Antioxidants for female subfertility

Impact of dietary antioxidants on female infertility risk: evidence from NHANES

The composite dietary antioxidant index (CDAI) serves as a valuable instrument for evaluating the intake of dietary antioxidants. This research aims to clarify the connection between CDAI and the risk of female infertility by analyzing data from the National Health and Nutrition Examination Survey from 2013 to 2018. Participants underwent two 24-h dietary recall interviews to calculate CDAI. Female infertility was determined through two questionnaires. Logistic regression model, restricted cubic spline and subgroup analysis were employed to examine the association between CDAI and female infertility. The study encompassed 2162 participants. Participants with female infertility had lower CDAI levels compared to those without. Following adjustment for confounding variables, a negative association between CDAI levels and female infertility was observed (Q4 vs. Q1, OR [95% CI] 0.392 [0.193, 0.795], P = 0.016). RCS demonstrated a statistically significant linear negative relationship between CDAI and female infertility. Subgroup analysis showed no significant interaction. This study illustrates a negative link between the CDAI and female infertility, indicating that higher consumption of dietary antioxidants may be associated with a reduced risk of female infertility. Additional rigorously designed prospective studies are necessary to validate these results.

Supplementation practices among pregnant women and those trying to conceive: a population-representative survey in Vancouver, Canada

Dietary supplements including vitamins, minerals, and natural health products are commonly consumed by those aiming to optimize fertility and pregnancy outcomes. The aim of this survey was to describe supplementation practices among individuals who were pregnant or trying to conceive in Vancouver, Canada. An online survey was conducted among 500 individuals who were pregnant (n = 250) or trying to conceive (n = 250). Participants met a substantial proportion of vitamin and mineral recommendations through supplements alone. Exceptions included calcium, magnesium, and choline, with median (interquartile range (IQR)) supplementation doses reported by those who were pregnant and trying to conceive, respectively, of: 250 (200 and 250 mg) and 250 (200 and 250 mg), 50 (50 and 75 mg) and 50 (50 and 90 mg), and 53 (10 and 150 mg) and 55 (10 and 100 mg), as compared to perinatal recommendations of 1000 mg/day (calcium), 350 mg/day (magnesium), and 450 mg/day (choline). Conversely, median (IQR) doses of folate reported by those who were pregnant and trying to conceive, respectively, were: 1000 (780 and 1000 µg) and 1000 (800 and 1000 µg), with ∼70% overall (337/471) reporting doses ≥1000 µg (the tolerable upper intake level). Most participants (451/500; 90%) reported supplementation with a prenatal multivitamin; of these, 83% reported that supplementation occurred daily. Overall, as diet was not considered, we cannot ascertain whether recommendations for calcium, magnesium, and choline were met through the combination of supplements and foods; however, we believe that additional supplementation with choline may be required to meet recommendations in pregnancy. Excessive folate supplementation has been previously identified as a concern throughout North America; here, we provide further evidence for excessively high doses consumed via supplements.

Clinical predictive value of pre-pregnancy tests for unexplained recurrent spontaneous abortion: a retrospective study

Introduction

Early prediction and intervention are crucial for the prognosis of unexplained recurrent spontaneous abortion (uRSA). The main purpose of this study is to establish a risk prediction model for uRSA based on routine pre-pregnancy tests, in order to provide clinical physicians with indications of whether the patients are at high risk.

Methods

This was a retrospective study conducted at the Prenatal Diagnosis Center of Henan Provincial People's Hospital between January 2019 and December 2022. Twelve routine pre-pregnancy tests and four basic personal information characteristics were collected. Pre-pregnancy tests include thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine thyroid (FT4), thyroxine (TT4), total triiodothyronine (TT3), peroxidase antibody (TPO-Ab), thyroid globulin antibody (TG-Ab), 25-hydroxyvitamin D [25-(OH) D], ferritin (Ferr), Homocysteine (Hcy), vitamin B12 (VitB12), folic acid (FA). Basic personal information characteristics include age, body mass index (BMI), smoking history and drinking history. Logistic regression analysis was used to establish a risk prediction model, and receiver operating characteristic (ROC) curve and decision curve analysis (DCA) were employed to evaluate the performance of prediction model.

