Increased risk of obesity associated with the variant allele of the PPARGC1A Gly482Ser polymorphism in physically inactive elderly men

The rs17782313 polymorphism near MC4R gene confers a high risk of obesity and hyperglycemia, while PGC1α rs8192678 polymorphism is weakly correlated with glucometabolic disorder: a systematic review and meta-analysis

Background

The relationships of the rs17782313 polymorphism near melanocortin 4 receptor gene (MC4R) and the rs8192678 polymorphism in peroxisome proliferator-activated receptor gamma coactivator 1 alpha gene (PGC1α) with metabolic abnormalities have been explored in many populations around the world, but the findings were not all consistent and sometimes even a bit contradictory.

Methods

Electronic databases including Medline, Scopus, Embase, Web of Science, CNKI and Google Scholar were checked for studies that met the inclusion criteria. Data were carefully extracted from eligible studies. Standardized mean differences (SMDs) were calculated by using a random-effects model to examine the differences in the indexes of obesity, glucometabolic disorder and dyslipidemia between the genotypes of the rs17782313 and rs8192678 polymorphisms. Cochran's Q-statistic test and Begg's test were employed to identify heterogeneity among studies and publication bias, respectively.

Results

Fifty studies (58,716 subjects) and 51 studies (18,660 subjects) were respectively included in the pooled meta-analyses for the rs17782313 and rs8192678 polymorphisms. The C-allele carriers of the rs17782313 polymorphism had a higher average level of body mass index (SMD = 0.21 kg/m2, 95% confidence interval [95% CI] = 0.12 to 0.29 kg/m2, p < 0.001), waist circumference (SMD = 0.14 cm, 95% CI = 0.06 to 0.23 cm, p < 0.001) and blood glucose (SMD = 0.09 mg/dL, 95% CI = 0.02 to 0.16 mg/dL, p = 0.01) than the TT homozygotes. Regarding the rs8192678 polymorphism, no significant associations with the indexes of obesity, glucometabolic disorder and dyslipidemia were detected. However, significant correlations between the rs8192678 polymorphism and multiple glucometabolic indexes were observed in subgroup analyses stratified by sex, age, ethnicity and health status.

Conclusion

The meta-analysis demonstrates that the C allele of the MC4R rs17782313 polymorphism confers a higher risk of obesity and hyperglycemia, and the PGC1α rs8192678 polymorphism is weakly correlated with glucometabolic disorder. These findings may partly explain the relationships between these variants and diabetes as well as cardiovascular disease.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022373543.

Gene Polymorphism and Total Genetic Score in Martial Arts Athletes with Different Athletic Qualifications

The personalized approach in sports genetics implies considering the allelic variants of genes in polymorphic loci when adjusting the training process of athletes. The personalized approach is used both in sports genetics and in medicine to identify the influence of genotype on the manifestations of human physical qualities that allow to achieve high sports results or to assess the impact of genotype on the development and course of diseases. The impact of genes of the renin-angiotensin and kinin-bradykinin systems in the development of cardiovascular disease in athletes has not been defined. This study aims to determine the polymorphisms of four genes (ACE, BDKRB2, PPARGC1A and NOS3) and the total genetic score to reveal the predisposition to the formation of physical qualities in martial arts athletes with different athletic abilities. The products of these four genes are involved in the control of blood pressure. The allelic variants of these genes are associated with the development of the physical quality "endurance" and have an indirect influence on the formation of speed and power qualities. The total genetic score (TGS: from 0 to 100 arbitrary units) was calculated from the genotype score in each polymorphism. The athletes were divided into Group I with high and Group II with low qualifications depending on their sports success. Single nucleotide polymorphisms (SNPs) are identified through restriction endonucleases cleavage for PCR amplicons for discriminating between alleles of the target genes ACE (rs4646994), BDKRB2 (rs5810761), PPARGC1A (rs8192673) and NOS3 (rs1799983). Significant differences between the allelic variants of target genes and athletic ability were found between Group I and Group II for genotype G/G of NOS3 gene and genotypes Gly/Gly and Gly/Ser of PPARGC1A gene. The data obtained confirm that athletes with unfavourable genotypes are excluded in the screening phase because their endurance is not fully developed to the required level in martial arts. Martial arts athletes with the highest TGS have the highest skill level. Polymorphic loci of four genes whose products are involved in blood pressure control (ACE, BDKRB2, NOS3 and PPARGC1A) can be used in martial arts not only to determine predisposition to cardiovascular disease but also to predispose to the development of speed and power qualities and endurance. The total genetic score can serve as a tool for predicting athletic success.

Associations of Polymorphisms in the Peroxisome Proliferator-Activated Receptor Gamma Coactivator-1 Alpha Gene With Subsequent Coronary Heart Disease: An Individual-Level Meta-Analysis

Background: The knowledge of factors influencing disease progression in patients with established coronary heart disease (CHD) is still relatively limited. One potential pathway is related to peroxisome proliferator–activated receptor gamma coactivator-1 alpha (PPARGC1A), a transcription factor linked to energy metabolism which may play a role in the heart function. Thus, its associations with subsequent CHD events remain unclear. We aimed to investigate the effect of three different SNPs in the PPARGC1A gene on the risk of subsequent CHD in a population with established CHD.

Methods: We employed an individual-level meta-analysis using 23 studies from the GENetIcs of sUbSequent Coronary Heart Disease (GENIUS-CHD) consortium, which included participants (n = 80,900) with either acute coronary syndrome, stable CHD, or a mixture of both at baseline. Three variants in the PPARGC1A gene (rs8192678, G482S; rs7672915, intron 2; and rs3755863, T528T) were tested for their associations with subsequent events during the follow-up using a Cox proportional hazards model adjusted for age and sex. The primary outcome was subsequent CHD death or myocardial infarction (CHD death/myocardial infarction). Stratified analyses of the participant or study characteristics as well as additional analyses for secondary outcomes of specific cardiovascular disease diagnoses and all-cause death were also performed.

Results: Meta-analysis revealed no significant association between any of the three variants in the PPARGC1A gene and the primary outcome of CHD death/myocardial infarction among those with established CHD at baseline: rs8192678, hazard ratio (HR): 1.01, 95% confidence interval (CI) 0.98–1.05 and rs7672915, HR: 0.97, 95% CI 0.94–1.00; rs3755863, HR: 1.02, 95% CI 0.99–1.06. Similarly, no significant associations were observed for any of the secondary outcomes. The results from stratified analyses showed null results, except for significant inverse associations between rs7672915 (intron 2) and the primary outcome among 1) individuals aged ≥65, 2) individuals with renal impairment, and 3) antiplatelet users.

Conclusion: We found no clear associations between polymorphisms in the PPARGC1A gene and subsequent CHD events in patients with established CHD at baseline.

