Poor oocyte quality rather than implantation failure as a cause of age-related decline in female fertility

Associations between the time interval from myomectomy to subsequent pregnancy and the obstetric outcomes: A population-based cohort study

OBJECTIVE

To investigate the associations between time interval from myomectomy to pregnancy (TIMP) and subsequent pregnancy and obstetric complications, and to explore whether these associations vary according to maternal age at birth.

METHODS

A retrospective population-based cohort study was conducted from 2008 to 2017. Data were extracted from the National Health Insurance Research Database and the Taiwan Maternal and Child Health Database, comprising 2024 379 births from 1 391 856 pregnancies. Eligible cases were identified using diagnostic and procedure codes; 4006 first singleton births in 4006 women after their first laparotomic myomectomy were identified. We estimated the risks of pregnancy and obstetric outcomes according to TIMP (<6, 6-11, and ≥12 months). Subgroup analysis was performed by further dividing according to maternal age at birth (18-34 vs ≥35 years old).

RESULTS

We observed higher risks of gestational hypertensive disorders (adjusted odds ratio [aOR] 1.97, 95% confidence interval [CI] 1.22-3.18, P = 0.005) and neonatal death (aOR 4.59, 95% CI 1.49-14.18, P = 0.008) for TIMP of <6 months versus TIMP of 6-11 months. Likewise, a TIMP ≥12 months was associated with increased risks of gestational hypertensive disorders (aOR 1.72, 95% CI 1.14-2.58, P = 0.010), and neonatal death (aOR 3.27, 95% CI 1.16-9.24, P = 0.025) versus a TIMP of 6-11 months. In subgroup analysis, women over 35 years old still had higher risks of gestational hypertensive disorders when TIMP was <6 months (aOR 2.26, 95% CI 1.17-4.37, P = 0.015) or ≥12 months (aOR 2.04, 95% CI 1.17-3.54, P = 0.012), and a higher risk of neonatal death when TIMP was <6 months (aOR 4.05, 95% CI 1.06-15.53, P = 0.041); whereas women aged 18-34 years old did not.

CONCLUSIONS

This study suggests that a TIMP between 6 and 11 months is associated with lower risks of gestational hypertensive disorders and neonatal death compared with a TIMP <6 months or ≥12 months, especially for women over 35 years old.

CPEB3 Maintains Developmental Competence of the Oocyte

Mammalian oocyte development depends on the temporally controlled translation of maternal transcripts, particularly in the coordination of meiotic and early embryonic development when transcription has ceased. The translation of mRNA is regulated by various RNA-binding proteins. We show that the absence of cytoplasmic polyadenylation element-binding protein 3 (CPEB3) negatively affects female reproductive fitness. CPEB3-depleted oocytes undergo meiosis normally but experience early embryonic arrest due to a disrupted transcriptome, leading to aberrant protein expression and the subsequent failure of embryonic transcription initiation. We found that CPEB3 stabilizes a subset of mRNAs with a significantly longer 3'UTR that is enriched in its distal region with cytoplasmic polyadenylation elements. Overall, our results suggest that CPEB3 is an important maternal factor that regulates the stability and translation of a subclass of mRNAs that are essential for the initiation of embryonic transcription and thus for embryonic development.

The close relationship between oocyte aging and telomere shortening, and possible interventions for telomere protection

As women delay childbearing due to socioeconomic reasons, understanding molecular mechanisms decreasing oocyte quantity and quality during ovarian aging becomes increasingly important. The ovary undergoes biological aging at a higher pace when compared to other organs. As is known, telomeres play crucial roles in maintaining genomic integrity, and their shortening owing to increased reactive oxygen species, consecutive cellular divisions, genetic and epigenetic alterations is associated with loss of developmental competence of oocytes. Novel interventions such as antioxidant treatments and regulation of gene expression are being investigated to prevent or rescue telomere attrition and thereby oocyte aging. Herein, potential factors and molecular mechanisms causing telomere shortening in aging oocytes were comprehensively reviewed. For the purpose of extending reproductive lifespan, possible therapeutic interventions to protect telomere length were also discussed.

Enhancing Oocyte Quality in Aging Mice: Insights from Mesenchymal Stem Cell Therapy and FOXO3a Signaling Pathway Activation

Ovarian aging reduced the quality of oocytes, resulting in age-related female infertility. It is reported that mesenchymal stem cells (MSCs) therapy can improve age-related ovarian function decline and the success rate of in vitro maturation (IVM) in assisted reproductive therapy. In order to investigate the effectiveness and mechanisms of MSCs to enhance oocyte quality of cumulus oocyte complexes (COCs) in advanced age, this study focus on the respective functional improvement of oocytes and granulosa cells (GCs) from aging mice and further to explore and verify the possible mechanisms. Here, we studied a popular but significant protein of follicular development, Forkhead box O-3a (FOXO3a), which is a transcription factor that mediates a variety of cellular processes, but the functions of which in regulating oocyte quality in MSCs therapy still remain inconclusive. In this study, the RNA-seq data of metaphase II (MII) oocytes and GCs isolated from COCs confirmed that, GCs of immature follicles show the most potential to be the targeted cells of bone marrow mesenchymal stem cells (BMSCs) by FOXO3a signaling pathway. Furthermore, we demonstrated the effectiveness of BMSCs co-culture with aging COCs to enhance oocyte quality and found its mechanism to function via ameliorating the biological function of GCs by alleviating FOXO3a levels. These results provide significant fundamental research on MSCs therapy on ovarian aging, as well as offering guidance for raising the success rate of assisted reproductive technology such IVM in clinical and non-clinical settings.

Gravidity modifies the associations of age and spousal age difference with couple's fecundability: a large cohort study from China

STUDY QUESTION

Do couple's age ranges for optimal fecundability, and the associations with fecundability of couple's age combinations and age differences differ with gravidity?

SUMMARY ANSWER

The couple's age range of optimal fecundability and age combinations differed with gravidity, and gravidity might modify the associations of age and spousal age difference with couple's fecundability.

WHAT IS KNOWN ALREADY

Age is one of the strongest determinants of fecundability, but the existing studies have certain limitations in study population, couple's extreme age combinations and age differences, and have not explored whether the association between age and fecundability differs with gravidity.

STUDY DESIGN, SIZE, DURATION

Retrospective cohort study. 5 407 499 general reproductive-aged couples (not diagnosed with infertility) participated in the National Free Pre-conception Check-up Projects during 2015-2017. They were followed up for pregnancy outcomes through telephone interviews every 3 months until they became pregnant or were followed up for 1 year.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The main outcome was time to pregnancy, and the fecundability odds ratios and 95% CIs were estimated using the Cox models for discrete survival time. The associations of age and spousal age difference with fecundability were evaluated by restricted cubic splines.

MAIN RESULTS AND THE ROLE OF CHANCE

In this large cohort of general reproductive-aged population, the age of optimal fecundability of multigravida couples was older than that of nulligravida couples, but their subsequent fecundability declined more sharply with age. The decline in female fecundability was more pronounced with age, with fecundability dropping by ∼30% in both nulligravida and multigravida couples whose female partners aged ≥35 years. In the nulligravida group, the fecundability of couples who were both ≤24 years with the same age was the highest, which decreased steadily with the increase of spousal age difference, and younger male partners did not seem to contribute to improving couple's fecundability. In the multigravida group, couples with female partners aged 25-34 years and a spousal age difference of -5 to 5 years showed higher fecundability, and the effect of spousal age difference on couple's fecundability became suddenly apparent when female partners aged around 40 years. Young male partners were unable to change the decisive effect of female partner's age over 40 years on couple's reduced fecundability, regardless of gravidity.

LIMITATIONS, REASONS FOR CAUTION

Lacking the time for couples to attempt pregnancy before enrollment, and some couples might suspend pregnancy plans during follow-up because of certain emergencies, which would misestimate the fecundability. Due to the lack of information on sperm quality and sexual frequency of couples, we could not adjust for these factors. Moreover, due to population characteristics, the extrapolation of our results required caution.

WIDER IMPLICATIONS OF THE FINDINGS

The couple's age range of optimal fecundability, age combinations, and spousal age difference on fecundability varied with gravidity. Female age-related decline in fecundability was more dominant in couple's fecundability. Targeted fertility guidance should be provided to couples with different age combinations and gravidities.

STUDY FUNDING/COMPETING INTEREST(S)

This research received funding from the Project of National Research Institute for Family Planning (Grant No. 2018NRIFPJ03), the National Key Research and Development Program of China (Grant No. 2016YFC1000307), and the National Human Genetic Resources Sharing Service Platform (Grant No. 2005DKA21300), People's Republic of China. The funders had no role in study design, analysis, decision to publish, or preparation of the manuscript. The authors report no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Telomere dynamics and reproduction

The oocyte, a long-lived, postmitotic cell, is the locus of reproductive aging in women. Female germ cells replicate only during fetal life and age throughout reproductive life. Mechanisms of oocyte aging include the accumulation of oxidative damage, mitochondrial dysfunction, and disruption of proteins, including cohesion. Nobel Laureate Bob Edwards also discovered a "production line" during oogonial replication in the mouse, wherein the last oocytes to ovulate in the adult-derived from the last oogonia to exit mitotic replication in the fetus. On the basis of this, we proposed a two-hit "telomere theory of reproductive aging" to integrate the myriad features of oocyte aging. The first hit was that oocytes remaining in older women traversed more cell cycles during fetal oogenesis. The second hit was that oocytes accumulated more environmental and endogenous oxidative damage throughout the life of the woman. Telomeres (Ts) could mediate both of these aspects of oocyte aging. Telomeres provide a "mitotic clock," with T attrition an inevitable consequence of cell division because of the end replication problem. Telomere's guanine-rich sequence renders them especially sensitive to oxidative damage, even in postmitotic cells. Telomerase, the reverse transcriptase that restores Ts, is better at maintaining than elongating T. Moreover, telomerase remains inactive during much of oogenesis and early development. Oocytes are left with short Ts, on the brink of viability. In support of this theory, mice with induced T attrition and women with naturally occurring telomeropathy suffer diminished ovarian reserve, abnormal embryo development, and infertility. In contrast, sperm are produced throughout the life of the male by a telomerase-active progenitor, spermatogonia, resulting in the longest Ts in the body. In mice, cleavage-stage embryos elongate Ts via "alternative lengthening of telomeres," a recombination-based mechanism rarely encountered outside of telomerase-deficient cancers. Many questions about Ts and reproduction are raised by these findings: does the "normal" T attrition observed in human oocytes contribute to their extraordinarily high rate of meiotic nondisjunction? Does recombination-based T elongation render embryos susceptible to mitotic nondisjunction (and mosaicism)? Can some features of Ts serve as markers of oocyte quality?

Exploring the knowledge, attitudes, and perceptions of women of reproductive age towards fertility and elective oocyte cryopreservation for age-related fertility decline in the UK: a cross-sectional survey

STUDY QUESTION

What are the knowledge, perceptions and attitudes towards fertility and elective oocyte cryopreservation (OC) for age-related fertility decline (ARFD) in women in the UK?

