Prevention of ovarian hyperstimulation syndrome (OHSS): British Fertility Society policy and practice guideline

This British Fertility Society (BFS) Policy and Practice guideline aims to support clinicians in preventing ovarian hyperstimulation syndrome (OHSS) in patients undergoing gonadotropin ovarian stimulation. A systematic literature search of the medical databases was performed. The Guideline Development Group (GDG) identified the risk factors of OHSS before and during ovarian stimulation. The relation of different pre-treatment measures and different ovarian stimulation protocols with OHSS was evaluated. The optimal monitoring during treatment was assessed. The current evidence on preventive strategies during and after ovarian stimulation and the available adjuvant preventive agents were examined. Based on this, the GDG developed evidence-based, graded recommendations for clinical practice. The evidence was evaluated within context, considering the effectiveness, cost and practical problems of assisted reproductive technology for patients and healthcare providers. Early identification and application of preventive measures identified in this guideline may reduce the incidence of OHSS or reduce its severity. Suggestions for future research on OHSS prevention are provided.

Characterization of H3K4me3 in mouse oocytes at the metaphase II stage

Central functions of histone modifications in germ cell and embryonic development have been documented. Accumulating evidence suggests that oocytes possess unique profiles of histone modifications, among which histone H3 lysine 4 trimethylation (H3K4me3) is broadly spread on the mouse oocyte chromosomes at the metaphase II (MII) stage, unlike later embryonic stages. However, the characteristics and developmental roles of H3K4me3 on MII chromosomes are unclear. Here, we discovered that H3K4me3 was abundantly localized on some of the MII oocyte chromosomes facing the cortical side. Using multicolor FISH and CRISPR-Sirius-based labeling of chromosomes, we revealed that the X chromosome tended to be localized at the cortical side with strong H3K4me3 signals. Anchoring oocyte chromosomes to the cortex may play a role in the asymmetric H3K4me3 distribution. Furthermore, we found that the forced removal of H3K4me3 through the overexpression of a specific lysine demethylase in MII oocytes resulted in abnormal chromosome-spindle structure and impaired preimplantation development after in vitro fertilization. These findings highlight the developmental function of H3K4me3 in transcriptionally-silent MII oocytes.

Human Cervix Chip: A Preclinical Model for Studying the Role of the Cervical Mucosa and Microbiome in Female Reproductive Health

Advancements in women's reproductive health have been hindered by insufficient knowledge and the underrepresentation of women in research, leading to symptom-focused care with poor outcomes. Modeling female reproductive biology and disease pathophysiology has been challenging due to the complexity and dynamic nature of the female organs. Here, we briefly review recent advancements made with a new in vitro microfluidic organ-on-a-chip model of the human cervix (Cervix Chip) that faithfully mimics key features of the cervix, including mucus production and physiological responses to hormonal, environmental, and microbial stimuli. We also discuss how this preclinical platform can provide a way to obtain unique insights into the role of mucosal immunity, genetic and risk factors, as well as microbiome and pathogen interactions in human cervix health and disease, while bridging knowledge gaps in fertility and pregnancy-related conditions. By enabling preclinical drug screening and accelerating translational research, the Cervix Chip holds the potential to improve the development of therapeutics, diagnostics, and ultimately, the sexual and reproductive health of millions of women globally.

Therapeutic implications of mitochondrial transfer on stem cell fate in regenerative medicine

With the discovery of intercellular mitochondrial transfer, the intricate mitochondrial regulatory networks on stem cell fate have aroused intense academic interest. Apart from capturing freely released mitochondria from donor cells, stem cells are able to receive mitochondria through tunneling nanotubes (TNTs), gap junctional channels (GJCs) and extracellular vesicles (EVs), especially when undergoing stressful conditions such as inflammation, hypoxia, chemotherapy drug exposure, and irradiation. Stem cells that are potentiated by exogenous mitochondria show enhanced potential for proliferation, differentiation, and immunomodulation. The well-tolerated nature of either autogenous or allogenous mitochondria when locally injected in the human ischemic heart has validated the safety and therapeutic potential of mitochondrial transplantation. In children diagnosed with mitochondrial DNA deletion syndrome, functional improvements have been observed when empowering their hematopoietic stem cells with maternally derived mitochondria. Apart from the widely investigated applications of mitochondrial transfer in ischemia-reperfusion injury, neurodegenerative diseases and mitochondrial diseases etc., therapeutic potentials of mitochondrial transfer in tissue repair and regeneration are equally noteworthy, though there has been no systematic summary in this regard.This review analyzed the research and development trends of mitochondrial transfer in stem cells and regenerative medicine over the past decade from a bibliometric perspective, introduced the concept and associated mechanisms of mitochondrial transfer, summarized the regulations of intercellular mitochondrial transfer on stem cell fate. Finally, the therapeutic application of mitochondrial transplantation in diseases and tissue regeneration has been reviewed, including recent clinical studies related to mitochondrial transplantation.Mitochondrial transfer shows promise in modifying and reshaping the cellular properties of stem cells, making them more conducive to regeneration. Mesenchymal stem cells (MSCs)-derived mitochondria have shown multifaceted potential in promoting the revitalization and regeneration of cardiac, cutaneous, muscular, neuronal tissue. This review integrates novel research findings on mitochondrial transfer in stem cell biology and regenerative medicine, emphasizing the crucial translational value of mitochondrial transfer in regeneration. It serves to underscore the significant impact of mitochondrial transfer and provides a valuable reference for further exploration in this field.

Nicotinamide riboside supplementation protects against maternal diabetes-associated decline in oocyte quality

In brief

NAD+ levels were reduced in streptozotocin (STZ)-induced diabetic mice, but nicotinamide riboside (NR) supplementation improved these levels in diabetic ovaries and oocytes, enhancing oocyte quality and early embryo development by improving mitochondrial function and lowering reactive oxygen species (ROS) levels.

Abstract

Diabetes mellitus is strongly correlated with a decline in oocyte quality; however, noninvasive and effective methods to improve this issue have yet to be fully development. Here, we demonstrate that in vivo supplementation with NR 400 mg/kg/day for 14 days effectively enhances the quality of oocytes from diabetic mice induced by streptozocin 190 mg/kg by restoring nicotinamide adenine dinucleotide (NAD+) levels. NR supplementation not only improved superovulation function of diabetic mice but also improved their oocyte quality and embryonic development potential after fertilization by maintaining normal spindle structure and alleviating mitochondrial dysfunction. In addition, NR supplementation reduced ROS levels in oocytes from diabetic mice. Overall, our findings suggest that dietary NR supplementation is a viable strategy to protect oocytes from diabetes-related deterioration, thereby enhancing reproductive outcomes in maternal diabetes and improving the efficacy of assisted reproductive technology.

Mitochondrial Quality Control in Ovarian Function: From Mechanisms to Therapeutic Strategies

Mitochondrial quality control plays a critical role in cytogenetic development by regulating various cell-death pathways and modulating the release of reactive oxygen species (ROS). Dysregulated mitochondrial quality control can lead to a broad spectrum of diseases, including reproductive disorders, particularly female infertility. Ovarian insufficiency is a significant contributor to female infertility, given its high prevalence, complex pathogenesis, and profound impact on women's health. Understanding the pathogenesis of ovarian insufficiency and devising treatment strategies based on this understanding are crucial. Oocytes and granulosa cells (GCs) are the primary ovarian cell types, with GCs regulated by oocytes, fulfilling their specific energy requirements prior to ovulation. Dysregulation of mitochondrial quality control through gene knockout or external stimuli can precipitate apoptosis, inflammatory responses, or ferroptosis in both oocytes and GCs, exacerbating ovarian insufficiency. This review aimed to delineate the regulatory mechanisms of mitochondrial quality control in GCs and oocytes during ovarian development. This study highlights the adverse consequences of dysregulated mitochondrial quality control on GCs and oocyte development and proposes therapeutic interventions for ovarian insufficiency based on mitochondrial quality control. These insights provide a foundation for future clinical approaches for treating ovarian insufficiency.

