Peroxisome proliferator-activated receptor-gamma2 P12A polymorphism and risk of coronary heart disease in US men and women

G Allele of the rs1801282 Polymorphism in PPARγ Gene Confers an Increased Risk of Obesity and Hypercholesterolemia, While T Allele of the rs3856806 Polymorphism Displays a Protective Role Against Dyslipidemia: A Systematic Review and Meta-Analysis

BACKGROUND

The relationships between the rs1801282 and rs3856806 polymorphisms in nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) gene and obesity indexes as well as serum lipid levels have been extensively investigated in various studies, but the results were inconsistent and even contradictory.

METHODS

PubMed, Google Scholar, Embase, Cochrane Library, Web of Science, Wanfang, CNKI and VIP databases were searched for eligible studies. The random-effTPDEects model was used, and standardized mean difference (SMD) with 95% confidence interval (CI) was calculated to estimate the differences in obesity indexes and serum lipid levels between the subjects with different genotypes in a dominant model. Heterogeneity among studies was assessed by Cochran's x²-based Q-statistic test. Publication bias was identified by using Begg's test.

RESULTS

One hundred and twenty studies (70,317 subjects) and 33 studies (18,353 subjects) were identified in the analyses for the rs1801282 and rs3856806 polymorphisms, respectively. The G allele carriers of the rs1801282 polymorphism had higher levels of body mass index (SMD = 0.08 kg/m², 95% CI = 0.04 to 0.12 kg/m², p < 0.001), waist circumference (SMD = 0.12 cm, 95% CI = 0.06 to 0.18 cm, p < 0.001) and total cholesterol (SMD = 0.07 mmol/L, 95% CI = 0.02 to 0.11 mmol/L, p < 0.01) than the CC homozygotes. The T allele carriers of the rs3856806 polymorphism had lower levels of low-density lipoprotein cholesterol (SMD = -0.09 mmol/L, 95% CI = -0.15 to -0.03 mmol/L, p < 0.01) and higher levels of high-density lipoprotein cholesterol (SMD = 0.06 mmol/L, 95% CI = 0.02 to 0.10 mmol/L, p < 0.01) than the CC homozygotes.

CONCLUSIONS

The meta-analysis suggests that the G allele of the rs1801282 polymorphism confers an increased risk of obesity and hypercholesterolemia, while the T allele of the rs3856806 polymorphism displays a protective role against dyslipidemia, which can partly explain the associations between these polymorphisms and cardiovascular disease.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier [CRD42022319347].

PPARA, PPARD and PPARG gene polymorphisms in patients with unstable angina

BACKGROUND

Peroxisome proliferator-activated receptors (PPARs) include the nuclear receptor superfamily of ligand-activated transcription factors involved in several metabolic processes, including carbohydrate and lipid metabolism.

MATERIAL AND METHODS

In this study we examined PPARA: rs4253778, rs1800206, PPARD: rs2267668, rs2016520, rs1053049, PPARG rs1801282 and PPARGC1A rs8192678 polymorphisms in patients with unstable angina. This study included 246 patients with unstable angina confirmed by coronary angiography (defined by >70% stenosis in at least one major coronary artery) and 189 healthy controls.

RESULTS

We observed statistically significant difference in distribution of PPARG rs1801282 genotypes and alleles between patients and control group. Among patients there was the increased frequency of CG and GG genotypes and G alleles. The association between PPARG rs1801282 G allele and unstable angina was confirmed in multivariate regression analysis. There were no statistically significant differences in the distributions of other studied polymorphisms between patients with unstable angina and the control group.

CONCLUSIONS

The results of our study suggest the association between PPARG rs1801282 G allele and unstable angina in Polish population.

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.

Association between peroxisome proliferator-activated receptor-alpha, delta, and gamma polymorphisms and risk of coronary heart disease: A case-control study and meta-analysis

OBJECTIVES

Risk of coronary heart disease (CHD) has been suggested to be associated with polymorphisms of peroxisome proliferator-activated receptors (PPARs), while the results were controversial. We aimed to systematically assess the association between PPAR polymorphisms and CHD risk.

METHODS

A case-control study with 446 subjects was conducted to evaluate the association between CHD risk and C161T polymorphism, which was of our special interest as this polymorphism showed different effects on risks of CHD and acute coronary syndrome (ACS). Meta-analyses were conducted to assess all PPAR polymorphisms. Either a fixed- or a random-effects model was adopted to estimate overall odds ratios (ORs).

RESULTS

In the case-control study, T allele carriers of C161T polymorphism were not significantly associated with CHD risk (Odds ratio (OR) = 0.74, 95% confidence interval (CI) 0.47-1.15, P = 0.19), while T allele carriers showed higher risk of ACS (OR = 1.63, 95% CI 1.00-2.65, P = 0.048). The meta-analysis indicated that compared with CC homozygous, T allele carriers had lower CHD risk (OR = 0.69, 95% CI 0.59-0.82, P < 0.001) but higher ACS risk (OR = 1.43, 95% CI 1.09-1.87, P = 0.010). Three other polymorphisms were also found to be significantly associated with CHD risk under dominant model: PPAR-alpha intron 7G/C polymorphism (CC+GC vs GG, OR 1.42, 95% CI 1.13-1.78, P = 0.003), L162V polymorphism (VV+LV vs LL, OR 0.74, 95% CI 0.56-0.97, P = 0.031), and PPAR-delta +294T/C polymorphism (CC+TC vs TT, OR 1.51, 95% CI 1.12-2.05, P = 0.007).

CONCLUSIONS

The results suggested that PPAR-alpha intron 7G/C and L162V, PPAR-delta +294T/C and PPAR-gamma C161T polymorphisms could affect CHD susceptibility, and C161T polymorphism might have different effects on CHD and ACS.

