Fetal and maternal peroxisome proliferator-activated receptor gamma2 Pro12Ala does not influence birth weight

The association between the peroxisome proliferator-activated receptor (PPAR)gamma2 Pro12Ala polymorphism and insulin resistance is reported to depend on low birth weight. Low birth weight itself has been linked to type 2 diabetes and cardiovascular diseases in adulthood. We assessed whether the PPARgamma2 Pro12Ala polymorphism determines body size at birth and whether metabolic differences between the genotypes are already detectable in the newborn. This study was conducted at the obstetrics department of the Charité, Berlin, Germany. One thousand nine hundred thirty white woman/child pairs were consecutively included and genotyped. The newborn's weight, length, and head circumference were measured. Total glycated hemoglobin in blood served as a surrogate of fetal insulin resistance and glucose use. We found that neither the fetal nor the maternal Pro12Ala genotype determined body size or total glycated hemoglobin at birth. The results suggest that the PPARgamma2 Pro12Ala polymorphism is not relevant for intrauterine growth. Previously reported effects of PPARgamma2 Pro12Ala on insulin resistance seem to arise later in life.     

Pro12Ala substitution in the peroxisome proliferator-activated receptor-gamma is associated with increased leptin levels in women with type-2 diabetes mellitus

OBJECTIVE: To analyze the relationship between the peroxisome proliferator-activated receptor-gamma (PPARgamma2) Pro12Ala variant and type-2 diabetes mellitus and its correlation with some cytokine determinants of insulin resistance such as tumor necrosis factor (TNF)-alpha and leptin. METHODS: The PPARgamma2 Pro12Ala genetic polymorphism was studied in 167 type-2 diabetic patients and 63 healthy controls. Serum leptin and plasma-soluble TNF-R2 were measured. RESULTS: Women carriers of the Pro12Ala mutation exhibited higher leptin levels than women non-carriers (median 31.4 vs. 17.5 ng/ml; p < 0.005). sTNF-R2 levels did not show differences between the two genotypes. Analysis by the multiple linear regression model of leptin-body mass index controlled by the PPARgamma2 genotype showed that leptin levels were determined by the Pro12Ala mutation in type-2 diabetic women but not in men. CONCLUSIONS: PPARgamma2 seems to be implicated in leptin homeostasis in type-2 diabetic women.     

PPARgamma2 Pro12Ala polymorphism in relation to free fatty acids concentration and composition in lean healthy Czech individuals with and without family history of diabetes type 2

Free fatty acids (FFAs) are natural ligands of the PPARgamma2 receptor. FFA plasma concentration and composition may represent one of the factors accounting for high heterogeneity of conclusions concerning the effect of the Pro12Ala on BMI, insulin sensitivity or diabetes type 2 (DM2) susceptibility. Our objective was to investigate the relation and possible interactions between the Pro12Ala polymorphism and FFA status, metabolic markers, and body composition in 324 lean nondiabetic subjects (M/F: 99/225; age 32+/-11 years; BMI 23.9+/-4.0 kg/m(2)) with and without family history of DM2. Family history of DM2 was associated with lower % PUFA and slightly higher % MUFA. The presence of Pro12Ala polymorphism was not associated with fasting plasma FFA concentration or composition, anthropometric or metabolic markers of glucose and lipid metabolism in tested population. However, the interaction of carriership status with FFA levels influenced the basal glucose levels, insulin sensitivity and disposition indices, triglycerides, HDL-cholesterol and leptin levels, especially in women. The metabolic effects of 12Ala carriership were influenced by FFA levels - the beneficial role of 12Ala was seen only in the presence of low concentration of plasma FFA. Surprisingly, a high PUFA/SFA ratio was associated with lower insulin sensitivity, the protective effect of 12Ala allele was apparent in subjects with family history of DM2. On the basis of our findings and published data we recommend the genotyping of diabetic patients for Pro12Ala polymorphism of the PPARgamma2 gene before treatment with thiazolidinediones and education of subjects regarding diet and physical activity, which modulate metabolic outcomes.     

