Association of oestrogen receptor gene polymorphisms with outcome of ovarian stimulation in patients undergoing IVF

Association Between Follicle-Stimulating Hormone Receptor (FSHR) rs6166 and Estrogen Receptor 1 (ESR1) rs2234693 Polymorphisms and Polycystic Ovary Syndrome Risk, Phenotype, and Reproductive Outcomes in an Infertile Portuguese Population

INTRODUCTION

Polycystic ovary syndrome (PCOS) is a common endocrine disorder often leading to anovulatory infertility. PCOS pathophysiology is still unclear and several potential genetic susceptibility factors have been proposed. The effect of polymorphisms in two genesrelated to follicular recruitment and development, the follicle-stimulating hormone receptor (FSHR) and the estrogen receptor 1 (ESR1), have been studied in different populations with contradictory results.

AIMS

To evaluate the influence of FSHR rs6166 (c.2039A>G) and of ESR1 rs2234693 (Pvull c.453-397 T > C) polymorphisms on PCOS risk, phenotype, and response to controlled ovarian stimulation (COS).

MATERIALS AND METHODS

Genotyping of the FSHR rs6166 and the ESR1 rs2234693 polymorphisms was performed in PCOS women and a control group undergoing in vitro fertilization (IVF). Demographic, clinical, and biochemical data, genotype frequency, and IVF outcomes were compared between groups.

RESULTS

We evaluated 88 PCOS women and 80 controls. There was no significant difference in the genotype distribution of FSHR rs6166 polymorphism between PCOS women and controls (AA 31.8%/AS 48.9%/SS 19.3% in PCOS women vs AA 37.5%/AS 40.0%/SS 22.5% in controls; p = 0.522). The same was true for the ESR1 rs2234693 (CC 24.1%/CT 46.0%/TT 29.9% in PCOS women vs CC 18.8%/CT 48.8%/TT 32.5% in controls; p = 0.697). In PCOS women, we found higher follicle-stimulating hormone (FSH) levels on the third day of the menstrual cycle associated with the SS variant of the FSHR polymorphism (9.2 vs 6.2 ± 1.6 and 5.6 ± 1.6 mUI/mL; p = 0.011). We did not find other associations between the baseline hormonal parameters, antral follicle count, and response measures to COS with FSHR or ESR1 genotypes. We found, however, a need for higher cumulative doses of FSH for COS in patients with the SS variant of the FSHR rs6166 polymorphism (1860.5 ± 627.8 IU for SSvs 1498.1 ± 359.3 for AA and 1425.4 ± 474.8 for SA; p = 0.046 and p = 0.046).

CONCLUSION

Our data suggest that in the population, FSHR rs6166and ESR1 rs2234693 polymorphisms do not influence the risk of developing PCOS nor do they influence the patient's phenotype and IVF success. However, the SS variant of the FSHR rs6166 polymorphism may be associated with FSH resistance requiring higher FSH doses for COS.

The estrogen receptor polymorphisms and controlled ovulation hyperstimulation outcomes: a meta-analysis

Objective: Several studies evaluated the relationship between estrogen receptor (ER) polymorphisms and the outcomes of controlled ovulation hyperstimulation (COH). However, the results remained obscure. The objective of this study was to perform a meta-analysis to investigate the links between ER polymorphisms and COH outcomes.Methods: Eligible studies were identified from the following electronic databases: PubMed, Embase and the Chinese CNKI till Nov. 2021. The odds ratio (OR) and 95% confidence intervals (CIs) for dichotomous data and the weighted mean difference (WMD) with 95% confidence intervals (CIs) for continuous variables were used to calculate correlations between ER polymorphisms and COH outcomes. Based on the inclusion and exclusion criteria, a total of thirteen papers were eventually enrolled in the current meta-analysis.Results: The following were the key findings of this meta-analysis: (1) PvuII polymorphism had a significant relationship with IVF pregnancy outcome in all models, except the recessive model(CC VS TT: OR, 5.51, 95% CI, 1.13,26.84; CC + CT VS TT: OR, 3.73, 95% CI, 1.21,11.57; CT VS TT: OR, 3.19, 95% CI, 1.11,9.16;C VS T: OR, 2.19, 95% CI, 1.15, 4.19), with large or extreme heterogeneity; (2) XbaI polymorphism had a significant association with IVF risk in heterozygous and dominant models(AG VS GG: OR, 0.27, 95% CI, 0.12,0.61; AAAG VS GG: OR, 0.27, 95% CI, 0.12,0.59), with no heterogeneity; (3) (TA)n polymorphism was linked with IVF risk in the homozygous and recessive models(LL VS SS:OR = 3.74, 95%CI = 1.53,9.12;LL VS LS + SS:OR = 2.75, 95%CI = 1.18, 6.38), with no heterogeneity; (4) for Alul polymorphism and its association with POR risk, significant relationship was observed in the recessive model(AA VS AG + GG:OR = 2.27, 95%CI = 1.46, 3.54), with no heterogeneity;(5) PvuII T/C mutation did not predict the follicle number, oocyte number, ratio of follicles to oocytes and the risk of IVF;(6) for XbaI polymorphism and pregnancy outcome of IVF, no significant association was observed under all models; and (7) RsaI polymorphism does not increase the risk of POR under all models.Conclusion: In summary, our meta-analysis found evidence supporting that PvuII polymorphism may serve as a marker in predicting pregnancy rate in IVF-ET, XbaI and (TA)n polymorphisms may be related with infertility, and Alul polymorphism may predict the poor ovarian response to COH. More well-designed investigations are warranted to corroborate these findings.

Biochemical Characterization and Molecular Determination of Estrogen Receptor-α (ESR1 PvuII-rs2234693 T>C) and MiRNA-146a (rs2910164 C>G) Polymorphic Gene Variations and Their Association with the Risk of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is regarded as one of the most frequently encountered endocrine disorders and affects millions of young women worldwide, resulting in an array of complex metabolic alterations and reproductive failure. PCOS is a risk factor for diabetes mellitus, obstructive sleep apnea, obesity and depression in patients. Estrogen receptors (ESRs) are significant candidates in endocrine function and ovarian response in women. Moreover, microRNAs and long non-coding RNAs are emerging as principal mediators of gene expression and epigenetic pathways in various disease states. This study has characterized the clinical parameters in PCOS patients with comprehensive biochemical profiling compared to healthy controls and further examined the influence of allelic variations for estrogen receptor-α (ESR1 PvuII-rs2234693 T>C) and miRNA-146a (rs2910164 C>G) gene polymorphism on the risk of and susceptibility to PCOS. In this case-control study, we have used amplification refractory mutation specific (ARMS)-PCR to detect and determine the presence of these polymorphic variants in the study subjects. Our results demonstrated that most of the biochemical markers, which were analyzed in the study, show statistically significant alterations in PCOS patients, including fasting glucose, free insulin, HOMA-IR, LDL, HDL, cholesterol and hormones such as FSH, LH, testosterone and progesterone, which correlate with the established biochemical alterations in the disorder. Further, it is reported that for estrogen receptor-α (ESR1 PvuII-rs2234693 T>C), the frequency of the T allele (fT) was significantly higher among patients (0.64 vs. 0.44) compared to controls, while the frequency of the C allele (fC) was lower in patients (0.36 vs. 0.56) compared to controls. However, it was found that there was no association of an increased risk of PCOS with the ESR1 PvuII-rs2234693 C>T gene polymorphism. On the contrary, the study found strong association of miRNA-146a (rs2910164 C>G) gene polymorphism with an enhanced risk of PCOS. The frequency of the C allele (fC) was significantly higher among patients (0.52 vs. 0.36) compared to controls. The frequency of the G allele (fG) was found to be lower in patients (0.48 vs. 0.64) compared to controls. The codominant, dominant and recessive models display a statistically significant association of polymorphic variations with PCOS. Moreover, the G allele was associated strongly with PCOS susceptibility with an OR = 1.92 (95%) CI = (1.300−2.859), RR = 1.38 (1.130−1.691) p-value < 0.001.

