The peroxisome proliferator activated receptor gamma Pro12Ala polymorphism is associated with a lower hirsutism score and increased insulin sensitivity in women with polycystic ovary syndrome

Curcumin protects against lamotrigine-induced chronic ovarian and uterine toxicity in rats by regulating PPAR-γ and ROS production

Lamotrigine (LTG) is an antiepileptic drug with possible adverse effects on the female reproductive system. Curcumin was declared to improve ovarian performance. Therefore, this study aimed to clarify ovulatory dysfunction (OD) associated with LTG and the role of curcumin in ameliorating this dysfunction. Adult female Wister albino rats were assigned into four groups: negative control (received saline), positive control (received curcumin only), LTG, and LTG with curcumin groups. Drugs were administered for 90 days. The hormonal profile, including testosterone, estrogen, progesterone, luteinizing hormone, and follicle-stimulating hormone, in addition to the lipid profile and glycemic analysis, were tested. Oxidative stress biomarkers analysis in the ovaries and uterus and peroxisome proliferator-activated receptor-γ (PPAR-γ) gene expression were also included. Histopathological examination of ovarian and uterine tissues and immunohistochemical studies were also performed. Curcumin could improve the OD related to chronic LTG intake. That was proved by the normalization of the hormonal profile, glycemic control, lipidemic status, oxidative stress markers, and PPAR-γ gene expression. The histopathological and immunohistochemical examination of ovarian and uterine tissues revealed an improvement after curcumin administration. The results describe an obvious deterioration in ovarian performance with LTG through the effect on lipidemic status, PPAR-γ gene, and creating an oxidative stress condition in the ovaries of chronic users, with a prominent improvement with curcumin addition to the treatment protocol.

The Role of Peroxisome Proliferator-Activated Receptors in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) constitutes the most common endocrine disorder in women of reproductive age. Patients usually suffer from severe menstrual irregularities, skin conditions, and insulin resistance-associated health conditions. Peroxisome proliferator-activated receptors (PPARs) are nuclear receptor proteins that regulate gene expression. In order to investigate the role of PPARs in the pathophysiology of PCOS, we conducted a literature review using the MEDLINE and LIVIVO databases and were able to identify 74 relevant studies published between 2003 and 2023. Different study groups reached contradictory conclusions in terms of PPAR expression in PCOS. Interestingly, numerous natural agents were found to represent a novel, potent anti-PCOS treatment alternatives. In conclusion, PPARs seem to play a significant role in PCOS.

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].

The role of polymorphism in various potential genes on polycystic ovary syndrome susceptibility and pathogenesis

Polycystic ovary syndrome (PCOS) is the most common endocrinopathies affecting the early reproductive age in women, whose pathophysiology perplexes many researchers till today. This syndrome is classically categorized by hyperandrogenism and/or hyperandrogenemia, menstrual and ovulatory dysfunction, bulky multi follicular ovaries on Ultrasonography (USG), and metabolic abnormalities such as hyperinsulinemia, dyslipidemia, obesity. The etiopathogenesis of PCOS is not fully elucidated, but it seems that the hypothalamus-pituitary-ovarian axis, ovarian, and/or adrenal androgen secretion may contribute to developing the syndrome. Infertility and poor reproductive health in women's lives are highly associated with elevated levels of androgens. Studies with ovarian theca cells taken from PCOS women have demonstrated increased androgen production due to augmented ovarian steroidogenesis attributed to mainly altered expression of critical enzymes (Cytochrome P450 enzymes: CYP17, CYP21, CYP19, CYP11A) in the steroid hormone biosynthesis pathway. Despite the heterogeneity of PCOS, candidate gene studies are the widely used technique to delineate the genetic variants and analyze for the correlation of androgen biosynthesis pathway and those affecting the secretion or action of insulin with PCOS etiology. Linkage and association studies have predicted the relationship between genetic variants and PCOS risk among families or populations. Several genes have been proposed as playing a role in the etiopathogenesis of PCOS, and the presence of mutations and/or polymorphisms has been discovered, which suggests that PCOS has a vital heritable component. The following review summarizes the influence of polymorphisms in crucial genes of the steroidogenesis pathway leading to intraovarian hyperandrogenism which can result in PCOS.

Interaction between the dietary indices and PPAR-γ Pro12Ala gene variants on cardiovascular risk factors in patients with type 2 diabetes mellitus

AIMS

We investigated the interaction between peroxisome proliferator-activated receptor gamma (PPAR-γ) Pro12Ala polymorphism and healthy eating index (HEI), Dietary Quality Index-International (DQI-I), and dietary phytochemical index (DPI) on cardiovascular disease (CVD) risk factors in patients with type 2 diabetes mellitus (T2DM).

METHODS

This cross-sectional study was conducted on 393 diabetic patients. PPAR-γ Pro12Ala was genotyped by the PCR-RFLP method. Biochemical markers including total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG), superoxide dismutase (SOD), C-reactive protein (CRP), total antioxidant capacity (TAC), pentraxin-3 (PTX3), isoprostaneF2α (PGF2α). Interleukin 18 (IL18), leptin, and ghrelin were measured by standard protocol. Food-frequency questionnaires (FFQ) were used for dietary indices (DQI-I, DPI, HEI) calculation.

RESULTS

Homozygous carriers of the rs1801282 C allele showed higher leptin compared G allele carriers (P = .015). The rs1801282-DQI-I interactions were significant on waist circumference (WC) (P = .019). Thus, C-allele carriers in the higher tertile of DQI-I had higher WC compared with GG homozygous. Further, an interaction was observed between PPAR rs1801282 polymorphism and DQI-I on serum IL-18 level (P = .032). Besides, a significant rs1801282-DPI interaction was shown on HDL concentration (P = .041), G allele carriers who were in the highest tertile of DPI, had lower HDL. Moreover, there were significant rs1801282-HEI interactions on serum leptin (P = .021). Individuals with (CC, CG) genotypes in the higher tertile of HEI, had lower leptin concentration.

CONCLUSION

Higher dietary indices (DQI-I, DPI, HEI) may affect the relationship between PPAR-γ Pro12Ala polymorphism and WC, ghrelin, leptin, HDL, and IL-18 concentration in patients with T2DM.

