The relationship of the interleukin-6 -174 G>C gene polymorphism with oxidative stress markers in Turkish polycystic ovary syndrome patients

Genetic variants of metabolism and inflammatory pathways, and PCOS risk -Systematic review, meta-analysis, and in-silico analysis

IMPORTANCE

Identification of genetic risk factors for PCOS susceptibility.

OBJECTIVE

To identify genetic risk variants of the genes involved in metabolic or inflammatory pathways.

DATA SOURCES

Relevant literature was identified and extracted from PubMed, Central Cochrane Library, Google Scholar, and Science Direct by using a set of keywords related to pre-determined genes up to 06 May 2023. Study selection and synthesis: PRISMA guidelines were followed to design the protocol which is registered in PROSPERO (CRD42023422501). Pooled odds ratio (OR) and 95% confidence interval (95% CI) for different gene variants were calculated under different genetic models (dominant model, recessive model, additive model, and allele model) by using Review Manager software 4.2.

MAIN OUTCOMES

Metabolic genetic variants FTO rs9939609, IL-6 rs1800795 and CAPN10 rs3842570, rs2975760, and RAB5B rs705702 are associated with PCOS risk.

RESULTS

Forty-four relevant articles have been identified for genes involved in metabolic (n = 23) or inflammatory pathways (n = 21). There is a significant association (p < 0.05) of IL-6 rs1800795 and FTO rs9939609 with increased risk.CAPN10 rs2975760 Ins allele is suggested as a protective factor among only the non-Asian population. Also, a significant association of CAPN10 rs2975760 and RAB5B rs705702 with increased risk among the Asian population is suggested. However, no significant association could be found between CAPN10 rs3792267, rs5030952, and SUMO1P1 rs2272046, and the risk of PCOS in any of the subpopulations analysed. In silico analysis suggests the deleterious effect of IL-6 rs1800795.

CONCLUSION

and relevance: The study suggests the role of various genetic variants for genetic predisposition to PCOS among different subpopulations.

Nitric oxide (NO) levels in patients with polycystic ovary syndrome (PCOS): a meta-analysis

Objective

The pathogenesis of polycystic ovarian syndrome (PCOS) remains unclear, but is known to be related to increased insulin resistance, diabetes, obesity, oxidative stress, inflammation, and cardiovascular disease. No meta-analyses have examined whether PCOS is associated with nitric oxide (NO). Therefore, we aimed to evaluate the association between serum/plasma nitrite levels and PCOS.

Methods

We performed a meta-analysis. To identify eligible original articles, we searched online computerized databases, including EMBASE, Medline, and Web of Science. The characteristics of each single study, as well as the standard mean difference (SMD) with corresponding confidence intervals (CIs), were calculated and subgroup analysis was performed to examine heterogeneity.

Results

We included 12 articles with 16 studies and a total of 895 patients were included in the meta-analysis. We found a significant association between PCOS and serum or plasma nitrite levels, with a pooled SMD of −0.61 (95% CI: −1.05 to −0.16). The final pooled data were determined by the random effects model because significant high heterogeneity (I² = 89%) was found.

Conclusions

Our meta-analysis shows that decreased serum or plasma nitrite levels are associated with PCOS. The pathogenesis of PCOS may be due to endothelial dysfunction; however, further research to confirm this possibility is required.

Association between rs1800795 polymorphism in the interleukin-6 gene and the risk of polycystic ovary syndrome: A meta-analysis

OBJECTIVE

Several published articles have investigated the association between the -174 G/C (rs1800795) polymorphism in the interleukin-6 (IL-6) gene and the risk of polycystic ovary syndrome (PCOS). However, the results were inconsistent. In the present study, a meta-analysis was performed to resolve this inconsistency.

METHODS

Eligible studies reporting an association between the IL-6 rs1800795 polymorphism and PCOS susceptibility were included from PubMed, Embase, Web of Science, and the Cochrane Library up to December 1, 2017. The odds ratio (OR) with the 95% confidence interval (CI) was used to calculate the strength of the associations. Publication bias detection was conducted using Begg test. We used STATA 11.0 software to perform the statistical analyses.

