Relationship between leptin receptor and polycystic ovary syndrome

Association between leptin receptor polymorphisms and polycystic ovary syndrome risk: a meta-analysis based on 11 studies

OBJECTIVE

Published evidence indicated that the leptin receptor (LEPR) gene polymorphisms are associated with polycystic ovary syndrome (PCOS) risk. However, studies on the association between the polymorphisms of LEPR gene are inconsistent or even controversial.

MATERIAL AND METHODS

We conducted this meta-analysis to explore the more precise relationship between LEPR polymorphisms and PCOS risk. Relevant articles were searched with five online databases up to March 1 2023. Odds ratios (OR) with 95% confidence intervals (CI) were selected to examine the statistical strength of each genetic model. Moreover, RNA secondary structure and variant effects of these loci were examined with in silico analysis.

RESULTS

Overall, 11 publications were analyzed, and the pooled results did not present any significant association between rs1137101 A/G polymorphism and PCOS risk in general population and some subgroup analysis. But the significant association were observed in Asian population (AG vs. AA: OR = 0.51, 95%CI = 0.32-0.81, p = .01, I2=0%; AG + GG vs. AA: OR = 0.41, 95%CI = 0.26-0.65, p < .01, I2=25.9%). Moreover, similar positive associations were also observed in rs1805096 polymorphism with PCOS risk.

CONCLUSION

In summary, our meta-analysis suggested that the LEPR gene polymorphisms might be associated with PCOS susceptibility. Owing to the limited studies and small sample size in our meta-analysis, more well-designed studies from different races were needed to be conducted to verify the current results.

Effect of green cardamom on the expression of genes implicated in obesity and diabetes among obese women with polycystic ovary syndrome: a double blind randomized controlled trial

BACKGROUND

Polycystic ovary syndrome (PCOS) is an endocrine disease in which related to obesity, metabolic disorders and is considered as one of the main causes of infertility in women. This trial was investigated the effects of green cardamom on the expression of genes implicated in obesity and diabetes among obese women with PCOS.

METHODS

One hundred ninety-four PCOS women were randomly divided two groups: intervention (n = 99; 3 g/day green cardamom) and control groups (n = 95). All of them were given low calorie diet. Anthropometric, glycemic and androgen hormones were assessed before and after 16-week intervention. The reverse transcription-polymerase chain reaction (RT-PCR) method was used to measure fat mass and obesity-associated (FTO), peroxisome proliferative activating receptor- (PPAR-), carnitine palmitoyltransferase 1A (CPT1A), acetyl-CoA carboxylase beta (ACAB), leptin receptor (LEPR), ghrelin, and lamin A/C (LAMIN) genes expression in each group.

RESULTS

Anthropometric indices were significantly decreased after intervention in both two studied groups. Glycemic indices and androgen hormones were significantly improved in the intervention group compared to the control group. The expression levels of FTO, CPT1A, LEPR, and LAMIN were significantly downregulated compared to control group (P < 0.001), as well as, PPAR-y was significantly upregulated in the intervention group after intervention with green cardamom compared to control group (P < 0.001).

CONCLUSION

This current study showed that the administration of green cardamom is a beneficial approach for improving anthropometric, glycemic, and androgen hormones, as well as obesity and diabetes genes expression in PCOS women under the low-calorie diet.

TRIAL REGISTRATION

This trial was registered with the Iranian Clinical Trials Registry (registration number: IRCT20200608047697N1). 1 August, 2020; https://www.irct.ir/trial/48748.