Genetic polymorphisms of reproductive hormones and their receptors in assisted reproduction technology for patients with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies in women of childbearing, which is defined by the accumulation of multiple, small fluid-filled ovarian cysts without the selection of a single dominant follicle. Most PCOS phenotypes are characterized by the absence of spontaneous ovulation, resistance toward ovulation inductors, the production of a large immature oocytes number, and the high prevalence of ovarian hyperstimulation syndrome, resulting in reduced assisted reproductive technologies (ART) programs effectiveness. The review analyses current data about the relationship between polymorphism genotypes of KISS genes, follicle stimulating hormone (FSH), luteinizing hormone (LH), anti-Müllerian hormone (AMH) and their receptors genes, gonadotropin-releasing hormone (GnRH), estrogen, and progesterone receptors genes, the PCOS risk and the features of ovarian response to stimulation during ART cycles. The use of single nucleotide polymorphisms (SNPs) as prognostic markers of ART programs outcomes would provide a personalized approach to the drugs and doses choice for ovarian stimulation and significantly increase the chance of pregnancy.

Supplementation of maturation medium with CoQ10 enhances developmental competence of ovine oocytes through improvement of mitochondrial function

In vitro maturation (IVM) can impair the balance between antioxidant capacity and oxidative stress, and jeopardize embryo development by increasing oxidative stress, reducing energy metabolism, and causing improper meiotic segregation. Balancing the energy production and reduction of oxidative stress can be achieved by supplementation with coenzyme Q10 (CoQ10), an electron transporter in the mitochondrial inner membrane. To improve the in vitro production of ovine embryos, we studied the effect of CoQ10 supplementation during the maturation of sheep oocytes. A minimum of 100 cumulus-oocyte complexes (COCs) were matured in the presence of 15, 30, or 50 μM CoQ10 in three to five replicates; next, in vitro fertilization and culture in a subset of oocytes were done. Our data revealed that compared to control oocytes or other concentrations of CoQ10, supplementation with 30 µM CoQ10 resulted in a significant increase in blastocyst formation and hatching rates, improved the distribution, relative mass and potential membrane of mitochondria, decreased the levels of reactive oxygen species and glutathione and lessened the percentage of oocytes with misaligned chromosomes after spindle assembly. The relative expression levels of apoptosis markers CASPASE3 and BAX were significantly reduced in CoQ10-treated oocytes and cumulus cells whereas the relative expression level of GDF9, an oocyte-specific growth factor, significantly increased. In conclusion, supplementation with CoQ10 improves the quality of COCs and the subsequent developmental competence of the embryo.

Could polymorphisms of some hormonal receptor genes, involved in folliculogenesis help in predicting patient response to controlled ovarian stimulation?

PURPOSE

The aim of this study was to investigate whether single nucleotide polymorphisms (SNPs) in selected genes, responsible for hormonal regulation of folliculogenesis, are associated with response to controlled ovarian hyperstimulation (COH) and clinical characteristics of women enrolled in in vitro fertilization (IVF) programs.

METHODS

In a cross-sectional study, 60 (IVF) patients underwent COH by using gonadotropin-releasing hormone (GnRH) antagonist and recombinant follicle-stimulating hormone (rFSH) protocol. Patients were classified into three groups: poor-responders (according to Bologna criteria), normo-responders (≤ 15 oocytes), and hyper-responders (> 15 oocytes). Genotyping of SNPs AMH rs10407022, AMHR rs3741664, FSHR rs1394205 and rs6166, and ESR1 rs2234693 was performed using high-resolution melting analysis (HRMA). Basal FSH (bFSH), estradiol (E2), and anti-Müllerian hormone (AMH) were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Patients with GG genotype of FSHR rs1394205 had significantly lower AMH level (P = 0.016) and required higher rFSH dose per oocyte compared to women with AA or AG genotype (P = 0.036). We also found higher frequency of GG genotype of FSHR rs1394205 in poor- (76.5%) than in hyper-responders (37.5%, P = 0.002). Patients with AA genotype of FSHR rs6166 had higher level of measured bFSH compared to those with AG or GG genotypes (P = 0.043). Women with GG genotype of AMHR rs3741664 required higher rFSH dose in comparison with patients carrying genotypes AA or AG (P = 0.028).

CONCLUSIONS

The GG genotype at position rs1394205 is associated with poor ovarian response to COH. Patients with this genotype may require higher doses of rFSH for ovulation induction.

Nanosized titanium dioxide-induced premature ovarian failure is associated with abnormalities in serum parameters in female mice

Background

Exposure to titanium dioxide nanoparticles (TiO₂ NPs) that are widely used in food, medicine, sunscreen products and cosmetics is reported to cause ovarian damage and lower fertility in animals. However, the potential effects of TiO₂ NPs application on premature ovarian failure (POF) have rarely been evaluated to date.

Methods

In this study, female mice were continuously exposed to TiO₂ NPs at doses of 2.5, 5 or 10 mg/kg via gavage instillation for 30 days, and investigated the serum hormones and autoimmunity markers associated with POF.

Results

Exposure to TiO₂ NPs resulted in POF, reductions in the levels of estradiol, progesterone and inhibin B and increases in luteinizing hormone, follicle-stimulating hormone, follicle-stimulating hormone/luteinizing hormone ratio, anti-Müllerian hormone, thyroid-stimulating hormone, free triiodothyronine, free tetraiodothyronine, anti-nuclear antibody and anti-thyroid peroxidase antibody levels in serum.

Conclusion

Exposure to TiO₂ NPs induced POF triggered by alterations in hormones and autoimmunity markers. Our findings highlight the necessity for significant caution in handling and usage of TiO₂ NPs by female consumers.

ESR1 and ESR2 gene polymorphisms are associated with human reproduction outcomes in Brazilian women

Background

Important candidate genes involved in the ovarian response to exogenous FSH are the estrogen receptor genes (ESRs), since the effects of estrogens on follicle growth, maturation and oocyte release. It is known that some markers of ovarian stimulation can help to personalize the treatment, adjusting the dose of exogenous rFSH, thus preventing excessive wear of the patient. Inspired on this information we aimed to analyze four different polymorphisms in the estrogen receptor genes ESR1: rs2234693/T-397C (PvuII) and rs9340799/A-351G (Xbal) and ESR2: rs4986938/G1082A (RsaI) and rs1256049/A + 1730G (AluI), and their association with assisted reproduction outcomes in Brazilian women that underwent in vitro fertilization (IVF).