Potential environmental toxicant exposure, metabolizing gene variants and risk of PCOS-A systematic review

Exposure of environmental toxicants such as potentially toxic metals and pesticides have largely been attributed to produce adverse effects on general women's health and to be more precise on the reproductive system. In order to explore exposure of toxicants and metabolizing gene variants as risk factor for polycystic ovarian syndrome (PCOS), literature search was carried out using the databases PubMed, Central Cochrane Library, Google Scholar, Science Direct with appropriate keywords upto 6 December 2020. While most of the studies indicate higher serum Cu concentration and lower concentration of Mn as risk factor, studies also report presence of higher pesticide concentration in PCOS women. Genes such as MTHFR, CYPs participate in the metabolism of toxicants and may show different response due to underlying genetic variants. Thus, toxicant exposure are to some extent responsible for the pathogenesis of syndrome through oxidative stress and endocrine disruption, but the susceptibility may vary due to the underlying genetic polymorphism of the exposed population.

Lifestyle and Food Habits Impact on Chronic Diseases: Roles of PPARs

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that exert important functions in mediating the pleiotropic effects of diverse exogenous factors such as physical exercise and food components. Particularly, PPARs act as transcription factors that control the expression of genes implicated in lipid and glucose metabolism, and cellular proliferation and differentiation. In this review, we aim to summarize the recent advancements reported on the effects of lifestyle and food habits on PPAR transcriptional activity in chronic disease.

Effects of vitamin D supplementation on follicular development, gonadotropins and sex hormone concentrations, and insulin resistance in induced polycystic ovary syndrome

Objective:

Polycystic ovary syndrome (PCOS) as a reproductive disorder disturbs ovarian follicular development, vitamin D stimulated insulin activity, and sex hormone concentrations. This study aimed to examine the effects of vitamin D on ovarian follicular development, insulin resistance, and sex hormone changes in rats with induced PCOS.

Materials and Methods:

Forty female Wistar rats were randomly divided into four groups: (1) control, (2) induced PCOS, (3) vitamin D-treated non-PCOS (sham group), (4) vitamin D treated PCOS groups. All rats were then sacrificed under anesthesia and ovarian tissue samples were evaluated histomorphometrically. Blood samples were collected for analyzing the serum concentrations of sex hormones and insulin resistance.

Results:

The number of atretic follicles at different stages of development increased in the PCOS ovaries (p<0.001). Vitamin D treatment significantly increased the normality of follicles in rats with PCOS (p<0.001). The serum concentration of follicle stimulating hormone and the estradiol significantly increased in rats with PCOS, whereas the testosterone and luteinizing hormone concentrations, glucose, insulin, and insulin resistance concentrations significantly decreased during vitamin D treatment (p<0.001).

Conclusion:

This study indicated that vitamin D treatment may protect ovarian tissue from the negative effect of PCOS by improving insulin activity and gonadotropin concentrations.

Influence of peroxisome proliferator-activated receptor-γ exon 2 and exon 6 and insulin receptor substrate (IRS)-1 Gly972Arg polymorphisms on insulin resistance and beta-cell function in southern mediterranean women with polycystic ovary syndrome

Background and objective

The Pro12Ala (exon 2) and His447His (exon 6) polymorphisms of PPAR-γ, and Gly972Arg polymorphism of IRS-1 have been implicated in insulin resistance (IR) and adiposity. Our aim was to investigate the influence of these polymorphisms on metabolic features of polycystic ovary syndrome (PCOS).

Methods

Fifty-three PCOS women and 26 control women underwent a clinical and biochemical evaluation, including a 75-g oral glucose tolerance test. Insulin secretion and insulin sensitivity indices were calculated.

Results

Frequencies of PPAR-γ polymorphisms did not differ from those predicted by the Hardy-Weinberg equilibrium. Instead, the IRS-1 Gly972Arg allele was significantly more frequent in the PCOS group compared to controls. The most frequent allelic combinations were IRS1+/exon2-/exon6- (which prevailed in PCOS) and IRS-1-/exon2-/exon6- (which prevailed in controls). Among PCOS women, compared with the wild type patients, carriers of the Gly972Arg IRS-1 allele had lower E2 levels, while carriers of the Pro12Ala PPAR-γ (exon 2) allele had lower free testosterone levels. No other significant relationships were noted. When compared with the wild type, in PCOS group IR and beta-cell function were: (i) trendwise greater in carriers of the variant IRS-1 allele; (ii) trendwise lower in carriers of the variant PPAR-γ exon 6 allele; (iii) significantly lower in carriers of the variant PPAR-γ exon 2 allele.

Conclusions

Our data support the protective influence of PPAR-γ-exon 2 and exon 6 variants on IR and beta cell function, whereas IRS-1 polymorphism is associated with an unfavorable metabolic profile. However, these associations do not fully explain the high metabolic risk associated with PCOS.

The Association of PPARγ Pro12Ala and C161T Polymorphisms with Polycystic Ovary Syndrome and Their Influence on Lipid and Lipoprotein Profiles

Background

The aim of present study was to clarify the role of the peroxisome proliferator-activated receptor (PPAR) γ Pro12Ala and C161T polymorphisms in the pathogenesis of polycystic ovary syndrome (PCOS) and their influence on lipid and lipoprotein profiles of patients.

Materials and Methods

The present cross-sectional study consisted of 50 women with PCOS, who referred to the Kermanshah University of Medical Sciences Clinic between April and October 2015, and 233 unrelated age-matched healthy women from the same region (West Iran). The PPARγ Pro12Ala and PPARγ C161T polymorphisms were gen- otyped using the polymerase chain reaction-restriction fragment length polymorphism method. Fasting blood sugar (FBS), serum triglycerides (TG), cholesterol, low density lipoprotein- cholesterol (LDL-C), high density lipoprotein- cholesterol (HDL-C) and estradiol levels were measured.

Results

The serum level of estradiol was significantly lower in PCOS patients compared to healthy women. The PPARγ Pro12Ala (CG) genotype increased the risk of PCOS 2.96-fold. The frequency of the PPARγ T allele (at C161T) was 21% in patients and 17.2% in controls with no significant difference (P=0.52). In all studied individuals, the PPARγ CG geno- type was associated with significantly higher levels of TG. However, significantly lower levels of total cholesterol and LDL-C were observed in PPARγ TT individuals compared with those with the CC genotype. Within the PCOS group, the PPARγ CG genotype was significantly associated with lower levels of estradiol compared with the CC genotype. Also, the CG genotype was significantly associated with higher levels of TG when compared with the CC genotype.