SUMMARY ANSWER

Awareness of OC for ARFD has reportedly improved compared to studies carried out almost a decade ago, but inconsistencies in knowledge remain regarding the rate of miscarriage amongst specific age groups, the financial costs and optimal age to undergo OC for ARFD.

WHAT IS KNOWN ALREADY

The age of first-time motherhood has increased amongst western societies, with many women of reproductive age underestimating the impact of age on fertility. Further understanding of women's awareness of their fertility, the options available to preserve it and the barriers for seeking treatment earlier are required in order to prevent the risk of involuntary childlessness.

STUDY DESIGN, SIZE, DURATION

A hyperlink to a cross-sectional survey was posted on social media (Instagram) between 25 February 2021 and 11 March 2021.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women from the general population aged 18-50 years were invited to complete the survey.

MAIN RESULTS AND THE ROLE OF CHANCE

In total, 5482 women fulfilled the inclusion criteria and completed the survey. The mean age of participants was 35.0 years (SD 10.25; range 16-52). Three quarters (74.1%; n = 4055) disagreed or strongly disagreed they felt well informed regarding the options available to preserve their fertility, in case of a health-related problem or ARFD. The majority overestimated the risk of miscarriage in women aged ≥30 years old, with 14.5% correctly answering 20%, but underestimated the risks in women ≥40, as 20.1% correctly answered 40-50%. Three quarters (73.2%; n = 4007) reported an awareness of OC for ARFD and 65.8% (n = 3605) reported that they would consider undergoing the procedure. The number of women who considered OC for ARFD across age groups were as follows: 18-25 (8.3%; n = 300), 26-30 (35.8%; n = 1289), 31-35 (45.9%; n = 1654), 36-40 (9.6%; n = 347), 41-45 (0.3%; n = 13), and 46-50 (0.1%; n = 2). The majority of women (81.3%; n = 4443) underestimated the cost of a single cycle of OC for ARFD (<£5000). Furthermore, 10.4% (n = 566) believed a single cycle would be adequate enough to retrieve sufficient oocytes for cryopreservation. Approximately 11.0% (n = 599) believed OC for ARFD may pose significant health risks and affect future fertility. Less than half agreed or strongly agreed that the lack of awareness regarding OC for ARFD has impacted the likelihood of pursuing this method of fertility preservation further (41.4%; n = 2259).

LIMITATIONS, REASONS FOR CAUTION

Results from cross-sectional studies are limited as interpretations made are merely associations and not of causal relationships. The online nature of participant recruitment is subject to selection bias, considering women with access to social media are often from higher socioeconomic and education backgrounds, thus limiting generalizability of the findings.

WIDER IMPLICATIONS OF THE FINDINGS

Further education regarding the financial costs and optimal age to undergo elective OC to increase the chances of successful livebirth are required. Clinicians should encourage earlier fertility counselling to ensure that OC is deemed a preventative measure of ARFD, rather than an ultimate recourse to saving declining fertility.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was required for this article. There are no conflicts of interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

Endometrial receptivity in women of advanced age: an underrated factor in infertility

BACKGROUND

Modern lifestyle has led to an increase in the age at conception. Advanced age is one of the critical risk factors for female-related infertility. It is well known that maternal age positively correlates with the deterioration of oocyte quality and chromosomal abnormalities in oocytes and embryos. The effect of age on endometrial function may be an equally important factor influencing implantation rate, pregnancy rate, and overall female fertility. However, there are only a few published studies on this topic, suggesting that this area has been under-explored. Improving our knowledge of endometrial aging from the biological (cellular, molecular, histological) and clinical perspectives would broaden our understanding of the risks of age-related female infertility.

OBJECTIVE AND RATIONALE

The objective of this narrative review is to critically evaluate the existing literature on endometrial aging with a focus on synthesizing the evidence for the impact of endometrial aging on conception and pregnancy success. This would provide insights into existing gaps in the clinical application of research findings and promote the development of treatment options in this field.

SEARCH METHODS

The review was prepared using PubMed (Medline) until February 2023 with the keywords such as 'endometrial aging', 'receptivity', 'decidualization', 'hormone', 'senescence', 'cellular', 'molecular', 'methylation', 'biological age', 'epigenetic', 'oocyte recipient', 'oocyte donation', 'embryo transfer', and 'pregnancy rate'. Articles in a language other than English were excluded.

OUTCOMES

In the aging endometrium, alterations occur at the molecular, cellular, and histological levels suggesting that aging has a negative effect on endometrial biology and may impair endometrial receptivity. Additionally, advanced age influences cellular senescence, which plays an important role during the initial phase of implantation and is a major obstacle in the development of suitable senolytic agents for endometrial aging. Aging is also accountable for chronic conditions associated with inflammaging, which eventually can lead to increased pro-inflammation and tissue fibrosis. Furthermore, advanced age influences epigenetic regulation in the endometrium, thus altering the relation between its epigenetic and chronological age. The studies in oocyte donation cycles to determine the effect of age on endometrial receptivity with respect to the rates of implantation, clinical pregnancy, miscarriage, and live birth have revealed contradictory inferences indicating the need for future research on the mechanisms and corresponding causal effects of women's age on endometrial receptivity.

WIDER IMPLICATIONS

Increasing age can be accountable for female infertility and IVF failures. Based on the complied observations and synthesized conclusions in this review, advanced age has been shown to have a negative impact on endometrial functioning. This information can provide recommendations for future research focusing on molecular mechanisms of age-related cellular senescence, cellular composition, and transcriptomic changes in relation to endometrial aging. Additionally, further prospective research is needed to explore newly emerging therapeutic options, such as the senolytic agents that can target endometrial aging without affecting decidualization. Moreover, clinical trial protocols, focusing on oocyte donation cycles, would be beneficial in understanding the direct clinical implications of endometrial aging on pregnancy outcomes.

Deciphering reproductive aging in women using a NOD/SCID mouse model for distinct physiological ovarian phenotypes

Female fertility is negatively correlated with age, with noticeable declines in oocyte quantity and quality until menopause. To understand this physiological process and evaluate human approaches for treating age-related infertility, preclinical studies in appropriate animal models are needed. Thus, we aimed to characterize an immunodeficient physiological aging mouse model displaying ovarian characteristics of different stages during women's reproductive life. NOD/SCID mice of different ages (8-, 28-, and 36-40-week-old) were employed to mimic ovarian phenotypes of young, Advanced Maternal Age (AMA), and old women (~18-20-, ~36-38-, and >45-years-old, respectively). Mice were stimulated, mated, and sacrificed to recover oocytes and embryos. Then, ovarian reserve, follicular growth, ovarian stroma, mitochondrial dysfunction, and proteomic profiles were assessed. Age-matched C57BL/6 mice were employed to cross-validate the reproductive outcomes. The quantity and quality of oocytes were decreased in AMA and Old mice. These age-related effects associated spindle and chromosome abnormalities, along with decreased developmental competence to blastocyst stage. Old mice had less follicles, impaired follicle activation and growth, an ovarian stroma inconducive to growth, and increased mitochondrial dysfunctions. Proteomic analysis corroborated these histological findings. Based on that, NOD/SCID mice can be used to model different ovarian aging phenotypes and potentially test human anti-aging treatments.

The failure of gene-centrism

"Challenging the utility of polygenic scores for social science" is a compelling but limited critique. Phenotypic development is sensitive to both initial conditions and all subsequent states - from conception to senescence. Thus, gene-centric analyses are misleading (and often meaningless) because gene products are transformed, and their phenotypic 'effects' combined and attenuated with successive propagations from molecular and cellular contexts to organismal and social environments.

Biomarkers of aging

Aging biomarkers are a combination of biological parameters to (i) assess age-related changes, (ii) track the physiological aging process, and (iii) predict the transition into a pathological status. Although a broad spectrum of aging biomarkers has been developed, their potential uses and limitations remain poorly characterized. An immediate goal of biomarkers is to help us answer the following three fundamental questions in aging research: How old are we? Why do we get old? And how can we age slower? This review aims to address this need. Here, we summarize our current knowledge of biomarkers developed for cellular, organ, and organismal levels of aging, comprising six pillars: physiological characteristics, medical imaging, histological features, cellular alterations, molecular changes, and secretory factors. To fulfill all these requisites, we propose that aging biomarkers should qualify for being specific, systemic, and clinically relevant.

Kunling Wan improves oocyte quality by regulating the PKC/Keap1/Nrf2 pathway to inhibit oxidative damage caused by repeated controlled ovarian hyperstimulation

ETHNOPHARMACOLOGICAL RELEVANCE

Kunling Wan (KW) is a traditional Chinese medicine that is principally used for kidney deficiency, qi stagnation, and blood stasis, which are basic syndromes of infertility in China. KW can improve ovarian follicular development, ovarian function, and endometrial receptivity, which lead to improving pregnancy outcomes. Repeated controlled ovarian hyperstimulation (COH) reduces oocyte quality and results in a lower pregnancy rate. Whether KW has the potential to improve oocyte quality reduced by repeated COH has yet to be determined.

AIMS OF THE STUDY

The aim of this study wwas to evaluate the effect of KW on oocyte quality after damage due to repeated COH, and to investigate the mechanism(s) underlying the antioxidative protection of oocytes by mitochondria.

MATERIALS AND METHODS

Female Kunming mice were randomly divided into four groups: normal group, model (repeated COH) group, KW group, and N-acetylcysteine (NAC) group. We observed the morphology and quality of mitochondria, level of reactive oxygen species (ROS), and antioxidant enzymes activity of each group. Oocytes were treated with H2O2 and KW-containing serum, and we determined the antioxidant effects of KW on H2O2-treated oocytes and the mechanism involved in the regulation of Nrf2 in reducing oxidative damage.

RESULTS

Our results revealed that repeated COH caused oxidative damage and impaired oocyte mitochondrial function and structure, resulting in poor oocyte quality. KW pretreatment reduced oxidative damage by inhibiting ROS production and improving mitochondrial structure and function, thereby enhancing overall oocyte quality. In response to H2O2, KW activated the PKC/Keap1/Nrf2-signaling pathway and promoted the translocation of Nrf2 from the cytoplasm to the nucleus, which activated the expression of SOD and GSH-Px, and removed the excess ROS that caused the initial mitochondrial damage.

CONCLUSIONS

KW improved oocyte quality perturbed by repeated COH via reducing oxidative effects and improving mitochondrial function. The mechanism may be related to regulation of the PKC/Keap1/Nrf2 pathway in removing excess ROS.

