Pure FSH alone induces ovulation and subsequent pregnancy in the mouse resulting in fetal development

Effect of ovarian stimulation on developmental speed of preimplantation embryo in a mouse model

Ovarian stimulation protocols are widely used to collect oocytes in assisted reproductive technologies (ARTs). Although the influence of ovarian stimulation on embryo quality has been described, this issue remains controversial. Here, we analyzed the influence of ovarian stimulation on developmental speed and chromosome segregation using live cell imaging. Female mice at the proestrus stage were separated by the appearance of the vagina as the non-stimulation (-) group, and other mice were administered pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) as the stimulation (+) groups. The cumulus-oocyte complexes from both groups were inseminated with sperm suspensions from the same male mice. Fertilization rates and developmental capacities were examined, and the developmental speed and frequency of chromosome segregation errors were measured by live-cell imaging using a Histone H2B-mCherry probe. The number of fertilized oocytes obtained was 1.4-fold more frequent in the stimulation (+) group. The developmental rate and chromosome stability did not differ between the groups. Image analysis showed that the mean speed of development in the stimulation (+) group was slightly higher than that in the non-stimulation (-) group. This increase in speed seemed to arise from the slight shortening of the 2- and 4-cell stages and third division lengths and consequent synchronization of cleavage timing in each embryo, not from the emergence of an extremely rapidly developing subpopulation of embryos. In conclusion, ovarian stimulation does not necessarily affect embryo quality but rather increases the chances of obtaining high-quality oocytes in mice.

Superovulation with an anti-inhibin monoclonal antibody improves the reproductive performance of rat strains by increasing the pregnancy rate and the litter size

Rats are multiparous rodents that have been used extensively in research; however, the low reproductive performance of some rat strains hampers the broader use of rats as a biomedical model. In this study, the possibility of increasing the litter size after natural mating in rats through superovulation using an anti-inhibin monoclonal antibody (AIMA) was examined. In outbred Wistar rats, AIMA increased the number of ovulated oocytes by 1.3-fold. AIMA did not affect fertilization and subsequent embryonic development, resulting in a 1.4-fold increase in litter size and a high pregnancy rate (86%). In contrast, conventional superovulation by eCG/hCG administration decreased the pregnancy rate to 6-40% and did not increase the litter size. In inbred Brown Norway rats, AIMA increased the litter size by 1.2-fold, and the pregnancy rate increased more than twice (86% versus 38% in controls). AIMA also increased the litter size by 1.5-fold in inbred Tokai High Avoiders and Fischer 344 rats. AIMA increased the efficiency of offspring production by 1.5-, 2.7-, 1.4-, and 1.4-fold, respectively, in the four rat strains. Thus, AIMA may consistently improve the reproductive performance through natural mating in rats, which could promote the use of AIMA in biomedical research.

Beyond the Umbrella: A Systematic Review of the Interventions for the Prevention of and Reduction in the Incidence and Severity of Ovarian Hyperstimulation Syndrome in Patients Who Undergo In Vitro Fertilization Treatments

Ovarian hyperstimulation syndrome (OHSS) is the main severe complication of ovarian stimulation for in vitro fertilization (IVF) cycles. The aim of the current study was to identify the interventions for the prevention of and reduction in the incidence and severity of OHSS in patients who undergo IVF not included in systematic reviews with meta-analyses of randomized controlled trials (RCTs) and assess and grade their efficacy and evidence base. The best available evidence for each specific intervention was identified, analyzed in terms of safety/efficacy ratio and risk of bias, and graded using the Oxford Centre for Evidence-Based Medicine (CEBM) hierarchy of evidence. A total of 15 interventions to prevent OHSS were included in the final analysis. In the IVF population not at a high risk for OHSS, follitropin delta for ovarian stimulation may reduce the incidence of early OHSS and/or preventive interventions for early OHSS. In high-risk patients, inositol pretreatment, ovulation triggering with low doses of urinary hCG, and the luteal phase administration of a GnRH antagonist may reduce OHSS risk. In conclusion, even if not supported by systematic reviews with homogeneity of the RCTs, several treatments/strategies to reduce the incidence and severity of OHSS have been shown to be promising.