Gene Network Analysis for Osteoporosis, Sarcopenia, Diabetes, and Obesity in Human Mesenchymal Stromal Cells

The systemic gene interactions that occur during osteoporosis and their underlying mechanisms remain to be determined. To this end, mesenchymal stromal cells (MSCs) were analyzed from bone marrow samples collected from healthy individuals (n = 5) and patients with osteoporosis (n = 5). A total of 120 osteoporosis-related genes were identified using RNA-sequencing (RNA-seq) and Ingenuity Pathway Analysis (IPA) software. In order to analyze these genes, we constructed a heatmap of one-way hierarchical clustering and grouped the gene expression patterns of the samples. The MSCs from one control participant showed a similar expression pattern to that observed in the MSCs of three patients with osteoporosis, suggesting that the differentiating genes might be important genetic determinants of osteoporosis. Then, we selected the top 38 genes based on fold change and expression, excluding osteoporosis-related genes from the control participant. We identified a network among the top 38 genes related to osteoblast and osteoclast differentiation, bone remodeling, osteoporosis, and sarcopenia using the Molecule Activity Predictor program. Among them, 25 genes were essential systemic genes involved in osteoporosis. Furthermore, we identified 24 genes also associated with diabetes and obesity, among which 10 genes were involved in a network related to bone and energy metabolism. The study findings may have implications for the treatment and prevention of osteoporosis.

Computational Analysis of Gly482Ser Single-Nucleotide Polymorphism in PPARGC1A Gene Associated with CAD, NAFLD, T2DM, Obesity, Hypertension, and Metabolic Diseases

Peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PPARGC1A) regulates the expression of energy metabolism's genes and mitochondrial biogenesis. The essential roles of PPARGC1A encouraged the researchers to assess the relation between metabolism-related diseases and its variants. To study Gly482Ser (+1564G/A) single-nucleotide polymorphism (SNP) after PPARGC1A modeling, we substitute Gly482 for Ser482. Stability prediction tools showed that this substitution decreases the stability of PPARGC1A or has a destabilizing effect on this protein. We then utilized molecular dynamics simulation of both the Gly482Ser variant and wild type of the PPARGC1A protein to analyze the structural changes and to reveal the conformational flexibility of the PPARGC1A protein. We observed loss flexibility in the RMSD plot of the Gly482Ser variant, which was further supported by a decrease in the SASA value in the Gly482Ser variant structure of PPARGC1A and an increase of H-bond with the increase of β-sheet and coil and decrease of turn in the DSSP plot of the Gly482Ser variant. Such alterations may significantly impact the structural conformation of the PPARGC1A protein, and it might also affect its function. It showed that the Gly482Ser variant affects the PPARGC1A structure and makes the backbone less flexible to move. In general, molecular dynamics simulation (MDS) showed more flexibility in the native PPARGC1A structure. Essential dynamics (ED) also revealed that the range of eigenvectors in the conformational space has lower extension of motion in the Gly482Ser variant compared with WT. The Gly482Ser variant also disrupts PPARGC1A interaction. Due to this single-nucleotide polymorphism in PPARGC1A, it became more rigid and might disarray the structural conformation and catalytic function of the protein and might also induce type 2 diabetes mellitus (T2DM), coronary artery disease (CAD), and nonalcoholic fatty liver disease (NAFLD). The results obtained from this study will assist wet lab research in expanding potent treatment on T2DM.

Container-aided integrative QTL and RNA-seq analysis of Collaborative Cross mice supports distinct sex-oriented molecular modes of response in obesity

BACKGROUND

The Collaborative Cross (CC) mouse population is a valuable resource to study the genetic basis of complex traits, such as obesity. Although the development of obesity is influenced by environmental factors, underlying genetic mechanisms play a crucial role in the response to these factors. The interplay between the genetic background and the gene expression pattern can provide further insight into this response, but we lack robust and easily reproducible workflows to integrate genomic and transcriptomic information in the CC mouse population.

RESULTS

We established an automated and reproducible integrative workflow to analyse complex traits in the CC mouse genetic reference panel at the genomic and transcriptomic levels. We implemented the analytical workflow to assess the underlying genetic mechanisms of host susceptibility to diet induced obesity and integrated these results with diet induced changes in the hepatic gene expression of susceptible and resistant mice. Hepatic gene expression differs significantly between obese and non-obese mice, with a significant sex effect, where male and female mice exhibit different responses and coping mechanisms.

CONCLUSION

Integration of the data showed that different genes but similar pathways are involved in the genetic susceptibility and disturbed in diet induced obesity. Genetic mechanisms underlying susceptibility to high-fat diet induced obesity are different in female and male mice. The clear distinction we observed in the systemic response to the high-fat diet challenge and to obesity between male and female mice points to the need for further research into distinct sex-related mechanisms in metabolic disease.

Factors Predicting the Utilization of Center-Based Cardiac Rehabilitation Program

Although cardiac rehabilitation (CR) is clearly beneficial to improving patients’ physical functioning and reducing heart disease progression, significant proportions of patients do not complete CR programs. To evaluate the prevalence and predictors of completion of a center-based CR program in eligible cardiac patients, existing data collected from electronic medical records were used. To identify the predictors of CR completion, we used principal components analysis (PCA) and an artificial neural network (ANN) module. Among 685 patients, 61.4% (n = 421) completed the program, 31.7% (n = 217) dropped out, and 6.9% (n = 47) were referred but failed to initiate the program. PCA was conducted to consolidate baseline data into three factors—(1) psychosocial factors (depression, anxiety, and quality of life), (2) age, and (3) BMI, which explained 66.8% of the total variance. The ANN model produced similar results as the PCA. Patients who completed CR sessions had greater extremity strength and flexibility, longer six-minute walk distance, more CR knowledge, and a better quality of life. The present study demonstrated that patients who were older, obese, and who had depression, anxiety, or a low quality of life were less likely to complete the CR program.

Association of Candidate Gene Polymorphism with Metabolic Syndrome among Mongolian Subjects: A Case-Control Study

Metabolic syndrome (MetS) is complex and determined by the interaction between genetic and environmental factors and their influence on obesity, insulin resistance, and related traits associated with diabetes and cardiovascular disease risk. Some dynamic markers, including adiponectin (ADIPOQ), brain-derived neurotrophic factor (BDNF), and lipoprotein lipase (LPL), are implicated in MetS; however, the influence of their genetic variants on MetS susceptibility varies in racial and ethnic groups. We investigated the association of single nucleotide polymorphism (SNP)-SNP interactions among nine SNPs in six genes with MetS's genetic predisposition in Mongolian subjects. A total of 160 patients with MetS for the case group and 144 healthy individuals for the control group were selected to participate in this study. Regression analysis of individual SNPs showed that the ADIPOQ + 45GG (odds ratio (OR) = 2.09, p = 0.011) and P⁺P⁺ of LPL PvuII (OR = 2.10, p = 0.038) carriers had an increased risk of MetS. Conversely, G allele of LPL S447X (OR = 0.45, p = 0.036) and PGC-1α 482Ser (OR = 0.26, p = 0.001) allele were estimated as protective factors, respectively. Moreover, a haplotype containing the G-P⁺-G combination was related to MetS. Significant loci were also related to body mass index (BMI), systolic blood pressure (SBP), serum high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), and fasting blood glucose (FBG), adipokines, and insulin as well as insulin resistance (p < 0.05). Our results confirm that ADIPOQ + 45T > G, LPL PvII, and PGC-1α Gly482Ser loci are associated with MetS in Mongolian subjects.