The influence and mechanisms of exogenous aryl hydrocarbon receptor ligands on the viability of mouse germ cells

Environmental pollution is a significant contributor to male infertility. Numerous environmental pollutants, such as PCB118, act as exogenous ligands for the aryl hydrocarbon receptor (AhR). However, the role of AhR in mediating the effects of environmental pollutants on male reproductive functions remains inadequately understood. In the present study, we assessed the viability of GC-1 and GC-2 cells using the CCK-8 assay. Immunofluorescence and Western blotting techniques were employed to investigate the distribution and protein expression levels of AhR within these cell lines. Alterations in reactive oxygen species (ROS) levels and mitochondrial membrane potential (MMP) were evaluated using DCFH-DA dye and the JC-1 assay, respectively. Furthermore, we investigated changes in the expression levels of Nrf2, Cleaved-Caspase 3, Cleaved-Caspase 8, Bcl-2, and Bax through Western blot analysis. Our findings indicate that PCB118 and the AhR-specific agonist CAY10465 diminish the viability of GC-1 and GC-2 cells, facilitate the nuclear translocation and expression of AhR protein, elevate ROS levels, and reduce MMP. Moreover, these agents markedly increase the levels of Cleaved-Caspase 3 and Cleaved-Caspase 8 while decreasing the Bax/Bcl-2 ratio. Notably, the AhR antagonist CH223191 and resveratrol have the capacity to restore the functionality of GC-1 and GC-2 cells by mitigating the effects of PCB118 and CAY10465. Based on these observations, we propose that exogenous AhR ligands PCB118 and CAY10465 promote the nuclear translocation and upregulation of AhR expression in GC-1 and GC-2 cells. This process subsequently induces mitochondrial oxidative stress, wich activates the apoptotic signaling pathway and ultimately compromises cellular viability.

Optimization of culture-preservation methods to maintain developmental competence in porcine metaphase II (MII) oocytes post-in vitro maturation (IVM)

After in vitro maturation (IVM) of porcine germinal vesicle (GV) oocytes, those that matured to the metaphase II (MII) stage were selected for further culture over a period of 24-48 h. Subsequently, these oocytes were either parthenogenetically activated or used for somatic cell nuclear transfer (SCNT) to evaluate their in vitro developmental competence. Parthenogenetically activated MII oocytes developed to the blastocyst stage after 42 h of continuous culture, whereas SCNT oocytes reached the blastocyst stage within 30 h of culture. These findings suggest that porcine MII oocytes retain their developmental competence after extended in vitro culture exceeding 30 h. This study highlights the potential of prolonged culture in enhancing the utility of MII-stage oocytes for livestock applications and possibly for future advancements in human infertility treatments.

The chromosomal challenge of human embryos: Mechanisms and fundamentals

Chromosomal abnormalities in human pre-implantation embryos, originating from either meiotic or mitotic errors, present a significant challenge in reproductive biology. Complete aneuploidy is primarily linked to errors during the resumption of meiosis in oocyte maturation, which increase with maternal age, while mosaic aneuploidies result from mitotic errors after fertilization. The biological causes of these abnormalities are increasingly becoming a topic of interest for research groups and clinical specialists. This review explores the intricate processes of meiotic and early mitotic divisions in embryos, shedding light on the mechanisms that lead to changes in chromosome number in daughter cells. Key factors in meiotic division include difficulties in spindle assembly without centrosomes, kinetochore (KT) orientation disturbances, and inefficient cell-cycle checkpoints. The weakening of cohesion molecules that bind chromosomes, exacerbated by maternal aging, further complicates chromosomal segregation. Mitotic errors in early development are influenced by defects in sperm centrosomes, KT misalignment, and the gradual depletion of maternal regulatory factors. Coupled with the inactive or partially active embryonic genome, this depletion increases the likelihood of chromosomal aberrations. While various theoretical mechanisms for these abnormalities exist, current data remain insufficient to determine their exact contributions. Continued research is essential to unravel these complex processes and improve outcomes in assisted reproductive technologies.

Luteinizing Hormone Regulates Testosterone Production, Leydig Cell Proliferation, Differentiation, and Circadian Rhythm During Spermatogenesis

Male reproductive health, particularly the regulation of spermatogenesis, is controlled by a complex combination of factors, including luteinizing hormone (LH) and its effects on Leydig cells (LCs). LH stimulates testosterone synthesis in LCs, which is critical for maintaining spermatogenesis and male fertility. This review examines the pathways through which LH regulates testosterone production, LC proliferation, differentiation, and circadian rhythm in human and non-human species. In particular, the signaling pathways of luteinizing hormone involved in testosterone production are discussed. Additionally, we explore LH's role in sperm maturation and quality, emphasizing its clinical implications in treating hypogonadotropic hypogonadism and diagnosing gonadal dysfunctions such as androgen insensitivity syndrome and precocious puberty. Furthermore, the potential of LH in assisted reproductive technologies for improving sperm quality is discussed. By highlighting key molecular mechanisms, this work provides insights into the therapeutic potential of LH in addressing male infertility and conditions of LC dysfunction.

The Complexities of Interspecies Somatic Cell Nuclear Transfer: From Biological and Molecular Insights to Future Perspectives

For nearly three decades, interspecies somatic cell nuclear transfer (iSCNT) has been explored as a potential tool for cloning, regenerative medicine, and wildlife conservation. However, developmental inefficiencies remain a major challenge, largely due to persistent barriers in nucleocytoplasmic transport, mitonuclear communication, and epigenome crosstalk. This review synthesized peer-reviewed English articles from PubMed, Web of Science, and Scopus, spanning nearly three decades, using relevant keywords to explore the molecular mechanisms underlying iSCNT inefficiencies and potential improvement strategies. We highlight recent findings deepening the understanding of interspecies barriers in iSCNT, emphasizing their interconnected complexities, including the following: (1) nucleocytoplasmic incompatibility may disrupt nuclear pore complex (NPC) assembly and maturation, impairing the nuclear transport of essential transcription factors (TFs), embryonic genome activation (EGA), and nuclear reprogramming; (2) mitonuclear incompatibility could lead to nuclear and mitochondrial DNA (nDNA-mtDNA) mismatches, affecting electron transport chain (ETC) assembly, oxidative phosphorylation, and energy metabolism; (3) these interrelated incompatibilities can further influence epigenetic regulation, potentially leading to incomplete epigenetic reprogramming in iSCNT embryos. Addressing these challenges requires a multifaceted, species-specific approach that balances multiple incompatibilities rather than isolating a single factor. Gaining insight into the molecular interactions between the donor nucleus and recipient cytoplast, coupled with optimizing strategies tailored to specific pairings, could significantly enhance iSCNT efficiency, ultimately transforming experimental breakthroughs into real-world applications in reproductive biotechnology, regenerative medicine, and species conservation.

Updating the Role of JUNO and Factors Involved in Its Function during Fertilization

INTRODUCTION

The final step of the fertilization process involves gametes adhesion and fusion. JUNO is an essential folate receptor 4 protein present in the ooplasm of oocytes, which binds to IZUMO1, its receptor on the sperm surface. Both proteins are indispensable for the sperm-oocyte interaction, and their absence results in infertility. Despite the importance of JUNO in reproduction, there is still controversy about how different factors affect the functionality of JUNO. Therefore, the goal of this study was to provide a comprehensive overview of what we know so far about the presence and functionality of JUNO.

METHODS

In order to accomplish this, a total of 198 articles were identified. Based on both inclusion and exclusion criteria, 40 articles were finally included in this study.

RESULTS

The results showed that during oocyte maturation, the expression levels of JUNO undergo alterations and, in some instances, cross-species gamete fusion is possible. Additionally, it has been observed that exposure of oocytes to factors such as bisphenol A, 17α-ethynylestradiol, diazinon, benzo(a)pyrene, butylparaben, bis(2-ethylhexyl) phthalate, hydroxyurea, dichlorophenol, isoniazid, and para-phenylenediamine disrupt JUNO and decrease the fertilization process rates. Moreover, exposure to ionic radiation, vitrification, and synthetic materials as microplastics has the same effect. Nonetheless, other compounds such as melatonin, mogroside V, cholesterol-loaded methyl-β-cyclodextrin, methyl-β-cyclodextrin, protocatechuic acid, coenzyme Q10, resveratrol, and Shoutai pills have been shown to enhance female fertility in terms of JUNO functionality.

CONCLUSION

In summary, this update highlights the crucial role of JUNO during fertilization and reveals how different factors and experimental procedures affect its activity.