CPEB1-dependent disruption of the mRNA translation program in oocytes during maternal aging

The molecular causes of deteriorating oocyte quality during aging are poorly defined. Since oocyte developmental competence relies on post-transcriptional regulations, we tested whether defective mRNA translation contributes to this decline in quality. Disruption in ribosome loading on maternal transcripts is present in old oocytes. Using a candidate approach, we detect altered translation of 3'-UTR-reporters and altered poly(A) length of the endogenous mRNAs. mRNA polyadenylation depends on the cytoplasmic polyadenylation binding protein 1 (CPEB1). Cpeb1 mRNA translation and protein levels are decreased in old oocytes. This decrease causes de-repression of Ccnb1 translation in quiescent oocytes, premature CDK1 activation, and accelerated reentry into meiosis. De-repression of Ccnb1 is corrected by Cpeb1 mRNA injection in old oocytes. Oocyte-specific Cpeb1 haploinsufficiency in young oocytes recapitulates all the translation phenotypes of old oocytes. These findings demonstrate that a dysfunction in the oocyte translation program is associated with the decline in oocyte quality during aging.

Single intraovarian dose of stem cell- and platelet-secreted factors mitigates age-related ovarian infertility in a murine model

BACKGROUND

Systemic administration of soluble factors from bone marrow-derived stem cells combined with activated platelet-rich plasma (SC-PRP) restored ovarian function, mediated through paracrine signaling, in murine models of chemotherapy-induced ovarian damage and human tissue from poor responder patients. However, the effects against age-related infertility and the efficacy of local administration have not been evaluated yet.

OBJECTIVE

This study aimed to assess whether a single intraovarian dose of stem cells combined with activated platelet-rich plasma can recover ovarian function, oocyte quality, and developmental competence in older mice.

STUDY DESIGN

The effects of stem cells combined with activated platelet-rich plasma against age-related infertility were assessed following controlled ovarian stimulation in an aging murine model reproducing 3 physiological stages of women's reproductive life, namely young, advanced maternal age, and menopausal (n=12 animals per group). Female mice were randomized to receive a single intraovarian injection (10 μL/ovary) of either saline, activated platelet-rich plasma, or stem cells combined with activated platelet-rich plasma. Seven days later, the mice were stimulated, naturally mated, and sacrificed to harvest their ovaries for histologic assessment and molecular analysis and their oviducts to evaluate oocyte maturation and to assess early embryo development.

RESULTS

A single intraovarian injection of stem cells combined with activated platelet-rich plasma promoted follicle activation and development in young, advanced maternal age, and old mice. Furthermore, stem cells combined with activated platelet-rich plasma rescued fertility in older mice by enhancing the quantity and quality of ovulated mature oocytes and supporting early embryo development to the blastocyst stage in all the evaluated ages. These fertility outcomes were positively associated with mitochondrial quality, treatment-increased mitochondrial DNA copy numbers, and reduced oxidative damage and apoptosis. Finally, the effects observed by histologic analysis were supported at the proteomic level. Functional proteomic analyses revealed molecular mechanisms involved in oocyte maturation and quality, mitochondrial function, and recovery of the ovarian stroma.

CONCLUSION

Bone marrow-derived stem cells combined with activated platelet-rich plasma is a promising treatment with the potential to improve the reproductive outcomes of women with age-related infertility, exceeding the restorative effects of platelet-rich plasma alone. Although further research in human ovarian samples is still required, the autologous nature of stem cell factors collected by noninvasive mobilization, their combination with platelet-rich plasma, and the local administration route suggest that stem cells combined with activated platelet-rich plasma treatment could be a potentially effective and safe application for future clinical practice.

Fertility intention among married women in Ethiopia: a multilevel analysis of Ethiopian demographic health survey 2016

BACKGROUND

Fertility intention is the central aspect of countries which determine their population demography. Therefore, proportion and factors associated with fertility intention should be studied at different level of community for designing of appropriate policies, strategies, and programs. Despite its importance, information is scarce about proportion and predictors of fertility intention among women of reproductive age in Ethiopia, in 2016.

METHODS

A secondary data analysis was done on 2016 Ethiopian Demographic and Health Survey/EDHS/ in this study. A total of 1423 fecund, married, and sexually active women were included this study. Multilevel mixed-effect logistic regression model was done to show association between fertility desire and explanatory variables. Adjusted Odds Ratio with 95% Confidence Interval (CI) was computed to assess the strength and significance of association.

RESULTS

Prevalence of fertility intention was 63.5% (95%CI:62.2%,64.8%) in Ethiopia, in 2016. The response rate of this study was 100%. The odd of fertility desire was higher among women of age 20-34 years (AOR=2.5,95%CI:1.5,4.0), women of age 35-49 years (AOR= 9,95%CI:12.2,45.4), Muslim followers (AOR=5.4,95%CI:3.6,7.9), other religions followers (AOR= 1.8,95%CI:1.2,3.0), women who did not want to use modern contraceptive (AOR=3.1,95%CI:2.2,4.3). However, the likelihood of fertility intention was low among women who owned mobile phone (AOR=0.6,95%CI:0.4,0.87), and women with more than one partner (AOR=0.5,95%CI:0.41,0.8). At the community level factors like: Community education status (AOR= 1.67,95%CI:1.26,2.2) and region were factors strongly linked to fertility intention.

CONCLUSIONS

In this study, prevalence of fertility desire was higher compared to other countries. Participants age, religion, intention to use modern contraceptive, own mobile, and having multiple partners were individual factors associated with fertility preference. Furthermore, educational status and region were community factor associated significantly with intention of fertility. Hence, expansion of mobile networking and family planning messages through mobile. Furthermore, religious teaching should be enhanced to control family size among followers. Finally, the Ethiopian government should also work strongly to improve community education.

Epigenetic clocks provide clues to the mystery of uterine ageing

BACKGROUND

Rising maternal ages and age-related fertility decline are a global challenge for modern reproductive medicine. Clinicians and researchers pay specific attention to ovarian ageing and hormonal insufficiency in this regard. However, uterine ageing is often left out of the picture, with the majority of reproductive clinicians being close to unanimous on the absence of age-related functional decline in the uterine tissues. Therefore, most existing techniques to treat an age-related decline in implantation rates are based primarily on hormonal supplementation and oocyte donation. Solving the issue of uterine ageing might lead to an adjustment to these methods.

OBJECTIVE AND RATIONALE

A focus on uterine ageing and the possibility of slowing it emerged with the development of the information theory of ageing, which identifies genomic instability and erosion of the epigenetic landscape as important drivers of age-related decline in the functionality of most cells and tissues. Age-related smoothing of this landscape and a decline in tissue function can be assessed by measuring the ticking of epigenetic clocks. Within this review, we explore whether the uterus experiences age-related alterations using this elegant approach. We analyse existing data on epigenetic clocks in the endometrium, highlight approaches to improve the accuracy of the clocks in this cycling tissue, speculate on the endometrial pathologies whose progression might be predicted by the altered speed of epigenetic clocks and discuss the possibilities of slowing down the ticking of these clocks.

SEARCH METHODS

Data for this review were identified by searches of Medline, PubMed and Google Scholar. References from relevant articles using the search terms 'ageing', 'maternal age', 'female reproduction', 'uterus', 'endometrium', 'implantation', 'decidualization', 'epigenetic clock', 'biological age', 'DNA methylation', 'fertility' and 'infertility' were selected. A total of 95 articles published in English between 1985 and 2022 were included, six of which describe the use of the epigenetic clock to evaluate uterine/endometrium ageing.

OUTCOMES

Application of the Horvath and DNAm PhenoAge epigenetic clocks demonstrated a poor correlation with chronological age in the endometrium. Several approaches were suggested to enhance the predictive power of epigenetic clocks for the endometrium. The first was to increase the number of samples in the training dataset, as for the Zang clock, or to use more sophisticated clock-building algorithms, as for the AltumAge clock. The second method is to adjust the clocks according to the dynamic nature of the endometrium. Using either approach revealed a strong correlation with chronological age in the endometrium, providing solid evidence for age-related functional decline in this tissue. Furthermore, age acceleration/deceleration, as estimated by epigenetic clocks, might be a promising tool to predict or to gain insights into the origin of various endometrial pathologies, including recurrent implantation failure, cancer and endometriosis. Finally, there are several strategies to slow down or even reverse epigenetic clocks that might be applied to reduce the risk of age-related uterine impairments.

WIDER IMPLICATIONS

The uterine factor should be considered, along with ovarian issues, to correct for the decline in female fertility with age. Epigenetic clocks can be tested to gain a deeper understanding of various endometrial disorders.

Role of N-acetylcysteine treatment in women with advanced age undergoing IVF/ICSI cycles: A prospective study

Objective

The main objective of this study was to explore the efficacy of a new antioxidant N-acetylcysteine (NAC) supplementation in reproductive outcomes of advanced age women undergoing in vitro fertilization/intracytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET), and the effect on the expression of L-glutathione (GSH) in follicular fluid (FF) and mitochondrial DNA (mtDNA) copy number of granulosa cells.

Methods

The present prospective randomized controlled study was conducted in 200 patients with advanced age women undergoing GnRH antagonist protocol. The treatment group (group A) consisted of 100 women who received N-acetylcysteine treatment from the menstrual phase of the previous cycle for about 45 days using the GnRH antagonist protocol. The control group (group B) consisted of 100 women who received the same protocol without N-acetylcysteine. Total gonadotrophin dosage the number of oocyte received, high-quality blastocysts, and pregnancy outcomes were compared between two groups. Pregnancy outcomes included biochemical pregnancy rate, clinical pregnancy rate, embryo implantation rate, ectopic pregnancy rate, multiple pregnancy rate, and ongoing pregnancy rate. Follicular fluid (FF) was collected after oocytes were gathered. The GSH content in the FF was tested with enzyme linked immunosorbent assay (ELISA). The mtDNA copy number of the granulosa cells was measured using real-time PCR techniques.

Results

Total doses of Gn in the NAC treatment group were less than those in the control group (2385.50 ± 879.19 vs. 2527.63 ± 1170.33, P = 0.047). Compared with the control, the number of high-quality blastocysts in NAC treatment increased significantly (1.82 ± 2.12 vs. 1.43 ± 1.58, p = 0.014). Clinical pregnancy rates did not differ in both groups (all P > 0.05). At the same time, the GSH content in the FF differed significantly between the two groups (1.88 ± 1.23 vs. 1.07 ± 0.70, p = 0.001). There was no significant difference in the mtDNA copy number between the two groups (P = 0.157).

Conclusion

A combination of NAC and Gn treatment is capable of improving the ovarian response to superovulation drugs in assisted reproductive technologies (ARTs) and also in aged populations. The addition of NAC during IVF can improve the quality of blastocysts in advanced age female subjects. However, more clinical trials are required to be designed to confirm this conclusion in future.

Ethics and dissemination

The experiment solicited approval from the Institutional ethics committee of the Affiliated Reproductive Hospital of Shandong University. All the participants provided written informed consent. This survey was conducted as per the Declaration of Helsinki and relevant amendments.

Trial registration number

www.chictr.org.cn, identifier ChiCTR2100048297.