Methods

A cross-sectional study was performed involving 136 infertile women less than 39 years of age with normal ovarian reserve. Patients were divided according to the same COH protocol for statistical analysis. The Taqman assay was used for PvuII and XbaI of ESR1, and RsaI and AluI of ESR2 genotyping. Serum estradiol and FSH were measured by Elisa assay.

Results

The PvuII (ESR1) TT and RsaI (ESR2) GG genotypes were associated with a longer induction period and higher doses of medication (p < 0.03). The XbaI (ESR1) AA genotype was associated with better COH results, including a larger number of follicles, mature oocytes, embryos, and good quality embryos (p < 0.05). The AluI GG genotype showed an association with the Ovarian Hyperstimulation Syndrome (OHSS) (p = 0.03). According to the haplotype analysis of ER1 (PvuII/XbaI), we demonstrated that the CA combination increases by 0.68 the number of good quality embryos while the TG decreases it by 0.71 (p = 0.04).

Conclusion

ER polymorphisms have an association with the assisted reproduction outcomes in Brazilian women.

The follicular outcome after standard gonadotropin stimulation is associated with ERα and ERβ genotypes

The aim is to study the association of estrogen receptor α (ERα) and estrogen receptor β (ERβ) gene polymorphisms and diplotypes with ovarian response to follicle-stimulating hormone (FSH) stimulation and the hormone levels [FSH, luteinizing hormone (LH), E2] at the third day of the menstrual cycle. Three hundred women undergoing medically assisted reproduction and 300 women with at least one spontaneous pregnancy participated in the study. ERα PvuII and XbaI polymorphisms as well as ERβ AluI polymorphism were genotyped. The FSH, LH, and E2 levels were determined at the third day of the menstrual cycle, while the follicular size, the follicle, and oocyte numbers were recorded during oocyte retrieval. PvuII CC, XbaI GG, and AluI GG women were characterized by increased amounts of large follicles compared to PvuII TT, XbaI AA, and AluI AA women (p = 0.045, 0.01, and 0.033, respectively). The PvuII CC/XbaI GG diplotype was also significantly associated with higher large follicle numbers compared to the PvuII TT/XbaI AA diplotype (p = 0.024). However, no associations were observed between ER gene polymorphisms and the hormonal profile, the follicle/oocyte numbers, and the pregnancy rates. ERα and ERβ genetic variants were associated with ovarian response to standard gonadotropin stimulation of women undergoing in-vitro fertilization affecting mainly the follicular growth.

Gene polymorphisms in female reproduction

This chapter presents an overview of the gene polymorphisms underlying the functions of ovarian receptors and their clinical implications in the female fecundity. A selection of genetic studies revealing significant associations between receptor polymorphisms, gene mutations, and some pathological conditions (i.e., female infertility, premature ovarian failure, polycystic ovary syndrome, endometriosis) are reviewed.

Association study of estrogen receptor alpha gene polymorphisms with spontaneous abortion: is this a possible reason for unexplained spontaneous abortion?

Estrogen plays a crucial role in fetal and placental development through estrogen receptors. Association of estrogen receptor alpha gene (ESR1) polymorphisms with spontaneous abortion has been shown in some studies. Our main goal was to study the potential association of spontaneous abortion with the ESR1 gene variations (PvuII and XbaI) in fetal tissue. Totally, 161 samples were recruited including 80 samples of formalin-fixed paraffin-embedded fetal tissue from spontaneous abortion and 81 samples of normal term placental tissue. The restriction fragment length polymorphism (RFLP) method was performed for genotyping the rs2234693 (A/G XbaI) and rs9340799 (T/C PvuII) single nucleotide polymorphisms located in intron 1 of ESR1. The results have been confirmed by DNA sequencing analysis. The different genotypes distribution was detected in two study groups. Haplotype analysis indicated that ppxx is protective genotype against spontaneous abortion (P = 0.01). In conclusion, the potential role of ESR1 genetic variation in spontaneous abortion might be valuable in high-risk subjects, and that needs to be confirmed with future studies.

Predictive value of hormonal parameters for live birth in women with unexplained infertility and male infertility

BACKGROUND

Infertile women might get pregnant sometime after fertility treatment, but today, there is no prediction model on who will eventually have children. The objective of the present study was to characterize hormone levels in an arbitrary menstrual cycle in women with unexplained infertility and male infertility, and to determine the predictive value for long-term possibility of live birth.

METHODS

In this cross-sectional study, with 71 infertile women with diagnosis unexplained infertility and male infertility, blood samples were obtained during the proliferative and secretory phases of an arbitrary menstrual cycle. Serum concentrations of FSH, LH, AMH, inhibin B, estradiol, progesterone, PRL and TSH were determined. The predictive value of ovulation and hormonal analysis was determined by identifying the proportion of women with at least one live birth. Mann Whitney U test, chi2 test and Spearman's correlation were used for statistical analysis. A value of p < 0.05 was considered statistically significant.

RESULTS

There were no differences in hormone values and live birth rates between women with unexplained infertility and male infertility. The best sole predictors of live birth were age of the women, followed by ovulatory cycle, defined as serum progesterone concentration of greater than or equal to 32 nmol/L, and a serum TSH concentration of less than or equal to 2.5 mIU/L. Combining the age with the ovulatory cycle and serum TSH less than or equal to 2.5 mIU/L or serum AMH greater than or equal to 10 pmol/L the predictive value was close to 90%.

CONCLUSIONS

Age in combination with the presence of an ovulatory cycle and serum TSH or serum AMH is predictive for long-term live birth. The advantage of serum AMH compared with serum TSH is the very little variation throughout the menstrual cycle, which makes it a useful tool in infertility diagnosis.

Do estrogen receptor alpha polymorphisms have any impact on the outcome in an ART program?

PURPOSE

To investigate two of the most studied estrogen receptor alpha polymorphisms (PvuII and XbaI) in combination, in order to evaluate their impact on an ART program outcome.

METHODS

203 normally ovulating women who underwent IVF or ICSI treatment were genotyped for PvuII and XbaI polymorphisms in ESR1 intron 1 using Real-Time PCR. The relationship between the presence of polymorphic alleles and the ovulation induction parameters and outcome was examined.

RESULTS

Women were grouped according to the number of polymorphic alleles they carried in two groups (0-2 versus 3-4 polymorphic alleles). The presence of 3 or more polymorphic alleles was associated with significantly lower E2 levels on the day of hCG administration and a significantly lower rate of good quality embryos.

CONCLUSION

There is an association between ESR1 polymorphisms and some ART parameters such as the level of E2 on the day of hCG administration and the quality of the embryos. These results underline the importance of ESR1 as a candidate gene for the prediction of ovarian response to IVF/ICSI protocols. Future research work concerning several more genes is necessary for a better evaluation of patients before entering an IVF/ICSI program.