Nutrigenetic and Epigenetic Mechanisms of Maternal Nutrition-Induced Glucolipid Metabolism Changes in the Offspring

Maternal nutrition during pregnancy regulates the offspring's metabolic homeostasis, including insulin sensitivity and the metabolism of glucose and lipids. The fetus undergoes a crucial period of plasticity in the uterus; metabolic changes in the fetus during pregnancy caused by maternal nutrition not only influence fetal growth and development but also have a long-term or even life-long impact for the offspring. Epigenetic modifications, such as DNA methylation, histone modification, and non-coding RNAs, play important roles in intergenerational and transgenerational effects. In this context, this narrative review comprehensively summarizes and analyzes the molecular mechanisms underlying how maternal nutrition, including a high-fat diet, polyunsaturated fatty acid diet, methyl donor nutrient supplementation, feed restriction, and protein restriction during pregnancy, impacts the genes involved in glucolipid metabolism in the liver, adipose tissue, hypothalamus, muscle, and oocytes of the offspring in terms of the epigenetic modifications. This will provide a foundation for the further exploration of nutrigenetic and epigenetic mechanisms for integrative mother-child nutrition and promotion of the offspring's health through the regulation of maternal nutrition during pregnancy. Note: This paper is part of the Nutrition Reviews Special Collection on Precision Nutrition.

Mitochondrial replacement techniques to resolve mitochondrial dysfunction and ooplasmic deficiencies: where are we now?

Mitochondria are the powerhouses of cell and play crucial roles in proper oocyte competence, fertilization, and early embryo development. Maternally inherited mitochondrial DNA (mtDNA) mutations can have serious implications for individuals, leading to life-threatening disorders and contribute to ovarian ageing and female infertility due to poor oocyte quality. Mitochondrial replacement techniques (MRTs) have emerged as a promising approach not only to replace defective maternal mitochondria in patients carrying mtDNA mutations, but also to enhance oocyte quality and optimize IVF outcomes for individuals experiencing infertility. There are two main categories of MRT based on the source of mitochondria. In the heterologous approach, mitochondria from a healthy donor are transferred to the recipient's oocyte. This approach includes several methodologies such as germinal vesicle, pronuclear, maternal spindle, and polar body transfer. However, ethical concerns have been raised regarding the potential inheritance of third-party genetic material and the development of heteroplasmy. An alternative approach to avoid these issues is the autologous method. One promising autologous technique was the autologous germline mitochondrial energy transfer (AUGMENT), which involved isolating oogonial precursor cells from the patient, extracting their mitochondria, and then injecting them during ICSI. However, the efficacy of AUGMENT has been debated following the results of a randomized clinical trial (RCT) that demonstrated no significant benefit over conventional IVF. Recent developments have focused on novel approaches based on autologous, non-invasively derived stem cells to address infertility. While these techniques show promising results, further RCTs are necessary to establish their effectiveness and safety for clinical use. Only after robust evidence becomes available could MRT potentially become a viable treatment option for overcoming infertility and enabling patients to have genetically related embryos. This review aims to provide an overview of the current state of MRTs in addressing low oocyte quality due to mitochondrial dysfunction.

Caloric restriction prevents inheritance of polycystic ovary syndrome through oocyte-mediated DNA methylation reprogramming

Polycystic ovary syndrome (PCOS) is a prevalent metabolic and reproductive endocrine disorder with strong heritability. However, the independent role of oocytes in mediating this heritability remains unclear. Utilizing in vitro fertilization-embryo transfer and surrogacy, we demonstrated that oocytes from androgen-exposed mice (F1) transmitted PCOS-like traits to F2 and F3 generations. Notably, caloric restriction (CR) in F1 or F2 effectively prevented this transmission by restoring disrupted DNA methylation in oocyte genes related to insulin secretion and AMPK signaling pathways. Further detection in adult tissues of offspring revealed dysregulated DNA methylation and expression of those genes (e.g., Adcy3, Gnas, and Srebf1) were reversed by maternal CR. Moreover, similar benefits of CR were observed in aberrant embryonic methylome of women with PCOS. These findings elucidate the essential role of CR in preventing PCOS transmission via methylation reprogramming, emphasizing the importance of preconception metabolic management for women with PCOS.

Association between imprinting disorders and assisted reproductive technologies

Aberrant expression of imprinted genes results in imprinting disorders (IDs). Differentially methylated regions (DMRs) reveal parental-origin-specific DNA methylation on CpGs and regulate the expression of the imprinted genes. One etiology of IDs is epimutation (epi-IDs) induced by some error in the establishment or maintenance of methylation imprint during the processes of gametogenesis, fertilization, or early embryonic development. Therefore, it has been a concern that assisted reproductive technologies (ART) increase the risk for the development of IDs, particularly epi-IDs. We review the effects of ART on DNA methylation of the genome, including DMRs in gametes, embryos, and offspring, and the risk of advanced parental age (a confounding factor of ART) and infertility itself for the development of IDs, particularly epi-IDs.

β-Diketone Functionalized Microspheres Chelate Reactive Iron via Metal Coordination for Cartilage Repair

Excessive intracellular iron accumulation can induce mitochondrial dysfunction, leading to chondrocyte ferroptosis, a key contributor to cartilage damage in osteoarthritis (OA). Here, micelle-microfluidic hydrogel microspheres, featuring keto-enol-thiol bridged nano-sized secondary structures that disintegrate within the intracellular peroxidative environment to reveal β-diketone groups with metal chelation capabilities, are utilized for the in situ removal of reactive iron, thereby facilitating cartilage repair through the restoration of mitochondrial homeostasis. The relevant experiments demonstrate that the microspheres reduce iron influx by downregulating transferrin receptor (TfR1) expression and decrease mitochondrial iron uptake by upregulating mitochondrial outer membrane iron-sulfur cluster protein (CISD1), thus restoring intracellular mitochondrial iron homeostasis. Furthermore, the antioxidant properties of the ketone-thioether segments synergistically mitigate chondrocyte phospholipid peroxidation via Nrf2/SLC7A11/GPX4 axis, inhibiting ferroptosis and slowing OA progression. In summary, this system that in situ sustainably chelates reactive iron via metal coordination exhibits great potential in the minimally invasive treatment of OA and other ferroptosis-mediated diseases.

Effects of Gonadotropin-Releasing Hormone Analogues on Ovarian Function and Embryogenesis: A Cyclophosphamide-Induced Mouse Model Study

OBJECTIVE

To clarify the protective effects of gonadotropin-releasing hormone analogues (GnRHas) on cyclophosphamide (CTX)-induced oocyte number loss and development of potential damage.

DESIGN

Mice model study.

SETTING

Laboratory-based animal study conducted in controlled research facilities.

POPULATION

Female C57/BL6 mice subjected to CTX-induced ovarian damage.

METHODS

The effects of GnRHa on CTX mice were evaluated in terms of hormones, oocyte count on slices, oocyte count in established three-dimensional-constructed ovaries, in vitro fertilisation, RNA sequencing and microinjection.

MAIN OUTCOME MEASURES

The main outcome measures were the number of oocytes in intact mouse ovaries and oocyte quality, evaluated using three-dimensional (3D) tissue-clearing methods, oxidative stress markers (reactive oxygen species [ROS] and malondialdehyde [MDT]), mitochondrial function (ATP levels), and embryogenesis rates at the two-cell, four-cell and blastocyst stages.

RESULTS

In CTX mice, GnRHa pretreatment did not protect endocrine hormone changes, but protected loss of oocyte number on slice counting. A tissue-clearing technique, CUBIC (Clear, Unobstructed Body Imaging Cocktails), was a suitable method for ovaries clearing, and a 3D method for oocyte counting was validated with accuracy of 105.22% ± 3.48%. By this method, GnRHa was also found to protect the loss of oocyte number (597 ± 28 vs. 222 ± 15, p < 0.0001), which may be mediated by upregulated anti-Müllerian hormone (AMH) levels inhibiting primordial follicle development approved by in vitro culture of ovaries. GnRHa also increased the number of retrieved oocytes in CTX mice (19.4 ± 2.1 vs. 15.0 ± 1.6, p < 0.0001) and developmental ability of oocytes (65.0 ± 4.6 vs. 48.1 ± 4.2 for blastocyst, p < 0.0001). RNA sequencing revealed GnRHa pretreatment downregulated pathways of exogenous drug metabolism, oxidative stress and cytochrome P450, validated by detection of adenosine triphosphate (ATP), MDA and ROS levels. The up-expression of Cox17 (cytochrome c oxidase copper chaperone 17) after GnRHa pretreatment was confirmed by PCR and microinjection of siCox17 increased the embryogenesis from CTX mice.