Genetic predictors of obesity development

The most common reasons that cause obesity are eating disorders (overeating), genetic predisposition, sedentary lifestyle (lack of exercise), disorders of the endocrine system, and environmental factors. There is evidence of an obvious relationship of high consumption of sugary drinks and weight gain. Since 1990, there has been considerable growth in the number of obese people in the first place associated with the promotion of soft drinks. According to a study in Finnish diabetes prevention average physical activity and change of diet (1200-1800 kcal) of total fat intake with less than 30% saturated fat, including less than 10%, leading to long-term loss of excess weight (within 4 years). Many studies have demonstrated the impossibility of a single template approach to the determination of optimal diets for patients with overweight and obesity which has been shown in various studies on gene polymorphisms are associated with obesity, and their interaction. This article provides an overview of current data on the genetics of obesity covering the main provisions of the study of candidate genes, such as PPARG, FABP2, ADRB 2, ADRB3. The role nutrigenetics in the creation of individual programs of weight control and weight loss. But the question of the direct role of genetic factors in the development of obesity remains controversial, since one can not ignore the impact of environmental factors, such as lifestyle, diet, physical activity, stress, and harmful habits. To understand the mechanism of the relationship between genetic factors, environmental factors, and obesity, one needs to carry out research not only on the population level, but also in certain groups of people (ethnic, racial, age).

Heat shock factor-1 knockout enhances cholesterol 7α-hydroxylase (CYP7A1) and multidrug transporter (MDR1) gene expressions to attenuate atherosclerosis

AIMS

Stress response, in terms of activation of stress factors, is known to cause obesity and coronary heart disease such as atherosclerosis in human. However, the underlying mechanism(s) of these pathways are not known. Here, we investigated the effect of heat shock factor-1 (HSF-1) on atherosclerosis.

METHODS AND RESULTS

HSF-1 and low-density lipoprotein receptor (LDLr) double knockout (HSF-1(-/-)/LDLr(-/-)) and LDLr knockout (LDLr(-/-)) mice were fed with atherogenic western diet (WD) for 12 weeks. WD-induced weight gain and atherosclerotic lesion in aortic arch and carotid regions were reduced in HSF-1(-/-)/LDLr(-/-) mice, compared with LDLr(-/-) mice. Also, repression of PPAR-γ2 and AMPKα expression in adipose tissue, low hepatic steatosis, and lessened plasma adiponectins and lipoproteins were observed. In HSF-1(-/-)/LDLr(-/-) liver, higher cholesterol 7α-hydroxylase (CYP7A1) and multidrug transporter [MDR1/P-glycoprotein (P-gp)] gene expressions were observed, consistent with higher bile acid transport and larger hepatic bile ducts. Luciferase reporter gene assays with wild-type CYP7A1 and MDR1 promoters showed lesser luminescence than with mutant promoters (HSF-1 binding site deleted), indicating that HSF-1 binding is repressive of CYP7A1 and MDR1 gene expressions.

CONCLUSION

HSF-1 ablation not only eliminates heat shock response, but it also transcriptionally up-regulates CYP7A1 and MDR1/P-gp axis in WD-diet fed HSF-1(-/-)/LDLr(-/-) mice to reduce atherosclerosis.

Association between Peroxisome Proliferator-activated Receptor Gamma Gene Polymorphisms and Atherosclerotic Diseases: A Meta-analysis of Case-control Studies

AIM

The aim of this study was to perform a meta-analysis to investigate the association between PPARγ rs1801282/rs3856806 polymorphisms and atherosclerotic diseases.

METHODS

The meta-analysis was performed by searching the PubMed, Embase and Web of Science databases from the first available year to September 10, 2013. Additionally, reference lists from the identified articles, reviews and abstracts presented at the meetings of related scientific societies were also checked. All case-control studies investigating the association between PPARγ rs1801282/rs3856806 polymorphisms and the risk of atherosclerotic disease were included. The association was assessed according to the odds ratio (OR) with a 95% confidence interval (CI). Publication bias was analyzed using Begg's funnel plot and Egger's regression test.

RESULTS

A total of 29 studies reporting PPARγ rs1801282/rs3856806 polymorphism were included in the final meta-analysis. Neither the rs1801282 (Pro12Ala) nor rs3856806 (C161T) polymorphisms showed any significant associations with susceptibility to atherosclerotic diseases. In the meta-analysis performed to assess the association between the rs3856806 gene polymorphism and atherosclerotic disease based on ethnicity and the type of disease, significant associations were found in the Caucasian subgroup, Asian, CAD and MI subgroups.

CONCLUSIONS

The present data suggest that there is no statistical evidence of a significant association between the PPARγ gene rs1801282/rs3856806 polymorphism and the risk of atherosclerotic disease. In contrast, the rs3856806 polymorphism was associated with an increased risk in the Caucasian and MI subgroups, whereas decreased risks were noted in the Asian and CAD subgroups. Due to significant between-study heterogeneity, further studies with a larger sample size involving homogeneous AS patients and well-matched controls are required in the future.

Association of the variants in the PPARG gene and serum lipid levels: a meta-analysis of 74 studies

Considerable studies have been carried out to investigate the relationship between the polymorphisms of PPARG (Pro12Ala, C161T and C1431T) and serum lipid levels, but the results were inconclusive. Hence, we conducted a meta-analysis to clarify the association. MEDLINE, EMBASE and the Cochrane Library databases were searched systematically. The subgroup analysis was performed based on ethnicity. Seventy-four studies with 54,953 subjects were included in this meta-analysis. In Pro12Ala, the group with the ‘PP’ (C/C genotype) genotype group had lower levels of total cholesterol (TC) (mean difference, MD: −0.02, P < 0.00001; I² = 28%), low-density lipoprotein cholesterol (LDL-C) (MD: −0.02, P < 0.00001; I² = 30%) and higher levels of triglyceride (TG) (MD: 0.06, P < 0.00001; I² = 30%) than the combined ‘PA+AA’ (PA = C/G genotype, AA = G/G genotype) genotype group in Asian population, and the group with the ‘PP’ genotype had higher levels of TG (MD: 0.07, P < 0.02; I² = 67%) than the combined ‘PA+AA’ genotype group in non-Asian population. No statistically significant differences in the levels of TC, TG, high-density lipoprotein cholesterol, LDL-C were detected between different genotypes in C161T(Asian or non-Asian) and C1431T(Asian) polymorphisms. This meta-analysis was a renewed and confirmed study to assess the association between PPARG polymorphisms and serum lipid levels in Asian and non-Asian populations. There is a prominent association between Pro12Ala polymorphism and the levels of TC, LDL-C and TG in Asian population. No statistically significant differences in serum lipid levels were detected between different genotypes in C161T and C1431T polymorphisms.