Results

A total of 140 patients in uRSA group and 152 women in the control group were randomly split into a training set (n = 186) and a testing set (n = 106). Chi-square test results for each single characteristic indicated that, FT3 (p = 0.018), FT4 (p = 0.048), 25-(OH) D (p = 0.013) and FA (p = 0.044) were closely related to RSA. TG-Ab and TPO-Ab were also important characteristics according to clinical experience, so we established a risk prediction model for RSA based on the above six characteristics using logistic regression analysis. The prediction accuracy of the model on the testing set was 74.53%, and the area under ROC curve was 0.710. DCA curve indicated that the model had good clinical value.

Conclusion

Pre-pregnancy tests such as FT3, FT4, TG-Ab, 25-(OH)D and FA were closely related to uRSA. This study successfully established a risk prediction model for RSA based on routine pre-pregnancy tests.

Reproductive Ageing: Metabolic contribution to age-related chromosome missegregation in mammalian oocytes

In brief

Chromosome missegregation and declining energy metabolism are considered to be unrelated features of oocyte ageing that contribute to poor reproductive outcomes. Given the bioenergetic cost of chromosome segregation, we propose here that altered energy metabolism during ageing may be an underlying cause of age-related chromosome missegregation and aneuploidy.

Abstract

Advanced reproductive age in women is a major cause of infertility, miscarriage and congenital abnormalities. This is principally caused by a decrease in oocyte quality and developmental competence with age. Oocyte ageing is characterised by an increase in chromosome missegregation and aneuploidy. However, the underlying mechanisms of age-related aneuploidy have not been fully elucidated and are still under active investigation. In addition to chromosome missegregation, oocyte ageing is also accompanied by metabolic dysfunction. In this review, we integrate old and new perspectives on oocyte ageing, chromosome segregation and metabolism in mammalian oocytes and make direct links between these processes. We consider age-related alterations to chromosome segregation machinery, including the loss of cohesion, microtubule stability and the integrity of the spindle assembly checkpoint. We focus on how metabolic dysfunction in the ageing oocyte disrupts chromosome segregation machinery to contribute to and exacerbate age-related aneuploidy. More specifically, we discuss how mitochondrial function, ATP production and the generation of free radicals are altered during ageing. We also explore recent developments in oocyte metabolic ageing, including altered redox reactions (NAD+ metabolism) and the interactions between oocytes and their somatic nurse cells. Throughout the review, we integrate the mechanisms by which changes in oocyte metabolism influence age-related chromosome missegregation.

Chemical reversion of age-related oocyte dysfunction fails to enhance embryo development in a bovine model of postovulatory aging

PURPOSE

There are no clinical treatments to prevent/revert age-related alterations associated with oocyte competence decline in the context of advanced maternal age. Those alterations have been attributed to oxidative stress and mitochondrial dysfunction. Our study aimed to test the hypothesis that in vitro maturation (IVM) medium supplementation with antioxidants (resveratrol or phloretin) may revert age-related oocyte competence decline.

METHODS

Bovine immature oocytes were matured in vitro for 23 h (young) and 30 h (aged). Postovulatory aged oocytes (control group) and embryos obtained after fertilization were examined and compared with oocytes supplemented with either 2 μM of resveratrol or 6 μM phloretin (treatment groups) during IVM.

RESULTS

Aged oocytes had a significantly lower mitochondrial mass and proportion of mitochondrial clustered pattern, lower ooplasmic volume, higher ROS, lower sirtuin-1 protein level, and a lower blastocyst rate in comparison to young oocytes, indicating that postovulatory oocytes have a lower quality and developmental competence, thus validating our experimental model. Supplementation of IVM medium with antioxidants prevented the generation of ROS and restored the active mitochondrial mass and pattern characteristic of younger oocytes. Moreover, sirtuin-1 protein levels were also restored but only following incubation with resveratrol. Despite these findings, the blastocyst rate of treatment groups was not significantly different from the control group, indicating that resveratrol and phloretin could not restore the oocyte competence of postovulatory aged oocytes.