CONCLUSIONS

GnRHa was associated with reduced oocyte loss and improved embryogenesis, likely mediated by AMH and Cox17 upregulation.

High-Fat Diet and Altered Radiation Response

High-fat diets (HFDs) have become increasingly prevalent in modern societies, driving rising rates of obesity and metabolic syndrome. Concurrently, radiation exposure from medical treatments and environmental sources poses health risks shaped by both biological and environmental factors. This review explores the intersection between HFDs and radiation sensitivity/susceptibility, focusing on how diet-induced metabolic alterations influence the body's response to radiation. Evidence from preclinical and clinical studies indicates that HFDs significantly alter metabolism, leading to increased oxidative stress and immune system dysregulation. These metabolic changes can exacerbate radiation-induced oxidative stress, inflammation, and DNA damage, potentially increasing radiation sensitivity in normal tissues. Conversely, obesity and HFD-induced metabolic disruptions may activate cellular pathways involved in DNA repair, cell survival, and inflammatory responses, fostering tumor resistance and modifying the tumor microenvironment, which may impair the efficacy of radiation therapy in cancer treatment. Understanding the interplay between diet and radiation exposure is critical for optimizing public health guidelines and improving therapeutic outcomes. These findings underscore the need for further research into dietary interventions that may mitigate radiation-associated risks.

Genetic and reproductive strategies to prevent mitochondrial diseases

Mitochondrial DNA (mtDNA) diseases pose unique challenges for genetic counselling and require tailored approaches to address recurrence risks and reproductive options. The intricate dynamics of mtDNA segregation and heteroplasmy shift significantly impact the chances of having affected children. In addition to natural pregnancy, oocyte donation, and adoption, IVF-based approaches can reduce the risk of disease transmission. Prenatal diagnosis (PND) and preimplantation genetic testing (PGT) remain the standard methods for women carrying pathogenic mtDNA mutations; nevertheless, they are not suitable for every patient. Germline nuclear transfer (NT) has emerged as a novel therapeutic strategy, while mitochondrial gene editing has increasingly become a promising research area in the field. However, challenges and safety concerns associated with all these techniques remain, highlighting the need for long-term follow-up studies, an improved understanding of disease mechanisms, and personalized approaches to diagnosis and treatment. Given the inherent risks of adverse maternal and child outcomes, careful consideration of the balance between potential benefits and drawbacks is also warranted. This review will provide critical insights, identify knowledge gaps, and underscore the importance of advancing mitochondrial disease research in reproductive health.

High-dose estrogen impairs demethylation of H3K27me3 by decreasing Kdm6b expression during ovarian hyperstimulation in mice

Given that ovarian stimulation is vital for assisted reproductive technology (ART) and results in elevated serum estrogen levels, exploring the impact of elevated estrogen exposure on oocytes and embryos is necessary. We investigated the effects of various ovarian stimulation treatments on oocyte and embryo morphology and gene expression using a mouse model and estrogen-treated mouse embryonic stem cells (mESCs). Female C57BL/6J mice were subjected to two types of conventional ovarian stimulation and ovarian hyperstimulation; mice treated with only normal saline served as controls. Hyperstimulation resulted in high serum estrogen levels, enlarged ovaries, an increased number of aberrant oocytes, and decreased embryo formation. The messenger RNA (mRNA)‍-sequencing of oocytes revealed the dysregulated expression of lysine-specific demethylase 6b (Kdm6b), which may be a key factor indicating hyperstimulation-induced aberrant oocytes and embryos. In vitro, Kdm6b expression was downregulated in mESCs treated with high-dose estrogen; treatment with an estrogen receptor antagonist could reverse this downregulated expression level. Furthermore, treatment with high-dose estrogen resulted in the upregulated expression of histone H3 lysine 27 trimethylation (H3K27me3) and phosphorylated H2A histone family member X (γ-H2AX). Notably, knockdown of Kdm6b and high estrogen levels hindered the formation of embryoid bodies, with a concomitant increase in the expression of H3K27me3 and γ-H2AX. Collectively, our findings revealed that hyperstimulation-induced high-dose estrogen could impair the demethylation of H3K27me3 by reducing Kdm6b expression. Accordingly, Kdm6b could be a promising marker for clinically predicting ART outcomes in patients with ovarian hyperstimulation syndrome.

Association of maternal metabolic risk factors with offspring body mass index (BMI) trajectories in early childhood: a retrospective cohort study

OBJECTIVE

This study aimed to identify body mass index (BMI) growth trajectories from birth to 24 months of age and examine the independent and additive effects of four maternal metabolic risk factors, namely prepregnancy BMI, the rate of gestational weight gain, gestational diabetes mellitus (GDM) and gestational hypertension, on offspring growth trajectories in childhood in China.

DESIGN

A retrospective cohort study was conducted.

SETTING

The study used Maternal and Child Health Management Database in Chengdu, China, including the mothers' antenatal care data, birth certificate records and 0-3-year-old children's healthcare data.

PARTICIPANTS

The study included mothers who gave birth between January 2014 and December 2014, and followed their offspring through 31 December 2016. The final analysis included 4492 mother-child pairs.

PRIMARY OUTCOME MEASURES

The primary outcomes were children's BMI measurements from birth to 24 months of age. We performed group-based trajectories modelling to identify children's BMI growth trajectories. Then, we applied logistic regression to examine the associations between maternal metabolic risk factors and offspring BMI trajectories in childhood.

RESULTS

Four distinct trajectories were identified: stable low (16.83%), stable average (40.69%), stable high (32.06%) and early increase (10.42%) trajectories. Relative to the stable average trajectory, maternal prepregnancy overweight (adjusted OR (aOR)=2.001, 95% CI 1.482-2.702, p<0.001), an excessive rate of gestational weight gain (aOR=1.496, 95% CI 1.138-1.966, p=0.004) and GDM (aOR=1.470, 95% CI 1.097-1.970, p=0.010) were positively associated with their offspring being in the early increase trajectory. In addition, the children's risk of being included in the early increase trajectory showed an increasing trend with an increasing number of adverse maternal metabolic risk factors.

CONCLUSION

Exposure to maternal prepregnancy overweight, excessive rate of weight gain and GDM resulted in a greater risk of offspring exhibiting an early increase trajectory for BMI. Decreasing maternal metabolic risk before and during pregnancy and monitoring childhood growth trajectories may prevent or delay the onset of childhood obesity.

Maternal exposure to nicotine causes oxidative stress and inflammatory changes in the ovaries of rats' adult offspring

Nicotine is one of the most toxic substances found in cigarettes, but also found in chewing tobacco gum, patches and vaping products (electronic cigarettes). In addition to being a highly addictive chemical, it is capable of reducing fertility in men and women. In the ovaries, it can induce morphological changes and impair the formation of follicles, being a possible cause of changes in the reproductive cycle and anticipation of menopause in women whose mothers smoked during pregnancy. By increasing the generation of free radicals, nicotine can induce oxidation in biological samples and change the expression of inflammatory cytokines. It damages the immune system and many other cells of newborns exposed prenatally. Despite its teratogenic potential, many women continue to use this drug during pregnancy and lactation. Thus, this work aims to analyze the effects of maternal exposure to nicotine on the ovaries of adult rats. To this end, 10 rats received nicotine throughout pregnancy and lactation. Their offspring were euthanized around 90 days-old, in the metestrus phase, for ovary collection and analysis of oxidative stress and inflammation. The results showed that exposure to nicotine increased MDA level, but did not cause damage to the DNA of ovarian cells (8-OHdG). It also increased IL-1β and anti-inflammatory protein AnxA1 and receptor Fpr1, and reduced the mast cell population in ovaries. We concluded that maternal exposure to nicotine is capable of inducing oxidative stress and leading to inflammatory changes in the ovaries of adult offspring exposed during the intrauterine and breastfeeding phases.