Conclusion

Our study shows that, unlike PPARγ C161T, PPARγ Pro12Ala is associated with the risk of PCOS. Also, we found that the lipid and lipoprotein profiles significantly vary based on PPARγ Pro12Ala and C161T genotypes.

PPARγ Pro12Ala and C161T polymorphisms in patients with acne vulgaris: Contribution to lipid and lipoprotein profile

PURPOSE

The aim of present study was to clarify the role of peroxisome proliferator-activated receptor γ (PPARγ) Pro12Ala and C161T variants in the pathogenesis of acne vulgaris (AV) and their influence on lipid and lipoprotein profile.

METHODS

The present case-control study consisted of 393 individuals including 198 patients with AV (mild-, moderate-, and severe-AV) and 195 unrelated age-matched healthy individuals from Western Iran. The PPARγ Pro12Ala and C161T polymorphisms were identified using polymerase chain reaction-restriction length polymorphism method. Also, serum lipid and lipoprotein profile and fasting blood sugar (FBS) were detected in studied individuals.

RESULTS

In women patients with AV significantly higher serum levels of FBS, total cholesterol, low density lipoprotein-cholesterol (LDL-C) and high density lipoprotein-cholesterol compared to healthy women were detected. Neither PPARγ Pro12Ala nor C161T polymorphism was associated with the risk of AV but the Pro allele was a risk factor for AV among all men and women patients ≥20years. The variant genotype of PPARγ CG (Pro/Ala) was associated with significantly higher levels of total cholesterol and triglycerides compared to CC (Pro/Pro) genotype. We detected a significantly lower level of FBS in the presence of CT+TT genotype of PPARγ C161T compared to CC genotype. Also, carriers of PPARγ TT genotype had significantly lower serum level of total cholesterol and LDL-C compared to CC genotype.

CONCLUSIONS

Our results demonstrated the association of PPARγ Pro allele with susceptibility to AV in patients ≥20years and the influence of PPARγ Pro12Ala and C161T polymorphisms on the lipid and lipoprotein profile.

Interaction between peroxisome proliferator-activated receptor gamma polymorphism and obesity on type 2 diabetes in a Chinese Han population

AIMS

The aim of this study was to investigate the association of four single nucleotide polymorphisms (SNPs) of peroxisome proliferator-activated receptor gamma (PPARG) with type 2 diabetes mellitus (T2DM) risk and additional role of gene-obesity interaction.

METHODS

Four SNPs were selected for genotyping in the case-control study: rs1805192, rs709158, rs3856806 and rs4684847. Generalized multifactor dimensionality reduction (GMDR) model and logistic regression was used to examine the interaction between SNP and obesity on T2DM, odds ratio (OR) and 95% confident interval (95% CI) were calculated.

RESULTS

T2DM risk was significantly higher in individuals with rs1805192-G allele (p < 0.05). The carriers of G allele of the rs1805192 polymorphism revealed increased T2DM risk than those with CC variants (CG + GG versus CC, adjusted OR (95% CI) 1.76 (1.45-2.06), p < 0.001). T2DM risk was also significantly higher in individuals with rs3856806-T allele (p < 0.05). The carriers of T allele of the rs3856806 polymorphism revealed increased T2DM risk than those with CC variants (CT + TT versus CC, adjusted OR (95% CI) 1.25 (1.17-1.76), p < 0.001). There was a significant two-locus model (p = 0.0107) involving rs1805192 and obesity. Obese subjects with CG or GG genotype have the highest T2DM risk, compared to subjects with CC genotype and normal BMI (OR 2.40, 95% CI 1.68-3.63).

CONCLUSIONS

Our results support an important association between rs1805192 and rs3856806 minor allele (G allele) of PPARG and increased T2DM risk, the interaction analysis shown a combined effect of G- obesity interaction between rs1805192 and obesity on increased T2DM risk.

Association between single nucleotide polymorphisms of sterol regulatory element binding protein-2 and liver X receptor α gene and risk of polycystic ovary syndrome in a Chinese Han population

To investigate associations of single nucleotide polymorphisms (SNPs) rs2228314 of sterol regulatory element-binding protein-2 (SREBP-2) or rs11039155 of liver X receptor α (LXRα) with susceptibility to polycystic ovary syndrome (PCOS) in a Chinese Han population. SREBP-2 rs2228314 and LXRα rs11039155 polymorphisms were genotyped in patients with PCOS and age- and sex-matched PCOS-free controls from a Chinese Han population. A total of 605 patients with PCOS and 615 controls were recruited in this study. We found that GC and CC genotypes of rs2228314, and variant C, were associated with a significantly increased risk of PCOS. In addition, GA and AA genotypes of rs11039155, as well as variant A, were also associated with a significantly increased risk of PCOS. Our results showed that SREBP-2 rs2228314 G to C change and variant C genotype as well as LXRα rs11039155 G to A change and variant A may contribute to PCOS in Chinese Han population.

Association of PPARG Pro12Ala polymorphism with insulin sensitivity and body mass index in patients with polycystic ovary syndrome

Insulin resistance is one of the key factors in the pathogenesis of polycystic ovary syndrome (PCOS). The peroxisome proliferator-activated receptor gamma (PPARG) plays a role in the regulation of insulin sensitivity. The aim of the present study was to establish a possible association of the PPARG Pro12Ala polymorphism with PCOS and its effect on family and personal history, as well as on the metabolic and endocrine parameters in PCOS patients. A total of 151 PCOS patients and 179 healthy women of reproductive age were enrolled. History, body mass index (BMI), waist-to-hip ratio and the presence of phenotypic hyperandrogenism were recorded. Hormonal, metabolic and biochemical profiles were assessed. A molecular analysis for the genetic polymorphism was performed. One third (29.8%) of the PCOS patients were found to be carriers of at least one variant of the Ala allele (X/Ala), while 70.2% carried two wild-type Pro alleles (Pro/Pro), with an equal distribution observed in the control group. The PCOS patients carrying the X/Ala alleles exhibited lower serum fasting insulin levels, homeostatic model assessment of insulin resistance (HOMA-IR) and BMI compared to Pro/Pro carriers. This finding was significant only in the lean PCOS group. The polymorphic genotype exerted no effect on history, hormonal and clinical hyperandrogenism, lipid status or C-reactive protein, leptin, adiponectin, resistin and ghrelin serum levels in women with PCOS. In conclusion, although the PPARG Pro12Ala polymorphism is not a major determinant of PCOS in the Croatian population, it may exert a positive effect on insulin sensitivity and BMI. As these associations were recorded exclusively in the lean group of patients with PCOS, this polymorphism potentially contributes to a protective role against hyperinsulinemia and obesity.