CONCLUSION

Resveratrol and phloretin can both revert the age-related oxidative stress and mitochondrial dysfunction during postovulatory aging but were insufficient to enhance embryo developmental rates under our experimental conditions.

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.

Reactive oxygen species-scavenging nanomaterials for the prevention and treatment of age-related diseases

With increasing proportion of the elderly in the population, age-related diseases (ARD) lead to a considerable healthcare burden to society. Prevention and treatment of ARD can decrease the negative impact of aging and the burden of disease. The aging rate is closely associated with the production of high levels of reactive oxygen species (ROS). ROS-mediated oxidative stress in aging triggers aging-related changes through lipid peroxidation, protein oxidation, and DNA oxidation. Antioxidants can control autoxidation by scavenging free radicals or inhibiting their formation, thereby reducing oxidative stress. Benefiting from significant advances in nanotechnology, a large number of nanomaterials with ROS-scavenging capabilities have been developed. ROS-scavenging nanomaterials can be divided into two categories: nanomaterials as carriers for delivering ROS-scavenging drugs, and nanomaterials themselves with ROS-scavenging activity. This study summarizes the current advances in ROS-scavenging nanomaterials for prevention and treatment of ARD, highlights the potential mechanisms of the nanomaterials used and discusses the challenges and prospects for their applications.

Assessment of melatonin's therapeutic effectiveness against hepatic steatosis induced by a high-carbohydrate high-fat diet in rats

Several studies have demonstrated the protective effects of melatonin against metabolic diseases, such as liver steatosis. However, its therapeutic effects have received less scrutiny. The present study aimed to explore melatonin's therapeutic effectiveness in treating non-alcoholic fatty liver disease (NAFLD) induced by a high-carbohydrate high-fat (HCHF) diet in rats. The NAFLD was developed in male Wistar rats using an HCHF diet for 8 weeks. Afterward, they were given melatonin orally for four weeks at doses of 5 mg/kg, 10 mg/kg, and 30 mg/kg, along with the HCHF diet. In addition, six age-matched healthy rats received the highest dose of melatonin (30 mg/kg) for the same duration. Rats on the HCHF diet exhibited obesity, dyslipidemia, hyperglycemia, glucose intolerance, insulin resistance, inflammation, oxidative stress, and liver injury (steatosis). Melatonin treatment at 10 mg/kg and 30 mg/kg reduced body weight, adiposity index, oxidative damage, and inflammation but did not affect impaired glucose metabolism induced by the HCHF diet. Meanwhile, the highest dose of melatonin (30 mg/kg) reduced the liver steatosis index in HCHF rats but caused mild liver damage in healthy rats. In conclusion, using melatonin demonstrated positive outcomes in treating NAFLD induced by the HCHF diet in rats, with no noteworthy effects observed in healthy rats. A moderate dosage of 10 mg/kg of melatonin proved to be a safer and more efficient method for reducing HCHF diet-induced NAFLD in rats. Higher melatonin doses should be cautiously administered due to potential disruptions in lipid metabolism and the risk of liver complications.