Genetic polymorphisms influence the ovarian response to rFSH stimulation in patients undergoing in vitro fertilization programs with ICSI

INTRODUCTION

Obtaining an adequate number of high-quality oocytes is a major challenge in controlled ovarian hyperstimulation (COH). To date, a range of hormonal and clinical parameters have been used to optimize COH but none have significant predictive value. This variability could be due to the genetic predispositions of single-nucleotide polymorphisms (SNPs). Here, we assessed the individual and combined impacts of thirteen SNPs that reportedly influence the outcome of in vitro fertilisation (IVF) on the ovarian response to rFSH stimulation for patients undergoing intracytoplasmic sperm injection program (ICSI).

RESULTS

Univariate analysis revealed that only FSHR, ESR2 and p53 SNPs influenced the number of mature oocytes. The association was statistically significant for FSHR (p=0.0047) and ESR2 (0.0017) in the overall study population and for FSHR (p=0.0009) and p53 (p=0.0048) in subgroup that was more homogeneous in terms of clinical variables. After Bonferroni correction and a multivariate analysis, only the differences for FSHR and ESR2 polymorphisms were still statistically significant. In a multilocus analysis, only the FSHR and AMH SNP combination significantly influenced oocyte numbers in both population (p<0.01).

DISCUSSION

We confirmed the impact of FSHR and ESR2 polymorphisms on the IVF outcome. Furthermore, we showed for the first time that a p53 polymorphism (which is already known to impact embryo implantation) could influence the ovarian response. However, given that this result lost its statistical significance after multivariate analysis, more data are needed to draw firm conclusions. Only the FSHR and AMH polymorphism combination appears to influence mature oocyte numbers but this finding also needs to be confirmed.

MATERIALS AND METHODS

A 13 gene polymorphisms: FSHR(Asn680Ser), p53(Arg72Pro), AMH(Ile49Ser), ESR2(+1730G>A), ESR1(-397T>C), BMP15(-9C>G), MTHFR1(677C>T), MTHFR2(1298A>C), HLA-G(-725C>G), VEGF(+405G>C), TNFα(-308A>G), AMHR(-482 A>G), PAI-1 (4 G/5 G), multiplex PCR assay was designed to genotype women undergoing ICSI program. We analyzed the overall study population (n=427) and a subgroup with homogeneous characteristics (n=112).

How contemporary human reproductive behaviors influence the role of fertility-related genes: the example of the p53 gene

Studies on human fertility genes have identified numerous risk/protective alleles involved in the occurrence of reproductive system diseases causing infertility or subfertility. Investigations we carried out in populations at natural fertility seem to suggest that the clinical relevance that some fertility genes are now acquiring depends on their interaction with contemporary reproductive behaviors (birth control, delayed childbearing, and spacing birth order, among others). In recent years, a new physiological role in human fertility regulation has emerged for the tumor- suppressor p53 gene (P53), and the P53 Arg72Pro polymorphism has been associated with recurrent implantation failure in humans. To lend support to our previous observations, we examined the impact of Arg72Pro polymorphism on fertility in two samples of Italian women not selected for impaired fertility but collected from populations with different (premodern and modern) reproductive behaviors. Among the women at near-natural fertility (n = 98), the P53 genotypes were not associated with different reproductive efficiency, whereas among those with modern reproductive behaviors (n = 68), the P53 genotypes were associated with different mean numbers of children [Pro/Pro = 0.75<Pro/Arg = 1.7<Arg/Arg = 2, (p = 0.056)] and a significant negative relationship between the number of children and P53 Pro allele frequencies (p = 0.028) was observed. These results are consistent with those of clinical studies reporting an association between the P53 Pro allele and recurrent implantation failure. By combining these findings with previous ones, we suggest here that some common variants of fertility genes may have become "detrimental" following exposure to modern reproductive patterns and might therefore be associated with reduced reproductive success. Set within an evolutionary framework, this change could lead to the selection of a set of gene variants fitter to current reproductive behaviors as the shift to later child-bearing age in developed countries.

Influence of follicle-stimulating hormone receptor (FSHR) Ser680Asn polymorphism on ovarian function and in-vitro fertilization outcome: a meta-analysis

BACKGROUND

A common follicle-stimulating hormone (FSH) receptor (or FSHR) polymorphism Ser680Asn (rs6166) was found to be associated with altered ovarian response in women undergoing in-vitro fertilization. To further investigate such an association, a meta-analysis was conducted.

METHODS

A PubMed literature search was conducted to identify all cohort studies investigating such a relationship. The following parameters-basal FSH levels, total FSH doses, oocytes retrieved, and pregnancy rates-were used to evaluate the ovarian function, its response to exogenous FSH and in-vitro fertilization and intracytoplasmic sperm injection outcome.

RESULTS

A total of 1421 cases were collected from eight studies. Of them, a significantly lower basal FSH level was observed in patients harboring Asn/Asn (NN) genotype than those carrying the Ser/Ser (SS) genotype both in Asian (WMD: -2.57 mIU/ml, 95% CI: -2.96 to -2.19, P<0.0001) and Caucasian retrospective groups (WMD: -1.86 mIU/ml, 95%CI: -2.07 to -1.66, P<0.0001) with no heterogeneity. Moreover, carriers of the SS tended to require greater FSH doses than NN (WMD: -268.82IU, 95% CI: -561.28 to 23.63, P=0.07). Other parameters, such as oocytes retrieved and pregnancy rate, were not significantly different between the groups.

CONCLUSION

Carriers of the SS variant have slightly higher basal FSH levels, tending to require higher doses of exogenous FSH for stimulation.

Polymorphisms in ESR1, ESR2 and HSD17B1 genes are associated with fertility status in endometriosis

OBJECTIVE

To investigate whether polymorphisms in genes involved in biosynthesis and signalling of sex steroids influence susceptibility to endometriosis and to infertility associated with it.

MATERIALS AND METHODS

Patients with endometriosis (n = 150) and fertile controls (n = 199) were genotyped for polymorphisms in oestrogen receptor genes ESR1 (rs2234693 - T/C single nucleotide polymorphism (SNP), dinucleotide (TA)(n) repeat) and ESR2 (dinucleotide (CA)(n) repeat), progesterone receptor gene PGR (rs10895068 - G/A SNP, 306-bp Alu-insertion), 17β-hydroxysteroid dehydrogenase type 1 gene HSD17B1 (rs605059 - A/G SNP), and aromatase gene CYP19A1 (rs10046 - C/T SNP, (TTTA)(n) tetranucleotide repeat, 3-bp TCT insertion/deletion polymorphism).

RESULTS

The HSD17B1 A/G SNP A allele increased overall endometriosis risk and the risk of stage I-II disease, while ESR1 longer (TA)(n) repeats only correlated with susceptibility to stage I-II endometriosis. When considering patients' fertility status, HSD17B1 A/G SNP A allele and ESR1 longer (TA)(n) repeats were associated with endometriosis accompanied by infertility, while ESR2 shorter (CA)(n) repeats were linked with endometriosis without infertility. Other polymorphisms were distributed similarly among patients and controls.

