Luteinizing hormone and human chorionic gonadotropin: a review of their varied clinical applications in assisted reproductive technology

Impacts of type 1 diabetes mellitus on male fertility and embryo quality in superovulated mice

OBJECTIVE

We aimed to compare embryo quality, sperm morphology, motility, and fertilization obtained from male mice with type 1 diabetes mellitus (T1DM) induced by streptozotocin (STZ) in control and diabetic mice undergoing in vitro fertilization (IVF).

METHODS

CD-1 male mice were divided into control and DM groups, with an i.p. injection of 100 mg/kg STZ to induce T1DM. One month later, the mice were euthanized to investigate the effects of STZ-induced T1DM on the reproductive system. Sperms were obtained from the epididymis and vas deferens. The morphology and motility of the cells were evaluated. Follicle development was stimulated by controlled ovarian stimulation, and oocytes were collected by extracting oviducts and ovaries from female mice housed under controlled environmental conditions with ad libitum access. Both groups underwent IVF with fertilized zygotes followed up until the third day before embryo quality was compared.

RESULTS

Female mice bred with diabetic males exhibited significantly lower fertilization rates than the controls (p < 0.05). Sperm from diabetic mice displayed abnormalities in shape and movement, with reduced motility and fertilization. Embryos from male diabetic mice exhibited a higher incidence of developmental arrest during early embryogenesis. Although no significant differences in oocyte quality were observed, embryos from diabetic mice exhibited higher growth rates. These findings highlighted the T1DM's detrimental effects on sperm morphology, motility, fertilization, and early embryonic development, thus contributing to our understanding of reproductive complications.

CONCLUSION

In conclusion, our findings demonstrated that T1DM significantly impaired sperm morphology, motility, and fertilization capacity, leading to reduced embryo quality and increased developmental arrest. These results highlight the detrimental impact of DM on male reproductive potential and underscore the importance of glycemic control in optimizing outcomes in assisted reproductive techniques such as IVF.

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.

First-in-human trial assessing the pharmacokinetic-pharmacodynamic profile of a novel recombinant human chorionic gonadotropin in healthy women and men of reproductive age

The purpose of this first-in-human trial was to examine the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of a novel recombinant human chorionic gonadotropin (rhCG; FE 999302, choriogonadotropin beta) to support its clinical development for various therapeutic indications. The single and multiple dose PK of choriogonadotropin beta (CG beta) were evaluated in women and the single dose PK and PD of CG beta were compared to those of CG alfa in men. CG beta was safe and well-tolerated in all 84 healthy subjects. In women, the area under the curve (AUC) and the peak serum concentration (C_max ) increased approximately dose proportionally following single and multiple doses of CG beta. The apparent clearance (CL/F) was ~ 0.5 L/h, the mean terminal half-life (t_½ ) ~ 45 h and the apparent distribution volume (V_z /F) ~ 30 L. After single administration in men, the mean AUC was 1.5-fold greater for CG beta than for CG alfa. Mean C_max and V_z /F were comparable for the 2 preparations. In accordance with the differences in AUC, the CL/F was lower for CG beta (CL/F 0.5 vs. 0.8 L/h), explained by a longer t_½ (47 vs. 32 h). Serum testosterone levels induced by a single dose rhCG reflected the PK profiles with a slight delay, resulting in 59% higher AUC for CG beta. The PK parameters for CG beta were comparable in men and in women. In conclusion, the PK differs between the two rhCG preparations, causing higher exposure and a higher PD response for CG beta, which may require relatively lower therapeutic doses.

Recent advances in understanding gonadotropin signaling

Gonadotropins are glycoprotein sex hormones regulating development and reproduction and bind to specific G protein–coupled receptors expressed in the gonads. Their effects on multiple signaling cascades and intracellular events have recently been characterized using novel technological and scientific tools. The impact of allosteric modulators on gonadotropin signaling, the role of sugars linked to the hormone backbone, the detection of endosomal compartments supporting signaling modules, and the dissection of different effects mediated by these molecules are areas that have advanced significantly in the last decade. The classic view providing the exclusive activation of the cAMP/protein kinase A (PKA) and the steroidogenic pathway by these hormones has been expanded with the addition of novel signaling cascades as determined by high-resolution imaging techniques. These new findings provided new potential therapeutic applications. Despite these improvements, unanswered issues of gonadotropin physiology, such as the intrinsic pro-apoptotic potential to these hormones, the existence of receptors assembled as heteromers, and their expression in extragonadal tissues, remain to be studied. Elucidating these issues is a challenge for future research.