Developmental potential of embryos produced by in-vitro fertilization from gonadotrophin-releasing hormone antagonist-treated macaques stimulated with recombinant human follicle stimulating hormone alone or in combination with luteinizing hormone

Effect of trigger day serum luteinising hormone levels on the in-vitro fertilization outcome: an observational study

OBJECTIVE

Controlled ovarian stimulation leads to profound changes in the endocrine characteristics of the ovarian cycle. Serum luteinising hormone (LH) levels on the day of trigger have been shown to correlate with oocyte quality and pregnancy rate in antagonist cycles.

METHODS

This is an observational study of 86 women undergoing an antagonist in-vitro fertilisation cycle. Oocyte maturation trigger used was either Inj. human chorionic gonadotropin or Inj. triptorelin 0.2 mg s/c or a combination of both. Women were categorised into four groups based on serum LH levels on the day of trigger i.e., LH ≤0.5 (n=8), LH=0.6- 1.0 international units (IU)/L (n=12), LH=1.0-1.5 IU/L (n=13), and LH >1.6 IU/L (n=53) and the subgroup analysis was done based on type of trigger used.

RESULTS

Mature oocyte (MII) retrieval rate did not show a significant relation with serum LH levels (87%, 89%, 77%, and 76% in groups with LH <0.5, 0.5-1.0, 1.0-1.5, and >1.5 IU/L respectively; P-value=0.243). There was no significant difference in the clinical pregnancy rate either when women were split according to the type of trigger given or according to trigger day LH levels. Women with low LH levels (<0.5 IU/L) required significantly more doses of gonadotropins compared to women with LH levels of 1.0-1.5 IU/L. (3,531+1,133 vs. 2,281+938; P-value=0.01).

CONCLUSION

Based on the observation from the current study, there was no significant association of serum LH levels with MII retrieval rate and clinical pregnancy rate. The group with low LH levels required slightly longer days of stimulation.

Potential of human twin embryos generated by embryo splitting in assisted reproduction and research

BACKGROUND

Embryo splitting or twinning has been widely used in veterinary medicine over 20 years to generate monozygotic twins with desirable genetic characteristics. The first human embryo splitting, reported in 1993, triggered fierce ethical debate on human embryo cloning. Since Dolly the sheep was born in 1997, the international community has acknowledged the complexity of the moral arguments related to this research and has expressed concerns about the potential for reproductive cloning in humans. A number of countries have formulated bans either through laws, decrees or official statements. However, in general, these laws specifically define cloning as an embryo that is generated via nuclear transfer (NT) and do not mention embryo splitting. Only the UK includes under cloning both embryo splitting and NT in the same legislation. On the contrary, the Ethics Committee of the American Society for Reproductive Medicine does not have a major ethical objection to transferring two or more artificially created embryos with the same genome with the aim of producing a single pregnancy, stating that 'since embryo splitting has the potential to improve the efficacy of IVF treatments for infertility, research to investigate the technique is ethically acceptable'.

OBJECTIVE AND RATIONALE

Embryo splitting has been introduced successfully to the veterinary medicine several decades ago and today is a part of standard practice. We present here an overview of embryo splitting experiments in humans and non-human primates and discuss the potential of this technology in assisted reproduction and research.

SEARCH METHODS

A comprehensive literature search was carried out using PUBMED and Google Scholar databases to identify studies on embryo splitting in humans and non-human primates. 'Embryo splitting' and 'embryo twinning' were used as the keywords, alone or in combination with other search phrases relevant to the topics of biology of preimplantation embryos.

OUTCOMES

A very limited number of studies have been conducted in humans and non-human primates. The published material, especially the studies with human embryos, is controversial. Some reports suggest that twinning technology will find clinical use in reproductive medicine in the future, whereas others conclude the opposite that human twin embryos created in vitro are unsuitable not only for clinical, but also for research, purposes.

WIDER IMPLICATIONS

The blastomere biopsy technique of embryo splitting seems to be unsuitable for either clinical or research purposes; however, embryo bisection, a preferable method of cloning in veterinary medicine, has not yet been tested on human embryos.

Exposure of female macaques to Western-style diet with or without chronic T in vivo alters secondary follicle function during encapsulated 3-dimensional culture

Increased adiposity and hyperandrogenemia alter reproductive parameters in both animal models and women, but their effects on preantral follicles in the ovary remain unknown. We recently reported that Western-style diet (WSD) consumption over 1 year, with or without chronic exposure to elevated circulating T, increased the body fat percentage, elicited insulin resistance, suppressed estradiol and progesterone production, as well as altered the numbers, size, and dynamics of antral follicles in the ovary during the menstrual cycle in female macaques. Therefore, experiments were designed to compare the WSD and WSD+T effects to age-matched controls on the survival, growth, and function of isolated secondary follicles during 5 weeks of encapsulated 3-dimensional culture. Follicle survival significantly declined in the WSD and WSD+T groups compared with the control (CTRL) group. Although media progesterone levels were comparable among groups, androstenedione and estradiol levels were markedly reduced in the WSD and WSD+T groups compared with the CTRL group at week 5. Anti-Müllerian hormone levels peaked at week 3 and were lower in the WSD+T group compared with the WSD or CTRL group. Vascular endothelial growth factor levels also decreased at week 5 in the WSD+T group compared with the WSD or CTRL group. After human chorionic gonadotropin exposure, only antral follicles developed from the CTRL group yielded metaphase II oocytes. Thus, WSD with or without T exposure affects the cohort of secondary follicles in vivo, suppressing their subsequent survival, production of steroid hormones and local factors, as well as oocyte maturation in vitro.

Direct actions of androgens on the survival, growth and secretion of steroids and anti-Müllerian hormone by individual macaque follicles during three-dimensional culture

STUDY QUESTION

What are the direct effects of androgens on primate follicular development and function at specific stages of folliculogenesis?

SUMMARY ANSWER

Androgen addition altered primate follicle survival, growth, steroid and anti-Müllerian hormone (AMH) production, and oocyte quality in vitro, in a dose- and stage-dependent manner.

WHAT IS KNOWN ALREADY

Androgens have local actions in the ovary, particularly in the developing follicles. It is hypothesized that androgen promotes early follicular growth, but becomes detrimental to the antral follicles in primates.

STUDY DESIGN, SIZE, DURATION

In vitro follicle maturation was performed using rhesus macaques. Secondary (125-225 µm) follicles were mechanically isolated from 14 pairs of ovaries, encapsulated into alginate (0.25% w/v), and cultured for 40 days.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Individual follicles were cultured in a 5% O2 environment, in alpha minimum essential medium supplemented with recombinant human FSH. Follicles were randomly assigned to experiments of steroid ablation by trilostane (TRL), testosterone (T) replacement and dihydrotestosterone (DHT) replacement. Follicle survival and growth were assessed. Follicles with diameters ≥500 μm at Week 5 were categorized as fast-grow follicles. Pregnenolone (P5), progesterone (P4), estradiol (E2) and AMH concentrations in media were measured. Meiotic maturation and fertilization of oocytes from recombinant human chorionic gonadotrophin-treated follicles were assessed at the end of culture.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared with controls, TRL exposure reduced (P < 0.05) follicle survival, antrum formation rate and follicle diameters at Week 5. While P5 concentrations increased (P < 0.05) following TRL treatment, P4 levels decreased (P < 0.05) in fast-grow follicles at Week 5. Few healthy oocytes were retrieved from antral follicles developed in the presence of TRL. T replacement with TRL increased (P < 0.05) follicle survival and antrum formation at Week 5, compared with TRL alone, to levels comparable to controls. However, high-dose T with TRL decreased (P < 0.05) diameters of fast-grow follicles. Although P4 concentrations produced by fast-grow follicles were not altered by T in the presence of TRL, there was a dose-dependent increase (P < 0.05) in E2 levels at Week 5. High-dose T with TRL decreased (P < 0.05) AMH production by fast-grow follicles at Week 3. More healthy oocytes were retrieved from antral follicles developed in TRL+T compared with TRL alone. DHT had the similar effects to those of high-dose T, except that DHT replacement decreased (P < 0.05) E2 concentrations produced by fast-grow follicles at Week 5 regardless of TRL treatment.