Influence of the PPAR-gamma2 Pro12Ala and ACE I/D polymorphisms on insulin sensitivity and training effects in healthy offspring of type 2 diabetic subjects.

Aerobic endurance training improves insulin sensitivity, and is of great importance in the prevention and treatment of type 2 diabetes. The improvement in insulin sensitivity and cardiovascular function through exercise is highly variable among individuals, and is probably partly determined by genetic components. This study evaluated the peroxisome proliferation-activated receptor-gamma2 ( PPAR-gamma2) Pro12Ala polymorphism and the angiotensin converting enzyme ( ACE) I/D polymorphism with respect to any potential influence that these highly prevalent polymorphisms may impose on changes in insulin sensitivity and maximal aerobic capacity induced by exercise. Seventy-nine healthy first-degree relatives of type 2 diabetic patients were compared to a control group consisting of 54 subjects without any family history of type 2 diabetes. All subjects had a normal OGTT. The groups were comparable with respect to age (34 +/- 7 vs. 33 +/- 7 years), gender ((m/f) 43/36 vs. 30/24) and BMI (25.7 +/- 2.6 vs. 25.3 +/- 2.5 kg/m (2)); p (all) = NS. Furthermore, a subgroup of 29 offspring and 17 control subjects were engaged in a standardized training program lasting ten weeks. Insulin sensitivity (hyperinsulinemic euglycemic clamp technique) and VO (2)max (exhaustive exercise test) was assessed before and after the training period. We will demonstrate the allelic frequency of the Ala-allele of the Pro12Ala polymorphism to be lower in offspring to type 2 diabetic patients (13.3 %) compared to control subjects (21.3 %); p < 0.05. In offspring only, the Pro12Ala polymorphism of the PPAR-gamma2 gene appeared to enhance weight changes brought about by exercise (Deltaweight = - 0.3 +/- 1.4 kg vs. - 1.8 +/- 1.8 kg; p < 0.05; (Pro/Pro vs. Pro/Ala + Ala/Ala) - suggesting possible gene-environment or gene-gene interactions. The ACE I/D polymorphism was not of significant importance in determining the capability of responding to exercise in terms of improvement in insulin sensitivity or maximal aerobic capacity.     

Molecular mechanism of insulin resistance and obesity

Obesity and insulin resistance have been recognized as leading causes of major health issues. We have endeavored to depict the molecular mechanism of insulin resistance, focusing on the function of adipocyte. We have investigated a role of PPARgamma on the pathogenesis of Type II diabetes. Heterozygous PPARgamma-deficient mice were protected from the development of insulin resistance due to adipocyte hypertrophy under a high-fat diet. Moreover, a Pro12Ala polymorphism in the human PPARgamma2 gene was associated with decreased risk of Type II diabetes in Japanese. Taken together with these results, PPARgamma is proved to be a thrifty gene mediating Type II diabetes. Pharmacological inhibitors of PPARgamma/RXR ameliorate high-fat diet-induced insulin resistance in animal models of Type II diabetes. We have performed a genome-wide scan of Japanese Type 2 diabetic families using affected sib pair analysis. Our genome scan reveals at least 9 chromosomal regions potentially harbor susceptibility genes of Type II diabetes in Japanese. Among these regions, 3q26-q28 appeared to be very attractive one, because of the gene encoding adiponectin, the expression of which we had found enhanced in insulin-sensitive PPARgamma-deficient mice. Indeed, the subjects with the G/G genotype of SNP276 in the adiponectin gene were at increased risk for Type II diabetes compared with those having the T/T genotype. The plasma adiponectin levels were lower in the subjects with the G allele, suggesting that genetically inherited decrease in adiponectin levels predispose subjects to insulin resistance and Type II diabetes. Our work also confirmed that replenishment of adiponectin represents a novel treatment strategy for insulin resistance and Type II diabetes using animal models. Further investigation will be needed to clarify how adiponectin exerts its effect and to discover the molecular target of therapies.     

