Vascular endothelial growth factor, nitric oxide, and leptin follicular fluid levels correlate negatively with embryo quality in IVF patients

OBJECTIVE(S)

To measure vascular endothelial growth factor (VEGF), nitric oxide (NO) and leptin levels in individual ovarian follicles and to examine their relationships with perifollicular blood flow, follicular metabolic indices, and the developmental potential of the corresponding oocyte and embryo.

DESIGN

Prospective study.

SETTING

Academic, tertiary care institution.

PATIENT(S)

Unselected IVF patients.

INTERVENTION(S)

Color-pulsed Doppler analysis of perifollicular blood flow; determination of partial pressure of oxygen (pO2), partial pressure of carbon dioxide (pCO2), and pH and VEGF, leptin and NO levels in follicular fluid.

MAIN OUTCOME MEASURE(S)

Fertilization and day 3 embryo morphology and cleavage.

RESULT(S)

Fifty-five follicular fluid samples from 16 patients were studied. Mean follicular fluid levels were as follows: VEGF, 1,046+/-863.7 pg/mL (range, <63-3,332.7 pg/mL); NO3/NO2, 34.2+/-12 microM (range, 16.4-76.1 microM); and leptin, 20.1+/-12.1 ng/mL (range, 3.3-52.2 ng/mL). Vascular endothelial growth factor had a negative correlation with embryo morphology (r = -0.28, P = .01). Leptin demonstrated a negative correlation with follicular pO2 (r = -0.42, P = .005) and a positive correlation with follicular pCO2 (r = 0.36, P = .02). Follicular leptin levels correlated positively with VEGF levels (r = 0.46, P = .008) and with NO3/NO2 levels (r = 0.39, P =.006).

CONCLUSION(S)

Vascular endothelial growth factor, NO and leptin appear to be markers of follicular hypoxia and suboptimal embryo development. Whether fluctuations of these regulatory factors determine or reflect changes in the follicular microenvironment affecting oocyte developmental potential remains to be elucidated.

Perifollicular blood flow Doppler indices, but not follicular pO2, pCO2, or pH, predict oocyte developmental competence in in vitro fertilization

OBJECTIVE

To assess the relationships among perifollicular blood flow; follicular fluid pO2, pCO2, and pH; oocyte developmental capacity; preimplantation embryo quality.

DESIGN

Prospective study.

SETTING

Academic, tertiary care institution.

PATIENT(S)

Unselected, gonadotropin-stimulated IVF cycles.

INTERVENTION(S)

Color, pulsed Doppler analysis of perifollicular blood flow, and follicular pO2, pCO2, and pH determinations of randomly designated, mapped ovarian follicles.

MAIN OUTCOME MEASURE(S)

Fertilization and day 3 embryo cleavage and morphology.

RESULT(S)

Perifollicular vascularity indices were significantly and negatively correlated with day 3 embryo cleavage. Pulsatility index and S-D ratio also were significantly and negatively correlated with follicular pO2. The same correlation was found between resistance index and the fertilization rate of preovulatory oocytes. No relationship existed between follicular metabolic analysis and fertilization or embryo quality. The resistance index had a sensitivity of 0.57 and a specificity of 0.71 for the prediction of advanced embryo cleavage status.

CONCLUSION(S)

Results confirm and extend previous reports demonstrating that color, pulsed Doppler ultrasound analysis of individual preovulatory follicles during IVF therapy may provide an indirect index of the developmental competence of the corresponding oocyte. Although these methods may provide means to select embryos for transfer with the highest implantation potential, the moderate predictive power showed so far may limit their clinical applicability.

Embryo implantation in in vitro fertilization and intracytoplasmic sperm injection: impact of cleavage status, morphology grade, and number of embryos transferred

OBJECTIVE

The aims of this study were to compare preimplantation embryo quality in intracytoplasmic sperm injection (ICSI) with standard IVF and to examine the impact of age and number and quality of embryos transferred on implantation and pregnancy.

