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

Upregulation of Cyp19a1 and PPAR-γ in ovarian steroidogenic pathway by Ficus religiosa: A potential cure for polycystic ovary syndrome

ETHNOPHARMACOLOGICAL RELEVANCE

Quite a few plants are in use to treat female infertility and associated problems. Availing the cues from traditional knowledge, phytochemical studies and ethnopharmacological evidences, the aphrodisiac plant Ficus religiosa (F. religiosa) is widely in use to cure infertility in women. For instance, the juice of leaf and aerial root of F. religiosa is reported to normalize the dysregulated menstrual cycle in women. Besides, it is believed that regular circumambulation of F. religiosa during the early hours of the morning helps women in alleviating infertility which could be attributed to the potential phytovolatiles released from F. religiosa. However, the evidences for therapeutic potential of F. religiosa in treating female infertility are arbitrary and mostly anecdotal.

AIM OF THE STUDY

The present study was aimed at examining if extracts of fresh and/or dry leaf of F. religiosa would cure polycystic ovary syndrome (PCOS) in the rat model.

METHODS

Rats were divided into seven groups; control (Group I), PCOS-induced (P.O, Letrozole -1 mg/kg BW for 21 days) and untreated (Group II), PCOS-induced and treated with the leaf extracts of F. religiosa (Groups III-VI), and, PCOS-induced and treated with pioglitazone (Group VII). The estrous intervals, body and organ weights (ovary and uterus), and serum hormones (testosterone, luteinizing hormone [LH], estrogen, and progesterone) were measured, and the expression of Cyp19a1 (aromatase), and Peroxisome Proliferator-Activated Receptor-γ (PPAR-γ) were assessed in the experimental rats. The levels of 3β-hydroxysteroid dehydrogenase (3β-HSD), 17β-hydroxysteroid dehydrogenase (17β-HSD), and antioxidants (MDA, GSH, GPx, SOD, and CAT) were also quantified. Besides, the putative volatile compounds in the esterified leaf extracts were identified using Gas Chromatography-Mass Spectrometry (GC-MS).

RESULTS

Letrozole treatment induced irregular estrous and altered weight of organs and hormonal milieu, which were reverted to normal in leaf extracts-treated PCOS-induced rats. Remarkably, fresh leaf treatment up-regulated Cyp19a1and PPAR-γ and increased the levels of 3β-HSD and 17β-HSD. We found 3-acetoxy-3-hydroxy-propionic acid in fresh and dry leaf extracts, which we attribute to efficacy of the extracts in alleviating PCOS.

CONCLUSION

Put together, our findings suggest the leaves of F. religiosa as potential in alleviating PCOS, mainly due to the presence of putative volatile molecules. Further screening of the leaves of F. religiosa is recommended to identify other key molecules and to develop a systematic therapeutic intervention for PCOS.

Genetic polymorphisms associated with polycystic ovary syndrome among Iranian women

Polycystic ovary syndrome (PCOS) involves abnormalities in ovarian, reproductive, and metabolic systems. Genetic polymorphisms associated with individual differences and variations might be related to complex disorders with unknown causes, including PCOS. Several leading genetic markers with known cellular functions have been identified among Iranian women presenting with PCOS. In particular, the existing evidence shows a significant relationship between PCOS and the following genetic polymorphisms: rs2275913 (interleukin-17A), rs9927163 (interleukin-32), Pro12Ala (peroxisome proliferator-activated receptor-γ), rs17173608 (chemerin), rs2236242 (vaspin), ApaI (vitamin D receptor), and rs7895833 (sirtuin 1). In addition, a higher risk of PCOS is associated with the rs2910164 (microRNA 146a), rs2241766 (adiponectin), -34 T/C (cytochrome 17), and rs1800682 (Fas) polymorphisms. Furthermore, protective effects against PCOS have been reported for the A4223C polymorphism of adenosine deaminase 1. Overall, the available data indicate that Iranian women with PCOS have a higher prevalence of polymorphisms in inflammation- and metabolism-related genes, but not in insulin-related genes. More extensive studies are needed to identify the ethnicity-related genetic associations in PCOS.

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.