PPAR-gamma2 Pro12Ala polymorphism in the population of obese and non-obese men of the city of Wroclaw

INTRODUCTION: The aim of this study was to examine the association of Pro12Ala PPARgamma2 polymorphism with anthropometric and biochemical parameters defining the risk for the development of metabolic syndrome in a healthy population of men. MATERIAL AND METHODS: The study group consisted of 176 healthy men, aged 25-65 years (average 54.16 years). Polymorphisms of the PPAR-g gene (Pro12Ala, Ala12Ala, Pro12Pro) were explored using the PCR-RFLP method. Plasma glucose, insulin, total cholesterol, LDL, HDL and TG were measured using commercially available kits. RESULTS: The genotypic distribution of the Pro12Ala polymorphism was as follows: Pro/Ala 69.8% (n = 123), Ala/Ala 28.4% (n = 50) and Pro/Pro 1.8% (n = 3). The Pro12Ala and Ala12Ala subjects did not differ in any of the measured variables. The non-obese (BMI < 30 kg/m(2), n = 117) and obese subpopulations (BMI > 30 kg/m(2), n = 56) did not significantly differ in the distribution of the genotypes. In the nonobese subpopulation, the homozygous Ala12 carriers (n = 38, 32.4%) had higher systolic blood pressure, plasma triglycerides, insulin levels and HOMA-IR. CONCLUSIONS: We conclude that despite the high frequency of the Ala allele at the PPAR-gamma2 gene in our population of Polish men, the Ala12 allele does not appear to improve insulin sensitivity or have an influence on the occurrence of obesity. It remains to be explained by larger studies if this polymorphism carries any risk of the development of metabolic abnormalities in non-obese men.     

Evidence for greater oxidative substrate flexibility in male carriers of the Pro 12 Ala polymorphism in PPARgamma2.

The Pro12Ala polymorphism of the peroxisome proliferator-activated receptor gamma2 (PPARgamma2) gene is associated with reduced type 2 diabetes risk and increased insulin sensitivity. It is possible that the oxidative shift from lipid to glucose as a fuel is more efficient in Ala allele carriers. To test this hypothesis, we examined carbohydrate and lipid oxidation by indirect calorimetry in lean, glucose tolerant subjects with (X/Ala, n = 25) and without the Pro12Ala polymorphism (Pro/Pro, n = 73) basally and after insulin stimulation during a 2-hour eugylcaemic hyperinsulinaemic clamp. Insulin sensitivity was non-significantly greater in X/Ala (0.13 +/- 0.01 micromol/kg/min/pM) than in Pro/Pro (0.12 +/- 0.01 micromol/kg/min/pM, p = 0.27). Basally, there were no lipid nor carbohydrate oxidation differences between the groups. Interestingly, the decrease in lipid oxidation during insulin stimulation was significantly greater in male X/Ala (- 0.51 +/- 0.06 mg/kg/min) than in male Pro/Pro (- 0.35 +/- 0.04 mg/kg/min, p = 0.03). No difference was observed in females. Analogously, the change in carbohydrate oxidation in male X/Ala (1.34 +/- 0.2 mg/kg/min) was significantly greater than in male Pro/Pro (1.03 +/- 0.12 mg/kg/min, p = 0.05). The respiratory quotient increased more, but not significantly more, in male X/Ala (0.11 +/- 0.01) than in male Pro/Pro subjects (0.08 +/- 0.01, p = 0.08) but similarly in females. These results indicate that the mechanism by which the Ala allele improves insulin sensitivity might involve enhanced suppression of lipid oxidation permitting more efficient (predominantly non-oxidative) glucose disposal. It is unclear why this could be demonstrated only in males, although gender differences in substrate oxidation are well documented.     

