Impact of the Peroxisome Proliferator Activated Receptor gamma2 Pro12Ala polymorphism on adiposity, lipids and non-insulin-dependent diabetes mellitus

Peroxisome proliferator-activated receptor γ Pro12 ala polymorphism and risk of cerebral stroke in type 2 diabetes mellitus egyptian patients

Objectives

This study aimed to analyze the association of the peroxisome proliferator activated receptor gamma (PPARγ) P12A (rs1801282) polymorphism with development of cerebral stroke in patients with type 2 diabetes mellitus.

Methods

We included 224 patients with diabetes, they were categorized into116 patients with ischemic stroke (IS) and 108 without IS, in addition to 148 healthy controls in this study. respectively. Anthropometric parameters and laboratory tests were measured. The polymorphism was detected by a PCR-RFLP method.

Results

A12 allele and A12 containing genotypes show significant higher percentage in patients with diabetes and IS in comparison to diabetes patients without IS (9.1 vs. 4.2%,16.4 vs7.4%; P = 0.044,0.044) with OR of 2.29 and 2. 449 respectively (95% CI: 1.024-5.115, 1.024-5.856) but does not withstand Bonferroni correction.

Conclusion

A12 containing genotypes and A12 allele are not associated with IR, diabetes and risk of IS development, however, significant higher BMI were observed in A12 allele carriers in the studied patients with diabetes as well as those with IS.

The Influence of FAM13A and PPAR-γ2 Gene Polymorphisms on the Metabolic State of Postmenopausal Women

Recently, we have observed two significant pandemics caused by communicable (COVID-19) and non-communicable factors (obesity). Obesity is related to a specific genetic background and characterized by immunogenetic features, such as low-grade systemic inflammation. The specific genetic variants include the presence of polymorphism of the Peroxisome Proliferator-Activated Receptors gene (PPAR-γ2; Pro12Ala, rs1801282, and C1431T, rs3856806 polymorphisms), β-adrenergic receptor gene (3β-AR; Trp64Arg, rs4994), and Family With Sequence Similarity 13 Member A gene (FAM13A; rs1903003, rs7671167, rs2869967). This study aimed to analyze the genetic background, body fat distribution, and hypertension risk in obese metabolically healthy postmenopausal women (n = 229, including 105 lean and 124 obese subjects). Each patient underwent anthropometric and genetic evaluations. The study has shown that the highest value of BMI was associated with visceral fat distribution. The analysis of particular genotypes has revealed no differences between lean and obese women except for FAM13A rs1903003 (CC), which was more prevalent in lean patients. The co-existence of the PPAR-γ2 C1431C variant with other FAM13A gene polymorphisms [rs1903003(TT) or rs7671167(TT), or rs2869967(CC)] was related to higher BMI values and visceral fat distribution (WHR > 0.85). The co-association of FAM13A rs1903003 (CC) and 3β-AR Trp64Arg was associated with higher values of systolic (SBP) and diastolic blood pressure (DBP). We conclude that the co-existence of FAM13A variants with C1413C polymorphism of the PPAR-γ2 gene is responsible for body fat amount and distribution.

The role of the PPARG (Pro12Ala) common genetic variant on type 2 diabetes mellitus risk

Background

Type 2 diabetes (T2DM) prevalence has been rapidly increasing in the last decades. T2DM pathogenesis is related to insulin resistance and beta-cell dysfunction. Peroxisome proliferator-activated receptor gamma (PPARG) is concerned about T2DM risk through the involvement in adipocyte differentiation and energy homeostasis. The present study aimed to find the risk associated with a common genetic variant (Pro12Ala) of the PPARG gene in the development of T2DM in a group of the Iranian population.

Methods

Totally, 149 patients with T2DM and 96 healthy individuals were recruited in this case-control study. The genotyping of the genetic variant was carried out using the polymerase chain reaction (PCR) followed by Sanger sequencing.

Results

No significant difference is observed between the CG and GG genotypes frequency of the PPARG variant (P = 0.17) in T2DM patient and the control groups. Furthermore, the frequency of the G allele was similar between case and control groups. The Pro12Ala variant may decrease the risk of diabetic retinopathy (DR) which was not statistically significant. Furthermore, the Pro12Ala variant caused a 27% increase in the risk of diabetes nephropathy (DN) among patients with T2DM but was not significant.

Conclusions

Our findings showed that the PPARG variant could not impact on T2DM development and its complications.

PPARγ2 Pro12Ala Polymorphism is Associated in Children With Traits Related to Susceptibility to Type 2 Diabetes

Peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated nuclear receptor that regulates glucose and lipid metabolism. Pharmacological activators of PPARγ are being used as a treatment of obesity related disorders such as dyslipidaemia and type 2 diabetes, but questions remain open regarding the effects of PPARγ on traits related to the development of type 2 diabetes. In our study, we have analyzed the relationship of the common variant Pro12Ala in the human PPARγ2 gene with the presence of obesity and with insulin, HOMA and lipid profile in a representative sample of 6-to 8-year-old children free from the confounding factors associated with adults. We found that Ala12Ala genotype was significantly more frequent in females with obesity than in those without obesity, with Ala12Ala carriers having significantly higher weight and body mass index (BMI), however the association disappeared when adjusting by leptin concentrations. The Ala12Ala genotype was associated with significantly higher HDL-cholesterol and apoA-I levels in males but not in females, independently of BMI. In a recessive model, in females, leptin levels appeared higher in Ala12Ala carriers. Although no apparent differences were observed in any sex when analyzing insulin levels and HOMA among genotypes without adjusting, lower insulin levels and lower HOMA appeared associated with Ala12Ala carriers when adjusting for BMI and leptin levels. In summary, our data showed that leptin seems to be having an effect on the association between the PPARγ2 Pro12Ala and BMI. Besides, after controlling for BMI and leptin, a protective effect of the Ala12Ala variant of the PPARγ2 Pro12Ala polymorphism on insulin sensitivity is evident already in prepubertal children.

High Expression Level of PPARγ in CD24 Knockout Mice and Gender-Specific Metabolic Changes: A Model of Insulin-Sensitive Obesity

Background: The heat-stable HSA/CD24 gene encodes a protein that shows high expression levels in adipocyte precursor cells but low levels in terminally differentiated adipocytes. Its high expression in many types of human cancer suggests an association between cancer, diabetes, and obesity, which is currently unclear. In addition, peroxisome proliferator-activated receptor gamma (PPARγ) is a regulator of adipogenesis that plays a role in insulin sensitivity, lipid metabolism, and adipokine expression in adipocytes. Aim: To assess gender-dependent changes in CD24 KO and its association with PPARγ expression. Experimental approach: WT and CD24 KO mice were monitored from birth up to 12 months, and various physiological and molecular characteristics were analysed. Mean body weight and adipose mass were higher in KO mice than in WT mice. Male, but not female, KO mice showed increased insulin sensitivity, glucose uptake, adipocyte size, and PPARγ expression than WT mice. In addition, enteric bacterial populations, assessed through high-throughput sequencing of stool 16S rRNA genes, were significantly different between male KO and WT mice. Conclusions: CD24 may negatively regulate PPARγ expression in male mice. Furthermore, the association between the CD24 and insulin sensitivity suggests a possible mechanism for diabetes as a cancer risk factor. Finally, CD24 KO male mice may serve as a model of obesity and insulin hyper-sensitivity.

PPARG (Pro12Ala) genetic variant and risk of T2DM: a systematic review and meta-analysis

Type 2 diabetes mellitus (T2DM) is a complex disease caused by the interaction between genetic and environmental factors. A growing number of evidence suggests that the peroxisome proliferator-activated receptor gamma (PPARG) gene plays a major role in T2DM development. Meta-analysis of genetic association studies is an efficient tool to gain a better understanding of multifactorial diseases and potentially to provide valuable insights into gene-disease interactions. The present study was focused on assessing the association between Pro12Ala variation in the PPARG and T2DM risk through a comprehensive meta-analysis. We searched PubMed, WoS, Embase, Scopus and ProQuest from 1990 to 2017. The fixed-effect or random-effect model was used to evaluate the pooled odds ratios (ORs) and 95% confidence intervals (CIs) depending on the heterogeneity among studies. The sources of heterogeneity and publication bias among the included studies were assessed using I² statistics and Egger's tests. A total of 73 studies, involving 62,250 cases and 69,613 controls were included. The results showed that the minor allele (G) of the rs1801282 variant was associated with the decreased risk of T2DM under different genetic models. Moreover, the protective effect of minor allele was detected to be significantly more in some ethnicities including the European (18%), East Asian (20%), and South East Asian (18%). And the reduction of T2DM risk in Ala12 carriers was stronger in individuals from North Europe rather than Central and South Europe. Our findings indicated that the rs1801282 variant may contribute to decrease of T2DM susceptibility in different ancestries.