DESIGN

Retrospective, controlled clinical study.

SETTING

Academic tertiary center.

PATIENT(S)

We examined 211 consecutive couples undergoing ICSI who were matched with 211 couples undergoing IVF therapy during the same time frame.

INTERVENTION(S)

In vitro embryo culture.

MAIN OUTCOME MEASURE(S)

Day 3 embryo quality as judged by the number of blastomeres and morphology scoring.

RESULT(S)

Patients undergoing ICSI had a significantly reduced number of embryos with good morphology and cleavage compared with IVF cases. Nevertheless, pregnancy and abortion rates were similar when adjusted by age and number of embryos transferred. Average cleavage status and age were significant predictors of implantation. Women of advanced age had significantly lower embryo cleavage and implantation rates.

CONCLUSION(S)

[1] The cleaving status of day 3 embryos is a valuable, although limited, indicator of implantation outcome. [2] In vitro fertilization-derived embryos had better cleavage rates and morphology scores than ICSI-derived embryos; however, the implantation potential was similar for both groups. [3] The age-related decline in implantation rate was associated with impaired embryo growth rates.

Aneuploidy frequencies in semen fractions from ten oligoasthenoteratozoospermic patients donating sperm for intracytoplasmic sperm injection

OBJECTIVE

To determine aneuploidy frequencies in pellet and swim-up semen fractions from 10 infertile men with severe oligoasthenoteratozoospermia (OAT) who were donating sperm for intracytoplasmic sperm injection and to determine whether the swim-up isolation method would successfully separate aneuploid from haploid sperm.

DESIGN

Prospective study.

SETTING

Infertility clinic and molecular genetics laboratory.

PATIENT(S)

Ten patients with severe OAT.

INTERVENTION(S)

Cytogenetic analyses by fluorescence in situ hybridization to determine aneuploidy frequencies for chromosomes 1, 13, 18, 21, X, and Y in sperm from swim-up and pellet fractions.

MAIN OUTCOME MEASURE(S)

Gametic aneuploidy was scored in sperm fractions separated by the swim-up technique and clinical results after intracytoplasmic sperm injection were tabulated.

RESULT(S)

In all cases, chromosome aneuploidy levels in patients were significantly greater than in controls. The type and percentage of aneuploid sperm for all patients with OAT found in both swim-up and pellet fractions were not different, with the exception of diploid sperm, which remained in the pellet fraction. After ET, 2 (20%) of 10 couples achieved successful pregnancies.

CONCLUSION(S)

The data show significantly higher rates of diploidy, autosomal disomy and nullisomy, sex chromosome disomy and nullisomy, and total aneuploidy in sperm from all separated fractions obtained from all patients with OAT versus controls. This patient population with OAT may be at increased risk of producing aneuploid offspring.

Intra- and inter-laboratory variability in the assessment of sperm morphology by strict criteria: impact of semen preparation, staining techniques and manual versus computerized analysis

We designed prospective studies to compare manual and computerized analysis of sperm morphology by strict criteria using different semen processing and staining techniques. A total of 54 semen samples were studied; slides were prepared from each subject from liquefied semen and after washing, and stained with Diff-Quik or Papanicolaou. An intra-laboratory, blind assessment was performed manually (two observers) and using a computerized analyser (two readings). This demonstrated a very good correlation between manual analysis of liquefied and washed samples with both staining techniques [intraclass coefficient (ICC) = 0.93 and 0.83]. Greater agreement was observed between computerized readings (washed samples) of Diff-Quik (ICC = 0.93) than of Papanicolaou-stained slides (ICC = 0.66). An excellent intra-laboratory correlation was observed for within-computer readings (ICC = 0.93). There was moderate agreement between inter-laboratory computer readings (two centres, ICC = 0.72). Although there was lower inter-laboratory agreement for manual and manual versus computer readings, overall results of all manual and computer analyses showed good agreement (ICC = 0.73). Diff-Quik staining is reliable for both manual (liquefied) and computer (washed) analysis of strict sperm morphology. Intra- and inter-computer analyses using this method reached satisfactory levels of agreement. There is still high inter-laboratory variability for the manual method.