Chromosome ends and the theory of marginotomy: implications for reproduction

Telomeres are the protective structures located at the ends of linear chromosomes. They were first described in the 1930s, but their biology remained unexplored until the early 70s, when Alexey M. Olovnikov, a theoretical biologist, suggested that telomeres cannot be fully copied during DNA replication. He proposed a theory that linked this phenomenon with the limit of cell proliferation capacity and the "duration of life" (theory of marginotomy), and suggested a potential of telomere lenghthening for the prevention of aging (anti-marginotomy). The impact of proliferative telomere shortening on life expectancy was later confirmed. In humans, telomere shortening is counteracted by telomerase, an enzyme that is undetectable in most adult somatic cells, but present in cancer cells and adult and embryonic stem and germ cells. Although telomere length dynamics are different in male and female gametes during gametogenesis, telomere lengths are reset at the blastocyst stage, setting the initial length of the species. The role of the telomere pathway in reproduction has been explored for years, mainly because of increased infertility resulting from delayed childbearing. Short telomere length in ovarian somatic cells is associated to decreased fertility and higher aneuploidy rates in embryos. Consequently, there is a growing interest in telomere lengthening strategies, aimed at improving fertility. It has also been observed that lifestyle factors can affect telomere length and improve fertility outcomes. In this review, we discuss the implications of telomere theory in fertility, especially in oocytes, spermatozoa, and embryos, as well as therapies to enhance reproductive success.

Expert consensus on the role of supplementation in obstetrics and gynecology using modified delphi method

PURPOSE

To reach a consensus among obstetrics and gynecology experts on the effects of micronutrient supplementation on fertility and pregnancy to aid clinicians in decision-making and create a unified approach to managing micronutrient deficiencies in women, by performing a modified Delphi study.

METHODS

A three-round modified Delphi process was conducted among a Delphi panel of 38 Egyptian experts to define recommendations regarding the role of supplementation on fertility and pregnancy in women of reproductive age. A literature review was performed and supporting evidence was graded to help guide the recommendations based on available evidence.

RESULTS

A total of 62 statements were developed for discussion and voting. Out of the 62 statements, 60 statements reached expert consensus. Statements were divided into two domains. The first domain discussed the role of supplementation in fertility: optimizing natural fertility, polycystic ovary syndrome (PCOS), in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI), unexplained infertility, and endometriosis, whereas the second domain was concerned with the role of supplementation in pregnancy during the prenatal, antenatal, and postnatal periods.

CONCLUSION

In this work, a modified Delphi methodology was implemented to reach a consensus on the use of micronutrient supplementation in women of reproductive age. These recommendations can help clinicians in their practice, guide future research, and identify gaps in the market for the pharmaceutical industry. This clinical guidance can be extrapolated to similar communities.

Associations of Nutrients and Dietary Preferences with Recurrent Pregnancy Loss and Infertility

This review examines associations of nutrients and dietary preferences with recurrent pregnancy loss (RPL), miscarriage, and infertility. Research articles, reviews, and meta-analyses of RPL and infertility that focused on nutrition, meals, and lifestyle were reviewed, and associations of nutrients and dietary preferences with pregnancy are discussed in relation to recent research findings. Studies related to RPL were given the highest priority, followed by those dealing with miscarriage and infertility. Multivitamin supplements-even when lacking folic acid or vitamin A-reduced total fetal loss. High-dose folic acid supplementation before conception reduced the risk of miscarriage and stillbirth. A meta-analysis revealed a strong association of vitamin D deficiency/insufficiency with miscarriage. Another meta-analysis revealed that seafood and dairy products reduced the risk of miscarriage, whereas a caffeine intake of 300 mg/day or more was associated with miscarriage. A balanced diet that included nutrients with antioxidant properties helped prevent miscarriage, whereas a diet that included processed foods and nutrients with proinflammatory effects increased the risk of miscarriage. Associations of nutrients with RPL warrant further research.

[Sleep disorders during pregnancy]

Pregnancy is associated with a number of physiological changes in a woman's body, which in turn affect the quality and duration of sleep. According to research, insomnia and other sleep disorders are associated with a high risk of adverse pregnancy outcomes, as well as postpartum complications. Understanding the mechanisms of sleep disorders during pregnancy is necessary to form an integrated approach in the management of this group of patients. The appointment of medicinal and non-medicinal therapies, as well as general recommendations for lifestyle correction in order to treat sleep disorders, is focused on the safe and prolific effect of a particular drug on the mother and fetus. This review also examined the safety profile of commonly used groups of drugs for sleep disorders during pregnancy.

