Nectaria Xita

Severity of cardiovascular disease in postmenopausal women: associations with common estrogen receptor α polymorphic variants

OBJECTIVE Impaired estrogen action is a risk factor for coronary artery disease (CAD). Associations of CAD with estrogen receptor alpha (ER alpha) polymorphisms, which may influence sensitivity to estrogen, have been reported for men; the data concerning women are not conclusive. We investigated the association of common ER alpha polymorphisms with the severity of CAD and with metabolic and reproductive factors in postmenopausal women undergoing coronary angiography. METHODS ER alpha polymorphisms at positions c.454-397 T>C (PvuII) and c.454-351 A>G (XbaI) were studied in 157 women (age 45-88 years). The severity of CAD was assessed by the number of arteries with >50% stenosis in the angiography. RESULTS There was a significant association between the TT, TC, and CC genotypes (PvuII) and the severity of CAD (P=0.008); similar results were obtained for the XbaI polymorphism (P=0.021). These associations were independent of other risk factors for CAD. Women homozygous for the C allele had significantly higher triglyceride and insulin levels; they belonged more frequently to the group with a low number of births (n</=1; P=0.014, Fishers exact). CONCLUSIONS Common ER alpha polymorphisms may influence the severity of CAD in women undergoing coronary angiography, reflecting lifetime exposure to estrogen. Similar associations have been reported for men with CAD. These polymorphisms should probably be taken into account when associations with estrogenic actions are examined.

Genetic variants of sex hormone-binding globulin and their biological consequences.

Several hormonal and metabolic factors have been found to influence the production of sex hormone-binding globulin (SHBG). In addition, twin studies have suggested that genetic factors may also contribute to variation in SHBG levels. Given the clinical significance of SHBG in regulating bioavailable sex steroid hormones, a number of studies examined the potential association between polymorphisms of SHBG gene and serum SHBG levels as well as their possible contribution in the pathogenesis of common diseases. Thus, polymorphisms of SHBG, altering either the production or the metabolism of the protein, may represent part of the genetic background of sex steroid hormone activity in humans. There is considerable heterogeneity in the results of these studies indicating the multiplicity of the factors influencing SHBG variation. However, the weight of evidence suggests that some common genetic variants of SHBG may influence SHBG levels and in part contribute to the phenotypic expression of human diseases.

Evidence for association of sex hormone-binding globulin and androgen receptor genes with semen quality

The roles of androgen receptor AR(CAG)n gene polymorphisms and sex hormone‐binding globulin SHBG(TAAAA)n gene polymorphisms on semen quality were studied. One hundred fourteen men were included in the study: 85 with normal sperm count and 29 oligospermic. The genotype analysis, on DNA extracted from spermatozoa, revealed five SHBG(TAAAA)n alleles with 6–10 repeats and 18 AR(CAG)n alleles with 12–32 repeats. The SHBG allelic distribution showed that in men with normal sperm count and motility, those with short SHBG alleles had higher sperm concentration than men with long SHBG alleles (P = 0.039). As concerns AR(CAG)n polymorphisms, men with short AR alleles had lower sperm motility compared to those with long AR alleles (P < 0.001) in both total study population and normal sperm count men. The synergistic effect analysis of the two polymorphisms revealed an association between sperm motility (P = 0.036), because of the effect of AR(CAG)n polymorphism on sperm motility. In conclusion, long AR alleles were found to be associated with higher sperm motility, while short SHBG alleles were associated with higher sperm concentration, supporting the significance of these genes in spermatogenesis and semen quality.