Endometrial estrogen and progesterone receptor and pinopode expression in stimulated cycles of oocyte donors

OBJECTIVE

To study the effect of controlled ovarian hyperstimulation and the ovarian response on several features of endometrial morphology simultaneously.

DESIGN

Prospective controlled study.

SETTING

Academic infertility center.

PATIENT(S)

Twenty-five oocyte donors undergoing COH and 10 ovulatory controls.

INTERVENTION(S)

Endometrial biopsies during the luteal phase and measurement of serum E2 and progesterone levels on days 12, 13, and 18-20.

MAIN OUTCOME MEASURE(S)

Endometrial morphology as judged by histologic dating, pinopode expression, and estrogen and progesterone receptor content.

RESULT(S)

Controlled ovarian hyperstimulation caused the early expression of endometrial features as judged by histologic dating criteria, estrogen and progesterone receptor expression, and the timing of pinopode expression in many of the subjects. A significant correlation within subjects with regard to their particular result on any one measure (e.g., histologic examination) and the others (e.g., estrogen and progesterone receptors, pinopodes) was observed. Those with higher levels of progesterone the day after hCG administration exhibited the most prematurity of morphologic features.

CONCLUSION(S)

Many controlled ovarian hyperstimulation cycles are associated with synchronous early expression of the expected pattern of histologic features, estrogen and progesterone receptors, and pinopodes. The most predictive feature of this premature expression was the level of progesterone the day after hCG administration.

The value of basal serum follicle stimulating hormone, luteinizing hormone and oestradiol concentrations following pituitary down-regulation in predicting ovarian response to stimulation with highly purified follicle stimulating hormone

The value of gonadotrophin and oestradiol concentrations following pituitary down-regulation with leuprolide acetate in predicting ovarian response to stimulation was evaluated in three groups of women undergoing ovarian stimulation for in-vitro fertilization with highly purified follicle stimulating hormone (FSH). Leuprolide acetate was started in the midluteal phase, and either stopped at menses (IVF-SL group, n = 3), or continued throughout stimulation (IVF-LL group, n = 38; oocyte donors, n = 58). Ovarian stimulation was started on cycle day 3, after blood was drawn for down-regulated FSH, luteinizing hormone (LH) and oestradiol. Higher down-regulated LH was predictive of higher oestradiol on day 5 of stimulation in both IVF groups, and of need for fewer ampoules in the IVF-LL group, but not of oestradiol on day of human chorionic gonadotrophin (HCG) administration or number of oocytes retrieved. Higher FSH after down-regulation predicted yield of fewer oocytes in the donor and IVF-LL groups, and higher oestradiol on day 5 of stimulation, need for fewer ampoules and a shorter duration of therapy in both IVF groups. Higher oestradiol after down-regulation was associated with higher oestradiol on day 5 of stimulation and on day of HCG administration, a shorter duration of therapy and need for fewer ampoules in all groups. Whereas these results do not ascribe any predictive significance to LH, they suggest that oestradiol and FSH concentrations after down-regulation are predictive of the pattern of ovarian response to stimulation and of oocyte yield.

Modulation of sperm tail protein tyrosine phosphorylation by pentoxifylline and its correlation with hyperactivated motility

OBJECTIVE

To assess the effect of pentoxifylline on human sperm functions that are crucial to fertilization.

DESIGN

Prospective, controlled study.

SETTING

Academic tertiary care institute.

PATIENT(S)

Healthy male sperm donors.

INTERVENTION(S)

The effects of pentoxifylline (3.6 mM) on hyperactivated motility, sperm binding to the zona pellucida, and sperm protein tyrosine phosphorylation were evaluated.

