Gonadotropin receptor variants are linked to cumulative live birth rate after in vitro fertilization.

PURPOSE: The objective was to investigate if the gonadotropin receptor variants N680S (N: asparagine, S: serine, rs6166) in the follicle-stimulating hormone receptor (FSHR) and N312S (rs2293275) in the luteinizing hormone/human chorionic gonadotropin receptor (LHCGR) predicted cumulative live birth rate after in vitro fertilization (IVF). METHODS: A total of 665 women were consecutively enrolled for IVF during the period 2007-2016. Inclusion criteria were < 40 years of age, body mass index < 30 kg/m2, non-smoking, regular menstruation cycle of 21-35 days, and bilateral ovaries. A blood sample was drawn for endocrine hormonal analysis and for DNA extraction with subsequent genotyping of the FSHR N680S and LHCGR N312S polymorphisms. Statistical analyses were done on all completed IVF cycles. RESULTS: Women homozygous for S in both receptors combined (4S) had significantly higher live birth rate compared to those with other receptor variants when combining the first three IVF cycles (OR = 2.00, 95% CI [1.02, 3.92], p = 0.043). Cumulatively higher chance of live birth rate, during all IVF cycles, was also evident (HR = 1.89, 95% CI [1.00, 3.57], p = 0.049). CONCLUSIONS: Gonadotropin receptor variants are promising candidates for the prediction of the possibility to have a baby to take home after IVF treatment.

Effect of the FSH receptor single nucleotide polymorphisms (FSHR 307/680) on the follicular fluid hormone profile and the granulosa cell gene expression in human small antral follicles.

The most pronounced effects of FSH signalling are potentially displayed in the follicle fluid, which acts as a reservoir for FSH-induced granulosa cell (GC) secreted hormones. This study investigates the effects of two common polymorphisms of FSHR, FSHR 307 (rs6165) and FSHR 680 (rs6166), by evaluating the hormone and gene expression profiles of human small antral follicles collected under physiological conditions in connection with fertility preservation. In total 69 women at various time during the menstrual cycle were included in this study. The intrafollicular hormone content of 179 follicular fluid samples and the gene expression levels of 85 GC samples were correlated to the genotype of both FSHR polymorphisms. The following parameters were evaluated: follicle diameter, levels of Anti-Müllerian hormone (AMH), progesterone, estradiol, testosterone and androstenedione and gene expression levels of FSHR, luteinizing hormone receptor (LHR), androgen receptor, aromatase cytochrome p450 (CYP19A1), AMH and AMH receptor II (AMHR2). There was 100% concordance between the FSHR 307 and the FSHR 680 genotypes: A/A (p.307Thr/Thr and p.680Asn/Asn), A/G (p.307Thr/Ala and p.680Asn/Ser) and G/G (p.307Ala/Ala and p.680Ser/Ser). Considering all follicles, compared with the other genotypes the G/G genotype was associated with significantly elevated gene expression levels for LHR, while AMHR2 gene expression levels were significantly reduced. In follicles 3-6 mm in diameter LHR gene expression was significantly increased, whereas AMH gene expression was significantly reduced for the G/G genotype. In follicles >6 mm, estradiol and CYP19A1 gene expression levels were significantly higher for the G/G genotype. In conclusion, significant changes were observed between the FSHR 307/680 polymorphisms in human small antral follicles collected under physiological FSH conditions.

Exposure to persistent organic pollutants and sperm sex chromosome ratio in men from the Faroe Islands.

People in the Arctic as well as fishermen on the polluted Swedish east coast are highly exposed to persistent organic pollutants (POPs). These compounds have been shown to affect the sperm Y:X chromosome ratio. In present study, the aim was to investigate whether polychlorinated biphenyl (PCB) congeners and 1,1,-dichloro-2,2,-bis(p-chlorophenyl)ethane (p,p'-DDE) influence sperm sex chromosome ratio in Faroese men, and whether these men differ regarding Y:X ratio compared to Greenland Inuit and Swedish fishermen. The study population (n=449) consisted of young men from the general population (n=276) as well as proven fertile men (n=173). The Y:X ratio was assessed by fluorescent in situ hybridization. Serum concentrations of POPs were measured using gas chromatography. Associations between POP concentrations and Y:X ratio were calculated using linear and non-linear regression models as well as trend analysis and pairwise comparison of exposure data categorized into quartiles. The selected POPs were associated with Y:X ratio in fertile Faroese men, but not in the total population; p,p'-DDE (95% CI for B=-0.005 to -0.001, p=0.005) and ΣPCB (95% CI for B=-0.005 to -0.001, p=0.012). Since p,p'-DDE and ΣPCB correlated significantly (r=0.927, p<0.001), the results involving the exposure variables can be regarded as a single finding. The Y:X ratio for the total Faroese population was 0.500±0.018, which was statistically significantly lower than in both Inuit and Swedish fishermen (0.512 for both). In conclusion, Faroese men presented with lower Y:X ratio than Greenland Inuit and Swedish fishermen. Although no direct health effects are expected due to the lower Faroese Y:X ratio, it could be indicative of adverse effects on the reproductive system.

Interactions between polymorphisms in the aryl hydrocarbon receptor signalling pathway and exposure to persistent organochlorine pollutants affect human semen quality.