LIMITATION, REASONS FOR CAUTION

This study reports T and DHT actions on in vitro-developed individual primate (macaque) follicles, which are limited to the interval from the secondary to small antral stage.

WIDER IMPLICATION OF THE FINDINGS

The above findings provide novel information on the role(s) of androgens in primate follicular development and oocyte maturation. We hypothesize that androgens promote pre-antral follicle development, but inhibit antral follicle growth and function in primates. While androgens can act positively, excess levels of androgens may have negative impacts on primate folliculogenesis.

STUDY FUNDING/COMPETING INTERESTS

NIH U54 RR024347/RL1HD058294/PL1EB008542 (Oncofertility Consortium), NIH U54 HD071836 (SCCPIR), NIH ORWH/NICHD 2K12HD043488 (BIRCWH), NIH FIC TW/HD-00668, ONPRC 8P51OD011092. There are no conflicts of interest.

Assisted reproductive technology in nonhuman primates

Nonhuman primates (NHP) are the closest animal species to humans and have been widely used for studying human reproductive physiology. Assisted reproductive technology (ART) in Old World NHPs provides great opportunity for studying fertilization, embryo development, embryonic stem cell (ESC) derivation for regenerative medicine, somatic cell nuclear transfer (cloning), and transgenic NHP models of inherited genetic disorders. Here we present two ART protocols developed for rhesus monkey (Macaca mulatta) and baboon (Papio cynocephalus).

Changes in circulating levels and ratios of angiopoietins during pregnancy but not during the menstrual cycle and controlled ovarian stimulation

OBJECTIVE

To determine whether angiopoietin (ANGPT)-1 and -2 are detectable in the circulation of nonhuman primates and women and whether these levels fluctuate in association with ovarian activity.

DESIGN

Prospective.

SETTING

National Primate Research Center, medical center, and infertility clinic.

PATIENT(S)

Adult female rhesus monkeys; 15 women donating oocytes for infertility treatment.

INTERVENTION(S)

Controlled ovarian stimulation with gonadotropins, removal of the corpus luteum and ovaries, oocyte retrieval, and ET.

MAIN OUTCOME MEASURE(S)

Circulating levels of ANGPT-1 and ANGPT-2.

RESULT(S)

Serum ANGPT-1 and ANGPT-2 levels were detectable and invariant in maintaining an ANGPT-1 to -2 ratio >1 in [1] macaques over the course of the natural menstrual cycle, during a controlled ovulation protocol, and after removal of the corpus luteum or ovaries and [2] women undergoing controlled ovarian simulation. In contrast, the ANGPT-1 to -2 ratio was markedly decreased (<<1) at mid-to-late gestation in macaques and in the follicular fluid of women undergoing controlled ovarian simulation because of increased levels of ANGPT-2.

CONCLUSION(S)

The ovary and its dominant structures are not major contributors to circulating levels of ANGPT-1 or ANGPT-2. The physiologic importance of the rising levels of ANGPT-2 after the luteal-placental shift in pregnancy is unknown.

Follicular development induced by recombinant luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in anovulatory women with LH and FSH deficiency: evidence of a threshold effect

OBJECTIVE

To assess the requirement for luteinizing hormone (LH) in women deficient in LH and follicle-stimulating hormone (FSH).

RESEARCH DESIGN AND METHODS

A prospective, randomized, parallel-group, multicentre study was carried out in tertiary care and academic medical centres. Women with anovulatory amenorrhoea > or = 1 year, serum oestradiol (E(2)) < 60 pg/mL (< 220 pmol/L) and low normal serum gonadotrophins were randomized in cycle A to a fixed daily dose of recombinant human (r-h) FSH (150 IU) and r-hLH 0, 25, 75 or 225 IU. Cycles B and C were not randomized.

MAIN OUTCOME MEASURES

Follicular development, ovulation and luteinization.

RESULTS

In cycle A, follicular development was achieved by 63.6% (7/11), 100% (9/9), 72.7% (8/11) and 66.7% (6/9) of patients who received r-hFSH and r-hLH 0, 25, 75 or 225 IU/day, respectively (p = not significant). Among patients with basal serum LH of < 1.2 IU/L, a dose-response relationship of r-hLH to follicular development was observed (p = 0.039). Fourteen of 34 patients (41.2%) wishing to conceive became pregnant. Among patients with hypogonadotrophic hypogonadism (HH) treated with r-hFSH alone, a transition from LH dependence to independence was observed between basal LH values of > or = 1.2 IU/L and < or = 1.6 IU/L. The r-hLH was well tolerated and no serious adverse events occurred during treatment. The most common treatment-related events were related to the reproductive system and the gastrointestinal tract.

CONCLUSIONS

Recombinant human LH provides a safe treatment option for women with HH. This small study also provided evidence suggestive of an LH threshold: follicular development was suboptimal when less than 75 IU/day r-hLH was administered.

Effectiveness of highly purified human menopausal gonadotropin vs. recombinant follicle-stimulating hormone in first-cycle in vitro fertilization–intracytoplasmic sperm injection patients

OBJECTIVE

To compare the effectiveness of highly purified hMG with recombinant FSH (rFSH) in IVF-intracytoplasmic sperm injection patients who were treated with a GnRH agonist.

DESIGN

An open-label, prospective, randomized comparison of fixed gonadotropin regimens.

SETTING

Eighteen Dutch IVF centers.

PATIENT(S)

Six hundred twenty-nine patients who were selected for IVF-intracytoplasmic sperm injection.

INTERVENTION(S)

Patients were randomized to receive either highly purified hMG or rFSH in a fixed dosage of 150 IU/d after GnRH-agonist suppression (long protocol).

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy rate per started cycle. Difference between the two treatment groups was tested by using odds ratios, including the 95% confidence limits (intention-to-treat sample), and by using the Fisher's exact test (per-protocol sample).

RESULT(S)

The ongoing pregnancy rates per started cycle were 26.3% and 25.2% for highly purified hMG and rFSH, respectively (no statistically significant difference). Treatment with highly purified hMG resulted in statistically significantly fewer oocytes (n = 7.8) than did treatment with rFSH (n = 10.6). There were no differences with respect to fertilization rates and implantation rates. Cycles with highly purified hMG were statistically significantly less often canceled as a result of ovarian hyperresponse (2.0% vs. 6.0% for highly purified hMG and rFSH, respectively).

CONCLUSION(S)

Compared with rFSH, highly purified hMG did not result in superiority in ongoing pregnancy rates in first-cycle IVF-intracytoplasmic sperm injection patients who were treated with a fixed dosage of 150 IU of gonadotropin per day. Compared with rFSH, treatment with highly purified hMG resulted in retrieval of fewer oocytes, a lower incidence of hyperresponse, and comparable pregnancy rates.

