The PPARGC1A Gly482Ser polymorphism is associated with left ventricular diastolic dysfunction in men

Association between self-reported alcohol consumption and diastolic dysfunction: a cross-sectional study

BACKGROUND AND OBJECTIVES

While alcohol consumption is associated with common risk factors for diastolic dysfunction the independent impact of low levels of alcohol consumption on this condition in a community setting is still unclear.Thus, the aim of this study was to explore this association in a representative population sample employing optimal echocardiographic techniques.

DESIGN

Cross-sectional observational study in community-based population.

SETTINGS, PARTICIPANTS AND METHODS

Participants between 30 and 75 years of age were consecutively invited to a physical examination, interview, conventional echocardiography, including Tissue Velocity Imaging. Diastolic dysfunction was defined according to the European Society of Cardiology criteria, excluding subjects with ejection fraction <45%, self-reported history of heart failure or atrial fibrillation on ECG. Self-reported alcohol intake using a validated questionnaire was categorised as no intake, low and medium-high intake.

RESULTS

In total, 500 men and 538 women (mean age 55.4±13) were successfully examined. Diastolic dysfunction was identified in 16% (79/500) of the men and 13% (58/538) of the women. The multivariable adjusted model revealed a strong and independent association between alcohol intake and diastolic dysfunction. In fact, using no alcohol intake as reference, diastolic dysfunction was independently associated with alcohol consumption in a dose-dependent fashion; low consumption, OR 2.3 (95% CI 1.3 to 4.0) and medium-high consumption OR 3.1 (95% CI 1.6 to 6.2), respectively.

CONCLUSION

There was a significant association between alcohol consumption and diastolic dysfunction starting already at low levels that was supported by a dose-dependent pattern. These results need confirmatory studies and are important in public health policies.

The peroxisome proliferator-activated receptor γ coactivator-1 alpha rs8192678 (Gly482Ser) variant and hepatitis B virus clearance

BACKGROUND

Chronic hepatitis B virus (CHB) infection is still incurable a major public health problem. It is yet unclear how host genetic factors influence the development of HBV infection. The peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A) has been shown to regulate hepatitis B virus (HBV). Several reports found that PPARGC1A variants are involved in a number of distinct liver diseases. Here we investigate whether the PPARGC1A rs8192678 (Gly482Ser) variant is involved in the spontaneous clearance of acute HBV infection and if it participates in chronic disease progression in Moroccan patients.

METHODS

Our study included 292 chronic hepatitis B (CHB) patients and 181 individuals who spontaneously cleared-HBV infection. We genotyped the rs8192678 SNP using a TaqMan allelic discrimination assay and then explored its association with spontaneous HBV clearance and CHB progression.

RESULTS

Our data showed that individuals carrying CT and TT genotypes were more likely to achieve spontaneous clearance (OR = 0.48, 95% CI (0.32-0.73), p = 0.00047; OR = 0.28, 95% CI (0.15-0.53), p = 0.00005, respectively). Subjects carrying the mutant allele T were more likely to achieve spontaneous clearance (OR = 0.51, 95% CI (0.38-0.67), P = 2.68E-06). However, when we investigated the impact of rs8192678 on the progression of liver diseases, we neither observe any influence (p > 0.05) nor found any significant association between ALT, AST, HBV viral loads, and the PPARGC1A rs8192678 genotypes in patients with CHB (p > 0.05).

CONCLUSION

Our result suggests that PPARGC1A rs8192678 may modulate acute HBV infection, and could therefore represent a potential predictive marker in the Moroccan population.

A diabetes-associated genetic variant is associated with diastolic dysfunction and cardiovascular disease

Aims

Although the epidemiological association between Type 2 diabetes and congestive heart failure (CHF) as well as cardiovascular disease (CVD) is well established, associations between diabetes‐related single‐nucleotide polymorphisms (SNPs), CHF, and CVD have been surprisingly inconclusive. Our aim is to examine if 43 diabetes‐related SNPs were associated with prevalent diastolic dysfunction assessed by echocardiography and incident CVD and/or CHF.

