Category Archives: Human Reproduction

BACKGROUND

Glycodelin-A interacts with spermatozoa before fertilization, but its role in modulating sperm functions is not known. Zona pellucida-induced acrosome reaction is crucial to fertilization and its dysfunction is a cause of male infertility. We hypothesized that glycodelin-A, a glycoprotein found in the female reproductive tract, potentiates human spermatozoa for zona pellucida-induced acrosome reaction.

METHODS

Glycodelin isoforms were immunoaffinity purified. The sperm intracellular cAMP concentration, protein kinase-A (PKA) and extracellular signal-regulated kinase (ERK) activities, and intracellular calcium were measured by ELISA, kinase activity assay kits and Fluo-4AM technique, respectively. The phosphorylation of inositol 1,4,5-trisphosphate type-1 receptor (IP3R1) mediated by ERK was determined by western blotting. Zona pellucida-induced acrosome reaction was detected by Pisum sativum staining.

RESULTS

Pretreatment of spermatozoa with glycodelin-A significantly up-regulated adenylyl cyclase/PKA activity and down-regulated the activity of ERK and its phosphorylation of IP3R1, thereby enhancing zona pellucida-induced calcium influx and zona pellucida-induced acrosome reaction. Glycodelin-F or deglycosylated glycodelin-A did not have these actions. Treatment of spermatozoa with a protein kinase inhibitor abolished the priming activity of glycodelin-A, whilst ERK pathway inhibitors mimic the stimulatory effect of glycodelin-A on zona pellucida-induced acrosome reaction.

CONCLUSIONS

Glycodelin-A in the female reproductive tract sensitizes spermatozoa for zona pellucida-induced acrosome reaction in a glycosylation-specific manner through activation of the adenylyl cyclase/PKA pathway, suppression of extracellular signal-regulated kinase activation and up-regulation of zona pellucida-induced calcium influx. The action of glycodelin-A may be important in vivo to ensure full responsiveness of human spermatozoa to the zona pellucida.

BACKGROUND

Protamine content is necessary for proper sperm chromatin condensation and subsequent male fertility. The exact effect of smoking on male fertility remains controversial. The objective of this study was to evaluate the effect of smoking on protamine content of sperm in smoker and non-smoker patients.

METHODS

Protamines 1 (P1) and 2 (P2) were quantified by gel electrophoresis in the sperm of 53 smokers and 63 non-smokers. Sperm DNA fragmentation was analyzed employing the terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling (TUNEL) assay and non-condensed chromatin was evaluated using chromomycin A₃ (CMA₃). Levels of smoking and oxidative stress markers were determined in seminal plasma using an enzyme linked immunosorbant assay (ELISA) and chemical reactions.

RESULTS

Protamine 2 concentrations were significantly lower (P < 0.050) in smokers than in non-smokers. In contrast P1/P2 ratios were significantly higher (P < 0.010) in smokers (1.34 ± 0.46 ng/10⁶ sperm) than in non-smokers (1.11 ± 0.20 ng/10⁶ sperm). The oxidative stress and smoking markers, reactive oxygen species (ROS), malondialdehyde, 8-Hydroxyguanosine (8-OHdG) and cotinine were significantly higher (P < 0.010) in smokers than in non-smokers, and correlated significantly (P < 0.050) with P1/P2 ratios. P2 showed significant negative (P < 0.050) correlations with ROS, 8-OHdG and cotinine. CMA₃ and TUNEL were also significantly higher (P < 0.010) in smokers (36.4 ± 8.1 and 17.4 ± 5.3%) than in non-smokers (29.8 ± 7.1 and 11.3 ± 4.2%).

CONCLUSIONS

This is the first study to evaluate the effect of smoking on protamines. Abnormal elevation of the P1/P2 ratio appears to be associated with aberrant P2 expression in smokers. These results suggest that induced oxidative stress by cigarette smoking may have significant inverse effect on the protamination process by disrupting P2.

BACKGROUND

We have recently shown that women with endometriosis express an increased amount of telomerase and nucleolin, with concomitant loss of -H2AX in eutopic endometrium. To further examine these selected factors that regulate cell fate, in the pathogenesis of endometriosis, we studied the expression of telomerase, nucleolin, proliferating cell nuclear antigen and -H2AX in ectopic endometriotic deposits from women, and in matched eutopic and ectopic endometrial tissue from a baboon model of endometriosis.

METHODS

Ectopic active peritoneal endometriotic lesions were collected from seven symptomatic women. Endometriosis was induced in six baboons by intra-peritoneal autologous inoculation of menstrual endometrium. Eutopic and matched ectopic endometrial tissues were collected prior to and 6, 12 and 15 months after the induction of endometriosis as previously described. Eutopic endometrium was also obtained from eight healthy fertile control baboons. Immunohistochemistry was performed as previously described, and telomerase activity was confirmed using the telomeric repeat amplification protocol assay.