Coenzyme Q10 Stimulate Reproductive Vatality

Female infertility and pregnancy maintenance are associate with various factors, including quantity and quality of oocytes, genital inflammation, endometriosis, and other diseases. Women are even diagnosed as unexplained infertility or unexplained recurrent spontaneous abortion when failed to achieve pregnancy with current treatment, which are urgent clinical issues need to be addressed. Coenzyme Q10 (CoQ10) is a lipid-soluble electron carrier in the mitochondrial electron transport chain. It is not only essential for the mitochondria to produce energy, but also function as an antioxidant to maintain redox homeostasis in the body. Recently, the capacity of CoQ10 to reduce oxidative stress (OS), enhance mitochondrial activity, regulate gene expression and inhibit inflammatory responses, has been discovered as a novel adjuvant in male reproductive performance enhancing in both animal and human studies. Furthermore, CoQ10 is also proved to regulate immune balance, antioxidant, promote glucose and lipid metabolism. These properties will bring highlight for ovarian dysfunction reversing, ovulation ameliorating, oocyte maturation/fertilization promoting, and embryonic development optimizing. In this review, we systematically discuss the pleiotropic effects of CoQ10 in female reproductive disorders to investigate the mechanism and therapeutic potential to provide a reference in subsequent studies.

Role of oxidative stress in male infertility

Abstract

Infertility affects millions of couples worldwide. Oxidative stress (OS) causes peroxidation of lipids and damage to spermatozoa, thus, reducing the quality of seminal parameters. In addition, the differences in the levels of antioxidants and reactive oxygen species (ROS) caused by intrinsic and extrinsic variables linked to lifestyle, diet, genetics, and OS also contribute to male infertility. High levels of ROS result in sperm damage of sperm parameters due to lipid peroxidation and oxidation of proteins. Other significant causes of ROS include changes in sex hormone levels, sperm DNA damage, including mutations, and immature spermatozoa. Treating the root causes of OS, by changing one's lifestyle, as well as antioxidant therapy, may be helpful strategies to fight OS-related infertility. However, the determination of male infertility induced by OS is currently a challenge in the field of reproductive health research. This review intends to describe the role of oxidative stress on male infertility and the current understanding of its management.

Lay summary

The inability to conceive affects many couples globally. Oxidative stress refers to imbalances between different oxygen species which can lead to male fertility problems by damaging sperm and semen. Oxidative stress may be caused by several factors, including diets high in fats, sugars and processed foods, lifestyle (including smoking, alcohol consumption and having a sedentary lifestyle), and genetics. Treatment that focuses on the root cause may help combat male infertility. However, there is currently no consensus on the best way to treat male fertility problems, particularly those associated with oxidative stress. This paper describes the role of oxidative stress on male infertility and discusses the current techniques employed in treating male fertility issues.

Food & Fertility Study: study protocol for a Danish multicentre prospective cohort study investigating the association between food intake and semen quality, pregnancy and birth outcomes in infertile women and men

INTRODUCTION

Worldwide infertility is highly prevalent, and lifestyle factors, such as food intake, could have an essential role in the success of a fertility treatment. The literature is not consistent and adequate for recommendations to the increasing number of women and men of reproductive age who ask for lifestyle guidance. Therefore, the aims of the Food & Fertility Study will be to investigate the possible association between food intake and semen quality in men, and pregnancy and live birth rates in women undergoing intrauterine insemination or assisted reproductive technology treatment.

METHODS AND ANALYSIS

The Food & Fertility Study is a multicentre prospective cohort study which plans to enrol a total of 4000 women and men between 2022 and 2024. Data collection will take place in four fertility clinics through a web-based Food Frequency Questionnaire. Data on sperm quality and pregnancy and live birth rates will be obtained from medical records and national registers.

ETHICS AND DISSEMINATION

The study is registered with and approved by the Danish Data Protection Agency, the North Denmark Region (j.nr: 2019-055298). Further, a Statement of Work and a Master Collaboration Agreement have been submitted and approved by the regional legal departments (AGR-2019-731-9667). Dissemination of the results will be through national and international conferences, in scientific environments, in the form of lectures to the broader public, and by peer-reviewed publications in international scientific journals.