Identification of Molecular Mechanisms Related to Pig Fatness at the Transcriptome and miRNAome Levels

Fat deposition and growth rate are closely related to pork quality and fattening efficiency. The next-generation sequencing (NGS) approach for transcriptome and miRNAome massive parallel sequencing of adipocyte tissue was applied to search for a molecular network related to fat deposition in pigs. Pigs were represented by three breeds (Large White, Pietrain, and Hampshire) that varied in fat content within each breed. The obtained results allowed for the detection of significant enrichment of Gene Ontology (GO) terms and pathways associated directly and indirectly with fat deposition via regulation of fatty acid metabolism, fat cell differentiation, inflammatory response, and extracellular matrix (ECM) organization and disassembly. Moreover, the results showed that adipocyte tissue content strongly affected the expression of leptin and other genes related to a response to excessive feed intake. The findings indicated that modification of genes and miRNAs involved in ECM rearrangements can be essential during fat tissue growth and development in pigs. The identified molecular network within genes and miRNAs that were deregulated depending on the subcutaneous fat level are proposed as candidate factors determining adipogenesis, fatness, and selected fattening characteristics in pigs.

Metabolic, Molecular, and Behavioral Effects of Western Diet in Serotonin Transporter-Deficient Mice: Rescue by Heterozygosity?

Reduced function of the serotonin transporter (SERT) is associated with increased susceptibility to anxiety and depression and with type-2 diabetes, which is especially true in older women. Preference for a "Western diet" (WD), enriched with saturated fat, cholesterol, and sugars, may aggravate these conditions. In previous studies, decreased glucose tolerance, central and peripheral inflammation, dyslipidemia, emotional, cognitive, and social abnormalities were reported in WD-fed young female mice. We investigated the metabolic, molecular, and behavioral changes associated with a 3-week-long dietary regime of either the WD or control diet in 12-month-old female mice with three different Sert genotypes: homozygous (Slc6a4) gene knockout (Sert ^-/-: KO), heterozygous (Sert ^+/-: HET), or wild-type mice (Sert ^+/+: WT). In the WT-WD and KO-WD groups, but not in HET-WD-fed mice, most of changes induced by the WD paralleled those found in the younger mice, including brain overexpression of inflammatory marker Toll-like receptor 4 (Tlr4) and impaired hippocampus-dependent performance in the marble test. However, the 12-month-old female mice became obese. Control diet KO mice exhibited impaired hippocampal-dependent behaviors, increased brain expression of the serotonin receptors Htr2c and Htr1b, as well as increased Tlr4 and mitochondrial regulator, peroxisome proliferator-activated receptor gamma-coactivator-1a (Ppargc1a). Paradoxically, these, and other changes, were reversed in KO-WD mutants, suggesting a complex interplay between Sert deficiency and metabolic factors as well as potential compensatory molecular mechanisms that might be disrupted by the WD exposure. Most, but not all, of the changes in gene expression in the brain and liver of KO mice were not exhibited by the HET mice fed with either diet. Some of the WD-induced changes were similar in the KO-WD and HET-WD-fed mice, but the latter displayed a "rescued" phenotype in terms of diet-induced abnormalities in glucose tolerance, neuroinflammation, and hippocampus-dependent performance. Thus, complete versus partial Sert inactivation in aged mice results in distinct metabolic, molecular, and behavioral consequences in response to the WD. Our findings show that Sert ^+/- mice are resilient to certain environmental challenges and support the concept of heterosis as evolutionary adaptive mechanism.

Meta-analyses of the association between the PPARGC1A Gly482Ser polymorphism and athletic performance

Peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) encoded by the PPARGC1A gene is a vital regulator of glucose and fatty acid oxidation, mitochondrial biogenesis, and skeletal muscle fibre conversion. Several studies have investigated the association between PPARGC1A Gly482Ser polymorphism and athletic performance in humans. However, the results were contradictory. In the present study, two meta-analyses were performed to assess the association between the Gly482Ser polymorphism and endurance or power athletic performance to resolve this inconsistency. Ten articles were identified, including a total of 3,708 athletes and 6,228 controls. Higher frequencies of the Gly/Gly genotype (OR, 1.26; 95% CI, 1.11-1.42) and the Gly allele (OR, 1.29; 95% CI, 1.09-1.52) were observed in Caucasian endurance athletes. Furthermore, higher incidences of the Gly/Gly genotype (OR, 1.30; 95% CI, 1.16-1.46) and the Gly allele (OR, 1.22; 95% CI, 1.12-1.33) were observed in power athletes compared to controls. This finding demonstrates that the Gly/Gly genotype and the Gly allele of the PPARGC1A Gly482Ser polymorphism may facilitate athletic performance regardless of the type of sport, as well as providing solid evidence to support the possible influence of genetic factors on human athletic performance.

Peroxisome proliferator-activated receptor gamma coactivator 1α variation: a closer look at obesity onset age and its related metabolic status and body composition

There is a lack of knowledge regarding the effect of polymorphisms of the peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) gene on the age of obesity onset. Hence, 3 polymorphisms of the PGC-1α gene (PGC-1α rs17574213, rs8192678, and rs3755863) were examined in association with obesity onset age. Also, obesity onset age-related metabolic status and body composition were evaluated. This cross-sectional study was conducted with a total of 321 obese participants. Anthropometric and biochemical information, body composition, and PGC-1α gene sequences were analyzed. The rs17574213 polymorphism was associated with obesity onset in children aged <1 years and 10-18 years. The rs8192678 polymorphism was associated with obesity onset in adulthood. Body mass index, body fat percent, and trunk fat were higher in groups whose obesity began at age <1 year or 10-18 years than in other groups. Serum levels of high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and total cholesterol were lowest in the group with obesity onset between the ages of 10 and 18 years. Visceral fat and fasting blood glucose were highest in those whose obesity began in adulthood. In conclusion, 2 polymorphisms of the PGC-1α gene were associated with obesity onset age.

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.

Peroxisome proliferator-activated receptor gamma co-activator 1 gene Gly482Ser polymorphism is associated with the response of low-density lipoprotein cholesterol concentrations to exercise training in elderly Japanese

Muscle peroxisome proliferator-activated receptor gamma co-activator 1 (PGC-1)α gene expression is influenced by the Gly482Ser gene polymorphism, which is a candidate genetic risk factor for diabetes mellitus and obesity. This study investigated the effects of PGC-1 gene Gly482Ser polymorphisms on alterations in glucose and lipid metabolism induced by exercise training. A 12-week intervention study was performed for 119 participants who were more than 65 years of age and completed exercise training at lactate threshold intensity. Total cholesterol and low-density lipoprotein cholesterol were significantly reduced in Gly/Gly but not in Gly/Ser and Ser/Ser participants after exercise. The Gly/Gly genotype of the PGC-1 gene Gly482Ser polymorphism influences the effects of moderate-intensity exercise training on low-density lipoprotein cholesterol and total cholesterol concentrations in older people.

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.

Expression of candidate genes associated with obesity in peripheral white blood cells of Mexican children

INTRODUCTION

Obesity is a chronic, complex, and multifactorial disease, characterized by excess body fat. Diverse studies of the human genome have led to the identification of susceptibility genes that contribute to obesity. However, relatively few studies have addressed specifically the association between the level of expression of these genes and obesity.

MATERIAL AND METHODS

We studied 160 healthy and obese unrelated Mexican children aged 6 to 14 years. We measured the transcriptional expression of 20 genes associated with obesity, in addition to the biochemical parameters, in peripheral white blood cells. The detection of mRNA levels was performed using the OpenArray Real-Time PCR System (Applied Biosystems).