Pro12Ala PPAR-γ2 and +294T/C PPAR-δ Polymorphisms and Association with Metabolic Traits in Teenagers from Northern Mexico

Peroxisome proliferator-activated receptors (PPARs) play roles in glucose and lipid metabolism regulation. Pro12Ala PPAR-γ2 and +294T/C PPAR-δ have been associated with dyslipidemia, hyperglycemia and high body mass index (BMI). We compared metabolic traits and determined associations with Pro12Ala PPAR-γ2 or +294T/C PPAR-δ polymorphism among teenagers from different ethnicity. Four hundred and twelve samples with previous biochemical and biometric measurements were used. Genomic DNA from peripheral blood was extracted and analyzed by end-point PCR for Pro12Ala PPAR-γ2. The +294T/C PPAR-δ PCR product was also digested with Bsl I. Two genotype groups were formed: major allele homozygous and minor allele carriers. Pro12Ala PPAR-γ2 G minor allele frequencies were: 10% in Mestizo-1, 19% in Mestizo-2, 23% in Tarahumara, 12% in Mennonite, and 17% in the total studied population. The +294T/C PPAR-δ C minor allele frequencies were: 18% in Mestizo-1, 20% in Mestizo-2, 6% in Tarahumara, 13% in Mennonite, and 12% in the total studied population. Teenagers with PPAR-γ2 G allele showed a greater risk for either high waist/height ratio or low high-density lipoprotein; and, also had lower total cholesterol. Whereas, PPAR-γ2 G allele showed lower overweight/obesity phenotype (BMI Z-score) frequency, PPAR-δ C allele was a risk factor for it. Metabolic traits were associated with both PPAR polymorphisms.

Association between PPARG genetic polymorphisms and ischemic stroke risk in a northern Chinese Han population: a case-control study

Two common polymorphisms of the peroxisome proliferator-activated receptor gamma (PPARG) gene, rs1801282 and rs3856806, may be important candidate gene loci affecting the susceptibility to ischemic stroke. This case-control study sought to identify the relationship between these two single-nucleotide polymorphisms and ischemic stroke risk in a northern Chinese Han population. A total of 910 ischemic stroke participants were recruited from the First Hospital of China Medical University, Shenyang, China as a case group, of whom 895 completed the study. The 883 healthy controls were recruited from the Health Check Center of the First Hospital of China Medical University, Shenyang, China. All participants or family members provided informed consent. The study protocol was approved by the Ethics Committee of the First Hospital of China Medical University, China on February 20, 2012 (approval No. 2012-38-1). The protocol was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR-COC-17013559). Plasma genomic DNA was extracted from all participants and analyzed for rs1801282 and rs3856806 single nucleotide polymorphisms using a SNaPshot Multiplex sequencing assay. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression to estimate the association between ischemic stroke and a particular genotype. Results demonstrated that the G allele frequency of the PPARG gene rs1801282 locus was significantly higher in the case group than in the control group (P < 0.001). Individuals carrying the G allele had a 1.844 fold increased risk of ischemic stroke (OR = 1.844, 95% CI: 1.286-2.645, P < 0.001). Individuals carrying the rs3856806 T allele had a 1.366 fold increased risk of ischemic stroke (OR = 1.366, 95% CI: 1.077-1.733, P = 0.010). The distribution frequencies of the PPARG gene haplotypes rs1801282-rs3856806 in the control and case groups were determined. The frequency of distribution in the G-T haplotype case group was significantly higher than that in the control group. The risk of ischemic stroke increased to 2.953 times in individuals carrying the G-T haplotype (OR = 2.953, 95% CI: 2.082-4.190, P < 0.001). The rs1801282 G allele and rs3856806 T allele had a multiplicative interaction (OR = 3.404, 95% CI: 1.631-7.102, P < 0.001) and additive interaction (RERI = 41.705, 95% CI: 14.586-68.824, AP = 0.860; 95% CI: 0.779-0.940; S = 8.170, 95% CI: 3.772-17.697) on ischemic stroke risk, showing a synergistic effect. Of all ischemic stroke cases, 86% were attributed to the interaction of the G allele of rs1801282 and the T allele of rs3856806. The effect of the PPARG rs1801282 G allele on ischemic stroke risk was enhanced in the presence of the rs3856806 T allele (OR = 8.001 vs. 1.844). The effect of the rs3856806 T allele on ischemic stroke risk was also enhanced in the presence of the rs1801282 G allele (OR = 2.546 vs. 1.366). Our results confirmed that the G allele of the PPARG gene rs1801282 locus and the T allele of the rs3856806 locus may be independent risk factors for ischemic stroke in the Han population of northern China, with a synergistic effect between the two alleles.

ASSOCIATION OF THE HUMAN PPARγ2 PRO12ALA POLYMORPHISM WITH OBESITY IN A POPULATION FROM TURKEY

BACKGROUND

There have been a number of reports on the relationship between the PPARγ2 Pro12Ala genotype and the development of obesity.

OBJECTIVE

A case-control survey was designed to investigate the potential association between a Pro12Ala polymorphism in the PPARγ2 gene and obesity and/or obesity-related phenotypes in a population from Turkey.

MATERIALS AND METHODS

The polymerase chain reaction and restriction enzyme digestion were used to genotype the Pro12Ala polymorphism of the PPARγ2 gene in 149 unrelated obese and 105 non-obese control subjects from Turkey. The data were analyzed statistically.

RESULTS

We found that the overall minor allele frequency was 0.12 in cases and 0.095 in controls. In terms of genotype distribution and allele frequencies among the cases versus controls in the population studied, only the gender-stratified analysis revealed a significantly higher frequency of Pro/Ala genotype within males. The polymorphism was associated with significantly higher weight, height, waist circumference, central adiposity (waist-to-hip ratio, WHR), lean body weight as well as dry body weight, but not overall adiposity (total body fat percentage, TBF) in cases carrying Ala allele (Pro/Ala or Ala/Ala). However, in the subjects carrying Ala allele of the control group, WHR values were found significantly lower.

CONCLUSION

Our results showed that the Pro12Ala polymorphism in the PPARγ2 gene is associated with obesity in the studied adult population from Turkey. These data suggest that the Pro12Ala polymorphism in PPARγ2 may be a potential genetic risk factor for central obesity.

Genotype-based recall to study metabolic effects of genetic variation: a pilot study of PPARG Pro12Ala carriers

AIM

To assess practical implications of genotype-based recall (GBR) studies, an increasingly popular approach for in-depth characterization of genotype-phenotype relationships.

METHODS

We genotyped 2500 participants from the Swedish EpiHealth cohort and considered loss-of-function and missense variants in genes with relation to cardiometabolic traits as the basis for our GBR study. Therefore, we focused on carriers and non-carriers of the PPARG Pro12Ala (rs1801282) variant, as it is a relatively common variant with a minor allele frequency (MAF) of 0.14. It has also been shown to affect ligand binding and transcription, and carriage of the minor allele (Ala12) is associated with a reduced risk of type 2 diabetes. We re-invited 39 Pro12Pro, 34 Pro12Ala, and 30 Ala12Ala carriers and performed detailed anthropometric and serological assessments.

RESULTS

The participation rates in the GBR study were 31%, 44%, and 40%, and accordingly we included 12, 15, and 13 individuals with Pro12Pro, Pro12Ala, and Ala12Ala variants, respectively. There were no differences in anthropometric or metabolic variables among the different genotype groups.

CONCLUSIONS

Our report highlights that from a practical perspective, GBR can be used to study genotype-phenotype relationships. This approach can prove to be a valuable tool for follow-up findings from large-scale genetic discovery studies by undertaking detailed phenotyping procedures that might not be feasible in large studies. However, our study also illustrates the need for a larger pool of genotyped or sequenced individuals to allow for selection of rare variants with larger effects that can be examined in a GBR study of the present size.

Impact of the PPAR gamma-2 gene polymorphisms on the metabolic state of postmenopausal women

The relationship Pro12Ala (rs1801282) and C1431T (rs3856806) polymorphisms of PPAR gamma-2 with glucose and lipid metabolism is not clear after menopause. We investigated the impact of the Pro12Ala and C1431T silent substitution in the 6th exon in PPAR gamma-2 gene on nutritional and metabolic status in 271 postmenopausal women (122 lean and 149 obese). The general linear model (GLM) approach to the two-way analysis of variance (ANOVA) was used to infer the interactions between the analysed genotypes. The frequency of the Pro-T haplotype was higher in obese than in lean women (p less than 0.0349). In the analysed GLM models according to obesity status, the C1431C genotype was related to a lower glucose concentration (beta=-0.2103) in lean women, and to higher folliculotropic hormone FSH levels (beta=0.1985) and lower waist circumferences (beta=-0.1511) in obese women. The influence of C1431C was present regardless of the occurrence of the Pro12Ala polymorphism. The co-existence of the C1431C and Pro12Pro genotypes was related to lower values for triceps skinfold thickness compared those for the T1241/X and Ala12/X polymorphisms (beta=-0.1425). The presence of C1431C decreased the differences between triceps values that were determined by Pro or Ala allele. In conclusion, C1431T polymorphism seems to have a more essential influence on anthropometric and biochemical parameters than is the case with Pro12Ala polymorphism.