Priming with progestin, but not GnRH antagonist, induces a consistent endocrine response to exogenous gonadotropins in induced and spontaneously ovulating cats

Ovarian sensitivity to exogenous gonadotropin stimulation (equine chorionic gonadotropin [eCG] and human chorionic gonadotropin [hCG]) following pre-treatment with a progestin (levonorgestrel) versus GnRH antagonist (antide) was studied in cats known to be induced versus spontaneous ovulators. Queens were assigned to one of three treatments: (1) levonorgestrel implants+eCG/hCG (n=7 cats); (2) antide injections+eCG/hCG (n=7) or (3) eCG/hCG alone (control; n=7). Hormonal metabolites were assessed in fecal samples collected daily for 60 days before and during the 37 days inhibitory pre-treatment and for more than 60 days after eCG/hCG. Fecal metabolites of estradiol and progesterone were measured by radioimmunoassay. Females that maintained baseline progesterone were considered induced ovulators, whereas cats that exhibited a luteal phase before inhibition treatment were classified as spontaneous ovulators. Based on fecal hormone profiles, levonorgestrel thoroughly inhibited ovarian activity, whereas antide synchronized follicular phases but did not induce complete ovarian down-regulation. Both treatments prevented ovulation in spontaneous ovulators, but neither caused regression of existing corpora lutea (CL). Levonorgestrel, but not antide, pre-treatment resulted in a quiescent ovary at the time of eCG injection, yet endocrine responses to eCG/hCG were not different among treatments. Interestingly, spontaneously ovulating females exhibited a prolonged estradiol response to gonadotropin stimulation compared to induced ovulators, and this prolonged estradiol surge was replicated by levonorgestrel pre-treatment. Thus, the progestin levonorgestrel effectively suppresses follicular and luteal activity in the cat, resulting in a more consistent response to gonadotropin stimulation, even in females prone to spontaneous ovulation.

Superovulatory response to a low dose single-daily treatment of rhFSH dissolved in polyvinylpyrrolidone in rhesus monkeys

To simplify the procedure for superovulation in the rhesus monkey, this study was designed using polyvinylpyrrolidone (PVP) solution as a solvent for gonadotropins. Thirty-five cycling females (aged 5-8 years old) were divided into six groups during the breeding season (November- February). The groups were as follows: Group I, animals received twice-daily 35 IU recombinant human follicle-stimulating hormone (rhFSH) dissolved in 0.5 ml saline for 8 days as the control; Groups II and III, animals received single-daily 35 IU and 17 IU rhFSH in 0.5 saline, respectively, for 9 days; Groups IV, V and VI, received single-daily injection of 35 IU rhFSH, 17 IU rhFSH and 8.5 IU rhFSH dissolved in 0.5 ml 30% PVP (w/v) solution, respectively, for 9 days. After human chorionic gonadotropin was administered to induce the nuclear maturation of oocytes, oocytes were retrieved and the development competence of recovered oocytes treated with in vitro fertilization were observed. The plasma concentrations of follicle-stimulating hormone and ovarian responses were monitored during the treatment. The results showed that the number of recovered oocytes and the in vitro developmental competence of mature oocytes was equivalent among monkeys when treated with a single-daily treatment of 17 and 35 IU rhFSH with PVP preparation in Groups IV and V compared with the twice-daily 35 IU rhFSH treatments received by Group I. However, almost all animals in Groups II, III and VI responded poorly to corresponding stimulations. These findings indicate that a single-daily low dose of rhFSH dissolved in PVP solution can induce the satisfactory ovarian responses in rhesus monkeys. This has the potential to reduce treatment distress, stress to the animals, the labor of the operator as well as the amount of rhFSH used in ovarian stimulation, compared with traditional superovulation methods.

Effects of rhFSH dose on ovarian follicular response, oocyte recovery and embryo development in rhesus monkeys

The objective was to study the effects of dose of recombinant human follicular stimulating hormone (rhFSH) for ovarian stimulation in rhesus monkeys. Nineteen pubertal and 109 adult female rhesus monkeys were given 37.5, 18, or 9 IU of rhFSH twice-daily for 8 days (total of 600, 300, or 150 IU of rhFSH per cycle, respectively; designated Regimens 1, 2 and 3). Ovarian responses were assessed with ultrasonography, serum concentrations of E2 and FSH, and by in vitro developmental potential (following IVF) of retrieved oocytes. Regimen 1 had more monkeys with very large follicles (diameter>8 mm) than Regimen 2 (P<0.05), which impaired development potential. However, there were no differences between Regimens 1 and 2 in oocyte recovery, whereas Regimen 3 did not elicit superovulation. The developmental potential of embryos obtained from Regimen 2 was higher than that of Regimen 1, as determined by culture to the blastocyst stage in vitro (proportion of blastocysts relative to collected MII oocytes was 55.8% versus 36.8% in pubertal and 63.8% versus 44.2% in adult monkeys; P<0.05 for each), and the results of embryo transfer from Regimen 2 were acceptable. In conclusion, we inferred that the optimal rhFSH dose for ovarian stimulation in rhesus monkeys was a total of 300 IU; this dose should be efficacious for ovarian stimulation as the quality or recovered oocytes was higher and the risk of overstimulation was reduced.

Clinical outcome following stimulation with highly purified hMG or recombinant FSH in patients undergoing IVF: a randomized assessor-blind controlled trial

BACKGROUND

LH activity may influence treatment response and outcome in IVF cycles.

METHODS

A randomized, assessor-blind, multinational trial compared ongoing pregnancy rates (primary end-point) in 731 women undergoing IVF after stimulation with highly purified menotrophin (HP-hMG) (n = 363) or recombinant FSH (rFSH) (n = 368) following a long GnRH agonist protocol. Patients received identical pre- and post-randomization interventions. One or two embryos were transferred on day 3.

RESULTS

More oocytes were retrieved (P < 0.001) after rFSH treatment (11.8) compared with HP-hMG treatment (10.0), but a higher proportion developed into top-quality embryos (P = 0.044) with HP-hMG (11.3%) than with rFSH (9.0%). At the end of stimulation, lower estradiol (E(2)) (P = 0.031) and higher progesterone (P < 0.001) levels were found with rFSH, even after adjusting for follicular response. The distribution of hypo-, iso- and hyper-echogenic endometrium showed a significant (P = 0.023) shift towards the hyperechogenic pattern after rFSH treatment. The ongoing pregnancy rate per cycle was 27% with HP-hMG and 22% with rFSH [odds ratio (95% confidence interval): 1.25 (0.89-1.75)].

CONCLUSION

Superiority of HP-hMG over rFSH in ongoing pregnancy rate could not be concluded from this study, but non-inferiority was established. Pharmacodynamic differences in follicular development, oocyte/embryo quality, endocrine response and endometrial echogenicity exist between HP-hMG and rFSH preparations, which may be relevant for treatment outcome.

Differences in serum LH and FSH levels using depot or daily GnRH agonists in controlled ovarian stimulation: influence on ovarian response and outcome of ART

PURPOSE

To study effects of endogenous LH levels on ovarian response and outcome in ART cycles a controlled study was performed with two patient groups differing in the intensity of pituitary downregulation.