The association between the Pro12Ala variant in the PPARγ2 gene and type 2 diabetes mellitus and obesity in a Chinese population

Background

Conflicting results have been reported on the association of the Pro12Ala polymorphism of the PPARγ2 gene with the risk of type 2 diabetes or obesity.

Methods and Findings

A total of 3146 subjects with 1145 cases of type 2 diabetes and 2001 healthy controls were included in the study. Genomic DNA was obtained from blood samples and the screening for the gene polymorphisms was done using an allelic discrimination assay-by-design TaqMan method. Overall, the Ala allele frequency was 5.6% in control subjects and 3.9% in diabetes subjects (P = 0.023). We found a statistically significant association of carriers of the Ala allele with greater homoeostasis model assessment of beta cell function index in all subjects (P = 0.046). After controlling for confounders, carriers of the Ala allele had a decreased risk of diabetes compared with noncarriers [odds ratio (OR) 0.64, 95% confidence interval (CI) 0.49–0.83; P = 0.001]. A beneficial effect of the Ala allele was also observed for obesity (OR 0.64, 95% CI 0.42–0.96; P = 0.030).

Conclusion

Our results suggested that the presence of the Ala allele may contribute to improved insulin secretory capacity and may confer protection from type 2 diabetes and obesity in the Chinese population.

The Pro12Ala polymorphism in the peroxisome proliferator-activated receptor gamma-2 gene (PPARγ2) is associated with increased risk of coronary artery disease: a meta-analysis

Background

Contradictory results have been reported regarding the association between Pro12Ala polymorphism of PPARγ2 and coronary artery disease (CAD). We sought to estimate the inconsistent results by performing a comprehensive meta-analysis.

Methods

Studies in English or Chinese publications were identified by screening MEDLINE, Embase, CNKI, Wanfang and CBM. 22 studies including 8948 cases and 14427 controls were selected. A random-effects model was applied to combine the divergent outcomes of the individual studies, while addressing between-study heterogeneity and publication bias.

Results

The Pro12Ala polymorphism of control population followed Hardy-Weinberg equilibrium for all studies (P>0.05). Overall, a marginal increased risk of CAD under the recessive genetic model (AlaAla vs ProAla+ProPro: P = 0.04, OR = 1.31, 95%CI 1.01–1.69, P_{heterogeneity} = 0.67, I² = 0%) and the homozygote comparison (AlaAla vs ProPro: P = 0.04,OR = 1.30, 95%CI 1.01–1.68, P_{heterogeneity} = 0.68, I² = 0%) was observed. In the subgroup analysis by ethnicity, carriers of AlaAla homozygotes had a significant increased risk for CAD among Caucasians (AlaAla vs ProAla+ProPro: P = 0.01, OR = 1.45, 95%CI 1.08–1.96, P_{heterogeneity} = 0.48, I² = 0%; AlaAla vs ProPro: P = 0.02,OR = 1.44, 95%CI 1.07–1.93, P_{heterogeneity} = 0.46, I² = 0%). After dividing into population source, the CAD risk magnitude of hospital-based studies was distinctly strengthened under the recessive model (P = 0.03,OR = 1.85,95%CI 1.07–3.19, P_{heterogeneity} = 0.87,I² = 0%) and the homozygote comparison (P = 0.03,OR = 1.83, 95%CI 1.06–3.16, P_{heterogeneity} = 0.88, I² = 0%). There was no observable publication bias as reflected by funnel plot and Egger’s linear regression test (t = -0.12, P = 0.91).

Conclusion:

Our results demonstrated that the PPARγ2 Pro12Ala polymorphism might be risk-conferring locus for the progression of CAD among Caucasians, but not among Asians.

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 meta-analysis of the association of PPARG P12A, C161T polymorphism and coronary heart disease

OBJECTIVE

Two common variations of peroxisome proliferator-activated receptor γ (PPARG), P12A (Pro12Ala, rs1801282), and C161T (His447His, rs3856806), are thought to have an effect on susceptibility to coronary heart disease (CHD), but the results are inconsistent. Therefore, a meta-analysis of published studies was performed.

METHODS

The electronic databases, PubMed, Embase, Web of Science, and CNKI (China National Knowledge Infrastructure) were searched for studies to include in the present meta-analysis (last search was updated on 30 Aug. 2011). Twenty studies testing the association between PPARG gene polymorphisms and CHD were examined: 12 studies of P12A; 8 studies of C161T. Overall and ethnicity-specific summary odds ratios and corresponding 95 % confidence intervals for CHD associated with these polymorphisms were estimated using fixed- and random-effects models. Heterogeneity and publication bias were evaluated. A total of 20 studies including 5,795 cases and 9,069 controls were included in this meta-analysis.

RESULTS

No significant associations were found in carriers of the rare Ala allele of the P12A polymorphism versus the common Pro/Pro genotype among the studies with both of the fixed-effect and random-effect model. In the subgroup analyses by ethnicity, source of control and type of study, no significant risks were found. For PPARG C161T, carriers of the T variant of C161T polymorphism were associated with an increased risk of CHD (OR = 1.182, 95 % CI: 1.023-1.341, P(heterogeneity) = 0.002), and in the stratified analysis by ethnicity and source of controls, the contrast of CT + TT vs. CC all produced significant association in Asian and hospital-based controls (OR = 1.276, 95 % CI: 1.084-1.468, P(heterogeneity) = 0.055; OR = 1.164, 95 % CI: 1.001-1.326, P(heterogeneity) = 0.002),when the fixed-effect model was used. But they were all insignificant with the random-effect model.