Targeting adipokines in polycystic ovary syndrome and related metabolic disorders: from experimental insights to clinical studies

Polycystic ovary syndrome (PCOS) affects approximately 15% of women of reproductive age worldwide. It is the most prevalent endocrine disorder with marked risks for female infertility, type 2 diabetes mellitus (T2DM), psychiatric disorders and gynecological cancers. Although the pathophysiology of PCOS remains largely elusive, growing evidence suggests a close link with obesity and its related metabolic disorders. As a highly active endocrine cell population, hypertrophic adipocytes in obesity have disturbed production of a vast array of adipokines, biologically active peptides that exert pleiotropic effects on homeostatic regulation of glucose and lipid metabolism. In parallel with their crucial roles in the pathophysiology of obesity-induced metabolic diseases, adipokines have recently been identified as promising targets for novel therapeutic strategies for multiple diseases. Current treatments for PCOS are suboptimal with insufficient alleviation of all symptoms. Novel findings in adipokine-targeted agents may provide important insight into the development of new drugs for PCOS. This Review presents an overview of the current understanding of mechanisms that link PCOS to obesity and highlights emerging evidence of adipose-ovary crosstalk as a pivotal mediator of PCOS pathogenesis. We summarize recent findings of preclinical and clinical studies that reveal the therapeutic potential of adipokine-targeted novel approaches to PCOS and its related metabolic disorders. We also discuss the critical gaps in knowledge that need to be addressed to guide the development of adipokine-based novel therapies for PCOS.

The Complex Roles of Adipokines in Polycystic Ovary Syndrome and Endometriosis

Polycystic ovary syndrome (PCOS) and endometriosis are frequent diseases of the female reproductive tract causing high morbidity as they can significantly affect fertility and quality of life. Adipokines are pleiotropic signaling molecules secreted by white or brown adipose tissues with a central role in energy metabolism. More recently, their involvement in PCOS and endometriosis has been demonstrated. In this review article, we provide an update on the role of adipokines in both diseases and summarize previous findings. We also address the results of multi-omics approaches in adipokine research to examine the role of single nucleotide polymorphisms (SNPs) in genes coding for adipokines and their receptors, the secretome of adipocytes and to identify epigenetic alterations of adipokine genes that might be conferred from mother to child. Finally, we address novel data on the role of brown adipose tissue (BAT), which seems to have notable effects on PCOS. For this review, original research articles on adipokine actions in PCOS and endometriosis are considered, which are listed in the PubMed database.

Pathogenetic analysis of polycystic ovary syndrome from the perspective of omics

Polycystic ovary syndrome (PCOS) is the most common gynecological endocrine disease, involving multiple genes, multiple pathways, and complex hormone secretion processes. Hence, the pathogenesis of PCOS cannot be explained by a single factor. Omics analysis includes genomics, transcriptomics, and proteomics, which are fast and effective methods for studying the pathogenesis of diseases. PCOS is primarily characterized by androgen excess, and reproductive and metabolic dysfunctions. The application of omics analysis in the body fluids, blood, cells or tissues of women with PCOS offers the potential for unexpected molecular advantages in explaining new mechanisms of PCOS etiology and pathophysiology, and provides new perspectives for identifying potential biomarkers and developing new therapeutic targets. At present, several omics analyses have been applied to produce complex datasets. In this manuscript, the recent advances in omics research on PCOS are summarized, aiming at an important and parallel review of the newly published research.

Association of leptin G2548A and leptin receptor Q223R polymorphisms and their serum levels with infertility and recurrent pregnancy loss in Iranian women with polycystic ovary syndrome

BACKGROUND

Adipokine leptin plays a crucial role in metabolic and reproductive functions. Leptin receptor has a soluble form that binds to leptin, thus modulating its level in the circulation. It has been indicated that the levels of leptin and leptin receptor and also LEP rs7799039 and LEPR rs1137101 polymorphisms are associated with metabolic disorders. In the present study, we assessed the levels of leptin and soluble leptin receptor (sOB-R), and also the frequency of rs7799039 and rs1137101 polymorphisms in healthy fertile women and patients with polycystic ovary syndrome (PCOS), inclusive of PCOS-infertile and PCOS-recurrent pregnancy loss (RPL) subjects.

METHODS

A total of 324 PCOS patients- including 199 infertile cases and 125 patients with a history of RPL- and 144 healthy controls were enrolled in this study. Biochemical parameters and plasma leptin and sOB-R levels were measured by ELISA and the genotypes of rs7799039 and rs1137101 polymorphisms were determined using PCR- RFLP.