Triggering with 1,500 IU of human chorionic gonadotropin plus follicle-stimulating hormone compared to a standard human chorionic gonadotropin trigger dose for oocyte competence in in vitro fertilization cycles: a randomized, double-blinded, controlled noninferiority trial

OBJECTIVE

To assess if triggering with 1,500 IU of human chorionic gonadotropin (hCG) with 450 IU of follicle-stimulating hormone (FSH) induces noninferior oocyte competence to a standard dose of hCG trigger used in in vitro fertilization (IVF). The alternative trigger will be considered noninferior if it is at least 80% effective in promoting oocyte competence.

DESIGN

Randomized, double-blinded, controlled noninferiority trial.

SETTING

Academic infertility practice.

PATIENTS

Women aged 18-41 undergoing IVF with antral follicle count ≥8, body mass index ≤30 kg/m², and no history of ≥2 IVF cycles canceled for poor response were enrolled. Participants with a serum estradiol >5,000 pg/mL on the day of trigger were excluded because of high risk of ovarian hyperstimulation syndrome.

INTERVENTIONS

Participants were randomized to receive an alternative trigger of 1,500 IU of hCG plus 450 IU of FSH or a standard trigger dose of hCG (5,000 or 10,000 IU) for final oocyte maturation.

MAIN OUTCOME MEASURES

The primary outcome was total competent proportion, defined as the probability of 2 pronuclei from an oocyte retrieved. The alternative trigger will be considered noninferior to the standard trigger if a 1-sided 95% confidence interval (CI) of the relative risk (RR) is not <0.8. Secondary outcomes included oocyte recovery and maturity, intracytoplasmic sperm injection fertilization, embryo quality, pregnancy rates, as well as serum and follicular hormones. Secondary outcomes were compared using a 2-sided superiority test. Outcomes were analyzed by intention-to-treat and per-protocol.

RESULTS

A total of 105 women undergoing IVF were randomized from May 2015 to June 2018. The probability of the primary outcome was 0.59 with the alternative trigger and 0.65 with the standard trigger, with a RR of 0.91 and a 1-sided 95% CI of 0.83. Noninferiority of the alternative trigger was demonstrated. Live birthrate from all fresh transfers in the alternative trigger group vs. standard trigger was 46.9 vs. 46.4% (RR, 1.01; 95% CI, 0.62-1.62), respectively. Live birthrate per randomized participant was 48.1% in the alternative trigger group vs. 62.7% with the standard trigger (RR, 0.73; 95% CI, 0.48-1.11). No participants had a failed retrieval.

CONCLUSION

Triggering with 1,500 IU of hCG plus 450 IU of FSH promoted noninferior oocyte competence compared to a standard hCG trigger dose.

TRIAL REGISTRATION

NCT02310919.

Use of anti-inhibin monoclonal antibody for increasing the litter size of mouse strains and its application to i-GONAD

The litter size of mouse strains is determined by the number of oocytes naturally ovulated. Many attempts have been made to increase litter sizes by conventional superovulation regimens (e.g., using equine or human gonadotropins, eCG/hCG but had limited success because of unexpected decreases in the numbers of embryos surviving to term. Here, we examined whether rat-derived anti-inhibin monoclonal antibodies (AIMAs) could be used for this purpose. When C57BL/6 female mice were treated with an AIMA and mated, the number of healthy offspring per mouse increased by 1.4-fold (11.9 vs. 8.6 in controls). By contrast, treatment with eCG/hCG or anti-inhibin serum resulted in fewer offspring than in nontreated controls. The overall efficiency of production based on all females treated (including nonpregnant ones) was improved 2.4 times with AIMA compared with nontreated controls. The AIMA treatment was also effective in ICR mice, increasing the litter size from 15.3 to 21.2 pups. We then applied this technique to an in vivo genome-editing method (improved genome-editing via oviductal nucleic acid delivery, i-GONAD) to produce C57BL/6 mice deficient for tyrosinase. The mean litter size following i-GONAD increased from 4.8 to 7.3 after the AIMA treatment and genetic modifications were confirmed in 80/88 (91%) of the offspring. Thus, AIMA treatment is a promising method for increasing the litter size of mice and may be applied for the easy proliferation of mouse colonies as well as in vivo genetic manipulation, especially when the mouse strains are sensitive to handling.