TRIAL REGISTRATION NUMBER

NCT05454046.

The Importance of Natural Antioxidants in Female Reproduction

Oxidative stress (OS) has an important role in female reproduction, whether it is ovulation, endometrium decidualization, menstruation, oocyte fertilization, or development andimplantation of an embryo in the uterus. The menstrual cycle is regulated by the physiological concentration of reactive forms of oxygen and nitrogen as redox signal molecules, which trigger and regulate the length of individual phases of the menstrual cycle. It has been suggested that the decline in female fertility is modulated by pathological OS. The pathological excess of OS compared to antioxidants triggers many disorders of female reproduction which could lead to gynecological diseases and to infertility. Therefore, antioxidants are crucial for proper female reproductive function. They play a part in the metabolism of oocytes; in endometrium maturation via the activation of antioxidant signaling pathways Nrf2 and NF-κB; and in the hormonal regulation of vascular action. Antioxidants can directly scavenge radicals and act as a cofactor of highly valuable enzymes of cell differentiation and development, or enhance the activity of antioxidant enzymes. Compensation for low levels of antioxidants through their supplementation can improve fertility. This review considers the role of selected vitamins, flavonoids, peptides, and trace elements with antioxidant effects in female reproduction mechanisms.

Effect of Antioxidant Supplementation on Endometriosis-Related Pain: A Systematic Review

PURPOSE OF REVIEW

This study was conducted to determine the effects of antioxidant supplementation on endometriosis-related chronic pelvic pain, dysmenorrhea, and dyspareunia.

METHODS

PubMed/MEDLINE, Scopus, and Cochrane Library databases and the Google Scholar search engine were searched from early 2012 to 2022 using appropriate keywords for clinical trials receiving antioxidant supplements and reporting endometriosis-related pelvic pain (PROSPERO registration number CRD42022318924). The qualities of the included studies were evaluated using the Joanna Briggs Institute (JBI) Checklists Critical Appraisal Tools and the National Institutes of Health (NIH) quality assessment tool for before-after (Pre-Post) study with no control group. This systematic review was reported according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guideline.

RESULTS

In this systematic review, 8 studies (5 RCTs and 3 non-comparative trials) published in 2012-2022 were included.

CONCLUSIONS

The studies we included showed promising results in the use of antioxidants in endometriosis-related pain. However, many scientific studies are needed for clear statements.

Association of follicle-to-oocyte index and clinical pregnancy in IVF treatment: A retrospective study of 4,323 fresh embryo transfer cycles

Objective

The aim of this study is to investigate whether the follicle-to-oocyte index [FOI: (number of retrieved oocytes/antral follicle count) × 100] was associated with clinical pregnancy after fresh cleavage transfer.

Design

The framework used to organize this study is retrospective cohort analysis.

Setting

The study was performed in a single in vitro fertilization center in a public hospital.

Patients

In total, 4,323 fresh embryo transfer cycles from 1 August 2011 to 31 January 2022 were retrospectively analyzed. Data were designated into three groups according to FOI tertile values.

Interventions

There are no interventions in this study.

Main outcome measure

The primary outcome measure is the clinical pregnancy rate (CPR).

Results

A total of 4,323 patients were included in the study. According to their FOI, patients were divided into low (FOI ≤ 0.70, n = 1,434), medium (FOI = 0.71-0.95, n = 1,070), and high (FOI = 0.96-1.00, n = 1,819) tertile groups. A significant statistical increase in the CPR from the lowest to the highest tertile FOI group was detected (47.28%, 51.78%, and 51.57%; P =0.026). After adjusted for potential confounders, multivariate logistic regression analysis revealed a positive association between FOI and CPR [odds ratio (OR) = 1.57; 95% confidence interval (CI): 1.18-2.11]. Each standard deviation increments in FOI (SD = 0.24) corresponded to a 20% increase in the CPR. Trend analysis also showed that FOI tertile groups were positively associated with CPR (P for trend = 0.010). Smooth curve fitting indicated the existence of a linear relationship across the entire range of FOI. No optimal cutoff value of FOI for prognosing CPR was found in smooth curve fitting analysis. Moreover, subgroup analyses suggested that the association was significantly stronger in the single cleavage transfer cycle (OR = 2.04; 95% CI: 1.14-3.65).