核转录因子PPARγ2的研究进展

过氧化物酶增殖物激活受体γ2(PPARγ2)是一个转录因子,属于核受体超家族的成员之一。其主要在脂肪组织表达,对脂肪细胞分化进行调控。其常见多态性Pro12Ala已发现与肥胖及2型糖尿病关系密切。它也是治疗糖尿病药物噻唑烷二酮类药物（TZDs）作用的靶分子。因此,对其进行代谢调控分子机制的研究,可能有助于对2型糖尿病预防或治疗中起作用的新药物靶位点的发现。 Abstract:Peroxisome proliferator-actived receptor γ2(PPARγ2) is a translation factor that belongs to the superfamily of nuclear receptors.It expresses predominantely in adipose tissue and has a key role in adipocyte differentiation.The common Pro12Ala polymorphism is associated closely with obesity and type 2 diabetes.It is the target molecular of thiazolidinediones which is a novel class of insulin sensitizer.The study of PPARγ2 molecular mechanism of metabolism control may accelerate the finding of new drug targets in prevention and therapeution of type 2 diabetes.     

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.     

The Pro12Ala Polymorphism of the PPARγ2 Gene Regulates Weight from Birth to Adulthood

Objective: The Pro12Ala polymorphism in exon B of peroxisome proliferator‐activated receptor γ 2 (PPARγ2) gene has been related to obesity, insulin resistance, and risk of type 2 diabetes. In this study, the effect of the Pro12Ala polymorphism on long‐term changes in weight and body composition was investigated. Research Methods and Procedures: The Pro12Ala polymorphism was genotyped in 311 subjects who participated in our previous population‐based study. In that study, weight at birth, 7 years, 20 years, and 41 years, and ponderal index at birth and BMI and waist circumference at 41 years were recorded. Results: The Ala12 allele of the PPARγ2 gene was associated with high ponderal index at birth (2.77 ± 0.27 kg/m³ in subjects with the Ala12Ala genotype, 2.79 ± 0.29 kg/m³ in subjects with the Pro12Ala genotype, and 2.63 ± 0.25 kg/m³ in subjects with the Pro12Pro genotype, p = 0.007, adjusted for gender) and weight at 7 years (p = 0.045) and tended to be associated with high birth weight (p = 0.094). Subjects with this allele gained less weight between 7 and 20 years (p = 0.043) and more weight between 20 and 41 years (p = 0.001) and ended up having higher waist circumference (p = 0.040) in adulthood than did subjects with the Pro12Pro genotype. Discussion: We conclude that the Pro12Ala polymorphism of the PPARγ2 gene regulates weight and body composition from utero to adulthood.     

Differential effects of the C1431T and Pro12Ala PPARgamma gene variants on plasma lipids and diabetes risk in an Asian population

We investigated the association of C1431T and Pro12Ala polymorphisms at the peroxisome proliferator-activated receptor gamma (PPARgamma) locus with plasma lipids and insulin resistance-related variables, according to diabetes status, in a large and representative Asian population from Singapore consisting of 2,730 Chinese, 740 Malays, and 568 Indians. Moreover, we estimated the diabetes risk and examined gene-nutrient interactions between these variants and the ratio of polyunsaturated fatty acid to saturated fat (SFA) in determining body mass index (BMI) and fasting insulin. We found differential effects of these gene variants. The Pro12Ala polymorphism was more associated with plasma lipids and fasting glucose concentrations, whereas the C1431T polymorphism was related to the risk of diabetes. Carriers of the 12Ala allele had higher HDL-cholesterol than did Pro12Pro homozygotes (P < 0.05), and the effect of the 12Ala allele on fasting glucose was modified by diabetes status (P < 0.001). After controlling for confounders, carriers of the T allele had decreased risk of diabetes compared with CC homozygotes [odds ratio (OR) 0.73, 95% confidence interval (CI) 0.58-0.93; P = 0.011]; this effect was stronger in Indians (OR 0.38, 95% CI 0.15-0.92; P = 0.032). For both polymorphisms, normal subjects carrying the less prevalent allele had higher BMI (P < 0.05). The PUFA/SFA did not modify the effect of these polymorphisms on BMI or insulin.     