Methods and results

We genotyped 43 SNPs that previously reported genome‐wide significant associations with Type 2 diabetes, in 1444 subjects from the population‐based Malmö Preventive Project‐Re‐examination Study (MPP‐RES) (mean age 68 years; 29% women, 36% prevalent diabetes) (discovery cohort) and in 996 subjects from the VARA cohort (mean age 51 years, 52% women, 7% prevalent diabetes) (replication cohort). Multivariable logistic regression was assessed. Genetic variants that reached significant association with diastolic dysfunction in both cohorts were then analysed for association with incident CVD/CHF in a larger sample of the MPP‐RES cohort (3,407 cases and 11,776 controls, median follow up >30 years) using Cox regression analysis. A common variant at the HNF1B [major allele (T) coded, also the risk allele for diabetes] was the only SNP associated with increased risk of prevalent diastolic dysfunction in both the discovery [MPP‐RES; odds ratio (OR) 1.21, P = 0.024), and the replication cohort (VARA; OR 1.38, P = 0.042]. Cox regression analysis showed that carriers of the T‐allele of rs757210 had an increased risk of future CVD (HR 1.05, P = 0.042). No significant association was seen for incident CHF.

Conclusions

The diabetes susceptibility locus HNF1B is associated with prevalent diastolic dysfunction in two independent Swedish cohorts as well as incident cardiovascular disease.

Linking Metabolic Disease With the PGC-1α Gly482Ser Polymorphism

Peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) is a highly conserved transcriptional coactivator enriched in metabolically active tissues including liver, adipose, pancreas, and muscle. It plays a role in regulating whole body energy metabolism and its deregulation has been implicated in type 2 diabetes (T2D). A single nucleotide variant of the PPARGC1A gene (rs8192678) is associated with T2D susceptibility, relative risk of obesity and insulin resistance, and lower indices of β cell function. This common polymorphism is within a highly conserved region of the bioactive protein and leads to a single amino acid substitution (glycine 482 to serine). Its prevalence and effects on metabolic parameters appear to vary depending on factors including ethnicity and sex, suggesting important interactions between genetics and cultural/environmental factors and associated disease risk. Interestingly, carriers of the serine allele respond better to some T2D interventions, illustrating the importance of understanding functional impacts of genetic variance on PGC-1α when targeting this pathway for personalized medicine. This review summarizes a growing body of literature surrounding possible links between the PGC-1α Gly482Ser single nucleotide polymorphism and diabetes, with focus on key clinical findings, affected metabolic systems, potential molecular mechanisms, and the influence of geographical or ethnic background on associated risk.

Clinical characteristics of asymptomatic left ventricular diastolic dysfunction and its association with self-rated health and N-terminal B-type natriuretic peptide: a cross-sectional study

Aims

Left ventricular hypertrophy, obesity, hypertension, and N‐terminal B‐type natriuretic peptide (Nt‐proBNP) predict left ventricular diastolic dysfunction with preserved systolic function (DD‐PSF). Self‐rated health (SRH) is shown to be associated with chronic diseases, but the association of SRH with DD‐PSF is unclear. In light of the clinical implications of DD‐PSF, the following goals are of considerable importance: (1) to determine the role of SRH in patients with DD‐PSF in the general population and (2) to study the association between Nt‐proBNP and DD‐PSF.

Methods and results

The current study is a cross‐sectional study conducted on a random sampling of a rural population. Individuals 30–75 years of age were consecutively subjected to conventional echocardiography and tissue velocity imaging. Data were collected on 500 (48%) men and 538 (52%) women (n = 1038). DD‐PSF was the main outcome, and SRH and Nt‐proBNP were the primary indicators. Diabetes mellitus, hypertension, and obesity were accounted for as major confounders of the association with SRH. DD‐PSF was identified in 137 individuals, namely, 79 men (15.8%) and 58 women (10.8%). In a multivariate regression model, SRH (OR 2.95; 95% CI 1.02–8.57) and Nt‐proBNP (quartile 4 vs. quartile 1 OR 4.23; 95% CI 1.74–10.26) were both independently associated with DD‐PSF.

Conclusions

SRH, evaluated based on a descriptive question on general health, should be included in the diagnostic process of DD‐PSF. In agreement with previous studies, our study confirms that Nt‐proBNP is a major indicator of DD‐PSF.

