Epigenetic regulation in premature ovarian failure: A literature review

Nano-encapsulated senolytic cocktail attenuates germ cell senescence in female mice

Low-quality oocytes directly affect fertilization and embryonic development, contributing to infertility in women, while germ cell senescence leads to reduced germ cell numbers and decreased egg quality. Dasatinib and quercetin (D and Q), as senolytic drugs, have been extensively explored in different age-related diseases. However, their effects on in vitro cultured senescent oocytes and the molecular mechanisms underpinning ovarian aging remain elusive. Here, we report that a nano-encapsulated senolytic D + Q cocktail efficiently improves the quality of post-ovulatory aging oocyte in vitro and follicle quantity in ovaries in a cyclophosphamide (Cy)-induced premature ovarian failure (POF) mouse model. Cocktail supplementation to cultured oocytes potently reduces reactive oxygen species (ROS) levels, maintains spindle integrity, decreases fragmented oocyte frequencies, rescues mislocalized cortical granules (CGs) and mitochondrial membrane potential (MMP), and alleviates DNA damage and apoptosis. Importantly, the cocktail effectively ameliorates fertility deficits in the model. Transcriptome analysis shows cocktail administration to fertility-deficient mice not only up-regulates developmental gene expression but also reduces senescence-associated secretory phenotype (SASP) accumulation. Therefore, our nano-encapsulated D + Q cocktail is a promising reagent for assisted reproductive technology and improving reproductive outcomes in POF.

Epigenetic Alterations in Ovarian Function and Their Impact on Assisted Reproductive Technologies: A Systematic Review

Background: Epigenetic modifications have an important role in controlling ovarian function, modulating ovarian response and implantation success in Assisted Reproductive Technologies (ART). The alterations, such as DNA methylation and non-coding RNA control, have been identified as key variables regulating ovarian physiology and reproductive outcomes. This systematic review investigates the significance of epigenetic pathways in ovarian function, with an emphasis on their effect on ART success rates. Methods: A thorough search of the PubMed, Scopus, and EMBASE databases was performed to find articles published between 2015 and 2024 that investigated the connection between epigenetic changes and ovarian function in ART patients. Studies that examined miRNA expression, DNA methylation, and histone changes in follicular fluid, granulosa cells, and embryos were included. The study followed the PRISMA recommendations to guarantee scientific rigor and repeatability. The data were combined into a thorough study of epigenetic markers linked to ovarian aging, ovarian reserve, and implantation success. Results: A total of 15 studies satisfied the inclusion criteria, with substantial relationships found between distinct epigenetic markers and ovarian function. Changes in miRNA expression patterns in follicular fluid and granulosa cells were associated with oocyte maturation, ovarian reserve, and implantation potential. Women with low ovarian reserve and polycystic ovary syndrome (PCOS) have different DNA methylation patterns. MiR-27a-3p and miR-15a-5p were shown to be involved with granulosa cell malfunction and poor ovarian response, whereas global DNA hypomethylation was linked to ovarian aging and ART results. Conclusions: Epigenetic alterations affect ovarian function via pathways that control hormone signaling, follicular development, and implantation success. Further study is needed to determine the practical applicability of epigenetic biomarkers in predicting ART effectiveness and enhancing patient treatment procedures.

Epigenetic Landscapes of Aging in Breast Cancer Survivors: Unraveling the Impact of Therapeutic Interventions-A Scoping Review

Breast cancer therapies have dramatically improved survival rates, but their long-term effects, especially on aging survivors, need careful consideration. This review delves into how breast cancer treatments and aging intersect, focusing on the epigenetic changes triggered by chemotherapy, radiation, hormonal treatments, and targeted therapies. Treatments can speed up biological aging by altering DNA methylation, histone modifications, and chromatin remodeling, affecting gene expression without changing the DNA sequence itself. The review explains the double-edged sword effect of therapy-induced epigenetic modifications, which help fight cancer but also accelerate aging. Chemotherapy and targeted therapies, in particular, impact DNA methylation and histone modifications, promoting chronic inflammation and shortening telomeres. These changes increase biological age, as seen in epigenetic clocks and biomarkers like p21, which also play roles in drug resistance and therapeutic decisions. Chronic inflammation, driven by higher levels of inflammatory cytokines such as TNF-α and IL-6 as well as telomere shortening, significantly contributes to the aging characteristics of breast cancer survivors. Non-coding RNAs, including microRNAs and long non-coding RNAs, are crucial in regulating gene expression and aging pathways altered by these treatments. This review explores new therapies targeting these epigenetic changes, like DNA methylation inhibitors, histone deacetylase inhibitors, and microRNA-based treatments, to reduce the aging effects of cancer therapy. Non-drug approaches, such as dietary changes and lifestyle modifications, also show promise in combating therapy-induced aging. It also highlights the clinical signs of aging-related side effects, such as heart and lung problems, endocrine and reproductive issues, and reduced quality of life. The development of comprehensive methods like the CHEMO-RADIAT score to predict major cardiovascular events after therapy is discussed. Understanding the epigenetic changes caused by breast cancer therapies offers valuable insights for creating interventions to enhance the health span and quality of life for survivors. Continued research is crucial to fully understand these epigenetic alterations and their long-term health impacts.