MAIN OUTCOME MEASURE(S)

Hyperactivated motility was assessed by computer-assisted motion analysis, and tight binding of sperm to homologous zonae pellucidae was examined using the hemizona assay. Sperm protein phosphorylation was evaluated using indirect immunofluorescence with an antibody to phosphotyrosine (PY20).

RESULT(S)

Pentoxifylline significantly stimulated hyperactivated motility at 1 hour and 4 hours; it also significantly increased sperm binding to the zona pellucida and enhanced sperm tail tyrosine phosphorylation at 4 hours under capacitating conditions. There was a statistically significant correlation between hyperactivated motility and sperm tail protein phosphorylation.

CONCLUSION(S)

Pentoxifylline stimulates sperm functions that are essential to achieving fertilization under in vitro conditions in sperm obtained from fertile men. The enhancement of hyperactivated motility is associated with the stimulation of sperm tail tyrosine phosphorylation, suggesting a causal relation and the involvement of a modulatory effect after cyclic adenosine monophosphate-dependent phosphorylation of intermediate proteins.

Pregnancy following transfer of ooplasm from cryopreserved-thawed donor oocytes into recipient oocytes

OBJECTIVE

To determine if frozen-thawed donor oocytes could be used to provide cytoplasm for transfer into patients' oocytes to improve subsequent embryonic development.

DESIGN

Prospective evaluation of the procedure in consenting IVF patients.

SETTING

Assisted reproductive technology program.

PATIENT(S)

The study was open to consenting IVF patients (of any age) with a history of poor embryo quality or those couples in which the wife's age was > or = 40 years.

INTERVENTION(S)

Transfer of donor egg cytoplasm from frozen-thawed oocytes into the oocytes of infertile recipients.

MAIN OUTCOME MEASURE(S)

Donor oocyte survival following cryopreservation, fertilization following cytoplasmic transfer into recipient oocytes, embryo quality, and pregnancy outcome.

RESULT(S)

Oocytes collected from four donors were cryopreserved and 61% (28/46) survived the thaw procedure. Cytoplasmic transfer was performed on the eggs of four patients, with fertilization occurring in 70.3% (26/37). Twin pregnancy was established in one patient (35 years of age) with a history of poor embryo quality.

CONCLUSION(S)

Cryopreserved donor oocytes may provide a source of cytoplasm for transfer into recipient oocytes, eliminating the need for cycle synchronization between donor and infertile patient.

Species specificity of human and murine anti-ZP3 synthetic peptide antisera and use of the antibodies for localization and identification of ZP3 or ZPC domains of functional significance

The mammalian zona pellucida has an important function in the fertilization process. The zona pellucida protein 3 (ZP3 or ZPC) is the ligand for primary sperm binding and induces the acrosome reaction. In various species, ZP3 primary structures are highly conserved as revealed by cDNA cloning. The objective of these studies was to localize ZP3 protein using antisera generated against defined synthetic peptides that are specific for mouse or for human ZP3. Immunohistochemistry and transmission electron microscopy were applied to murine and human ovary sections. Immunochemical studies were performed in hemizonae pellucidae from microbisected human oocytes. Using the competitive hemizona assay and various anti-ZP3 antibodies, we further intended to identify human ZP3 epitopes of functional significance. Our results showed that antiserum AS ZP3-9 (mouse specific) detected mouse ZP3 protein in mouse oocytes and in immunoblots, whereas AS ZP3-14 (human specific) detected human ZP3 protein in human ovary sections, native hemizonae pellucidae and in immunoblots. ZP3 material was also detected in cumulus cells by immunohistochemistry. Ultrastructural studies showed an equal distribution of ZP3 throughout the zona pellucida. The human competitive hemizona assay revealed that none of the anti-ZP3 synthetic peptide antisera affected sperm binding suggesting that those epitopes are not involved in primary sperm binding. Anti-porcine ZP3 beta protein antibodies (polyclonal) blocked human sperm-zona pellucida binding. In summary, these anti-ZP3 synthetic peptide antibodies specifically reacted with intact ZP3 protein (murine and human) but did not inhibit human sperm-zona pellucida binding; anti-ZP3 antibodies can therefore be used as biomarkers for ZP3 localization and function.