Whole-genome association analysis of pork meat pH revealed three significant regions and several potential genes in Finnish Yorkshire pigs

Background

One of the most commonly used quality measurements of pork is pH measured 24 h after slaughter. The most probable mode of inheritance for this trait is oligogenic with several known major genes, such as PRKAG3. In this study, we used whole-genome SNP genotypes of over 700 AI boars; after a quality check, 42,385 SNPs remained for association analysis. All the boars were purebred Finnish Yorkshire. To account for relatedness of the animals, a pedigree-based relationship matrix was used in a mixed linear model to test the effect of SNPs on pH measured from loin. A bioinformatics analysis was performed to identify the most promising genes in the significant regions related to meat quality.

Results

Genome-wide association study (GWAS) revealed three significant chromosomal regions: one on chromosome 3 (39.9 Mb–40.1 Mb) and two on chromosome 15 (58.5 Mb–60.5 Mb and 132 Mb–135 Mb including PRKAG3). A conditional analysis with a significant SNP in the PRKAG3 region, MARC0083357, as a covariate in the model retained the significant SNPs on chromosome 3. Even though linkage disequilibrium was relatively high over a long distance between MARC0083357 and other significant SNPs on chromosome 15, some SNPs retained their significance in the conditional analysis, even in the vicinity of PRKAG3. The significant regions harbored several genes, including two genes involved in cyclic AMP (cAMP) signaling: ADCY9 and CREBBP. Based on functional and transcription factor-gene networks, the most promising candidate genes for meat pH are ADCY9, CREBBP, TRAP1, NRG1, PRKAG3, VIL1, TNS1, and IGFBP5, and the key transcription factors related to these genes are HNF4A, PPARG, and Nkx2-5.

Conclusions

Based on SNP association, pathway, and transcription factor analysis, we were able to identify several genes with potential to control muscle cell homeostasis and meat quality. The associated SNPs can be used in selection for better pork. We also showed that post-GWAS analysis reveals important information about the genes’ potential role on meat quality. The gained information can be used in later functional studies.

Nutrigenomic Functions of PPARs in Obesogenic Environments

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that mediate the effects of several nutrients or drugs through transcriptional regulation of their target genes in obesogenic environments. This review consists of three parts. First, we summarize current knowledge regarding the role of PPARs in governing the development of white and brown/beige adipocytes from uncommitted progenitor cells. Next, we discuss the interactions of dietary bioactive molecules, such as fatty acids and phytochemicals, with PPARs for the modulation of PPAR-dependent transcriptional activities and metabolic consequences. Lastly, the effects of PPAR polymorphism on obesity and metabolic outcomes are discussed. In this review, we aim to highlight the critical role of PPARs in the modulation of adiposity and subsequent metabolic adaptation in response to dietary challenges and genetic modifications. Understanding the changes in obesogenic environments as a consequence of PPARs/nutrient interactions may help expand the field of individualized nutrition to prevent obesity and obesity-associated metabolic comorbidities.

The PPARγ2 P12A polymorphism is not associated with all-cause mortality in patients with type 2 diabetes mellitus

The high mortality risk of patients with type 2 diabetes mellitus may well be explained by the several comorbidities and/or complications. Also the intrinsic genetic component predisposing to diabetes might have a role in shaping the risk of diabetes-related mortality. Among type 2 diabetes mellitus SNPs, rs1801282 is of particular interest because (i) it is harbored by peroxisome proliferator-activated receptor-γ2 (PPARγ2), which is the target for thiazolidinediones which are used as antidiabetic drugs, decreasing all-cause mortality in type 2 diabetes mellitus, and (ii) it is associated with insulin resistance and related traits, risk factors for overall mortality in type 2 diabetes mellitus. We investigated the role of PPARγ2 P12A, according to a dominant model (PA + AA vs. PP individuals) on incident all-cause mortality in three cohorts of type 2 diabetes mellitus, comprising a total of 1672 patients (462 deaths) and then performed a meta-analysis of ours and all available published data. In the three cohorts pooled and analyzed together, no association between PPARγ2 P12A and all-cause mortality was observed (HR 1.02, 95 % CI 0.79-1.33). Similar results were observed after adjusting for age, sex, smoking habits, and BMI (HR 1.09, 95 % CI 0.83-1.43). In a meta-analysis of ours and all studies previously published (n = 3241 individuals; 666 events), no association was observed between PPARγ2 P12A and all-cause mortality (HR 1.07, 95 % CI 0.85-1.33). Results from our individual samples as well as from our meta-analysis suggest that the PPARγ2 P12A does not significantly affect all-cause mortality in patients with type 2 diabetes mellitus.

Obesity and Pro12Ala Polymorphism of Peroxisome Proliferator-Activated Receptor-Gamma Gene in Healthy Adults: A Systematic Review and Meta-Analysis

BACKGROUND

The aim of this systematic review was to evaluate the relationship between obesity and peroxisome proliferator-activated receptor-gamma (PPARx03B3;) Pro12Ala polymorphism in healthy adults.

SUMMARY

Weighted mean differences (WMDs) of body mass index (BMI) were calculated for different inheritance models and subgroups. Fifty-six studies were eligible for inclusion in the meta-analysis. The result shows that the Ala allele of this polymorphism was associated with increased WMD in mean BMI (WMD = 0.29, 95% CI 0.10-0.48, p = 0.003). The Ala carriers were associated with increased WMD in mean BMI values in both genders and in the Caucasian subgroup. The associations were seen among people with higher levels of BMI (BMI ≥35).

MESSAGE

The Ala allele of the PPARx03B3; Pro12Ala polymorphism in healthy adults was associated with increased BMI under a dominant model of inheritance.

Variation in PPARG is associated with longitudinal change in insulin resistance in Mexican Americans at risk for type 2 diabetes

CONTEXT

Peroxisome proliferator-activated receptor gamma (PPARG) is a susceptibility locus for type 2 diabetes mellitus (T2DM). Although cross-sectional associations have been reported, primarily for Pro12Ala, few longitudinal studies in nondiabetic populations have been conducted.

OBJECTIVE

This study aimed to examine whether and to what extent variation in PPARG is associated with longitudinal changes in anthropometric and metabolic traits in Mexican Americans at risk for T2DM.

SETTING AND DESIGN

Subjects were participants of BetaGene, a family-based study of obesity, insulin resistance, and β-cell function, who completed a baseline and follow-up study visit (n = 378; mean followup, 4.6 ± 1.5 y). Phenotypes included body fat assessed by dual-energy x-ray absorptiometry; insulin sensitivity (SI), acute insulin response, and β-cell function (disposition index; DI) were estimated from iv glucose tolerance tests with Minimal Model analysis. Eighteen tag single nucleotide polymorphisms (SNPs) capturing variation in a 156-kb region surrounding PPARG were tested for association with changes in longitudinal traits. P-values were Bonferroni-corrected for multiple testing.

RESULTS

Six SNPs (rs2972164, rs11128598, rs17793951, rs1151996, rs1175541, rs3856806) were significantly associated with rate of change in SI after adjustment for age, sex, and body fat percentage, but not with changes in adiposity. rs17793951 also had a significant effect on change in DI over time. Association between rs1175541 and change in SI varied by changes in adiposity such that only carriers of the minor allele who reduced body fat over followup improved SI. rs1306470 (captured Pro12Ala, r(2) = 0.9) was not associated with rates of change in any traits and its effects were not modified by changes in adiposity.

CONCLUSIONS

Variation in PPARG, but not Pro12Ala, contributes to declining SI and concomitant deterioration in β-cell function in Mexican Americans at risk for T2DM.

