Age-related changes in Folliculogenesis and potential modifiers to improve fertility outcomes - A narrative review

Advances in cytokine-based herbal medicine against premature ovarian insufficiency: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Premature ovarian insufficiency (POI) refers to a dramatic decrease in the number and/or quality of oocytes in the ovaries before the age of 40 years, and is a key cause of female infertility. The prevalence of POI has been increasing annually and tends to be younger. Researches on the etiology of POI and related pathogenesis are still very limited. Herbal medicine can treat many gynecological diseases. And herbal medicine is effective in reproductive health care such as infertility. In recent years, it has been found that immune modulation by cytokines (CK) can prevent or intervene in POI, and herbal medicine can treat POI by regulating CK to improve ovarian function and fertility.

AIM OF THE STUDY

This review presents an overview of the molecular mechanisms of regulation of POI related CK, and reports the therapeutic effect of herbal medicine on POI including herbal medicine formulas, single herbal medicine, herbal medicine active components and acupuncture. This review provides theoretical support for clinical prevention and treatment of POI, and provides new ideas for researches on herbal medicine treatment of POI.

MATERIALS AND METHODS

We performed a collection of relevant scientific articles from different scientific databases regarding the therapeutic effect of herbal medicine on POI by regulating CK, including PubMed, Web of Science, Wanfang Database, CNKI and other publication resources. The search terms used in this review include, 'premature ovarian insufficiency', 'premature ovarian failure (POF)', 'infertility', 'herbal medicine', 'acupuncture', 'cytokine', 'interleukin (IL)', 'tumor necrosis factor-α (TNF-α)', 'interferon-γ (IFN-γ)', 'transforming growth factor-β (TGF-β)', 'vascular endothelial growth factor (VEGF)', 'immune' and 'inflammation'. This review summarized and analyzed the therapeutic effect of herbal medicine according to the existing experimental and clinical researches.

RESULTS

The results showed that herbal medicine treats POI through CK (including ILs, TNF-α, INF-γ, VEGF, TGF-β and others) and related signaling pathways, which regulates reproductive hormones disorder, reduces ovarian inflammatory damage, oxidative stress, apoptosis and follicular atresia, improves ovarian pathological damage and ovarian reserve function.

CONCLUSIONS

This review enriches the theory of POI treatments based on herbal medicine by regulating CK. The specific mechanisms of action and clinical researches on the treatment of POI by herbal medicine should be strengthened in order to promote the application of herbal medicine in the clinic and provide new ideas and better choices for the treatment of POI.

Role of oxylipins in ovarian function and disease: A comprehensive review

Ovaries are essential for healthy female reproduction, with the follicles as their fundamental functional units, which consist of an oocyte and surrounding granulosa cells. The development and formation of follicles in the ovaries are closely linked to reproductive health. Oxylipins refer to oxidative metabolites produced from the oxidation of polyunsaturated fatty acids, either through automatic oxidation or with the help of specific enzymes. They play crucial regulatory roles in the immune system, oxidative stress, and inflammatory reactions and are intimately linked to the development of numerous illnesses, such as diabetes, heart disease, asthma, and Alzheimer's disease. Furthermore, oxylipins have a complex relationship with ovarian function, and both prostaglandins and leukotrienes produced by arachidonic acid affect processes such as follicle growth and development, ovulation, and hormone regulation. The synthesis and metabolism of oxylipins in the ovaries are finely regulated. Oxylipin dysregulation has been linked to various ovarian diseases, including endometriosis, polycystic ovary syndrome, ovarian cancer, and premature ovarian insufficiency. In addition, potential therapeutic targets and interventions targeting the oxylipin pathway for the treatment of ovarian diseases have become a prominent research focus, including regulating the enzymes responsible for oxylipin synthesis, using anti-inflammatory agents, and regulating lipid metabolism. Recent research has been directed towards improving the reproductive outcomes of women with ovarian diseases through this series of interventions. An overview of the role of oxylipins in ovarian function and disease is provided in this article, which will aid researchers in understanding the current state of the field and in identifying future directions.