METHODS

Group I (n = 27) received 3.75 mg of the GnRH agonist triptorelin acetate depot, group II (n = 54) was given 0.1 mg triptorelin acetate daily, followed by ovarian stimulation with recombinant FSH.

RESULTS

After downregulation serum LH and FSH levels were significantly lower in group I. Patients of group I needed significantly higher FSH doses to achieve comparable levels of serum estradiol and preovulatory follicles. The number of retrieved oocytes and transferable embryos was lower in group I.

CONCLUSION

Patients with profound endogenous LH suppression by depot GnRH agonists show higher FSH stimulation dose requirements and lower oocyte number and fertilization rate, indicating a need for minimal LH activity in folliculogenesis and oocyte development.

Interactions of macaque blastocysts with epithelial cells in vitro

BACKGROUND

Early in vitro studies of blastocyst formation in several primate species have demonstrated the feasibility of such studies. Initial studies of in vitro-fertilized oocytes cultured with buffalo rat liver cells suggested that other epithelial cells might be used to assess blastocyst adherence and penetration in vitro.

METHODS

Macaque blastocysts were incubated with different epithelial cell lines or with Matrigel. The interaction was studied using light and transmission electron microscopy.

RESULTS

In general, zona-free blastocysts attached 2 days after placing on the substrates. MDCK cells provided optimal conditions for blastocyst development. The best preparations showed some development of an amniotic cavity and distribution of cytotrophoblast and syncytial trophoblast. Distribution of syncytial trophoblast at the margin of the site and cytotrophoblast centrally was similar to that seen at the trophoblastic plate stage in this species. However, there was less syncytial trophoblast than is normally found at this stage, and total time from fertilization to the trophoblastic plate stage was delayed 2 days.

CONCLUSIONS

While in vitro studies with blastocysts cannot completely mimic the intrauterine environment, they can illustrate some of the potential interactions and provide a situation in which parameters may be manipulated.

Overriding follicle selection in controlled ovarian stimulation protocols: quality vs quantity

Selection of the species-specific number of follicles that will develop and ovulate during the ovarian cycle can be overridden by increasing the levels of pituitary gonadotropin hormones, FSH and LH. During controlled ovarian stimulation (COS) in nonhuman primates for assisted reproductive technology (ART) protocols, the method of choice (but not the only method) has been the administration of exogenous gonadotropins, either of nonprimate or primate origin. Due to species-specificity of the primate LH (but not FSH) receptor, COS with nonprimate (e.g., PMSG) hormones can be attributed to their FSH activity. Elevated levels of FSH alone will produce large antral follicles containing oocytes capable of fertilization in vitro (IVF). However, there is evidence that LH, probably in lesser amounts, increases the rate of follicular development, reduces heterogeneity of the antral follicle pool, and improves the viability and rate of pre-implantation development of IVF-produced embryos. Since an endogenous LH surge typically does not occur during COS cycles (especially when a GnRH antagonist is added), a large dose of an LH-like hormone (i.e., hCG) may be given to reinitiate meiosis and produce fertilizable oocytes. Alternate approaches using exogenous LH (or FSH), or GnRH agonist to induce an endogenous LH surge, have received lesser attention. Current protocols will routinely yield dozens of large follicles with fertilizable eggs. However, limitations include non/poor-responding animals, heterogeneity of follicles (and presumably oocytes) and subsequent short luteal phases (limiting embryo transfer in COS cycles). However, the most serious limitation to further improvements and expanded use of COS protocols for ART is the lack of availability of nonhuman primate gonadotropins. Human, and even more so, nonprimate gonadotropins are antigenic in monkeys, which limits the number of COS cycles to as few as 1 (PMSG) or 3 (recombinant hCG) protocols in macaques. Production and access to sufficient supplies of nonhuman primate FSH, LH and CG would overcome this major hurdle.

Strategies for the production of genetically identical monkeys by embryo splitting

Genetically identical rhesus monkeys would have tremendous utility as models for the study of human disease and would be particularly valuable for vaccine trials and tissue transplantation studies where immune function is important. While advances in nuclear transfer technology may someday enable monkeys to be cloned with some efficiency, embryo splitting may be a more realistic approach to creating pairs of genetically identical monkeys. Although several different approaches to embryo splitting, including blastocyst bisection and blastomere separation, have been used successfully in rodents and domestic species for production of pairs and sets of identical offspring, efforts to create monozygotic twins in rhesus monkeys using these approaches have not met with similar success. Aggregation of split embryos with other types of blastomeres, such as tetraploid and developmentally asynchronous blastomeres, that could potentially increase their cell numbers and developmental competence without contributing to term development has been investigated as an alternative approach to creating monozygotic twin monkeys. The major challenges encountered with respect to the efficient production of monozygotic twins in rhesus monkeys and potential strategies to overcome these challenges are discussed.

The primate embryo gene expression resource: a novel resource to facilitate rapid analysis of gene expression patterns in non-human primate oocytes and preimplantation stage embryos

Detailed molecular studies of preimplantation stage development in a suitable nonhuman primate model organism have been inhibited due to the cost and scarcity of embryos. To circumvent these limitations, we have created a new resource for the research community, designated as the Primate Embryo Gene Expression Resource (PREGER). The PREGER sample collection currently contains over 160 informative samples of oocytes, obtained from various sized antral follicles, and embryos obtained through a variety of different protocols. The PREGER makes it possible to undertake quantitative gene-expression studies in rhesus monkey oocytes and embryos through simple and cost-effective hybridization-based methods. The PREGER also makes available other molecular tools to facilitate nonhuman primate embryology. We used PREGER here to compare the temporal expression patterns of five housekeeping mRNAs and three transcription factor mRNAs between mouse and rhesus monkey. We observed noticeable differences in temporal expression patterns between species for some mRNAs, but clear similarities for others. Our results also provide new information related to genome activation and the effects of embryo culture conditions on gene expression in primate embryos. These results provide one illustration of how the PREGER can be employed to obtain novel insight into primate embryogenesis.

Chronic low-dose antiprogestin impairs preimplantation embryogenesis, but not oocyte nuclear maturation or fertilization in rhesus monkeys

Continual administration of low doses of the antiprogestin ZK137316 permits ovarian/menstrual cyclicity, but prevents pregnancy in female rhesus monkeys. The sites of contraceptive action remain unknown. This study determined whether chronic, low-dose antiprogestin exposure during follicular development impairs oocyte maturation in vivo, as well as fertilization and preimplantation embryogenesis in vitro. Adult, female rhesus monkeys exhibiting normal menstrual cycles received vehicle (n=9) or 0.03 mg ZK137316 (n=8)/kg body weight i.m. daily for 3 months. Controlled ovarian stimulation with recombinant gonadotropins was initiated in the 3rd month. Oocytes collected from preovulatory follicles were evaluated for nuclear maturity and inseminated in vitro. Preimplantation embryonic development was monitored in vitro. The total number of oocytes and percentage collected at each nuclear stage were similar in both groups. More (P<0.05) atretic oocytes were recovered following antiprogestin relative to vehicle treatment. Fertilization rates and percentages of embryos that progressed to the morula stage were similar between groups, but antiprogestin-treated females exhibited less (P<0.05) normal cleavage. Embryonic development was accelerated by 1 day (P<0.05) from the 16-cell to the morula stage in the antiprogestin group relative to vehicle. Despite this, the majority of embryos became blastocysts within 6 days in vitro in the antiprogestin group, but fewer expanded (P=0.09) and hatched (P<0.05) compared to vehicle. During in vivo treatment with chronic, low-dose antiprogestin, oocytes retained their ability to resume and complete meiosis as well as fertilize following insemination in vitro. However, preimplantation embryogenesis in vitro was impaired, particularly during the later stages of blastocyst development. Thus, antiprogestin exposure during follicular development altered oocyte functions that are critical for normal preimplantation embryogenesis; this may contribute to pregnancy prevention.