Effect of ovarian reserve on pregnancy outcomes in patients undergoing IVF treatment due to azoospermia

PURPOSE

Infertility is an increasingly common condition that has demographic, psychological, economic, and medical consequences for society. Although many studies have examined azoospermia (AZO) and diminished ovarian reserve (DOR), few have investigated these two groups together. In this study, we aimed to contribute to the literature by comparing these conditions, which can be challenging for physicians and patients.

METHODS

The study included couples with AZO and/or DOR who underwent intracytoplasmic sperm injection (ICSI) at Tepecik Training and Research Hospital Gynecology and Obstetrics Clinic In Vitro Fertilization (IVF) Center between 01 January 2017 and 30 June 2023. A total of 100 couples meeting the inclusion criteria were divided into 3 groups according to treatment indication: AZO (n = 34), DOR (n = 34), and AZO + DOR (n = 32). The women's ages, basal hormone levels (follicle-stimulating hormone, estradiol, progesterone, anti-Müllerian hormone), treatment indications, day of embryo transfer, and clinical pregnancy outcomes were documented.

RESULTS

Clinical pregnancy rates were 64.7% in the AZO group, 50% in the DOR group, and 34.4% in the DOR + AZO group. In pairwise comparisons, the clinical pregnancy rate was significantly higher in the AZO group than in the DOR + AZO group (p = 0.014). The live birth rate was also significantly lower in the DOR + AZO group than in the AZO group (p = 0.022). In the DOR group, 70.6% of achieved pregnancies resulted in live birth and 29.4% in missed abortion.

CONCLUSION

Clinical pregnancy and live birth rates were found to be significantly higher in couples with AZO compared to those with both DOR and AZO. This suggests that the woman's ovarian reserve is more decisive than sperm quality in the success of IVF/ICSI.

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.

Epigenomic Landscape of Human Cumulus Cells in Premature Ovarian Insufficiency Using Single-Base Resolution Methylome and Hydroxymethylome

Premature ovarian insufficiency (POI) has recently been reported to be linked with epigenetic changes. Previous studies have focused on the regulation of individual genes associated with ovarian function through single-gene epigenetic variations; however, there is a deficiency in the comprehensive comprehension of the epigenetic profile for POI. Therefore, we conducted a multi-omics study integrating methylation, hydroxymethylation and transcriptome sequencing analyses in cumulus cells from women with POI and their matched controls. Our data revealed significant global increases in methylation and hydroxymethylation levels in POI patients. We observed a predominance of hypermethylated and hyperhydroxymethylated regions across the genome, with methylation in gene bodies negatively correlating with gene expression, especially in promoter regions. Subsequent experimental validation was performed to confirm the involvement of candidate genes (EGR1, EGR2 and DLX5) in ovarian steroid hormone synthesis. Interestingly, our findings indicate that these epigenetic modifications are associated with genes implicated in POI, ovarian function and the epigenetic age clock. This comprehensive epigenetic profile underscores the potential for identifying novel biomarkers and therapeutic targets for POI by unravelling the complex interplay between DNA epigenetics and ovarian function.

Mitochondria: the epigenetic regulators of ovarian aging and longevity

Ovarian aging is a major health concern for women. Ovarian aging is associated with reduced health span and longevity. Mitochondrial dysfunction is one of the hallmarks of ovarian aging. In addition to providing oocytes with optimal energy, the mitochondria provide a co-substrate that drives epigenetic processes. Studies show epigenetic alterations, both nuclear and mitochondrial contribute to ovarian aging. Both, nuclear and mitochondrial genomes cross-talk with each other, resulting in two ways orchestrated anterograde and retrograde response that involves epigenetic changes in nuclear and mitochondrial compartments. Epigenetic alterations causing changes in metabolism impact ovarian function. Key mitochondrial co-substrate includes acetyl CoA, NAD+, ATP, and α-KG. Thus, enhancing mitochondrial function in aging ovaries may preserve ovarian function and can lead to ovarian longevity and reproductive and better health outcomes in women. This article describes the role of mitochondria-led epigenetics involved in ovarian aging and discusses strategies to restore epigenetic reprogramming in oocytes by preserving, protecting, or promoting mitochondrial function.