The 482Ser of PPARGC1A and 12Pro of PPARG2 Alleles Are Associated with Reduction of Metabolic Risk Factors Even Obesity in a Mexican-Mestizo Population

The aim of this study was to investigate the relationship between functional polymorphisms Gly482Ser in PPARGC1A and Pro12Ala in PPARG2 with the presence of obesity and metabolic risk factors. We included 375 individuals characterized as Mexican-Mestizos and classified by the body mass index (BMI). Body dimensions and distribution of body fat were measured. The HOMA-IR and adiposity indexes were calculated. Adipokines and metabolic profile quantification were performed by ELISA and routine methods. Genetic polymorphisms were determined by polymerase chain reaction restriction fragment length polymorphism analysis. A difference between obese and nonobese subjects in polymorphism PPARGC1A distribution was observed. Among obese individuals, carriers of genotype 482Gly/Gly were observed to have decreased body fat, BMI, and body fat ratio versus 482Ser/Ser carriers and increased resistin and leptin levels in carriers Gly+ phenotype versus Gly- phenotype. Subjects with PPARG2 Ala- phenotype (genotype 12Pro/Pro) showed a decreased HOMA-IR index versus individuals with Ala+ phenotype (genotypes 12Pro/Ala plus 12Ala/Ala). We propose that, in obese Mexican-Mestizos, the combination of alleles 482Ser in PPARGC1A and 12Pro in PPARG2 represents a reduced metabolic risk profile, even when the adiposity indexes are increased.

Association between the PPARGC1A polymorphism and aerobic capacity in Japanese middle-aged men

OBJECTIVE

A lower frequency for the peroxisome proliferator-activated receptor γ coactivator 1α (PPARGC1A) Ser482 allele has been reported in elite-level endurance athletes among Caucasians, although this gene polymorphism has not been found to be associated with aerobic capacity in German, Dutch or Chinese populations. The purpose of the current study was to examine the associations between the Gly482Ser polymorphism and aerobic fitness in 112 Japanese middle-aged men.

METHODS

The PPARGC1A Gly482Ser polymorphism was identified according to a TaqMan(®) SNP genotyping assay. Habitual physical activity was objectively measured using an accelerometer. The lactate threshold (LT), an index of aerobic fitness, was measured based on a submaximal graded exercise test performed on an electric cycle ergometer. The association between the LT and the Gly482Ser polymorphism was assessed according to a multiple regression analysis and analysis of covariance, with adjustment for potential confounders (age, body mass index, cigarette smoking, physical activity level and regular exercise).

RESULTS

A significant association was observed between the PPARGC1A Gly482Ser polymorphism and LT, as carriers of the Ser482 had higher LT values than the Gly482 carriers.

CONCLUSION

The current results suggest that the PPARGC1A Ser482 allele is associated with a higher aerobic capacity in Japanese middle-aged men.

Impact of the PPARGC1A Gly482Ser polymorphism on left ventricular structural and functional abnormalities in patients with hypertension

The Gly482Ser polymorphism in the peroxisome proliferator-activated receptor gamma coactivator-1α (PPARGC1A) has been reported to contribute to the development of left ventricular (LV) hypertrophy. Little is known, however, about its possible impact on cardiac dysfunction. Enhanced myocardial fibrosis accompanying increased LV mass might represent a link with coexisting functional abnormalities. We investigated the association between the PPARGC1A Gly482Ser polymorphism and LV morphology and performance in essential hypertension, with special consideration of fibrosis intensity. A total of 205 hypertensive patients (60±8 years) underwent echocardiography with assessment of cardiac morphology, LV systolic (strain and strain rate) and diastolic function (peak early diastolic mitral flow velocity/peak late diastolic mitral flow velocity (E/A) ratio, peak early diastolic myocardial velocity (Em), and E/e' ratio (where e' is the peak early diastolic mitral annular velocity)), evaluation of serum procollagen type III amino-terminal propeptide (PIIINP) and procollagen type I carboxy-terminal propeptide (PICP)-markers of fibrosis and the PPARGC1A Gly482Ser genotyping. Subjects with the Ser-Ser genotype demonstrated more profound LV hypertrophy and diastolic function impairment, and higher PICP/PIIINP than the Ser-Gly and Gly-Gly groups. In multivariable analysis, the presence of the Ser-Ser allele was an independent correlate of E/e' (β=0.17, P<0.02), Em (β=-0.18, P<0.01) and LV mass index (β=0.28, P<0.001). In conclusion, in hypertensive patients, the PPARGC1A Gly482Ser polymorphism is associated with LV hypertrophy and diastolic dysfunction, with the presence of the Ser-Ser allele promoting these abnormalities. One of the possible mechanisms mediating the adverse effect on diastolic performance might be a relative increase in the anabolism of rigid collagen type I over that of the more elastic collagen type III, as indicated by an increased ratio of PICP to PIIINP.