CONCLUSION

This meta-analysis suggests that the PPARG C161T polymorphism marginally contributes to increased susceptibility to CHD and marginally increased association between PPARG H477H polymorphism and CHD also appeared in Asian and hospital-based controls. But PPARG P12A polymorphism is not associated with CHD risk.

Peroxisome proliferator-activated receptor-γ and the endothelium: implications in cardiovascular disease

Peroxisome proliferator-activated receptors-γ (PPARγs) are ligand-activated transcription factors that play a crucial regulatory role in the transcription of a large number of genes involved in lipid metabolism and inflammation. In addition to physiological ligands, synthetic ligands (the thiazoledinediones) have been developed. In spite of the much publicized adverse cardiovascular effects of one such thiazoledinedione (rosiglitazone), PPARγ activation may have beneficial cardiovascular effects. In this article we review the effects of PPARγ activation on the endothelium with special emphasis on the possible implications in cardiovascular disease. We discuss its possible role in inflammation, vasomotor function, thrombosis, angiogenesis, vascular aging and vascular rhythm. We also briefly review the clinical implications of these lines of research.

Peroxisome proliferator-activated receptor pathway gene polymorphism associated with extent of coronary artery disease in patients with type 2 diabetes in the bypass angioplasty revascularization investigation 2 diabetes trial

BACKGROUND

Coronary artery disease (CAD) is the major cause of death in patients with type 2 diabetes mellitus. Although demographic and clinical factors associated with extent of CAD in patients with diabetes mellitus have been described, genetic factors have not. We hypothesized that genetic variation in peroxisome proliferator-activated receptor (PPAR) pathway genes, important in diabetes mellitus and atherosclerosis, would be associated with extent of CAD in patients with diabetes mellitus.

METHODS AND RESULTS

We genotyped 1043 patients (702 white, 175 blacks) from the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) genetic cohort for 3351 variants in 223 PPAR pathway genes using a custom targeted-genotyping array. Angiographic end points were determined by a core laboratory. In whites, a single variant (rs1503298) in TLL1 was significantly (P=5.5 × 10(-6)) associated with extent of CAD, defined as number of lesions with percent diameter stenosis ≥20%, after stringent Bonferroni correction for all 3351 single nucleotide polymorphisms. This association was validated in the diabetic subgroups of 2 independent cohorts, the Translational Research Investigating Underlying Disparities in Acute Myocardial Infarction Patients' Health Status (TRIUMPH) post-myocardial infarction registry and the prospective Family Heart Study (FHS) of individuals at risk for CAD. TLL1rs1503298 was also significantly associated with extent of severe CAD (≥70% diameter stenosis; P=3.7 × 10(-2)) and myocardial jeopardy index (P=8.7 × 10(-4)). In general linear regression modeling, TLL1rs1503298 explained more variance of extent of CAD than the previously determined clinical factors.

CONCLUSIONS

We identified a variant in a single PPAR pathway gene, TLL1, that is associated with the extent of CAD independently of clinical predictors, specifically in patients with type 2 diabetes mellitus and CAD. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00006305.

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.

PPAR Genomics and Pharmacogenomics: Implications for Cardiovascular Disease

The peroxisome proliferator-activated receptors (PPARs) consist of three related transcription factors that serve to regulate a number of cellular processes that are central to cardiovascular health and disease. Numerous pharmacologic studies have assessed the effects of specific PPAR agonists in clinical trials and have provided insight into the clinical effects of these genes while genetic studies have demonstrated clinical associations between PPAR polymorphisms and abnormal cardiovascular phenotypes. With the abundance of data available from these studies as a background, PPAR pharmacogenetics has become a promising and rapidly advancing field. This review focuses on summarizing the current state of understanding of PPAR genetics and pharmacogenetics and the important implications for the individualization of therapy for patients with cardiovascular diseases.

Genetic polymorphisms of peroxisome proliferator-activated receptors and the risk of cardiovascular morbidity and mortality in a community-based cohort in washington county, Maryland

The primary aim of this study was to examine prospectively the associations between 5 peroxisome proliferator-activated receptor (PPAR) single nucleotide polymorphisms (SNPs) and cardiovascular morbidity and mortality in a community-based cohort study in Washington County, Maryland. Data were analyzed from 9,364 Caucasian men and women participating in CLUE-II. Genotyping on 5 PPAR polymorphisms was conducted using peripheral DNA samples collected in 1989. The followup period was from 1989 to 2003. The results showed that there were no statistically significant associations between the PPAR SNPs and cardiovascular deaths or events. In contrast, statistically significant age-adjusted associations were observed for PPARG rs4684847 with both baseline body mass and blood pressure, and for PPARG rs709158, PPARG rs1175543, and PPARD rs2016520 with baseline cholesterol levels. Future studies should be conducted to confirm these findings and to explore the associations in populations with greater racial and ethnic diversity.

Peroxisome proliferator-activated receptor gamma polymorphisms and coronary heart disease

Single nucleotide polymorphisms (SNPs) in the peroxisome proliferator-activated receptor γ (PPARG) gene have been associated with cardiovascular risk factors, particularly obesity and diabetes. We assessed the relationship between 4 PPARG SNPs (C-681G, C-689T, Pro12Ala, and C1431T) and coronary heart disease (CHD) in the PRIME (249 cases/494 controls, only men) and ADVANCE (1,076 cases/805 controls, men or women) studies. In PRIME, homozygote individuals for the minor allele of the PPARG C-689T, Pro12Ala, and C1431T SNPs tended to have a higher risk of CHD than homozygote individuals for the frequent allele (adjusted OR [95% CI] = 3.43 [0.96–12.27], P = .058, 3.41 [0.95–12.22], P = .060 and 5.10 [0.99–26.37], P = .050, resp.). No such association could be detected in ADVANCE. Haplotype distributions were similar in cases and control in both studies. A meta-analysis on the Pro12Ala SNP, based on our data and 11 other published association studies (6,898 CHD cases/11,287 controls), revealed that there was no evidence for a significant association under the dominant model (OR = 0.99 [0.92–1.07], P = .82). However, there was a borderline association under the recessive model (OR = 1.29 [0.99–1.67], P = .06) that became significant when considering men only (OR = 1.73 [1.20–2.48], P = .003). In conclusion, the PPARG Ala12Ala genotype might be associated with a higher CHD risk in men but further confirmation studies are needed.