MiR-425-5p suppression of Crebzf regulates oocyte aging via chromatin modification

Female infertility due to declining oocyte quality with age remains a significant challenge for patients and physicians, despite extensive research efforts. Recent studies suggest that microRNAs (miRNAs), which respond to various stressors in the aging process, may provide a promising solution. With the approval of small RNA drugs for clinical use, miRNA-based treatment of oocyte aging appears to be a viable option. Through high-throughput sequencing, miR-425-5p was identified as the only miRNA elevated under natural aging and oxidative stress. Microinjection of inhibitors to inhibit miR-425-5p effectively improved compromised phenotypes of old oocytes in vitro. Further investigation revealed that Crebzf acts as a mediator of miR-425-5p's age-related functions in old oocytes. In vivo treatment with miR-425-5p antagomirs significantly improved impaired oocyte development in reproductively old females by targeting Crebzf. Single-cell RNA sequencing revealed that Crebzf plays a vital role in regulating mRNAs targeting histone H3, trimethylated lysine 4 (H3K4me3), a crucial marker for transcriptional silencing. Overexpression of miR-425-5p could hinder oocyte maturation by downregulating Crebzf expression and disrupting transcriptional regulation. Our findings provide new insights into the potential of miR-425-5p antagomirs as a treatment for female infertility and highlight an elegant mechanism by which miR-425-5p inhibition of Crebzf inhibits a developmental switch in GV oocytes by regulating a group of histone methyltransferase mRNAs.

High-fat diet-negative impact on female fertility: from mechanisms to protective actions of antioxidant matrices

Introduction

Excessive calorie intake poses a significant threat to female fertility, leading to hormonal imbalances and reproductive challenges. Overconsumption of unhealthy fats exacerbates ovarian dysfunction, with an overproduction of reactive oxygen species causing oxidative stress, impairing ovarian follicle development and leading to irregular ovulation and premature ovarian failure. Interest in biological matrices with high antioxidant properties to combat diet-related oxidative stress has grown, as they contain various bioactive factors crucial for neutralizing free radicals potentially preventing female reproductive health. This systematic review evaluates the female reproductive impact of biological matrices in mitigating oxidative damages induced by over calory habits and, in particular, high fat diets.

Methods

A comparative approach among mammalian models was utilized to interpret literature available data. This approach specifically investigates the antioxidant mechanisms of biological matrices on early and late ovarian folliculogenesis, under physiological and hormone-induced female reproductive cycle. Adhering to the PRISMA 2020 guidelines, only English-language publications from peer-reviewed international indexes were considered.

Results

The analysis of 121 publications meeting the inclusion criteria facilitated the identification of crucial components of biological matrices. These components, including carbocyclic sugars, phytonutrients, organosulfur compounds, and vitamins, were evaluated for their impact on ovarian follicle resilience, oocyte quality, and reproductive lifespan. The detrimental effects of oxidative stress on female fertility, particularly exacerbated by high saturated fat diets, are well-documented. In vivo studies across mammalian preclinical models have underscored the potential of antioxidants derived from biological matrices to mitigate diet-induced conditions. These antioxidants enhance steroidogenesis and ovarian follicle development, thereby improving oocyte quality. Additionally, discussions within these publications emphasized the clinical significance of these biological matrices, translating research findings into practical applications for female health.

Conclusion

Further research is essential to fully exploit the potential of these matrices in enhancing female reproduction and mitigating the effects of diets rich in fatty acids. This requires intensified in vitro studies and comprehensive collection of in vivo data before clinical trials. The promotion of ovarian resilience offers promising avenues for enhancing understanding and advancing female reproductive health world-wide.

Nutritional supplements and IVF: an evidence-based approach

Many women undergoing IVF take supplements during treatment. The purpose of this review was to systematically review these nutritional supplements. The therapies studied are dehydroepiandrosterone (DHEA), melatonin, co-enzyme Q10 (CoQ1O), carnitine, selenium, vitamin D, myo-inositol, omega-3, Chinese herbs and dietary interventions. A literature search up to May 2023 was undertaken. The data suggest that a simple nutritional approach would be to adopt a Mediterranean diet. With regards to supplements to treat a potential poor ovarian response to ovarian stimulation, starting DHEA and COQ-10 before cycle commencement is better than control therapies. Furthermore, medication with CoQ10 may have some merit, although it is unclear whether its place is for older women, for those with a poor response to ovarian stimulation or for poor embryonic development. There appears a benefit for some IVF outcomes for the use of melatonin, although it is unclear what group of patients would derive the benefit and the appropriate dosing regimen. For women with polycystic ovary syndrome, there may be a benefit to the use of myo-inositol, although again the dosing regimen is unclear. Furthermore, the place of vitamin D supplementation has yet to be clarified, and supplementation with omega-3 free fatty acids may lead to improvements in clinical and embryological IVF outcomes.