Assessment of interlaboratory and intralaboratory sperm morphology readings with the use of a Hamilton Thorne Research integrated visual optical system semen analyzer

OBJECTIVE

To evaluate the level of variance produced in a multicenter study with the use of a computer-assisted sperm morphology analyzer.

DESIGN

A multicenter, prospective, blinded study.

SETTING

Assisted reproduction research laboratories.

PATIENT(S)

Semen samples produced for assisted reproductive procedures.

INTERVENTION(S)

Hamilton Thorne Research (Beverly, MA) integrated visual optical system semen analyzers were used at five different centers to evaluate the same set of 30 slides that were prepared and numerically coded at Tygerberg Hospital in Tygerberg, South Africa.

MAIN OUTCOME MEASURE(S)

The percentage of normal sperm.

RESULT(S)

Interlaboratory coefficients of variation (CVs) ranged between 16.31% and 23.09%. One of the participating laboratories produced an approximately 14% (-6.5-7.7) limits of agreement analysis, with a CV of 11.36%, for its duplicate readings. The use of a 10% normal sperm morphology cutoff point to determine discordance levels produced rates ranging between 10% and 23.3% for the interlaboratory and intralaboratory readings. This level of discordance equates with < or = 7 of the corresponding readings from two laboratories falling into a different normal sperm morphology group (< or = 10% or >10%).

CONCLUSION(S)

The magnitudes of variation produced by the readings performed in our study reached the same level as for the manual evaluation of sperm morphology. A < 10% CV can be obtained if the correct quality control measures are implemented.

Pentoxifylline stimulates various sperm motion parameters and cervical mucus penetrability in patients with asthenozoospermia

Pentoxifylline (PTX) was incubated in vitro with human spermatozoa to examine its effects on sperm motility characteristics and bovine cervical mucus penetrability (BCMP). Sperm motion parameters were assessed by computer-assisted motion analysis (CASA) using HTM-IVOS and BCMP was evaluated using the Penetrak kit. In vitro incubation with PTX (1 mg ml-1; 3.6 mM, 30 min) did not significantly change percentage motility, average path velocity (VAP), straight-line velocity (VSL) or beat cross frequency (BCF) of spermatozoa from normozoospermic or asthenozoospermic samples. However, it significantly increased curvilinear velocity (VCL), amplitude of lateral head displacement (ALH) and hyperactivated motility (HA), and significantly decreased linearity (LIN) of spermatozoa from both samples. Pentoxifylline was found to increase BCMP scores for spermatozoa from asthenozoospermic samples, but did not affect scores for spermatozoa from normozoospermic samples. Bovine cervical mucus penetrability (BCMP) was found to be positively and significantly correlated with the percentage motility of both non-PTX-treated and PTX-treated spermatozoa for asthenozoospermic samples. These results demonstrated that PTX enhanced several motion sperm parameters as well as BCMP in asthenozoospermic samples and suggest a potential use of the methylxanthine in infertile patients with motility defects undergoing artificial insemination.

Plasma membrane integrity of cryopreserved human sperm: an investigation of the results of the hypoosmotic swelling test, the water test, and eosin-Y staining

OBJECTIVE

[1] To examine the relationship between sperm membrane integrity and motion parameters before and after cryopreservation; [2] to determine the capacity of the membrane integrity tests to predict the outcome of cryopreservation in fertile and infertile men; and [3] to examine the degree of agreement between tail and head membrane integrity of testicular and ejaculated immotile sperm cryopreserved for intracytoplasmic sperm injection.