Activated protein C resistance impact on Syrian candidates for in vitro fertilisation and the benefit of anticoagulation therapy: a retrospective cohort study

Activated protein C resistance (APCR) is a common thrombophilia, caused mainly by a mutation. The impact of APCR on the efficacy of In Vitro Fertilization (IVF) are still unclear, and no solid recommendations for its management were published. To investigate the effect of APCR on IVF outcomes and assess the efficacy of our management protocol, we retrospectively scanned the medical records of women who were tested with APCR assay in 2019 at our fertility centre. The 66 women (12%) positive for APCR had lower odds of reaching clinical pregnancies after IVF 0.18 [95% CI: 0.07-0.47] and fewer live births. The administration of low-molecular-weight heparin and aspirin associated with more implantation in treated compared to untreated APCR-positive women with an odds ratio of 43.2 [7.51-248.6]. In conclusion, APCR negatively affects the number of clinical pregnancies after IVF, but anticoagulation therapy can mitigate this effect and significantly increase clinical pregnancies.Impact StatementWhat is already known on this subject? The evidence about the impact of APCR on IVF outcomes is still inconclusive. According to the Canadian guideline, routine screening for thrombophilia in patients with recurrent pregnancy loss is not recommended. No clear recommendations regarding the management of APCR in the planning for IVF are yet available.What do the results of this study add? APCR significantly increases implantation failure among infertile women who conduct IVF. Management of APCR using LMWH and aspirin was effective in mitigating this effect and increasing successful implantation.What are the implications of these findings for clinical practice and/or further research? Our findings can support the recommendation to include APCR assay in the routine tests for infertile women conducting IVF, and suggest the combination between LMWH and aspirin as an effective therapy to increase successful implantation in APCR positive candidates. However, more controlled clinical trials are still needed to confirm our results.

Predicting IVF outcome in poor ovarian responders

Background

Poor responders to ovarian stimulation are one of the most challenging populations to treat. As a failed cycle can cause a considerable emotional and economical loss, adequate fertility counseling addressing patients’ expectations are highly important when facing patients with poor ovarian response. The study aimed to evaluate reproductive outcomes and to identify factors associated with live birth (LB) after fresh autologous IVF/intracytoplasmic sperm injection (ICSI) cycles of patients fulfilling the Bologna criteria for poor ovarian response (POR).

Methods

A retrospective study included 751 IVF/ICSI treatment cycles which yielded up to three retrieved oocytes, at a tertiary referral hospital between January 2016 and February 2020. A logistic regression analysis was used to adjust for confounders.

Results

Clinical pregnancy and LB rate per cycle were significantly higher among women younger versus older than 40 years (9.8% and 6.8% vs 4.5% and 2.1%, p < 0.01, respectively). Patients who achieved LB were significantly younger, had higher number of oocytes retrieved, fertilization rate and top-quality embryos (p < 0.05). Multivariable regression analysis identified patient’s age (OR 0.90; 95% CI 0.845–0.97; p = 0.005) and mean number retrieved oocytes (OR 1.95; 95% CI 1.20–3.16; p = 0.007) as factors significantly associated with the probability of a LB.

Conclusions

The woman’s age and the number of retrieved oocytes are both independent predicting factors of live birth in poor ovarian responders. Considering the risks, the high financial investment and poor reproductive outcomes involved in IVF treatments, raises questions regarding the adequacy of providing treatments in these patients' population. POR younger than 40 years may represent a possible exception due to acceptable probability for a LB.

Circular RNA expression profiles of ovarian granulosa cells in advanced-age women explain new mechanisms of ovarian aging

Aim: We aimed to determine the role of granulosa cells (GCs) circular RNA (circRNA) in ovarian aging. Methods: Nine women were recruited, including three diminished ovarian reserve young women, three advanced-aged women and three normal ovarian reserve young women. The circRNA expression profiles of GCs were characterized by CLEAR software. Key circRNA were validated by quantitative reverse transcription PCR. Results: GCs in advanced-age group females exhibited active MHC class II-related biological processes. A total of 3575 circRNAs were found in the advanced age group. Hsa-circ-0031584 appears to be one of the important molecules regulating the mitotic process of GCs. Conclusion: The expression profiles of circRNAs exhibited obvious stage specificity with age which might contribute to ovarian aging progression.

Effects of putrescine on the quality and epigenetic modification of mouse oocytes during in vitro maturation

CONTEXT

Low ovarian putrescine levels and decreased peak values following luteinising hormone peaks are related to poor oocyte quantity and quality in ageing women.

AIMS

To investigate the effects of putrescine supplementation in in vitro maturation (IVM) medium on oocyte quality and epigenetic modification.

METHODS

Germinal vesicle oocytes retrieved from the ovaries of 8-week-old and 9-month-old mice were divided into four groups (the young, young+difluoromethylornithine (DFMO), ageing and ageing+putrescine groups) and cultured in IVM medium with or without 1mM putrescine or DFMO for 16h. The first polar body extrusion (PBE), cleavage and embryonic development were evaluated. Spindles, chromosomes, mitochondria and reactive oxygen species (ROS) were measured. The expression levels of SIRT1, H3K9ac, H3K9me2, H3K9me3, and 5mC levels were evaluated. Sirt1 and imprinted genes were detected.

RESULTS

The PBE was higher in the ageing+putrescine group than in the ageing group. Putrescine increased the total and inner cell mass cell numbers of blastocysts in ageing oocytes. Putrescine decreased aberrant spindles and chromosome aneuploidy, increased the mitochondrial membrane potential and decreased ROS levels. Putrescine increased SIRT1 expression and attenuated the upregulation of H3K9ac levels in ageing oocytes. Putrescine did not affect 5mC, H3K9me2 or H3K9me3 levels or imprinted gene expression.

CONCLUSIONS

Putrescine supplementation during IVM improved the maturation and quality of ageing oocytes and promoted embryonic development by decreasing ROS generation, maintaining mitochondrial and spindle function and correcting aberrant epigenetic modification.

IMPLICATIONS

Putrescine shows application potential for human-assisted reproduction, especially for IVM of oocytes from ageing women.

Contraception During Perimenopause: Practical Guidance

Climacteric is by no means in itself a contraindication to safe contraception. On the contrary, there are several conditions related to the perimenopause that could benefit from the use of modern contraceptives, mainly hormonal, with the goals of avoiding unintended pregnancies and giving further possible benefits beyond contraception (menstrual cycle control, a reduction of vasomotor symptoms and menstrual migraines, a protection against bone loss, a positive oncological risk/benefit balance). This narrative review aims to provide practical guidance on their possible use in this particular life stage, both short- and long-acting reversible contraceptives, and to assist clinicians for women transitioning from contraception to their menopausal years, including the possible initiation of postmenopausal hormone therapy. Comprehensive contraceptive counselling is an essential aspect of the overall health and wellbeing of women and should be addressed with each such patient irrespective of age.

Whole ovary laparoscopic incisions improve hormonal response and fertility in extremely poor ovarian response patients

STUDY OBJECTIVE

Recent findings have shown mechanical fragmentation of ovarian cortex and ovarian drilling could promote follicle growth in patients with premature ovarian insufficiency (POI) and polycystic ovarian syndrome, respectively. A common element shared by these treatments is the mechanical disturbance of ovarian extracellular matrix (ECM) tissues. We thus hypothesized a simplified whole ovary laparoscopic incision (WOLI) procedure may provide the intrinsic stimuli needed to activate resting follicles in extremely poor ovarian response (EPOR) patients who had negligible chance of becoming pregnant with their own oocytes via modern IVF practice.

DESIGN

Retrospective pilot study SETTING: The study was conducted in a research medical center in Taiwan.

PATIENTS

Women who had multiple canceled ovarian stimulation cycles due to the lack of follicle growth were recruited. A total of 6 EPOR patients received the WOLI procedure, which covers the whole surface of ovaries, in 2015-2017.

INTERVENTIONS

After receiving an outpatient WOLI procedure, ovarian response and follicle growth were monitored for 90 days with or without gonadotropin stimulation. Embryo quality and clinical outcomes were analyzed.

MEASUREMENTS AND MAIN RESULTS

Following the WOLI treatment, 5 out of 6 patients had significant increases in serum estradiol level and improved follicle growth (p = 0.000537). Multiple oocytes were retrieved from each of these patients, and it led to thawed embryo transfer cycles in four patients (p = 0.010). On average, the duration from the WOLI procedure to the first ovum pickup was 24 days (11-58 days). Following embryo transfer, two patients became pregnant and delivered healthy babies. Two other patients received embryo transfer, and one led to a chemical pregnancy. One patient had cryopreserved embryos with pending transfer.

CONCLUSION

The standardizable WOLI procedure restored hormonal responses in a majority of EPOR patients. Further validation of this novel and yet simple laparoscopic procedure, which requires only one laparoscopic surgery, may provide a practical option to reactivate the aging ovarian environment in EPOR and POI patients.

Mitochondrial supplementation of Sus scrofa metaphase II oocytes alters DNA methylation and gene expression profiles of blastocysts

Background

Mitochondrial DNA (mtDNA) copy number in oocytes correlates with oocyte quality and fertilisation outcome. The introduction of additional copies of mtDNA through mitochondrial supplementation of mtDNA-deficient Sus scrofa oocytes resulted in: (1) improved rates of fertilisation; (2) increased mtDNA copy number in the 2-cell stage embryo; and (3) improved development of the embryo to the blastocyst stage. Furthermore, a subset of genes showed changes in gene expression. However, it is still unknown if mitochondrial supplementation alters global and local DNA methylation patterns during early development.

Results

We generated a series of embryos in a model animal, Sus scrofa, by intracytoplasmic sperm injection (ICSI) and mitochondrial supplementation in combination with ICSI (mICSI). The DNA methylation status of ICSI- and mICSI-derived blastocysts was analysed by whole genome bisulfite sequencing. At a global level, the additional copies of mtDNA did not affect nuclear DNA methylation profiles of blastocysts, though over 2000 local genomic regions exhibited differential levels of DNA methylation. In terms of the imprinted genes, DNA methylation patterns were conserved in putative imprint control regions; and the gene expression profile of these genes and genes involved in embryonic genome activation were not affected by mitochondrial supplementation. However, 52 genes showed significant differences in expression as demonstrated by RNAseq analysis. The affected gene networks involved haematological system development and function, tissue morphology and cell cycle. Furthermore, seven mtDNA-encoded t-RNAs were downregulated in mICSI-derived blastocysts suggesting that extra copies of mtDNA affected tRNA processing and/or turnover, hence protein synthesis in blastocysts. We also showed a potential association between differentially methylated regions and changes in expression for 55 genes due to mitochondrial supplementation.

Conclusions

The addition of just an extra ~ 800 copies of mtDNA into oocytes can have a significant impact on both gene expression and DNA methylation profiles in Sus scrofa blastocysts by altering the epigenetic programming established during oogenesis. Some of these changes may affect specific tissue-types later in life. Consequently, it is important to determine the longitudinal effect of these molecular changes on growth and development before considering human clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13072-022-00442-x.