RESULTS

Six articles detailing case-control studies were included, reporting a total of 512 cases and 606 controls. The meta-analysis results indicated that rs1800795 was associated with decreased PCOS susceptibility in the overall population under the allelic model (G vs. C, OR = 0.59, 95% CI: 0.41-0.85, P = .005), the homozygous model (GG vs. CC, OR = 0.45, 95% CI: 0.28-0.73, P = .001), heterozygous model (GG vs. CG, OR = 0.50, 95% CI: 0.26-0.95, P = .036), and the dominant model (GC + CC vs. GG, OR = 0.48, 95% CI: 0.26-0.89, P = .020). However, a threshold P value of .05 was found under the recessive model (CC vs. GG + CG, OR = 0.62, 95% CI: 0.39-1.00).

CONCLUSIONS

This meta-analysis concluded that IL-6 rs1800795 polymorphism has a decreased association with PCOS risk among all populations studied. The results suggested that the IL-6 rs1800795 polymorphism is a protective factor for PCOS susceptibility. Given the limited ethnic groups and sample size, further studies are required to validate the association.

Polymorphisms of Cytokine Genes and Polycystic Ovary Syndrome: A Review

BACKGROUND

Polycystic ovary syndrome (PCOS) is the endocrinopathy that affects women in their reproductive age. The physiopathology involves multifactorial mechanisms, including cytokine gene regulation.

METHODS

The review was conducted in the database PubMed, with articles published between 2005 and 2015. The selected studies evaluated the single-nucleotide polymorphisms (SNPs) of cytokines genes in association with PCOS. Twenty-four studies met the inclusion criteria and showed the SNPs of cytokines that were associated or not with PCOS.

RESULTS

The disease susceptibility was associated with interleukin (IL) 1A, IL1B, IL1RN, and IL6 alleles and genotypes. The tumor necrosis factor (TNF) -1032 C/T genotype and C allele were risk factors and T/T genotype was a protector marker to disease. The IL18 SNPs were not associated with PCOS per se, but IL18-137 C and G alleles were related to the protection of insulin resistance and glucose tolerance, respectively. One research found association between TGFB1 and PCOS. However, the TNF -308, IL10, and interferon (IFN) SNPs did not appear to influence PCOS genetic susceptibility.

CONCLUSIONS

This study sought to contribute and clarify the SNPs in cytokine genes that influence the development of PCOS. Most studies occurred in Asia; most SNPs studied were in IL1B -511, TNF -1031, and IL6-174; and most of them were associated with the susceptibility to PCOS development. Nevertheless, further investigations based on genome-wide association studies and cytokine gene SNPs are needed to better characterize the risk factors to PCOS.

The clinical and biochemical characteristics associated with insulin resistance in non-obese young women. Gynecol Endocrinol 2016;32:767-771. [PMID: 27018331 DOI: 10.3109/09513590.2016.1163671]

AIM

The aim of this study was to investigate the biomarkers of insulin resistance in non-obese women.

DESIGN

This was a retrospective study.

PATIENTS

A total 229 non-obese women (Body mass index: BMI < 25) were evaluated.

MAIN OUTCOME MEASURE(S)

Serum levels of various androgens, cardiovascular risk and metabolic components.

RESULTS

There were no significant differences in the prevalence of polycystic ovary syndrome (PCOS), hyperprolactinemia, or premature ovarian failure (POF) between the non-obese women with and without insulin resistance. Non-obese women with insulin had significantly higher serum thyroid stimulation hormone (TSH) levels and resistin and lower serum adiponectin levels than non-obese women without insulin resistance; however, the inflammatory biomarkers and serum androgen levels did not differ between the two groups. Furthermore, using step-wise multivariate regression analysis applied by the risk factors listed above, TSH was the only predictive factor for insulin resistance in non-obese reproductive-aged women.