RESULTS

Plasma leptin and sOB-R levels were significantly higher and lower in PCOS, PCOS-infertile and PCOS RPL groups, respectively. The GG genotype frequencies of rs7799039 and rs1137101 polymorphisms were significantly different between PCOS-infertile women and non-PCOS subjects (P = 0.043, OR = 0.47, 95% CI = 0.22-0.97, and P = 0.01, OR = 0.31, 95% CI = 0.12-0.75, respectively). Increased LEP levels were associated with the risk of PCOS and RPL in women with PCOS (P = 0.039, OR = 1.203, 95%CI = [1.009-1.435] and P = 0.012, OR = 1.267, 95% CI = [1.054-1.522], respectively).

CONCLUSION

Polymorphisms rs7799039 and rs1137101 and circulating leptin and sOB-R levels were associated with infertility in Iranian women with PCOS. Further studies are needed to reveal the role of leptin in PCOS pathogenesis.

Androgens regulate ovarian gene expression by balancing Ezh2-Jmjd3 mediated H3K27me3 dynamics

Conventionally viewed as male hormone, androgens play a critical role in female fertility. Although androgen receptors (AR) are transcription factors, to date very few direct transcriptional targets of ARs have been identified in the ovary. Using mouse models, this study provides three critical insights about androgen-induced gene regulation in the ovary and its impact on female fertility. First, RNA-sequencing reveals a number of genes and biological processes that were previously not known to be directly regulated by androgens in the ovary. Second, androgens can also influence gene expression by decreasing the tri-methyl mark on lysine 27 of histone3 (H3K27me3), a gene silencing epigenetic mark. ChIP-seq analyses highlight that androgen-induced modulation of H3K27me3 mark within gene bodies, promoters or distal enhancers have a much broader impact on ovarian function than the direct genomic effects of androgens. Third, androgen-induced decrease of H3K27me3 is mediated through (a) inhibiting the expression and activity of Enhancer of Zeste Homologue 2 (EZH2), a histone methyltransferase that promotes tri-methylation of K27 and (b) by inducing the expression of a histone demethylase called Jumonji domain containing protein-3 (JMJD3/KDM6B), responsible for removing the H3K27me3 mark. Androgens through the PI3K/Akt pathway, in a transcription-independent fashion, increase hypoxia-inducible factor 1 alpha (HIF1α) protein levels, which in turn induce JMJD3 expression. Furthermore, proof of concept studies involving in vivo knockdown of Ar in the ovary and ovarian (granulosa) cell-specific Ar knockout mouse model show that ARs regulate the expression of key ovarian genes through modulation of H3K27me3.

The Effect of Leptin Receptor Gene Polymorphisms (R223Q and P1019P) in Susceptibility to Polycystic Ovarian Syndrome in Kurdish Women

Background

Polycystic ovary syndrome (PCOS) is the known endocrinopathy disorder in the reproductive phase of women's life. More than half of the women with PCOS suffer from obesity which impacts the ovarian functions by leptin levels. Here the R223Q and P1019P polymorphisms of leptin receptor (LEPR) gene were examined in PCOS patients of Kurdish women from west of Iran.

Materials and Methods

In this case-control study, one hundred women with PCOS and 100 healthy women bearing similar age range were selected based on Rotterdam diagnostic criteria. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to genotype polymorphisms LEPR (R223Q and P1019P), by respectively the BsaWI and NcoI restriction enzymes. Pearson's chi-square (χ2) test was used to analyze the variation in genetic distributions and unconditional logistic regression model was used to calculate the odds ratio (OR; 95% CI).

Results

Genotype frequencies of the R223Q and P1019P polymorphisms showed significant difference between the patients with PCOS compared to the controls. G allele (R223Q) reduced the risk of PCOS about 0.49-fold (P<0.001). While, T allele (P1019P) increased the risk of PCOS 2.69-fold (P<0.001).

Conclusion

It can be concluded that the R223Q and P1019P polymorphisms showed a significant association with PCOS susceptibility risk. It seems that G allele (R223Q) with reducing OR had a protective effect on this syndrome, while T allele (P1019P) with increasing OR was a risk factor for PCOS.

