Birutė Žilaitienė

Study in 1790 Baltic men: FSHR Asn680Ser polymorphism affects total testes volume

Follicle‐stimulating hormone receptor (FSHR) contains two common linked polymorphisms, Thr307Ala (rs6165) and Asn680Ser (rs6166), shown to modulate ovarian function in women. The effect on male fertility and reproductive parameters has been inconclusive. We studied FSHR Asn680Ser polymorphism in a large study group (n = 1790) from the Baltic countries. The population‐based Baltic male cohort (Estonians, Latvians, Lithuanians; n = 1052) and Estonian oligo‐/azoospermic (sperm concentration <20 × 106/mL) idiopathic infertile patients (n = 738) were genotyped for the FSHR Asn680Ser using PCR‐RFLP. Genetic associations were tested using linear regression under additive model and results were combined in meta‐analysis. No statistical difference was detected in allelic distribution of the FSHR Asn680Ser between the Baltic cohort and Estonian male infertility group. A consistent significant association was detected between the FSHR Ser680 allele and lower total testes volume in both, the Baltic cohort (p = 0.010, effect = −1.16 mL) and Estonian idiopathic infertility group (p = 0.007, effect = −1.77 mL). In meta‐analysis, the statistical significance was enhanced (p = 0.000066, effect = −1.40 mL). Meta‐analysis supported further associations with moderate effect between the FSHR Ser680 variant and higher serum FSH (p = 0.072), lower Inhibin B (p = 0.037) and total testosterone (p = 0.034). No statistically significant associations were identified with serum LH and estradiol, and sperm parameters. In conclusion, the study in 1790 Baltic men shows statistically highly significant association of the FSHR Asn680Ser with total testes volume and supportive association with serum reproductive hormone levels indicative to the functional effect of the alternative FSHR variants on male reproductive physiology.

Reproductive Physiology in Young Men Is Cumulatively Affected by FSH-Action Modulating Genetic Variants: FSHR -29G/A and c.2039 A/G, FSHB -211G/T

Follicle-Stimulating Hormone Receptor (FSHR) -29G/A polymorphism (rs1394205) was reported to modulate gene expression and reproductive parameters in women, but data in men is limited. We aimed to bring evidence to the effect of FSHR -29G/A variants in men. In Baltic young male cohort (n = 982; Estonians, Latvians, Lithuanians; aged 20.2±2.0 years), the FSHR -29 A-allele was significantly associated with higher serum FSH (linear regression: effect 0.27 IU/L; P = 0.0019, resistant to Bonferroni correction for multiple testing) and showed a non-significant trend for association with higher LH (0.19 IU/L) and total testosterone (0.93 nmol/L), but reduced Inhibin B (−7.84 pg/mL) and total testes volume (effect −1.00 mL). Next, we extended the study and tested the effect of FSHR gene haplotypes determined by the allelic combination of FSHR -29G/A and a well-studied variant c.2039 A/G (Asn680Ser, exon 10). Among the FSHR -29A/2039G haplotype carriers (A-Ser; haplotype-based linear regression), this genetic effect was enhanced for FSH (effect 0.40 IU/L), Inhibin B (−16.57 pg/mL) and total testes volume (−2.34 mL). Finally, we estimated the total contribution of three known FSH-action modulating SNPs (FSHB -211G/T; FSHR -29G/A, c.2039 A/G) to phenotypic variance in reproductive parameters among young men. The major FSH-action modulating SNPs explained together 2.3%, 1.4%, 1.0 and 1.1% of the measured variance in serum FSH, Inhibin B, testosterone and total testes volume, respectively. In contrast to the young male cohort, neither FSHR -29G/A nor FSHR haplotypes appeared to systematically modulate the reproductive physiology of oligozoospermic idiopathic infertile patients (n = 641, Estonians; aged 31.5±6.0 years). In summary, this is the first study showing the significant effect of FSHR -29G/A on male serum FSH level. To account for the genetic effect of known common polymorphisms modulating FSH-action, we suggest haplotype-based analysis of FSHR SNPs (FSHR -29G/A, c.2039 A/G) in combination with FSHB -211G/T testing.

The number of CAG and GGN triplet repeats in the Androgen Receptor gene exert combinatorial effect on hormonal and sperm parameters in young men