The Pro12Ala Polymorphism of the Peroxisome Proliferator-Activated Receptor Gamma Gene Modifies the Association of Physical Activity and Body Mass Changes in Polish Women

Peroxisome proliferator-activated receptor γ is a key regulator of adipogenesis, responsible for fatty acid storage and maintaining energy balance in the human body. Studies on the functional importance of the PPARG Pro12Ala polymorphic variants indicated that the observed alleles may influence body mass measurements; however, obtained results were inconsistent. We have decided to check if body mass changes observed in physically active participants will be modulated by the PPARG Pro12Ala genotype. The genotype distribution of the PPARG Pro12Ala allele was examined in a group of 201 Polish women measured for selected body mass variables before and after the completion of a 12-week training program. The results of our experiment suggest that PPARG genotype can modulate training-induced body mass measurements changes: after completion of the training program, Pro12/Pro12 homozygotes were characterised by a greater decrease of body fat mass measurements in comparison with 12Ala allele carriers. These results indicate that the PPARG 12Ala variant may impair the training-induced positive effects on body mass measurements; however, the detailed mechanism of such interaction remained unclear and observed correlation between PPARG genotype and body mass differential effects should be interpreted with caution.

Epigenetic effects of human breast milk

A current aim of nutrigenetics is to personalize nutritional practices according to genetic variations that influence the way of digestion and metabolism of nutrients introduced with the diet. Nutritional epigenetics concerns knowledge about the effects of nutrients on gene expression. Nutrition in early life or in critical periods of development, may have a role in modulating gene expression, and, therefore, have later effects on health. Human breast milk is well-known for its ability in preventing several acute and chronic diseases. Indeed, breastfed children may have lower risk of neonatal necrotizing enterocolitis, infectious diseases, and also of non-communicable diseases, such as obesity and related-disorders. Beneficial effects of human breast milk on health may be associated in part with its peculiar components, possible also via epigenetic processes. This paper discusses about presumed epigenetic effects of human breast milk and components. While evidence suggests that a direct relationship may exist of some components of human breast milk with epigenetic changes, the mechanisms involved are still unclear. Studies have to be conducted to clarify the actual role of human breast milk on genetic expression, in particular when linked to the risk of non-communicable diseases, to potentially benefit the infant's health and his later life.

The Rate of Decline of Glomerular Filtration Rate May Not Be Associated with Polymorphism of the PPARγ2 Gene in Patients with Type 1 Diabetes and Nephropathy

The aim of the study was to investigate whether a Pro12Ala polymorphism in the peroxisome proliferator-activated receptor gamma 2 (PPARγ2) gene is associated with the progress of diabetic nephropathy in patients with type 1 diabetes. 197 Caucasian patients with type 1 diabetes and ethnically matched 151 normal healthy controls were genotyped for this polymorphism. Results showed that there were no significant differences in the frequencies of the genotypes and alleles of the polymorphism between groups. Multiple regression analysis in 77 patients demonstrated that the rate of decline in renal function in terms of glomerular filtration rate was significantly correlated to the baseline level of cholesterol (P = 0.0014), mean diastolic blood pressure during follow-up period (P = 0.019), and baseline level of HbA1c (P = 0.022) adjusting for the effect of diabetes duration and gender, but no significant association was found between the polymorphism and the progression of diabetic nephropathy in our studied population. In summary, our results show that the PPARγ2 polymorphism is unlikely to be associated with the development and progression of the diabetic nephropathy in patients with type 1 diabetes. Further studies in different populations may be warranted to confirm our findings as the sample size in our study was relatively small.

Diet and our genetic legacy in the recent anthropocene: a Darwinian perspective to nutritional health

Nutrient-gene research tends to focus on human disease, although such interactions are often a by-product of our evolutionary heritage. This review explores health in this context, reframing genetic variation/epigenetic phenomena linked to diet in the framework of our recent evolutionary past. This "Darwinian/evolutionary medicine" approach examines how diet helped us evolve among primates and to adapt (or fail to adapt) our metabolome to specific environmental conditions leading to major diseases of civilization. This review presents updated evidence from a diet-gene perspective, portraying discord that exists with respect to health and our overall nutritional, cultural, and activity patterns. While Darwinian theory goes beyond nutritional considerations, a significant component within this concept does relate to nutrition and the mismatch between genes, modern diet, obesogenic lifestyle, and health outcomes. The review argues that nutritional sciences should expand knowledge on the evolutionary connection between food and disease, assimilating it into clinical training with greater prominence.

The effect of PPARG gene polymorphisms on the risk of coronary heart disease: a meta-analysis

The peroxisome proliferator-activated receptor-γ (PPARG) is a member of the nuclear hormone receptor superfamily that has attracted considerable attention as a candidate gene for coronary heart disease (CHD) based on its function as a key factor involved in the regulation of lipid and glucose metabolism. In the past decade, a number of case-control studies have been carried out to investigate the relationship between the PPARG polymorphisms and CHD. However, these studies have yielded contradictory results. To derive a more precise estimation of the relationship, a meta-analysis of 33 studies including a total of 12,340 cases and 17,471 controls on 3 PPARG polymorphisms (Pro12Ala, C161T and C1431T) was performed. In a combined analysis, the summary per-allele odds ratio for CHD was 1.02 (95 % CI: 0.93-1.13), 0.86 (95 % CI: 0.72-1.02), and 0.92 (95 % CI: 0.74-1.16) for PPARG 12Ala, 161T and 1431T alleles, respectively. No significant results were observed under dominant or recessive genetic models for these polymorphisms in almost all comparisons. In the stratified analyses according to ethnicity, sample size, CHD endpoints and HWE status, no evidence of any gene-disease association was obtained. Our results suggest that the Pro12Ala, C161T and C1431T polymorphisms of PPARG gene are not associated with CHD susceptibility.

The Human Obesity Gene Map: The 2003 Update

This is the tenth update of the human obesity gene map, incorporating published results up to the end of October 2003 and continuing the previous format. Evidence from single-gene mutation obesity cases, Mendelian disorders exhibiting obesity as a clinical feature, quantitative trait loci (QTLs) from human genome-wide scans and animal crossbreeding experiments, and association and linkage studies with candidate genes and other markers is reviewed. Transgenic and knockout murine models relevant to obesity are also incorporated (N = 55). As of October 2003, 41 Mendelian syndromes relevant to human obesity have been mapped to a genomic region, and causal genes or strong candidates have been identified for most of these syndromes. QTLs reported from animal models currently number 183. There are 208 human QTLs for obesity phenotypes from genome-wide scans and candidate regions in targeted studies. A total of 35 genomic regions harbor QTLs replicated among two to five studies. Attempts to relate DNA sequence variation in specific genes to obesity phenotypes continue to grow, with 272 studies reporting positive associations with 90 candidate genes. Fifteen such candidate genes are supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. Overall, more than 430 genes, markers, and chromosomal regions have been associated or linked with human obesity phenotypes. The electronic version of the map with links to useful sites can be found at http://obesitygene.pbrc.edu.

The Human Obesity Gene Map: The 2004 Update

This paper presents the eleventh update of the human obesity gene map, which incorporates published results up to the end of October 2004. Evidence from single-gene mutation obesity cases, Mendelian disorders exhibiting obesity as a clinical feature, transgenic and knockout murine models relevant to obesity, quantitative trait loci (QTLs) from animal cross-breeding experiments, association studies with candidate genes, and linkages from genome scans is reviewed. As of October 2004, 173 human obesity cases due to single-gene mutations in 10 different genes have been reported, and 49 loci related to Mendelian syndromes relevant to human obesity have been mapped to a genomic region, and causal genes or strong candidates have been identified for most of these syndromes. There are 166 genes which, when mutated or expressed as transgenes in the mouse, result in phenotypes that affect body weight and adiposity. The number of QTLs reported from animal models currently reaches 221. The number of human obesity QTLs derived from genome scans continues to grow, and we have now 204 QTLs for obesity-related phenotypes from 50 genome-wide scans. A total of 38 genomic regions harbor QTLs replicated among two to four studies. The number of studies reporting associations between DNA sequence variation in specific genes and obesity phenotypes has also increased considerably with 358 findings of positive associations with 113 candidate genes. Among them, 18 genes are supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. Overall, >600 genes, markers, and chromosomal regions have been associated or linked with human obesity phenotypes. The electronic version of the map with links to useful publications and genomic and other relevant sites can be found at http://obesitygene.pbrc.edu.

Ala/Ala genotype of Pro12Ala polymorphism in the peroxisome proliferator-activated receptor-γ2 gene is associated with obesity and insulin resistance in Asian Indians

AIM

We determined the association of the Pro12Ala polymorphism of the peroxisome proliferator activated receptor (PPAR)-γ2 gene with obesity, insulin resistance (IR), and lipids in Asian Indians without diabetes in north India.

SUBJECTS AND METHODS

In this cross-sectional study (n = 495; 279 males and 216 females, 18-60 years of age), anthropometric (body mass index, waist and hip circumferences, and skinfold thickness) and biochemical (fasting glucose, lipid profile, fasting insulin, leptin, and adiponectin) parameters were assessed. Polymerase chain reaction-restriction fragment length polymorphism analysis was used for identification of individual genotypes.