Persistent organic pollutants (POPs) may affect male reproductive function. Many dioxin-like POPs exert their effects by activation of the aryl hydrocarbon receptor (AHR) signalling pathway. We analysed whether gene-environment interactions between polymorphisms in AHR (R554K) and AHR repressor (AHRR P185A) and serum levels of markers of POP exposure 1,1-bis-(4-chlorophenyl)-2,2-dichloroethene (p,p'-DDE) and 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) are associated with 21 parameters of male reproductive function in 581 proven-fertile European and Greenlandic men. In Greenlandic men, AHR variants significantly modified the association between serum levels of both p,p'-DDE and CB-153 and inhibin B levels, sperm chromatin integrity, and seminal zinc levels. In the total cohort, interactions between AHRR variants and serum levels of CB-153 were associated with sperm chromatin integrity and the expression of the pro-apoptotic marker protein Fas. The data indicate that susceptibility to adverse effects of POP exposure on male reproductive function is dependent on polymorphisms in genes involved in AHR signalling.

Inhibin B concentration is predictive for long-term azoospermia in men treated for testicular cancer.

Azoospermia is a serious potential side effect following treatment for testicular cancer (TC). Our purpose was to examine possible predictors of long-term azoospermia in TC survivors. Ejaculates and blood samples were obtained from 217 patients at post-orchidectomy but before further treatment (T0 ) and/or at one or more of the time points 6, 12, 24, 36-60 months after treatment (T6 , T12 , T24 , T36-60 ). All patients delivered ejaculates at T36-60 , of which 117 also had confirmed presence of spermatozoa in the ejaculate at T0 , enabling longitudinal analyses. Types of therapy, cryptorchidism and Inhibin B before and after treatment were evaluated in relation to risk of azoospermia at T36 . Inhibin B levels at T6 , T12 and T24 were predictors of azoospermia at T36 with cut-off levels at 49.7, 55.9 and 97.8 ng/L respectively (sensitivity 100%, specificity 57-78%). The frequency of azoospermia in all patients at T36-60 was 7.8% (95% CI 4.9-12%). As compared to surveillance patients, only those receiving >4 cycles of chemotherapy or ≥4 cycles of chemotherapy + radiotherapy (RT) had increased risk of long-term azoospermia (63% vs. 4.4% in the surveillance group; p = 0.0018). In conclusion, all patients with sperm production at post-orchidectomy but before further treatment and Inhibin B >56 ng/L 12 months after treatment had sperm production 3 years post-treatment. Eight per cent of TC survivors had azoospermia 3-5 years post-treatment, with highest risk in those receiving >4 cycles of chemotherapy or ≥4 cycles of chemotherapy in combination with RT.

Non-linear association between androgen receptor CAG and GGN repeat lengths and reproductive parameters in fertile European and Inuit men.

Recently the dogma that there is an inverse linear association between androgen receptor (AR) CAG and GGN polymorphisms and receptor activity has been challenged. We analysed the pattern of association between 21 male reproductive phenotypes and AR CAG/GGN repeat lengths in 557 proven-fertile men. A linear association was only found between sperm DNA fragmentation index (DFI) and CAG length, and between inhibin B and GGN length. Men with longer CAG then the reference (22-24), had higher oestradiol levels, whereas men with shorter CAG stretches had a higher DFI and a higher proportion of Fas-positive germ cells. Subjects with either short or long CAG had increased seminal levels of prostate-specific antigen and neutral α-glucosidase activity. Compared to men with the median GGN length of 23, those with shorter GGN repeats had higher levels of inhibin B, higher proportions of normal and progressive sperm, and a higher fraction of Fas-positive sperm, while men with longer GGN had higher oestradiol levels. These data indicate that at least for some markers of male reproductive function the association with CAG or GGN repeat length is curvilinear.

Response to treatment in patients with partial androgen insensitivity due to mutations in the DNA-binding domain of the androgen receptor.

The androgen insensitivity syndrome is a disorder caused by deficient function of the androgen receptor, characterized by varying degrees of undermasculinization in karyotypic males. We have identified four mutations in the androgen receptor gene, in the region encoding the DNA-binding domain of the protein. Two mutations, R607X and R615G, were found in patients with complete insensitivity to androgens, whereas the other two, S578T and A596T, were found in patients with partial insensitivity. The functional consequences of the three missense mutations were assayed in vitro after transient expression of the receptors in COS cells. All mutants showed normal androgen binding but abnormal abilities to stimulate transcription of an androgen-responsive reporter gene. R615G abolished transactivation whereas S578T and A596T were partially malfunctional. The function of A596T, but not of S578T, was normalized at high androgen concentrations in vitro, reflecting the in vivo situation. Thus, patients with specific mutations in the DNA-binding domain of the androgen receptor may benefit from androgen treatment.

Functional characterisation of mutations in the ligand-binding domain of the androgen receptor gene in patients with androgen insensitivity syndrome.

Five mutations in the ligand-binding domain of the androgen receptor gene were identified in patients with complete (A765T, C784Y, R831X and M895T) or partial (R840G) androgen insensitivity. A765T and R831X have been reported previously whereas the other three mutations are novel. Receptors carrying these mutations were transiently expressed in COS-1 cells, and androgen binding and capacity to transactivate an androgen-responsive reporter gene were assayed. C784Y led to abolished androgen binding and transactivating capacity, R840G and M895T showed reduced specific binding and partial transactivation. The in vitro functions of the R840G and M895T mutants were improved with supraphysiological concentrations of steroid.