Poldip2 promotes mtDNA elimination during Drosophila spermatogenesis to ensure maternal inheritance

Maternal inheritance of mitochondrial DNA (mtDNA) is highly conserved in metazoans. While many species eliminate paternal mtDNA during late sperm development to foster maternal inheritance, the regulatory mechanisms governing this process remain elusive. Through a forward genetic screen in Drosophila, we identified 47 mutant lines exhibiting substantial retention of mtDNA in mature sperm. We mapped one line to poldip2, a gene predominantly expressed in the testis. Disruption of poldip2 led to substantial mtDNA retention in mature sperm and subsequent paternal transmission to progeny. Further investigation via imaging, biochemical analyses and ChIP assays revealed that Poldip2 is a mitochondrial matrix protein capable of binding mtDNA. Moreover, we showed that ClpX, the key component of a major mitochondrial protease, interacts with Poldip2 to co-regulate mtDNA elimination in Drosophila spermatids. This study sheds light on the mechanisms underlying mtDNA removal during spermatogenesis and underscores the pivotal role of this process in safeguarding maternal inheritance.

Antimicrobial potential of the leaves of Citrus grandis (L.) Osbeck collected from Iraq: Bioassay-guided isolation of sinensetin as the anti-MRSA compound

Infections caused by antibiotic-drug-resistant microorganisms are a major global health concern, and they result in millions of deaths every year. Methicillin-resistant Staphylococcus aureus (MRSA) is one of such drug-resistant microbial strains, and new and effective antimicrobial agents are desperately needed to combat infections caused by MRSA. In the search for effective anti-MRSA agents, the leaves of Citrus grandis (Rutaceae), also known as C. maxima, were investigated. Implementing a bioassay-guided approach, sinensetin (2), which is a polymethoxyflavone, was isolated as a promising anti-MRSA compound, showing inhibitory activity against three (EMRSA-15, MRSA340802 and MRSA274819; MIC values 128-256 μg/mL) of five MRSA strains tested in the present study. Five other flavonoids 6,7,8,3',4'-pentamethoxyflavone (1), cirsilineol (3), nobiletin (4), 5-desmethylsinensetin (5) and hesperidin (6) were isolated from the dichloromethane extract of this plant. They displayed varied levels of antimicrobial activities against the tested microbial strains, Micrococcus luteus NCTC 7508, Escherichia coli NCTC 12241 and Pseudomonas aeruginosa NCTC 12903, and a fungal strain, Candida albicans ATCC 90028, but not against Staphylococcus aureus NCTC 12981. Sinensetin (2) also exhibited strong antimicrobial activity against the fungal strain C. albicans with an MIC value of 0.0625 mg/mL. The chemical structures of all isolated compounds were unequivocally elucidated by spectroscopic means (1D and 2D NMR and HR-ESIMS). The present study revealed sinensetin (2) as a potential structural template for generating structural analogues and developing anti-MRSA agents and provided scientific evidence supporting the traditional uses of C. grandis in the treatment of microbial infections.

Sperm mtDNA Copy Number Is Not Associated With Midpiece Size Among Songbirds

Tremendous variation in sperm morphology is observed across the animal kingdom. Within avian taxa, the songbirds (infraorder Passerides) have the largest variation in sperm morphology. Their spermatozoa move by using energy generated in the midpiece, which is formed by multiple mitochondria fusing together during spermatogenesis. However, very little is known regarding the number of mitochondria required to form the songbird midpiece. Based on previous research showing an association of midpiece length and mitochondrial DNA (mtDNA) copy number in the zebra finch Taeniopygia guttata, we hypothesize that songbird species with longer sperm midpieces have more copies of mtDNA. We estimated the sperm mtDNA copy number in 19 species from 10 families within Passerides, covering a broad range of midpiece sizes. Mitochondrial and nuclear DNA abundance were determined using droplet digital PCR (ddPCR) and the ratio between mitochondrial and single-copy nuclear genes was used to estimate mtDNA copy number per spermatozoon. We found that species differ in their average mtDNA copy number, but the variation was small and not significantly related to midpiece length. A possible explanation is that mitochondrial genomes are eliminated in the spermatids during spermatogenesis.

Mitochondrial DNA removal is essential for sperm development and activity

Active mitochondrial DNA (mtDNA) elimination during spermatogenesis has emerged as a conserved mechanism ensuring the uniparental mitochondrial inheritance in animals. However, given the existence of post-fertilization processes degrading sperm mitochondria, the physiological significance of mtDNA removal during spermatogenesis is not clear. Here we show that mtDNA clearance is indispensable for sperm development and activity. We uncover a previously unappreciated role of Poldip2 as a mitochondrial exonuclease that is specifically expressed in late spermatogenesis and required for sperm mtDNA elimination in Drosophila. Loss of Poldip2 impairs mtDNA clearance in elongated spermatids and impedes the progression of individualization complexes that strip away cytoplasmic materials and organelles. Over time, poldip2 mutant sperm exhibit marked nuclear genome fragmentation, and the flies become completely sterile. Notably, these phenotypes were rescued by expressing a mitochondrially targeted bacterial exonuclease, which ectopically removes mtDNA. Our work illustrates the developmental necessity of mtDNA clearance for effective cytoplasm removal at the end of spermatid morphogenesis, and for preventing potential nuclear-mitochondrial genome imbalance in mature sperm, in which nuclear genome activity is shut down.

Mitochondrial content and mtDNA copy number in spermatozoa and penetrability into oocytes

The current narrative review aims to summarize the relation of mitochondrial content (MC) and mitochondrial DNA copy number (MDCN) in spermatozoa with sperm penetrability, and to discuss the various determining factors during the process of spermatogenesis in mammals. There are many potential factors associated with the quantitative alteration of MC and MDCN in male gametes from spermatogenesis to ejaculation. Particularly, spermatogenesis may be the first step to jointly contribute to an incomplete reduction of MC and MDCN in spermatozoon. It appears to be now quite clear that some abnormalities during spermatogenesis and oxidative stress are the main factors highly associated with the quantitative change of MC and MDCN in spermatozoa, consequently affecting sperm quality and their penetrability into oocytes. Currently, a series of proteins contributing to form sperm midpiece during spermatogenesis and cytoplasmic elimination during spermiation have been currently identified. The present review provides insight into how these factors interact with sperm MC and MDCN, and handholds to gain a better understanding of their roles. This review also highlights the uniqueness of normal fertile spermatozoa which have relatively lower MC and MDCN, but have mitochondria that function completely in multiple pivotal physiological pathways.

Smooth endoplasmic reticulum aggregates in human oocytes are related to female infertility etiology and diminished reproductive outcomes

Smooth endoplasmic reticulum aggregates (SERa) are a type of dysmorphism in oocytes derived from controlled ovarian stimulation (COS). The effect of SERa on assisted reproductive techniques (ART) outcomes is debatable. Based on some evidence, SERa-positive (SERa+) oocytes cause complications including newborn demise, and compromise the outcome of the unaffected oocytes of the same cycle. While other reports demonstrated equal developmental competence between SERa + and SERa-negative (SERa-) oocytes/cycles. We conducted a prospective cross-sectional study on 315 women candidates for ART and compared the outcome among SERa+ (N = 73) and SERa- cycles (N = 217). Furthermore, for the first time, we investigated the prevalence of SERa + cycles in women with various infertility etiologies. Our results indicated that SERa + patients presented higher levels of Estradiol on the day of ovulation triggering (p = 0.02). Regarding the ART outcome, there were no differences in the number of retrieved oocytes, oocyte maturation and fertilization rates among the groups. However, the quality of the unaffected oocytes (p = 0.03), the rates of day-3 top-quality embryos (p = 0.01, and p = 0.03 for grades A and B, respectively), and clinical pregnancy (p = 0.05) in SERa + group were significantly reduced. Moreover, the prevalence of SERa + cycles gradually increased among endometriosis, POI/POR, PCOS, normal women, tubal factor, and idiopathic groups. Our study suggests that suboptimal situations such as elevated levels of Estradiol can increase the occurrence of SERa + oocytes. This suboptimal phenomenon can negatively influence the outcome of the cycle. Thus, optimization of COS, particularly in vulnerable groups such as women with idiopathic infertility may lower the SERa + cycle occurrence, improving the ART outcome.