RESULTS

Frequencies of the Pro and Ala alleles were 0.89 and 0.11, respectively. The genotype frequencies (%) of Pro/Pro, Pro/Ala, and Ala/Ala were 82.6, 14.7, and 2.7, respectively, without any gender differences. The frequency of the Ala/Ala genotype was higher in obese than in nonobese subjects (4.9% vs. 1.5%, P = 0.06). The Ala/Ala genotype was associated with higher values of hip circumference, subscapular skinfold thickness, and sum of four skinfold thickness than the Pro/Pro and Pro/Ala genotypes (P<0.05). Using a multivariate logistic regression model after adjusting for age, sex, and insulin, subjects with the Ala/Ala genotype showed a high risk of obesity (odds ratio [OR], 3.2, 95% confidence interval [CI] 1.2-12.9) and IR (OR, 3.6, 95% CI: 1.04-12.4).

CONCLUSION

The Ala/Ala genotype of the PPAR-γ2 gene is associated with obesity and IR in Asian Indians without diabetes living in north India.

Association between PPARγ2 Pro12Ala polymorphism and myocardial infarction and obesity in Han Chinese in Hohhot, China

Activation of the peroxisome proliferator-activated receptor g (PPARg) improves insulin sensitivity and inhibits atherosclerosis. Whether PPARg2 Pro12Ala polymorphism affects myocardial infarction is not clearly understood. We investigated a possible association of PPARg2 Pro12Ala polymorphism with obesity and myocardial infarction in Han Chinese in Hohhot, Inner Mongolia, China. We included 121 subjects with myocardial infarction and 137 healthy controls in our study. Triglycerides, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were measured. The following information was recorded for each subject: age, gender, body height, body weight, systolic blood pressure, and diastolic blood pressure; the body mass index was calculated. PCR-RFLP was used to examine Pro12Ala polymorphism. There were significant differences in clinical characteristics between myocardial infarction patients and healthy controls, except for diastolic blood pressure and triglycerides. The PP, PA/AA genotype frequencies were 88.4 and 11.6% in myocardial infarction patients and 95.6 and 4.4% in controls, respectively (P = 0.031). Individuals with the A allele had a significantly higher risk of myocardial infarction. The A allele was not an independent risk factor for obesity. We conclude that PPARg2 Pro12Ala polymorphisms are associated with increased risk for myocardial infarction in Han Chinese in Hohhot.

Association of PPAR-γ gene polymorphisms with obesity and obesity-associated phenotypes in North Indian population

OBJECTIVES

The worldwide increasing prevalence of obesity is considered as a major health problem. Peroxisome proliferator-activated receptor gamma (PPAR-γ) controls adipocyte differentiation and regulates a number of genes associated with energy homeostasis. In this study, we investigated the association of PPAR-γ gene Pro12Ala (rs1801282) and C1431T (rs3856806) polymorphisms with morbid obesity and related phenotypes, in north Indian population.

METHODS

A total of 6,42 subjects, 309, obese and 333 nonobese individuals were included in this case-control study. Insulin, adiponectin, glucose, and lipid levels were estimated using standard protocols. All subjects were genotyped by PCR restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

The ProAla+AlaAla genotypes of PPAR-γ Pro12Ala were significantly associated with higher risk of obesity while C1431T polymorphism did not show any significant association. None of the haplotypes showed association with morbid obesity. However, a strong association of variant genotypes was observed with higher levels of insulin, HOMA-IR, and lower serum adiponectin concentrations.

CONCLUSION

PPAR-γ gene polymorphisms influence obesity and obesity phenotype in a complex manner, probably involving insulin resistance in north Indian population.

The Impact of PPARγ Genetic Variants on IBD Susceptibility and IBD Disease Course

PPARγ is a nuclear receptor that regulates numerous pathways including cytokine expression and immune responses and plays an important role in controlling colon inflammation. We aimed at determining the occurring PPARγ SNPs, at predicting the haplotypes, and at determining the frequency outcome in inflammatory bowel disease (IBD) patients in comparison with healthy controls. We determined genetic variants in the coding exons and flanking intronic sequences of the NR1C3 gene in 284 IBD patients and 194 controls and predicted NR1C3 haplotypes via bioinformatic analysis. We investigated whether certain NR1C3 variants are associated with susceptibility to IBD or its disease course. None of the detected 22 NR1C3 variants were associated with IBD. Two variants with allelic frequencies over 1% were included in haplotype/diplotype analyses. None of the NR3C1 haplotypes showed association with IBD development or disease course. We conclude that NR1C3 haplotypes are not related to IBD susceptibility or IBD disease activity.

Effects of the PPARG P12A and C161T gene variants on serum lipids in coronary heart disease patients with and without Type 2 diabetes

We investigated whether PPAR-γ2 gene polymorphisms are associated with serum lipids and the occurrence of coronary heart disease (CHD) prospectively characterised for the presence or absence of Type 2 diabetes in a Turkish population. Our study included 202 patients with CHD (102 with diabetes, 100 without diabetes) and 105 controls. PPARγ genotypes were determined by PCR-RFLP technique. The PPARγ-C161T CC homozygote genotype was associated with significantly increased CHD risk when compared with the T allele carriers (CT+TT) in CHD patients with diabetes (OR:1.951, 95%CI: 1.115-3.415, P = 0.019), whereas PPARγ-P12A polymorphism was not associated with CHD risk (P > 0.05). Serum HDL-C levels were significantly lower in controls with the P12A heterozygote when compared with the P12P homozygote (P = 0.002). In the CHD patients with diabetes, CT heterozygote genotype showed higher serum triglyceride than the CC homozygote genotype (CT:2.42 ± 1.89 vs. CC:1.61 ± 0.21, P = 0.015). Our findings shows the association of these two polymorphisms with serum triglyceride levels, which was increased in the order of P12P-CC < P12P-CT < P12A-CC < P12A-CT in the CHD patients with diabetes. Furthermore, we observed that the increasing effects of the CT genotype on serum triglyceride levels could be modified by PPARγ P12A polymorphism (P12A-CT:2.30 ± 1.75 vs. P12P-CC:1.79 ± 1.14, P = 0.028). We suggested that homozygote CC genotype of the PPARγ C161T polymorphism might be associated with an increased CHD risk especially in patients with diabetes. We observed that the C161T CT heterozygote genotype shows an unfavorable effect on serum lipid profile in CHD patients with diabetes and this effect was weaken with the presence of P12P homozygote genotype.

PPARγ2 C1431T genotype increases metabolic syndrome risk in young men with low cardiorespiratory fitness

The peroxisome proliferator-activated receptor gamma 2 (PPARγ2) genotypes are related to obesity and the metabolic syndrome (MetS). A low level of cardiorespiratory fitness is also a strong determining factor in the development of MetS. This cross-sectional study was performed to investigate the influence of the interaction between the PPARγ2 genotype and cardiorespiratory fitness on the risk of MetS. Healthy Japanese men ( n = 211) and women ( n = 505) participated in this study. All subjects were divided into 8 groups according to sex, fitness level (high and low fitness groups), and age (younger, age < 40 yr; middle-aged/older, age ≥ 40 yr). The PPARγ2 genotypes (Pro12Ala and C1431T) were analyzed by real-time PCR with Taq-Man probes. Two-way ANCOVA with adjustment for age as a covariate indicated that fitness and the CC genotype of C1431T in the PPARγ2 gene interacted to produce a significant effect on MetS risk in younger men and that the risk of MetS in the CC genotype group with low cardiorespiratory fitness was significantly higher than that in the corresponding CT+TT genotypes or in the high fitness groups. There was no significant interaction between fitness and genotype in determining MetS risk in middle-aged/older men or in women in any group. With regard to the Pro12Ala genotype of the PPARγ2 gene, there were no significant differences in fitness or genotype effects nor were there any interactions between measurement variables. We concluded that the CC genotype of C1431T in the PPARγ2 gene together with low cardiorespiratory fitness may increase the risk of MetS in younger men (age < 40 yr), even with adjustment for age.

Pro12Ala polymorphism of the peroxisome proliferator-activated receptor γ2 in patients with fatty liver diseases

AIM: To test the occurrence of the Pro12Ala mutation of the peroxisome proliferator-activated receptor-γ (PPARγ)2-gene in patients with non-alcoholic fatty liver disease (NAFLD) or alcoholic fatty liver disease (AFLD).

METHODS: DNA from a total of 622 specimens including 259 blood samples of healthy blood donors and 363 histologically categorized liver biopsies of patients with NAFLD (n = 263) and AFLD (n = 100) were analyzed by Real-time polymerase chain reaction using allele-specific probes.