Comparison of Oocyte Maturation Trigger Using Follicle Stimulating Hormone Plus Human Chorionic Gonadotropin versus hCG Alone in Assisted Reproduction Technology Cycles

Background

The goal of this study was to investigate oocyte maturation, fertilization and pregnancy rates among infertile women, by concomitant follicle stimulating hormone (FSH) administration at the time of human chorionic gonadotropin (hCG) trigger, compared to hCG trigger alone.

Materials and Methods

In this prospective randomized controlled trial, 109 infertile women between the ages of 20 and 40 years, received gonadotropin-releasing hormone (GnRH) antagonist and fresh embryo transfer. Following the procedure, the subjects were randomly divided into two groups on the oocyte-triggering day. In the experimental group, final oocyte maturation was achieved by 5000 IU hCG plus 450 IU FSH. In the control group, however, oocyte triggering was performed by 5000 IU hCG, only. The primary outcome was clinical pregnancy and the secondary out- comes included oocyte recovery rate, oocyte maturity rate, fertilization proportion rate, fertilization rate, implantation rate and chemical pregnancy rate.

Results

Fifty-four women were appointed to the group with the FSH bolus injection at the time of hCG trigger and 55 women were assigned to the hCG alone group. Women in the FSH group had a significantly higher metaphase II (MII) oocyte (7.17 ± 3.50 vs. 5.87 ± 3.19), 2 pronuclear embryos (2PNs) (5.44 ± 3.20 vs. 3.74 ± 2.30) and total em- bryos (4.57 ± 2.82 vs. 3.29 ± 2.13) compared to hCG alone group, respectively. Furthermore, fertilization rate (0.75 ± 0.19 vs. 0.68 ± 0.25), implantation rate (14.2 vs. 8.5%) as well as clinical (27.9 vs. 15.9%) and chemical (32.6 vs. 20.5%) pregnancy rates were higher in the FSH group, but no statistically significant difference was found (P>0.05).

Conclusion

Combination of FSH and hCG for oocyte triggering improves oocyte maturity and fertilization propor- tion rates without increasing the chance of implantation, chemical and clinical pregnancy rates (Registration number: IRCT2017082724512N5).

A novel oocyte maturation trigger using 1500 IU of human chorionic gonadotropin plus 450 IU of follicle-stimulating hormone may decrease ovarian hyperstimulation syndrome across all in vitro fertilization stimulation protocols

PURPOSE

Modification of the trigger used to induce final oocyte maturation in in vitro fertilization (IVF) is a major strategy used to reduce the risk of ovarian hyperstimulation syndrome (OHSS). A novel trigger composed of 1500 IU of human chorionic gonadotropin (hCG) plus 450 IU of follicle-stimulating hormone (FSH) has been developed to reduce OHSS risk. This study compares outcomes of the novel trigger to conventional triggers used in high-risk OHSS patients undergoing IVF.

METHODS

In this retrospective cohort study, IVF cycles at high risk for OHSS based on a serum estradiol > 5000 pg/ml on trigger day conducted between January 2008 and February 2016 were evaluated. Oocyte maturation was induced with the novel trigger (1500 IU hCG plus 450 IU FSH) or a conventional trigger [3300 IU hCG, gonadotropin-releasing hormone agonist (GnRHa) alone, or GnRHa plus 1500 IU hCG]. IVF cycle outcomes were compared. Trigger strategies were examined for associations with OHSS development using logistic regression.

RESULTS

Among 298 eligible IVF cycles identified, there were no differences in oocyte maturation, fertilization, embryo quality, or pregnancy outcomes among all triggers. After adjusting for serum estradiol level and number of follicles, the novel trigger was associated with lower odds of OHSS symptom development compared to the 3300 IU hCG and GnRHa plus hCG 1500 IU triggers (p = 0.007 and 0.04, respectively).

CONCLUSIONS

This study suggests that 1500 IU hCG plus 450 IU FSH may be associated with decreased OHSS symptoms compared to conventional triggers, while producing similar IVF and pregnancy outcomes. More important, this novel trigger may provide a superior alternative in down-regulated cycles and in patients with hypothalamic dysfunction where GnRHa triggers cannot be utilized.