RESULTS

Obese children exhibited higher values of fasting glucose (p = 0.034), fasting insulin (p = 0.004), low-density lipoprotein (p = 0.006), triglycerides (p < 0.001), systolic blood pressure and diastolic blood pressure (p < 0.001), and lower values of high-density lipoprotein (p < 0.001) compared to lean children. Analysis of transcriptional expression data showed a difference for ADRB1 (p = 0.0297), ADIPOR1 (p = 0.0317), GHRL (p = 0.0060) and FTO (p = 0.0348) genes.

CONCLUSIONS

Our results suggest that changes in the expression level of the studied genes are involved in biological processes implicated in the development of childhood obesity. Our study contributes new perspectives for a better understanding of biological processes involved in obesity. The protocol was approved by the National Committee and Ethical Committee Board from the Mexican Social Security Institute (IMSS) (IMSS FIS/IMSS/PRIO/10/011).

Behavioral and Environmental Modification of the Genetic Influence on Body Mass Index: A Twin Study

Body mass index (BMI) has a strong genetic basis, with a heritability around 0.75, but is also influenced by numerous behavioral and environmental factors. Aspects of the built environment (e.g., environmental walkability) are hypothesized to influence obesity by directly affecting BMI, by facilitating or inhibiting behaviors such as physical activity that are related to BMI, or by suppressing genetic tendencies toward higher BMI. The present study investigated relative influences of physical activity and walkability on variance in BMI using 5079 same-sex adult twin pairs (70 % monozygotic, 65 % female). High activity and walkability levels independently suppressed genetic variance in BMI. Estimating their effects simultaneously, however, suggested that the walkability effect was mediated by activity. The suppressive effect of activity on variance in BMI was present even with a tendency for low-BMI individuals to select into environments that require higher activity levels. Overall, our results point to community- or macro-level interventions that facilitate individual-level behaviors as a plausible approach to addressing the obesity epidemic among US adults.

Elite athletes' genetic predisposition for altered risk of complex metabolic traits

BACKGROUND

Genetic variants may predispose humans to elevated risk of common metabolic morbidities such as obesity and Type 2 Diabetes (T2D). Some of these variants have also been shown to influence elite athletic performance and the response to exercise training. We compared the genotype distribution of five genetic Single Nucleotide Polymorphisms (SNPs) known to be associated with obesity and obesity co-morbidities (IGF2BP2 rs4402960, LPL rs320, LPL rs328, KCJN rs5219, and MTHFR rs1801133) between athletes (all male, n = 461; endurance athletes n = 254, sprint/power athletes n = 207), and controls (all male, n = 544) in Polish and Russian samples. We also examined the association between these SNPs and the athletes' competition level ('elite' and 'national' level). Genotypes were analysed by Single-Base Extension and Real-Time PCR. Multinomial logistic regression analyses were conducted to assess the association between genotypes and athletic status/competition level.

RESULTS

IGF2BP2 rs4402960 and LPL rs320 were significantly associated with athletic status; sprint/power athletes were twice more likely to have the IGF2BP2 rs4402960 risk (T) allele compared to endurance athletes (OR = 2.11, 95% CI = 1.03-4.30, P <0.041), and non-athletic controls were significantly less likely to have the T allele compared to sprint/power athletes (OR = 0.62, 95% CI =0.43-0.89, P <0.0009). The control group was significantly more likely to have the LPL rs320 risk (G) allele compared to endurance athletes (OR = 1.26, 95% CI = 1.05-1.52, P <0.013). Hence, endurance athletes were the "protected" group being significantly (p < 0.05) less likely to have the risk allele compared to sprint/power athletes (IGF2BP2 rs4402960) and significantly (p < 0.05) less likely to have the risk allele compared to controls (LPL rs320). The other 3 SNPs did not show significant differences between the study groups.

CONCLUSIONS

Male endurance athletes are less likely to have the metabolic risk alleles of IGF2BP2 rs4402960 and LPL rs320, compared to sprint/power athletes and controls, respectively. These results suggest that some SNPs across the human genome have a dual effect and may predispose endurance athletes to reduced risk of developing metabolic morbidities, whereas sprint/power athletes might be predisposed to elevated risk.

Resistance to high-fat diet-induced obesity in male heterozygous Pprc1 knockout mice

Peroxisome proliferator-activated receptor gamma, co-activator-related 1 (Pprc1) is the third member of the Pgc1 family. Other than the well-characterized Pgc1a and Pgc1b that act as regulators of mitochondrial biogenesis and oxidative metabolism, the function of Pprc1 in vivo is rarely reported, due to embryonic lethality of whole-body Pprc1 knockout mice. To investigate the biological and physiological function of Pprc1 in metabolic processes, male Pprc1(+/-) mice fed with a high fat diet (HFD) showed resistance to diet-induced obesity with a decrease of adipose tissue in Pprc1(+/-) mice, which was a result of elevated energy expenditure. In skeletal muscle of Pprc1(+/-) mice, Pprc1 level showed haplo-insufficiency with down-regulation of Pgc1b and Pgc1a, whereas in adipose tissue, Pprc1 expression remained normal, with significant compensatory increase of other Pgc1 family members to induce an up-regulation of respiratory chain genes. Taken together, as the first report on the metabolic roles of Pprc1 in vivo, these results indicated an elevated basal metabolic rate and lipid metabolic alteration of male Pprc1(+/-) mice on HFD, suggesting the significant role of Pprc1 in controlling mitochondrial gene expression and energy metabolic processes, synergistically with Pgc1a and Pgc1b.

Heritability and genetic etiology of habitual physical activity: a twin study with objective measures

Twin studies with objective measurements suggest habitual physical activity (HPA) are modestly to highly heritable, depending on age. We aimed to confirm or refute this finding and identify relevant genetic variants using a candidate gene approach. HPA was measured for 14 days with a validated triaxial accelerometer (Tracmor) in two populations: (1) 28 monozygotic and 24 dizygotic same-sex twin pairs (aged 22 ± 5 years, BMI 21.8 ± 3.4 kg/m(2), 21 male, 31 female pairs); (2) 52 and 65 unrelated men and women (aged 21 ± 2 years, BMI 22.0 ± 2.5 kg/m(2)). Single nucleotide polymorphisms (SNPs) in PPARD, PPARGC1A, NRF1 and MTOR were considered candidates. Association analyses were performed for both groups separately followed by meta-analysis. Structural equation modeling shows significant familiality for HPA, consistent with a role for additive genetic factors (heritability 57 %, 95 % CI 32-74 %, AE model) or common environmental factors (47 %, 95 % CI 23-65 %, CE model). A moderate heritability was observed for the time spent on low- and high-intensity physical activity (P ≤ 0.05), but could not be confirmed for the time spent on moderate-intensity physical activity. For PPARD, each additional effect allele was inversely associated with HPA (P ≤ 0.01; rs2076168 allele C) or tended to be associated with HPA (P ≤ 0.05; rs2267668 allele G). Linkage disequilibrium existed between those two SNPs (alleles A/G and A/C, respectively) and meta-analysis showed that carriers of the AA GC haplotype were less physically active than carriers of the AA AA and AA AC haplotypes combined (P = 0.017). For PPARGC1A, carriers of AA in rs8192678 spent more time on high-intensity physical activity than GG carriers (P = 0.001). No associations were observed with SNPs in NRF1 and MTOR. In conclusion, HPA may be modestly heritable, which is confirmed by an association with variants in PPARD.