RESULTS: In the NAFLD and the AFLD collective, 3% of the patients showed homozygous occurrence of the Ala12 PPARγ2-allele, differing from only 1.5% cases in the healthy population. In NAFLD patients, a high incidence of the Ala12 mutant was not associated with the progression of fatty liver disease. However, we observed a significantly higher risk (odds ratio = 2.50, CI: 1.05-5.90, P = 0.028) in AFLD patients carrying the mutated Ala12 allele to develop inflammatory alterations. The linkage of the malfunctioning Ala12-positive PPARγ2 isoform to an increased risk in patients with AFLD to develop severe steatohepatitis and fibrosis indicates a more prominent anti-inflammatory impact of PPARγ2 in progression of AFLD than of NAFLD.

CONCLUSION: In AFLD patients, the Pro12Ala single nuclear polymorphism should be studied more extensively in order to serve as a novel candidate in biomarker screening for improved prognosis.

Evidences on three relevant obesogenes: MC4R, FTO and PPARγ. Approaches for personalized nutrition

Obesity is a complex disease that results from the interaction between lifestyle (dietary patterns and sedentary habits) and genetic factors. The recognition of a genetic basis for human obesity has driven to identify putative causal genes to understand the pathways that control body mass and fat deposition in humans as well as to provide personalized treatments and prevention strategies to fight against obesity. More than 120 candidate genes have been associated with obesity-related traits. Genome-wide association study has so far identified over 20 novel loci convincingly associated with adiposity. This review is specifically focused on the study of the effects of melanocortin 4 receptor, Peroxisome proliferator-activated receptor γ and fat mass and obesity associated (FTO) gene variants and their interactions with dietary intake, physical activity or drug administration on body weight control. The advances in this field are expected to open new ways in genome-customized diets for obesity prevention and therapy following personalized approaches.

The Ala allele in the PPAR-gamma2 gene is associated with reduced risk of type 2 diabetes mellitus in Caucasians and improved insulin sensitivity in overweight subjects

The purpose of the present study was to identify the association of the Pro12Ala polymorphism in the PPAR-gamma2 gene with diabetes, insulinaemia and insulin resistance. A meta-analysis study was carried out based on studies conducted in the last 10 years, using the databases PubMed, ISI Web of Knowledge, High Wire Press and Scielo, and the reference lists of the obtained articles. We included original studies that showed the relationship between the Pro12Ala polymorphism in the PPAR-gamma2 gene and type 2 diabetes mellitus (T2DM), insulinaemia and insulin resistance. Statistical analyses were conducted using the program RevMAn 5.0. The Mantel-Haenszel test was used to estimate the OR and the 95 % CI of the dichotomous variable, while the standardised effect size was used to estimate the average standardised mean difference and 95 % CI of continuous variables. The studies were subgrouped by ethnicity and overweight status. Forty-one studies were analysed, including a global sample of 30 612 subjects. We found a significant association of the Ala allele with the lowest risk of T2DM in Caucasians (OR 0.80; 95 % CI 0.65, 0.98), lower serum insulin (standardised effect size: - 0.05; 95 % CI - 0.09, - 0.00; P = 0.04), and greater sensitivity to insulin in overweight individuals (homeostasis model assessment of insulin resistance standardised effect size: - 0.07; 95 % CI - 0.13, - 0.01; P = 0.02). Considering that the Pro12Ala polymorphism in the PPAR-gamma2 gene is one of the factors related to insulin sensitivity, the present study demonstrated a significant effect of the Ala allele on lower development of T2DM in Caucasians and greater sensitivity to insulin in overweight subjects.

Three novel SNPs in the coding region of PPARγ gene and their associations with meat quality traits in cattle

The peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear hormone receptor that regulates adipogenesis and many other biological processes. In the present study, we carried out PCR-SSCP and DNA sequencing analyses to examine SNPs in coding region of the PPARγ gene. A total of 660 individuals from five Chinese cattle breeds were genotyped. We identified three SNPs and their associations with meat quality traits were analyzed in 108 Qinchuan cattle. Two missense mutations and one synonymous mutation were found: 200 A>G (genotypes AA, AB and BB) resulting in D7G change, the silent substitution 42895 C>T (genotypes JJ and JI) and 72472 G>T (genotypes CC, DC and DD) producing Q448H change, respectively. The frequencies of PPARγ-A allele were 0.86, 0.83, 0.80, 0.72 and 0.87 for Qinchuan, Nanyang, Jiaxian, Luxi and Xianan populations, respectively. The frequencies of PPARγ-J allele varied from 0.87 to 0.96 in the five populations. In the 72472 G>T locus, the frequencies of PPARγ-C allele were higher than PPARγ-D allele in the five populations, and ranged from 0.58 to 0.82. Least squares analysis revealed that in 42895 C>T locus, there was a significant effect on tenderness in 18-20 months Qinchuan cattle (P<0.01), and in the 72472 G>T locus, animals with the genotype DC had lower mean values than these with genotype CC (P<0.01) for back fat thickness in 18-20 months, and animals with the genotype DD had lower mean values than these with genotypes CC and DC (P<0.01) for water holding capacity in 21-24 months (P<0.01). The SNPs we have identified may contribute to establishing a more efficient selection program for improving of genetic characteristics in indigenous Chinese cattle.

Concordance of two multiple analytical approaches demonstrate that interaction between BMI and ADIPOQ haplotypes is a determinant of LDL cholesterol in a general French population

Genetic and environmental factors are involved in insulin resistance (IR). IR and dyslipidemia associate with increased risk of cardiovascular diseases. Plasma low-density lipoprotein cholesterol (LDL-C) level is a marker of cardiovascular risk. In a Caucasian general population we aimed at determining the multifactorial components of LDL-C levels using 10 genes and 3 phenotypes. In the PPARG, UCP3, ADIPOQ, TNF, LIPC, CARTPT, PCSK9, SCAP, SCARB1 and ENPP1 genes known to be associated with IR or dyslipidemia we genotyped 19 single nucleotide polymorphisms (SNPs) in 846 subjects. When several SNPs were genotyped for a given gene we constructed haplotypes. Including genetic and environmental variables (gender, body mass index (BMI) and adiponectin level) we used (1) the multifactor dimensionality reduction method to explain clusters of high and low LDL-C, and (2) the restricted partition method to explain LDL-C levels. Both methods showed that BMI and haplotypes at the ADIPOQ adiponectin encoding gene but not adiponectin level itself, were discriminant regarding to LDL-C. Subjects bearing an at-risk combination of BMI and ADIPOQ genotypes were prone to have a higher LDL-C (OR=3.13, 95% CI=2.20-4.46, P<0.0001). Our results suggest that in interaction with BMI, ADIPOQ haplotypes capture genetic variation(s) from neighboring gene(s) that would modulate LDL-C level.

Breast-feeding modulates the influence of the peroxisome proliferator-activated receptor-gamma (PPARG2) Pro12Ala polymorphism on adiposity in adolescents: The Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) cross-sectional study

OBJECTIVE

The peroxisome proliferator-activated receptor-gamma2 (PPARG2) Pro12Ala polymorphism has been associated with a higher BMI and a lower risk of type 2 diabetes in adulthood. The association between adiposity and PPARG variants can be influenced by environmental factors such as early growth, dietary fat, and (as recently shown) breast-feeding. The objectives of this study were to assess 1) the influence of the PPARG2 Pro12Ala polymorphism on adiposity markers in adolescents and 2) a possible modulating effect of breast-feeding on these associations.

RESEARCH DESIGN AND METHODS

Data on breast-feeding duration, BMI, and genotypes for the Pro12Ala polymorphism were available for 945 adolescents (mean age 14.7 years). The breast-feeding duration was obtained from parental records. We measured weight, height, waist circumference, and six skinfold thicknesses.

RESULTS

No significant associations between the Pro12Ala polymorphism and any of the above-mentioned anthropometric parameters were found. There were significant interactions between the PPARG2 Pro12Ala polymorphism and breast-feeding with regard to adiposity measurements (all adjusted P < 0.05). Indeed, in children who had not been breast-fed, Ala12 allele carriers had higher adiposity parameters (e.g., Delta BMI +1.88 kg/m(2), adjusted for age, sex, and center, P = 0.007) than Pro12Pro adolescents. In contrast, in breast-fed subjects, there was no significant difference between Ala12 allele carriers and Pro12Pro children in terms of adiposity measurements, whatever the duration of breast-feeding.

CONCLUSIONS

Breast-feeding appears to counter the deleterious effect of the PPARG2 Pro12Ala polymorphism on anthropometric parameters in adolescents.