Contrasting association of Leptin receptor polymorphisms and haplotypes with polycystic ovary syndrome in Bahraini and Tunisian women: a case-control study

BACKGROUND

The present study examined the contribution of ethnicity to the association of leptin receptor gene (LEPR) gene variants with polycystic ovary syndrome (PCOS) in Tunisian and Bahraini Arabic-speaking women.

METHODS

Subjects consisted of 320 women with PCOS, and 446 eumenorrhic women from Tunisia, and 242 women with PCOS and 238 controls from Bahrain. Genotyping of (exonic) rs1137100 and rs1137101 and (intronic) rs2025804 LEPR variants was done by allelic exclusion.

RESULTS

The minor allele frequencies (MAFs) of rs1137100 and rs1137101 were significantly different between PCOS cases and control women from Bahrain but not Tunisia, and LEPR rs1137101 was associated with increased PCOS susceptibility only in Bahraini subjects. Furthermore, rs1137100 was associated with decreased PCOS risk among Bahrainis under codominant and recessive models; rs1137100 was negatively associated with PCOS in Tunisians after controlling for testosterone. In addition, rs2025804 was associated with increased PCOS risk among Tunisian but not Bahraini women, after adjusting for key covariates. Negative correlation was seen between rs1137101 and triglycerides in Tunisians, while homeostasis model assessment of insulin resistance (HOMA-IR) and insulin correlated with rs2025804 and rs1137101 among Bahraini subjects, and rs1137101 correlated with estradiol and prolactin. Taking TAG haplotype as common, positive association of TAA and negative association of TGG haplotype with PCOS was seen among Bahraini women; no three-locus PCOS-associated haplotypes were found in Tunisians.

CONCLUSIONS

The present study is the first to demonstrate the contribution of ethnicity to the association of LEPR gene variants with PCOS, thereby highlighting the significance of controlling for ethnicity in gene association investigations.

Genetic construction between polycystic ovarian syndrome and type 2 diabetes

Polycystic ovarian syndrome (PCOS) in reproductive-aged women is identified to be one of the endocrine disorders. This heterogeneous disorder is categorized through oligo-anovulation and hyperandrogenemia. National institutes of health and Rotterdam criterions were used to diagnose PCOS women. Type 2 Diabetes (T2D) is one of the complications in PCOS which is connected through insulin resistance (IR), which is a condition in which liver, muscles and fat infrequently respond to the hormones, and this leads to extreme IR and consequently leads to T2D disease. PCOS is inherited by the autosomal dominant mode of inheritance and may also with the different intricate patterns. Till now, many studies have been performed in PCOS with the genes identified by T2D and till now no studies have shown the similar genetic association and pathophysiology between both the diseases. So, the current review aims to investigate the genetic relation between PCOS and T2D and why both the diseases cannot be reverted. In this review, published data were screened with the T2D related genes and single nucleotide polymorphisms in PCOS women. The case-control, hospital-based and meta-analysis molecular studies disclosed both positive and negative connotations. Genetically, no relationship has been established between PCOS and T2D. Maximum studies have shown as PCOS women had developed T2D later in life because as a risk-factor, but none of the studies documented T2D women having developed PCOS as a risk factor. Apart from this, the disease PCOS is developed in women with reproductive age and T2D develops in both the men and women during adulthood. This review concludes as there is a genetic relation only in between PCOS and T2D, but not with T2D to PCOS and further it cannot be explicitly reverted from T2D to PCOS.

Relationship of Serum Leptin and Reproductive Hormones in Unexplained Infertile and Fertile Females

OBJECTIVE

To investigate the relationship between serum leptin and reproductive hormones in females with unexplained infertility (UI).