Effect of rLH Supplementation during Controlled Ovarian Stimulation for IVF: Evidence from a Retrospective Analysis of 1470 Poor/Suboptimal/Normal Responders Receiving Either rFSH plus rLH or rFSH Alone

We retrospectively studied a real-life population of 1470 women undergoing IVF, with poor/suboptimal/normal ovarian responsiveness to controlled ovarian stimulation (COS), comparing the cumulative live birth rate (cLBR) when COS was performed using rFSH alone or rFSH + rLH in a 2:1 ratio. Overall, we observed significantly higher cLBR in the rFSH alone group than in the rFSH + rLH group (29.3% vs. 22.2%, p < 0.01). However, considering only suboptimal/poor responders (n = 309), we observed comparable cLBR (15.6% vs. 15.2%, p = 0.95) despite the fact that patients receiving rFSH + rLH had significantly higher ages and worse ovarian reserve markers. The equivalent effectiveness of rFSH + rLH and rFSH alone was further confirmed after stratification according to the number of oocytes retrieved: despite basal characteristics were still in favor of rFSH alone group, the cLBR always resulted comparable. Even subdividing patients according to the POSEIDON classification, irrespective of differences in the baseline clinical characteristics in favor of FSH alone group, the cLBR resulted comparable in all subgroups. Despite the retrospective, real-life analysis, our data suggest that rLH supplementation in COS may represent a reasonable option for patients with predictable or unexpected poor/suboptimal ovarian responsiveness to FSH, those matching the Bologna criteria for poor responsiveness, and those included in the POSEIDON classification.

Chromosome Segregation in the Oocyte: What Goes Wrong during Aging

Human female fertility and reproductive lifespan decrease significantly with age, resulting in an extended post-reproductive period. The central dogma in human female reproduction contains two important aspects. One is the pool of oocytes in the human ovary (the ovarian reserve; approximately 10⁶ at birth), which diminishes throughout life until menopause around the age of 50 (approximately 10³ oocytes) in women. The second is the quality of oocytes, including the correctness of meiotic divisions, among other factors. Notably, the increased rate of sub- and infertility, aneuploidy, miscarriages, and birth defects are associated with advanced maternal age, especially in women above 35 years of age. This postponement is also relevant for human evolution; decades ago, the female aging-related fertility drop was not as important as it is today because women were having their children at a younger age. Spindle assembly is crucial for chromosome segregation during each cell division and oocyte maturation, making it an important event for euploidy. Consequently, aberrations in this segregation process, especially during the first meiotic division in human eggs, can lead to implantation failure or spontaneous abortion. Today, human reproductive medicine is also facing a high prevalence of aneuploidy, even in young females. However, the shift in the reproductive phase of humans and the strong increase in errors make the problem much more dramatic at later stages of the female reproductive phase. Aneuploidy in human eggs could be the result of the non-disjunction of entire chromosomes or sister chromatids during oocyte meiosis, but partial or segmental aneuploidies are also relevant. In this review, we intend to describe the relevance of the spindle apparatus during oocyte maturation for proper chromosome segregation in the context of maternal aging and the female reproductive lifespan.

The making of 'old eggs': the science of reproductive ageing between fertility and anti-ageing technologies

This article proposes going back in the history of reproductive medicine to shed light on the role of assisted reproductive technology (ART) in the making of 'old eggs'. Focusing on two key technologies - egg donation and cytoplasmic transfer - both of which contributed significantly to the production of scientific knowledge about reproductive ageing, the article suggests that ART can be analysed as 'in-vivo models' playing a pivotal role in the shift from age as a demographic variable to ageing understood in biological terms. It will shed light on the role of ART in locating age in the eggs and producing a cellular understanding of fertility decline. It argues that ART not only offers new means of reconfiguring the biological clock by extending fertility, but also reconfigures the biology of reproductive ageing itself. This becomes both the target and the means for new technological interventions, imaginaries and norms, anchored in women's bodies and a more plastic biology, and thereby illuminates hitherto underexplored aspects of the encounter between the science and technology of reproduction and anti-ageing.

The mitochondrial protease LONP1 maintains oocyte development and survival by suppressing nuclear translocation of AIFM1 in mammals

Background

Oogenesis is a fundamental process of human reproduction, and mitochondria play crucial roles in oocyte competence. Mitochondrial ATP-dependent Lon protease 1 (LONP1) functions as a critical protein in maintaining mitochondrial and cellular homeostasis in somatic cells. However, the essential role of LONP1 in maintaining mammalian oogenesis is far from elucidated.

Methods

Using conditional oocyte Lonp1-knockout mice, RNA sequencing (RNA-seq) and coimmunoprecipitation/liquid chromatography–mass spectrometry (Co-IP/LC–MS) technology, we analysed the functions of LONP1 in mammalian oogenesis.

Findings

Conditional knockout of Lonp1 in mouse oocytes in both the primordial and growing follicle stages impairs follicular development and causes progressive oocyte death, ovarian reserve loss, and infertility. LONP1 directly interacts with apoptosis inducing factor mitochondria-associated 1 (AIFM1), and LONP1 ablation leads to the translocation of AIFM1 from the cytoplasm to the nucleus, causing apoptosis in mouse oocytes. In addition, women with pathogenic variants of LONP1 lack large antral follicles (>10 mm) in the ovaries, are infertile and present premature ovarian insufficiency.

Interpretation

We demonstrated the function of LONP1 in regulating oocyte development and survival, and in-depth analysis of LONP1 will be crucial for elucidating the mechanisms underlying premature ovarian insufficiency.

Funding

This work was supported by grants from the National Key Research and Development Program of China (2018YFC1004701), the National Nature Science Foundation of China (82001629, 81871128, 81571391, 81401166, 82030040), the Jiangsu Province Social Development Project (BE2018602), the Jiangsu Provincial Medical Youth Talent (QNRC2016006), the Youth Program of the Natural Science Foundation of Jiangsu Province (BK20200116) and Jiangsu Province Postdoctoral Research Funding (2021K277B).

SESN2/NRF2 signaling activates as a direct downstream regulator of the PERK pathway against endoplasmic reticulum stress to improve the in vitro maturation of porcine oocytes

Nuclear erythroid 2-related factor 2 (NRF2) is a critical regulator of oxidative stress in mammalian oocytes. Our previous study described the protective effects of Sestrin-2 (SESN2) as a stress regulator against endoplasmic reticulum (ER) stress in porcine oocytes during in vitro maturation (IVM). However, their roles in unfolded protein response-related signaling pathways in porcine oocyte maturation capacity remain unknown. The purpose of this study was to evaluate the role of SESN2/NRF2 signaling in H₂O₂-induced oxidative stress and ER stress via protein kinase-like ER kinase (PERK) downstream factor during porcine oocyte maturation. Here, we found that the p-NRF2(Ser40) activation in the nucleus of porcine oocytes was accompanied by PERK signaling downregulation using western blot and immunofluorescence staining at 44 h after IVM. The total and nuclear NRF2 protein expression was also induced in porcine oocytes following H₂O₂ and tunicamycin (Tm) exposure. Notably, the upregulation of PERK signaling significantly increased the SESN2 and NRF2 signaling in H₂O₂-and Tm-exposed porcine cumulus oocyte complexes. Interestingly, inducing the knockdown of the SESN2 gene expression by siRNA interrupted the NRF2 signaling activation of porcine oocyte maturation, whereas NRF2 expression blockade by ochratoxin A, an NRF2 inhibitor, did not affect the expression level of the SESN2 protein. Moreover, a defect in SESN2 completely blocked the activity of nuclear NRF2 on spindle assembly in porcine oocytes. These findings suggest that the PERK/SESN2/NRF2 signaling pathway may play an important role against ER stress during meiotic maturation and oocyte maturation capacity.

Factors Influencing the In Vitro Maturation (IVM) of Human Oocyte

In vitro maturation (IVM) of oocytes is a promising assisted reproductive technology (ART) deemed as a simple and safe procedure. It is mainly used in patients with impaired oocyte maturation and in fertility preservation for women facing the risk of losing fertility. However, to date, it is still not widely used in clinical practice because of its underperformance. The influencing factors, such as biphasic IVM system, culture medium, and the supplementation, have a marked effect on the outcomes of oocyte IVM. However, the role of different culture media, supplements, and follicular priming regimens in oocyte IVM have yet to be fully clarified and deserve further investigation.

Large-scale DNA demethylation occurs in proliferating ovarian granulosa cells during mouse follicular development

During ovarian follicular development, granulosa cells proliferate and progressively differentiate to support oocyte maturation and ovulation. To determine the underlying links between proliferation and differentiation in granulosa cells, we determined changes in 1) the expression of genes regulating DNA methylation and 2) DNA methylation patterns, histone acetylation levels and genomic DNA structure. In response to equine chorionic gonadotropin (eCG), granulosa cell proliferation increased, DNA methyltransferase (DNMT1) significantly decreased and Tet methylcytosine dioxygenase 2 (TET2) significantly increased in S-phase granulosa cells. Comprehensive MeDIP-seq analyses documented that eCG treatment decreased methylation of promoter regions in approximately 40% of the genes in granulosa cells. The expression of specific demethylated genes was significantly increased in association with specific histone modifications and changes in DNA structure. These epigenetic processes were suppressed by a cell cycle inhibitor. Based on these results, we propose that the timing of sequential epigenetic events is essential for progressive, stepwise changes in granulosa cell differentiation.

The Mechanism of Traditional Chinese Medicine Based on Semi-Targeted Metabolomics to Improve IVF Outcomes in Senile Patients

Objective

To identify the biological function and metabolic pathway of differential metabolites in follicular fluid of senile patients with kidney qi deficiency undergoing in vitro fertilization-embryo transfer (IVF-ET) and observe the effect of kidney-invigorating herbs on IVF outcomes in senile patients.

Methods

A total of 95 women undergoing IVF treatment were recruited and divided into three groups, including 34 cases in the treatment group (the senile patients with kidney qi deficiency after the intervention of Chinese medicine), 31 cases in the experiment group (the senile patients with kidney qi deficiency of no intervention of Chinese medicine), and 30 cases in the control group (young women with infertility due to male factor). The three groups of women were treated with long protocol ovarian hyperstimulation; the treatment group was given Qi-Zi-Yu-Si decoction on the day of HCG downregulation. Their IVF clinical outcomes were observed. The metabolites changes of kidney qi deficiency syndrome were analyzed in follicular fluid metabolomics using liquid chromatography-mass spectrometry (UPLC-MS/MS).

Results

The syndrome score of kidney qi deficiency syndrome in the treatment group was significantly improved after treatment (P < 0.01). Compared with the experiment group, the available embryo rate and implantation rate were increased, and the difference was statistically significant (P < 0.05). Progesterone, indoleacrylic acid, 2-propenyl 1-(1-propenylsulfinyl) propyl disulfide, N-acetyltryptophan, decanoylcarnitine, 20a-dihydroprogesterone, testosterone acetate, eicosatrienoic acid, 1H-indole-3-carboxaldehyde, choline, phosphorylcholine, and tryptophan were downregulated in the treatment group. Through pathway analysis, glycerophospholipid metabolism and steroid hormone biosynthesis were regulated in senile patients with kidney qi deficiency after Qi-Zi-Yu-Si decoction intervention.