Conclusions

FOI is an independent variable in prediction for CPR in fresh embryo transfer cycle, especially in the single cleavage transfer cycle.

Melatonin in Endometriosis: Mechanistic Understanding and Clinical Insight

Endometriosis is defined as the development of endometrial glands and stroma outside the uterine cavity. Pathophysiology of this disease includes abnormal hormone profiles, cell survival, migration, invasion, angiogenesis, oxidative stress, immunology, and inflammation. Melatonin is a neuroendocrine hormone that is synthesized and released primarily at night from the mammalian pineal gland. Increasing evidence has revealed that melatonin can be synthesized and secreted from multiple extra-pineal tissues where it regulates immune response, inflammation, and angiogenesis locally. Melatonin receptors are expressed in the uterus, and the therapeutic effects of melatonin on endometriosis and other reproductive disorders have been reported. In this review, key information related to the metabolism of melatonin and its biological effects is summarized. Furthermore, the latest in vitro and in vivo findings are highlighted to evaluate the pleiotropic functions of melatonin, as well as to summarize its physiological and pathological effects and treatment potential in endometriosis. Moreover, the pharmacological and therapeutic benefits derived from the administration of exogenous melatonin on reproductive system-related disease are discussed to support the potential of melatonin supplements toward the development of endometriosis. More clinical trials are needed to confirm its therapeutic effects and safety.

Effects of Antioxidant Supplementation on Metabolic Disorders in Obese Patients from Randomized Clinical Controls: A Meta-Analysis and Systematic Review

Purpose

This systematic review and meta-analysis aim at elucidating the heterogeneity in beneficial effects of antioxidant supplementation in obese adults by exploring the differential effects of antioxidant supplementation on basic indicators of obesity, lipid metabolism, systemic antioxidant capacity, inflammatory biomarkers, and liver function.

Methods

The inclusion criteria specified randomized controlled trials with antioxidant intervention for adults (mean body mass index (BMI) > 30), from inception to Aug. 8, 2021, in the PubMed, Embase, The Cochrane Library, Web of Science, and Scopus databases. Meta-analysis and publication bias were performed using RevMan 5.4 software. Stata16 software was used to detect publication bias with Egger's and Begg's methods being mainly used. The data of basic indicators of obesity, lipid metabolism index, oxidative stress index, inflammatory biomarkers, and liver function index were collected to analyze the beneficial effects of antioxidant supplementation in obese patients.

Results

A total of 30 studies were included in this study with a sample of 845 obese patients from the antioxidant supplementation group and 766 obese patients from the placebo control group. The meta-analysis showed that obese patients with antioxidant supplementation had lower BMI (mean difference (MD): − 0.44 [95%confidence interval (CI): − 0.84, −0.04], p = 0.03), waist circumference (MD : −0.78 [95%CI:−1.45, −0.11], p = 0.02), fasting blood glucose (FBG) level (standardized mean difference (SMD): − 4.92 [95%CI:−6.87, −2.98], p < 0.001) and homeostasis model assessment of insulin resistance (MD : −0.45 [95%CI:−0.61, −0.3], p < 0.001) when compared to the placebo group. Obese patients on antioxidant supplementation had lower levels of total cholesterol (SMD : −0.43 [95%CI:−0.84, −0.02], p = 0.04), triglycerides (SMD : −0.17 [95%CI:−0.31, −0.04], p = 0.01), low-density lipoprotein (SMD : −0.15 [95%CI:−0.29, −0.01], p = 0.03), malondialdehyde (SMD : −1.67 [95%CI:−2.69, −0.65], p = 0.001), and tumor necrosis factor-alpha (SMD : −0.29 [95%CI:−0.56, −0.02], p = 0.03), respectively, when compared to the placebo group. In addition, obese patients with antioxidant supplementation had higher levels of high-density lipoprotein (SMD : 0.25 [95%CI : 0.03, 0.46], p = 0.03) and superoxide dismutase (SMD : 1.09 [95%CI : 0.52, 1.65], p < 0.001) when compared to the placebo group. Antioxidant supplementation had no effects on other analyzed parameters including waist–hip ratio, leptin, fat mass, interleukin-6, C-reactive protein, alanine transaminase, and aspartate transaminase in obese patients.