Results of controlled ovarian stimulation for ART in poor responders according to the short protocol using different gonadotrophins combinations

INTRODUCTION

Improving pregnancy rates in intricate cases of ovarian stimulation remains a challenge during IVF and intracytoplasmic sperm injection (ICSI). Different protocols of ovulation induction have been proposed.

METHODS

The short protocol of ovarian stimulation using recombinant follicle-stimulating hormone (rFSH) with or without the use of luteinizing hormone (LH) in IVF or ICSI outcome in patients with many failed attempts and maternity age > or = 37 years was investigated. The prognostic significance of high but normal values of day 3 serum FSH concentrations was also evaluated.

RESULTS

Results show that FSH levels of >9 mIU/ml are associated with poor results even with the use of human menopausal gonadotrophin (HMG). Results were generally comparable when rFSH was used alone or in combination with HMG, except for the quality and the number of embryos transferred, the later being better in the rFSH + HMG group.

CONCLUSION

In conclusion intricate cases have good chances for achieving a pregnancy using the short protocol and the outcome is further improved when LH is added from the beginning of ovarian stimulation. A slight elevation of day 3 FSH seems to be a strong prognostic factor for a poor outcome.

Ovarian stimulation of marmoset monkeys (Callithrix jacchus) using recombinant human follicle stimulating hormone

To reduce the number of animals required for controlled studies of marmoset oocytes and early embryos, a superovulation protocol was developed for the common marmoset. Females were given up to 50 i.u./day recombinant human follicle stimulating hormone (FSH)--(r-hFSH) for 6 days. Ovaries were visualized by a modified laparoscopic technique and follicular aspiration was performed using a needle and suction apparatus inserted directly through an otoscope speculum. The number of follicles + ovulation points (+/- S.E.) was 2.9 (+/- 0.2) in controls and 14.1 (+/- 1.6; P < or = 0.001) in the 50 i.u. r-hFSH per day animals. Oocytes, typically at the germinal vesicle stage at collection, extruded a first polar body within 26 hours. In vitro fertilization was performed and embryos developed to the hatched blastocyst stage (34%). With many high quality oocytes and the ability to synchronize cycles, the marmoset is a valuable primate model for examining nuclear reprograming and early embryonic events.

Use of recombinant FSH and recombinant LH in multiple follicular stimulation for IVF: a preliminary study

Twelve patients (17 cycles) who needed >3000 IU of recombinant FSH (rFSH) on previous follicular stimulation attempts for IVF using rFSH (group A) underwent further attempts (a total of 12 cycles) using rFSH supplemented with rLH from day 7 of stimulation (group B). There was no significant difference in the total quantitative administration of rFSH (mean: 4759 versus 4800 IU rFSH), days of stimulation (14.0 versus 12.6), number of M2 oocytes per patient (3.76 versus 4.17) or embryo morphology between group A and group B respectively. However, there was a significant increase in the incidence of fertilization (60.9 versus 86.0%; P = 0.006) and clinical (ongoing) pregnancies (1 versus 6; P = 0.022). The higher incidence of fertilization increased the mean number of embryos transferred per patient, although in this small group the data was not significant (1.75 versus 2.71). This preliminary clinical trial suggests that in poor responders superimposing rLH upon a down-regulated cycle stimulated with rFSH improves relevant outcome data; and this preliminary trial has encouraged the need for a larger and more detailed study.

Physiology of meiosis-activating sterol: endogenous formation and mode of action

BACKGROUND

In the context of mammalian oocyte maturation, it has been suggested that intermediates of cholesterol biosynthesis may represent the physiological signal that instructs the oocyte to reinitiate meiosis.

METHODS

Endogenous levels of follicular fluid meiosis-activating sterol (FF-MAS) were monitored in rabbit ovarian tissue, and the influence of exogenous gonadotrophins on sterol formation was assessed. The involvement of cAMP in FF-MAS-induced versus spontaneous oocyte maturation in vitro in mice was also investigated, as was the direct microinjection of FF-MAS into mouse oocytes.

RESULTS

Levels of FF-MAS in rabbit ovaries were significantly elevated 1 h after hCG/LH induction and remained so for 4 and 12 h after induction. In naked oocytes undergoing spontaneous maturation, a significant decrease in cAMP was detected after 30 min of culture. However, FF-MAS-mediated induction of oocyte maturation in hypoxanthine-arrested naked oocytes was not associated with any detectable decrease in intracellular cAMP levels. Microinjected FF-MAS failed to induce any noticeable meiosis.

CONCLUSIONS

A rapid increase in FF-MAS level occurred in vivo in the rabbit ovary in response to LH, and clear differences were seen in the cAMP pattern during spontaneous and induced oocyte maturation in mice.

Recombinant follicle-stimulating hormone versus human menopausal gonadotropin in the late follicular phase during ovarian hyperstimulation for in vitro fertilization

OBJECTIVE

To study the effect of exogenous LH in the late follicular phase on ongoing pregnancies and at the different stages of IVF-ET (stimulation, fertilization, and implantation) in patients with low endogenous LH.

DESIGN

Retrospective cohort study with modeling of the different phases of IVF-ET.

SETTING

IVF center of the teaching hospital in Bordeaux, France.

PATIENT(S)

Women undergoing IVF and ICSI treatment.

INTERVENTION(S)

One group received recombinant FSH alone (FSH group) and the other received recombinant FSH and hMG in the late follicular phase (i.e., when the largest follicle reached 14 mm) (FSH/hMG group).

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy, number of oocytes, and number of embryos.

RESULT(S)

The FSH/hMG group had a higher probability of having at least one oocyte (odds ratio [OR] = 2.75 [1.11-6.80]), of having at least one embryo after oocyte retrieval (OR = 2.84 [1.33-6.07]), and of ongoing pregnancy after ET (OR = 2.04 [0.83-5.01]), and globally had a higher probability of ongoing pregnancy (OR = 2.83 [1.19-6.71]).

CONCLUSION(S)

In ovarian hyperstimulation for IVF-ET, LH supplementation in the late follicular phase of women with low endogenous LH is beneficial for ongoing pregnancy by increasing the rate of success of all stages of the treatment.

Efficacy and safety of highly purified menotropin versus recombinant follicle-stimulating hormone in in vitro fertilization/intracytoplasmic sperm injection cycles: a randomized, comparative trial

OBJECTIVE

To demonstrate that highly purified human menopausal gonadotropin (HP-hMG) is as efficient and safe as recombinant FSH in females undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment cycles.

DESIGN

Multinational, open label, randomized, parallel group, comparative phase III trial.

SETTING

In 22 centers across six countries; Belgium (1 center), Germany (6 centers), Israel (6 centers), The Netherlands (2 centers), Switzerland (1 center) and the United Kingdom (6 centers).

PATIENT(S)

A total of 781 women were enrolled between May 1999 and November 2000.

INTERVENTION(S)

In the all-patients-treated population, 373 patients received HP-hMG and 354 received recombinant FSH. A long protocol GnRH agonist regimen was used.