Mitochondriogenesis genes and extreme longevity

Genes of the proliferator-activated receptor delta (PPARD)-peroxisome proliferator-activated receptor γ coactivator 1α (PPARGC1A, also termed PGC1-α)-nuclear respiratory factor (NRF)-mitochondrial transcription Factor A (TFAM) mitochondriogenesis pathway can influence health/disease phenotypes, yet their association with extreme longevity is not known. We studied the association of five common polymorphisms in genes of this pathway (rs2267668, rs8192678, rs6949152, rs12594956, rs1937) and extreme longevity using a case (107 centenarians)-control (284 young adults) design. We found no between-group differences in allele/genotype frequencies, except for CC genotype in rs1937 (p=0.003), with no representation in controls (0%), versus 2.8% in centenarians (2 men, 1 woman). In summary, the studied genetic variants of the PPARD-PPARGC1A-NRF-TFAM pathway were not associated with extreme longevity, yet a marginal association could exist for rs1937.

The FTO A/T polymorphism and elite athletic performance: a study involving three groups of European athletes

Objective

The FTO A/T polymorphism (rs9939609) is a strong candidate to influence obesity-related traits. Elite athletes from many different sporting disciplines are characterized by low body fat. Therefore, the aim of this study was to assess whether athletic status is associated with the FTO A/T polymorphism.

Subjects and Methods

A large cohort of European Caucasians from Poland, Russia and Spain were tested to examine the association between FTO A/T polymorphism (rs9939609) and athletic status. A total of 551 athletes were divided by type of sport (endurance athletes, n = 266 vs. sprint/power athletes, n = 285) as well as by level of competition (elite-level vs. national-level). The control group consisted of 1,416 ethnically-matched, non-athletic participants, all Europeans. Multinomial logistic regression analyses were conducted to assess the association between FTO A/T genotypes and athletic status/competition level.

Results

There were no significantly greater/lesser odds of harbouring any type of genotype when comparing across athletic status (endurance athletes, sprint/power athletes or control participants). These effects were observed after controlling for sex and nationality. Furthermore, no significantly greater/lesser odds ratios were observed for any of the genotypes in respect to the level of competition (elite-level vs. national-level).

Conclusion

The FTO A/T polymorphism is not associated with elite athletic status in the largest group of elite athletes studied to date. Large collaborations and data sharing between researchers, as presented here, are strongly recommended to enhance the research in the field of exercise genomics.

A common variant in the peroxisome proliferator-activated receptor-γ coactivator-1α gene is associated with nonalcoholic fatty liver disease in obese children

BACKGROUND

The single nucleotide polymorphism in the peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α gene (PPARGC1A) was identified to be associated with nonalcoholic fatty liver disease (NAFLD) in adults. The PPARGC1A gene encodes PGC-1α, which regulates cellular energy metabolism.

OBJECTIVE

We aimed to test the hypothesis that the PPARGC1A rs8192678 risk A allele would influence the risk of NAFLD in obese children.

DESIGN

We genotyped PPARGC1A rs8192678 and PNPLA3 rs738409 in 781 obese children aged 7-18 y. NAFLD was determined by ultrasonography. We evaluated the independent influence of the PPARGC1A rs8192678 risk A allele on pediatric NAFLD after control for the effect of the PNPLA3 rs738409 polymorphism.

RESULTS

A total of 23.3% of the recruited obese children had NAFLD. PNPLA3 rs738409 increased the OR of NAFLD by 1.622 (95% CI: 1.071, 2.457; P = 0.023) in subjects with GC alleles and 2.659 (95% CI: 1.509, 4.686; P < 0.001) for GG alleles, as compared with CC alleles. After control for the effects of age- and sex-adjusted BMI, sex, and PNPLA3 rs738409 polymorphism, the PPARGC1A rs8192678 risk A allele was an independent risk factor for developing NAFLD, with an OR of 1.740 (95% CI: 1.149, 2.637; P = 0.009). Subjects with the PPARGC1A rs8192678 risk A allele had an increase in the mean serum alanine aminotransferase concentration of 5.2 IU/L, as compared with subjects without this allele (P = 0.011).

CONCLUSION

The PPARGC1A rs8192678 risk A allele is associated with an increased risk of NAFLD, independent of the effect of the PNPLA3 rs738409 polymorphism in our population of obese Taiwanese children.

Physical activity and sex modulate obesity risk linked to 3111T/C gene variant of the CLOCK gene in an elderly population: the SUN Project

Genetic factors may interact with physical activity levels to modify obesity risk. Our aim was to explore the influence of rs1801260 single-nucleotide polymorphism (SNP) (3111T/C) of CLOCK gene on obesity risk, and to examine its potential interaction with lifestyle factors in an elderly population within the SUN ("Seguimiento Universidad de Navarra") Project. Subjects (n = 903, aged 69 ± 6 yrs) were recruited from the SUN Project. DNA was obtained from saliva, whereas lifestyle and dietary data were collected by validated self-report questionnaires. Genotype was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) plus allele discrimination. A significant interaction was observed between the 3111T/C SNP of CLOCK gene and sex for overweight/obesity risk (p for sex × CLOCK interaction <.001). Our results showed that women carrying the C allele of CLOCK gene had a marginally significant lower risk of overweight/obesity compared with noncarrier-TT-subjects (odds ratio [OR]: .61, 95% confidence interval [CI]: .36-1.04; p = .069). Moreover, this association of the C allele with a decreased overweight/obesity risk might be enhanced in those women with a high physical activity level. Women practicing more than 16.8 metabolic equivalent tasks (hours per week) had a significantly lower overweight/obesity risk (OR: .36, 95% CI: .17-.79; p = .011). Furthermore, a significant interaction between the 3111T/C gene variant and physical activity (PA) for overweight/obesity risk was observed but only in women (p for PA × CLOCK interaction <.050). In conclusion, it appears that physical activity levels may act by modifying the association of the 3111T/C SNP (rs1801260) of the CLOCK gene with overweight/obesity risk in elderly women in the SUN Project.

Associations between polymorphisms in genes involved in fatty acid metabolism and dietary fat intakes

BACKGROUND

Obesity prevalence is growing in our population. Twin studies have estimated the heritability of dietary intakes to about 30%. The objective of this study was to verify whether polymorphisms in genes involved in fatty acid metabolism are associated with dietary fat intakes.

METHODS

Seven hundred participants were recruited. A validated food frequency questionnaire was used to assess dietary intakes. PCR-RFLP and TAQMAN methodology were used to genotype PPARα Leu162Val, PPARγ Pro12Ala, PPARδ -87T>C, PPARGC1α Gly482Ser, FASN Val1483Ile and SREBF1 c.*619C>G. Statistical analyses were executed with SAS statistical package.

RESULTS

Carriers of the Ala12 allele of PPARγ Pro12Ala polymorphism had higher intakes of total fat (p = 0.04). For FASN Val1483Ile polymorphism, significant gene-sex interaction effects were found for total fat and saturated fat intakes (p = 0.02 and p = 0.002, respectively). No significant difference in fat intakes was observed for PPARα Leu162Val, PPARδ -87T>C, PPARGC1α Gly482Ser and SREBF1 c.*619C>G polymorphisms.