METHODOLOGY

It was a case-control study conducted in the Gynecology and Obstetrics Department and Infertility Clinic, Jinnah Postgraduate Medical Center (JPMC), Karachi, Pakistan. A total of 235 primary infertile females with an unidentified cause of infertility were selected from the Infertility Clinics. The patients were excluded if they were found to have polycystic ovary syndrome, endometriosis, tubal blockage, irregular menstrual cycles, hyperthyroidism, hypothyroidism, hyperprolactinemia, hyperandrogenemia, fasting blood sugar >110 mg/dl, and male factor infertility. A total of 205 healthy, fertile females were selected from the general population. The blood samples of both groups were collected on the 12th and 21st day of their menstrual cycle. Serum leptin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and E2 levels were measured. Statistical analysis was executed using the SPSS version 16 (SPSS Inc., Chicago, IL).

RESULTS

No significant difference was observed in leptin values of fertile and UI females, 37.110±1.19 vs. 35.321±0.901. In the preovulatory phase (12th day) of the cycle, infertile subjects with body mass index (BMI) <20 and 20-24.9 had significantly higher values for leptin (p<0.05), whereas, with an increase in BMI, leptin levels were reduced in these females. Leptin was reduced further in the luteal phase of infertile females with BMI 25-30, with a significantly lower value for FSH (p<0.005), LH (p<0.005), and estradiol (p<0.005. In infertile subjects, it correlated with estradiol (r=0.501, p<0.005), BMI (r=0.903, p<0.001), and progesterone (r=0.146, p<0.05).

CONCLUSION

Low levels of leptin observed to have an increase in the BMI of UI females were associated with a reduced estradiol and progesterone production in the luteal phase of the cycle.

The influence of the rs1137101 genotypes of leptin receptor gene on the demographic and metabolic profile of normal Saudi females and those suffering from polycystic ovarian syndrome

BACKGROUND

Polycystic ovarian syndrome (PCOS) is of frequent occurrence in Saudi females and is often associated with obesity, insulin resistance, hypogonadotropic hypogonadism, and infertility. Since these features are also associated with leptin receptor (LEP-R) deficiency, several studies have attempted to link LEP-R gene polymorphisms to PCOS.

METHODS

The purpose of this study is to assess the possible association of LEP-R gene polymorphism (rs1137101) with the main obesity-linked metabolic parameters in Saudi female patients affected by PCOS. A cohort of 122 Saudi female subjects, attending the outpatient's clinics at Makkah, Saudi Arabia and diagnosed with PCOS was investigated. Metabolic parameters in serum samples, including lipidogram, glucose, leptin, ghrelin and insulin and obesity markers (BMI, W/H ratio, HOMA) were assayed and compared with values from 130 healthy female volunteers (controls). The genotyping of rs1137101 polymorphism in the leptin receptor gene by amplification (PCR) followed by DNA sequencing, was conducted in both groups (PCOS and controls).

RESULTS

Waist/hip ratio (W/H ratio), leptin serum levels and triglycerides appeared to be associated with PCOS but, aside from W/H ratio (AA s GG p = 0.009), this association also occurred for controls. No significant association in the leptin gene polymorphic locus rs1137101 with PCOS was seen in the results of the present study. In the control group, BMI, W/H ratio, leptin, Insulin, and HOMA-IR were significantly higher in the GG genotype compared to AA.

CONCLUSION

Despite previous suggestion about a relationship between rs1137101, serum leptin levels, and PCOS, our studies do not show any statistical association and further investigations; possibly by also evaluating obese patients should be needed to elucidate this issue better.

Leptin action in normal and pathological pregnancies

Leptin is now considered an important signalling molecule of the reproductive system, as it regulates the production of gonadotrophins, the blastocyst formation and implantation, the normal placentation, as well as the foeto-placental communication. Leptin is a peptide hormone secreted mainly by adipose tissue, and the placenta is the second leptin-producing tissue in humans. Placental leptin is an important cytokine which regulates placental functions in an autocrine or paracrine manner. Leptin seems to play a crucial role during the first stages of pregnancy as it modulates critical processes such as proliferation, protein synthesis, invasion and apoptosis in placental cells. Furthermore, deregulation of leptin levels has been correlated with the pathogenesis of various disorders associated with reproduction and gestation, including polycystic ovary syndrome, recurrent miscarriage, gestational diabetes mellitus, pre-eclampsia and intrauterine growth restriction. Due to the relevant incidence of the mentioned diseases and the importance of leptin, we decided to review the latest information available about leptin action in normal and pathological pregnancies to support the idea of leptin as an important factor and/or predictor of diverse disorders associated with reproduction and pregnancy.