CONCLUSIONS

Thyroid function should play an important role in developing insulin resistance for non-obese women. Serum androgens and inflammation might not contribute to insulin resistance in these women.

Interleukin 10 (- 1082 G/A) and (- 819 C/T) gene polymorphisms in Egyptian women with polycystic ovary syndrome (PCOS)

Cytokines play critical roles in the pathogenesis of Polycystic Ovarian Syndrome (PCOS). This work was designed to study the implication of IL10 gene polymorphisms (− 1082 G/A and − 819 C/T) on the susceptibility of Egyptian women to have PCOS. Rotterdam consensus criteria were used to diagnose PCOS patients. Genotyping was performed by single-stranded polymorphism-polymerase chain reaction (SSP-PCR) in 61 PCOS patients and 80 healthy controls, and IL-10 serum levels were measured using Enzyme linked immunosorbent assay (ELISA). The frequency of IL10 − 1082 G/G (46%) genotype was significantly increased (p < 0.001) while the frequency of − 1082 A/A (16%) genotype was significantly decreased (p < 0.05) in PCOS patients compared to controls (14% and 35% for G/G and A/A genotypes; respectively). G allele (65%) is significantly increased (p < 0.01( in PCOS patients while A allele (61%) is significantly increased (p < 0.001( in control subjects. The distribution of IL10 -819 T/T genotype was significantly increased (p < 0.05) in PCOS group. G/G genotype (odd ratio (OR = 5.322) with confidence interval (CI = 2.364–11.982) and the G allele (OR = 2.828 with CI = 1.73–4.61) of − 1082 G/A and T/T genotype of − 819 C/T (OR = 4.18 with CI = 1.26–13.86) could be considered as risk factors for PCOS. IL-10 levels were significantly lower among PCOS patients (313.42 ± 30.10) compared to normal controls (4914.36 ± 303.72). Depending on our preliminary work, IL10 − 1082 G/G might be considered as a host genetic factor for PCOS susceptibility in Egyptian women. Studies concerning other cytokine gene polymorphisms are required to get a better understanding of the pathogenesis of PCOS disease.

Obesity and inflammatory biomarkers in women with polycystic ovary syndrome

OBJECTIVE

To evaluate the roles of obesity and inflammatory biomarkers associated with medical complications in women with PCOS.

STUDY DESIGN

Retrospective, BMI-matched study. A total of 330 patients, including 165 women with PCOS and 165 women without PCOS, were evaluated. The insulin resistance (homeostasis model assessment insulin resistance index - HOMA) and lipid profiles were assessed. The adiponectin, leptin, ghrelin, resistin, anti-müllerian hormone (AMH), sex hormone-binding globulin (SHBG), high sensitivity C-reactive protein (hs-CRP), and interleukin-6 (IL-6) levels were also measured.

RESULTS

Women with PCOS had significantly higher AMH, fasting insulin, total cholesterol, and low-density lipoprotein levels and lower SHBG levels compared with the controls. There was no difference in the serum obesity and inflammatory biomarkers between the PCOS cases and the controls. After adjusting for BMI and age, IL-6 was positively correlated with HOMA, and SHBG was negatively correlated with HOMA, triglyceride, and LDL.

CONCLUSIONS

The serum adipokines levels are not good markers for PCOS. PCOS patients were characterized by their high AMH and low SHBG levels. A low level of SHBG should play an important role in the pathogenesis of the medical complications observed in women with PCOS. Clinical trial registration number NCT01989039.