Retinoid X receptor heterodimer variants and cardiovascular risk factors

Nuclear receptors are transcription factors that can be activated by specific ligands. Recent progress has shown that retinoid X receptor (RXR) and its heterodimerization partners, including peroxisome proliferator-activated receptors, regulate many important genes involved in energy homeostasis and atherosclerosis, and should be promising therapeutic targets of metabolic syndrome. RXR heterodimers regulate a number of complex cellular processes, and genetic studies of RXR heterodimers have provided important clinical information in addition to knowledge gained from basic research. Genetic variants of RXR heterodimers were screened and investigated, and some variants were shown to have a considerable impact on metabolic disorders, including phenotypic components of familial combined hyperlipidemia. The combined efforts of basic and clinical science regarding nuclear receptors have achieved significant progress in unraveling the inextricably linked control system of energy expenditure, lipid and glucose homeostasis, inflammation, and atherosclerosis.This review summarizes the current understanding regarding RXR heterodimers based on their human genetic variants, which will provide new clues to uncover the background of multifactorial disease, such as metabolic syndrome or familial combined hyperlipidemia.

PPARgamma Pro12Ala polymorphism and risk of acute coronary syndrome in a prospective study of Danes

Background

Acute coronary syndrome (ACS) is a major cause of morbidity and mortality in the western world. Peroxisome proliferator-activated receptor γ (PPARγ) plays a key role in the regulation of the energy balance, adipocyte differentiation and lipid biosynthesis. The aim was to investigate if the polymorphism PPARγ2 Pro¹²Ala, which encodes a less efficient transcription factor, was associated with risk of acute coronary disease and if there were interactions between this polymorphism and factors that modify PPARγ activity, such as alcohol intake, smoking, and use of non-steroidal anti-inflammatory medicine.

Methods

A case-cohort study including 1031 ACS cases and a sub-cohort of 1703 persons was nested within the population-based prospective study Diet, Cancer and Health of 57,053 individuals.

Results

Homozygous male variant allele carriers of PPARγ2 Pro¹²Ala were at higher risk of ACS (HR = 2.12, 95% CI: 1.00–4.48) than homozygous carriers of the Pro-allele. Among men, there was a statistically significant interaction between genotypes and alcohol intake such that homozygous variant allele carriers with a low alcohol intake were at higher risk of ACS (HR = 25.3, CI: 16.5–38.7) compared to homozygous common allele carriers (p for interaction < 0.0001). Overall, the association was only observed among homozygous variant allele carriers. Thus, all the observed associations were obtained in subgroups including small numbers of cases. It is therefore possible that the observed associations were due to chance.

Conclusion

In the present study, there were no consistent associations between PPARγ Pro¹²Ala and risk of ACS, and no consistent interaction with alcohol, BMI, NSAID or smoking in relation to ACS.

PPAR gamma variant influences angiographic outcome and 10-year cardiovascular risk in male symptomatic coronary artery disease patients

OBJECTIVE

Activation of peroxisome proliferator-activated receptor (PPAR)-gamma signaling influences metabolic profiles and the propensity toward inflammation. Small-molecule stimulation of PPARgamma is investigated for secondary prevention of cardiovascular disease. The common PPARgamma Pro12Ala variant has functional and prognostic consequences. A protective effect of the 12Ala-allele carriership on diabetes and myocardial infarction in healthy populations has been suggested. The relevance of this pathway also needs exploration in patients with manifest vascular disease. We investigated the effects of carriership of the Pro12Ala variant on angiographic and cardiovascular event outcomes in male patients with symptomatic coronary artery disease (CAD).

RESEARCH DESIGN AND METHODS

The Regression Growth Evaluation Statin Study (REGRESS) cohort was genotyped for the Pro12Ala variant (rs1801282). Ten-year follow-up was derived from nation-wide registries, and risks were estimated using proportional hazards. Quantitative coronary angiography measurements were obtained and relations with genotype estimated using a generalized linear model.

RESULTS

Genotypes ascertained (n = 679) comprised 540 (80%) Pro/Pro, 126 (19%) Pro/Ala, and 13 (2%) Ala/Ala subjects. The 12Ala allele was associated with less extensive focal (P = 0.001) and diffuse (P = 0.002) atherosclerosis and lower 10-year cardiovascular risk. Hazard ratios were 0.10 (95% CI 0.01-0.70, P = 0.02) for ischemic heart disease and 0.24 (0.08-0.74, P = 0.013) for vascular death, per each added copy of 12Ala, respectively.

CONCLUSIONS

Carriers of the 12Ala allele of PPARgamma have less widespread CAD and are considerably protected against 10-year (cardio)vascular morbidity and mortality. These long-term findings in patients with manifest CAD support an important role of PPARgamma in determining vascular risk.

PPARγ2 polymorphism and human health

The nuclear hormone receptor peroxisome proliferator activated receptor gamma (PPARγ) is an important transcription factor regulating adipocyte differentiation, lipid and glucose homeostasis, and insulin sensitivity. Numerous genetic mutations of PPARγ have been identified and these mutations positively or negatively regulate insulin sensitivity. Among these, a relatively common polymorphism of PPARγ, Pro12Ala of PPARγ2, the isoform expressed only in adipose tissue has been shown to be associated with lower body mass index, enhanced insulin sensitivity, and resistance to the risk of type 2 diabetes in human subjects carrying this mutation. Subsequent studies in different ethnic populations, however, have revealed conflicting results, suggesting a complex interaction between the PPARγ2 Pro12Ala polymorphism and environmental factors such as the ratio of dietary unsaturated fatty acids to saturated fatty acids and/or between the PPARγ2 Pro12Ala polymorphism and genetic factors such as polymorphic mutations in other genes. In addition, this polymorphic mutation in PPARγ2 is associated with other aspects of human diseases, including cancers, polycystic ovary syndrome, Alzheimer disease and aging. This review will highlight findings from recent studies.