Estrogen Receptor α and β Polymorphisms Are Associated With Semen Quality

The role of estrogen receptor alpha (ER alpha) and estrogen receptor beta (ER beta) gene polymorphisms on semen quality is the aim of our study. One hundred fourteen men were examined in the In Vitro Fertilization Unit of Ioannina Medical School, and it was found that 85 men had normal sperm count and 29 were oligozoospermic. The genotype analysis, on DNA extracted from spermatozoa, revealed that in men with oligozoospermia (sperm concentration <20 x 10(6) spermatozoa/mL), those with ER alpha 397T/C and 397C/C genotypes had higher sperm motility whereas those with 397T/T genotype had lower sperm motility (P = .003). In addition, men with ER alpha 351A/A genotype had lower sperm motility compared with 351A/G and 351 G/G genotypes (P = .013). Furthermore, normal-sperm-count men with ER alpha 397T/T genotype had higher sperm concentration compared with 397T/C and 397C/C genotypes (P = .016), whereas men with ER alpha 351A/A genotype had higher sperm concentration than those with 351A/G and 351G/G genotypes (P = .05). In contrast, no significant associations were found between ER beta (1082G-->A and 1730A-->G) polymorphisms and sperm concentration or motility. In conclusion, ER alpha polymorphisms were found to be associated with sperm motility and concentration. supporting the significance of this gene in spermatogenesis and semen quality.

The synergistic effect of sex hormone-binding globulin and aromatase genes on polycystic ovary syndrome phenotype.

OBJECTIVE Experimental evidence suggests that fetal exposure to androgen excess may program the development of polycystic ovary syndrome (PCOS) in utero. The aim of this study was to examine whether the sex hormone binding globulin (SHBG)(TAAAA)n and the cytochrome P450, family 19 (CYP19)(TTTA)n polymorphisms, known to influence sex hormone-binding globulin (SHBG) levels and aromatase activity respectively, play a synergistic role in the development of PCOS. DESIGN AND METHODS We studied 180 women with PCOS and 160 healthy women of reproductive age. The body mass index (BMI) was recorded and the hormonal profile determined from the third to fifth day of menstrual cycle. DNA was extracted from blood leucocytes and the SHBG(TAAAA)n and CYP19(TTTA)n polymorphisms were genotyped. RESULTS Genotype analysis revealed 6 SHBG(TAAAA)n alleles with 6-11 repeats and 6 CYP19(TTTA)n alleles with 7-12 repeats. Women were subdivided into four groups: those with short SHBG (< or = 8 TAAAA repeats) and CYP19 alleles (< or = 9 TTTA repeats), those with short SHBG-long CYP19 alleles, those with long SHBG-short CYP19 alleles, and those with long SHBG and CYP19 alleles. Women with PCOS tended to have at greater frequency, long SHBG-short CYP19 alleles compared with controls (57.3 vs 42.4%, P=0.07). Importantly, PCOS women with long SHBG-short CYP19 alleles had the lowest SHBG levels (P=0.02) and the highest total testosterone (P=0.008), free androgen index (P=0.002), DHEAS (P=0.02), and testosterone/estradiol ratio (P=0.03), compared with those with other genotypes. This association was independent of age, BMI, and insulin resistance indexes. CONCLUSION We speculate that the SHBG and CYP19 genes may have a synergistic role in the developmental programming of PCOS, by affecting androgen bioavailability and aromatization respectively.

The association of aromatase (CYP19) gene variants with sperm concentration and motility

The irreversible transformation of androgens into oestrogens is catalysed by cytochrome P450 aromatase. In the present study, we explored the contribution of the (TTTA)(n) polymorphism in the aromatase gene (CYP19) to sperm concentration and motility. Ninety normozoospermic and 60 oligospermic men were examined during infertility examinations. DNA was extracted from spermatozoa, and the CYP19 (TTTA)(n) polymorphism was genotyped by PCR. Genotype analysis revealed six CYP19 (TTTA)(n) alleles with 7-12 repeats. The allelic distribution of the CYP19 (TTTA)(n) polymorphism differed between normozoospermic and oligospermic men (P<0.01). Oligospermic men less frequently had long CYP19 alleles than did normozoospermic men (25 and 37.8%, respectively; P<0.02). The higher frequency of short CYP19 alleles in oligospermic men compared to normozoospermic men (43.3 and 28.3%, respectively; P<0.01) was primarily due to the distribution of the CYP19 (TTTA)(7) allele. The CYP19 (TTTA)(7) allele was associated with lower sperm concentration in normozoospermic men (P<0.01) and in the total study population (P<0.01); it was also associated with lower sperm motility in normozoospermic men (P<0.05) and in the total study population (P<0.01). In conclusion, the CYP19 (TTTA)(7) allele probably impairs aromatase activity, which in turn alters aromatase and oestrogen levels in the testis, leading to decreased sperm concentration and motility. These findings support the significance of cytochrome P450 aromatase in human spermatogenesis and consequently in semen quality.