Oxidative stress and cardiovascular complications in polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is a complex endocrine condition which is associated with metabolic and cardiovascular complications. It is elevated to a metabolic disorder with significant long term health ramification due to the high prevalence of insulin resistance (IR), impaired glucose tolerance, type 2 diabetes (T2D), dyslipidemia and numerous cardiovascular risk factors in PCOS women. This article concentrates on the recent developments in the regulation of oxidative stress (OS) in PCOS and on the association between PCOS and CVD outcomes. The prognostic events that define the severity of PCOS and involvement of cardiovascular risk in PCOS include endothelial dysfunction (ED) and impaired cardiac structure. Fact is that, in PCOS women, the circulating biomarkers of OS are in abnormal levels that are independent of overweight, which depicts the participation of OS in the pathophysiology of this common derangement. In addition, hyperglycemia (HG) per se, promotes reactive oxygen species (ROS) generation in PCOS. When the destructive ROS outbalances the concentration of physiological antioxidants, OS occurs. The resultant OS, directly stimulates hyperandrogenism and causes extensive cellular injury, DNA damage and/or cell apoptosis. To further the burden, the total serum antioxidant level in PCOS women is compromised, which diminishes the body's defense against an oxidative milieu. Thus, it is evident that OS regulates several cellular mechanisms in PCOS. Improving our understanding about the regulation of OS, critical role of ROS and protein biomarkers in PCOS should lead to novel therapeutic strategies in addressing PCOS-induced CVD. Besides, it is possible that the beneficial effects of dietary or therapeutic antioxidants have significant clinical relevance in PCOS.

Meta-analysis of the correlation between IL-6 -174 G/C polymorphism and polycystic ovarian syndrome

AIM

The correlation between interleukin-6 (IL-6) gene polymorphism and polycystic ovary syndrome (PCOS) has been reported, but the conclusions are controversial. The present study was aimed to evaluate the association between IL-6 -174 G/C polymorphism and susceptibility of PCOS by meta-analysis.

MATERIAL AND METHODS

A systematic search on Medline, Embase, CNKI, Wanfang Data and VIP databases containing Chinese and English studies was conducted electronically using specific eligibility criteria. Meta-analysis was performed using Review Manager 5.2 software after Hardy-Weinberg equilibrium test. Effect sizes of odds ratio and 95% confidence interval (CI) were calculated and combined appropriately. To verify the reliability of the results, subgroup analyses and sensitivity analyses were performed.

RESULTS

Four selected studies containing 351 cases and 464 control participants were included. The pooled odds ratio between IL-6 -174 G/C polymorphism and susceptibility of PCOS under allele (C/G), dominant (CC+GC/GG) and recessive (CC/GG+GC) models were 0.63 (95%CI, 0.41-0.96), 0.53 (95%CI, 0.26-1.08) and 0.67 (95%CI, 0.39-1.16), respectively. The result under allele model was unstable in sensitivity analysis. Subgroup analysis showed that the correlation between IL-6 -174 G/C polymorphism and susceptibility of PCOS was not statistically significant in the studies that conformed to the Hardy-Weinberg equilibrium.

CONCLUSION

IL-6 -174 G/C polymorphism may be not related to susceptibility of PCOS. Nevertheless, further studies with large samples and studies considering other single-nucleotide polymorphisms of the IL-6 gene are needed to confirm our findings.

Associations between TNF-α and interleukin gene polymorphisms with polycystic ovary syndrome risk: a systematic review and meta-analysis

BACKGROUND

The associations between TNF-α and Interleukin gene polymorphisms and polycystic ovary syndrome (PCOS) risk have been studied in numerous epidemiological studies, but the results remain controversial. To investigate whether these polymorphisms facilitate susceptibility to PCOS, we conducted a comprehensive systematic review and meta-analysis.

METHODS

PubMed, Embase, Web of Science, Medline, CNKI, and Google Scholar were searched to obtain the genetic association studies according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Odds ratios (OR) with corresponding 95 % confidence intervals (CI) were used to assess the strengths of the associations. Funnel plots and Egger's tests were performed to test for possible publication bias. All statistical analyses were performed using Review Manager 5.2 and STATA11.0.