CONCLUSIONS

Genetic variants in ESR1, ESR2, and HSD17B1 genes could modify susceptibility to endometriosis and might influence the fertility status in endometriosis patients.

Alteration of ERβ gene RsaI polymorphism may contribute to reduced fertilization rate and embryonic developmental competence

This paper aims to determine the possible role of estrogen receptor-β (ERβ) gene RsaI polymorphism on sperm fertility and early embryonic development in humans. Three groups of Chinese men were recruited: in vitro fertilization (IVF) group, including 374 couples who underwent conventional IVF; intracytoplasmic sperm injection (ICSI) group, including 294 couples who underwent an ICSI procedure using ejaculated sperm; and azoospermic group, consisting of 197 couples who underwent ICSI using either testis or epididymis sperm. RsaI polymorphism in the ERβ gene was detected by polymerase chain reaction (PCR)-restriction fragment length polymorphism technique; fertilization and high-quality embryo rates were evaluated for each group. In each group, no significant differences were found in the overall rates of fertilization and high-quality embryos among GG, AG and AA genotypes. However, the proportion of cycles possessing a satisfactory high-quality embryo rate with the AA genotype was significantly lower than that in the wild-type GG genotype from each group. These results demonstrated that sperm possessing the ERβ RsaI A genotype may have reduced fertilization ability and decreased early embryonic developmental potential, which could directly or indirectly contribute to the low fertilization rate and early embryonic developmental arrest in some cases.

Evaluation of in vitro fertilization parameters and estrogen receptor alpha gene polymorphisms for women with unexplained infertility

PURPOSE

Association of ESR1 gene PvuII, XbaI and (TA)n microsatellite polymorphisms and woman infertility was evaluated.

METHODS

Infertile(n = 104) and fertile(n = 107) women were included in this study. We performed polymerase chain reaction-restriction fragment-length polymorphism analysis for detecting ESR1 polymorphisms.

RESULT(S)

PvuII and XbaI polymorphisms confered risk for infertility in a simple dominant manner in which a significant relationship was observed between infertile and control women. Infertile women had fewer(<18) short repeat alleles in promotor region. ESR1 genotypes were compared concerning maturation, fertilization, pregnancy rates and embryo quality. Although no difference was found in terms of pregnancy rates, maturation and fertilization rates were significantly smaller in pp and xx genotypes. Also, pp genotypes had significantly lower number of good quality embryos. Long TA repeat in promotor was found to be associated with low fertilization rate.

CONCLUSION(S)

Polymorphisms at the ESR1 gene are associated with infertility in this Turkish infertile women population.

Phenotypic and pharmacogenetic aspects of ovulation induction in WHO II anovulatory women

Because of an enormous increase in pharmacogenetic and -genomic knowledge, an era of predicting drug response on the basis of one's genome is drawing close to reality. Anovulation is the most common cause of infertility, and outcomes of treatment are often unpredictable. This review aims to summarise in what way genetic variability might modify effects of drug-metabolising enzymes, transporters and receptors, thereby altering response to drugs used in ovulation induction.

The role of steroid hormones in ART

Steroid hormones hold a major role in female fertility and their proper utilisation and monitoring in modern assisted reproduction protocols is important. Oocyte maturation and endometrial receptivity are the two major factors that appear to be related to a successful outcome in Assisted Reproductive Technology (ART). Many reports suggest that oocyte immaturity accounts for a considerable loss of efficiency in ART, mainly due to the poor quality of the obtained embryos and their inability to develop normally. Oestrogen appears to exert its effects on the cytoplasmic maturation of the oocyte, while progesterone has been shown to accelerate meiotic resumption. Moreover, ovarian stimulation appears to affect the normal luteal function and shifts in the window of implantation as a response to hormonal supplementation have also been observed. The ethical limitations in conducting in vivo studies of human implantation, have led to an indirect hormonal- and morphologic-oriented assessment of endometrial receptivity. The two main protocols of luteal support involve either progesterone supplementation or hCG administration, whereas the combined supplementation with oestradiol remains controversial. This brief review aims to summarize the current knowledge on steroidal actions during the above processes and to address their potential use in the improvement of current ART protocols.

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.

Estrogen Receptor Alpha and Beta Gene Polymorphisms Are Not Risk Factors for Recurrent Miscarriage in a Brazilian Population

The aim of this study was to determine the prevalence of alpha (ESR1: c.454-397T>C and c.454-351A>G) and beta (ESR2: 1082G>A and 1730G>A) estrogen receptor gene polymorphisms in 2 Brazilian ethnic groups (Caucasian, African Brazilian) and to investigate their association with recurrent miscarriage (RM) in 75 women with a history of 3 or more consecutive pregnancy losses and 139 controls with at least 2 live births and no history of pregnancy loss. Polymerase chain reaction and restriction fragment length polymorphism were used to identify gene polymorphisms. Coagulation methods were used to measure protein C, protein S, and fibrinogen, and a chromogenic method was used for antithrombin quantification. Significantly higher prevalences of 1082G>A and 1730G>A polymorphisms were seen in African Brazilian and Caucasian controls, respectively. There was no association between RM and ESR polymorphisms. There was a difference in the genotype prevalence in the c.454-39T>C polymorphism between RM and control Caucasians, but this finding was not associated with an increased risk of miscarriage. There was no synergistic or additive effect between ESR polymorphisms and thrombophilia in RM patients. A difference in the prevalence of ESR polymorphisms was observed, according to ethnic origin. ESR polymorphisms could not be considered a risk factor for RM.

Controlled ovarian hyperstimulation pharmacogenetics: a simplified model to genetically dissect estrogen-related diseases

The application of pharmacogenetics and pharmacogenomics to assisted reproductive techniques will help clinicians to improve the efficacy of hormone treatments that are being routinely applied during assisted reproductive technique protocols. Genetic markers involving controlled ovarian hyperstimulation pharmacogenetics are being isolated within follicle-stimulating hormone and estrogen receptor signaling pathways using the candidate gene approach. Furthermore, the information obtained during controlled ovarian hyperstimulation pharmacogenetics studies could be applied to other estrogen-related diseases, such as osteoporosis, breast cancer, essential hypertension and many other diseases related to estrogen production or its mechanism of action. The theory that estrogen-related diseases may share some risk factors with controlled ovarian hyperstimulation efficacy, and side effects linked to genetic markers, is discussed.

Potential use of biomarkers for analyzing interpopulation and cross-cultural variability in reproductive aging

OBJECTIVE

The aims of this study were (1) to document the extent of variability in physiological aspects of reproductive aging; (2) to outline those areas where more work is needed to expand our knowledge of this variability; (3) to outline available biomarkers that can be used to measure aspects of reproductive aging, such as ovarian reserve and declining hormone levels; and (4) to note potential problems with the use of these biomarkers in cross-cultural settings.

DESIGN

Literature review of English and French publications using PubMed with no date restrictions.