The Pro12Ala polymorphism of the PPAR-γ gene is not associated with the polycystic ovary syndrome

OBJECTIVEInsulin resistance is a key factor in the pathogenesis of polycystic ovary syndrome (PCOS). Peroxisome proliferator-activated-receptor-γ (PPAR-γ) has been implicated in insulin resistance and adiposity. The aim of the study was to investigate the possible involvement of the Pro12Ala polymorphism of the PPAR-γ gene in the pathogenesis of PCOS.DESIGNWe studied 180 women with PCOS and 140 healthy controls. Body mass index (BMI) was recorded. Blood samples were drawn after overnight fasting and serum glucose, insulin, lipid and hormonal profiles were determined. The fasting glucose/insulin ratio and HOMA index were calculated. Moreover, 100 women with PCOS underwent a 75g oral glucose tolerance test and the area under the curve for insulin and glucose was estimated. DNA was extracted from peripheral blood leucocytes and the Pro12Ala polymorphism was genotyped.RESULTSThe PPAR-γ genotypes were found to be in the Hardy-Weinberg equilibrium in both study groups. No difference was found in the distribution of the Pro12Ala polymorphism between PCOS and controls. Insulin resistance indices and lipid and hormonal profile were not different among the various genotypes of the Pro12Ala polymorphism.CONCLUSIONSThe Pro12Ala polymorphism of the PPAR-γ gene is not involved in the pathogenesis or the phenotypic expression of PCOS.

The importance of the (TAAAA)n alleles at the SHBG gene promoter for the severity of coronary artery disease in postmenopausal women.

Objective: Androgen may be detrimental in the development of coronary artery disease (CAD) in women. We investigated possible associations between the (TAAAA)n polymorphism of sex hormone-binding globulin (SHBG) gene promoter, which influences transcriptional efficiency of the SHBG gene and the severity of CAD in women. Design: In this prospective clinical study, 146 postmenopausal women (46-88 y) undergoing coronary angiography were studied. CAD severity, history of angina and myocardial infarction, and reproductive history were recorded and hormonal parameters measured. According to the number of SHBG gene promoter repeat polymorphisms, participants were classified into short (seven or fewer), medium length (eight), and long repeat (nine or more) allele groups. Results: Significant CAD was more prevalent in the long repeat allele carrier group: 65% of the participants with three vessels with severe stenosis belonged to the long repeat allele group, whereas only 37% of participants with mild CAD belonged to this group (P = 0.01). A history of angina and prevalence of hyperlipidemia was more frequent in the long repeat allele group (P < 0.05). Calculated free testosterone levels were higher in the long repeat allele groups (P < 0.05), whereas SHBG levels tended to be lower (P = 0.06). SHBG levels correlated inversely with body mass index and waist circumference (P < 0.05). Conclusions: Longer (TAAAA)n repeats in the SHBG gene promoter are associated with more severe CAD in women undergoing coronary angiography, a finding not previously reported. This association may reflect the lifelong tissue exposure to higher free androgens and supports the adverse cardiovascular effect of androgenic exposure in this highly selected group of women.