Growth factors and female reproduction in vertebrates

Female reproductive efficiency is influenced by the outcomes of various processes, including folliculogenesis, apoptosis, response to gonadotropin signaling, oocyte maturation, and ovulation. The role of hormones in regulating these processes and other reproductive activities has been well established. It is becoming increasingly evident that in addition to well-characterized hormones, growth factors play vital roles in regulating some of these reproductive activities. Growth factors and their receptors are widely distributed in vertebrate ovaries at different stages of ovarian development, indicating their involvement in intraovarian reproductive functions. In the ovary, cell surface receptors allow growth factors to regulate intraovarian reproductive activities. Understanding these actions in the reproductive axis would provide a tool to target growth factors and/or their receptors to yield desirable reproductive outcomes. These include enrichment of in vitro maturation and fertilization culture media, and management of infertility. This review discusses some widely characterized growth factors belonging to the TGF, EGF, IGF, FGF, and BDNF family of peptides and their role in female reproduction in vertebrates, with a focus on mammals.

Chronic low-grade inflammation and ovarian dysfunction in women with polycystic ovarian syndrome, endometriosis, and aging

The ovarian microenvironment is critical for follicular development and oocyte maturation. Maternal conditions, including polycystic ovary syndrome (PCOS), endometriosis, and aging, may compromise the ovarian microenvironment, follicular development, and oocyte quality. Chronic low-grade inflammation can induce oxidative stress and tissue fibrosis in the ovary. In PCOS, endometriosis, and aging, pro-inflammatory cytokine levels are often elevated in follicular fluids. In women with obesity and PCOS, hyperandrogenemia and insulin resistance induce ovarian chronic low-grade inflammation, thereby disrupting follicular development by increasing oxidative stress. In endometriosis, ovarian endometrioma-derived iron overload can induce chronic inflammation and oxidative stress, leading to ovarian ferroptosis and fibrosis. In inflammatory aging (inflammaging), senescent cells may secrete senescence-associated secretory phenotype factors, causing chronic inflammation and oxidative stress in the ovary. Therefore, controlling chronic low-grade inflammation and fibrosis in the ovary would present a novel therapeutic strategy for improving the follicular microenvironment and minimizing ovarian dysfunction.

The constructive and destructive impact of autophagy on both genders' reproducibility, a comprehensive review

Reproduction is characterized by a series of massive renovations at molecular, cellular, and tissue levels. Recent studies have strongly tended to reveal the involvement of basic molecular pathways such as autophagy, a highly conserved eukaryotic cellular recycling, during reproductive processes. This review comprehensively describes the current knowledge, updated to September 2022, of autophagy contribution during reproductive processes in males including spermatogenesis, sperm motility and viability, and male sex hormones and females including germ cells and oocytes viability, ovulation, implantation, fertilization, and female sex hormones. Furthermore, the consequences of disruption in autophagic flux on the reproductive disorders including oligospermia, azoospermia, asthenozoospermia, teratozoospermia, globozoospermia, premature ovarian insufficiency, polycystic ovarian syndrome, endometriosis, and other disorders related to infertility are discussed as well.Abbreviations: AKT/protein kinase B: AKT serine/threonine kinase; AMPK: AMP-activated protein kinase; ATG: autophagy related; E2: estrogen; EDs: endocrine disruptors; ER: endoplasmic reticulum; FSH: follicle stimulating hormone; FOX: forkhead box; GCs: granulosa cells; HIF: hypoxia inducible factor; IVF: in vitro fertilization; IVM: in vitro maturation; LCs: Leydig cells; LDs: lipid droplets; LH: luteinizing hormone; LRWD1: leucine rich repeats and WD repeat domain containing 1; MAP1LC3: microtubule associated protein 1 light chain 3; MAPK: mitogen-activated protein kinase; MTOR: mechanistic target of rapamycin kinase; NFKB/NF-kB: nuclear factor kappa B; P4: progesterone; PCOS: polycystic ovarian syndrome; PDLIM1: PDZ and LIM domain 1; PI3K: phosphoinositide 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; PtdIns3K: class III phosphatidylinositol 3-kinase; POI: premature ovarian insufficiency; ROS: reactive oxygen species; SCs: Sertoli cells; SQSTM1/p62: sequestosome 1; TSGA10: testis specific 10; TST: testosterone; VCP: vasolin containing protein.