CONCLUSIONS

Polymorphisms in PPARγ and FASN seem to be associated with dietary fat intakes. Genetic variants are important to take into account when studying dietary intakes.

HTR1B, ADIPOR1, PPARGC1A, and CYP19A1 and obesity in a cohort of Caucasians and African Americans: an evaluation of gene-environment interactions and candidate genes

The World Health Organization estimates that the number of obese and overweight adults has increased to 1.6 billion, with concomitant increases in comorbidity. While genetic factors for obesity have been extensively studied in Caucasians, fewer studies have investigated genetic determinants of body mass index (BMI; weight (kg)/height (m)(2)) in African Americans. A total of 38 genes and 1,086 single nucleotide polymorphisms (SNPs) in African Americans (n = 1,173) and 897 SNPs in Caucasians (n = 1,165) were examined in the Southern Community Cohort Study (2002-2009) for associations with BMI and gene × environment interactions. A statistically significant association with BMI survived correction for multiple testing at rs4140535 (β = -0.04, 95% confidence interval: -0.06, -0.02; P = 5.76 × 10(-5)) in African Americans but not in Caucasians. Gene-environment interactions were observed with cigarette smoking and a SNP in ADIPOR1 in African Americans, as well as between a different SNP in ADIPOR1 and physical activity in Caucasians. A SNP in PPARGC1A interacted with alcohol consumption in African Americans, and a different SNP in PPARGC1A was nominally associated in Caucasians. A SNP in CYP19A1 interacted with dietary energy intake in African Americans, and another SNP in CYP191A had an independent association with BMI in Caucasians.

Gene × environment interactions in type 2 diabetes

People vary genetically in their susceptibility to the effects of environmental risk factors for many diseases. Genetic variation also underlies the extent to which people respond appropriately to clinical therapies. Defining the basis to the interactions between the genome and the environment may help elucidate the biologic basis to diseases such as type 2 diabetes, as well as help target preventive therapies and treatments. This review examines 1) some of the most current evidence on gene × environment interactions in relation to type 2 diabetes; 2) outlines how the availability of information on gene × environment interactions might help improve the prevention and treatment of type 2 diabetes; and 3) discusses existing and emerging strategies that might enhance our ability to detect and exploit gene × environment interactions in complex disease traits.

Genetic determinants of hepatic steatosis in man

Hepatic steatosis is one of the most common liver disorders in the general population. The main cause of hepatic steatosis is nonalcoholic fatty liver disease (NAFLD), representing the hepatic component of the metabolic syndrome, which is characterized by type 2 diabetes, obesity, and dyslipidemia. Insulin resistance and excess adiposity are considered to play key roles in the pathogenesis of NAFLD. Although the risk factors for NAFLD are well established, the genetic basis of hepatic steatosis is largely unknown. Here we review recent progress on genomic variants and their association with hepatic steatosis and discuss the potential impact of these genetic studies on clinical practice. Identifying the genetic determinants of hepatic steatosis will lead to a better understanding of the pathogenesis and progression of NAFLD.

A Database of Gene-Environment Interactions Pertaining to Blood Lipid Traits, Cardiovascular Disease and Type 2 Diabetes

As the role of the environment - diet, exercise, alcohol and tobacco use and sleep among others - is accorded a more prominent role in modifying the relationship between genetic variants and clinical measures of disease, consideration of gene-environment (GxE) interactions is a must. To facilitate incorporation of GxE interactions into single-gene and genome-wide association studies, we have compiled from the literature a database of GxE interactions relevant to nutrition, blood lipids, cardiovascular disease and type 2 diabetes. Over 550 such interactions have been incorporated into a single database, along with over 1430 instances where a lack of statistical significance was found. This database will serve as an important resource to researchers in genetics and nutrition in order to gain an understanding of which points in the human genome are sensitive to variations in diet, physical activity and alcohol use, among other lifestyle choices. Furthermore, this GxE database has been designed with future integration into a larger database of nutritional phenotypes in mind.

Genetic polymorphisms in non-alcoholic fatty liver disease: Clues to pathogenesis and disease progression

The spectrum of non-alcoholic fatty liver disease (NAFLD) ranges from simple steatosis through steatohepatitis to advanced fibrosis and cirrhosis. Although the reason why only a minority of patients develop progressive forms of disease still remains largely unclear, recent research has identified genetic factors as a possible basis for this variation in disease presentation. Most of the studies have been focused on finding associations between advanced disease forms and selected single nucleotide polymorphisms in genes encoding various proteins involved in disease pathogenesis. Although there are many limitations regarding the study design and interpretation of published data, further carefully planned studies together with implementation of new genetic technologies will likely bring new insights into disease pathogenesis and potential benefits to the management of patients with NAFLD.

The human gene map for performance and health-related fitness phenotypes: the 2006-2007 update

This update of the human gene map for physical performance and health-related fitness phenotypes covers the research advances reported in 2006 and 2007. The genes and markers with evidence of association or linkage with a performance or a fitness phenotype in sedentary or active people, in responses to acute exercise, or for training-induced adaptations are positioned on the map of all autosomes and sex chromosomes. Negative studies are reviewed, but a gene or a locus must be supported by at least one positive study before being inserted on the map. A brief discussion on the nature of the evidence and on what to look for in assessing human genetic studies of relevance to fitness and performance is offered in the introduction, followed by a review of all studies published in 2006 and 2007. The findings from these new studies are added to the appropriate tables that are designed to serve as the cumulative summary of all publications with positive genetic associations available to date for a given phenotype and study design. The fitness and performance map now includes 214 autosomal gene entries and quantitative trait loci plus seven others on the X chromosome. Moreover, there are 18 mitochondrial genes that have been shown to influence fitness and performance phenotypes. Thus,the map is growing in complexity. Although the map is exhaustive for currently published accounts of genes and exercise associations and linkages, there are undoubtedly many more gene-exercise interaction effects that have not even been considered thus far. Finally, it should be appreciated that most studies reported to date are based on small sample sizes and cannot therefore provide definitive evidence that DNA sequence variants in a given gene are reliably associated with human variation in fitness and performance traits.

The role of the PGC1α Gly482Ser polymorphism in weight gain due to intensive diabetes therapy

The Diabetes Control and Complications Trial (DCCT) involved intensive diabetes therapy of subjects with type 1 diabetes mellitus (T1DM) for an average period of 6.5 years. A subset of these subjects gained excessive weight. We tested for association of polymorphisms in 8 candidate genes with the above trait. We found the Gly482Ser polymorphism in the peroxisome proliferator-activated receptor γ coactivator-1α (PGC1α) to be significantly associated with weight gain in males (P = .0045) but not in females. The Ser allele was associated with greater weight gain than the Gly allele (P = .005). Subjects with a family history of type 2 diabetes mellitus (T2DM) were more common among those who gained excessive weight. We conclude that T2DM and the Gly482Ser polymorphism in PGC1α contribute to the effect of intensive diabetes therapy on weight gain in males with T1DM.

PPARGC1A sequence variation and cardiovascular risk-factor levels: a study of the main genetic effects and gene x environment interactions in children from the European Youth Heart Study

AIMS/HYPOTHESIS

The PPARGC1A gene coactivates multiple nuclear transcription factors involved in cellular energy metabolism and vascular stasis. In the present study, we genotyped 35 tagging polymorphisms to capture all common PPARGC1A nucleotide sequence variations and tested for association with metabolic and cardiovascular traits in 2,101 Danish and Estonian boys and girls from the European Youth Heart Study, a multicentre school-based cross-sectional cohort study.