Genotype-phenotype associations: modulation by diet and obesity

Changes in diet are likely to reduce chronic disorders, but after decades of active research and heated discussion, the question still remains: what is the optimal diet to achieve this elusive goal? Is it a low-fat diet, as traditionally recommended by multiple medical societies? Or a high monounsaturated fat (MUFA) diet as predicated by the Mediterranean diet? Perhaps a high polyunsaturated fat (PUFA) diet based on the cholesterol-lowering effects? The right answer may be all of the above but not for everybody. A well-known phenomenon in nutrition research and practice is the dramatic variability in interindividual response to any type of dietary intervention. There are many other factors influencing response, and they include, among many others, age, sex, physical activity, alcohol, and smoking as well as genetic factors that will help to identify vulnerable populations/individuals that will benefit from a variety of more personalized and mechanistic-based dietary recommendations. This potential could and needs to be developed within the context of nutritional genomics that in conjunction with systems biology may provide the tools to achieve the holy grail of dietary prevention and therapy of chronic diseases and cancer. This approach will break with the traditional public health approach of "one size fits all." The current evidence based on nutrigenetics has begun to identify subgroups of individuals who benefit more from a low-fat diet, whereas others appear to benefit more from high MUFA or PUFA diets. The continuous progress in nutrigenomics will allow some time in the future to provide targeted gene-based dietary advice.

PPAR transcriptional activator complex polymorphisms and the promise of individualized therapy for heart failure

The PPAR gene pathway consists of interrelated genes that encode transcription factors, enzymes, and downstream targets which coordinately act to regulate cellular processes central to glucose and lipid metabolism. The pathway includes the PPAR genes themselves, other class II nuclear hormone receptor transcription factors within the PPAR family, PPAR co-activators, PPAR co-repressors, and downstream metabolic gene targets. This review focuses on the transcription factors that comprise the PPAR transcriptional activator complex--the PPARs (PPARalpha, PPARbeta, or PPARgamma), PPAR heterodimeric partners, such as RXRalpha, and PPAR co-activators, such as PPARgamma coactivator 1alpha (PGC-1alpha) and the estrogen-related receptors (ERRalpha, ERRbeta, and ERRgamma). These transcription factors have been implicated in the development of myocardial hypertrophy and dilated cardiomyopathy as well as response to myocardial ischemia/infarction and, by association, ischemic cardiomyopathy. Human expression studies and animal data are presented as the background for a discussion of the emerging field of pharmacogenetics as it applies to these genes and the consequent implications for the individualization of therapy for patients with heart failure.

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.

Vascular risk factors in South Asians

South Asians originate from the Indian sub-continent (India, Pakistan, Bangladesh, Sri Lanka and Nepal) and represent one fifth of the world's population. Several studies suggested that South Asians have an increased risk of developing coronary heart disease (CHD) when compared with European populations. We review the role of traditional and emerging risk factors in the increased CHD risk in South Asians. The high prevalence of insulin resistance and type 2 diabetes mellitus in South Asians may be a major cause for their elevated vascular risk. However, other established and emerging risk factors are also overrepresented in South Asians. Large-scale prospective studies could determine the relative contribution of established and emerging vascular risk factors in South Asians. There is an urgent need for trials in South Asians that will evaluate clinical outcomes following treatment of these risk factors.

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.

Peroxisome proliferator-activated receptors and inflammation: take it to heart

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors acting as key regulators of lipid metabolism as well as modulators of inflammation. The role of PPARalpha and PPARgamma in cardiac ischaemia-reperfusion injury, infarct healing and hypertrophy is the subject of intense research. Due to the later development of PPARdelta-specific ligands, the role of this PPAR isoform in cardiac disease remains to be established. Although many studies point to salutatory effects of PPAR ligands in cardiac disease, the exact molecular mechanism is still largely unsolved. Both the metabolic (via transactivation) and the more recently discovered anti-inflammatory (via transrepression) effects of PPARs are likely to play a role. In this review the reported, and sometimes contradictory, effects of PPAR ligands on ischaemia-reperfusion, infarct healing and cardiac hypertrophy are critically evaluated. In particular the role of inflammation in these disease processes, the ability of PPARs to interfere with pro-inflammatory processes, and the mechanisms of transrepression are discussed. Currently, the significance of PPARs as therapeutic targets in cardiovascular disease is receiving widespread attention. Accordingly, detailed understanding of the mechanisms controlling the activity of these nuclear hormone receptors is essential.

Ala12 variant of the peroxisome proliferator-activated receptor-gamma gene (PPARG) is associated with higher polyunsaturated fat in adipose tissue and attenuates the protective effect of polyunsaturated fat intake on the risk of myocardial infarction

BACKGROUND

Intake of polyunsaturated fat is protective against the development of coronary heart disease. Less is known about the genetic variation modulating this association. The Ala12 allele of the peroxisome proliferator-activated receptor-gamma gene (PPARG) decreases the lipolysis of triacylglycerols in adipose tissue, which results in the accumulation of fatty acids in adipocytes.

OBJECTIVE

We aimed to determine whether the Pro12Ala polymorphism interacts with polyunsaturated fat intake to affect the risk of myocardial infarction (MI).

DESIGN

Cases (n = 1805) with a first nonfatal acute MI and population-based controls matched by age, sex, and area of residence (n = 1805) living in Costa Rica were genotyped for the PPARG Pro12Ala genetic polymorphism. Polyunsaturated fat intake was determined by use of a validated food-frequency questionnaire and by gas chromatography analysis of adipose tissue. Odds ratios and 95% CIs for MI were estimated by use of logistic regression.