Effects and Mechanisms of Imperatorin on Vitrified Mouse Oocytes

Imperatorin (IMP) is a naturally occurring furanocoumarin with beneficial biological activities such as anticancer, antioxidant, and neuromodulatory properties. Currently, the protective effects and mechanisms of IMP on oxidative stress experienced by mouse oocytes after vitrification-thawing remain unclear. To investigate the influence of IMP on mouse oocyte development after vitrification-thawing, we added different concentrations of IMP to the vitrification and thawing media. Results indicated that the addition of 40 μM IMP enhanced post-thaw fertilization capacity, reduced intracellular reactive oxygen species (ROS) levels, and increased intracellular glutathione (GSH) levels. IMP also improved mitochondrial health by alleviating the decrease in mitochondrial membrane potential (MMP) and enhancing mitochondrial distribution. IMP reduced intracellular ROS levels by affecting the transcription of the antioxidant genes SOD2, NRF2, and HO-1 and enhancing SOD activity. It also elevated GSH levels via GPX1, improved mitochondrial function, and decreased early apoptosis through Bcl-2. In conclusion, IMP enhanced ovum health through the alleviation of oxidative stress. The present study provides useful information for further exploration of the molecular mechanisms of IMP in female reproductive cells and offers a novel approach for the improvement of vitrification technology.

Herbicide-related health risks: key mechanisms and a guide to mitigation strategies

BACKGROUND

Herbicides are a group of substances used to control undesired vegetation in both agricultural and non-agricultural settings. They are recorded as the most consumed class among other pesticides, reaching nearly two million tons worldwide. Despite their effectiveness in weed control, the extensive utilization of herbicides has raised concerns regarding adverse effects on human health. However, comprehensive reviews addressing herbicide-related human health risks remain limited. This work aims to compile scientific evidence and possible underlying mechanisms to emphasize the hazards that need to be acknowledged, as well as to explore novel strategies for minimizing the impact on human health.

METHOD

Scientific data on herbicide-related human health risks, including human-related data and non-human experimental research, were retrieved from databases such as PubMed, Scopus, and Google Scholar. Pre-determined eligibility criteria were applied to select the final studies.

RESULT

A narrative summary of evidence-based human incidence and laboratory experiments is presented to organize and highlight key findings. This indicates the life-threatening nature of herbicide exposure in humans, ranging from acute toxicity to the development of chronic diseases at any stage of life.

CONCLUSION

Herbicidal chemicals can harm individuals through various pathways, especially by inducing oxidative stress or directly disrupting molecular and cellular processes. Despite some conflicting findings, effective mitigation strategies are urgently needed to promote a safer society and protect human well-being.

The Mammalian Oocyte: A Central Hub for Cellular Reprogramming and Stemness

The mammalian oocyte is pivotal in reproductive biology, acting as a central hub for cellular reprogramming and stemness. It uniquely contributes half of the zygotic nuclear genome and the entirety of the mitochondrial genome, ensuring individual development and health. Oocyte-mediated reprogramming, exemplified by nuclear transfer, resets somatic cell identity to achieve pluripotency and has transformative potential in regenerative medicine. This process is critical for understanding cellular differentiation, improving assisted reproductive technologies, and advancing cloning and stem cell research. During fertilization, the maternal-zygotic transition shifts developmental control from maternal factors to zygotic genome activation, establishing totipotency. Oocytes also harbor reprogramming factors that guide nuclear remodeling, epigenetic modifications, and metabolic reprogramming, enabling early embryogenesis. Structures like mitochondria, lipid droplets, and cytoplasmic lattices contribute to energy production, molecular regulation, and cellular organization. Recent insights into oocyte components, such as ooplasmic nanovesicles and endolysosomal vesicular assemblies (ELVAS), highlight their roles in maintaining cellular homeostasis, protein synthesis, and reprogramming efficiency. By unraveling the reprogramming mechanisms inherent in oocytes, we advance our understanding of cloning, cell differentiation, and stem cell therapy, highlighting their valuable significance in developmental biology and regenerative medicine.

PAK4 promotes the cytoskeletal organization and meiotic maturation via phosphorylating DDX17 in oocyte

PAK4 has been widely reported to function in somatic cells. However, its role and the underlying mechanisms in meiotic oocytes are largely unknown. Here, we show that PAK4 deficiency significantly disrupts maturational progression and meiotic apparatus in mouse oocytes. Furthermore, based on the kinase substrate binding preference and systematic functional screening, our mechanistic investigation demonstrated that PAK4 promotes cytoskeletal organization and oocyte maturation through phosphorylating serine 597 on DDX17. Of note, we identified a marked reduction of PAK4 protein in oocytes from diabetic mice. Importantly, ectopic expression of hyperphosphorylation-mimicking DDX17 mutant (DDX17-S597D) partly prevented the meiotic defects in these diabetic oocytes, indicating that the decreased phosphorylation of DDX17 due to PAK4 insufficiency is responsible for the impaired oocyte quality. In sum, these findings unveil the pivotal role of PAK4 in oocyte development and indicate a novel mechanism controlling meiotic progression and structure.

CDK1 mediates the metabolic regulation of DNA double-strand break repair in metaphase II oocytes

BACKGROUND

During oocyte maturation, DNA double-strand breaks (DSBs) can decrease oocyte quality or cause mutations. How DSBs are repaired in dividing oocytes and which factors influence DSB repair are not well understood.

RESULTS

By analyzing DSB repair pathways in oocytes at different stages, we found that break-induced replication (BIR) and RAD51-mediated homology-directed repair (HDR) were highly active in germinal vesicle breakdown (GVBD) oocytes but suppressed in metaphase II (MII) oocytes and the BIR in oocytes was promoted by CDK1 activity. By culturing oocytes in different media, we found that high-energy media, such as DMEM, decreased CDK1 protein levels and suppressed BIR or HDR in MII oocytes. In contrast, 53BP1-mediated nonhomologous end joining (NHEJ) repair was inhibited in germinal vesicle (GV) and GVBD oocytes but promoted in MII oocytes, and NHEJ was not affected by DMEM medium and CDK1 activity. In addition, in DSB MII oocytes, polymerase theta-mediated end joining (TMEJ) was found to be suppressed by CDK1 activity and promoted by high-energy media.

CONCLUSIONS

In summary, MII oocytes exhibit high heterogeneity in DSB repair, which is regulated by both metabolic factors and CDK1 activity. These results not only expand our understanding of oocyte DSB repair but also contribute to the modification of in vitro maturation medium for oocytes.

Sperm epigenetics and sperm RNAs as drivers of male infertility: truth or myth?

Male infertility represents a complex clinical condition that often challenges the ability of reproductive specialists to find its etiology and then propose an adequate treatment. The unexplained decline in sperm count, as well as the association between male infertility and mortality, morbidity, and cancer, has prompted researchers toward an urgent need to better understand the causes of male infertility. Therefore, molecular biologists are increasingly trying to study whether sperm epigenetic alterations may be involved in male infertility and embryo developmental abnormalities. In this context, research is also trying to uncover the hidden role of sperm RNAs, both coding and non-coding. This narrative review aims to thoroughly and comprehensively present the relationship between sperm epigenetics, sperm RNAs, and human fertility. We first focused on the technological aspects of studying sperm epigenetics and RNAs, relating to the complex role(s) played in sperm maturation, fertilization, and embryo development. Then, we examined the intricate connections between epigenetics and RNAs with fertility measures, namely sperm concentration, embryo growth and development, and live birth rate, in both animal and human studies. A better understanding of the molecular mechanisms involved in sperm epigenetic regulation, as well as the impact of RNA players, will help to tackle infertility.

Role of epigenetic regulation in diminished ovarian reserve

Diminished ovarian reserve (DOR) is characterized by a decrease in the number and quality of oocytes, with its incidence increasing annually. Its pathogenesis remains unclear, making it one of the most challenging problems in the field of assisted reproduction. Epigenetic modification, a molecular mechanism affecting genomic activity and expression without altering the DNA sequence, has been widely studied in reproductive medicine and has attracted considerable attention regarding DOR. This review comprehensively examines the various epigenetic regulatory changes in ovarian granulosa cells (OGCs) and oocytes during DOR. DNA methylation plays a crucial role in regulating granulosa cell function, hormone production, and oocyte development, maturation, and senescence. Histone modifications are involved in regulating follicular activation, while non-coding RNAs, such as long noncoding RNAs (lncRNAs) and microRNAs (miRNAs), regulate granulosa cell function and oocyte development. N6-methyladenosine (m6A) modifications are associated with age-related oocyte senescence. Epigenetic clocks based on DNA methylation show potential in predicting ovarian reserve in DOR. Furthermore, it discusses the potential for utilizing epigenetic mechanisms to better diagnose and manage DOR.