Substantiation of ovarian effects of leptin by challenging a mouse model of obesity/type 2 diabetes

The goal of the current was to elucidate if treatment with gonadotrophins and leptin can circumvent infertility in obese mice and to establish whether reproductive effects of leptin are influenced at the hypothalamus-hypophysis or ovarian level by using a leptin deficient mouse model of obesity/type 2 diabetes (ob/ob) treated with leptin. The ovulatory response and the fertilization success were compared with the results obtained in ob/ob dams pretreated with a gonadotrophin-replacement therapy or in two groups (ob/ob and wild-type) of control non-pretreated females. The number of corpora lutea was significantly lower in control ob/ob mice than in wild-type dams. Treatment with gonadotrophin-replacement therapy did not increase significantly the ovulation rate in ob/ob, but the administration of leptin-replacement treatment allowed the authors to obtain a number of corpora lutea and oocytes/zygotes similar to those obtained in wild-type females. Furthermore, the leptin supply succeeded in producing fertilized zygotes, although in a lower number than found in the wild-type control. Thus, the hypogonadotrophic state in obese mice may be circumvented by the administration of a gonadotrophin-replacement therapy combined with a protocol for controlled ovarian stimulation, but fertile ovulations are only obtained after applying leptin-replacement therapy. Current results strongly support the existence of direct local effects of leptin on the ovary.

Hormonal induction of ovulation stimulates atresia of antral follicles in a vespertilionid bat, Scotophilus heathi

Scotophilus heathi is a seasonally monoestrous subtropical vespertilionid bat found at Varanasi, India. Although the antral follicles remain present in the ovaries of S. heathi from November till March, ovulation is delayed in this species until early March. In order to understand the mechanism of ovulation suppression during this period of delayed ovulation, the effects of human chorionic gonadotropin (hCG), pregnant mare's serum gonadotropin (PMSG), follicle stimulating hormone (FSH) and gonadotropin releasing hormone agonist (GnRH agonist) on ovarian morphology and steroid concentration were investigated. Hormonal treatments were given as a single i.p. dose 24 h after capture. The bats were sacrificed 48 h after the injection. Treatment with hCG, PMSG, FSH and GnRH agonist failed to induce ovulation in S. heathi, although these hormones produced a high degree of ovarian stimulation. The administration of hCG and PMSG induced ovarian enlargement, intense hyperemia, marked changes in the interstitial cells (ICs), development of several antral follicles and a varying degree of abnormalities in the oocytes of most of the antral follicles. In the bats treated with hCG, PMSG and GnRH agonist, androstenedione concentration increased significantly to extraordinarily high levels, whereas estradiol concentration decreased. Administration of FSH caused regression of ICs and pyknosis of granulosa cells in the majority of antral follicles. FSH did not enhance androstenedione concentration. The results of the present study suggest that the failure of hormonal treatments to induce ovulation during the period of delayed ovulation might be due to a seasonal desensitization of ovarian follicles in S. heathi. The hormonal treatment instead stimulated the ICs to produce a high level of androstenedione resulting in atretic changes of the antral follicles.

Effects of recombinant human follicle-stimulating hormone on embryo development in mice

We have developed a protocol using recombinant human follicle-stimulating hormone (rhFSH) to induce ovarian stimulation in the mouse to investigate its impact on preimplantation embryo development. Embryos were collected from adult female C57Bl/6 x CBA F1 mice treated with rhFSH (0, 2.5, 5.0, 10.0, or 20.0 IU) or 5 IU equine chorionic gonadotropin (eCG). Embryos were also recovered from nontreated control mice. Embryos were cultured in vitro for 88 h, and the stage of development was morphologically assessed. The allocation of cells to the inner cell mass or trophectoderm of blastocysts was determined by differential nuclear staining. The expression of insulin-like growth factor 2 (IGF-II), the insulin-like growth factor receptor (IGF-II receptor), and vascular endothelial growth factor (VEGF) in blastocysts was measured by real-time RT-PCR. Blastocyst development was reduced in the 10 (72.3 +/- 5.1%) and 20 (77.3 +/- 5.6%) IU rhFSH groups compared with control embryos (96.7 +/- 1.0%). The number of inner cell mass cells was reduced (P < 0.001) in the 5, 10, and 20 IU rhFSH groups and the eCG group compared with control embryos. We did not find any effect of rhFSH treatment on IGF-II, IGF-II receptor, or VEGF expression in blastocysts compared with the control group. eCG treatment, however, significantly increased the expression of IGF-II in blastocysts. These results indicate that ovarian stimulation with rhFSH impairs the in vitro development of preimplantation mouse embryos, and these results may have potential implications for clinical ovarian stimulation during infertility treatment and subsequent embryo quality.