DESIGN

Prospective study.

SETTING

Academic tertiary care institution.

PATIENT(S)

Fertile donors and normozoospermic oligozoospermic, and asthenozoospermic subfertile men.

INTERVENTION(S)

Semen samples were cryopreserved and thawed for analysis.

MAIN OUTCOME MEASURE(S)

Sperm membrane integrity and computer-assisted motion parameters.

RESULT(S)

The hypoosmotic swelling test and water test had a significant and positive correlation in the fresh and cryopreserved ejaculates of all groups. The results of the hypoosmotic swelling test correlated positively with the percent motility in the fresh ejaculates of fertile and subfertile men. None of the membrane integrity tests correlated with the cryosurvival rate in any group. In the ejaculated and testicular samples with no postcryopreservation motility, the simultaneous assessment of hypoosmotic swelling test and eosin showed that of 33% sperm exhibiting coiling with the hypoosmotic swelling test, only 9% were eosin negative, whereas 24% were eosin positive.

CONCLUSION(S)

[1] The water test may be a simpler replacement for the hypoosmotic swelling test; [2] none of the membrane integrity tests predicted sperm motility after cryopreservation; and [3] there was a high degree of disagreement between the hypoosmotic swelling test and eosin in the samples with no postcryopreservation motility.

Hemochromatosis and male infertility

BACKGROUND

The clinical association of hemochromatosis and infertility is rare. Hemochromatosis may affect fertility through a variety of mechanisms.

CASE

A 44-year-old man and his 36-year-old wife presented with primary infertility of 7 years' duration. The husband was diagnosed as having idiopathic hemochromatosis, abnormal glucose tolerance, and hypogonadism accompanied by impotence, retrograde ejaculation, and azoospermia. Treatment consisted of phlebotomies followed by gonadotropins, which corrected retrograde ejaculation and improved semen characteristics. Concomitant pelvic factors in the woman were corrected endoscopically. After failure of pregnancy with ovulation stimulation and intrauterine inseminations, a singleton pregnancy was achieved by in vitro fertilization, augmented with intracytoplasmic sperm injection.

CONCLUSION

This case underscores the need to consider advanced reproductive technologies after the failure of specific, first-line therapeutic options in infertile couples.

Analysis of implantation in assisted reproduction through the use of serial human chorionic gonadotropin measurements

PURPOSE

Our purpose was to examine implantation of singleton pregnancies achieved following various assisted reproductive technologies (ARTs) through the appearance and rising titers of serum human chorionic gonadotropin (hCG) levels.

METHODS

A total of 114 singleton pregnancies resulting from in vitro fertilization and intrauterine insemination was analyzed. Patients were divided into five groups according to the type of ovarian stimulation protocol [gonadotropin stimulation with/without the use of gonadotropin-releasing hormone agonist (GnRHa), long protocol, or flare-up technique] and to the day of embryo transfer (day 2 or day 3 after oocyte retrieval). Serial serum hCG levels were measured between 10 and 25 days after fertilization and log-transformed. Linear regression analyses were performed and extrapolated to hCG = 10 mIU/ml (hCG10), which was used as an estimate of detectable implantation. The slopes of the regression lines were used to estimate the rising speed of hCG.

RESULTS

There were no significant differences in the days of hCG in maternal serum to reach 10 mIU/ml (implantation) or in the slopes of the regression lines for all five studied groups.

CONCLUSIONS

The appearance of hCG in maternal serum was used to assess the time of clinically detectable implantation. Furthermore, because hCG production is a marker of trophoblastic activity, its serum doubling time was used as an indicator of embryo quality. Results showed that in various ART protocols with and without GnRHa, there were no significant differences in implantation time or embryo quality. Embryo development in early pregnancy follows a preprogrammed-timing schedule and depends mainly on the embryonic age of the healthy, successfully implanted conceptus.