RESULTS

Substantial variability exists in both cultural and physiological aspects of reproductive aging and menopause. However, the extent of variability across populations for many areas of reproductive aging needs better documentation as well as explanation of sources of this variability. Several biomarkers exist for use in cross-cultural research, including ovarian characteristics such as ovarian volume, ovarian reserve, follicular development, and atresia, and levels of hormones such as follicle-stimulating hormone, inhibin B, and anti-mullerian hormone.

CONCLUSION

We urge that further work be undertaken to evaluate and describe variability in physiological aspects of reproductive aging in cross-cultural settings. Some problems exist in the use of biomarkers to record this variability, particularly in remote settings with few logistical resources.

Methylenetetrahydrofolate reductase (MTHFR) is associated with ovarian follicular activity

OBJECTIVE

Polymorphisms in the MTHFR gene have been associated with decreased cell division and apoptosis. This finding led us to evaluate whether MTHFR polymorphisms were associated with follicular growth within the ovary. More specifically, we investigated the effect of the two common polymorphisms C677T and A1298C in our population of women undergoing ovarian stimulation.

DESIGN

Prospective cohort study.

SETTING

Academic medical center.

PATIENT(S)

Two hundred twenty-three women undergoing ovarian stimulation.

INTERVENTION(S)

The DNA from patients was genotyped at the MTHFR C677T and A1298C polymorphisms.

MAIN OUTCOME MEASURE(S)

Day 3 FSH, E(2), antral follicle count, amount of gonadotropin used, the number of follicles >13 mm, E(2) on the day of hCG administration, and oocyte number.

RESULT(S)

Women with the variant MTHFR 1298 C allele had significantly higher basal FSH levels, and after ovarian stimulation, produced fewer follicles >13 mm, had lower E(2) levels on the day of hCG administration, and required more ampules of gonadotropin hormone during treatment. Women with the variant MTHFR 677 T allele demonstrated no significant differences.

CONCLUSION(S)

The MTHFR A1298C polymorphism, but not the C677T polymorphism, is associated with higher basal FSH levels and may be a determinant of response to ovarian stimulation. These findings make a compelling case for the MTHFR A1298C polymorphism to modulate folliculogenesis.

Estrogen receptor alpha polymorphisms and fertility in populations with different reproductive patterns

The estrogen receptor (ER) plays an important role in mediating estrogen action on target tissues. ER-alpha, the most abundant, is found in all human reproductive tissues and studies on alpha-ER knockout mice have highlighted its role in reproduction. ER-alpha gene (ESR1) polymorphisms have been associated with a variety of disorders including human infertility. In this study, we examined the association of ESR1 PvuII and XbaI polymorphisms with fertility in two populations with different reproductive patterns and precisely in a sample of healthy Italian men and women (n=178) and in a sample of healthy African-Ecuadorian women (n=57). ESR1 xx and ppxx genotypes among the Italian men were found to be associated with an above-median number of children (P=0.01 and P=0.004, respectively). ESR1 pp genotype among the Italian women showed a tendency to be associated with a lower number of abortions (P=0.04), whereas ESR1 pp and ppxx genotypes among African-Ecuadorian women were associated with a higher number of children (P=0.02 and P=0.03, respectively). These results are consistent with previous observations indicating a role of ESR1 genotypes in human infertility and give insight into the complex interactions between genotypes and reproductive behaviours in human populations.

Allelic estrogen receptor 1 (ESR1) gene variants predict the outcome of ovarian stimulation in in vitro fertilization

The outcome of in vitro fertilization (IVF) depends substantially on the effectiveness of controlled ovarian hyperstimulation (COH) induced by administration of follicle-stimulating hormone (FSH). In COH, endogenously produced estrogens extend the action of FSH in stimulating folliculogenesis. We determined the associations between genetic variations in estrogen receptor ESR1 and ESR2 genes and etiology of female infertility, and analysed the influence of these variations on COH outcome-the quantity and quality of oocytes retrieved. ESR1 PvuII T/C (rs2234693) and XbaI A/G (rs9340799) single-nucleotide polymorphisms (SNPs) and (TA)n microsatellite polymorphism, as well as ESR2 RsaI G/A (rs1256049) SNP and (CA)n microsatellite polymorphism were genotyped in 159 IVF patients. The ovarian response to FSH was diminished in patients with endometriosis when compared to tubal factor infertility. ESR1 PvuII and XbaI as well as ESR2 RsaI SNPs were associated with the microsatellite length of the respective genes. Shorter ESR1 (TA)n was linked with a higher risk for unexplained infertility, whereas longer ESR1 (TA)n associated with PvuII*C allele were predictive of a better COH, but not clinical pregnancy outcome in an age-independent manner. These data suggest the variations in ESR1 gene, in addition to the age of a woman, may predict the COH outcome in IVF.

Obligatory roles for follicle-stimulating hormone (FSH), estradiol and androgens in the induction of small polyfollicular ovarian cysts in hypophysectomized immature rats

Immature hypophysectomized (HYPOXD) rats develop large, polyfollicular ovarian cysts in response to unabated, combined stimulation by subovulatory doses of human chorionic gonadotropin (hCG) and highly purified ovine follicle-stimulating hormone (FSH). Further, circulating amounts of androstenedione (A4) and estradiol (E2), but not testosterone or dihydrotestosterone (DHT), change in parallel with the development of these cysts. To determine the potential roles of either A4 or E2 at the level of the ovary in the induction of ovarian cysts, pellets containing either (1) cholesterol (placebo; controls); (2) A4; or (3) E2 were administered subcutaneously (sc) to immature HYPOXD rats. Some of these animals also received either twice-daily sc injections of 1 IU hCG, or daily s.c. injections of 2 microg FSH, for 13 days. Ovaries and sera were harvested from all treatment groups on the morning of day 14 of the combined-hormone treatment schedule. As expected, ovaries from HYPOXD rats treated with placebo, A4, or E2 pellets (with or without hCG) failed to display antral follicles. Ovaries from HYPOXD rats treated with FSH and a placebo pellet displayed polyfollicular, atretic, small antral follicles with unstimulated thecal shells. In addition, the ovarian stromal-interstitial tissue had an unstimulated appearance. In contrast, ovaries from HYPOXD rats treated with FSH plus either A4 or E2 implants displayed stimulated stromal-interstitial tissue as well as small follicular cysts and precysts with stimulated thecal shells. The number of cysts and precysts observed in the largest ovarian cross-sections for animals treated with FSH + A4 (17.0 +/- 3.0) was less than that observed in the largest ovarian cross-sections for HYPOXD rats treated with FSH + E2 (40.2 +/- 10.1; p < 0.05). To determine if the development of ovarian cysts in response to FSH + A4 was due, at least in part, to the metabolism of A4 to E2, HYPOXD rats were treated with either (1) placebo pellets; (2) pellets containing dihydrotestosterone (DHT) which cannot be metabolized to estrogen; (3) E2 pellets plus DHT pellets (E2 + DHT); (4) FSH + DHT; or (5) FSH + E2 + DHT. The largest ovarian cross-sections from FSH + DHT-treated HYPOXD rats displayed 18.3 +/- 4.1 small follicles with a mean diameter of approximately 0.437 mm which possessed few granulosa cells. The thecal and stromal-interstitial tissues in these ovaries were unstimulated, which indicates that these small degenerating follicles were atretic rather than cystic. In contrast, the largest ovarian cross-sections from FSH + E2 + DHT-treated HYPOXD rats displayed 51.6 +/- 2.4 cysts with stimulated thecal shells and a mean diameter of approximately 0.634 mm. Further, these cysts were arranged in a "string of pearls" pattern and the ovarian stromal-interstitial tissue possessed a stimulated appearance. These data demonstrate a direct, unambiguous role at the level of the ovary for unabated tonic stimulation by FSH plus estrogen in the development of small polyfollicular cysts in HYPOXD rats. Further, the data also indicate that, at least in HYPOXD rats, combined, tonic stimulation by FSH plus estrogen and androgen is sufficient for the development of small, polyfollicular ovarian cysts in a "string of pearls" pattern. These observations are in distinct contrast to our previous observations that tonic stimulation by FSH + hCG results in the induction of large ovarian cysts in HYPOXD rats and provide tantalizing new insights regarding the potential importance of specific hormones at the level of the ovary in the induction of specific types of cystic follicles.