Clusters of AMI risk factors and their association with left ventricular hypertrophy: a population-based study within the Skaraborg Project, Sweden

OBJECTIVES

Risk factors for acute myocardial infarction (AMI) are known to cluster and to be differently distributed in men and women. The aim of this study was to sex-specifically explore clusters of acknowledged AMI risk factors by factor analysis, and to study whether such clusters are associated with left ventricular hypertrophy (LVH), used as a subclinical measure of CHD.

METHODS

In 2001-2005, 2328 subjects (30-74 years) were randomly selected from two municipalities in Sweden (participation-rate 76%) and were assessed with regard to cardiovascular risk factors; 852 participants also had an echocardiographic examination performed.

RESULTS

Factor analysis identified three identical factors in men and women. WHR, HOMA-ir, systolic blood pressure, and ApoB/ApoA1 loaded significantly on the principal "metabolic factor", leisure-time physical activity and self-rated health loaded significantly on the "vitality factor", and smoking and alcohol consumption loaded significantly on the "addiction factor". The metabolic factor was associated with LVH in both men (P<0.001) and women (P<0.001), whereas the addiction factor was associated with LVH solely in men (P=0.002).

CONCLUSIONS

The consistent pattern in the clustering of acknowledged AMI risk factors suggests common underlying mechanisms in both men and women. However, whereas the metabolic factor was paramount in both men and women in the association with LVH, the addiction factor had an impact solely in men. As LVH often precedes AMI, a deeper understanding of risk factors for LVH, including consideration of the supposed sex differences, can be useful in order to explore prevention strategies for AMI.

The PPARGC1A gene Gly482Ser in Polish and Russian athletes

Peroxysome proliferator-activated receptor gamma coactivator-1-alpha (PGC-1α; encoded by the gene PPARGC1A in humans) is a crucial component in training-induced muscle adaptation because it is a co-activator of transcriptional factors that control gene expression in coordinated response to exercise. It has been suggested that a Gly482Ser substitution in PPARGC1A has functional relevance in the context of human disorders and athletic performance. To test this hypothesis, we examined the genotype distribution of PPARGC1A Gly482Ser in a group of Polish athletes and confirmed the results obtained in a replication study of Russian athletes. We found that the 482Ser allele was under-represented in the cohort of Polish and Russian athletes examined compared with unfit controls (P < 0.0001). A statistically significant low frequency of the 482Ser allele was observed among the endurance,strength-endurance, and sprint-strength groups of Polish athletes (P = 0.019, P = 0.022, and P < 0.0001, respectively). The replication study revealed that the 482Ser allele was also less prevalent in Russian endurance and strength-endurance athletes (P = 0.029 and P < 0.0001, respectively). Our results suggest that the PPARGC1A Gly482Ser polymorphism is associated with elite endurance athletic status. These findings support the hypothesis that the PPARGC1A 482Ser allele may impair aerobic capacity: thus, the Gly482 allele may be considered a beneficial factor for endurance performance.

Association of PGC-1alpha polymorphisms with age of onset and risk of Parkinson's disease

Background

Peroxisome proliferator-activated receptor-γ co-activator (PGC)-1α is a transcriptional co-activator of antioxidant genes and a master regulator of mitochondrial biogenesis. Parkinson's disease (PD) is associated with oxidative stress and mitochondrial dysfunction and recent work suggests a role for PGC-1α. We hypothesized that the rs8192678 PGC-1α single nucleotide polymorphism (SNP) may influence risk or age of onset of PD. The A10398G mitochondrial SNP has been inversely associated with risk of PD in some studies. In the current study we analyzed whether rs8192678 or other PGC-1α SNPs affect PD risk or age of onset, singularly or in association with the A10398G SNP.