METHODS

Fasting plasma glucose concentrations, anthropometric variables and blood pressure were measured. Habitual physical activity and aerobic fitness were objectively assessed using uniaxial accelerometry and a maximal aerobic exercise stress test on a bicycle ergometer, respectively.

RESULTS

In adjusted models, nominally significant associations were observed for BMI (rs10018239, p = 0.039), waist circumference (rs7656250, p = 0.012; rs8192678 [Gly482Ser], p = 0.015; rs3755863, p = 0.02; rs10018239, beta = -0.01 cm per minor allele copy, p = 0.043), systolic blood pressure (rs2970869, p = 0.018) and fasting glucose concentrations (rs11724368, p = 0.045). Stronger associations were observed for aerobic fitness (rs7656250, p = 0.005; rs13117172, p = 0.008) and fasting glucose concentrations (rs7657071, p = 0.002). None remained significant after correcting for the number of statistical comparisons. We proceeded by testing for gene x physical activity interactions for the polymorphisms that showed nominal evidence of association in the main effect models. None of these tests was statistically significant.

CONCLUSIONS/INTERPRETATION

Variants at PPARGC1A may influence several metabolic traits in this European paediatric cohort. However, variation at PPARGC1A is unlikely to have a major impact on cardiovascular or metabolic health in these children.

Gene-environment interaction and obesity

The epidemic of obesity has become a major public health problem. Common-form obesity is underpinned by both environmental and genetic factors. Epidemiological studies have documented that increased intakes of energy and reduced consumption of high-fiber foods, as well as sedentary lifestyle, were among the major driving forces for the epidemic of obesity. Recent genome-wide association studies have identified several genes convincingly related to obesity risk, including the fat mass and obesity associated gene and the melanocortin-4 receptor gene. Testing gene-environment interaction is a relatively new field. This article reviews recent advances in identifying the genetic and environmental risk factors (lifestyle and diet) for obesity. The evidence for gene-environment interaction, especially from observational studies and randomized intervention trials, is examined specifically. Knowledge about the interplay between genetic and environmental components may facilitate the choice of more effective and specific measures for obesity prevention based on the personalized genetic make-up.

Tooth loss and obesity in a defined Swedish population

Aims: To explore the association between tooth loss and obesity in an adult Swedish population, and to investigate the influence of socioeconomy, life-style, and co-morbidity. Methods: A cross-sectional population health survey conducted in 2001—2005 in 2816 randomly selected Swedish men and women (age: 30—74 years; participation rate 76%). Main measures were; tooth loss: < 20 remaining teeth (self-reported), general obesity: BMI≥30 kg m-2, abdominal obesity: waist circumference >88 in women and >102 cm in men. Adjustments were made for socioeconomy, life-style, and co-morbidity. Results: 420 individuals (21.2%) had < 20 remaining teeth: 30—59 years 6.0%, 60—74 years 53.5%. Mean BMI was similar in men and women (26.9 kg m-2), however, both general and abdominal obesity was still more frequent among women (both p < 0.001). There was a significant interaction between age and tooth loss in the association with both general (p = 0.004) and abdominal obesity (p < 0.011) in men. In participants below 60 years of age, the association between tooth loss and general obesity (OR 2.17 [95% CI 1.51 — 3.12]) and abdominal obesity (2.23 [1.58 — 3.15]), respectively, was statistically significant independent of age and gender, and remained so also when accounting for differences in socioeconomy, life-style, and co-morbidity. There was no similar association in those 60 years or older. The findings in men and women were robust and concordant. Conclusions: Common mechanisms for oral health and obesity should be explored more also including longitudinal designs. The findings are important for targeting comprehensive interventions against obesity and tooth loss, especially among younger adults.

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

Background

The Gly482Ser polymorphism in peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PPARGC1A) has been demonstrated to be associated with diabetes, obesity and hypertension, all of which are important risk factors for left ventricular diastolic dysfunction.

Methods

The PPARGC1A Gly482Ser polymorphism was genotyped in a community-based cohort of 499 men and 533 women, who also underwent an echocardiographic examination to determine their left ventricular diastolic function. The association between the polymorphism and the presence of diastolic dysfunction was evaluated using logistic regression models.

Results

The Ser allele of the PPARGC1A Gly482Ser polymorphism was significantly associated with a lower risk of diastolic dysfunction in men, but not in women. In a model adjusting for potential confounders (age, body mass index, leisure time physical activity, hypertension and diabetes) the results were still significant and substantial (odds ratio 0.13, 95% confidence interval 0.03–0.54, p for trend = 0.004). The results were consistent in a series of models, and they imply a multiplicative, protective effect of the Ser allele, with lower risk of diastolic dysfunction for each copy of the allele.

Conclusion

The Ser allele of the PPARGC1A Gly482Ser polymorphism was associated with decreased risk of diastolic left ventricular dysfunction in men, but not in women, in our large community-based sample. It was associated with a substantially decreased risk, even after adjustment for potential confounders. The clinical importance of the findings has to be established in further studies.

PGC-1alpha Gly482Ser polymorphism is associated with the plasma adiponectin level in type 2 diabetic men

Peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1alpha) is a multifunctional transcriptional regulator for the pathways controlling mitochondrial biogenesis, oxidative metabolism, and glucose homeostasis. Genetic studies have suggested that Gly482Ser polymorphism of the PGC-1alpha gene is associated with a higher risk of type 2 diabetes, obesity, and hypertension. Adiponectin is an antidiabetic and antiatherogenic adipocytokine that is specifically produced by adipose tissue, and the transcription of the adiponectin gene is regulated by PPARgamma. In this study, we examined the effect of Gly482Ser polymorphism on the plasma adiponectin level in Japanese type 2 diabetics. The Gly482Ser genotype was associated with a lower plasma adiponectin level in type 2 diabetic men, but not in type 2 diabetic women. The impact of this variation on the adiponectin promoter was also assessed by a reporter gene assay, but there was no significant difference between activation by the wild type and Gly482Ser- PGC-1alpha proteins, indicating that this variation itself has no functional effect. Evaluation of the pattern of linkage disequilibrium revealed that the Gly482Ser polymorphism is located in the largest linkage disequilibrium block of the PGC-1alpha gene. Therefore the observed gender-specific association between PGC-1alpha and the plasma adiponectin level may reflect linkage disequilibrium of Gly482Ser polymorphism with other causative variations.