Associations between common genetic polymorphisms in angiopoietin-like proteins 3 and 4 and lipid metabolism and adiposity in European adolescents and adults

CONTEXT

Plasma-borne angiopoietin-like proteins (ANGPTL) act as endocrine factors on their target tissues. Because ANGPTL3 and ANGPTL4 play important roles in lipid metabolism and the regulation of adiposity in mice, we hypothesized that genetic variability at the ANGPTL3 and ANGPTL4 genes loci might influence lipid metabolism and fat deposition in humans.

OBJECTIVE

The aim of the study was to examine the association between ANGPTL3 and ANGPTL4 genetic polymorphisms and metabolic phenotypes in adolescent and adult samples.

DESIGN AND PARTICIPANTS

Two independent population-based studies, one composed of 1144 adolescents (mean age, 14.8 +/- 1.4 yr) from nine European countries (the HELENA study) and the other composed of 1155 adults (age range, 35-65 yr) from Northern France (the MONICA Lille study), were genotyped for one ANGPTL3 polymorphism and four ANGPTL4 polymorphisms.

RESULTS

The ANGPTL3 rs11207997 polymorphism (minor allele frequency, 0.32) was associated with lower plasma HDL-cholesterol and apolipoprotein A-I levels in both adolescents (P = 0.0004, P = 0.00006, respectively) and adults (P = 0.03, P = 0.02, respectively). The ANGPTL4 rs4076317 polymorphism (minor allele frequency, 0.29) was associated with a higher percentage of body fat (P = 0.02) in adolescents and a higher waist-to-hip ratio (in interaction with the peroxisome proliferator-activated receptor gamma Pro12Ala polymorphism) in adults (P = 0.0004).

CONCLUSION

The present study underlines the role of ANGPTL3 in HDL-cholesterol metabolism as early as in adolescence. Our data also suggest possible associations between ANGPTL4 polymorphisms and body fat, but these findings require replication.

Pro12Ala polymorphism of the peroxisome proliferatoractivated receptor-gamma gene is associated with metabolic syndrome and surrogate measures of insulin resistance in healthy men: interaction with smoking status

BACKGROUND

The Pro12Ala polymorphism (rs1801282), a nonsynonymous substitution of peroxisome proliferator-activated receptor-gamma (PPARG), has been robustly associated with type 2 diabetes. However, its role in metabolic syndrome (MetS) remains poorly understood. The associations among rs1801282, MetS and surrogate measures of insulin resistance (IR) were investigated in the present study.

METHODS AND RESULTS

A cross-sectional population-based survey of 572 unrelated healthy male Argentinian blood donors with normal findings on medical examination and not taking any medication was conducted. MetS was assessed using the National Cholesterol Education Program/Adult Treatment Panel III (NCEP/ATP III) criteria, and the HOMA-IR, and QUICKI were calculated. Genotyping of rs1801282 was performed using RFLP-PCR. The prevalence of MetS was 26.2%. The Pro/Ala genotype (and the Ala12 allele) was associated with a high risk for MetS (odds ratio (OR) 1.67 [95% confidence interval (CI) 1.03-2.72], P=0.0394). This was highlighted among nonsmokers (OR 2.20 [95%CI 1.25-3.88], P=0.0059). ANCOVA confirmed an interaction between smoking status and this association (P=0.031). Ala12 carriers had a higher waist circumference than noncarriers (P=0.0065). Among nonsmokers, surrogates of IR, such as HOMA-IR, were significantly higher in Ala12 carriers than in noncarriers (P<0.05).

CONCLUSIONS

Healthy men, in particular nonsmokers, carrying the Ala12 allele of PPARG rs1801282 polymorphism, have a high risk for MetS and IR.

Fat poetry: a kingdom for PPAR gamma

Adipose tissue is not an inert cell mass contributing only to the storage of fat, but a sophisticated ensemble of cellular components with highly specialized and complex functions. In addition to managing the most important energy reserve of the body, it secretes a multitude of soluble proteins called adipokines, which have beneficial or, alternatively, deleterious effects on the homeostasis of the whole body. The expression of these adipokines is an integrated response to various signals received from many organs, which depends heavily on the integrity and physiological status of the adipose tissue. One of the main regulators of gene expression in fat is the transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma), which is a fatty acid- and eicosanoid-dependent nuclear receptor that plays key roles in the development and maintenance of the adipose tissue. Furthermore, synthetic PPARgamma agonists are therapeutic agents used in the treatment of type 2 diabetes.This review discusses recent knowledge on the link between fat physiology and metabolic diseases, and the roles of PPARgamma in this interplay via the regulation of lipid and glucose metabolism. Finally, we assess the putative benefits of targeting this nuclear receptor with still-to-be-identified highly selective PPARgamma modulators.

Birth weight and blood lipid levels in Spanish adolescents: influence of selected APOE, APOC3 and PPARgamma2 gene polymorphisms. The AVENA Study

Background

There is increasing evidence indicating that genes involved in certain metabolic processes of cardiovascular diseases may be of particular influence in people with low body weight at birth. We examined whether the apolipoprotein (APO) E, APOC3 and the peroxisome proliferator-activated receptor-γ-2 (PPARγ2) polymorphisms influence the association between low birth weight and blood lipid levels in healthy adolescents aged 13–18.5 years.

Methods

A cross-sectional study of 502 Spanish adolescents born at term was conducted. Total (TC) and high density lipoprotein cholesterol (HDLc), triglycerides (TG), apolipoprotein (apo) A and B, and lipoprotein(a) [Lp(a)] were measured. Low density lipoprotein cholesterol (LDLc), TC-HDLc, TC/HDLc and apoB/apoA were calculated.

Results

Low birth weight was associated with higher levels of TC, LDLc, apoB, Lp(a), TC-HDLc, TC/HDLc and apoB/apoA in males with the APOE ε3ε4 genotype, whereas in females, it was associated with lower HDLc and higher TG levels. In males with the APOC3 S1/S2 genotype, low birth weight was associated with lower apoA and higher Lp(a), yet this association was not observed in females. There were no associations between low birth weight and blood lipids in any of the PPARγ2 genotypes.

Conclusion

The results indicate that low birth weight has a deleterious influence on lipid profile particularly in adolescents with the APOE ε3/ε4 genotype. These findings suggest that intrauterine environment interact with the genetic background affecting the lipid profile in later life.

Association of peroxisome proliferator-activated receptorgamma gene Pro12Ala and C161T polymorphisms with metabolic syndrome

BACKGROUND Peroxisome proliferator-activated receptor gamma (PPARgamma) is involved mainly in adipocyte differentiation and has been suggested to play an important role in the pathogenesis of insulin resistance (IR) and atherosclerosis. The frequencies of 2 common polymorphisms of the PPARgamma gene, Pro12Ala single nucleotide polymorphism (SNP) in exon B and C161T SNP in exon 6, were investigated in 792 subjects and the correlations between the different genotypes, IR and metabolic syndrome (MS) were analyzed.

METHODS AND RESULTS

Anthropometric measurements, fasting glucose, insulin and lipid profiles were measured in 792 people of the Han population in Beijing, China. Homeostatic model assessments and quantitative insulin sensitivity check indices were calculated. MS was diagnosed according to the IDF guidelines (2005) for a Chinese population. Polymerase chain reaction - restriction fragment length polymorphism were performed for DNA genotyping. For the C161T polymorphism, allele frequencies were 0.804 for the C allele and 0.196 for the T allele. For Pro12Ala, allele frequencies were 0.947 for proline and 0.053 for alanine. There was no Ala12Ala homozygote in the population. No differences were seen in the mean values of age, body mass index (BMI), blood pressure or fasting blood glucose level among different genotypes when analyzed as a whole. Subjects with an A or T allele had lower fasting insulin levels, HOMA-IR levels, and a lower level QUICKI trend. Further analysis by age was conducted, and A or T allele carriers in the <60 year group showed a trend of lower triglyceride and a higher high-density lipoprotein-cholesterol level, but this was not statistically significant. When subjects were divided into 4 groups according to the combination of genetic alleles of the 2 polymorphisms, the subjects with Pro12Ala and a T allele simultaneously showed a significantly higher BMI than those without the Ala allele. The presence of a T allele in the C161T polymorphism and Pro12Ala polymorphism seems to affect body weight, which is similar to the results found in previous studies.

CONCLUSIONS

Both polymorphisms showed a significant association with IR, but failed to show an association with MS components. Those with an A allele of Pro12Ala and a T allele of the C161T polymorphism showed a higher BMI, which requires further investigation.