Androgen receptor (AR) is a transcription factor that is activated upon binding to testosterone (T) and is implicated in regulating the expression of reproduction‐related genes. The human AR gene (Xq11‐12) spans 186,588 bp and eight exons. N‐terminal transactivation domain of the encoded AR protein harbours two polymorphic stretches of identical amino acids, a polyglutamine tract (encoded by 8‐37 CAG‐repeats) and a polyglycine tract (encoded by 10‐30 GGN‐repeats). We set forward to analyse independent and combinatory effects of the length of these repetitive tracts on male reproductive hormones, testicular and sperm parameters in a population‐based cohort of Baltic young men (n = 974; aged 20.1 ± 2.1 years). We designed an assay to amplify and detect simultaneously the variants of both polymorphic repeats. The study revealed that elongated AR CAG tract was associated with lower FSH (linear regression: p = 0.0002, effect per repeat −0.056 IU/L). As a novel finding, the carriers of GGN‐stretch with ≥24 repeats showed a trend for decreased sperm concentration (p = 0.027). Although neither of the variants exhibited an isolated effect on circulating T, their allelic combinations modulated serum T levels, as well as sperm concentration. The lowest T was measured for men carrying the AR gene with long CAG (n ≥ 25) and short GGN (n ≤ 21) repeat tracts (mean 18.8 vs. 25.5–28.6 nmol/L for the other AR variants, p = 0.017). The lowest sperm concentration was detected among individuals with both elongated repetitive stretches (CAG, n ≥ 25 and GGN, n ≥ 24; mean 49.0 vs. 68.4–72.1 mill/mL for the other variants; p = 0.00059). The innovative study design enabled to clearly demonstrate a combinatory impact of CAG and GGN repeat lengths at male reproductive parameters. As AR regulates transcription of over 900 genes in many tissues and organs, the combinatory effects of these common repeat‐length variants on male physiology in the wider context and across lifetime are still to be assessed.

‘Carriers of V-LH among 1593 Baltic men have significantly higher serum LH’

Luteinizing hormone (LH) is a pituitary heterodimeric glycoprotein essential in male and female reproduction. Its functional polymorphic variant (V‐LH) is determined by two missense mutations (rs1800447, A/G, Trp8Arg; rs34349826, A/G, Ile15Thr) in the LH β‐subunit encoding gene (LHB; 19q13.3; 1111 bp; 3 exons). Among women, V‐LH has been associated with higher circulating LH and reduced fertility, but the knowledge of its effect on male reproductive parameters has been inconclusive. The objective of this study was to assess the effect of V‐LH on hormonal, seminal and testicular parameters in the Baltic young men cohort (n = 986; age: 20.1 ± 2.1 years) and Estonian idiopathic infertility patients (n = 607; 35.1 ± 5.9 years). V‐LH was detected by genotyping of the underlying DNA polymorphisms using PCR‐RFLP combined with resequencing of a random subset of subjects. Genetic associations were tested using linear regression under additive model and results were combined in meta‐analysis. No significant difference was detected between young men and infertility patients for the V‐LH allele frequency (11.0 vs. 9.3%, respectively). V‐LH was associated with higher serum LH in both, the young men cohort (p = 0.022, allelic effect = 0.26 IU/L) and the idiopathic infertility group (p = 0.008, effect = 0.59 IU/L). In meta‐analysis, the statistical significance was enhanced (p = 0.0007, resistant to Bonferroni correction for multiple testing; effect = 0.33 IU/L). The detected significant association of V‐LH with increased serum LH remained unchanged after additional adjustment for the SNPs previously demonstrated to affect LH levels (FSHB ‐211G/T, FSHR Asn680Ser, FSHR ‐29A/G). Additionally, a suggestive trend for association with reduced testicular volume was observed among young men, and with lower serum FSH among infertility patients. The V‐LH carrier status did not affect sperm parameters and other circulating reproductive hormones. For the first time, we show a conclusive contribution of V‐LH to the natural variance in male serum LH levels. Its downstream clinical consequences are still to be learned.

The effect of a drospirenone-containing combined oral contraceptive on female sexual function: a prospective randomised study

Abstract Objectives: The study investigated the effects on female sexual function of a progestogen-containing combined oral contraceptives (COCs) with an antiandrogenic profile taken in a continuous regimen. Methods: In this prospective randomised single-institution study, 80 healthy women with a monogamous partner and an active sexual life were randomised into two groups for a period of 3 months. Women in the exposed group (n = 40) took a COCs containing 30 μg ethinylestradiol (EE) and 3 mg drospirenone (DRSP) in a 21/7 regimen. Women in the control group (n = 40) used either a barrier contraceptive method (BCM) or a natural family planning method (NFPM). Participants were asked to complete a set of validated questionnaires to assess sociodemographic variables and measure Female Sexual Function Index (FSFI). Results: The total FSFI score (p < 0.0001), as well as the desire (p = 0.04) and arousal (p = 0.03) scores, were significantly lower in the COCs group after 3 months of hormonal contraceptive use compared with baseline. Women using BCM or NFPM showed an improvement in total FSFI score (p = 0.02). Hormonal contraception with DRSP increased the likelihood of worse sexual function in the desire (odds ratio [OR] 2.47; 95% confidence interval [CI] 1.22, 4.98; p = 0.01) and arousal domains (OR 2.85; 95%CI 1.34, 5.93; p = 0.005) and in total FSFI score (OR 2.01; 95%CI 1.45, 2.79; p < 0.001). The results remained statistically significant even after adjustment for smoking status. Conclusions: The study found evidence that women taking a combined EE/DRSP COCs for 3 months may have a worsening of sexual function as measured by FSFI.