The Duarte (N314D) variant in the GALT gene has no effect on in vitro fertilization outcome

We assessed the effect of the Duarte (N314D) variant in the GALT gene on in vitro fertilization outcome measures. Our data do not definitely exclude variants in the GALT gene as factors influencing outcome, but the lack of suggestive evidence makes it difficult to justify a larger, more definitive study.

Pharmacogenetics in ovarian stimulation - current concepts and future options

Tailoring ovarian stimulation to the individual patient can be challenging because the ovarian response varies substantially between patients. Pharmacogenetics has emerged as a new area of research to improve the balance between desired and undesired actions of drugs, based upon the genetic predisposition of the individual patient. Clinical studies have demonstrated that the p.N680S polymorphism of the FSH-receptor gene determines the ovarian response to FSH stimulation in patients undergoing IVF. In homozygous Ser(680)/Ser(680) type women, the FSH receptor appears to be more resistant to FSH action even in normal menstrual cycles. Therefore, genotyping of patients scheduled for ovarian stimulation could be an attractive tool to individualize FSH dosing according to genetic differences in ovarian sensitivity. More clinical studies are warranted to investigate the usefulness of genotyping for the p.N680S polymorphism as a routine diagnostic test before ovarian stimulation.

Association of estrogen receptor alpha polymorphisms with breast cancer risk in older Caucasian women

Estrogens exert their effect on the breast through the estrogen receptor. We prospectively investigated breast cancer risk associated with 2 polymorphic sites in the estrogen receptor alpha gene (ESR1). A total of 4,248 Caucasian women from the Study of Osteoporotic Fractures were genotyped for the -401 T/C and -354 A/G polymorphisms in ESR1. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the associations between genotypes and breast cancer. During a mean follow-up of 12.4 years, 252 (5.9%) women developed breast cancer. The HR (95% CI) for breast cancer were 0.928 (0.708, 1.22) and 0.834 (0.538, 1.29) for the -354 A/G and A/A genotypes, respectively. Interactions with -354 variant were observed for smoking (HR = 1.52 and 1.56 for A/G and A/A smokers, respectively; HR = 0.74 and 0.60 for A/G and A/A non-smokers, respectively; interaction p = 0.03) and walking (HR = 0.75 and 1.15 for A/G and A/A walkers, respectively; HR = 0.18 and 0.49 for A/G and A/A non-walkers, respectively; interaction p = 0.01). There were no differences in the HR for the -401 T/C genotypes. An interaction between parity and carriage of the T allele was found (HR = 0.60 vs. 1.12 for nulliparous vs. parous women; interaction p = 0.03). ESR1 polymorphisms in combination with lifestyle factors may be associated with breast cancer risk in older Caucasian women.

Pharmacogenetics of controlled ovarian hyperstimulation

Controlled ovarian hyperstimulation (COH) is a routine treatment employed in most assisted reproductive techniques (ARTs). The existence of genetic factors involved in COH has been suspected. The main challenge for clinicians involved in ART is COH cycle cancellation, which usually occurs due to two opposing situations. On the one hand, there is the presence of a poor response during COH treatment, and on the other there is the presentation of a side effect related to gonadotropin hypersensitivity (ovarian hyperstimulation syndrome [OHSS]). Evidence for an association between single nucleotide polymorphisms and COH outcome has been obtained during the last decade. The genetic dissection of both extreme phenotypes of COH will be the main objective of this review. The development of predictive panels useful for the clinical management of COH is currently underway, and will improve the clinical management of patients undergoing ART.

Factors influencing response to ovarian stimulation

Ovarian stimulation is an integral part of assisted reproduction treatments. Ovarian response to gonadotrophin treatment, besides other factors, determines the outcome of treatment, as the number and quality of oocytes retrieved are related to the chance of achieving a pregnancy. A number of factors have been identified that might predict ovarian response, such as age of the patient and antral follicle count. In addition, it has been shown that genetic factors such as the patient's FSH-receptor genotype also determine individual response to FSH treatment. Besides patient-related factors, the choice of drugs for ovarian stimulation plays a significant role. Until recently, biopotency of gonadotrophin preparations was tested by an in-vivo bioassay with an intrinsic variability up to 20%. Due to a superior manufacturing technique, follitropin alpha can now be filled by mass. This allows assessment of FSH with a precise SE-HPLC assay and variability of the FSH content between production lots has now been estimated at 1.6%. Results of recent studies indicate that treatment with follitropin alpha filled by mass results in consistent ovarian response, fewer treatment days and fewer cancelled cycles. This is an important step towards further minimizing drug-related variability of ovarian response to FSH treatment.

Human controlled ovarian hyperstimulation outcome is a polygenic trait

This study aimed to evaluate the association between follicle-stimulating hormone (FSH) hormone efficacy and FSHR, CYP19, ESR1 and ESR2 genes using single nucleotide polymorphism analyses. One hundred and seventy women with conserved ovarian function undergoing controlled ovarian stimulation (COS) with daily exogenous recombinant FSH administration. Women were categorized as poor responders to FSH (three or less ovarian follicles observed at the end of cycle) or normal responders (more than three follicles). The outcome is the number of normal/poor responders as defined by the number of follicles obtained during COS. The DNA markers studied are located in genes related to the FSH mechanism of action (FSH receptor, CYP19 aromatase and oestrogen receptors alpha and beta genes). We conducted an association study between the COS outcome and selected DNA markers using two-point and multi-locus genetic association studies. Genotype pattern tracking in extreme phenotypes and multi-locus analysis using Sumstat and PM algorithms provided significant evidences of genetic interaction between FSHR, ESR1 and ESR2 markers in relation to COS outcome (P = 0.0015). Our results support the hypothesis that a discrete set of genes, related to the FSH hormone mechanism of action, controls the ovarian response to FSH in humans. An oligogenic model including specific FSHR, ESR1 and ESR2 genotype patterns may partially explain the poor response to FSH hormone during controlled ovarian stimulation treatments. The existence of genetic heterogeneity is also suspected.