RESULTS

The relative allele frequencies of the Ala12 allele were 10% in controls and 11% in cases. Odds ratios (95% CI) for MI per each 5% increase in energy from polyunsaturated fat were 0.66 (0.53, 0.82) in Pro12/Pro12 subjects and 0.93 (0.61, 1.42) in carriers of the Ala12 allele (P for interaction = 0.03). Increments (95% CI) of polyunsaturated fat in adipose tissue per 5% increment in dietary intake were 5.4% (4.9%, 5.9%) in Pro12/Pro12 homozygotes, 6.9% (6.0%, 7.9%) in Pro12/Ala12 heterozygotes, and 7.7% (3.2%, 12.2%) in Ala12/Ala12 homozygotes (P for interaction = 0.016).

CONCLUSIONS

The protective effect of polyunsaturated fat intake on MI is attenuated in carriers of the Ala12 allele of PPARG.

Single nucleotide polymorphisms at the adiponectin locus and risk of coronary heart disease in men and women

OBJECTIVE

The objective was to examine the association of 5 common single nucleotide polymorphisms (SNPs) at the adiponectin locus with risk of coronary heart disease (CHD) in men and women.

METHODS AND PROCEDURES

We genotyped five common SNPs in the adiponectin gene (rs266729, -11365C>G; rs822395, -4034A>C; rs822396, -3964A>G; rs2241766, +45T>G; and rs1501299, +276G>T) in men (Health Professionals Follow-up Study) and women (Nurses' Health Study) in a nested case control setting. Among participants free of cardiovascular disease at baseline, 266 men and 249 women developed non-fatal myocardial infarction or fatal CHD during 6 and 8 years of follow-up, respectively. In addition, 564 men had coronary artery bypass graft surgery or percutaneous transluminal coronary angioplasty. Using risk set sampling, controls were selected 2:1 matched on age, smoking, and date of blood draw.

RESULTS

The -4034CC genotype was related to an increased risk of non-fatal myocardial infarction or fatal CHD compared with the AA genotype [relative risk (RR), men, 1.69; 95% confidence interval (CI), 0.99 to 2.89; women, 2.04; 95% CI, 1.20 to 3.49); however, this genotype was not related to risk of coronary artery bypass graft surgery or percutaneous transluminal coronary angioplasty or to plasma adiponectin levels. Other SNPs or haplotypes defined by the 5 SNPs were not consistently related to risk of CHD in men and women or to plasma adiponectin levels.

DISCUSSION

Our study does not support the hypothesis that these 5 common SNPs in the adiponectin gene play an important role in the development of CHD among men and women, although we cannot exclude an association between the -4034CC genotype and risk of CHD.

ENPP1 gene, insulin resistance and related clinical outcomes

PURPOSE OF REVIEW

Insulin resistance plays a significant role in both morbidity and mortality of the general population. Understanding the molecular mechanisms of insulin resistance would help the identification of at-risk individuals in the presymptomatic stage, and the discovery of novel and more effective treatments. The transmembrane glycoprotein ectonucleotide pyrophosphatase phosphodiesterase 1 (ENPP1) inhibits insulin receptor signalling and has recently emerged as a key player in the development of insulin resistance. This review will summarize data available on the relationship between ENPP1 and insulin resistance.

RECENT FINDINGS

Overexpression of ENPP1 in insulin target tissues is an early, intrinsic defect observed in human insulin resistance. A missense ENPP1 single nucleotide polymorphism, K121Q, has been recently described with the Q121 variant being a stronger inhibitor than K121 of insulin receptor function. In addition, the Q121 variant has been repeatedly associated with insulin resistance and related abnormalities including body weight changes, type 2 diabetes and macrovascular complications, thus suggesting a pleiotropic role of the ENPP1 gene on several metabolic abnormalities.

SUMMARY

A deep understanding of ENPP1 mode of action and the mechanisms regulating its expression and function are likely to provide new tools for early identification and treatments of patients at risk for the devastating clinical outcomes related to insulin resistance.

Biomarkers of obesity and subsequent cardiovascular events

Obesity is a major risk factor for cardiovascular diseases, but the mechanisms for increased cardiovascular risk in obesity are still unclear. Inflammation and increased oxidative stress are two potential mechanisms proposed to play a major role in the morbidity associated with obesity. Studies that investigate these mechanisms rely on biomarkers, but validated biomarkers for obesity-related cardiovascular outcomes are lacking. By finding optimal biomarkers, diagnostic criteria for cardiovascular diseases can be refined in the obese beyond "traditional" risk factors to identify early pathologic processes. The objective of this review is to identify potential early biomarkers resulting from obesity and associated with cardiovascular disease. Studies were initially identified through the search engine PubMed by using the keywords "obesity" and "biomarker." Subsequently, combinations of the keywords "obesity," "biomarker," "cardiovascular risk," "adipose tissue," "adipokine," "adipocytokine," and "oxidative stress" were used. The SOURCE database and Online Mendelian Inheritance in Man (OMIM) were used to obtain more information on the biomarkers. Results of the searches yielded a large number of potential biomarkers that occur in obesity and which either correlate with traditional cardiovascular risk factors or predict subsequent cardiovascular events. Several biomarkers are promising regarding their biologic properties, but they require further validation in humans.

No Association of Pro12Ala Polymorphism of PPAR-.GAMMA. Gene With Coronary Artery Disease in Korean Subjects

BACKGROUND

Peroxisome proliferator-activated receptor (PPAR)-gamma, a member of the nuclear hormone receptor family, which is involved in the differentiation of adipose tissue, is reported to be associated with the pathogenesis of type 2 diabetes mellitus, insulin resistance and atherosclerosis. Whether the prevalence of coronary artery disease (CAD) is associated with Pro12Ala polymorphism in exon B of PPAR-gamma was investigated in Korean adults.