LEPR gene polymorphism and plasma soluble leptin receptor levels are associated with polycystic ovary syndrome in Han Chinese women

Aim: To investigate the association of LEPR polymorphisms and plasma leptin and soluble leptin receptor (sOB-R) levels with polycystic ovary syndrome (PCOS) in Chinese women. Patients & methods: LEPR Lys109Arg (rs1137100) and Gln223Arg (rs1137101) polymorphisms of PCOS patients and the controls were genotyped. Plasma leptin and sOB-R levels of two groups were measured. Results: The genotypic distributions of Lys109Arg (rs1137100) differed between the PCOS and control groups. Plasma sOB-R levels increased significantly in PCOS patients and were associated with PCOS independent of BMI. Furthermore, luteinizing hormone, triglyceride and fasting blood glucose correlated significantly to PCOS patients’ sOB-R levels. Conclusion: LEPR Lys109Arg (rs1137100) was associated with PCOS susceptibility and genotype AA was deduced to be a protective factor for PCOS; sOB-R levels might be recognized as a new indicator for the severity of PCOS.

From Placenta to Polycystic Ovarian Syndrome: The Role of Adipokines

Adipokines are cytokines produced mainly by adipose tissue, besides many other tissues such as placenta, ovaries, peripheral-blood mononuclear cells, liver, muscle, kidney, heart, and bone marrow. Adipokines play a significant role in the metabolic syndrome and in cardiovascular diseases, have implications in regulating insulin sensitivity and inflammation, and have significant effects on growth and reproductive function. The objective of this review was to analyze the functions known today of adiponectin, leptin, resistin, and visfatin from placenta throughout childhood and adolescence. It is well known now that their serum concentrations during pregnancy and lactation have long-term effects beyond the fetus and newborn. With regard to puberty, adipokines are involved in the regulation of the relationship between nutritional status and normal physiology or disorders of puberty and altered gonadal function, as, for example, premature pubarche and polycystic ovarian syndrome (PCOS). Cytokines are involved in the maturation of oocytes and in the regular progression of puberty and pregnancy.

Genetics of PCOS: A systematic bioinformatics approach to unveil the proteins responsible for PCOS

Polycystic ovary syndrome (PCOS) is a hormonal imbalance in women, which causes problems during menstrual cycle and in pregnancy that sometimes results in fatality. Though the genetics of PCOS is not fully understood, early diagnosis and treatment can prevent long-term effects. In this study, we have studied the proteins involved in PCOS and the structural aspects of the proteins that are taken into consideration using computational tools. The proteins involved are modeled using Modeller 9v14 and Ab-initio programs. All the 43 proteins responsible for PCOS were subjected to phylogenetic analysis to identify the relatedness of the proteins. Further, microarray data analysis of PCOS datasets was analyzed that was downloaded from GEO datasets to find the significant protein-coding genes responsible for PCOS, which is an addition to the reported protein-coding genes. Various statistical analyses were done using R programming to get an insight into the structural aspects of PCOS that can be used as drug targets to treat PCOS and other related reproductive diseases.

Association of LEPR Gln223Arg polymorphism with T2DM: A meta-analysis

A meta-analysis was conducted to evaluate the association of LEPR Gln223Arg polymorphism with type 2diabetes (T2DM). Sixteen individual studies with 7827 subjects were included into the meta-analysis. Current studies suggest that LEPR Gln223Arg polymorphism may not affect the susceptibility with type 2diabetes (T2DM).

Plasma Visfatin Levels in Adolescents with Polycystic Ovary Syndrome: A Prospective Case-Control Study

STUDY OBJECTIVE

We evaluated the plasma visfatin levels in hirsute female adolescents with polycystic ovary syndrome.