Genetic variants associated with insulin signaling and glucose homeostasis in the pathogenesis of insulin resistance in polycystic ovary syndrome: a systematic review

BACKGROUND

Polycystic ovary syndrome must be recognized as a serious issue due to its implication on long term health regardless of an individual's age. PCOS and insulin resistance are interlinked, as approximately 40 % of women with PCOS are insulin resistant. However, the detailed molecular basis for insulin resistance that is coupled with PCOS remains poorly understood.

OBJECTIVE

To review the published evidence that polymorphisms in genes that are involved in insulin secretion and action are associated with an increased risk of PCOS.

METHODS

We reviewed articles published through November 2012 which concerned polymorphisms of genes related to insulin signaling and glucose homeostasis as well as their associations with PCOS. The articles were identified via Medline searches.

CONCLUSIONS

No consistent evidence emerged of a strong association between the risk of PCOS and any known gene that is related to insulin signaling and glucose homeostasis. Moreover, recent genome-wide association studies are inconsistent in identifying the associations between PCOS and insulin metabolism genes. Many of the studies reviewed were limited by heterogeneity in the PCOS diagnosis and by not have having a sufficient number of study participants. Further studies are warranted to determine predisposing risk factors which could modify environmental factors and thus reduce the risk of PCOS. Large genome-wide association studies devoted solely to PCOS will be necessary to identify new candidate genes and proteins that are involved in PCOS risk.

Peroxisome proliferator activated receptor gamma gene variants influence susceptibility and insulin related traits in Indian women with polycystic ovary syndrome

PURPOSE

Peroxisome proliferator activated receptor gamma (PPARγ), a transcription factor involved in glucose and lipid metabolism is one of the candidate genes associated with polycystic ovary syndrome (PCOS). We investigated individual and combined associations of Pro12Ala and His447His polymorphisms of PPARγ with PCOS susceptibility and its related traits (hyperinsulinemia, hyperandrogenemia and lipid parameters) in Indian women.

METHOD

Genotyping of PPARγ polymorphisms in this case-control study was performed in PCOS (n = 450) and age-matched controls (n = 300) by direct sequencing. Clinical, anthropometric, hormonal and metabolic parameters were estimated in 275 women with PCOS and 169 controls. Chi-square test was used to compare the categorical data while regression analysis was used to evaluate association of genotypes with PCOS as well as its related phenotypes.

RESULTS

The frequencies of CC and CG + GG genotypes of Pro12Ala (χ² = 15.3, p < 0.0001) and CC and CT + TT genotypes of His447His (χ² = 12.7, p = 0.0004) polymorphisms were significantly different between PCOS and controls. Logistic regression analysis revealed a significant association of PCOS with Pro12Ala but not the His447His polymorphism. Carriers of variant genotypes at both PPARγ loci showed significantly reduced 2 h glucose levels while carriers of variant His447His genotype showed lower fasting insulin and HOMA-IR levels in PCOS women.

CONCLUSIONS

Pro12Ala polymorphism of PPARγ showed significant association with decreased PCOS susceptibility. Both polymorphisms influenced insulin related traits (2 h glucose, fasting insulin and HOMA-IR) and improved glucose metabolism in these women. This is the first report to establish that variations in PPARγ gene influence the insulin resistance pathophysiology in Indian women with PCOS.

Genetic variants in central metabolic genes influence some but not all relations of inflammatory markers in a collective with polycystic ovary syndrome

Patients with polycystic ovary syndrome (PCOS) suffer, in addition to reproductive disturbances, from symptoms of the metabolic syndrome like insulin resistance, elevated coronary risk and visceral obesity. Genes with confirmed associations to the metabolic syndrome are also candidate genes for a relationship to metabolic parameters of the PCOS syndrome. The study presented indicates that genetic variants of the transcription factors LXRα or PPARγ and the PON-1 or the IGF-2 cluster are associated with altered metabolic phenotypes in PCOS patients. Next to this the absolute cytokine levels and the relation of certain cytokines to IL2, IL12 or INFγ are depending on the genotype. These observations support the hypothesis that various genetic variants in metabolic relevant genes might not only alter the metabolic characteristics within a cohort of PCOS patients but might also influence the cytokine level and the overall pattern of secreted cytokines.

Common variants of transcription factor 7-like 2 (TCF7L2) are associated with reduced insulin secretion in women with polycystic ovary syndrome

Common variants of the transcription factor 7-like 2 (TCF7L2) gene were identified as one of the few genetic polymorphisms with powerful effects on the risk of type 2 diabetes (T2D). Given the genetic overlap between polycystic ovary syndrome (PCOS) and T2D, the present study was undertaken to investigate whether the TCF7L2 variants are also associated with PCOS. We analyzed single nucleotide polymorphisms (SNPs) rs11196218 and rs290487 of the TCF7L2 gene, which showed robust associations with T2D in Chinese population, in 430 PCOS patients and 360 control subjects by pyrosequencing, and also assessed the effect of genotype on clinical and biochemical traits in the PCOS group. We found no evidence for association between SNP rs11196218 and PCOS. The SNP rs290487 showed marginal differences in genotype frequencies between the PCOS and control group, with the minor C allele being the at-risk allele for PCOS. In PCOS women, the C allele carriers of rs290487 had higher levels of 2h blood glucose but lower insulinogenic index than noncarriers, suggesting impaired insulin secretion. Our data suggested that the TCF7L2 variants may confer an increased risk for early impairment of glucose homeostasis in PCOS.

A meta-analysis on the association between PPAR-γ Pro12Ala polymorphism and polycystic ovary syndrome

PURPOSE

To investigate the influence of the peroxisome proliferator activated receptor gamma (PPAR-γ) Pro12Ala polymorphism on the susceptibility of polycystic ovary syndrome (PCOS) and body mass index (BMI), fast insulin levels, homeostasis model assessment of insulin resistance (HOMA-IR) in PCOS patients.

METHODS

PubMed, EMBASE, MEDLINE and CENTRAL databases were searched to identify eligible studies. We then conducted a meta-analysis to examine the association between Pro12Ala polymorphism and PCOS.