Conclusion

Qi-Zi-Yu-Si decoction can effectively improve the IVF outcome and clinical symptoms of senile patients. Follicular fluid metabolites were significantly changed in senile infertile women with kidney qi deficiency, and the mechanism by which kidney-invigorating herbs improve IVF treatment outcomes may be related to glycerophospholipid metabolism and steroid hormone biosynthesis. This study was registered in the Chinese Clinical Trials Registry Platform (ChiCTR1800014422).

The impact of maternal age on gene expression during the GV to MII transition in euploid human oocytes

STUDY QUESTION

Are there age-related differences in gene expression during the germinal vesicle (GV) to metaphase II (MII) stage transition in euploid human oocytes?

SUMMARY ANSWER

A decrease in mitochondrial-related transcripts from GV to MII oocytes was observed, with a much greater reduction in MII oocytes with advanced age.

WHAT IS KNOWN ALREADY

Early embryonic development is dependent on maternal transcripts accumulated and stored within the oocyte during oogenesis. Transcriptional activity of the oocyte, which dictates its ultimate developmental potential, may be influenced by age and explain the reduced competence of advanced maternal age (AMA) oocytes compared with the young maternal age (YMA). Gene expression has been studied in human and animal oocytes; however, RNA sequencing could provide further insights into the transcriptome profiling of GV and in vivo matured MII euploid oocytes of YMA and AMA patients.

STUDY DESIGN, SIZE, DURATION

Fifteen women treated for infertility in a single IVF unit agreed to participate in this study. Five GV and 5 MII oocytes from 6, 21-26 years old women (YMA cohort) and 5 GV and 6 MII oocytes from 6, 41-44 years old women (AMA cohort) undergoing IVF treatment were donated. The samples were collected within a time frame of 4 months. RNA was isolated and deep sequenced at the single-cell level. All donors provided either GV or MII oocytes.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Cumulus dissection from donated oocytes was performed 38 h after hCG injection, denuded oocytes were inserted into lysis buffer supplemented with RNase inhibitor. The samples were stored at -80°C until further use. Isolated RNA from GV and MII oocytes underwent library preparation using an oligo deoxy-thymidine (dT) priming approach (SMART-Seq v4 Ultra Low Input RNA assay; Takara Bio, Japan) and Nextera XT DNA library preparation assay (Illumina, USA) followed by deep sequencing. Data processing, quality assessment and bioinformatics analysis were performed using source-software, mainly including FastQC, HISAT2, StringTie and edgeR, along with functional annotation analysis, while scploid R package was employed to determine the ploidy status.

MAIN RESULTS AND THE ROLE OF CHANCE

Following deep sequencing of single GV and MII oocytes in both YMA and AMA cohorts, several hundred transcripts were found to be expressed at significantly different levels. When YMA and AMA MII oocyte transcriptomes were compared, the most significant of these were related to mitochondrial structure and function, including biological processes, mitochondrial respiratory chain complex I assembly and mitochondrial translational termination (false discovery rate (FDR) 6.0E-10 to 1.2E-7). These results indicate a higher energy potential of the YMA MII cohort that is reduced with ageing. Other biological processes that were significantly higher in the YMA MII cohort included transcripts involved in the translation process (FDR 1.9E-2). Lack of these transcripts could lead to inappropriate protein synthesis prior to or upon fertilisation of the AMA MII oocytes.

LARGE SCALE DATA

The RNA sequencing data were deposited in the Gene Expression Omnibus (https://www.ncbi.nlm.nih.gov/geo), under the accession number: GSE164371.

LIMITATIONS, REASONS FOR CAUTION

The relatively small sample size could be a reason for caution. However, the RNA sequencing results showed homogeneous clustering with low intra-group variation and five to six biological replicates derived from at least three different women per group minimised the potential impact of the sample size.

WIDER IMPLICATIONS OF THE FINDINGS

Understanding the effects of ageing on the oocyte transcriptome could highlight the mechanisms involved in GV to MII transition and identify biomarkers that characterise good MII oocyte quality. This knowledge has the potential to guide IVF regimes for AMA patients.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Medical Research Council (MRC Grant number MR/K020501/1).

Obstetric and neonatal outcomes of pregnancies resulting from preimplantation genetic testing: a systematic review and meta-analysis

BACKGROUND

Preimplantation genetic testing (PGT) includes methods that allow embryos to be tested for severe inherited diseases or chromosomal abnormalities. In addition to IVF/ICSI and repeated freezing and thawing of the embryos, PGT requires a biopsy to obtain embryonic genetic material for analysis. However, the potential effects of PGT on obstetric and neonatal outcomes are currently uncertain.

OBJECTIVE AND RATIONALE

This study aimed to investigate whether pregnancies conceived after PGT were associated with a higher risk of adverse obstetric and neonatal outcomes compared with spontaneously conceived (SC) pregnancies or pregnancies conceived after IVF/ICSI.

SEARCH METHODS

PubMed, EMBASE, MEDLINE, Web of Science and The Cochrane Library entries from January 1990 to January 2021 were searched. The primary outcomes in this study were low birth weight (LBW) and congenital malformations (CMs), and the secondary outcomes included gestational age, preterm delivery (PTD), very preterm delivery (VPTD), birth weight (BW), very low birth weight (VLBW), neonatal intensive care unit (NICU) admission, hypertensive disorders of pregnancy (HDP), gestational diabetes, placenta previa and preterm premature rupture of membranes (PROM). We further pooled the results of PGT singleton pregnancies. Subgroup analyses included preimplantation genetic diagnosis (PGD), preimplantation genetic screening (PGS), cleavage-stage biopsy combined with fresh embryo transfer (CB-ET) and blastocyst biopsy combined with frozen-thawed embryo transfer (BB-FET).

OUTCOMES

This meta-analysis included 15 studies involving 3682 babies born from PGT pregnancies, 127 719 babies born from IVF/ICSI pregnancies and 915 222 babies born from SC pregnancies. The relative risk (RR) of LBW was higher in PGT pregnancies compared with SC pregnancies (RR = 3.95, 95% confidence interval [CI]: 2.32-6.72), but the risk of CMs was not different between the two groups. The pooled results for the risks of LBW and CMs were similar in PGT and IVF/ICSI pregnancies. The risks of PTD (RR = 3.12, 95% CI: 2.67-3.64) and HDP (RR = 3.12, 95% CI: 2.18-4.47) were significantly higher in PGT pregnancies compared with SC pregnancies. Lower gestational age (mean difference [MD] = -0.76 weeks, 95% CI -1.17 to -0.34) and BW (MD = -163.80 g, 95% CI: -299.35 to -28.24) were also noted for PGT pregnancies compared with SC pregnancies. Nevertheless, compared with IVF/ICSI pregnancies, the risks of VPTD and VLBW in PGT pregnancies were significantly decreased by 41% and 30%, respectively, although the risk of HDP was still significantly increased by 50% in PGT pregnancies compared with IVF/ICSI pregnancies. The combined results of obstetric and neonatal outcomes of PGT and IVF/ICSI singleton pregnancies were consistent with the overall results. Further subgroup analyses indicated that both PGD and PGS pregnancies were associated with a higher risk of PTD and a lower gestational age compared with SC pregnancies.

WIDER IMPLICATIONS

This meta-analysis showed that PGT pregnancies may be associated with increased risks of LBW, PTD and HDP compared with SC pregnancies. The overall obstetric and neonatal outcomes of PGT pregnancies are favourable compared with those of IVF/ICSI pregnancies, although PGT pregnancies were associated with a higher risk of HDP. However, because the number of studies that could be included was limited, more randomised controlled trials and prospective cohort studies are needed to confirm these conclusions.

Reproductive senescence impairs the energy metabolism of human luteinized granulosa cells

RESEARCH QUESTION

Female age is the single greatest factor influencing reproductive performance and granulosa cells are considered as potential biomarkers of oocyte quality. Is there an age effect on the energy metabolism of human mural granulosa cells?

DESIGN

Observational prospective cohort and experimental study including 127 women who had undergone IVF cycles. Women were allocated to two groups: a group of infertile patients aged over 38 years and a control group comprising oocyte donors aged less than 35 years. Individuals with pathologies that could impair fertility were excluded from both groups. Following oocyte retrieval, cumulus and granulosa cells were isolated and their bioenergetic properties (oxidative phosphorylation parameters, rate of aerobic glycolysis and adenine nucleotide concentrations) were analysed and compared.

RESULTS

Human mural luteinized granulosa and cumulus cells present high rates of aerobic glycolysis that cannot be increased further when mitochondrial ATP synthesis is inhibited. Addition of follicular fluid to the experimental media is necessary to reach the full respiratory capacity of the cells. Granulosa cells from aged women present lower mitochondrial respiration (12.8 ± 1.6 versus 11.2 ± 1.6 pmol O₂/min/mg; P = 0.046), although mitochondrial mass is not decreased, and lower aerobic glycolysis, than those from young donors (12.9 ± 1.3 versus 10.9 ± 0.5 mpH/min/mg; P = 0.009). The concurrent decrease in the two energy supply pathways leads to a decrease in the cellular energy charge (0.87 ± 0.01 versus 0.83 ± 0.02; P < 0.001).

CONCLUSIONS

Human mural luteinized granulosa cells exhibit a reduction in their energy metabolism as women age that is likely to influence female reproductive potential.

Integrative proteome analysis implicates aberrant RNA splicing in impaired developmental potential of aged mouse oocytes

Aging has many effects on the female reproductive system, among which decreased oocyte quality and impaired embryo developmental potential are the most important factors affecting female fertility. However, the mechanisms underlying oocyte aging are not yet fully understood. Here, we selected normal reproductively aging female mice and constructed a protein expression profile of metaphase II (MII) oocytes from three age groups. A total of 187 differentially expressed (DE) proteins were identified, and bioinformatics analyses showed that these DE proteins were highly enriched in RNA splicing. Next, RNA‐seq was performed on 2‐cell embryos from these three age groups, and splicing analysis showed that a large number of splicing events and genes were discovered at this stage. Differentially spliced genes (DSGs) in the two reproductively aging groups versus the younger group were enriched in biological processes related to DNA damage repair/response. Binding motif analysis suggested that PUF60 might be one of the core splicing factors causing a decline in DNA repair capacity in the subsequent development of oocytes from reproductively aging mice, and changing the splicing pattern of its potential downstream DSG Cdk9 could partially mimic phenotypes in the reproductively aging groups. Taken together, our study suggested that the abnormal expression of splicing regulation proteins in aged MII oocytes would affect the splicing of nascent RNA after zygotic genome activation in 2‐cell embryos, leading to the production of abnormally spliced transcripts of some key genes associated with DNA damage repair/response, thus affecting the developmental potential of aged oocytes.