DESIGN, SETTING, AND PARTICIPANTS

This prospective case-control study included 87 female patients who were seen in our adolescence department. Demographic characteristics and hormonal and biochemical parameters were evaluated between patients with and without polycystic ovary syndrome. Next, we divided the patients with polycystic ovary syndrome into the following subgroups: overweight or obese (body mass index [BMI] ≥ 25 kg/m(2)) vs normal weight (BMI < 25 kg/m(2)) and hirsute vs nonhirsute.

RESULTS

There were statistically significant differences in the BMI, serum androgen levels, homeostasis model assessment-insulin resistance (HOMA-IR) levels, and insulin levels between patients with and without polycystic ovary syndrome (P < .05). The mean visfatin levels showed no statistically significant difference between these 2 groups (P > .05). The serum visfatin levels were similar between the 2 subgroups classified by BMI (P > .05). However, there were statistically significant differences in the total and free testosterone levels, 17-hydroxylase progesterone level, HOMA-IR level, and visfatin level between the 2 subgroups classified by hirsutism (P < .05). The plasma visfatin level was higher in hirsute PCOS than in nonhirsute PCOS patients.

CONCLUSION

Significantly higher visfatin levels were found in hirsute than in nonhirsute adolescents with PCOS. According to these results, plasma visfatin levels may be a useful marker in hirsute adolescents with PCOS.

Genome-wide association study identified new susceptibility loci for polycystic ovary syndrome

STUDY QUESTION

Are there any novel genetic markers of susceptibility to polycystic ovary syndrome (PCOS)?

SUMMARY ANSWER

We identified a novel susceptibility locus on chromosome 8q24.2 and several moderately associated loci for PCOS in Korean women.

WHAT IS KNOWN ALREADY

PCOS is a highly complex disorder with significant contributions from both genetic and environmental factors. Previous genome-wide association studies (GWAS) in the Han Chinese population identified several risk loci for PCOS. However, GWAS studies on PCOS remain very few. The aim of this study was to identify novel markers of susceptibility to PCOS through GWAS.

STUDY DESIGN, SIZE, DURATION

A two-stage GWAS was conducted. The initial discovery set for GWAS consisted of 976 PCOS cases and 946 controls. The second stage (replication study) included 249 PCOS cases and 778 controls.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients were diagnosed according to the Rotterdam criteria. Genomic DNAs were genotyped using the HumanOmni1-Quad v1 array. In the replication stage, the 21 most promising signals selected from the discovery stage were tested for their association with PCOS.

MAIN RESULTS AND THE ROLE OF CHANCE

One novel locus with genome-wide significance and seven moderately associated loci for PCOS were identified. The strongest association was on chromosome 8q24.2 (rs10505648, OR = 0.52, P = 5.46 × 10(-8)), and other association signals were located at 4q35.2, 16p13.3, 4p12, 3q26.33, 9q21.32, 11p13 and 1p22 (P = 5.72 × 10(-6)-6.43 × 10(-5)). The strongest signal was located upstream of KHDRBS3, which is associated with telomerase activity, and could drive PCOS and related phenotypes.

LIMITATIONS, REASONS FOR CAUTION

The limitation of our study is the modest sample size used in the replication cohort. The limited sample size may contribute to a lack of statistical power to detect an association or show a trend in severity.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings provide new insight into the genetics and biological pathways of PCOS and could contribute to the early diagnosis and prevention of metabolic and reproductive morbidities.

STUDY FUNDING/COMPETING INTERESTS

This work was supported in part by the grant from the Korea Centers for Disease Control and Prevention (2009-E00591-00). The work was also supported by the Ewha Global Top5 Grant 2013 of Ewha Womans University. None of the authors has any conflict of interest to declare.