METHODS AND RESULTS

The study was conducted in 267 subjects (158 males, 109 females, mean age 58 years) who underwent coronary angiography because of chest pain. Cardiovascular risk factors, such as blood pressure, body mass index (BMI), fasting blood sugar and serum lipid profiles, were assessed in all subjects, who were divided into 4 groups according to the number of stenosed coronary arteries: normal, 1-vessel, 2-vessel and 3-vessel disease. Genotyping of Pro12Ala polymorphism was done with real-time polymerase chain reaction. Allelic frequency for proline was 0.955 and 0.045 for alanine, which was in Hardy-Weinberg equilibrium (p=0.74). One hundred and seventeen subjects (43.8%) had normal coronary arteries, 88 (33%) had 1-vessel disease, 39 (14.6%) had 2-vessel disease and 23 (8.6%) had 3-vessel disease. When the cardiovascular risk factors were compared among the 4 groups, there were no meaningful differences except for age and FBG levels, which were significant even after adjustment for age and BMI. There were no significant differences in the prevalence or severity of CAD according to the different genotypes of Pro12Ala, and in logistic regression analysis Pro12Ala polymorphism was not a predictor for CAD.

CONCLUSIONS

There was no significant association between Pro12Ala polymorphism in exon B of PPAR-gamma and prevalence or severity of CAD in Korean adults. Further studies on the correlation between Pro12Ala polymorphism and CAD should be carried out in a larger Korean population in the future.

Association between Pro12Ala polymorphism of peroxisome proliferator-activated receptor-gamma 2 and myocardial infarction in the Chinese Han population

BACKGROUND

Peroxisome proliferator-activated receptor-gamma 2 (PPAR-gamma 2) is a nuclear receptor that plays an important role in adipocyte differentiation, energy metabolism, and homeostasis. The Pro12Ala polymorphism of PPAR-gamma 2 is associated with decreased risk of diabetes mellitus. Presumably, it may have a protective effect on myocardial infarction (MI).

HYPOTHESIS

The purpose of the study was to explore the association between the Pro12Ala polymorphism and the risk of MI in the Chinese population.

METHODS

The Pro12Ala polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism among 844 subjects, including 218 patients with MI and 626 controls. Clinical parameters such as fasting serum total cholesterol, triglycerides, and plasma glucose were detected by autoanalyzer assay. Waist circumference, weight, height, and blood pressure (BP) were measured and body mass index (BMI) was calculated.

RESULTS

The frequencies of the Ala allele in the MI and control groups were 0.053 and 0.032, respectively. There was a significant difference in genotype and allele frequency distribution between the two groups (after adjustment for age, gender, BP, fasting plasma glucose, total cholesterol, triglycerides, and smoking, odds ratio [OR] = 2.51, 95% confidence interval [CI]: 1.26-5.00, p = 0.009). In the group with MI, the difference in frequency of the Ala allele in women (0.241) compared with that of men (0.056) was significant (OR = 4.29, 95% CI: 1.96-9.37, p < 0.001). There was no relationship between the Pro12Ala polymorphism and waist circumference, weight, BMI, BP, or triglycerides (p > 0.05).

CONCLUSIONS

Our study suggests that Pro12Ala polymorphism is associated with increased risk of MI.

The PPAR genes, cardiovascular disease and the emergence of PPAR pharmacogenetics

The peroxisome proliferator-activated receptors (PPARs) comprise a group of related transcription factors that serve to regulate a number of cellular processes that are central to cardiovascular health and disease. Two large bodies of work strongly implicate the PPARs as key factors in normal cardiovascular physiology and in cardiovascular pathophysiology: i) studies demonstrating associations between PPAR and abnormal cardiovascular phenotypes; and ii) pharmacological studies assessing the effects of specific PPAR agonists in clinical trials. With the abundance of data available from these studies as a background, PPAR pharmacogenetics has become a promising and rapidly-advancing field. This review summarises the current state of understanding of PPAR pharmacogenetics and its profound implications for the individualisation of therapy for patients with a diverse group of cardiovascular diseases.

Improved prediction of early-onset coronary artery disease using APOE ε4, BChE-K, PPARγ2 Pro12 and ENOS T-786C in a polygenic model

OBJECTIVES

Coronary artery disease (CAD) is often polygenic due to multiple mutations that contribute small effects to susceptibility. Since most prior studies only evaluated the contribution of single candidate genes, we therefore looked at a combination of genes in predicting early-onset CAD [apolipoprotein E (APOE) epsilon4, butyrylcholinesterase (BChE) K, peroxisome proliferator-activated receptor gamma2 (PPARgamma2) Pro12Ala and endothelial nitric oxide synthase (ENOS) T-786C].

DESIGN AND METHODS

We examined the frequencies, individually and in combination, of all four alleles among patients with early-onset CAD (n = 150; <50 years), late-onset CAD (n = 150; >65 years) and healthy controls (n = 150, age range 47-93 years). Differences in the proportion of subjects in each group with the given gene combination were assessed and likelihood ratios (LR) were calculated using logistic regression to combine the results of multiple genes.

RESULTS

Early-onset CAD patients had increased, but non-significant, frequencies of PPARgamma2 Pro12/Pro12 (P = 0.39) and ENOS T-786C (P = 0.72), while BChE-K was only significantly higher in early-onset CAD patients compared to controls (P = 0.03). There were significantly more APOE epsilon4 alleles alone (P = 0.02) or in combination with BChE-K (P = 0.02) among early-onset CAD patients compared to late-onset CAD ones or controls. When combined, there was a higher prevalence of all four alleles in early-onset CAD (early-onset CAD patients: 10.7%, late-onset CAD patients: 3.3% and controls: 2.7%, P = 0.01). LR for early-onset CAD for a single allele was relatively small (1.08 for PPARgamma2 to 1.70 for APOE epsilon4). This increased to 2.78 (1.44-5.37) when combining all four alleles, therefore increasing the pre-test probability of CAD from 5% to a post-test probability of 12.7%.

CONCLUSIONS

While any single mutation causes only a mildly increased LR (none > 1.7), in combination, the likelihood of early-onset CAD increased to 2.78 with four mutations. The genetics of early-onset CAD appear to be multifactorial, requiring polygenic models to elucidate risk.