Erzhi Tiangui Granules Improve In Vitro Fertilization Outcomes in Infertile Women with Advanced Age

Background

The fertility of females with advanced age declines with aging. Therefore, for medical and social reasons, it is important to establish mechanisms to protect and improve the fertility of such populations. With widespread use of traditional Chinese medicine (TCM) in in vitro fertilization (IVF), studies have evaluated their impact on improving the fertility of females with advanced age. In this study, we performed proteomic analysis of follicular fluid to reveal mechanisms of the Erzhi Tiangui (EZTG) granule (Chinese herbs for replenishing vital essence to tonify the kidney) in improving the outcomes of IVF in infertile women with advanced age.

Methods

This was a randomized, double-blind, and placebo-controlled trial in which 100 patients with advanced age were divided into the EZTG group and the placebo group by the random number table plus envelope method. Both groups were subjected to controlled ovarian stimulation with a GnRH antagonist regimen. Differences between the two groups were evaluated, including the TCM syndrome score after treatment, gonadotrophin (Gn) days and Gn doses, the number of retrieved oocytes, 2 pronucleus (PN) fertilization, 2PN cleavage, and high-quality embryos. Differentially expressed proteins were identified using the LC-MS/MS method, and their functions were determined through bioinformatics analyses.

Results

The number of high-quality embryos in the placebo group was significantly lower than that in the EZTG group (2.88 ± 1.85 vs. 4.13 ± 2.83, p=0.011). Eleven differentially expressed proteins were identified between the two groups. Four proteins were highly expressed, whereas seven were suppressed in the control group, compared to the EZTG group. The overall trend suggested that the apoptotic effect in the follicular fluid of the EZTG group was downregulated.

Conclusion

Treatment with the EZTG granule can improve embryo quality in IVF of advanced age females with both kidney Qi and Yin deficiency syndromes. The mechanism is attributed to downregulation of apoptotic-effector protein expressions in the follicular fluid. This trial is registered with ChiCTR1900025139.

Reproductive aging and telomeres: Are women and men equally affected?

Successful reproduction is very important for individuals and for society. Currently, the human health span and lifespan are the object of intense and productive investigation with great achievements, compared to the last century. However, reproduction span does not progress concomitantly with lifespan. Reproductive organs age, decreasing the levels of sexual hormones, which are protectors of health through their action on several organs of the body. Thus, this is the starting point of the organismal decay and infertility. This starting point is easily detected in women. In men, it goes under the surface, undetected, but it goes, nevertheless. Regarding fertility, aging alters the hormonal equilibrium, decreases the potential of reproductive organs, diminishes the quality of the gametes and worsen the reproductive outcomes. All these events happen at a different pace and affecting different organs in women and men. The question is what molecular pathways are involved in reproductive aging and if there is a possible halting or even reversion of the aging events. Answers to all these points will be explained in the present review.

A Nuclear and Cytoplasmic Characterization of Bovine Oocytes Reveals That Cysteamine Partially Rescues the Embryo Development in a Model of Low Ovarian Reserve

Simple Summary

Women’s reproductive performance starts declining in the mid-30s, and by age 40–45, the possibility of becoming pregnant becomes very small. Reproductive aging is a physiological process of fertility decline characterized by a decrease in quality and stockpile of eggs (also called ovarian reserve) in most mammals. However, young individuals too can show an accelerated reproductive aging that similarly results in a low ovarian reserve and hypofertility. This syndrome, called premature ovarian failure (POF), is becoming a relevant problem due to the general tendency to postpone the first pregnancy. In this study, we used bovine ovaries that were classified in two categories, according to the number of follicles visible on the ovarian surface, and analyzed some parameters of egg maturation. We observed that eggs from the ‘aging-like’ ovaries carry several defects that impair maturation. However, one of the parameters was improved upon supplementation with a scavenger of free radicals, providing a proof of concept that in-depth knowledge of the cellular mechanisms is essential to find solutions to everyday-life problems.

Abstract

Decreased oocyte quality is a major determinant of age-associated fertility decline. Similarly, individuals affected by early ovarian aging carry low-quality oocytes. Using an established bovine model of early ovarian aging, we investigated key features of ‘quality’ oocyte maturation, associated with the onset of egg aneuploidy and reproductive aging, such as histone modifications, mitochondria distribution and activity, reduced glutathione (GSH) content, and gap junction functionality. Bovine ovaries were classified according to the antral follicle count (AFC), and the retrieved oocytes were processed immediately or matured in vitro. We observed alterations in several cellular processes, suggesting a multifactorial etiology of the reduced oocyte quality. Furthermore, we performed a rescue experiment for one of the parameters considered. By adding cysteamine to the maturation medium, we experimentally increased the free radical scavenger ability of the ‘low competence’ oocytes and obtained a higher embryo development. Our findings show that adopting culture conditions that counteract the free radicals has a positive impact on the quality of ‘compromised’ oocytes. Specifically, cysteamine treatment seems to be a promising option for treating aging-related deficiencies in embryo development.

Recombinant human luteinizing hormone co-treatment in ovarian stimulation for assisted reproductive technology in women of advanced reproductive age: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Several studies suggest that luteinizing hormone (LH) could improve IVF outcome in women of advanced reproductive age by optimizing androgen production. In this review, we assessed the role of recombinant-human LH (r-hLH) and recombinant human follicle stimulating hormone (r-hFSH) co-treatment in ovarian stimulation for assisted reproductive technology in women of advanced reproductive age candidates for assisted reproduction.

MATERIAL AND METHODS

Using a preregistered protocol we systematically searched Medline/PubMed, Scopus and the ISI Web of Science databases to identify randomized controlled trials in which r-hFSH monotherapy protocols were compared with r-hFSH/r-hLH co-treatment in women ≥35 years undergoing fresh IVF cycles. We calculated the pooled odds ratio (OR) for dichotomous data and the weight mean difference (WMD) for continuous data with an associated 95% confidence interval (CI). The meta-analyses were conducted using the random-effect model. P values < 0.05 were considered statistically significant. Subgroup analyses of all primary and secondary outcomes were performed only in women aged 35-40 years.

RESULTS

Twelve studies were identified. In women aged between 35 and 40 years, r-hFSH/r-hLH co-treatment was associated with higher clinical pregnancy rates (OR 1.45, CI 95% 1.05-2.00, I² = 0%, P = 0.03) and implantation rates (OR 1.49, CI 95% 1.10-2.01, I² = 13%, P = 0.01) versus r-hFSH monotherapy. Fewer oocytes were retrieved in r-hFSH/r-hLH-treated patients than in r-hFSH-treated patients both in women aged ≥35 years (WMD -0.82 CI 95% -1.40 to - 0.24, I² = 88%, P = 0.005) and in those aged between 35 and 40 years (WMD -1.03, CI - 1.89 to - 0.17, I² = 0%, P = 0.02). The number of metaphase II oocytes, miscarriage rates and live birth rates did not differ between the two groups of women overall or in subgroup analysis.

CONCLUSION

Although more oocytes were retrieved in patients who underwent r-hFSH monotherapy, this meta-analysis suggests that r-hFSH/r-hLH co-treatment improves clinical pregnancy and implantation rates in women between 35 and 40 years of age undergoing ovarian stimulation for assisted reproduction technology. However, more RCTs using narrower age ranges in advanced age women are warranted to corroborate these findings.

Fecundability and Sterility by Age: Estimates Using Time to Pregnancy Data of Japanese Couples Trying to Conceive Their First Child with and without Fertility Treatment

Fecundability, the probability of conception in a month or in a menstrual cycle, varies across and within age groups for both women and men. Fertility treatment has become common in a number of countries including Japan, but its impact on the age pattern of fecundability is unknown. By utilizing the previously collected data on time to pregnancy (TTP) of Japanese couples trying to conceive their first child, the present study aimed to estimate fecundability and sterility by women’s age and to assess how the estimates may differ by including or excluding assisted conceptions. Duration between discontinuing contraception and conception (including both natural and assisted) resulted in a live birth was called TTP-all, and the duration ending with natural conception was called TTP-natural. TTP-natural was censored when a participant received fertility consultation or treatment. A zero-inflated beta distribution model was used to estimate a proportion of sterile (zero probability of conception) and a distribution of fecundability for each age group. Parameters of the distribution were estimated using the maximum likelihood method. When TTP-all and TTP-natural were used, the sterile proportion of the whole sample was, respectively, 2% and 14%, and the median (interquartile range) of fecundability was, respectively, 0.10 (0.04, 0.19) and 0.11 (0.05, 0.19). The median (interquartile range) of fecundability was 0.18 (0.10, 0.29) for women aged 24 years or younger and 0.05 (0.02, 0.13) for 35–39 years old when TTP-all was used, and the estimates were quite similar with those based on TTP-natural: it was 0.18 (0.10, 0.29) for women aged 24 years or younger and 0.06 (0.00, 0.15) for 35–39 years old. Exclusion of assisted conceptions resulted in larger proportions of sterility, but it had little impact on median or interquartile ranges of fecundability estimates. Fecundability is overall lower at higher ages, while interquartile ranges are overlapping, suggesting that inter-individual variability of fecundability within an age group is as large as the variability across age groups.

Longevity pathways are associated with human ovarian ageing

STUDY QUESTION

Are genes known to be involved in somatic cell ageing, particularly related to longevity pathways, associated with the accelerated ageing process of the ovary?

SUMMARY ANSWER

Growth, metabolism, and cell-cycle progression-related pathways that are involved in somatic cell ageing are also associated with ovarian ageing.

WHAT IS KNOWN ALREADY

Ovarian ageing is characterized by a gradual decline in ovarian follicle quantity, a decline in oocyte quality, and lower chances of pregnancy. Genetic pathways modulating the rate of somatic cell ageing have been researched intensively. Ovarian ageing does not follow the same timeline as somatic cell ageing, as signs of ovarian ageing occur at a younger female age, while the somatic cells are still relatively young. It is not known whether the generally recognized somatic cell longevity genes also play a role during ovarian ageing. Looking at somatic cell longevity genes can lead to new hypotheses and possible treatment options for subfertility caused by ovarian ageing.

STUDY DESIGN, SIZE, DURATION

In this observational study, we analysed a dataset of individual gene expression profiles of 38 germinal vesicle (GV) oocytes from 38 women aged between 25 and 43 years. We correlated female age (calendar age in years) and biological age (factors known to be associated with ovarian ageing such as dosage of FSH needed for ovarian hyperstimulation, and antral follicle count (AFC)) with gene expression signatures of longevity pathways.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Transcripts of 38 GV oocytes were used for individual gene expression analysis. R version 3.5.1 was used to process and analyse data. The GeneAge database (build 19) was used to obtain mouse ageing-related genes. Human to mouse orthologues were obtained using the R package biomaRt. Correlations and significance between gene expression data and age were tested for using Pearson's product moment correlation coefficient using ranked expression data. Distributions were compared with an ANOVA, and the Tukey Honest Significant Difference method was used to control for the Type I error rate across multiple comparisons.