Involvement of selectin-like carbohydrate binding specificity in human gamete interaction

The recognition of carbohydrate epitopes by complimentary protein receptors has been shown to be a critical factor in gamete interaction in many different animal species. In this study it was hypothesized that, in the human, gamete binding requires an interaction between selectin ligands on the zona pellucida and putative egg binding proteins on the sperm surface. The hemizona assay (a unique internally controlled bioassay that evaluates tight binding of sperm to the zona) and advanced methods of carbohydrate analysis were used to test this hypothesis. From these tests it was shown that oligosaccharide recognition is also required for initial human gamete binding. This study suggests the existence of distinct egg binding proteins on human sperm that can bind to selectin ligands. Additionally, the results suggest a possible convergence in the types of carbohydrate sequences recognized during initial human gamete binding and immune/inflammatory cell interactions. Glycoconjugates that manifest selectin-ligand activity and that express specific carbohydrate epitopes have potent contraceptive and immunosuppressive effects. Such specific oligosaccharide sequences may provide an appropriate recognition signal for embryo development and protection.

Semen quality: is there a paternal effect on pregnancy outcome in in-vitro fertilization/intracytoplasmic sperm injection?

The objective of this study was to investigate the role of the spermatozoon (paternal effects) on implantation and pregnancy outcome in in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). Male individuals of three types were analysed: infertile men with oligoasthenoteratozoospermia (OAT), infertile men with normozoospermia and fertile men (donors). Female counterparts were judged to have comparable egg quality within two groups studied, i.e. infertile women with pure mechanical (tubal) infertility and recipients of donor eggs. There were significantly higher differences in implantation and pregnancy rates in groups using donor spermatozoa and donor egg recipients. Analyses of key set groups revealed a trend toward a poorer implantation and pregnancy outcome when comparing OAT versus normozoospermic patients within IVF, but not within ICSI treatments, in couples with tubal infertility. In couples who were recipients of donor eggs, no differences were observed between OAT patients treated by ICSI and normozoospermic patients treated with IVF. No significant differences were observed in miscarriage rates within any groups studied. In conclusion, the poorer results observed in OAT patients undergoing IVF may be secondary to spermatozoal effects due to a high insemination concentration. Overall, there does not seem to be a significant effect of severe male infertility (OAT) on implantation and pregnancy outcome. However, this does not preclude that specific sperm aberrations may exert a negative effect on embryogenesis and therefore on implantation potential following assisted or in-vivo reproduction.

Immunological identification of zona pellucida 2 (ZP2) protein in human oocytes

The ZP2 protein is a zona pellucida glycoprotein that plays a major role in fertilization. It mediates secondary binding of spermatozoa and is one of the proteins that are involved in zona 'hardening'. ZP2 proteins were identified in various mammalian zonae pellucidae. Their primary structures are highly conserved as revealed by cDNA cloning. Antisera were used against synthetic peptides generated either against a ZP2 amino acid that is homologous in human and mouse ZP2 amino acid sequences (AS ZP2-20) or antibodies against a synthetic human ZP2 peptide (AS ZP2-26). Immunoblots showed that antiserum AS ZP2-20 and AS ZP2-26 strongly recognized human ZP2 protein with an apparent molecular mass of about 72 kDa; both antisera reacted with a minor immunoreactive polypeptide at 96 kDa. In human ovary sections, both antisera revealed immunoreactivity to human zonae pellucidae. Immuno-electron microscopy demonstrated an equal distribution of ZP2 throughout the human zona pellucida. Considerable amounts of immunoreactive material were observed in the ooplasm; some ramification-like extensions of zona pellucida antigen were found close to cells surrounding the oocyte. Our results indicate that antisera against synthetic ZP2 peptides can be used as specific markers for the identification of ZP2 protein in human oocytes.