MAIN OUTCOME MEASURE(S)

The primary end point was ongoing pregnancy rate following one IVF/ICSI treatment cycle. Safety was assessed as a secondary end point.

RESULT(S)

Ongoing pregnancy rates 10 weeks after ovum pickup in the per-protocol population were 25% (n = 85/344) in the HP-hMG group and 22% (n = 71/317) in the recombinant FSH group. The incidence of ovarian hyperstimulation syndrome, miscarriage, adverse events, and injection site reactions (tolerability) were similar in both treatment groups.

CONCLUSION(S)

We found HP-hMG to be as effective as recombinant FSH in terms of ongoing clinical pregnancy. Both treatments have a similar safety/tolerability profile.

Sequential culture medium promotes the in vitro development of Macaca fascicularis embryos to blastocysts

In vitro production of blastocyst stage embryos from Macaca fascicularis (Mf) has not previously been demonstrated without cell support. Historical data indicates that a large proportion of Mf embryos arrest at the morula stage in nonsequential culture medium (NSM) lacking serum supplementation and/or cell support. Here we report the application of a sequential culture system supporting in vitro production of Mf blastocysts. Mf embryos produced by in vitro fertilization (IVF; n = 69) were subjected to in vitro culture without cell support in either a commercial sequential embryo culture medium (SM) or an NSM. At 24 hr post-insemination (PI) embryos generated from in vivo and in vitro matured oocytes and cultured in the NSM cleaved to two or more cells in significantly greater proportions (15/23; 65%) compared to embryos cultured in SM (14/46; 30%). However, by day 3 PI embryo development beyond eight cells was not different in NSM (9/23; 39%) compared to SM (25/46; 54%). At day 5 PI embryo development to the morula stage was slightly lower in NSM (8/23, 35%) compared to SM (21/46, 45%), and embryo degeneration was slightly higher in NSM (9/23, 39%) compared to SM (9/46, 20%). After 7-9 days of in vitro culture, embryo development to the blastocyst stage and embryo degeneration were significantly lower and higher, respectively, in NSM (0/23, 0%; and 23/23, 100%) compared to SM (9/46, 20%; and 26/46, 56%). In this study the sequential culture system was better able to support in vitro development of Mf embryos compared to nonsequential culture systems.

Involvement of steroid hormones on in vitro maturation of pig oocytes

The purpose of this study was to determine if the addition of steroid hormones into the culture medium could influence the in vitro maturation of pig oocytes. The cumulus-oocyte complexes (COCs). collected from follicles of 2-5 mm diameter, were matured in steroid-free medium supplemented with various concentrations of estradiol-17beta (0-3000 ng/ml), progesterone (0-5000 ng/ml) and testosterone (0-300 ng/ml). The COCs were cultured for 42 h, then fertilized in vitro. We analyzed nuclear and cytoplasmic maturation with lacmoid stain 20 h after in vitro insemination. We observed no significant effect (P > 0.05) on the percentage of oocytes completing nuclear or cytoplasmic maturation or the number of sperm penetrating each oocyte for any concentration of progesterone, estradiol-17beta or testosterone. Similarly, adding a combination of those hormones to the medium did not significantly (P > 0.05) affect any of the criteria. In order to determine if there was a possible secretion of steroids during maturation, we added COCs, denuded oocytes and stripped cumulus cells to drops of a steroid-free medium and cultured them for 42 h, after which we analyzed the medium, before and after culture, for the presence of progesterone, estradiol-17beta and testosterone by radioimmunoassay (RIA) analysis. COCs, as well as cumulus cells alone, secreted similar amounts of estradiol (43.3 and 37.5 pg/ml, respectively) and progesterone (4.24 and 4.79 ng/ml, respectively) into the maturation medium. A small amount of estradiol (28.8 pg/ml) was also detected when oocytes were cultured alone. These results indicate that no steroids need to be added to the maturation medium of pig oocytes and that the COCs secrete steroids during maturation. It is possible that the amounts produced by the COCs fulfill any requirement for steroids if these steroids are required for either nuclear or cytoplasmic oocyte maturation.

Birth of MHC-defined rhesus monkeys produced by assisted reproductive technology

One of the best animal approaches for testing HIV vaccines is the challenge of vaccinated rhesus macaques with SHIV or SIV. Production of rhesus macaques in which all of the MHC class I and II alleles are known represents an opportunity to characterize the entire immune response to SIV and should be an invaluable resource for understanding pathogenesis and vaccine-induced immune responses. Unfortunately, there are few MHC-defined rhesus macaques available for vaccine research. Selective breeding supports the production of limited numbers of macaques that express particular MHC class I alleles. If both parents express the allele of interest, only three quarters of the offspring will express the same allele. However, assisted reproductive technologies, such as in vitro fertilization (IVF) and embryo transfer, can be used for production of MHC-defined macaques, expressing multiple MHC class I and II molecules for which SIV peptides, tetramers and ELISPOT assays exist. Here, we report the birth of MHC-defined rhesus monkeys produced by assisted reproductive technology. Continued improvements in assisted reproductive technologies in rhesus monkeys will enable us to develop a unique prototypic animal production program for the creation of MHC-defined and genetically-identical monkeys for vaccine research.

The effect of exogenous luteinizing hormone (LH) on oocyte viability: evidence from a comparative study using recombinant human follicle-stimulating hormone (FSH) alone or in combination with recombinant LH for ovarian stimulation in pituitary-suppressed women undergoing assisted reproduction

PURPOSE

The purpose of this prospective, randomized study was to compare ovarian response and oocyte and embryo yields in women undergoing ovulation induction for IVF/ICSI using recombinant human FSH (rhFSH) alone or in combination with recombinant human LH (rhLH).

METHODS

Patients were randomized to receive rhFSH alone (group F; n = 13) or rhFSH + rhLH (group L; n = 15). rhFSH was administered according to a step-down protocol; patients assigned to group L received rhLH at a fixed dose of 75 IU (1 ampoule) throughout the treatment period.

RESULTS

The total dose of rhFSH, number of growing follicles, and serum concentrations of estradiol (E2) on the day of hCG administration were similar in both treatment groups. However, the percentage of metaphase II oocytes and fertilization rate were significantly higher in group F than in group L. The lower fertilization rates associated with rhLH were also seen in a subgroup of patients from group L who had undergone a previous ART cycle stimulated with FSH only and thus acted as their own controls. However, when in vitro fertilization (IVF) and intracytoplasmic sperm injection cycles were considered separately, differences in fertilization rates were statistically significant only for oocytes treated by conventional IVF.

CONCLUSIONS

This study shows that the addition of recombinant LH to recombinant FSH in pituitary-suppressed women undergoing ART does not improve the ovarian response and even may have a negative impact on oocyte maturation and fertilization.

A randomized prospective assessor-blind evaluation of luteinizing hormone dosage and in vitro fertilization outcome

OBJECTIVE

To determine the effect of exogenous LH dosage on IVF outcome.

DESIGN

Single-blinded (assessor-blinded) study with random assignment of treatment groups.

SETTING

Human Assisted Reproduction Unit, Rotunda Hospital, Dublin, Ireland.

PATIENT(S)

Infertile normogonadotropic women undergoing their first cycle of IVF were studied.