MAIN RESULTS AND THE ROLE OF CHANCE

Of the 136 genes in the GeneAge database, the expression of 15 anti-longevity genes identified in oocytes showed a positive correlation with female calendar age and FSH dosage administered during ICSI treatment, and a negative correlation with AFC. Expression of 32 pro-longevity genes was negatively correlated with calendar age and FSH dosage, and positively correlated with AFC. In general, anti- and pro-longevity genes changed in opposing directions with advancing maternal age in oocytes. Notably, the anti-longevity genes include many ‘growth’-related genes involved in the mechanistic target of rapamycin (mTOR) Complex 1 pathway, such as EIF5A2, EIF3H, EIF4E, and mTOR. The pro-longevity genes include many cell-cycle progression-related genes involved in DNA damage repair (e.g. XRCC6, ERCC2, and MSH2) or cell-cycle checkpoint regulation genes (e.g. ATM, BRCA1, TP53, TP63, TP73, and BUB1B).

LIMITATIONS, REASONS FOR CAUTION

Using mature oocytes instead of GV-stage oocytes discarded from ICSI treatments may provide different results. No correction for multiple testing was carried out on individual genes because a small set of longevity-related genes was selected a priori for the analysis. The global trend was corrected for multiple testing and remained significant. This work was an observational study and, as no additional experimental work was performed, the associations described do not directly demonstrate the involvement of such genes in oocyte ageing.

WIDER IMPLICATIONS OF THE FINDINGS

Growth, metabolism, and cell-cycle progression-related pathways that are known to be involved in somatic cell ageing were associated with ovarian ageing. If experimental data are obtained to support these associations, we suggest that interventions known to modulate these processes could benefit women suffering from ovarian ageing.

STUDY FUNDING/COMPETING INTEREST(S)

G.E.J. is supported by a VENI grant from ZonMw (https://www.zonmw.nl). Work in the Houtkooper group is financially supported by an ERC Starting grant (No. 638290), a VIDI grant from ZonMw (No. 91715305), and the Velux Stiftung (No. 1063). M.G. declares several research and educational grants from Guerbet, Merck and Ferring (all location VUmc), outside the scope of the submitted work. The other authors report no competing interest

TRIAL REGISTRATION NUMBER

N/A.

Epigenetic clock and methylation study of oocytes from a bovine model of reproductive aging

Cattle are an attractive animal model of fertility in women due to their high degree of similarity relative to follicle selection, embryo cleavage, blastocyst formation, and gestation length. To facilitate future studies of the epigenetic underpinnings of aging effects in the female reproductive axis, several DNA methylation-based biomarkers of aging (epigenetic clocks) for bovine oocytes are presented. One such clock was germane to only oocytes, while a dual-tissue clock was highly predictive of age in both oocytes and blood. Dual species clocks that apply to both humans and cattle were also developed and evaluated. These epigenetic clocks can be used to accurately estimate the biological age of oocytes. Both epigenetic clock studies and epigenome-wide association studies revealed that blood and oocytes differ substantially with respect to aging and the underlying epigenetic signatures that potentially influence the aging process. The rate of epigenetic aging was found to be slower in oocytes compared to blood; however, oocytes appeared to begin at an older epigenetic age. The epigenetic clocks for oocytes are expected to address questions in the field of reproductive aging, including the central question: how to slow aging of oocytes.

Late, But Not Too Late? Postponement of First Birth Among Highly Educated US Women

We examine the link between the postponement of parenthood and fertility outcomes among highly educated women in the USA born in 1920–1986, using data from the CPS June Supplement 1979–2016. We argue that the postponement–low fertility nexus noted in demographic and biomedical research is especially relevant for women who pursue postgraduate education because of the potential overlap of education completion, early career stages, and family formation. The results show that women with postgraduate education differ from women with college education in terms of the timing of the first birth, childlessness, and completed fertility. While the postponement trend, which began with the cohorts born in the 1940s, has continued among highly educated women in the USA, its associations with childlessness and completed parity have changed considerably over subsequent cohorts. We delineate five distinct postponement phases over the 80-year observation window, consistent with variation over time in the prevalence of strategies for combining tertiary education and employment with family formation.

Circular RNAs: Novel potential regulators in embryogenesis, female infertility, and pregnancy-related diseases

Circular RNAs (circRNAs) are endogenous noncoding RNAs with unique cyclic structures. Although they were previously considered as nonfunctional transcription byproducts, numerous studies have demonstrated that circRNAs regulate gene transcription and expression via different mechanisms. Reproductive health influences the quality of life and affects offspring propagation in women. CircRNAs have been found to modify pregnancy-related diseases, gynecologic cancers, polycystic ovary syndrome, aging, gamete, and embryo development. It's promising for circRNAs to be the novel diagnostic and therapeutic targets for multiple reproductive diseases. With the widespread application of assisted reproduction technology (ART), it has been revealed that circRNA identification contributes to estimating the quality of gametes and embryos, reflecting the success rate of ART. CRISPR-Cas9 gene editing technology has enabled the discovery of new roles of circRNAs. So far, the roles of circRNAs in the reproductive system remain poorly defined. In this review, we describe the classification and functions of circRNAs in embryogenesis and the female reproductive system diseases, revealing potential roles of circRNAs physiologically and pathologically. In so-doing, we provide ideas for developing circRNA-based therapeutic treatment and clinical application of various female reproductive system diseases.

Uterine Insulin Sensitivity Defects Induced Embryo Implantation Loss Associated with Mitochondrial Dysfunction-Triggered Oxidative Stress

Methods and Results

Herein, a comprehensive proteomic analysis was conducted on proliferative endometria from sows with low and normal reproductive performance (LRP and NRP, respectively). Enrichment analysis of differentially expressed proteins revealed alterations in endometrial remodeling, substance metabolism (mainly lipid, nitrogen, and retinol metabolism), immunological modulation, and insulin signaling in LRP sows. Importantly, aberrant lipid metabolite accumulation and dysregulation of insulin signaling were coincidently confirmed in endometria of LPR sows, proving an impaired insulin sensitivity. Furthermore, established high-fat diet- (HFD-) induced insulin-resistant mouse models revealed that uterine insulin resistance beginning before pregnancy deteriorated uterine receptivity and decreased implantation sites and fetal numbers. Mitochondrial biogenesis and fusion were decreased, and reactive oxygen species was overproduced in uteri from the HFD group during the implantation period. Ishikawa and JAR cells directly demonstrated that oxidative stress compromised implantation in vitro.

Conclusions

This study demonstrated that uterine insulin sensitivity impairment beginning before pregnancy resulted in implantation and fetal loss associated with oxidative stress induced by mitochondrial dysfunction.

Understanding oocyte ageing: can we influence the process as clinicians?

PURPOSE OF REVIEW

Oocyte quality is rate-limiting for pregnancy success and declines with age. Here, I review animal-study evidence showing dramatic reversal of oocyte ageing with mitochondrial nutrients and explore clinical evidence related to their usage.

RECENT FINDINGS

Oocyte ageing is strongly tied to mitochondrial dysfunction and oxidative stress. Quality-defining events occur over a protracted period (2-3 months in humans) when oocyte volume increases over 100-fold. Treating mice during the growth phase with mitochondrial modifiers such as CoQ10 combats oocyte ageing. Exciting new work shows that raising oocyte NAD+ levels also dramatically rejuvenate aged oocytes. However, evidence that any of these agents can reproducibly improve quality in humans is lacking. This is largely because there has been a focus on patients with poor ovarian response during IVF and/or low ovarian follicular pool size, rather than patients with poor oocyte quality. In addition, studies have used short-term treatment during ovarian stimulation after oocyte growth is already complete.

SUMMARY

Mitochondrial therapeutics such as NAD+-boosting used during the oocyte's growth phase markedly improve oocyte quality in mice. Evaluating them in humans should focus on patients with poor oocyte quality and utilise per-oocyte (rather than per-cycle) endpoints after adequate treatment that captures the growth phase when quality is defined.

Glutathione ethyl ester improved the age-induced decline in the developmental competence of bovine oocytes

The aberrant redox regulation and anti-oxidative defense is one of the main causes of age-induced decline in oocytes quality and embryo development in mammals. The present study aimed to elucidate the effect of glutathione ethyl ester (GSH-OEt), a cell-permeable glutathione (GSH) donor, on the developmental competence of oocytes in cows with advanced reproductive age. Oocytes were collected from cows aged 30-50 months or >120 months, which were defined as young or aged, respectively, and subjected to in vitro maturation (IVM) in the presence of 5 mM of GSH-OEt. In aged cows, the GSH level in follicular fluid was lower, and the intracellular levels of reactive oxygen species (ROS) in post-IVM oocytes was higher than those in young cows. GSH-OEt supplementation during IVM reduced the ROS contents of oocyte in aged cows but not in young cows. GSH-OEt treatment promoted the meiotic progression and increased the proportion of oocytes with mature cytoplasm containing evenly dispersed cortical granules in aged cows. After in vitro fertilization, the normal fertilization and development to the blastocyst stage were enhanced by GSH-OEt in aged cows to levels comparable to those in young cows. Further, oocyte maturation in the presence of GSH-OEt increased the proportion of diploid blastocyst in aged cows. In contrast, GSH-OEt failed to enhance the oocyte maturation, fertilization, and embryo development in young cows. Taken together, the exogenous supplementation of GSH-OEt during IVM modulated the age-related oxidative damage of bovine oocytes and improved the developmental competence of oocytes in aged cows. Oocytes presented a distinct response to GSH-OEt treatment depending on the donor age. GSH-OEt supplementation during IVM could be of practical value through the efficiency improvement of chromosomally normal embryo production in aged cows.

The predictive value of serial serum estradiol and serial endometrial volume on endometrial receptivity on assisted reproductive technology cycles

Background

Diagnosis of endometrial receptivity is still unclear and conflicting. Despite advances in embryo development during assisted reproductive technologies (ART) cycles, the intricate process of implantation is still matter for debate and research.

Materials and methods

Prospective case control of 169 subjects during ovarian controlled stimulation for ART. Endometrial receptivity assessment to predict clinical pregnancy with serial continuous biochemical (serum estradiol) and biophysical (endometrial volume and adjusted endometrial volume) parameters were used. Both parameters were compared between negative and positive outcome in terms of clinical pregnancy.

Results

No statistical difference was noted between the two groups in terms of demographics and ART procedures and scores. Serum estradiol was significantly higher in the positive group from day 8 after ovarian controlled stimulation. Endometrial volume and adjusted endometrial volume were significantly higher in the positive group as soon as day 6 of ovarian controlled stimulation.

Conclusions

Continuous serum estradiol and 3D endometrial volume and adjusted endometrial volumes may reflect endometrial changes during ART procedures and provide a useful real time tool for clinicians in predicting endometrial receptivity.