RESULTS

All active human endometriotic lesions expressed the proliferative markers but showed weak or absent staining for -H2AX. A similar expression pattern of these markers was seen in the ectopic lesions of the baboons with induced disease. In these baboons, the eutopic endometrium also showed intense immunoreactivity for all proliferative markers 6–12 months after induction with a parallel loss of -H2AX. The opposite staining pattern was seen in eutopic endometrium of healthy animals and in pre-induction endometrium of animals with induced disease.

CONCLUSIONS

Endometriotic lesions have excess proliferative potential; in baboons, these were present within 12 months of the initiation of the disease. In eutopic tissue, these changes appear to be induced by the development of endometriosis.

BACKGROUND

Pre-eclampsia, a syndrome usually accompanied by incomplete spiral arterial modification, occurs at an increased frequency in diabetic women. Hyperglycemia in non-obese type 1 diabetic (NOD) mice impairs gestational spiral arterial remodeling despite high local levels of interferon gamma (Ifng), the triggering cytokine in mice. Pregnancies in NOD.Ifng^–/– mice were assessed to investigate this issue.

METHODS

Fecundity was assessed using the breeding history, flushing of preimplantation embryos and histological and morphometric studies of implantation sites in normoglycemic (n-) and hyperglycemic (d-) females of NOD.Ifng^–/– and NOD genotypes.

RESULTS

NOD.Ifng^–/– but not NOD mice are mostly infertile. In NOD.Ifng^–/–, copulation often does not result in a post-implantation pregnancy. Defective fertilization and delayed preimplantation development limit n-NOD.Ifng^–/– fertility, and both mechanisms are exacerbated by hyperglycemia. At mid-gestation, implantation sites in n-NOD.Ifng^–/– and n-NOD mice are histologically similar. However, in d-NOD.Ifng^–/–, there is minimal development of spiral arteries, hypertrophy of the myometrial region containing uterine Natural Killer (uNK) cells and a deficit in cytoplasmic granule formation in the uNK cells.

CONCLUSIONS

Ifng contributes to the success of fertilization and to the rate of preimplantation mouse embryo development in normogylcemic and hyperglycemic pregnancies. A physiological role for this cytokine in human preimplantation development merits investigation.

BACKGROUND

The aim of this study was to describe the perceptions of infertile men regarding the impact of infertility on their intimate relationships, their experience of treatment and their sources of information and support.

METHODS

A cross-sectional survey of a consecutive cohort of men diagnosed 5 years earlier as infertile at Melbourne IVF and the Royal Women's Hospital Reproductive Services, Melbourne was conducted. Study-specific questions assessed the impact of male factor infertility on the intimate relationships, their perceived quality of infertility-related health care and their preferred sources of infertility-related information and personal support and the effectiveness of these.

RESULTS

The response rate was 41% (112/276). Male factor infertility was reported to have had a negative impact on the intimate partner relationship by 25% of men, and 32% reported a negative effect on their sexual satisfaction. Satisfaction with medical care and clinic information was high and not influenced by the outcome of the treatment. Clinic-provided information and discussion with clinic staff were the most strongly preferred sources of information, and the partner and clinic staff were the most valued sources of personal support. Very few men found support groups useful and less than half confided in friends.

CONCLUSIONS

The findings suggest that for a significant subgroup of men, male factor infertility affects their intimate relationship negatively. Wider sources of social support are not used by infertile men as they rely predominantly on clinic-provided information and support. This indicates that psychologically informed supportive clinical care is particularly important for men diagnosed as infertile.

BACKGROUND

Currently, no published data exist about the gonadal function of children born after ICSI. To evaluate potential risk of testicular seminal dysfunction in boys born to fathers with compromised spermatogenesis, serum inhibin B (as a marker for spermatogenesis) was assessed.

METHODS

We recruited 50 pubertal adolescents from the oldest cohort of infants born following ICSI. Cross-sectional serum inhibin B levels of all 50 ICSI adolescents, and longitudinal serum inhibin B (assessed at 8 and 14 years) in 25 boys, are reported.

RESULTS

A statistically significant increase in inhibin B levels was observed between 8 (mean 69 ng/l, SD ± 35) and 14 years (mean 145 ng/l, SD ± 41; P < 0.001). In three quarters of the ICSI boys an increase in serum inhibin B levels of at least 30% between 8 and 14 years was observed. In all but 4 of the 14-year-old ICSI boys serum inhibin B was normal. Serum inhibin B levels in boys from fathers with severe oligozoospermia did not differ from concentrations in boys from fathers without severe oligozoospermia (154 ± 51 and 142 ± 47 ng/l, respectively; P = 0.4).

CONCLUSIONS

The majority of ICSI boys have a significant increase in serum inhibin B, attaining normal values for pubertal status at the age of 14 years. ICSI adolescents from fathers with severely compromised spermatogenesis do not have lower inhibin B levels than those with fathers with normal spermatograms. Further follow-up of the spermatogenic potential of ICSI teenagers up to young adulthood is mandatory to confirm a normal reproductive capacity.