Role of follicle-stimulating hormone receptor Ser680Asn polymorphism in the efficacy of follicle-stimulating hormone

OBJECTIVE

To evaluate the association between FSH efficacy and FSHR alleles.

DESIGN

Retrospective study.

SETTING

University-based fertility unit and a private center for biomedical research.

PATIENT(S)

One hundred two women with ovarian function who were undergoing controlled ovarian stimulation (COS). Women were categorized as poor responders (< or =3 ovarian follicles at the end of the cycle) or normal responders (>3 follicles).

INTERVENTION(S)

Daily administration of exogenous FSH.

MAIN OUTCOME MEASURE(S)

Number of good or poor responders.

RESULT(S)

The allele frequency and genotype distribution of the Ser680Asn marker differed significantly between groups. Cycle cancellations were increased (21%) among women who were homozygous for Ser680 compared with Ser/Asn and Asn/Asn patients, and 36% of poor-responders were homozygous for Ser680.

CONCLUSION(S)

The results support a role for FSHR gene in COS outcome. However, the weight of this factor is probably low. The Ser680 allele may act in concert with other environmental and genetic factors that contribute to FSH efficacy.

Wild-type estrogen receptor (ERbeta1) and the splice variant (ERbetacx/beta2) are both expressed within the human endometrium throughout the normal menstrual cycle

Estrogen action is mediated via two subtypes of the estrogen receptor (ER), usually referred to as ERalpha and ERbeta. We have previously compared the spatial and temporal expressions of ERalpha and ERbeta proteins in human endometrium and reported that endothelial cells exclusively express ERbeta. In the present study we have extended our investigations to compare the pattern of expression of wild-type (ERbeta1) and a newly identified ERbeta variant isoform (ERbetacx/beta2) that lacks the ability to bind steroids. mRNAs encoding both ERbeta1 and ERbetacx/beta2 receptors were identified in human endometrial extracts by RT-PCR. Quantitative TaqMan R-TPCR demonstrated that levels of total mRNAs were increased significantly premenstrually as circulating progesterone levels declined. ERbeta1 and ERbetacx/beta2 proteins were identified within multiple cell types within the endometrium using isotype-specific monoclonal antibodies; immunoexpression of ERbetacx/beta2 appeared less intense than that of ERbeta1 in endometrial glandular epithelium and endothelial cells. Immunoexpression of ERbeta1 appeared unchanged throughout the menstrual cycle. In contrast, levels of ERbetacx/beta2-specific immunoreactivity were specifically reduced in gland cells within the functional layer, but not in those of the basal layer, in the midsecretory phase. It is possible that coexpression of ERbetacx/beta2 in cells containing ERbeta1 and/or ERalpha may modulate the effects of estrogens on the endometrium.

Association of oestrogen receptor alpha polymorphisms and androgen receptor CAG trinucleotide repeats with male infertility: a study in 109 Greek infertile men

This study was performed to examine the contribution of genetic polymorphism of oestrogen and androgen receptor (AR) genes in male infertility. We have studied in total 173 Greek men, 109 infertile patients and 64 controls (group A). Patients were divided in to three subgroups: group B (n=29) with idiopathic moderate oligospermia, group C (n=42) with azoospermia or idiopathic severe oligospermia and group D (n=38) with azoospermia or oligospermia of various known aetiologies. All patients and controls were genotyped for two polymorphisms of the oestrogen receptor alpha (ERalpha) gene and also for the (CAG)n repeat length polymorphism of the X-linked androgen receptor (AR)gene. The control group had statistically significant difference from group C regarding the XbaI polymorphism of ERalpha gene. Despite the fact that we did not observe any statistically significant differences in the mean and range of the CAG repeat number, the frequency of the higher repeats of the nucleotide repeat sequence (CAG)n of the AR gene was 2-4 times higher in groups B and C compared with the control group A. Our results indicate that both ERalpha and AR gene play significant role in male fertility. It is possible that a synergy may exist between unfavourable genotypes of these two genes in male infertility.

Implications of the Human Genome Project for obstetrics and gynecology

The initial sequencing of the human genome should be regarded as a milestone in a road that stretches years into the future; the full ramifications of the Human Genome Project are still only being theorized. Researchers will benefit from the catalog of human genes in studies of the genetics of disease susceptibility and the cell biology of gene interactions. Clinicians will increasingly offer genetic or biochemical testing to identify those at highest risk for a number of diseases. Drug discovery will eventually follow newly possible studies of gene expression and protein function. However the Human Genome Project eventually shapes medicine, it is certain that physicians, particularly obstetricians and gynecologists, will need to be well versed in the scientific and ethical issues involved, inasmuch as we will likely be at the center of the most heated debates.

Genotype distribution of estrogen receptor-alpha gene polymorphisms in Italian women with surgical uterine leiomyomas

OBJECTIVE

To explore a possible association between estrogen receptor-alpha (ER-alpha) gene polymorphisms and development of uterine leiomyomas.

DESIGN

Case-control study.

SETTING

University teaching hospital.

PATIENT(S)

119 women with clinically and surgically diagnosed uterine leiomyomas.

INTERVENTION(S)

Therapeutic hysterectomy.

MAIN OUTCOME MEASURE(S)

Frequency and distribution of ER-alpha gene polymorphisms.

RESULT(S)

No statistically significant differences between controls and patients in the allele frequency and genotype distribution were found when Pvu II and Xba I restriction polymorphism sites were analyzed separately. When the two ER-alpha gene polymorphisms were analyzed in combination, five major genotypes were recognized in controls or patients; the frequency differed slightly but not significantly between groups.

CONCLUSION(S)

The Pvu II and Xba I polymorphisms in the ER-alpha gene do not produce different risks of developing uterine leiomyomas.

Oestrogen receptor-alpha gene polymorphism is associated with endometriosis, adenomyosis and leiomyomata

Endometriosis, adenomyosis and leiomyomata develop in women of reproductive age and regress after menopause or ovariectomy, suggesting that they grow in an oestrogen-dependent fashion. We investigated whether polymorphism in the oestrogen receptor-alpha (ERalpha) gene is related to oestrogen-dependent benign uterine disease. A total of 203 women with regular menstrual cycles underwent laparotomy or laparoscopy and were diagnosed histologically with endometriosis, adenomyosis and/or leiomyomata. Patients with cervical carcinoma in situ, tubal occlusion or adhesion but no other gynaecological disease were considered to be disease-free. A total of 179 women undergoing annual health examination were grouped as reference population. The distribution of PVUII genotypes (PP, Pp, and pp) of the ERalpha gene was different between each pair of the four groups of endometriosis, adenomyosis/leiomyomata, disease-free, and reference population (P = 0.022-0.0005), except between the former two groups. The PP genotype was less frequent in the groups of endometriosis (P = 0.0002) and adenomyosis/leiomyomata (P = 0.002) as compared to that in the disease-free group. In the endometriosis group, there was no difference in the distribution of PVUII genotypes due to complicating diseases (adenomyosis and/or leiomyomata) or severity of the clinical stages. These results suggest that the PVUII polymorphism of the ERalpha gene is associated with the risk for endometriosis, adenomyosis, and leiomyomata.