D2 Thr92Ala and PPARγ2 Pro12Ala polymorphisms interact in the modulation of insulin resistance in type 2 diabetic patients

Type 2 deiodinase (D2) converts T4 into its active metabolite T3, an essential step in thyroid metabolism. A Thr92Ala polymorphism in the gene encoding D2 has been inconsistently associated with insulin resistance (IR). Recently, it was reported that the D2 Thr92Ala (rs225014) and the peroxisome proliferator-activated receptor (PPAR) γ2 Pro12Ala (rs1801282) polymorphisms interact in the modulation of metabolic syndrome in nondiabetic subjects. Here, we investigated the effect of both polymorphisms, isolated or in combination, on IR in patients with type 2 diabetes mellitus (DM2). The D2 Thr92Ala and PPARγ2 Pro12Ala polymorphisms were genotyped in 721 DM2 patients. IR was evaluated using the homeostasis model assessment-IR (HOMA(IR)) index in a subgroup of 246 DM2 subjects. The frequencies of D2 Ala92 and PPARγ2 Ala12 variants were 0.390 and 0.074, respectively. Patients carrying D2 Ala/Ala genotype had a higher fasting plasma insulin and HOMA(IR) index as compared to patients carrying Thr/Ala or Thr/Thr genotypes (P = 0.022 and P = 0.001, respectively). A significant synergistic effect was observed between D2 Thr92Ala and PPARγ2 Pro12Ala polymorphisms on HOMA(IR) index, with carriers of both D2 Ala/Ala genotype and PPARγ2 Ala12 allele showing the highest HOMA(IR) values, after adjusting for age, gender, BMI, and use of medication for DM2 (P = 0.010). In conclusion, DM2 patients harboring both D2 Ala/Ala genotype and PPARγ2 Ala12 allele seem to present more severe IR than those with other D2/PPARγ2 genotype combinations. These findings suggest that these polymorphisms interact in the IR modulation, which may constitute a potential therapeutic target.     

Association of soluble epoxide hydrolase gene polymorphism with insulin resistance in type 2 diabetic patients

The insulin resistance found in diabetes is influenced by vascular tone and local blood flow. Endothelial-derived hyperpolarizing factor (EDHF) functions as a potent vasodilator to regulate vascular tone, and its production is regulated by soluble epoxide hydrolase (sEH). In this study, we examined the genotype distribution and allele frequency of sEH gene G860A (Arg287Gln) polymorphism in Japanese subjects (n=499) (non-diabetic subjects, n=205; type 2 diabetic patients, n=294). Also, to accurately evaluate insulin resistance, we performed the euglycemic hyperinsulinemic clamp test for each type 2 diabetic patient (n=86) from whom agreement was obtained, and then examined a possible association of sEH gene G860A polymorphism with insulin resistance status. There was no significant difference in genotype distribution and allele frequency between non-diabetic subjects and type 2 diabetic patients. Interestingly, however, there was close association of sEH gene G860A (Arg287Gln) polymorphism with insulin resistance in type 2 diabetic patients, which was not observed in non-diabetic subjects. These results suggest that sEH and EDHF play some important role in the pathogenesis of insulin resistance found in type 2 diabetes.     

Frequency of the Pro 12Ala polymorphism of PPARgamma2 gene in Ukrainian population and its possible role in development of metabolic syndrome

Frequency of the Pro 12Ala gene polymorphism PPARg2 has been studied in 39 healthy men and 42 men with metabolic syndrome (MS) of the age of 40-65 years in Ukrainian population. The frequencies were 27.9% for 12Ala allele, 32.6% for Pro12Ala, and 4.4% for Ala1Ala that is close to the results of estimation of Czech population. The frequency of 12Ala allele was significantly less--18.4% (p < 0.05) in the persons with MS that corresponds to the pre-established information concerning the patients with diabetes of the 2nd type. A tendency has been detected to the increase of the body mass index in patients with 12Ala allele in the metabolic syndrome group.     

