Effects of Elevated Progesterone Levels on the Day of hCG on the Quality of Oocyte and Embryo

Granulosa cell metabolism at ovulation correlates with oocyte competence and is disrupted by obesity and aging

STUDY QUESTION

Is oocyte developmental competence associated with changes in granulosa cell (GC) metabolism?

SUMMARY ANSWER

GC metabolism is regulated by the LH surge, altered by obesity and reproductive aging, and, in women, specific metabolic profiles are associated with failed fertilization versus increased blastocyst development.

WHAT IS KNOWN ALREADY

The cellular environment in which an oocyte matures is critical to its future developmental competence. Metabolism is emerging as a potentially important factor; however, relative energy production profiles between GCs and cumulus cells and their use of differential substrates under normal in vivo ovulatory conditions are not well understood.

STUDY DESIGN, SIZE, DURATION

This study identified metabolic and substrate utilization profiles within ovarian cells in response to the LH surge, using mouse models and GCs of women undergoing gonadotropin-induced oocyte aspiration followed by IVF/ICSI.

PARTICIPANTS/MATERIALS, SETTING, METHODS

To comprehensively assess follicular energy metabolism, we used real-time metabolic analysis (Seahorse XFe96) to map energy metabolism dynamics (mitochondrial respiration, glycolysis, and fatty acid oxidation) in mouse GCs and cumulus-oocyte complexes (COCs) across a detailed time course in the lead up to ovulation. In parallel, the metabolic profile of GCs was measured in a cohort of 85 women undergoing IVF/ICSI (n = 21 with normal ovarian function; n = 64 with ovarian infertility) and correlated with clinical parameters and cycle outcomes.

MAIN RESULTS AND THE ROLE OF CHANCE

Our study reveals dynamic changes in GC energy metabolism in response to ovulatory LH, with mitochondrial respiration and glycolysis differentially affected by obesity versus aging, in both mice and women. High respiration in GCs is associated with failed fertilization (P < 0.05) in a subset of women, while glycolytic reserve and mitochondrial ATP production are correlated with on-time development at Day 3 (P < 0.05) and blastocyst formation (P < 0.01) respectively. These data provide new insights into the cellular mechanisms of infertility, by uncovering significant associations between metabolism within the ovarian follicle and oocyte developmental competence.

LIMITATIONS, REASONS FOR CAUTION

A larger prospective study is needed before the metabolic markers that were positively and negatively associated with oocyte quality can be used clinically to predict embryo outcomes.

WIDER IMPLICATIONS OF THE FINDINGS

This study offers new insights into the importance of GC metabolism for subsequent embryonic development and highlights the potential for therapeutic strategies focused on optimizing mitochondrial metabolism to support embryonic development.

STUDY FUNDING/COMPETING INTEREST(S)

National Health and Medical Research Council (Australia). The authors have no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Progestin and adipoQ receptor 7 (PAQR7) mediate the anti-apoptotic effect of P4 on human granulosa cells and its deficiency reduces ovarian function in female mice

PURPOSE

PAQR7 plays a key role in cell apoptosis as a progesterone membrane receptor. The physiological mechanism of PAQR7 in ovarian function and its anti-apoptotic action in mammals remain poorly understood.

METHODS

We first added 0.2 µM aminoglutethimide (AG), an inhibitor of endogenous progesterone (P4) secretion, and transfected siPAQR7 co-incubated with P4 in human KGN cells to identify granulosa cell apoptosis, respectively. Additionally, we used Paqr7 knockout (PAQR7 KO) mice to assess the role of PAQR7 in the ovary.

RESULTS

The PAQR7 deficiency significantly increased apoptosis of KGN cells, and this significant difference disappeared following P4 supplementation. The Paqr7-/- female mice showed a prolonged estrous cycle, reduced follicular growth, increased the number of atresia follicles, and decreased the concentrations of E2 and AMH. The litters, litter sizes, and spontaneous ovulation in the Paqr7-/- mice were significantly decreased compared with the Paqr7+/+ mice. In addition, we also found low expression of PAQR7 in GCs from human follicular fluids of patients diagnosed with decreased ovarian reserve (DOR) and ovaries of mice with a DOR-like phenotype, respectively.

CONCLUSIONS

The present study has identified that PAQR7 is involved in mouse ovarian function and fertilization potential. One possible mechanism is mediating the anti-apoptotic effect of P4 on GC apoptosis via the BCL-2/BAX/CASPASE-3 signaling pathway. The mechanism underlying the effect of PAQR7 on ovarian development and aging remains to be identified.

Delayed blastocyst development is influenced by the level of progesterone on the day of trigger

PURPOSE

To evaluate the association between progesterone (P) level on the day of trigger and time to blastulation in IVF cycles.

METHODS

This was a retrospective cohort study with autologous IVF cycles performed at our Institution from January 2019 to December 2021. A total of 1109 IVF cycles were included. The primary outcome was to compare time to blastulation in terms of percentage of expanded (grade 3) blastocysts on day 5 according to progesterone level at trigger.

RESULTS

A total of 3517 blastocysts were analyzed. After dividing progesterone level in quartiles (Q1, P < 0.50 ng/ml; Q2 0.50 ng/ml ≤ P ≤ 0.78 ng/ml; Q3, 0.79 ng/ml ≤ P ≤ 1.15 ng/ml; Q4, P > 1.15 ng/ml), we observed a delay in blastocyst development according to the increasing level of progesterone at trigger (analysis by rank, P-value = 0.01). After adjusting for confounding factors at the multivariate analysis, the percentage of day 5 blastocysts was reduced for Q3 (- 13.8%, 95% CI from - 20.5 to - 7.0%, p < 0.001) and Q4 (- 7.7%, 95% CI from - 15.5 to 0.0%, p = 0.05) compared to Q1 (reference).

CONCLUSIONS

Progesterone levels on day of trigger correlate to the percentage of expanded (grade 3) blastocysts on day 5 and a delayed blastocyst development day 5 is expected for high progesterone levels.

Premature Progesterone Elevation in in vitro Fertilisation Cycles - Current Perspectives

The impact of premature elevation of progesterone (PPE) on the day of the trigger on pregnancy outcome in in vitro fertilisation (IVF) cycles has been a matter of contention and debate for decades. Research over the last 30 years has indicated that PPE >1.5 ng/ml is associated with declining live birth rates following fresh embryo transfer. Freeze-only approach has become a universal solution to overcome the issue of PPE. However, the topic is still mired with controversy. Few studies have not shown a negative impact on pregnancy rates. The impact of PPE on embryological parameters such as oocyte and embryo quality and ploidy is still very controversial. An important contentious issue is the choice of the threshold P value above which it is considered abnormal and a freeze-all strategy would be cost-effective. Currently, though a cutoff of >1.5 ng/ml is widely used, practices are not uniform and varying thresholds from 0.4 to 3 ng/ml are utilised. This review addresses the current understanding of PPE in IVF and the above controversies. The incidence, aetiology and source of progesterone rise, impact on endometrial receptivity, oocyte and embryo quality, impact on live birth and cumulative live birth and impact on frozen embryo transfer and donor oocyte cycles are discussed. Current controversies regarding the optimal threshold, assay performance and future directions are addressed.