Administration of low-dose LH induces ovulation and prevents vascular hyperpermeability and vascular endothelial growth factor expression in superovulated rats

The administration, to rats, of a combination of pregnant mares serum gonadotrophin (PMSG) and human chorionic gonadotrophin (hCG) in high doses induces the ovarian hyperstimulation syndrome (OHSS) which is characterized by increased vascular permeability (VP) and simultaneous overexpression of vascular endothelial growth factor (VEGF) in ovarian cells. hCG has a longer half-life than LH and a greater biological activity, expressed in a higher incidence of complications such as OHSS. Similarly, FSH may also be related to the ovulatory changes within the follicle as there is a simultaneous surge in spontaneous cycles. The aim of this study was to compare the capacity of hCG, FSH and LH to induce ovulation and simultaneously prevent OHSS in the animal model. Immature female rats were treated with 10 IU PMSG for 4 days, and ovulation was triggered with saline, 10 IU hCG, 10 IU FSH, 10 IU LH or 60 IU LH. The number of oocytes ovulated into the tubes, VP and mRNA VEGF expression were evaluated and compared.

All the hormones employed were as effective at triggering ovulation, with similar significant P values when compared with the control for which saline was used. The use of 10 IU LH resulted in significantly lower VP and VEGF expression than that seen in the groups treated with 10 IU hCG, 10 IU FSH or 60 IU LH. In conclusion, FSH and hCG, as well as a sixfold increase in LH, displayed similar biological activities, including increased VP due to excessive VEGF expression. The use of lower doses of LH produced similar rates of ovulation, while preventing the undesired changes in permeability. These experiments should therefore encourage clinicians to determine the optimal dose of LH to be employed in women in order to trigger ovulation and, at the same time, avoid the risk of OHSS.

Efffect of recombinant human FSH on ovulation, pregnancy and in vitro fertilization in androgen-sterilized mice

The effect of a new rhFSH, PG-0801, on oocyte quality, ovulation and in vitro fertilization (IVF) was examined in androgen-sterilized mice. Experimental sterility was induced by a single subcutaneous injection of testosterone propionate (TP, 1 mg/head) into 5 day old female mice. Ovulation was generated in the 10 to 13-week old TP-injected mice by a subcutaneous rhFSH injection (1, 5 or 10 IU/head) followed 48 hours later by a second rhFSH injection (1, 5 or 10 IU/head). For comparison, a subcutaneous PMSG (5 IU/head) injection was used for folliculogenesis and a hCG (5 IU/head) injection was used for ovulation. These were administered using the same protocol. The eggs were harvested from the oviducts and counted 17 to 20 hours after the second injection. IVF was performed by adding sperms (2 x 10(5)/ml to 2 x 106/ ml) to determine the functional activity of the eggs, and the fertilization rate was measured. In addition, the pregnancy rate and fetal development were examined after 15-17 days of gestation. The number of oocytes recovered from the rhFSH/rhFSH group increased dose-dependently and was slightly higher than that of the PMSG/hCG group. The pregnancy rates of the group receiving 1, 5, and 10 IU of rhFSH/rhFSH were 50%, 66.7%, and 75%, respectively, which were significantly higher than that of the control (untreated) group (0%). The numbers of viable fetuses in the 1, 5, and 10 IU/head of the rhFSH/rhFSH group (8.0 +/- 1.50, 8.9 +/- 1.02, and 8.9 +/- 1.12 fetuses/dam, respectively) were comparable to that of the 5 IU/head PMSG/ hCG group (9.4 +/- 0.94). The mice receiving rhFSH/rhFSH and PMSG/hCG showed similar fertilization rates (around 65%) via the IVF procedure. These results demonstrate that a new rhFSH, PG-0801, may be useful for inducing ovulation in functionally infertile patients and for superovulation in ovulatory patients participating in assisted reproductive technology (ART) programs.