INTERVENTION(S)

Patients were randomized to gonadotropin drugs with varying doses of LH per ampule: recombinant FSH containing no LH (group 0, n = 39), urinary FSH containing <1 IU of LH per ampule (group 1, n = 30), hMG containing 25 IU of LH per ampule (group 25, n = 30), and hMG containing 75 IU of LH per ampule (group 75, n = 29). The FSH dose was kept constant at 75 IU per ampule. A long-protocol GnRH-analog regimen was used.

MAIN OUTCOME MEASURE(S)

Dose and duration of gonadotropin stimulation, follicle and oocyte numbers, implantation rate, and pregnancy rate.

RESULT(S)

The median duration of ovarian stimulation; median number of gonadotropin ampules used; serum E2 levels; and numbers of follicles, oocytes, and embryos were similar among the four groups. Median LH levels on the day of hCG administration, however, differed significantly. Live birth rates per cycle differed markedly, but statistical significance was not achieved (23%, 7%, 20%, and 31% for groups 0, 1, 25, and 75, respectively). A significant trend in implantation rates was noted with increasing LH dosage of the urinary preparations (19%, 10%, 18%, and 28% for groups 0, 1, 25, and 75, respectively).

CONCLUSION(S)

In the present study, although the residual endogenous LH after down-regulation was adequate for ovarian response and E2 synthesis, the addition of exogenous LH improved implantation. An FSH/LH ratio of 75/75 IU per ampule appeared to be the optimum dose.

Improving in vitro maturation of oocytes in the human taking lessons from experiences in animal species

One to three per cent of infertile women develop severe ovarian hyperstimulation syndrome after superovulation for assisted reproduction treatment (ART). This severe complication can be avoided when oocytes are obtained at an immature stage (germinal vesicle stage) out of small or medium-sized follicles. This hypothesis has been tested in several infertile women, but clinical pregnancies are disappointlingly low. This new approach in ART is still at an experimental phase and this treatment has still to be improved before routine clinical application. Experimental work in animals and humans suggest a beneficial effect in providing a short preliminary pretreatment with follicle-stimulating hormone to select for a developing cohort of follicles. The aspiration of oocyte cumulus complexes is carried out with a short needle applying reduced aspiration pressure. A crucial point is to provide the appropriate culture environment for the immature oocytes. An optimal cumulus-enclosed human oocyte culture system needs to be defined. The composition of the culture medium could be suggested by in vitro work carried out in animal models. As developmental competence is established during the latest phases of oocyte growth and is dependent on the storage of RNA, a prolonged in vitro maturation period (before inducing nuclear maturation) could provide the necessary transcriptional and translational changes. The conditions to achieve this improved cytoplasmic maturation by prolonging the in vitro culture remain to be defined. More objective noninvasive parameters for oocyte maturity are also needed to pursue research in this field.

Suppression of LH during ovarian stimulation: effects differ in cycles stimulated with purified urinary FSH and recombinant FSH

There has been much debate about the role of luteinizing hormone (LH) during follicle stimulating hormone (FSH)-treated ovarian stimulation for assisted reproduction, where the endogenous LH is suppressed using a gonadotrophin-releasing hormone analogue. The requirement for LH in oestradiol biosynthesis is established, but other effects of 'insufficiency' are less clear, and little attention has been paid to the specific origin of the FSH used. The aim of this study was to examine the roles of profoundly suppressed circulating LH concentrations in cycles of ovarian stimulation for IVF, which were affected in two large separate cohorts of patients undergoing assisted reproduction. They were stimulated by either purified urinary FSH (MHP) or recombinant human FSH (rFSH). Within each dataset, outcomes were examined with respect to the circulating concentrations of LH in the mid-follicular phase, as plasma samples were stored prospectively, and assayed retrospectively. Patients with profoundly suppressed LH showed much reduced oestradiol concentrations at mid-follicular phase and at human chorionic gonadotrophin administration in cycles treated with either MHP or rFSH. However, gross ovarian response, as became evident by FSH dose demands, duration of stimulation, and also oocyte and embryo yields and embryo cryopreservation were influenced only in cycles treated with MHP. Furthermore, no effect upon pregnancy survival was observed. Thus, it is concluded that there is a demand for additional exogenous LH treatment only in cycles treated with purified urinary FSH where the LH is profoundly suppressed.

Follicle-stimulating hormone or human menopausal gonadotropin for ovarian stimulation in in vitro fertilization cycles: a meta-analysis

OBJECTIVE

To reanalyze the results of using FSH alone and hMG during IVF treatment, taking into account the different protocols of administration of superactive GnRH agonist analogs.

DESIGN

Meta-analysis.

SETTING

The London Women's Clinic.

PATIENT(S)

Women undergoing IVF treatment.

INTERVENTION(S)

A meta-analysis of published randomized controlled trials from 1985 to 1999 of the use of FSH versus hMG for ovarian stimulation during IVF treatment. The common Peto odds ratio was calculated with use of a fixed effect model. The overall log odds ratio was estimated after demonstrating the consistency or homogeneity of the study results.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy rate per cycle of IVF.

RESULT(S)

The results suggested that in the "long and short GnRH agonists protocol" of IVF, FSH, and hMG were equally effective in achieving ovarian stimulation, and there were no differences in the clinical pregnancy rates per cycle of IVF. However, in protocols where no pituitary desensitization was used, FSH alone was more efficacious.

CONCLUSION(S)

The optimum choice of gonadotropin preparation for ovarian stimulation during IVF treatment is influenced by the regimen of pituitary desensitization used. The optimum gonadotropin to be used when GnRH antagonists are used has yet to be determined.

A macaque model for studying mechanisms controlling oocyte development and maturation in human and non-human primates

A model to study mechanisms controlling nuclear and cytoplasmic maturation of primate oocytes is being developed in our laboratory. The high incidence of pregnancy failure in women following in-vitro fertilization (IVF) may be partly attributed to inadequate cytoplasmic maturation of oocytes. Advancement of knowledge of mechanisms controlling primate oocyte maturation would have important implications for treatment of human infertility, and would potentially increase numbers of viable non-human primate embryos for biomedical research. Use of a non-human primate model to study oocyte and embryo biology avoids legal, ethical and experimental limitations encountered in a clinical situation. Using this model, the meiotic and developmental capacity of oocytes from three sources have been compared: (i) in-vivo matured oocytes from monkeys stimulated with follicle-stimulating hormone (FSH) and human chorionic gonadotrophin, (ii) in-vitro matured oocytes from monkeys primed with FSH, and (iii) in-vitro matured oocytes from non-stimulated monkeys. This work demonstrates that oocyte developmental competence is likely acquired both during follicle development, before meiotic resumption, and during meiotic progression, concurrent with nuclear maturation. Potential causes of developmental failure of in-vitro matured oocytes, implications for human infertility, and future strategies to study the regulation of primate oocyte maturation are discussed.

The role of luteinizing hormone in folliculogenesis and ovulation induction

OBJECTIVE

To review the physiologic, pathophysiologic, and clinical roles of LH in follicle and oocyte development and maturation and to assess the effects of LH content in exogenous gonadotropin preparations used for ovulation induction.

DESIGN

Critical review of the scientific literature devoted to folliculogenesis. Evaluation of comparison studies that used different gonadotropin preparations for ovulation induction.