Alteration of relative telomere length and telomerase reverse transcriptase expression in the granulosa cells of women during aging and assessment of in vitro fertilization outcomes

Telomere attrition plays a critical role in the reproductive aging process in humans. Telomere length (TL) is typically regulated by telomerase, the main component of which is telomerase reverse transcriptase (TERT). The aim of the present study was to investigate the changes of relative TL (RTL) and TERT expression in granulosa cells (GCs) during aging and its association with reproduction. Clinical data on the frozen‑thawed embryo transfer cycles of older (>35 year old) and younger (≤35 year old) women from a single center over a 3‑year period were retrospectively analyzed. Preimplantation genetic testing for chromosome aneuploidies in older women during the same period was also analyzed. Following the analysis of the data, several biological characteristics of senescent GCs were explored. In addition, a total of 160 women who were undergoing their first fresh cycle of in vitro fertilization (IVF) or intracytoplasmic sperm injection were included in the study. GCs were collected from all participants. The changes of RTL and TERT expression in GCs during aging were investigated using quantitative PCR and western blotting. The associations of RTL and TERT with IVF outcomes were also assessed. The clinical data demonstrated that the pregnancy and live birth rates of women aged >35 years were ~20% lower than those of women aged ≤35 years, and the number of embryos with aneuploidy was 7‑fold of that without euploidy in the older age group. An aging‑induced change in follicle stimulating hormone receptor expression was observed. A shorter TL and increased TERT expression were detected in the older women. A significant inverse correlation between the expression levels of TERT and oocyte yield was identified. However, no association of RTL and TERT with blastocyst formation rate and the probability of clinical pregnancy was detected. It may be concluded that RTL and TERT alterations in GCs are potential determinants of ovarian aging. TERT expression in GCs appears to be a potential biomarker for the prediction of ovarian response, which provides a novel strategy for the assessment of female fertility.

Facilitation of Ovarian Response by Mechanical Force-Latest Insight on Fertility Improvement in Women with Poor Ovarian Response or Primary Ovarian Insufficiency

The decline in fertility in aging women, especially those with poor ovarian response (POR) or primary ovarian insufficiency (POI), is a major concern for modern IVF centers. Fertility treatments have traditionally relied on gonadotropin- and steroid-hormone-based IVF practices, but these methods have limitations, especially for women with aging ovaries. Researchers have been motivated to explore alternative approaches. Ovarian aging is a complicated process, and the deterioration of oocytes, follicular cells, the extracellular matrix (ECM), and the stromal compartment can all contribute to declining fertility. Adjunct interventions that involve the use of hormones, steroids, and cofactors and gamete engineering are two major research areas aimed to improve fertility in aging women. Additionally, mechanical procedures including the In Vitro Activation (IVA) procedure, which combines pharmacological activators and fragmentation of ovarian strips, and the Whole Ovary Laparoscopic Incision (WOLI) procedure that solely relies on mechanical manipulation in vivo have shown promising results in improving follicle growth and fertility in women with POR and POI. Advances in the use of mechanical procedures have brought exciting opportunities to improve fertility outcomes in aging women with POR or POI. While the lack of a comprehensive understanding of the molecular mechanisms that lead to fertility decline in aging women remains a major challenge for further improvement of mechanical-manipulation-based approaches, recent progress has provided a better view of how these procedures promote folliculogenesis in the fibrotic and avascular aging ovaries. In this review, we first provide a brief overview of the potential mechanisms that contribute to ovarian aging in POI and POR patients, followed by a discussion of measures that aim to improve ovarian folliculogenesis in aging women. At last, we discuss the likely mechanisms that contribute to the outcomes of IVA and WOLI procedures and potential future directions.

Identification of potential angiogenic biomarkers in human follicular fluid for predicting oocyte maturity

Background

Angiogenesis in folliculogenesis contributes to oocyte developmental competence in natural and in vitro fertilization (IVF) cycles. Therefore, the identification of key angiogenic factors in follicular fluid (FF) during folliculogenesis is clinically significant and important for in vitro fertilization. This study aims to identify the key angiogenic factors in FF for predicting oocyte maturity during in vitro fertilization.