Effect of gonadotrophin dose on oocyte retrieval in superovulated BALB/c mice

Mice are commonly used animal models in reproductive and developmental research. In order to get satisfying results from such experiments, large numbers of ova must be available and this can be achieved by using various ovulation induction protocols. To obtain an optimal response from these stimulation protocols, parameters such as breeding-housing conditions of the animal strains, the best age for superovulation, and type and dose of gonadotrophins must be optimized. The aim of this study was to investigate the impact of exogenous stimulation with increasing amounts of gonadotrophins on the number and quality of oocytes/pre-embryos recovered from outbred BALB/c mice. A dose-response analysis was performed by stimulating prepubescent (21- to 25-day-old) and sexually mature (6 to 8 weeks old) female mice with hMG, which contains equal amounts of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The stimulation dose contained 5, 10, 15, 20, 25 or 30 IU of FSH/LH. The effect of increasing stimulation was assessed by monitoring the number and maturity of ova recovered from the tubes. The data were analyzed by using a one-way Anova test and student t-test. Increasing stimulation doses in the prepubescent females resulted in an increased number of ova. A maximum of 55 ova per mouse was reached when stimulating with 20 IU of FSH/LH; higher stimulation doses showed no further increase in oocyte recovery. In the prepubescent group, a maximal number of recovered mature ova was reached with 15 IU of FSH/LH. In the sexually mature female group, 20 IU of FSH/LH gave the best quantitative and qualitative results. Positive effects of copulation on the number and maturity of oocytes in all induction doses were more evident in the prepubescent females and these parameters were significantly more improved (P < 0.05) in this group when compared to the pubertal females. Our findings led to the conclusion that ovulation induction of prepubescent outbred BALB/c mice with 15 IU FSH/LH and sexually mature ones with 20 IU FSH/LH give the best results in terms of oocyte number and maturity.

Endocrine and paracrine control of oocyte development

The effects of gonadotropins on oocyte development are mediated through a variety of mechanisms, including production by granulosa cells of growth factors, cytokines, inhibins, activins, and steroids. Specific receptors for steroids, growth factors, and cytokines have been demonstrated on oocytes of several species. Gonadotropin modulation of follicular concentrations of these paracrine factors may ultimately be responsible for the precise regulation of oocyte function. As gonadotropin-releasing hormone antagonists and recombinant gonadotropins become available, the clinical use of more precise control of the endocrine, paracrine, and autocrine regulation of follicle growth and oocyte development can be more thoroughly investigated.

Superovulation before IVF by recombinant versus urinary human FSH (combined with a long GnRH analog protocol): a comparative study

PURPOSE

Gonal-F (Serono, Aubonne, Switzerland) is a recombinant human follicle stimulating hormone (FSH) synthesized in vitro by cells into which genes encoding for FSH subunits have been inserted. This preparation exhibits physiochemical, immunological, and pharmacological properties that bear great similarity to those of native human FSH. It has a high specific activity and can be administered subcutaneously. To compare the efficacy and safety of Gonal-F with those of urinary human FSH (Metrodin; Serono) in achieving superovulation for IVF purposes in a prospective, randomized study.

METHODS

Twenty infertile patients (normo-ovulatory healthy women) were recruited for the study and allocated at random to the Gonal-F or Metrodin groups. The treatment protocol consisted of pituitary down regulation by GnRH analog (Buserelin; Hoechst, Frankfurt, Germany) employing the "long" protocol initiated at the mid-luteal phase (900 micrograms/day, intranasal administration). Gonal-F (SC) or Metrodin (IM) was injected daily (225 IU/day) starting on cycle day 3. Dose adjustment was performed, when necessary, from cycle day 7.

RESULTS

Of the 20 cycles analyzed, none was canceled due to poor response. No cases of adverse effects (including local intolerance) or ovarian hyperstimulation syndrome were recorded in either group. They did not differ significantly in the following treatment-dependent variables: hormone profile, duration of FSH treatment, total FSH dose required to achieve follicular maturation, and the number of oocytes retrieved, fertilized, and replaced.

CONCLUSIONS

These preliminary data concur with previous studies in demonstrating that Gonal-F is as effective and safe as Metrodin (when given in combination with a "long" protocol of GnRH analog) in inducing controlled ovarian hyperstimulation for IVF purposes. Its mode of administration (SC instead of IM) offers an additional advantage over the urinary human FSH.