Single-nucleotide polymorphism of INS, INSR, IRS1, IRS2, PPAR-G and CAPN10 genes in the pathogenesis of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common and a complex female endocrine disorder, and is one of the leading cause of female infertility. Here, we aimed to investigate the association of single-nucleotide polymorphism of INS, INSR, IRS1, IRS2, PPAR-G and CAPN10 gene in the pathogenesis of PCOS. A hospital-based, observational case-control study was carried on 169 PCOS and 169 control women in the southern region of India. Genotype was carried out by real-time polymerase chain reaction. A chi-square (χ²) test was performed and the genotypes were verified to comply with the Hardy- Weinberg equilibrium. Odds ratio and 95% confidence interval were calculated to assess the relative risk. Comparison of clinical characteristics of women with PCOS and controls reveal an increase in body mass index (BMI), luteinizing hormone / follicle stimulating hormone (LH/FSH) ratio, glucose levels, insulin, testosterone, hirsutism and antral follicular count in PCOS women. The variant rs1801278 (P = 0.002; OR = 2.88; 95% CI = 1.43, 5.80) show an association with PCOS. In the genotypic (P = 0.0002) and allelic models (P = 0.000), significance persisted even after Bonferroni correction. The genotypes of SNPs strongly influence BMI, LH, LH/FSH ratio, ovarian volume and antral follicular count in PCOS women. The study results were suggestive of a positive association between Gly972Arg of IRS1 and PCOS in the south Indian population, while INS, IRS2, PPAR-G and CAPN10 failed to show any association with PCOS in our studied population. Further studies focussing the role of IRS1 are warranted to delineate its implication towards PCOS.

Association of the Pro12Ala Polymorphism with the Metabolic Parameters in Women with Polycystic Ovary Syndrome

AIM:

To investigate the association of peroxisome proliferator-activated receptor gamma (PPARG) Pro12Ala polymorphism with polycystic ovary syndrome (PCOS) and its effect on the metabolic parameters in PCOS women.

METHODS:

The study used PCR to identify the presence of the PPARG Pro12Ala polymorphism in 100 PCOS women and 120 age-matched healthy women. All participants were subjected to anthropometry, biochemical and metabolic evaluation.

RESULTS:

Significant difference in the genotypes distributions of PPARG Pro12Ala polymorphism was observed among PCOS women and controls (p = 0.03). The frequency of the polymorphic allele Ala was significantly higher in PCOS cases than that in the controls (OR = 2.01, p = 0.01). The carries of the variant allele Ala in PCOS women showed significant higher values in body mass index (BMI), systolic and diastolic blood pressure, waist circumference, waist to hip ratio, sum of skin folds, fasting blood glucose, fasting blood insulin, HOMA-IR, fasting triglycerides, total cholesterol and low-density lipoprotein than non-carriers.

CONCLUSION:

The PPARG Pro12Ala polymorphism might contribute to the risk of PCOS and abnormal metabolic parameters and could be considered as a biomarker for early diagnosis and clinic prediction of metabolic complications.

Peroxisome proliferator-activated receptor gamma rs1801282 C>G polymorphism is associated with polycystic ovary syndrome susceptibility: a meta-analysis involving 7,069 subjects

In the peroxisome proliferator-activated receptor gamma (PPARG) gene, a polymorphism (rs1801282 C>G), has been shown to change an amino acid residue and then results in alternation of PPARG function. A number of studies have explored the relationship between PPARG rs1801282 C>G variants and polycystic ovary syndrome (PCOS) risk, but yielding inconsistent findings, especially in Asian population. This study aimed to assess the role of PPARG rs1801282 C>G polymorphism in susceptibility to PCOS. Databases of Pubmed, Embase and China National Knowledge Internet (CNKI) were searched until August 2, 2015. The association of PPARG 1801282 C>G polymorphism with PCOS risk was evaluated by crude odds ratios (ORs) with their 95% confidence intervals (CIs). Finally, there were twenty-three studies involving 3,458 PCOS cases and 3,611 controls included in our pooled analysis. Significant associations were identified between PPARG rs1801282 C>G variants and decreased PCOS risk in three genetic comparison models (OR, 0.78; 95% CI, 0.69-0.89; P < 0.001 for G vs. C; OR, 0.77; 95% CI, 0.68-0.89; P < 0.001 for GG+CG vs. CC and OR, 0.79; 95% CI, 0.68-0.91; P = 0.001 for CG vs. CC). In a subgroup analysis by race, significant correlation was also observed between PPARG rs1801282 C>G variants and decreased PCOS risk in three genetic models: G vs. C (OR, 0.83; 95% CI, 0.71-0.97; P = 0.019) and GG+CG vs. CC (OR, 0.83; 95% CI, 0.70-0.99; P = 0.033) among Caucasians and in one genetic models: G vs. C (OR, 0.72; 95% CI, 0.59-0.88; P = 0.001) among Asians. In summary, our results demonstrate that PPARG rs1801282 C>G polymorphism may be a protective factor for PCOS.

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.