RESULTS

Eighteen articles were included in the final meta-analysis. The studies involved the following polymorphisms: TNF-α -308G > A, TNF-α -805C>T, TNF-α -1031 T>C, IL-1A -889C>T, IL-1B -511C>T, IL-1B +3953 T>C, IL-6 -174G>C, IL-10 -819C>T, IL-10 -1082A>G, IL-18 -607C>A, and IL-18 -137G>C. Our results show a significant association between PCOS risk and the TNF-α -1031 T>C polymorphism (For TC+CC vs. TT: OR=2.09, 95 % CI=1.58-2.76, p<0.0001. For C allele vs. T allele: OR=1.67, 95 % CI=1.33-2.09, p<0.0001) and between PCOS risk and the IL-6 -174>C polymorphism (For CC+GC vs. GG: OR=0.49, 95 % CI=0.25-0.95, p=0.03. For CC vs. GG: OR=0.48, 95 % CI=0.28-0.80, p=0.005. For C vs. G: OR=0.60, 95 % CI=0.42-0.87, p=0.007). No associations were found with the other genetic models.

CONCLUSION

The results of the meta-analysis suggest positive associations between the TNF-α -1031 T>C and IL-6 -174G>C polymorphisms and the risk of PCOS. No associations are found between PCOS risk and the TNF-α -308G>A, TNF-α -805C>T, IL-1A -889C>T, IL-1B -511C>T, IL-1B +3953C>T, IL-10 -819C>T, IL-10 -1082 A>G, IL-18 -607C>A, and IL-18 -137G>C polymorphisms. However, due to the heterogeneity and low quality of the studies related to PCOS polymorphisms in the meta-analysis, the results should be interpreted with caution. Future multi-ethnicity studies of homogeneous populations of PCOS patients with larger sample sizes and well-matched controls are needed.

Polycystic Ovary Syndrome: Important Underrecognised Cardiometabolic Risk Factor in Reproductive-Age Women

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder amongst women of reproductive age. Although PCOS is diagnosed exclusively based on reproductive criteria, it is also a metabolic disorder. Insulin resistance, impaired glucose tolerance, type 2 diabetes mellitus, obesity, and dyslipidemia are more common in women with PCOS than in age-comparable women without PCOS. Many of the metabolic abnormalities that manifest in PCOS are worsened by the concurrent incidence of obesity. However, some of these metabolic perturbations occur even in lean women with PCOS and therefore are rightfully recognized as intrinsic to PCOS. The intrinsic factors that produce these metabolic disturbances are reviewed in this paper. The consequences of obesity and the other metabolic aberrations are also discussed. The metabolic perturbations in PCOS patients lead to chronic low-grade inflammation and to cardiovascular impairments that heighten the risk of having cardiovascular disease. Even though many studies have shown an elevation in surrogate biomarkers of cardiovascular disease in PCOS women, it is still not clear to what extent and magnitude the elevation precipitates more frequent and earlier events.

Detailed characterisation of circulatory nitric oxide and free radical indices--is there evidence for abnormal cardiovascular homeostasis in young women with polycystic ovary syndrome?

OBJECTIVE

To assess circulating biochemical indices of endothelial function and nitro-oxidative stress in women with polycystic ovary syndrome (PCOS).

DESIGN

Case-control study.

POPULATION

Seventeen women with PCOS and eighteen age- and body mass index-matched healthy volunteers.

METHODS

Nitric oxide (NO) metabolite levels were assessed by chemiluminescence. Electron paramagnetic resonance spectroscopy with spin trapping was used to assess oxidative stress ex vivo and in vitro. Antioxidant capacity was measured using oxygen radical absorbance.

MAIN OUTCOME MEASURES

Biochemical indices of endothelial function, including NO metabolites, lipid-derived radicals and antioxidant capacity.