Polymorphism in LEP and LEPR May Modify Leptin Levels and Represent Risk Factors for Thyroid Cancer

Purpose. To understand the role of polymorphisms in the LEP (rs7799039 and rs2167270) and LEPR (rs1137101 and rs1137100) genes in DTC susceptibility and their effect on leptin levels. Methods. We studied 153 patients with DTC and 234 controls through TaqMan SNP Genotyping and ELISA, comparing these data to the clinicopathological data of patients with DTC. Results. Patients with AA genotype of rs7799039 had higher levels of serum leptin (9.22 ± 0.98 ng/mL) than those with AG genotype (10.07 ± 0.60 ng/mL; P = 0.005). Individuals with AG genotype of rs2167270 also produced higher serum leptin levels (10.05 ± 0.59 ng/mL) than the subjects with GG genotype (9.52 ± 0.79 ng/mL; P < 0.05). A multivariate logistic regression adjusted for gender, age, and BMI showed that the AG genotype of rs7799039 was an independent risk for DTC (OR, 11.689; P = 0.0183; 95% CI, 1.516-90.119). Similarly, AG and GG genotypes of rs1137101 increased the susceptibility to DTC (OR, 3.747; P = 0.027; 95% CI, 1.161-12.092 and OR, 5.437; P = 0.013; 95% CI, 1.426-20.729). Conclusions. We demonstrated that rs7799039 and rs2167270 polymorphisms modify the serum leptin concentrations in patients with DTC. Furthermore, polymorphisms rs7799039 and rs1137101 increase the risk of DTC development, although they do not correlate with tumor aggressiveness.

Leptin as well as Free Leptin Receptor Is Associated with Polycystic Ovary Syndrome in Young Women

Background and Aim. Leptin has two forms in the circulation: free and bound forms. The soluble leptin receptor (sOB-R) circulates in the blood and can bind to leptin. The aim of this study is to assess the concentrations of the leptin and the sOB-R in PCOS and its relation to adiposity, insulin resistance, and androgens. Methods. A cross-sectional study included 78 female students aged 17-25 years. Fasting serum leptin and sOB-R concentrations were measured. The anthropometric variables and the hormonal profile such as insulin, female and male sex hormones, and prolactin were assessed. Results. In PCOS, leptin level (ng/ml) and free leptin index (FLI) increased significantly while sOB-R (ng/ml) significantly decreased compared to control subjects. In age-matched subjects, obese PCOS had increased leptin level in ng/ml (median level with interquartile levels) of 45.67 (41.98-48.04) and decreased sOB-R in ng/ml 11.47 (7.59-16.44) compared to lean PCOS 16.97 (10.60-45.55) for leptin and 16.62 (11.61-17.96) for sOB-R with p values 0.013 and 0.042, respectively. However, body mass index (BMI) is significantly correlated with leptin and s-OBR, while no significant correlations with parameters of insulin resistance were detected. Conclusion. PCOS is associated with hyperleptinemia and increased free leptin index. Decreased sOB-R could be a compensatory mechanism for the defective action of leptin.

Genes associated with metabolic syndrome predict disease-free survival in stage II colorectal cancer patients. A novel link between metabolic dysregulation and colorectal cancer

Studies have recently suggested that metabolic syndrome and its components increase the risk of colorectal cancer. Both diseases are increasing in most countries, and the genetic association between them has not been fully elucidated. The objective of this study was to assess the association between genetic risk factors of metabolic syndrome or related conditions (obesity, hyperlipidaemia, diabetes mellitus type 2) and clinical outcome in stage II colorectal cancer patients. Expression levels of several genes related to metabolic syndrome and associated alterations were analysed by real-time qPCR in two equivalent but independent sets of stage II colorectal cancer patients. Using logistic regression models and cross-validation analysis with all tumour samples, we developed a metabolic syndrome-related gene expression profile to predict clinical outcome in stage II colorectal cancer patients. The results showed that a gene expression profile constituted by genes previously related to metabolic syndrome was significantly associated with clinical outcome of stage II colorectal cancer patients. This metabolic profile was able to identify patients with a low risk and high risk of relapse. Its predictive value was validated using an independent set of stage II colorectal cancer patients. The identification of a set of genes related to metabolic syndrome that predict survival in intermediate-stage colorectal cancer patients allows delineation of a high-risk group that may benefit from adjuvant therapy and avoid the toxic and unnecessary chemotherapy in patients classified as low risk. Our results also confirm the linkage between metabolic disorder and colorectal cancer and suggest the potential for cancer prevention and/or treatment by targeting these genes.