Semen quality is influenced by androgen receptor and aromatase gene synergism

STUDY QUESTION Does synergism between AR(CAG)(n) and CYP19(TTTA)(n) polymorphisms influence the quality of sperm? SUMMARY ANSWER AR(CAG)(n) and CYP19(TTTA)(n) polymorphisms had a synergistic effect on sperm concentration and motility. WHAT IS KNOWN ALREADY Androgens exert their action in the testicular tissue by binding to androgen receptor (AR), while their action is mediated by the aromatase P450 enzyme (CYP19). AR(CAG)(n) alleles are associated with sperm motility and CYP19(TTTA)(n) allelic variants have implications for sperm concentration and motility. STUDY DESIGN, SIZE, DURATION Two hundred oligozoospermic and 250 normozoospermic men who presented for infertility investigation were examined during a period of 2 years. PARTICIPANTS/MATERIALS, SETTING, METHODS Conventional semen analysis was performed. DNA was extracted from spermatozoa and both polymorphisms were genotyped by polymerase chain reaction. Serum hormone levels were determined. MAIN RESULTS AND THE ROLE OF CHANCE Six combined genotypes were identified between the 18 AR(CAG)(n) alleles with 12-32 repeats and the 6 CYP19(TTTA)(n) alleles with 7-12 repeats. A gradual reduction in the sperm concentration (10(6)/ml) and motility (%) from long AR allele-non-CYP19(TTTA)(7) allele carriers to long AR allele-CYP19(TTTA)(7) homozygotes and from short AR allele-non-CYP19(TTTA)(7) carriers to short AR allele-CYP19(TTTA)(7) homozygotes was observed in normozoospermic men (means ± SD; concentration: 93 ± 53.1 versus 65 ± 48.6 and 85 ± 60.1 versus 37 ± 17.2l, P < 0.002; motility: 63 ± 10.3 versus 55 ± 14.5 and 52 ± 19.6 versus 41 ± 13.7, P < 0.001, respectively). Similar associations were observed in oligozoospermic men (concentration: 10 ± 4.2 versus 9 ± 5.9 and 10 ± 6.3 versus 6 ± 3.1, P < 0.03; motility: 47 ± 17.1 versus 39 ± 6.2 and 39 ± 22 versus 27 ± 18.3, P < 0.003, respectively). The above associations of the combined genotypes with sperm concentration and motility were confirmed in the total study population (P < 0.006 and P < 0.001, respectively). LIMITATIONS, REASONS FOR CAUTION Our study population was limited to Greek Caucasian adult males, residents of Northwest Greece. WIDER IMPLICATIONS OF THE FINDINGS The confirmation of our findings in other populations would verify the significance of AR and CYP19 genes for spermatogenesis. STUDY FUNDING/COMPETING INTERESTS This study did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector. The authors declare no conflicts of interest.

Association of serum and follicular fluid SHBG levels and SHBG (TAAAA)n polymorphism with follicle size in women undergoing ovarian stimulation

Objective. Sex hormone-binding globulin (SHBG) is the main transport protein of sex steroids. Recently, it has been found to be produced by granulosa lutein cells, suggesting a local role of SHBG in the ovary. The aim of this study was to investigate whether serum and follicular fluid SHBG levels and SHBG (TAAAA)n polymorphism are related to follicle size and pregnancy rate in women undergoing in vitro fertilisation. Methods. The study population consisted of 154 women with tubal and/or male-factor infertility undergoing IVF/ICSI and follicular fluid with oocytes from small (diameter ≤12 mm) and large (diameter ≥18 mm) follicles were studied. Genotyping of SHBG (TAAAA)n polymorphism was performed in peripheral blood samples. Serum and follicular fluids were used for hormones determination. Results. Women with short allele genotypes (with less than 8 TAAAA repeats) had higher number of small follicles compared to women with long allele genotypes (5.6 ± 3.9 vs. 3.5 ± 3.2 small follicles, p < 0.003). Follicular fluid SHBG levels correlated positively with serum SHBG levels (p < 0.001) and with the total number of follicles (p < 0.02). Furthermore, small follicles had higher follicular fluid SHBG concentration compared to large follicles (102.9 ± 35.0 nmol/l vs. 85.85 ± 34.88 nmol/l, p < 0.028). Conclusion. SHBG levels and the SHBG (TAAAA)n polymorphism are associated with follicle size.