Materials and methods

Forty participants who received ovarian stimulation using a GnRH antagonist protocol in their first in vitro fertilization treatment were recruited. From each patient, two follicular samples (one preovulatory follicle, > 18 mm; one mid-antral follicle, < 14 mm) were collected without flushing during oocyte retrieval. In total, 80 FF samples were collected from 40 patients. The expression profiles of angiogenesis-related proteins in FF were analyzed via Luminex high-performance assays. Recorded patient data included antral follicle count, anti-müllerian hormone, age, and BMI. Serum samples were collected on menstrual cycle day 2, the trigger day, and the day of oocyte retrieval. Hormone concentrations including day 2 FSH/LH/E2/P4, trigger day E2/LH/P4, and retrieval day E2/LH/P4 were measured by chemiluminescence assay.

Results

Ten angiogenic factors were highly expressed in FF: eotaxin, Gro-α, IL-8, IP-10, MCP-1, MIG, PAI-1 (Serpin), VEGF-A, CXCL-6, and HGF. The concentrations of eotaxin, IL-8, MCP1, PAI-1, and VEGF-A were significantly higher in preovulatory follicles than those in mid-antral follicles, while the Gro-α and CXCL-6 expressional levels were lower in preovulatory than in mid-antral follicles (p < 0.05). Logistic regression and receiver operating characteristic (ROC) analysis revealed that VEGF-A, eotaxin, and CXCL-6 were the three strongest predictors of oocyte maturity. The combination of VEGF-A and CXCL-6 predicted oocyte maturity with a higher sensitivity (91.7%) and specificity (72.7%) than other combinations.

Conclusion

Our findings suggest that VEGF-A, eotaxin, and CXCL-6 concentrations in FF strongly correlate with oocyte maturity from the mid-antral to preovulatory stage. The combination of VEGF-A and CXCL-6 exhibits a relatively good prediction rate of oocyte maturity during in vitro fertilization.

Fertility in Acromegaly: A Single-Center Experience of Female Patients During Active Disease and After Disease Remission

CONTEXT

Fertility represents a major concern in patients with acromegaly.

OBJECTIVE

The current retrospective study aimed to investigate gonadal function and fertility rates in acromegalic women.

METHODS

In this referral-center study, 50 acromegalic women with disease onset within reproductive age were evaluated for prevalence of gonadal dysfunction and infertility. Anthropometric, metabolic, hormonal parameters, and gynecological ultrasound were evaluated at diagnosis and after disease control. Data about menstrual disturbances, pregnancy, and polycystic ovarian morphology (PCOM) were investigated at disease onset, at diagnosis, and after disease control.

RESULTS

At presumed disease onset, menstrual disturbances were reported in 32% of patients. Uterine leiomyoma, ovarian cysts, and PCOM were diagnosed in 18%, 12%, and 8%, respectively; 36.8% of patients were infertile. At diagnosis, menstrual disturbances were found in 58.1% (P = .02), being significantly more prevalent in patients with higher insulin-like growth factor-I quartiles (Q) (P = .03, Q1 vs Q4). Gynecological ultrasound revealed uterine leiomyoma, ovarian cysts, and PCOM in 39.1% (P = .04), 28.2% (P = .09), and 13% (P = .55), respectively. The infertility rate was 100% (P = .02). At disease control, menstrual disturbances were slightly decreased as compared to diagnosis (P = .09). Noteworthy, menstrual disturbances (P = .05) and particularly amenorrhea (P = .03) were significantly more frequent in patients with active disease duration greater than 5 years (median) as compared to those achieving disease control in less than 5 years. Among patients with pregnancy desire, 73.3% conceived at least once, with resulting infertility significantly decreased compared to diagnosis (26.7%; P = .01). At-term deliveries, preterm deliveries, and spontaneous abortions were recorded in 86.7%, 6.6%, and 6.6%, respectively, of the 15 pregnancies reported by the patients. No neonatal malformations and/or abnormalities were recorded.

CONCLUSION

Gonadal dysfunction and infertility are common in acromegalic women within reproductive age, being directly influenced by disease status and/or duration.