RESULTS

Seventeen eligible studies, including 2,149 patients and 2,124 controls were enrolled in this meta-analysis. Pro12Ala polymorphism was significantly associated with the susceptibility of PCOS (odds ratio [OR] 0.74, 95 % confidence interval [CI] [0.61, 0.90] for allele; OR 0.70, 95 % CI [0.57, 0.86] for genotype). In the European subgroup of PCOS, the X/Ala genotype was associated with lower BMI (mean difference [MD] -1.08, 95 % CI [-2.08, -0.09]) and fast insulin levels (MD -19.82, 95 % CI [-34.07, -5.58]). However, this polymorphism did not display an impact on HOMA-IR in PCOS patients.

CONCLUSIONS

Ala variant would decrease the risk of PCOS and result in lower BMI and fast insulin levels in a European population, but had no impact on HOMA-IR in PCOS patients. Further studies are required to elucidate these associations more clear.

Pro12Ala PPAR γ2 gene polymorphism in PCOS women: the role of compounds regulating satiety

Five to ten percent of women of reproductive age suffer from polycystic ovary syndrome (PCOS). Leptin, NPY, galanin, cholecystokinin (CCK) are involved in the regulation of eating behavior. PPARγ are receptors that are probably involved in hyperandrogenism. This study was designed to assess associations between the Pro12Ala PPARγ2 gene polymorphism and satiety factors in PCOS. Fifty-four PCOS women and 51 healthy women were studied. Leptin, NPY, galanin, CCK levels, and genetic studies to detect Pro12Ala PPARγ2 gene polymorphism were assessed. The leptin levels in the PCOS women carrying Pro12Ala genotype were higher than in those with Pro12Pro and Ala12Ala. The PCOS women had higher leptin and NPY levels and lower galanin levels. Obese PCOS patients had lower CCK levels.

CONCLUSIONS

In the PCOS women, a single Ala allele may have a protective role as far as hyperleptinemia is concerned. The PCOS women may reveal a disrupted central leptin/NPY feedback loop with some shifts in food intake.

Understanding polycystic ovarian syndrome pathogenesis: an updated of its genetic aspects

Polycystic ovary syndrome (PCOS) is the most frequent cause of female infertility. It is also characterized by metabolic defects that raise the risk for cardiovascular disease. Despite the progress in the definition of the clinical aspects of the syndrome, only very few definite data are available about the ethiopathogenetic mechanisms that subtend PCOS. It is likely that the PCOS phenotype derives from the interaction between environmental and genetic factors. While environmental factors have easily been investigated, the individuation of the genetic factors seem to be more complex. Indeed, PCOS appears to be inherited as a complex, polygenic trait. Several family studies have been conducted with the aim to clarify the genetic aspects of PCOS, but their findings are often conflicting and not conclusive.Moreover, it is difficult to establish with certainty which genes are involved and their effective role in the development of the syndrome because in PCOS, genetic analysis is hampered by low fecundity, lack of a male phenotype, absence of an animal model, and dissimilarity of the diagnostic criteria used to select the patients. Since multiple biochemical pathways are implicated in PCOS pathogenesis, genes of steroid hormone metabolism, gonadotropin release and action, insulin secretion and action, adipose tissue metabolism and others have been investigated. Nevertheless, none of them seems to play a key role in the ethiopathogenesis of PCOS. This article reviews the large body of literature generated to support the presence of genetic abnormalities in PCOS women by taking in consideration the most important studies regarding PCOS candidate genes.

The Genetic Basis of the Polycystic Ovary Syndrome: A Literature Review Including Discussion of PPAR-gamma

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder of the women of reproductive age. Familial clustering of PCOS has been consistently reported suggesting that genetic factors play a role in the development of the syndrome although PCOS cases do not exhibit a clear pattern of Mendelian inheritance. It is now well established that PCOS represents a complex trait similar to type-2 diabetes and obesity, and that both inherited and environmental factors contribute to the PCOS pathogenesis. A large number of functional candidate genes have been tested for association or linkage with PCOS phenotypes with more negative than positive findings. Lack of universally accepted diagnostic criteria, difficulties in the assignment of male phenotype, obscurity in the mode of inheritance, and particularly small sample size of the study populations appear to be major limitations for the genetic studies of PCOS. In the near future, utilizing the genome-wide scan approach and the HapMap project will provide a stronger potential for the genetic analysis of the syndrome.

PPAR Gamma: Coordinating Metabolic and Immune Contributions to Female Fertility

Peroxisome proliferator-activated receptor gamma (PPARG) regulates cellular functions such as adipogenesis and immune cell activation. However, new information has indicated additional roles of PPARG directing the cyclic changes that occur within ovarian tissue of female mammals, including those that facilitate the release of oocytes each estrous cycle. In addition to ovarian PPARG expression and function, many PPARG actions within adipocytes and macrophages have additional direct and indirect implications for ovarian function and female fertility. This encompasses the regulation of lipid uptake and transport, insulin sensitivity, glucose metabolism, and the regulation of inflammatory mediator synthesis and release. This review discusses the developing links between PPARG activity and female reproductive function, and highlights several mechanisms that may facilitate such a relationship.

A functional GNAQ promoter haplotype is associated with altered Gq expression and with insulin resistance and obesity in women with polycystic ovary syndrome

OBJECTIVES

The G-protein Gq, encoded by GNAQ, is involved in glucose metabolism. The GNAQ promoter harbours three polymorphisms. The TT(-695/-694)GC polymorphism was already shown to affect Gq transcription. Accordingly, we (i) characterized the GNAQ promoter polymorphisms G(-173)A and G(-168)A, (ii) investigated potential influences upon the TT(-695/-694)GC polymorphism and (iii) studied the associations with metabolic abnormalities in polycystic ovary syndrome (PCOS).

METHODS

Characterization of the polymorphisms was performed with electrophoretic mobility shift assays and reporter assays. Inhibition of lipolysis and Gq expression were measured in adipocytes isolated from female mammary tissue. We genotyped 266 healthy Caucasians, 265 women with PCOS, and 293 healthy, age-matched female controls to associate GNAQ promoter polymorphisms and haplotypes with anthropometric and metabolic variables.