Lipotoxicity and Oocyte Quality in Mammals: Pathogenesis, Consequences, and Reversibility

Metabolic stress conditions are often characterized by upregulated lipolysis and subsequently increased serum free fatty acid (FFA) concentrations, leading to the uptake of FFAs by non-adipose tissues and impairment of their function. This phenomenon is known as lipotoxicity. The increased serum FFA concentrations are reflected in the ovarian follicular fluid, which can have harmful effects on oocyte development. Several studies using in vitro and in vivo mammalian models showed that altered oocyte metabolism, increased oxidative stress, and mitochondrial dysfunction are crucial mechanisms underlying this detrimental impact. Ultimately, this can impair offspring health through the persistence of defective mitochondria in the embryo, hampering epigenetic reprogramming and early development. In vitro and in vivo treatments to enhance oocyte mitochondrial function are increasingly being developed. This can help to improve pregnancy rates and safeguard offspring health in metabolically compromised individuals.

Letrozole Cotreatment Reduces Unexpectedly Poor Responses in Ovarian Stimulation With Follitropin Delta: A Strategy to Prevent High Anti-Müllerian Hormone (AMH) but Poor Response

BACKGROUND

Follitropin delta is a novel recombinant follicle-stimulating hormone preparation used for in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). The dosage is determined using an original algorithm designed to achieve a target retrieval of 8-14 oocytes based on body weight and anti-Müllerian hormone (AMH) levels. However, unexpected poor responses, characterized by low oocyte retrieval numbers, occasionally occur in patients with high AMH levels who are otherwise expected to respond well. This study investigated whether cotreatment with letrozole reduces such poor responses.

METHODS

A retrospective cohort study including 153 controlled ovarian stimulation (COS) cycles for IVF/ICSI using follitropin delta was performed at Haruki Ladies Clinic in Japan from October 2021 to March 2023. In total, 42 cycles were performed in the letrozole cotreatment group, and 111 cycles were performed in the group treated with follitropin delta alone. According to the concept of follitropin delta, seven or fewer oocytes retrieved were defined as a poor response.

RESULTS

An unexpectedly poor response was observed at 6.0-6.9 µg daily doses of follitropin delta. The poor response was less frequent in the cotreatment group: one of 36 cycles (2.8%) in the cotreatment group and nine of 49 cycles (18.4%) in the follitropin delta alone group (p < 0.05). At daily doses of 7.0-11.9 μg, poor response was not often observed in both groups (0% vs. 3.6%). At 12.0 μg of daily dose, poor response frequently occurred in both groups. The duration of ovarian stimulation was decreased by cotreatment with letrozole (10.4 days vs. 8.7 days, p < 0.01). Letrozole cotreatment also reduced the total dosage of follitropin delta (65.2 µg vs. 53.3 µg, p < 0.01).

CONCLUSIONS

Cotreatment with letrozole may reduce unanticipated suboptimal responses in patients expected to have good responses. Additionally, it may shorten the duration of ovarian stimulation and decrease the total dosage of follitropin delta required.

Asymmetric partitioning of persistent paternal mitochondria during cell divisions safeguards embryo development and mitochondrial inheritance

Most eukaryotes inherit only maternal mitochondria. The reasons for paternal mitochondrial elimination and the impacts of persistent paternal mitochondria on animals remain elusive. We show that undegraded paternal mitochondria in autophagy-deficient C. elegans embryos are gradually excluded from germ blastomeres through asymmetric partitioning during cell divisions. The embryonic cortical flow drives anterior-directed movements of paternal mitochondria and contributes to their asymmetric apportioning between two daughter blastomeres. By contrast, autophagosome-enclosed paternal mitochondria cluster around and segregate with centrosomes during mitosis and are rapidly degraded through lysosomes concentrated near centrosomes. Failure to exclude persistent paternal mitochondria from the germ blastomere at first cleavage causes their enrichment in the descendant endomesodermal (EMS) blastomere, leading to elevated reactive oxygen species levels, elongated EMS lineage durations, and increased embryonic lethality, which antioxidant treatments can suppress. Thus, regulated paternal mitochondrial distribution away from germ blastomeres is a fail-safe mechanism, protecting embryo development and maternal mitochondrial inheritance.

Role of spindle assembly checkpoint proteins in gametogenesis and embryogenesis

The spindle assembly checkpoint (SAC) is a surveillance mechanism that prevents uneven segregation of sister chromatids between daughter cells during anaphase. This essential regulatory checkpoint prevents aneuploidy which can lead to various congenital defects observed in newborns. Many studies have been carried out to elucidate the role of proteins involved in the SAC as well as the function of the checkpoint during gametogenesis and embryogenesis. In this review, we discuss the role of SAC proteins in regulating both meiotic and mitotic cell division along with several factors that influence the SAC strength in various species. Finally, we outline the role of SAC proteins and the consequences of their absence or insufficiency on proper gametogenesis and embryogenesis in vivo.

[Mechanisms of Wandai Decoction in Improving Vaginal Flora of Vulvovaginal Candidiasis of the Spleen Deficiency and Excessive Dampness Type: A Study Based on Metagenomics and Metabolomics]

Objective

To explore the mechanism by which Wandai Decoction prevents and treats vulvovaginal candidiasis (VVC) of the spleen deficiency and excessive dampness type and restores the vaginal flora structure, and to identify the potential metabolic pathways involved using metagenomics and metabolomics.

Methods

Twenty VVC patients who met the inclusion criteria were randomly assigned to a Wandai Decoction group and a fluconazole group (n = 10 in each group). Subjects in the fluconazole group were given a single oral dose of 150 mg fluconazole, while those in the Wandai Decoction group took the Wandai Decoction orally for 14 days. The vulvovaginal signs and symptoms (VSS) scores of both patient groups were evaluated before and after treatment. Vaginal secretions were collected before and after treatment. The Illumina sequencing and the liquid chromatography with tandem mass spectrometry (LC-MS/MS) platform were used to conduct metagenomic and metabolomics analyses of the vaginal secretions, respectively.

Results

The VSS score results showed that the VSS scores of both groups decreased after treatment compared with those before treatment (P < 0.01), and there was no statistically significant difference in the VSS scores between the two groups after treatment. Metagenomics results showed that, after treatment, the vaginal microbial communities in the Wandai Decoction group were of CST Ⅱ and Ⅴ types (predominated by Lactobacillus gasseri and Lactobacillus jensenii), while those in the fluconazole group were Lactobacillus_intestinalis and Streptococcus_sp._oral_ taxon_431. KEGG functional enrichment analysis results showed that, in terms of the cell cycle and meiosis functions of Candida albicans, statistically significant differences between the Wandai Decoction and fluconazole groups were observed (P < 0.05). Metabolomic analysis identified 120 differential metabolites between the two groups after treatment. The results of KEGG metabolic pathway enrichment analysis of differential metabolites showed that the Wandai Decoction might be significantly superior to fluconazole in improving local vaginal metabolic pathways of α-linolenic acid, glycerophospholipid metabolism, pentose and glucuronic acid interconversion, and arachidonic acid.

Conclusion

The Wandai Decoction can improve the vaginal flora of VVC patients. It may be superior to fluconazole in the signaling pathways of the cell cycle and meiosis. The improvement of the vaginal flora by the Wandai Decoction may be associated with its effect on metabolic pathways of glycerophospholipid metabolism, pentose and glucuronic acid interconversion, and others in the vagina.

In vitro maturation of oocytes: what is already known?†

Assisted reproductive technologies (ARTs) involve the laboratory manipulation of gametes and embryos to help couples with fertility problems become pregnant. One of these procedures, controlled ovarian stimulation, uses pharmacological agents to induce ovarian and follicular maturation in vivo. Despite the effectiveness in achieving pregnancy and live births, some patients may have complications due to over-response to gonadotropins and develop ovarian hyperstimulation syndrome. In vitro maturation (IVM) of oocytes has emerged as a technique to reduce the risk of ovarian hyperstimulation syndrome, particularly in women with polycystic ovary syndrome, and for fertility preservation in women undergoing oncological treatment. Although there are some limitations, primarily due to oocyte quality, recent advances have improved pregnancy success rates and neonatal and infant outcomes. Different terms have been coined to describe variations of IVM, and the technique has evolved with the introduction of hormones to optimize results. In this review, we provide a comprehensive overview of IVM relating hormonal priming, culture system and media, and clinical indications for IVM with its reproductive outcomes during ARTs.