The Gly482Ser genotype at the PPARGC1A gene and elevated blood pressure: a meta-analysis involving 13,949 individuals

The protein encoded by the PPARGC1A gene is expressed at high levels in metabolically active tissues and is involved in the control of oxidative stress via reactive oxygen species detoxification. Several recent reports suggest that the PPARGC1A Gly482Ser (rs8192678) missense polymorphism may relate inversely with blood pressure. We used conventional meta-analysis methods to assess the association between Gly482Ser and systolic (SBP) or diastolic blood pressures (DBP) or hypertension in 13,949 individuals from 17 studies, of which 6,042 were previously unpublished observations. The studies comprised cohorts of white European, Asian, and American Indian adults, and adolescents from South America. Stratified analyses were conducted to control for population stratification. Pooled genotype frequencies were 0.47 (Gly482Gly), 0.42 (Gly482Ser), and 0.11 (Ser482Ser). We found no evidence of association between Gly482Ser and SBP [Gly482Gly: mean = 131.0 mmHg, 95% confidence interval (CI) = 130.5-131.5 mmHg; Gly482Ser mean = 133.1 mmHg, 95% CI = 132.6-133.6 mmHg; Ser482Ser: mean = 133.5 mmHg, 95% CI = 132.5-134.5 mmHg; P = 0.409] or DBP (Gly482Gly: mean = 80.3 mmHg, 95% CI = 80.0-80.6 mmHg; Gly482Ser mean = 81.5 mmHg, 95% CI = 81.2-81.8 mmHg; Ser482Ser: mean = 82.1 mmHg, 95% CI = 81.5-82.7 mmHg; P = 0.651). Contrary to previous reports, we did not observe significant effect modification by sex (SBP, P = 0.966; DBP, P = 0.715). We were also unable to confirm the previously reported association between the Ser482 allele and hypertension [odds ratio: 0.97, 95% CI = 0.87-1.08, P = 0.585]. These results were materially unchanged when analyses were focused on whites only. However, statistical evidence of gene-age interaction was apparent for DBP [Gly482Gly: 73.5 (72.8, 74.2), Gly482Ser: 77.0 (76.2, 77.8), Ser482Ser: 79.1 (77.4, 80.9), P = 4.20 x 10(-12)] and SBP [Gly482Gly: 121.4 (120.4, 122.5), Gly482Ser: 125.9 (124.6, 127.1), Ser482Ser: 129.2 (126.5, 131.9), P = 7.20 x 10(-12)] in individuals <50 yr (n = 2,511); these genetic effects were absent in those older than 50 yr (n = 5,088) (SBP, P = 0.41; DBP, P = 0.51). Our findings suggest that the PPARGC1A Ser482 allele may be associated with higher blood pressure, but this is only apparent in younger adults.

Association between PPARGC1A polymorphisms and the occurrence of nonalcoholic fatty liver disease (NAFLD)

BACKGROUND

Genetic factors as well as environmental factors are important in the development of NAFLD and in this study we investigated associations between polymorphisms of peroxisome proliferators-activated receptor gamma coactivator 1alpha polymorphism (PPARGC1A) and NAFLD.

AIMS

We recruited 115 patients with biopsy-proven NAFLD, 65 with NASH and 50 with simple steatosis, and 441 healthy control subjects and investigated 15 SNPs of PPARGC1A.

RESULTS

SNP rs2290602 had the lowest p value in the dominant mode (p = 0.00095), and the odds ratio for NAFLD (95% CI) was 2.73 (1.48 - 5.06). rs2290602 was significantly associated with NAFLD even when the most conservative Bonferroni's correction was applied (p = 0.0143). The frequency of the T allele of rs2290602 was significantly higher in the NASH patients than in the control subjects (p = 0.00093, allele frequency mode), and its frequency in the NASH patients tended to be higher than in the simple steatosis patients (p = 0.09). The results of the real-time RT-PCR study showed that intrahepatic mRNA expression of PPARGC1A was lower in the TT group than in the GG or GT group at SNP rs2290602 (p = 0.0454).

CONCLUSION

This is the first study to demonstrate a significant association between genetic variations in PPARGC1A and NAFLD. This finding suggested that PPARGC1A polymorphism and lower expression of PPARGC1A mRNA in the liver are an important genetic contribution to etiology of NAFLD.

Candidate genes for obesity revealed from a C57BL/6J x 129S1/SvImJ intercross

OBJECTIVE

To identify the genes controlling body fat, we carried out a quantitative trait locus (QTL) analysis using C57BL/6J (B6) and 129S1/SvImJ (129) mice, which differ in obesity susceptibility after consuming an atherogenic diet.

METHODS

Mice were fed chow until 8 weeks and an atherogenic diet from 8 to 16 weeks; body fatness was measured by X-ray absorptiometry in 528 (B6 x 129) F(2) at 8 and 16 weeks. A high-density genome scan was performed using 508 polymorphic markers. After identifying the genetic loci, we narrowed the QTL using comparative genomics and bioinformatics.

RESULTS

The percentage of body fat was significantly linked to loci on chromosomes (Chr) 1 (22, 68 and 173 Mb), 4 (74 Mb), 5 (73 Mb), 7 (88 Mb), 8 (43 and 80 Mb), 9 (55 Mb), 11 (115 Mb) and 12 (32 Mb); three suggestive loci on Chrs 6 (76 Mb), 9 (30 Mb) and 16 (26 Mb) and two pairs of interacting loci (Chr 2 at 99.8 Mb with Chr 7; Chr 1 at 68 Mb with Chr 11). Comparative genomics narrowed the QTL intervals by 20-57% depending on the chromosome; in most cases, haplotype analysis further narrowed them by about 90%.

CONCLUSIONS

Our analysis identified 15 QTL for percentage of body fat. We narrowed the QTL using comparative genomics and haplotype analysis and suggest several candidate genes: Apcs on Chr 1, Ppargc1a on Chr 5, Ucp1 on Chr 8, Angptl6 on Chr 9 and Lpin1 on Chr 12.

What is the accurate prevalence of obesity in Sweden in the 21st century? Methodological experiences from the skaraborg project

OBJECTIVE

To examine the impact of non-response to self-reported body weight and height in health questionnaires for the estimation of obesity prevalence.

METHODS AND PROCEDURES

A cross-sectional population-based health survey in the community ofVara with 16,009 residents (in year 2002) in South-western Sweden. Participants randomly selected in strata by sex and age among residents being 30-74 years old were consecutively invited to the local health care center for a health examination, including two visits. Self-reported information on body weight and height were obtained by health questionnaires at the first visit, and measured information on both variables at the second visit. For this study 1,809 subjects (904 men and 905 women) completed both visits (participation rate 81%), and a nurse measured body weight and height of all at visit two. Participants not self-reporting body weight and/or height at the first visit were defined as non-responders.

RESULTS

Both male and female non-responders were significantly older than responders. Female non-responders had significantly higher BMI (29.8 +/- 5.8 kg/m(2)) than female responders (26.6 +/- 5.3 kg/m(2)), (P < 0.001). No similar findings were seen in men. Non-responders were more likely to be obese than responders both in men (odds ratio (OR) 2.06, 95% confidence interval (CI) 1.03-4.11) and in women (OR 2.24, 95% CI 1.25-4.02).

DISCUSSION

Non-responders to self-reported body weight and height in health questionnaires contribute to the underestimation of obesity. Measured body weight and height are to prefer when describing the accurate prevalence of obesity in populations.

Medical sequencing at the extremes of human body mass

Body weight is a quantitative trait with significant heritability in humans. To identify potential genetic contributors to this phenotype, we resequenced the coding exons and splice junctions of 58 genes in 379 obese and 378 lean individuals. Our 96-Mb survey included 21 genes associated with monogenic forms of obesity in humans or mice, as well as 37 genes that function in body weight-related pathways. We found that the monogenic obesity-associated gene group was enriched for rare nonsynonymous variants unique to the obese population compared with the lean population. In addition, computational analysis predicted a greater fraction of deleterious variants within the obese cohort. Together, these data suggest that multiple rare alleles contribute to obesity in the population and provide a medical sequencing-based approach to detect them.