorphism (c.1023G>C) in the Npr1 gene were determined using the restriction fragment length polymorphism and the SNaPshot methods. The genotype and allele frequencies of these polymorphisms in patients with NTG and normal controls were compared using the Fisher's exact test and the chi-square test.In both groups, the genotype distributions were in accordance with the Hardy-Weinberg equilibrium. There was no significant difference in the frequency of the Nppa and Npr1 alleles or genotypes in the normal-tension glaucoma group as compared to the control group.Nppa and Npr1 gene polymorphisms are not associated with normal-tension glaucoma, suggesting that this gene does not have an important role in the pathogenesis of optic neuropathy in this disease.
Project description:BACKGROUND: RECQL is a DNA helicase involved in DNA mismatch repair. The RECQL polymorphism, 3' untranslated region (UTR) A159C, was previously associated with overall survival of patients with resectable pancreatic adenocarcinoma treated with neoadjuvant chemoradiation. In the present study, we examined RECQL for somatic mutations and other polymorphisms and compared these findings with the outcome in patients who received adjuvant or neoadjuvant chemoradiation. We hypothesized that RECQL (i) would be mutated in cancer, (ii) would have polymorphisms linked to the 3'UTR A159C and that either or both events would affect function. We also hypothesized that (iii) these changes would be associated with survival in both cohorts of patients. MATERIAL AND METHODS: We sequenced RECQL's 15 exons and surrounding sequences in paired blood and tumour DNA of 39 patients. The 3'UTR A159C genotype was determined in blood DNA samples from 176 patients with resectable pancreatic adenocarcinoma treated with adjuvant (53) or neoadjuvant (123) chemoradiation. Survival was calculated using the Kaplan-Meier method, with log rank comparisons between groups. The relative impact of genotype on time to overall survival was performed using the Cox proportional hazards model. RESULTS: Somatic mutations were found in UTRs and intronic regions but not in exonic coding regions of the RECQL gene. Two single nucleotide polymorphisms (SNPs), located in introns 2 and 11, were found to be part of the same haplotype block as the RECQL A159C SNP and showed a similar association with overall survival. No short-term difference in survival between treatment strategies was found. We identified a subgroup of patients responsive to neoadjuvant therapy in which the 159 A allele conferred strikingly improved long-term survival. DISCUSSION: The RECQL 3'UTR A159C SNP is not linked with other functional SNPs within RECQL but may function as a site for regulatory molecules. The mechanism of action needs to be clarified further.
Project description:The study of gene regulatory network and protein-protein interaction network is believed to be fundamental to the understanding of molecular processes and functions in systems biology. In this study, the authors are interested in single nucleotide polymorphism (SNP) level and construct SNP-SNP interaction network to understand genetic characters and pathogenetic mechanisms of complex diseases. The authors employ existing methods to mine, model and evaluate a SNP sub-network from SNP-SNP interactions. In the study, the authors employ the two SNP datasets: Parkinson disease and coronary artery disease to demonstrate the procedure of construction and analysis of SNP-SNP interaction networks. Experimental results are reported to demonstrate the procedure of construction and analysis of such SNP-SNP interaction networks can recover some existing biological results and related disease genes.
Project description:We sought to define the cardiometabolic phenotype associated with rs5068, a genetic variant of the atrial natriuretic peptide (ANP) gene.The ANP and B-type natriuretic peptide play an important role in cardiorenal homeostasis but also exert metabolic actions.We genotyped 1,608 randomly selected residents from Olmsted County, Minnesota. Subjects were well-characterized.Genotype frequencies were: AA 89.9%, AG 9.7%, and GG 0.4%; all subsequent analyses were AA versus AG+GG. The G allele was associated with increased plasma levels of N-terminal pro-atrial natriuretic peptide (p = 0.002), after adjustment for age and sex. The minor allele was also associated with lower body mass index (BMI) (p = 0.006), prevalence of obesity (p = 0.002), waist circumference (p = 0.021), lower levels of C-reactive protein (p = 0.027), and higher values of high-density lipoprotein cholesterol (p = 0.019). The AG+GG group had a lower systolic blood pressure (p = 0.011) and lower prevalence of myocardial infarction (p = 0.042). The minor allele was associated with a lower prevalence of metabolic syndrome (p = 0.025). The associations between the G allele and high-density lipoprotein cholesterol, C-reactive protein values, myocardial infarction, and metabolic syndrome were not significant, after adjusting for BMI; the associations with systolic blood pressure, BMI, obesity, and waist circumference remained significant even after adjusting for N-terminal pro-atrial natriuretic peptide.In a random sample of the general U.S. population, the minor allele of rs5068 is associated with a favorable cardiometabolic profile. These findings suggest that rs5068 or genetic loci in linkage disequilibrium might affect susceptibility for cardiometabolic diseases and support the possible protective role of natriuretic peptides by their favorable effects on metabolic function. Replication studies are needed to confirm our findings.