Aromatase (CYP19) gene variants influence ovarian response to standard gonadotrophin stimulation.

PURPOSE: The association of cytochrome P450 aromatase gene CYP19(TTTA) ( n ) polymorphism with ovarian response to FSH stimulation was explored. METHODS: Three hundred women undergoing medically assisted reproduction and 300 women with at least one spontaneous pregnancy participated in the study. CYP19(TTTA) ( n ) polymorphism was genotyped, while serum hormones were determined. During oocyte retrieval, the follicular size, the follicle and oocyte numbers were recorded. RESULTS: Six CYP19(TTTA) ( n ) alleles with 7 to 12 repeats were revealed. Women homozygous for long CYP19(TTTA) ( n ) alleles presented with lower serum FSH levels at the third day of the menstrual cycle (p < 0.001) and higher large follicle numbers (p < 0.01), compared to women homozygous for short CYP19(TTTA) ( n ) alleles. The CYP19(TTTA) ( 7 ) allele was associated with higher serum FSH levels (p < 0.003), with lower total follicle (p < 0.02) and large follicle numbers (p < 0.03), while CYP19(TTTA) ( 7 ) allele-carriers presented more frequently with small follicles than CYP19(TTTA) ( 7 ) allele-non carriers (p < 0.01). CONCLUSIONS: CYP19 genetic variants were associated with ovarian reserve and response to standard gonadotrophin stimulation of women undergoing in vitro fertilization.

The ovarian response to standard gonadotrophin stimulation depends on FSHR, SHBG and CYP19 gene synergism.

PURPOSE: Follicle stimulating hormone, sex hormone-binding globulin and cytochrome P450 aromatase play crucial roles in the regulation of mammalian reproduction. The synergistic effect of FSHR 307(T/A)/FSHR 680(N/S), SHBG(TAAAA) ( n ) and CYP19(TTTA) ( n ) genotypes on ovarian response to standard gonadotrophin stimulation of women undergoing medically assisted reproduction (IVF/ICSI) was explored. METHODS: The study population consisted of 300 women under IVF/ICSI treatment and 300 women with at least with at least one successful child birth as controls. The polymorphisms were genotyped while the follicular size, the follicle and oocyte numbers were recorded during oocyte retrieval. RESULTS: The genotype analysis, excluding heterozygotes for each particular polymorphism, revealed eight combined homozygotic FSHR/SHBG/CYP19 genotypes. A gradual reduction in the number of follicles and oocytes from FSHR 307Thr/680Asn allele/long SHBG allele/long CYP19 allele homozygotes to FSHR 307Ala/680Ser allele/short SHBG allele/short CYP19 allele homozygotes was observed (20.36 ± 6.74 vs. 8.05 ± 2.47, p < 0.008 and 13 ± 4.63 vs. 6.1 ± 2.32, p < 0.02, respectively). CONCLUSIONS: FSHR/SHBG/CYP19 combined genotypes are associated with ovarian response to standard gonadotrophin stimulation of women undergoing medically assisted reproduction.

Assessment of sperm chromatin condensation and ploidy status using flow cytometry correlates to fertilization, embryo quality and pregnancy following in vitro fertilization.

PURPOSE: Sperm flow cytometry (SFC) was used to evaluate the association of sperm chromatin condensation and ploidy with fertilization, embryo development, pregnancy and abortion rates following IVF. METHODS: Conventional semen analysis was performed in one hundred fifty men, as well as SFC analysis, after acridine orange and propidium iodide staining, for the evaluation of sperm maturity and ploidy respectively. Conventional IVF was performed in all couples. RESULTS: Couples with low percentages of mature spermatozoa presented with lower fertilization rates (p < 0.005), lower rates of grade A embryos (p < 0.003) and lower pregnancy rates (p < 0.006), compared to couples with high percentages of mature spermatozoa. Couples with low total aneuploidy rates presented with higher fertilization rates (p < 0.007), higher rates of grade A embryos (p < 0.004) and higher pregnancy rates (p < 0.003), compared to couples with high total aneuploidy rates. CONCLUSIONS: Sperm chromatin condensation and ploidy constitute critical parameters for the evaluation of semen samples before IVF and for the identification of cases in need of ICSI application.

Association of TNFα, TNFR1, and TNFR2 polymorphisms with sperm concentration and motility.

Tumor necrosis factor α (TNFα) is a multifunctional cytokine that regulates various cellular processes related to spermatogenesis. Two types of cell receptors, TNFR1 and TNFR2, mediate TNFα activity. In the present study, we sought to explore the association of TNFα -857C→T, TNFR1 36A→G, and TNFR2 676T→G polymorphisms with sperm concentration and motility. Two hundred ninety men were examined during infertility investigation; of those, 170 men were normozoospermic and 120 were oligospermic. Polymerase chain reaction analysis revealed significant differences in genotype distribution of the TNFR1 36A→G polymorphism between normozoospermic and oligospermic men. Men with oligozoospermia presented TNFR1 36A/A genotypes less frequently than normozoospermic men (P < .001). The presence of the TNFR1 36G allele was significantly increased in oligospermic men (P < .001). Furthermore, the presence of the TNFR1 36G allele was associated with lower sperm concentration in normozoospermic men (P < .03) and in the total study population (P < .001), and with lower sperm motility in normozoospermic men (P < .007) and in the total study population (P < .001). No significant associations were found between TNFα -857C→T and TNFR2 676T→G polymorphisms and semen quality. The TNFR1 36A allele is associated with increased sperm concentration and motility in our series, supporting the significance of TNFR1 gene in semen quality.

Association of paraoxonase gene polymorphisms with sperm parameters.

Paraoxonase (PON) is a high-density lipoprotein-associated enzyme that prevents low-density lipoprotein oxidation. PON proteins, localized in the seminiferous tubules and in spermatozoa, have been implicated in the pathogenesis of male infertility. In the present study, we sought to explore the contribution of the PON gene variants to sperm parameters. One hundred twenty oligospermic and 170 normozoospermic men were examined during infertility investigation. DNA was extracted from spermatozoa, and the PON1(L/M) 55, PON1(Q/R) 192, and PON2(S/C) 311 polymorphisms were genotyped by polymerase chain reaction and digestion with restriction enzymes. The analysis revealed that oligospermic men presented PON1 55L/L, PON1 192Q/Q, and PON2 311S/S genotypes less frequently than normozoospermic men (P < .01, P < .01, and P < .001, respectively), whereas the PON1 55M, PON1 192R, and PON2 311C alleles were significantly increased in oligospermic men (P < .004, P < .008, and P < .008, respectively). The presence of PON1 55L allele was associated with higher sperm motility in oligospermic men (P < .001), in normozoospermic men (P < .01), and in the total study population (P < .01), and the PON1 192Q allele was associated with higher sperm motility in oligospermic men (P < .01), in normozoospermic men (P < .04) and in the total study population (P < .03). On the other hand, the PON2 311S was associated with higher sperm concentration in oligospermic men (P < .03), in normozoospermic men (P < .008), and in the total study population (P < .001). In our series, the PON1 55M and PON1 192R alleles were associated with decreased sperm motility whereas the PON2 311C allele was associated with decreased concentration, supporting the significance of PON genes in semen quality.

Estrogen receptor alpha and beta 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.