Comparison of various methods of processing human cryopreserved-thawed semen samples

We compared the efficacy of various methods of processing cryopreserved-thawed samples for the recovery of functionally adequate spermatozoa as assessed by the response to the sperm stress test (SST), an index of temperature activated sperm membrane lipid peroxidation, and immediate and delayed changes in sperm viability and motion parameters. Donor semen samples (n = 28) were cryopreserved-thawed and divided into six equal parts, one part was used as control and the remaining parts were used to compare five methods of sperm processing as follows: direct Percoll gradient processing, washing by one-step or stepwise addition of the washing medium followed by Percoll processing, and washing by one-step or stepwise addition of the washing medium. Additional samples (n = 10) were evaluated for the immediate and delayed (6 h at 37 degrees C) impact of one-step and stepwise washing (without Percoll separation). Compared with wash-only methods, samples processed using Percoll had a significantly higher SST score (P = 0.001), motility, rapid spermatozoa (>50 microm/s), curvilinear velocity and motility index (P < 0.001). Comparing various Percoll methods, direct Percoll processing resulted in the highest number of motile spermatozoa recovered (P < 0.00001) and a higher SST score based on curvilinear velocity (P = 0.001). Stepwise washing gave a significantly higher number of motile spermatozoa (P < 0.001) but with a significantly lower SST score based on the concentration of motile spermatozoa (P = 0.001), motility (P = 0.001) and motility index (P = 0.01). Sperm viability and motion parameters after 6 h of incubation showed no difference between one-step and stepwise washing. In conclusion, compared with wash-only methods, Percoll processed samples resulted in the recovery of spermatozoa with superior quality as assessed by SST and motion analysis. One-step washing of the samples gave an overall comparable recovery compared to the samples prepared stepwise. Having significantly higher SST scores, similar viability and the maintenance of motility, one-step washing may be a better method of processing thawed samples than the stepwise washing.

Glycodelins: role in regulation of reproduction, potential for contraceptive development and diagnosis of male infertility

Glycodelins are glycoproteins synthesized in various glands, with sequence homology to beta-lactoglobulins, and named according to their unique oligosaccharide structures. We purified, cloned and sequenced endometrium- and seminal plasma-derived glycodelins (GdA and GdS respectively) and found that they are involved in various types of cell-cell communications. These include interactions between the spermatozoon and the egg, and between immune cells and their targets. Endometrial GdA inhibits sperm-egg binding, whereas the differently glycosylated GdS in seminal plasma does not. These observation are of interest for reproductive physiology, detection of causes of infertility, and they also may have potential for contraceptive development.

Cessation of gonadotropin-releasing hormone agonist therapy combined with high-dose gonadotropin stimulation yields favorable pregnancy results in low responders

OBJECTIVE

To evaluate the pregnancy results of an ovarian hyperstimulation protocol for IVF-ET that combines GnRH agonist down-regulation, cessation of GnRH agonist therapy with the onset of menstruation, and high-dose gonadotropin administration in low responders.

DESIGN

Prospective analysis.

SETTING

Academic IVF program.

PATIENT(S)

One hundred eighty-two low responders undergoing 224 IVF-ET cycles.

INTERVENTION(S)

Down-regulation was obtained with the administration of leuprolide acetate beginning in the midluteal phase and ending with the onset of menses. Daily administration of 6 ampules of FSH alone or in combination with hMG was initiated on cycle day 3.

MAIN OUTCOME MEASURE(S)

Stimulation characteristics and pregnancy rates (PRs) were compared between fresh cycles in which pure FSH alone was used and 35 cycles in which a combination of FSH and hMG was administered.

RESULT(S)

The clinical PR per transfer, the ongoing PR per transfer, and the implantation rate were 32%, 24%, and 9%, respectively. No differences were noted between cycles in which pure FSH alone was used in comparison with cycles in which a combination of FSH and hMG was administered.

CONCLUSION(S)

Short-term ovarian suppression begun in the luteal phase and discontinued with the onset of menses followed by high-dose stimulation with gonadotropins yields favorable pregnancy results in low responders.