[Peroxisome proliferator-activated receptor gamma (PPARgamma): molecular study in glucose homeostasis, lipid metabolism and therapeutic approach]

The peroxisome proliferators-activated receptors (PPARs) are transcription factors belonging to the family of nuclear receptors that regulate glucose homeostasis, lipid metabolism and inflammation. Three proteins, encoded by distinct genes, have been identified: PPARalpha, PPARbeta and PPARgamma, which control gene expression by binding to specific response elements (PPREs) in the promoters. Recent studies suggest that activation of PPARgamma might decrease atherosclerosis progression and increase the insulin sensitivity, might be a potential therapeutic target for the treatment of a diverse array of disorders, including type 2 diabetes and dyslipidaemia. This review highlights recent studies, which have advanced our understanding of the pivotal role that this receptor plays in metabolism, with particular reference to the molecular mechanisms and therapeutic efficacy.

Peroxisome proliferator-activated receptor gamma-2 P12A polymorphism and risk of acute myocardial infarction, coronary heart disease and ischemic stroke: a case-cohort study and meta-analyses

Background

The alanine allele of P12A polymorphism in PPARG gene in a few studies has been associated with a reduced or increased risk of acute myocardial infarction (AMI). Yet, the risk relation has not been confi rmed, and data on ischemic stroke (IS) is scarce. We therefore investigated the role of this polymorphism on occurrence of AMI, coronary heart disease (CHD) and IS.

Methods and fi ndings

We performed a case-cohort study in 15,236 initially healthy Dutch women and applied a Cox proportional hazards model to study the relation of the P12A polymorphism and AMI (n = 71), CHD (n = 211), and IS (n = 49) under different inheritance models. In addition, meta-analyses of published studies were performed. Under the dominant inheritance model, carriers of the alanine allele compared with those with the more common genotype were not at increased or decreased risk of CHD (hazard ratio [HR] = 0.82; 95% confi dence interval [CI], 0.58 to 1.17) and of IS (HR = 1.03; 95% CI, 0.14 to 7.74). In addition no relations were found under the recessive and additive models. Our meta-analyses corroborated these fi ndings by showing no signifi cant association. For AMI we found a borderline signifi cant association under dominant (HR = 0.49; 95% CI, 0.26 to 0.94), and additive (HR = 0.51; 95% CI, 0.26 to 1.00) models which could be due to chance, because of small cases in this subgroup. The meta-analysis did not show any association between the polymorphism and risk of AMI under the different genetic models.

Conclusions

Our study in healthy Dutch women in combination with the meta-analyses of previous reports does not provide support for a role of P12A polymorphism in PPARG gene in MI and CHD risk. Also our study shows that the polymorphism has no association with IS risk.

Interaction between PPARgamma2 variants and gender on the modulation of body weight

Conflicting results have been reported regarding the effect of the peroxisome proliferator-activated receptor-gamma-2 (PPARgamma2) Pro12Ala polymorphism, (singly or in combination with the silent C1431T polymorphism) on BMI. Gender-based dimorphism has been evidenced for genes that affect BMI, but few and conflicting data are available regarding PPARgamma2. We sought to investigate whether the Pro12Ala interacts with gender in modulating BMI in 566 nondiabetic unrelated white subjects (men:women = 211:355, age 36.59 +/- 11.85; BMI 25.36 +/- 4.53). In the whole study population, BMI, fasting glucose and insulin levels, and lipid profile were similar in Ala12 carriers (i.e., XA) and Pro/Pro homozygous subjects. Among the men, but not among the women, X/Ala individuals showed higher BMI (25.9 +/- 3.6 vs. 28.2 +/- 4.9, P = 0.006) and risk of obesity (odds ratio = 2.85, 95% confidence interval = 1.07-7.62). A significant gene-gender interaction in modulating BMI was observed (P = 0.039). Among the men, but not among the women, those carrying Ala-T haplotype (i.e., containing both Ala12 and T1431 variants) showed the highest BMI (haplo-score = 3.72, P = 0.0014). Our data indicate that in whites from Italy the PPARgamma2 Pro12Ala polymorphism interacts with gender in modulating BMI, thereby replicating some, but not all, earlier data obtained in different populations. Whether the PPARgamma2-gender interaction is a general phenomenon across different populations, is still an open question, the answer to which requires additional, specifically designed, studies.

Association of pro12Ala polymorphism in the peroxisome proliferative-activated receptor gamma2 gene with obesity and hypertension in Korean women

This study examined whether the Pro12Ala polymorphism of the PPARgamma2 gene is associated with obesity, hypertension and cardiovascular risk profiles in Korean adult women. We studied 129 Korean women (aged 42.71 +/- 8.56 y) who were divided into 2 groups as a Pro12Pro homozygous group and a Pro12Ala heterozygous or Ala12Ala homozygous group based upon PPARy2 genotype. Anthropometric parameters, blood pressure, abdominal fat area and blood lipid profiles were compared between the 2 groups, and the association of Ala allele frequency in PPARgamma2 gene with obesity or hypertension was evaluated. Most anthropometric parameters and blood lipid profiles did not differ significantly between the genotypes. However, all variables of skinfold thickness, body circumference and abdominal fat area of Pro12Ala heterozygous were consistently higher compared to the Pro12Pro homozygous subjects without a significance differences. The hypertensive group had significantly higher (p = 0.004) Ala12 allele frequency than the normotensive group whereas allele frequencies did not differ significantly between the obese group and non-obese group. Ala allele carriers had a significantly higher risk of hypertension than non-carriers in logistic regression analysis. There was no evidence that the Ala allele can be regarded as an independent risk factor for obesity. In conclusion, all variables related to obesity showed a consistently higher trend in Pro12Ala heterozygous subjects compared to Pro12Pro homozygous subjects. Pro12Ala heterozygous subjects showed an increasing trend of elevated blood pressure compared to Pro12Pro homozygous subjects. Ala12 variant as well as BMI and TG were regarded as independent risk factors for hypertension in our subjects.

An analysis of peroxisome proliferator-activated receptor gamma (PPAR-gamma 2) Pro12Ala polymorphism distribution and prevalence of type 2 diabetes mellitus (T2DM) in world populations in relation to dietary habits

BACKGROUND AND AIM

The human peroxisome proliferator-activated receptor gamma (PPAR-gamma) is involved in lipid storage, glucose homeostasis and adipocyte differentiation. The Ala allele of the Pro12Ala polymorphism has been associated with a protective effect against T2DM. Ala allele frequencies are known for many populations, but data are absent for other interesting human groups.

METHODS AND RESULTS

We examined samples from Ethiopia, Benin, Ecuador and Italy. In addition, we performed an analysis of the Pro12Ala polymorphism distribution in world populations, also in relation to T2DM prevalence and the diet lipid content. In the European populations, the Ala allele frequencies are distributed according to a latitudinal trend, with the highest in the northern and central European populations and the lowest in the Mediterranean populations. Considering the world populations, a significant inverse relationship between Ala frequency and T2DM prevalence was observed mainly in populations where energy from lipids exceeded 30% of the total energy intake.

CONCLUSION

Northern Europe's cold climate has been hypothesised to have played a role in contributing to the present pattern. Moreover our analysis appears to confirm, at a population level, the protective effect of Ala allele against T2DM, already observed in case-control studies, but only in populations with a diet rich in lipids.

Association of Pro12Ala polymorphism in the peroxisome proliferator-activated receptor gamma2 gene with small dense low-density lipoprotein in the general population

The Pro12Ala polymorphism of the peroxisome proliferator-activated receptor gamma2 (PPARgamma2) gene has been reported to predict a lower risk for developing type 2 diabetes mellitus. However, its effect on the lipid profile has been disputable. Among low-density lipoproteins, small dense low-density lipoprotein (sdLDL) particles have been linked to a greater risk for coronary artery disease. The purpose of this study was to investigate the genetic effect of the Pro12Ala polymorphism in the PPARgamma2 gene on the presence of sdLDL in the general Japanese population. In 379 subjects (aged 54 +/- 13 years), body mass index, percentage of body fat, blood pressure, and biochemical profiles were measured. Pro12Ala polymorphism was genotyped by polymerase chain reaction-restriction fragment length polymorphism. The area of sdLDL subfractions (sdLDL4-7) was analyzed by high-resolution polyacrylamide gel electrophoresis. The frequency of the Ala12 allele in PPARgamma2 was 0.04. There was no difference in total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol levels between genotypes. However, subjects with the X/Ala genotype (Pro/Ala + Ala/Ala) had significantly higher serum triglyceride levels (P = .001) and a larger area of sdLDL4-7 (P = .002) than those with the Pro/Pro genotype. Multiple regression analysis revealed that the Ala12 allele was a significant variable contributing to the variance in the increased area of sdLDL4-7 (P = .040). In conclusion, the Pro12Ala polymorphism in the PPARgamma2 gene was positively associated with an enlarged area of sdLDL4-7. This polymorphism may play a role in the genetic predisposition to increases in sdLDL4-7.