RESULTS

Plasma NO metabolites were similar in the two groups (nitrite: 257±116 nmol/l [PCOS], 261±135 nmol/l [controls] P=0.93; nitrate: 27±7 μmol/l [PCOS], 26±6 μmol/l [controls] P=0.89). Alkoxyl free radicals (lipid-derived) were detected as the dominant species, but levels were not different between women with PCOS and controls whether measured directly ex vivo (median 7.2 [range 0.17-16.73]e6 arbitrary units [a.u.] and 7.2 [1.7-11.9]e6 a.u., respectively, P=0.57) or when stimulated in vitro to test radical generation capacity (1.23 [0.3-5.62]e7 a.u. and 1.1 [0.48-15.7]e7 a.u. respectively, P=0.71). In regression analysis, visceral fat area was independently associated with in vitro oxidative potential (β=0.6, P=0.002). Total plasma antioxidant capacity (94±30% [PCOS], 79±24% [controls], P=0.09) and plasma hydroperoxides (7.5±4 μmol/l [PCOS], 6.7±5 μmol/l [controls], P=0.21) were not different between groups. However, lipophilic antioxidant capacity was lower in women with PCOS compared with controls (92±32 and 125±48%, respectively, P=0.02).

CONCLUSIONS

Young overweight women with PCOS display a reduced lipophilic antioxidant capacity compared with healthy volunteers, but no change in circulating free radicals or nitro-oxidative stress.

Circulating markers of oxidative stress and polycystic ovary syndrome (PCOS): a systematic review and meta-analysis

BACKGROUND Oxidative stress might be associated with polycystic ovary syndrome (PCOS), but relatively small studies published to date do not permit reaching a definitive conclusion. We aimed at conducting a systematic review and meta-analysis of studies evaluating circulating markers of oxidative stress in patients with PCOS. METHODS We conducted a systematic review of studies reporting circulating markers of oxidative stress in women with PCOS and controls published up to June 2012, using Entrez PubMed and EMBASE online facilities. Meta-analysis calculated standardized mean differences (SMDs) and 95% confidence intervals (95CI). RESULTS From 1633 potential studies identified electronically, 68 studies, including 4933 PCOS patients and 3671 controls, were selected. For each of nine circulating markers of oxidative stress, an individual meta-analysis was conducted. Compared with control women, patients with PCOS presented higher circulating concentrations of homocysteine (23% increase, SMD 0.6, 95CI, 0.4-0.8), malondialdehyde (47% increase, SMD 1.9, 95CI 1.2-2.6) and asymmetric dimethylarginine (36% increase, SMD 1.1, 95CI 0.6-1.6), and increased superoxide dismutase activity (34% increase, SMD 1.0, 95CI 0.5-1.4) and decreased glutathione levels (50% decrease, SMD -3.7, 95CI -6.2 to -1.2) and paraoxonase-1 activity (32% decrease, SMD -0.9, 95CI -1.3 to -0.4). Similar results were found when restricting the analyses to studies in which patients and controls were matched for age and body mass index. CONCLUSIONS Circulating markers of oxidative stress are abnormal in women with PCOS independent of weight excess. This finding suggests that oxidative stress may participate in the pathophysiology of this common disorder.

Apolipoprotein E-containing HDL-associated platelet-activating factor acetylhydrolase activities and malondialdehyde concentrations in patients with PCOS

PAF and PAF-like oxidized phospholipids hydrolysed by platelet-activating factor (PAF) acetylhydrolase (AH) are potent lipid mediators involved in inflammation and atherosclerosis. Apolipoprotein (apo) E-containing high-density lipoprotein (HDL) has antioxidant, anti-inflammatory and anti-atherogenic properties. The study investigated apoE-containing HDL-associated PAF-AH (HDL-PAF-AH) and total (apoE-containing+apoE-poor) HDL-PAF-AH activities as well as malondialdehyde (MDA) concentration in 291 patients with polycystic ovary syndrome (PCOS) using the Rotterdam consensus criteria and 281 control women. Compared with the control women, patients with hyperandrogenism+oligo/anovulation+polycystic ovaries (PCO) or hyperandrogenism+PCO had lower total, apoE-containing and apoE-poor HDL-PAF-AH activities, while those with oligo/anovulation+PCO showed decreased total and apoE-poor HDL-PAF-AH activities. Other factors including insulin resistance and obesity in PCOS had the adverse effects associated with the HDL-PAF-AH activities. Serum MDA concentration was associated with PCOS, hyperandrogenism, insulin resistance and hypertriglyceridaemia in patients with PCOS. Decreased total and apoE-containing HDL-PAF-AH activities and increased serum MDA concentration may contribute to the pathogenesis of PCOS and potentially link to related complications responsible for oxidative stress and inflammation such as an increased risk for type 2 diabetes mellitus and/or future cardiovascular diseases in PCOS patients.