Regulatory Mechanism of Autophagy in Premature Ovarian Failure

Premature ovarian failure (POF) is intricately linked to cellular fates such as senescence, apoptosis, and impaired granulosa cell (GC) differentiation, each of which contributes to ovarian dysfunction and follicular depletion. Autophagy is essential in preventing POF by maintaining cellular homeostasis through the degradation and recycling of damaged organelles and proteins, thereby preserving ovarian function and preventing follicular depletion. Recent studies have revealed that the targeted regulation and disruption of autophagy through various molecular mechanisms ultimately lead to the pathogenesis of POF. In this review, we provide a comprehensive analysis of the disruption in regulatory mechanisms of autophagy contributing to POF. Specifically, we elucidate the molecular mechanisms that can be targeted to restore autophagy homeostasis, offering therapeutic potential for the treatment of POF.

A Molecular Perspective and Role of NAD+ in Ovarian Aging

The decline in female fecundity is linked to advancing chronological age. The ovarian reserve diminishes in quantity and quality as women age, impacting reproductive efficiency and the aging process in the rest of the body. NAD+ is an essential coenzyme in cellular energy production, metabolism, cell signaling, and survival. It is involved in aging and is linked to various age-related conditions. Hallmarks associated with aging, diseases, and metabolic dysfunctions can significantly affect fertility by disturbing the delicate relationship between energy metabolism and female reproduction. Enzymes such as sirtuins, PARPs, and CD38 play essential roles in NAD+ biology, which actively consume NAD+ in their enzymatic activities. In recent years, NAD+ has gained much attention for its role in aging and age-related diseases like cancer, Alzheimer's, cardiovascular diseases, and neurodegenerative disorders, highlighting its involvement in various pathophysiological processes. However, its impact on female reproduction is not well understood. This review aims to bridge this knowledge gap by comprehensively exploring the complex interplay between NAD+ biology and female reproductive aging and providing valuable information that could help develop plans to improve women's reproductive health and prevent fertility issues.

L-carnitine fails to rescue chemotherapy injured ovaries by epigenetic changes of transcription factors

Cyclophosphamide (CP), as an anti-cancer drug, is frequently used to treat various types of cancer. A decreased number of ovarian follicles impaired normal ovarian function, and subsequent premature ovarian failure (POF) presented as a side effect of cyclophosphamide usage. These events may eventually affect the fertility rate of individuals. The present study showed the effect of cyclophosphamide on ovarian reserves and the protective effect of L-carnitine (LC) as an antioxidant to prevent POF. To design the study, six to eight-week-old NMRI female mice were divided into three groups: control, cyclophosphamide (CP), and cyclophosphamide + L-carnitine (CP + LC). Mice received drugs intraperitoneally (IP) for 21 days. In the following 24 h after the last injection, both ovaries were used to evaluate the expression of Sohlh1 and Lhx8 genes by Real-time PCR. Furthermore, the alteration of Lhx8 promoter methylation was examined by Methylation-sensitive high-resolution melting analysis (MS-HRM). The present data showed the negative effect of CP on regulator genes of oogenesis including Sohlh1 and Lhx8. In addition, an examination of the epigenetic status of the Lhx8 gene showed a change in promoter methylation of this gene following cyclophosphamide injection. Although, L-carnitine is an effective antioxidant in relieving oxidative stress caused by cyclophosphamide and its damage, in the present study, however, the use of L-carnitine failed to protect the ovaries from changes caused by CP injection. So, using cyclophosphamide can alter the expression of folliculogenesis genes through its effects on epigenetic changes and may cause POF. The results of the present study showed that L-carnitine consumption can't protect the ovaries against the adverse effects of CP.

Endocrine factors associated with infertility in women: an updated review

INTRODUCTION

Infertility is defined as the inability to conceive after unprotected sexual intercourse for at least 12 consecutive months. Our objective is to present an updated narrative review on the endocrine causes of infertility in women.

AREAS COVERED

A comprehensive review was conducted using Scielo, Scopus, and EMBASE databases, comprising 245 articles. The pathophysiology of infertility in women was described, including endocrinopathies such as hypothalamic amenorrhea, hyperprolactinemia, polycystic ovary syndrome, primary ovarian insufficiency, obesity, thyroid dysfunction, and adrenal disorders. The diagnostic approach was outlined, emphasizing the necessity of hormonal studies and ovarian response assessments. Additionally, the treatment plan was presented, commencing with non-pharmacological interventions, encompassing the adoption of a Mediterranean diet, vitamin supplementation, moderate exercise, and maintaining a healthy weight. Subsequently, pharmacological treatment was discussed, focusing on the management of associated endocrine disorders and ovulatory dysfunction.

EXPERT OPINION

This comprehensive review highlights the impact of endocrine disorders on fertility in women, providing diagnostic and therapeutic algorithms. Despite remaining knowledge gaps that hinder more effective treatments, ongoing research and advancements show promise for improved fertility success rates within the next five years. Enhanced comprehension of the pathophysiology behind endocrine causes and the progress in genetic research will facilitate the delivery of personalized treatments, thus enhancing fertility rates.