CONCLUSION(S)

Folliculogenesis and oocyte maturation are complex processes that require the action of both LH and FSH. Luteinizing hormone is essential to provide the androgen substrate for estrogen synthesis, which in turn contributes to oocyte maturation and may play a relevant role in optimizing fertilization and embryo quality. Although the excessive LH secretion that is present in some disorders is detrimental to reproductive function, this is not applicable to ovulation induction with hMG because this menotropin does not increase daily plasma LH levels. The results of ovulation induction with hMG or FSH-only regimens did not differ in studies conducted in patients with polycystic ovary syndrome and in most studies conducted in ovulatory women undergoing assisted reproductive techniques; conversely, hMG was clearly superior to purified FSH for the treatment of hypogonadotropic hypogonadism. Miscarriage rates were not affected by the use of hMG. Thus, low but detectable LH concentrations positively influence the outcome of ovulation induction in patients with ovulatory disorders and women undergoing assisted reproductive techniques.

Ovarian follicular dynamics: from basic science to clinical practice

The management of low responders (LR) to ovarian stimulation in cycles of assisted reproduction (AR) is a difficult challenge. Aging of the ovary and LR are coincidental in many situations, but LR is also present in young patients undergoing AR. In fact, today it is a recognized cause of infertility. When the aged ovary is considered, there is evidence that the functioning of the granulosa cells as well as the quality of the oocytes and resulting embryos are affected. Similarly, in young LR, the production of inhibin is affected. However, there is no evidence that the quality of the oocyte and/or the resulting embryo is affected. In this study, we have retrospectively analyzed our files and observed that the quality of the oocytes and embryos was similar between younger and older LR and normal responders (NR). Studies using color Doppler vaginal ultrasound have shown that the pulsatility index (PI) and the resistance index (RI) were increased in LR as compared with NR, suggesting that there was some degree of vascular resistance to flow. Treatment of LR is also a difficult challenge. Ovum donation is a successful treatment for LR, since cumulative birth rates are > 85% with four attempts of embryo transfer. The future may be promising for LR once new technologies are introduced into clinical practice. The use of recombinant gonadotropins and genetically engineered human gonadotropin derivatives may be of considerable help for LR. Similarly, non-gonadotropin hormones, such as cytokines or growth factors, may be shown to play a role in the stimulation of the ovary in the near future, and may therefore open new frontiers for treatment of LR.

Regulation of the human menstrual cycle

Our understanding of the regulation of the menstrual cycle has recently improved with the development of various tools of investigation. The cycle is now thought to be determined mainly by the ovary itself, which sends various signals to the pituitary and the hypothalamus. The aim of the cycle is to produce a single mature oocyte each month from puberty to menopause. However, the most common evolution of a follicle is atresia, a consequence of the genetically controlled, ovarian apotosis (or "programmed cell death"). Follicular growth and maturation are mostly independent of gonadotropins, from the stage of primordial follicles to antral follicles. A complete intraovarian paracrine system is implied in this gonadotropin-independent follicular growth, and in the modulation of the actions of the gonadotropins in the ovary. FSH allows the rescue of a minority of follicles from atresia and is indispensable to only the final maturation of the preovulatory follicle. The cyclical variations of the gonadotropins are under the control of ovarian steroids (estradiol and progesterone) and peptides (inhibin). The cycle length is determined by follicular growth and by the fixed life span of the corpus luteum. The mechanism of action of gonadotropins is much better understood since the gonadotropins and their receptor cDNA have been cloned. The recent description of naturally occurring mutations has lead to a better understanding of the role of each gonadotropin, demonstrating the crucial role of FSH in the terminal maturation of the follicles. The ovarian cycle can also be monitored at the level of target tissues of steroids such as the endometrium. The cellular mechanisms of endometrial maturation, under the control of estradiol and progesterone, are better understood. The endometrial maturation is synchronized to follicular development and allows implantation of the conceptus. The genes implied in the implantation of the embryo are being identified (e.g., integrins). Last but not least, the mechanisms of endometrial shedding are being elucidated, especially the role of metalloproteases and angiogenic factors. These concepts will allow the development of new treatments for infertility, the design of new contraceptive techniques, and a better tolerance of treatments using sex steroids, particularly progestin-only pill.

Implications of using follicle-stimulating hormone preparations depleted of luteinizing hormone to achieve follicular growth in in vitro fertilization

We aimed to compare the outcome of in vitro fertilization (IVF) treatment using follicle-stimulating hormone (FSH) containing gonadotropins with human menopausal gonadotropin (hMG) containing gonadotropins for ovarian stimulation. A retrospective analysis of 82 patients undergoing IVF in a private fertility clinic was performed over a specific period of time. Eighteen women received hMG, 20 received Normegon and 44 received FSH. In addition, 17 of these patients received hMG in one cycle and FSH in the other. The main outcome measures studied were duration of treatment, dose of gonadotropins required to achieve optimum follicular growth, number and size of follicles, endometrial thickness, serum estradiol concentrations, number of oocytes retrieved, pregnancy rates and the incidence of ovarian hyperstimulation syndrome (OHSS). At the time of administration of human chorionic gonadotropin (hCG), the mean (+/- SD) serum estradiol concentrations in patients treated with preparations containing FSH and luteinizing hormone (LH) in a ratio of 1:1 was 10,044.3 +/- 5378.8 pmol/l compared with 6819.5 +/- 2597.9 pmol/l in patients treated with preparations with FSH and LH in a ratio of 3:1 and 7369 +/- 4300 pmol/l in patients treated with FSH. The differences between the first and the second two groups were significant (p < 0.05). Endometrial thickness in the three groups of patients were 11 +/- 1.7 mm, 11 +/- 1.5 mm and 9.7 +/- 1.5 mm, respectively (p < 0.001). Comparing cycles of treatment with hMG and FSH in the same patient, we found significantly higher estradiol levels, thicker endometrium, more developing follicles and a shorter duration of treatment in the hMG-treated cycles compared with those in FSH-treated cycles. However, there were no differences between the incidence of OHSS or the pregnancy rates between the three treatment groups. With the advent of recombinant human FSH and the shortage of LH-containing preparations, it is important to note that serum estradiol concentrations on the day of administration of hCG underrepresent the degree of follicular maturation. In the context of the use of a 'long' protocol of gonadotropin-releasing hormone (GnRH) analog therapy and LH-depleted gonadotropin preparations, serum estradiol is no longer a reliable marker of follicle development.

Primate embryonic stem cells

Primate embryonic stem (ES) cells are derived from preimplantation embryos, have a normal karyotype, and are capable of indefinite, undifferentiated proliferation. Even after culture for more than a year, primate ES cells maintain the potential to differentiate to trophoblast and derivatives of embryonic endoderm, mesoderm, and ectoderm. In this review, we compare the characteristics of ES cell lines from two primate species, the rhesus monkey (Macaca mulatta) and the common marmoset (Callithrix jacchus), with the characteristics of mouse ES cells and human embryonal carcinoma cells. We also discuss the implications of using primate ES cells to understand early human development and discuss the practical and ethical implications for the understanding and treatment of human disease.

Follicular dominance and oocyte maturation

The ovulatory follicle has the dual role of releasing a viable oocyte capable of fertilisation and the production of key endocrine signals that result in mating behaviour, the induction of the preovulatory LH surge and ovulation. Further, following ovulation the ovulatory follicle must be capable of forming a viable corpus luteum if pregnancy is to be maintained. Follicle growth is therefore a developmental process during which the follicle progressively acquires a number of properties, each of which is an essential prerequisite for further development. Failure to acquire these properties at the correct time and in an exact sequence will lead to failure of the developmental process and to the deterioration of the follicle through atresia and degeneration of the oocyte.