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.

Circulating inflammatory markers in polycystic ovary syndrome: a systematic review and metaanalysis

OBJECTIVE

To perform a review and metaanalysis of the studies evaluating the status of serum inflammatory markers in women with polycystic ovary syndrome (PCOS).

DESIGN

Systematic review and metaanalysis of articles published in English before January 2010 and identified using the PubMed search engine.

SETTING

Academic hospital.

PATIENT(S)

Women with PCOS and appropriate controls.

INTERVENTION(S)

Measurement of serum concentrations of inflammatory markers by high-sensitivity techniques.

MAIN OUTCOME MEASURE(S)

Metaanalyses of the mean difference in serum C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) concentrations among patients with PCOS and appropriate controls, applying random-effects models to limit interstudy variability, and using appropriate estimates of evidence dissemination bias.

RESULT(S)

Metaanalysis of the 31 articles meeting inclusion criteria showed that circulating CRP was 96% higher in women with PCOS compared to controls (95% confidence interval, 71%-122%; z = 7.32) without evidence of dissemination bias (Egger's regression intercept, 0.45; 95% confidence interval, -2.30 to 3.21). These findings persisted after excluding five studies with mismatches in body mass, frequency of obesity, or both, between women with PCOS and controls. Metaanalyses involving 10 studies of IL-6, and nine studies of TNF-α revealed no statistically significant differences between PCOS and controls.

CONCLUSION(S)

Women with PCOS exhibit an elevation in circulating CRP that is independent of obesity. This finding corroborates existing molecular evidence of the chronic low-grade inflammation that may underpin the pathogenesis of this disorder.

Tumor necrosis factor alpha (-308), interleukin-6 (-174) and interleukin-10 (-1082) gene polymorphisms in polycystic ovary syndrome

OBJECTIVE

The imbalance between pro- and anti-inflammatory cytokines and polymorphism of cytokine genes may play a role in the etiology of the polycystic ovary syndrome (PCOS). The aim of this study was to investigate the association of polymorphisms of TNFalpha, IL-6 and IL-10 genes with the occurrence and the clinical/laboratory characteristics of PCOS in the Turkish population.

STUDY DESIGN

Single nucleotide polymorphisms (SNPs) of TNFalpha (-308 G/A), IL-6 (-174 G/C), IL-10 (-1082 G/A) genes in DNA from peripheral blood leukocytes of 97 PCOS patients and 95 healthy control women were investigated.

RESULTS

There is a tendency toward lower frequency of the IL-6 CC genotype and C allele among PCOS women compared with healthy controls although the difference did not reach a significant level. No notable differences were observed in allele or genotype frequencies for TNFalpha and IL-10 genes between groups. The concomitant presence of wild homozygous TNFalpha genotype together with mutant IL-6 C allele has a protective effect against PCOS with an OR=0.45 (95% CI=0.23-0.86). While TNFalpha (-308) and IL-10 (-1082) genotypes did not influence clinical/laboratory parameters in PCOS, IL-6 (-174) CC or pooled CG+CC genotypes have lower glucose, insulin, HOMA, cholesterol, triglyceride, and LDL-C, and higher GIR and HDL-C values than GG genotypes.

CONCLUSIONS

We suggest that the IL-6 promoter region polymorphism may be related to occurrence and metabolic abnormalities seen in PCOS in the Turkish population. However, more studies with larger sample size are necessary to support our findings in other populations before any statement can be made about the relationship between PCOS and cytokine polymorphism.