RESULTS

The A(-168) allele was associated with significantly decreased transcriptional activity and altered transcription factor binding, whereas the G(-173)A polymorphism appeared functionally silent. Linkage and haplotype frequencies analysis resulted in four common haplotypes. In adipose tissue, a 44% higher Gq mRNA concentration was observed in homozygous GC(-695/-694)-G(-168) haplotypes compared with homozygous TT(-695/-694)-G(-168) haplotypes (P=0.046). This was associated with increased insulin inhibition of lipolysis in isolated adipocytes. In PCOS patients, the homozygous GC-G haplotype was associated with decreased insulin resistance and body mass index (BMI) compared with the homozygous TT-G haplotype (homeostatic model assessment of insulin resistance: 3.4+/-0.4 vs. 5.6+/-0.7 mmol/l x mmol/l2, P=0.001; fasting insulin: 86.6+/-11.9 vs. 128.8+/-16.5 pmol/l, P=0.003; BMI: 29.3+/-1.2 vs. 33.9+/-1.3 kg/m2, P=0.002). No association with BMI was found in healthy women.

CONCLUSION

G(-168)A is functionally relevant and in linkage with TT(-695/-694)GC. GNAQ promoter diplotypes are associated with insulin resistance and obesity in PCOS.

Association between peroxisome proliferator-activated receptor-γ gene polymorphism (Pro12Ala) and Helicobacter pylori infection in gastric carcinogenesis

OBJECTIVE

Helicobacter pylori infection is accompanied by inflammatory processes leading to peptic ulcer and gastric cancer in the minority of infected individuals. The interaction between H. pylori virulence factors, host defense mechanisms and environmental factors determine the outcome of clinical manifestations. One of the host factors involved in the processes of inflammation and carcinogenesis is the peroxisome proliferator-activated receptor-γ (PPAR-γ) molecule. The present case-control study aimed to determine polymorphism of PPAR-γ gene and its association with H. pylori infection and gastrointestinal diseases (peptic ulcer and non-cardia gastric cancer) in Iranian patients.

MATERIALS AND METHODS

One hundred and fifty-five patients with upper gastrointestinal diseases (76 peptic ulcer and 79 non-cardia gastric cancer) and 152 matched controls were genotyped for PPAR-γ gene polymorphism (Pro12Ala) by the PCR-RFLP method. Infection with H. pylori was confirmed by histology, the rapid urease test (RUT) and ELISA assay (IgG anti-H. pylori).

RESULTS

The frequency of PPAR-γ G (Ala 12) allele was significantly higher in H. pylori positive patients with non-cardia gastric cancer than in controls (22.8% vs. 3.9%, p = 0.027; OR = 3.28; 95% CI = 1.21-8.89), But there was no significant difference without infection (p = 0.7). Moreover, the PPAR-γ polymorphism was not associated with peptic ulcer in the presence or absence of H. pylori infection.

CONCLUSION

Our results indicated PPAR-γ G allele may be an important contributor to non-cardia gastric cancer in Iranian H. pylori infected patients.

The role of genetic variation in peroxisome proliferator-activated receptors in the polycystic ovary syndrome (PCOS): an original case-control study followed by systematic review and meta-analysis of existing evidence

OBJECTIVE

To study the association of polymorphisms in the genes encoding peroxisome proliferator-activated receptors (PPARs) with the polycystic ovary syndrome (PCOS).

DESIGN

Case-control study and meta-analysis of published evidence.

PATIENTS

One hundred and sixty-one polycystic ovary syndrome patients and 113 non-hyperandrogenic women.

MEASUREMENTS

Genotyping for PPAR-gamma coactivator-1 gene (PPARGC1A) Gly482Ser, PPAR-alpha Leu162Val, PPAR-delta rs2267668A/G, PPAR-delta-87T/C, PPAR-gamma2 Pro12Ala and PPAR-gamma2 -681C/G variants and systematic review of the literature using the Entrez-PubMed search engine, followed by meta-analysis whenever possible.

RESULTS

Polycystic ovary syndrome patients carried the Gly482Ser variant in PPARGC1A more frequently than controls (72%vs. 58%, chi(2 )=( )5.54 P = 0.019), whereas carriers of the PPAR-alpha Leu162Val, PPAR-delta rs2267668A/G, PPAR-delta-87T/C, PPAR-gamma2 Pro12Ala and PPAR-gamma2 -681C/G variants were distributed similarly among both groups. The interaction between the PPARGC1A Gly482Ser and PPAR-delta-87T/C variants was also associated with PCOS (OR = 1.24, 95% CI 1.05-1.50, P = 0.008). The systematic review identified 31 studies addressing associations between PPARs variants and PCOS; meta-analysis was possible for nine studies focusing on the PPAR-gamma2 Pro12Ala variant. Although the individual studies did not reveal any statistically significant association, meta-analysis uncovered that carrying the PPAR-gamma2 Pro12Ala variant was associated with a reduced probability of having PCOS (OR = 0.77, 95% CI 0.61-0.96, P = 0.025), and that this association may be mediated by an effect on insulin sensitivity.

CONCLUSIONS

Common polymorphisms in the PPARGC1A, PPAR-delta and PPAR-gamma2 loci are associated with PCOS.

The Pro12Ala polymorphism of the PPAR-gamma gene is not associated with the polycystic ovary syndrome

OBJECTIVE

Insulin resistance is a key factor in the pathogenesis of polycystic ovary syndrome (PCOS). Peroxisome proliferator-activated- receptor-gamma (PPAR-gamma) has been implicated in insulin resistance and adiposity. The aim of the study was to investigate the possible involvement of the Pro12Ala polymorphism of the PPAR-gamma gene in the pathogenesis of PCOS.

DESIGN

We studied 180 women with PCOS and 140 healthy controls. Body mass index (BMI) was recorded. Blood samples were drawn after overnight fasting and serum glucose, insulin, lipid and hormonal profiles were determined. The fasting glucose/insulin ratio and HOMA index were calculated. Moreover, 100 women with PCOS underwent a 75g oral glucose tolerance test and the area under the curve for insulin and glucose was estimated. DNA was extracted from peripheral blood leucocytes and the Pro12Ala polymorphism was genotyped.

RESULTS

The PPAR-gamma genotypes were found to be in the Hardy-Weinberg equilibrium in both study groups. No difference was found in the distribution of the Pro12Ala polymorphism between PCOS and controls. Insulin resistance indices and lipid and hormonal profile were not different among the various genotypes of the Pro12Ala polymorphism.

CONCLUSIONS

The Pro12Ala polymorphism of the PPAR-gamma gene is not involved in the pathogenesis or the phenotypic expression of PCOS.