Association of peroxisome proliferator-activated receptor γ Pro12Ala gene polymorphism with type 2 diabetic nephropathy risk in Caucasian population

Abstract

Association of peroxisome proliferator-activated receptor gamma (PPARγ) Pro12Ala gene polymorphism with type 2 diabetic nephropathy (T2DN) risk in Caucasians is still not clear. This investigation was conducted to assess if there was an association between the PPARγ Pro12Ala gene polymorphism and T2DN risk in Caucasians using meta-analysis. The relevant literatures were identified from PubMed, and Cochrane Library on 10 October 2013, and eligible studies were included and synthesized. Six reports including eight studies were recruited into this meta-analysis for the association of the PPARγ Pro12Ala gene polymorphism with T2DN risk in Caucasians. The Pro/Pro genotype was shown to be associated with T2DN risk in Caucasians. However, the Ala/Ala genotype and Ala allele were not associated with T2DN risk in Caucasians. In the sensitivity analysis, according to the control source from hospital, the control source from population, the genotyping methods using PCR-RFLP, Taqman, sample size of case <100, the association of the PPARγ Pro12Ala gene polymorphism with T2DN risk was similar to those in non-sensitivity analysis. In conclusion, the PPARγ Pro/Pro genotype was associated with T2DN risk in Caucasians, but the Ala/Ala genotype and Ala allele not. However, additional studies are required to firmly establish a correlation between the PPARγ Pro12Ala gene polymorphism and T2DN risk in Caucasians.     

Association of PPARG2 Pro12Ala variant with larger body mass index in Mestizo and Amerindian populations of Mexico

Previous studies have sought to associate the Pro12Ala variant of the peroxisome proliferator-activated receptor gamma2 (PPARG2) gene with type 2 diabetes, insulin resistance, and obesity, with controversial results. We have determined the Pro12Ala variant frequency in 370 nondiabetic Mexican Mestizo subjects and in five Mexican Amerindian groups and have investigated its possible association with lipid metabolism, insulin serum levels, and obesity in three of these populations. Two independent case-control studies were conducted in 239 nondiabetic individuals: 135 case subjects (BMI > or = 25 kg/m2) and 104 control subjects (BMI < 25 kg/m2). The PPARG2 Ala12 allele frequency was higher in most Amerindian populations (0.17 in Yaquis, 0.16 in Mazahuas, 0.16 in Mayans, and 0.20 in Triquis) than in Asians, African Americans, and Caucasians. The Pro12Ala and Ala12Ala (X12Ala) genotypes were significantly associated with greater BMI in Mexican Mestizos and in two Amerindian groups. X12Ala individuals had a higher risk of overweight or obesity than noncarriers in Mestizos (OR = 3.67; 95% CI, 1.42-9.48; p = 0.007) and in Yaquis plus Mazahuas (OR = 3.21; 95% CI, 1.27-8.11; p = 0.013). Our results provide further support of the association between the PPARG2 Ala12 allele and risk of overweight or obesity in Mestizos and two Amerindian populations from Mexico.     

Alcohol intake modulates the genetic association between HDL cholesterol and the PPARgamma2 Pro12Ala polymorphism

The peroxisome proliferator-activated receptor gamma (PPARgamma) Pro12Ala polymorphism affects plasma lipids, but to what extent alcohol intake interferes with this association remains unknown. We randomly recruited 251 nuclear families (433 parents and 493 offspring) in the framework of the European Project on Genes in Hypertension study and genotyped 926 participants in whom all serum lipid variables and information on alcohol consumption were available for PPARgamma2 Pro12Ala. Genotype-phenotype relations were assessed using generalized estimating equations (GEE) and a quantitative transmission disequilibrium test (QTDT). The Ala12 allele was more frequent in Novosibirsk (0.17) than in Cracow (0.12) and Mirano (0.11) (P < 0.01). Using GEE (P = 0.03) or QTDT (P = 0.007), Italian offspring carrying the Ala12 allele had higher serum HDL cholesterol than noncarriers. HDL cholesterol levels were on average 0.086 mmol/l (P = 0.001) higher in drinkers than in nondrinkers. Compared with Pro12 homozygotes, Ala12 allele carriers consuming alcohol had higher serum total and HDL cholesterol, with the opposite trend occurring in nondrinkers. This genotype-alcohol interaction was independent of the type of alcoholic beverage and more pronounced in moderate than in heavy drinkers. We conclude that alcohol intake modulates the relation between the PPARgamma2 Pro12Ala and HDL cholesterol level and that, therefore, the Pro12Ala polymorphism, pending confirmation of our findings, might affect cardiovascular prognosis.     

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.