Methods

Genomic DNA samples from 378 PD patients and 173 age-matched controls were analyzed by multiplexed probe sequencing, followed by statistical analyses of the association of each SNP, alone or in combination, with risk or age of onset of PD. Adjustments were made for age of onset being less than the age of sampling, and for the observed dependence between these two ages. The PD samples were obtained as two separate cohorts, therefore statistical methods accounted for different sampling methods between the two cohorts, and data were analyzed using Cox regression adjusted for sampling in the risk set definition and in the model.

Results

The rs8192678 PGC-1α SNP was not associated with the risk of PD. However, an association of the PGC-1α rs8192678 GG variant with longevity was seen in control subjects (p = 0.019). Exploratory studies indicated that the CC variant of rs6821591 was associated with risk of early onset PD (p = 0.029), with PD age of onset (p = 0.047), and with longevity (p = 0.022). The rs2970848 GG allele was associated with risk of late onset PD (p = 0.027).

Conclusions

These data reveal possible associations of the PGC-1α SNPs rs6821591 and rs2970848 with risk or age of onset of PD, and of the PGC-1α rs8192678 GG and the rs6821591 CC variants with longevity. If replicated in other datasets, these findings may have important implications regarding the role of PGC-1α in PD and longevity.

Diastolic dysfunction is associated with sedentary leisure time physical activity and smoking in females only

OBJECTIVES

Left ventricular diastolic dysfunction with preserved systolic function (DD-PSF) is associated with an increased risk of morbidity and mortality. Population-based surveys studying the associations between DD-PSF and lifestyle-associated risk factors, such as leisure time physical activity (LTPA) and smoking, are scarce. Thus, the aims were to explore the associations between DD-PSF and LTPA and smoking, employing optimal echocardiographic techniques.

DESIGN

Cross-sectional study conducted from 2001 to 2003.

SETTING

The study was conducted in a random sample of a rural Swedish population.

SUBJECTS

Men and women of 30-75 years of age were consecutively invited for conventional echocardiography and tissue velocity imaging (n = 1149). Structured questionnaires and physical examinations were conducted using standardized methods.

MAIN OUTCOME MEASURES

DD-PSF was defined according to the European Society of Cardiology criteria excluding subjects with ejection fraction < 45%, or a self-reported history of heart failure.

RESULTS

Complete information was available in 500 men and 538 women. In a multivariate model, DD-PSF was independently associated with sedentary LTPA and smoking in females; sedentary LTPA odds ratio (OR) 2.91, 95% confidence interval (CI) 1.02 to 8.27, and smoking OR 3.42, 95% CI 1.35 to 8.64. The probability of identifying DD-PSF in females with a sedentary LTPA was 37% and increased to 80% if they also had hypertension and were obese.

CONCLUSIONS

Sedentary LTPA and smoking are independently associated with DD-PSF in females. Identification of a sedentary lifestyle in females increases the probability of diagnosing DD-PSF.

Application of serial analysis of gene expression to the study of human genetic disease

Sequence tag analysis using serial analysis of gene expression (SAGE) is a powerful strategy for the quantitative analysis of gene expression in human genetic disorders. SAGE facilitates the measurement of mRNA transcripts and generates a non-biased gene expression profile of normal and pathological disease tissue. In addition, the SAGE technique has the capacity of detecting the expression of novel transcripts allowing for the identification of previously uncharacterised genes, thus providing a unique advantage over the traditional microarray-based approach for expression profiling. The technique has been successful in providing pathological gene expression profiles in a number of common genetic disorders including diabetes, cardiovascular disease, Parkinson disease and Down syndrome. When combined with next generation sequencing platforms, SAGE has the potential to become a more powerful and sensitive technique making it more amenable for diagnostic use. This review will therefore discuss the application of SAGE to several common genetic disorders and will further evaluate its potential use in diagnosing human genetic disease.