Extensive homologous recombination safeguards oocyte genome integrity in mammals

Meiosis in mammalian oocytes is interrupted by a prolonged arrest at the germinal vesicle stage, during which oocytes have to repair DNA lesions to ensure genome integrity or otherwise undergo apoptosis. The FIRRM/FLIP-FIGNL1 complex dissociates RAD51 from the joint DNA molecules in both homologous recombination (HR) and DNA replication. However, as a type of non-meiotic, non-replicative cells, whether this RAD51-dismantling mechanism regulates genome integrity in oocytes remains elusive. Here, we show that FIRRM/FLIP is required for disassembly of RAD51-filaments and maintenance of genome integrity in oocytes. Deletion of FIRRM in oocytes leads to formation of massive nuclear RAD51 foci in oocytes of primordial follicles and activated follicles in mice. These RAD51 foci colocalize with the sites of DNA damage repair, as indicated by RPA2 and EdU, suggesting substantial DNA damage and extensive HR in oocytes. Especially in fully-grown FIRRM-deleted oocytes, RAD51 forms a net-like structure. As a consequence, FIRRM-deleted females are infertile due to aberrant homologous chromosome segregation at metaphase I and primordial follicle insufficiency at young adulthood. Hence, our study demonstrates the physiological importance of HR in maintaining genome integrity in oocytes.

Mitochondrial diseases: from molecular mechanisms to therapeutic advances

Mitochondria are essential for cellular function and viability, serving as central hubs of metabolism and signaling. They possess various metabolic and quality control mechanisms crucial for maintaining normal cellular activities. Mitochondrial genetic disorders can arise from a wide range of mutations in either mitochondrial or nuclear DNA, which encode mitochondrial proteins or other contents. These genetic defects can lead to a breakdown of mitochondrial function and metabolism, such as the collapse of oxidative phosphorylation, one of the mitochondria's most critical functions. Mitochondrial diseases, a common group of genetic disorders, are characterized by significant phenotypic and genetic heterogeneity. Clinical symptoms can manifest in various systems and organs throughout the body, with differing degrees and forms of severity. The complexity of the relationship between mitochondria and mitochondrial diseases results in an inadequate understanding of the genotype-phenotype correlation of these diseases, historically making diagnosis and treatment challenging and often leading to unsatisfactory clinical outcomes. However, recent advancements in research and technology have significantly improved our understanding and management of these conditions. Clinical translations of mitochondria-related therapies are actively progressing. This review focuses on the physiological mechanisms of mitochondria, the pathogenesis of mitochondrial diseases, and potential diagnostic and therapeutic applications. Additionally, this review discusses future perspectives on mitochondrial genetic diseases.

Oxidative stress in diabetes mellitus and its complications: From pathophysiology to therapeutic strategies

ABSTRACT

Oxidative stress due to aberrant metabolism is considered as a crucial contributor to diabetes and its complications. Hyperglycemia and hyperlipemia boost excessive reactive oxygen species generation by elevated mitochondrial respiration, increased nicotinamide adenine dinucleotide phosphate oxidase activity, and enhanced pro-oxidative processes, including protein kinase C pathways, hexosamine, polyol, and advanced glycation endproducts, which exacerbate oxidative stress. Oxidative stress plays a significant role in the onset of diabetes and its associated complications by impairing insulin production, increasing insulin resistance, maintaining hyperglycemic memory, and inducing systemic inflammation. A more profound comprehension of the molecular processes that link oxidative stress to diabetes is crucial to new preventive and therapeutic strategies. Therefore, this review discusses the mechanisms underlying how oxidative stress contributes to diabetes mellitus and its complications. We also summarize the current approaches for prevention and treatment by targeting the oxidative stress pathways in diabetes.

Gestational diabetes mellitus causes genome hyper-methylation of oocyte via increased EZH2

Gestational diabetes mellitus (GDM), a common pregnancy disease, has long-term negative effects on offspring health. Epigenetic changes may have important contributions to that, but the underlying mechanisms are not well understood. Here, we report the influence of GDM on DNA methylation of offspring (GDF1) oocytes and the possible mechanisms. Our results show that GDM induces genomic hyper-methylation of offspring oocytes, and at least a part of the altered methylation is inherited by F2 oocytes, which may be a reason for the inheritance of metabolic disorders. We further find that GDM exposure increases the expression of Ezh2 in oocytes. Ezh2 regulates DNA methylation via DNMT1, and Ezh2 knockdown reduces the genomic methylation level of GDF1 oocytes. These results suggest that GDM may induce oocyte genomic hyper-methylation of offspring via enhancing the Ezh2 expression recruiting more DNMT1 into nucleus.

Selected plant extracts and female fertility: role in the regulation of the hypothalamo-pituitary-ovarian axis in normal and pathological conditions

Female infertility, which affects 10-20% of couples worldwide, is a growing health concern in developing countries. It can be caused by multiple factors, including reproductive disorders, hormonal dysfunctions, congenital malformations and infections. In vitro and in vivo studies have shown that plant extracts regulate gonadotropin-releasing hormone, kisspeptin, and gonadotropin expression and/or secretion at the hypothalamic-pituitary level and modulate somatic and germ cells, such as steroidogenesis, proliferation, apoptosis, and oxidative stress at the ovarian level. In this review, we report evidence for the role of certain plant extracts or plant bioactive compounds in the regulation of the hypothalamic-pituitary-ovary axis and, consequently, for the treatment of female infertility. We will also summarize their possible involvement in ovarian disorders such as polycystic ovary syndrome (PCOS), premature ovarian failure (POF) and ovarian cancers.

The quality of human eggs and its pre-IVF incubation

Background

Multi-factors influence the success rate of infertility treatments, and one of the important points is to obtain good quality eggs.

Methods

Based on the literatures and unpublished data, the factors affecting egg quality were summarized.

Main Findings Results

Egg quality is an important determinant in successful infertility treatment. In addition to maternal age, controlled ovarian hyperstimulation (COH) protocols also play a key role in affecting the quality of the egg. After egg retrieval, the insemination occurs 3-6 h after collection, with a pre-IVF incubation time by in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) (39-42 h post-HCG injection). The pre-IVF incubation refers to the short period time of 3 to 6 h after oocyte retrieval and before the insemination by IVF or ICSI. The pre-IVF incubation of collected eggs in the designed culture medium improves egg quality in terms of maturation and early embryonic development.

Conclusions

Pre-IVF incubation of the collected eggs contributes to the improvement of the quality of eggs; therefore, it may increase subsequent pregnancy and implantation rates following embryo transfer.

TFPI2 hypermethylation promotes diabetic atherosclerosis progression through the Ap2α/PPARγ axis

Diabetes mellitus significantly escalates the risk of accelerated atherosclerosis (AS), severely affecting cardiovascular health. Our research, leveraging Gene Expression Omnibus (GEO) database analysis (GSE118481), revealed diminished TFPI2 expression in diabetic patients' atherosclerotic plaques. Further validation in carotid artery plaques and an AS mouse model confirmed TFPI2's reduced expression in diabetes. Through TFPI2 knockdown in non-diabetic mice, we observed aggravated plaque burden and increased inflammatory M1 macrophage polarization. Conversely, TFPI2 overexpression in diabetic mice improved plaque stability and induced reparative M2 macrophage polarization, countering hyperglycemia's negative effects. Mechanistically, transcription factor activator protein 2α (AP-2α) is a repressor of PPPARg transcription, and the interaction of TFPI2 with the transcription factor AP-2α blocks AP-2α binding to the PPARγ gene promoter, which is essential for PPARγ-mediated transcription and the transition from M1 to M2 macrophages. Additionally, hyperglycemia-induced DNA methyltransferase 1 (DNMT1) upregulation heightens TFPI2 methylation, reducing its expression. Our findings spotlight the TFPI2/AP-2α/PPARγ axis as crucial in diabetic AS modulation, proposing its targeting as a new therapeutic strategy to halt diabetes-driven AS progression, highlighting TFPI2's therapeutic promise in addressing diabetes-related cardiovascular issues.