Pro12Ala and His447His polymorphisms of PPAR-gamma are associated with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects 4-12% of women of reproductive age, and is specified when two of the three following criteria are present: hyperandrogenism, oligomenorrhoea and polycystic ovary morphology by ultrasonography. PCOS is characterized by infertility, obesity and hyperinsulinaemia. However, the aetiology of PCOS has not yet been fully identified due to complex metabolic mechanisms. Many researchers have demonstrated that polymorphisms of putative genes related to symptoms are associated with PCOS. In the reproductive system, energy metabolism and hormonal regulation are important to differentiate granulosa cells in the ovary. Peroxisome proliferator-activated receptor gamma (PPAR-gamma) is a transcription factor, and is known to be associated with insulin sensitivity. Furthermore, it is highly expressed in granulosa cells. It was recently reported that various polymorphisms of PPAR-gamma are associated with PCOS in different ethnic backgrounds. This study has shown that both Pro12Ala and His447His polymorphisms of PPAR-gamma are associated with PCOS in a Korean population.

The role of genetic variation in the lamin a/c gene in the etiology of polycystic ovary syndrome

OBJECTIVE

We performed this study to test the hypothesis that variation in the lamin a/c gene (LMNA) contributes to milder phenotypes of insulin resistance, hyperandrogenism, and/or metabolic syndrome associated with polycystic ovary syndrome (PCOS).

RESEARCH DESIGN AND METHODS

We resequenced the coding region, flanking intronic, and proximal promoter regions of the lamin a/c gene in 43 women with PCOS with evidence of upper-body obesity (waist circumference >88 cm) and identified 56 variants, two of which were nonsynonymous substitutions (lmna11 exon1 E98D; lmna24 exon 7 R455C). We genotyped 53 single-nucleotide polymorphisms (44 identified through resequencing and nine included to maximize informativeness of the entire gene) in 624 index (PCOS) cases and 544 controls of European ancestry. We tested for association between these variants and PCOS. In a subset of individuals, we also tested for association with metabolic syndrome and quantitative traits (body mass index, waist circumference, total testosterone, dehydroepiandrosterone sulfate, fasting glucose and insulin, low-density lipoprotein, and total triglycerides).

RESULTS

After correction for multiple testing, none of the variants showed significant evidence for association with PCOS, the metabolic syndrome, or any of the quantitative traits tested.

CONCLUSIONS

Whereas these studies cannot exclude the role of genetic variation in the lamin a/c gene in isolated cases of PCOS, we can conclude that common variation in the lamin a/c gene does not contribute to the etiology of PCOS in women of European ancestry.

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.

Functional genetic polymorphisms and female reproductive disorders: Part I: Polycystic ovary syndrome and ovarian response

BACKGROUND

The identification of polymorphisms associated with a disease can help to elucidate its pathogenesis, and this knowledge can be used to improve prognosis for women with a particular disorder, such as polycystic ovary syndrome (PCOS). Since an altered response to ovarian stimulation is also a characteristic of the disease, further knowledge about its aetiology could help in defining the parameters that determine the response of an individual to ovarian stimulation.

METHODS

PubMed and EMBASE databases were systematically searched for gene association studies published until the end of August 2007, using search criteria relevant to PCOS and ovarian response to stimulation. Data from additional papers identified through hand searches were also included; 139 publications were reviewed.

RESULTS

Several genes involved in ovarian function and metabolism are associated with increased susceptibility to PCOS, but none is strong enough to correlate alone with susceptibility to the disease, or response to therapy. A single-nucleotide polymorphism in exon 10 of the FSH receptor (FSHR) gene, FSHR p.N680S, was consistently identified as having a significant association with ovarian response to FSH.

CONCLUSIONS

No consistent association between gene polymorphism and PCOS could be identified. The FSHR gene may play a significant role in the success of ovarian stimulation, and can be used as a marker to predict differences in FSHR function and ovarian response to FSH. Genotyping the FSHR p.N680S polymorphism may provide a means of identifying a population of poor responders before in vitro fertilization procedures are initiated.

Peroxisome proliferator-activated receptors: new players in the field of reproduction

Peroxisome proliferator-activated receptors (PPAR) are members of the nuclear hormone receptor superfamily. Synthetic ligands to one family member, PPARgamma, are currently widely used as treatment for chronic diseases such as diabetes type II and other insulin resistances, e.g. as seen in polycystic ovary syndrome (PCOS). Moreover, novel approaches employing knock-out mice demonstrated that PPARgamma seems to play a key role in placental and fetal development. This review describes recent insights into the role of PPARs in human reproduction with specific reference to infertility, placental maturation and fetal development as well as disturbed pregnancy. Further, we highlight the current knowledge on synthetic ligands to PPARgamma used as a treatment in women with PCOS.

Functional ovarian hyperandrogenism and polycystic ovary syndrome in prepubertal girls with obesity and/or premature pubarche

AIMS

Functional ovarian hyperandrogenism (FOH) is considered to be a form of polycystic ovary syndrome (PCOS) at adolescence. There are almost no data in the prepubertal period, although one of the earliest manifestations of PCOS is premature pubarche. Prepubertal girls with obesity or insulin resistance are also at risk to develop the full PCOS phenotype after puberty. The aim of this study was to evaluate prepubertal girls with premature pubarche and/or obesity for PCOS or FOH.

METHODS

Twenty-seven prepubertal girls with premature pubarche and/or obesity aged >6 years were evaluated. FOH was defined as abnormal ovarian 17OHP response to challenge with GnRH analog of >2 ng/ml after exclusion of adrenal dysfunction. All patients underwent a pelvic ultrasound examination.

RESULTS

Sixteen patients had premature pubarche, seven were obese, and four had both premature pubarche and obesity. Eleven of 27 patients (40.7%) showed high (>2 ng/ml) 17OHP response to GnRH challenge. Three patients (11%) with FOH also showed PCO morphology on pelvic ultrasound examination.

CONCLUSION

In prepubertal girls who carry risk factors, including genetic polymorphisms and/or particular environmental factors, FOH/PCOS could develop at a high rate.

Genetic variants in peroxisome proliferator-activated receptor gamma influence insulin resistance and testosterone levels in normal women, but not those with polycystic ovary syndrome

OBJECTIVE

To investigate the relationship of the peroxisome proliferator-activated receptor gamma (PPARG) Pro12Ala and silent exon 6 (His447His) polymorphisms with the clinical features of polycystic ovary syndrome (PCOS).

DESIGN

Patients with PCOS and control subjects were genotyped for Pro12Ala and His447His. Associations between genotype, diagnosis, and hormonal/metabolic parameters were assessed.

SETTING

Subjects were recruited from the reproductive endocrinology clinic at the University of Alabama at Birmingham, Birmingham, Alabama. Control subjects were recruited from the surrounding community. Genotyping was performed at the Cedars-Sinai Medical Center in Los Angeles, California.

PATIENT(S)

Participants included 285 white women with PCOS and 187 controls.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The Pro12Ala and His447His genotypes, and hormonal and metabolic phenotypes.

RESULT(S)

The Pro12Ala and His447His genotypes did not influence risk of PCOS or its component phenotypes in patients with PCOS. In controls, Pro12Ala did not influence measures of insulin resistance or androgen production. However, carriers of the His447His T-allele had significantly decreased free and total T levels, and a significantly decreased homeostasis model assessment index of insulin resistance. Furthermore, haplotypes in controls bearing the His447His T-allele were also associated with decreased T.

CONCLUSION(S)

Peroxisome proliferator-activated receptor gamma does not appear to be an important modifier gene in PCOS. In controls, however, the His447His T-allele may be in linkage disequilibrium with a functional variant that influences insulin resistance and T production.

Obesity and polycystic ovary syndrome

The aetiology of Polycystic Ovary Syndrome (PCOS) is complex and multifactorial. There is much evidence, however, to suggest that adipose tissue plays an important role in the development and maintenance of PCOS pathology. There is a close correlation between adiposity and symptom severity in women with PCOS, and even modest reductions in weight generally translate into significant improvements in menstrual regularity, fertility and hyperandrogenic features. This review article considers the various mechanisms that might underlie this link between excess adiposity and PCOS - including the effects of differential insulin sensitivity, abnormal steroid hormone metabolism and adipocytokine secretion. Greater attention to the therapeutic options available to reduce the impact of excess adiposity on ovarian and metabolic function is essential to the management of PCOS.

Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-gamma gene in women with polycystic ovary syndrome

AIM

The present study was designed to examine the relationship between Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-gamma gene (PPAR-gamma) and clinical and hormonal characteristics in women with polycystic ovary syndrome (PCOS).

MATERIALS AND METHODS

One hundred patients with PCOS and 100 healthy subjects were included in the study. Serum levels of sex steroids were measured. Insulin resistance was evaluated by homeostasis model assessment (HOMA). The responses of glucose and insulin to an oral glucose tolerance test were analyzed by calculating the respective area under the curve (AUC) by the trapezoidal method. We used the restriction fragment length polymorphism technique and polymerase chain reaction to examine Pro12Ala polymorphism in exon 2 of PPAR-gamma.

RESULTS

Pro12Ala polymorphism of PPAR-gamma was significantly elevated in control subjects (22%) compared with PCOS subjects (15%). All of the Pro12Ala polymorphisms of PPAR-gamma were heterozygous. When PCOS subjects with the Pro allele and the Ala allele of PPAR-gamma were compared, the latter had lower free testosterone, androstenedione, dehydroepiandrosterone sulfate, insulin and C-peptide levels, as well as lower luteinizing hormone/follicle-stimulating hormone ratio, HOMA insulin resistance index, AUCinsulin, Ferriman-Gallwey score, acne, body mass index and waist-to-hip ratio.

CONCLUSION

We suggest that Pro12Ala polymorphism of the PPAR-gamma gene may be a modifier of insulin resistance in women with PCOS.

Polymorphisms of the peroxisome proliferator–activated receptor-γ and its coactivator-1α genes in Chinese women with polycystic ovary syndrome

The polymorphisms of the peroxisome proliferator-activated receptor-gamma (Pro12Ala) and its coactivator-1 (Gly482Ser) genes were investigated among 201 Chinese Han women with polycystic ovary syndrome (PCOS) and among 147 regularly cycling women as control subjects. We did not find statistically significant differences with peroxisome proliferator-activated receptor-gamma2 Pro12Ala and peroxisome proliferator-activated receptor-gamma-1alpha Gly482Ser polymorphism distributions between Chinese women with PCOS and controls, or with body mass index and reproductive hormones among various genotypic groups of PCOS, suggesting that these genetic mutants did not have an effect on the susceptibility to PCOS.

The human obesity gene map: the 2005 update

This paper presents the 12th update of the human obesity gene map, which incorporates published results up to the end of October 2005. 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 (QTL) from animal cross-breeding experiments, association studies with candidate genes, and linkages from genome scans is reviewed. As of October 2005, 176 human obesity cases due to single-gene mutations in 11 different genes have been reported, 50 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 244 genes that, 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 408. The number of human obesity QTLs derived from genome scans continues to grow, and we now have 253 QTLs for obesity-related phenotypes from 61 genome-wide scans. A total of 52 genomic regions harbor QTLs supported by two or more studies. The number of studies reporting associations between DNA sequence variation in specific genes and obesity phenotypes has also increased considerably, with 426 findings of positive associations with 127 candidate genes. A promising observation is that 22 genes are each supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. The electronic version of the map with links to useful publications and relevant sites can be found at http://obesitygene.pbrc.edu.

Genomic variants in polycystic ovary syndrome

The polycystic ovary syndrome (PCOS) is a common disorder in premenopausal women, characterized by the presence, among other traits, of hyperandrogenism, insulin resistance, and hyperinsulinism. The familial aggregation of PCOS lead the interest to the molecular genetic basis of this syndrome, especially to the genes encoding proteins involved in androgen synthesis and the regulation of insulin synthesis and action. Considering the relationship between insulin resistance and chronic inflammation, and the clustering of inflammatory markers in PCOS patients, recent studies focused on the involvement of proinflammatory genotypes on the pathogenesis of PCOS. Mounting evidence suggest at present a complex model of inheritance for PCOS, in which predisposing and protecting genomic variants interact with environmental factors such as obesity and a sedentary lifestyle, finally leading to the classic phenotype of this syndrome. Moreover, the association of hyperandrogenism, insulin resistance and chronic inflammation raised the possibility of an increase risk of cardiovascular disease in women suffering from PCOS. In the present review we will summarize the most important findings published to date regarding the molecular genetic mechanisms underlying the association of PCOS with insulin resistance and chronic inflammation, and the possible interaction of these mechanisms with environmental factors.