Conclusion

The meta-analysis results indicated that antioxidant supplementation exerted potential beneficial effects in obese patients by regulating FBG, oxidative stress, and inflammation, whilst more high-quality studies are required to confirm these effects. The present study may provide important insights for the treatment of clinical obesity and obesity-associated complications.

Markers of Oxidative Stress in Obstetrics and Gynaecology-A Systematic Literature Review

Oxidative stress has been implicated in many diseases, including reproductive and pregnancy disorders, from subfertility to maternal vascular disease or preterm labour. There is, however, discrepancy within the standardized markers of oxidative stress in obstetrics and gynaecology in clinical studies. This review aims to present the scope of markers used between 2012 and 2022 to describe oxidative stress with regard to reproduction, pregnancy, and pregnancy-related issues. Despite the abundance of evidence, there is no consensus on the set of standardised markers of oxidative stress which poses a challenge to achieve universal consensus in order to appropriately triangulate the results.

Immunonutrients involved in the regulation of the inflammatory and oxidative processes: implication for gamete competence

Purpose

The purpose of this umbrella review is to bring together the most recent reviews concerning the role of immunonutrients for male and female infertility.

Methods

Regarding immunonutrients and fertility, the authors have analyzed reviews, systematic reviews, and meta-analyses published between 2011 and June 2021. All reviews on animal or in vitro studies were excluded. Relevant keywords to term micronutrients were analyzed alone or in association with other terms such as “gamete competence,” “male OR female fertility,” “male OR female infertility,” “fertile, “folliculogenesis,” “spermatogenesis,” “immunomodulation,” “immune system,” “oxidative stress.”

Results

The primary research has included 108 results, and after screening by title, abstract. and not topic-related, 41 studies have been included by full texts. The results show the molecular mechanisms and the immunonutrients related impact on gamete formation, development. and competence. In particular, this review focused on arginine, glutamine, vitamin C, vitamin D, vitamin E, omega-3, selenium, and zinc.

Conclusions

Inflammation and oxidative stress significantly impact human reproduction. For this reason, immunonutrients may play an important role in the treatment of infertile patients. However, due to the lack of consistent clinical trials, their application is limited. Therefore, the development of clinical trials is necessary to define the correct supplementation, in case of deficiency.

Oxidative Stress and Assisted Reproduction: A Comprehensive Review of Its Pathophysiological Role and Strategies for Optimizing Embryo Culture Environment

Oxidative stress (OS) due to an imbalance between reactive oxygen species (ROS) and antioxidants has been established as an important factor that can negatively affect the outcomes of assisted reproductive techniques (ARTs). Excess ROS exert their pathological effects through damage to cellular lipids, organelles, and DNA, alteration of enzymatic function, and apoptosis. ROS can be produced intracellularly, from immature sperm, oocytes, and embryos. Additionally, several external factors may induce high ROS production in the ART setup, including atmospheric oxygen, CO2 incubators, consumables, visible light, temperature, humidity, volatile organic compounds, and culture media additives. Pathological amounts of ROS can also be generated during the cryopreservation-thawing process of gametes or embryos. Generally, these factors can act at any stage during ART, from gamete preparation to embryo development, till the blastocyst stage. In this review, we discuss the in vitro conditions and environmental factors responsible for the induction of OS in an ART setting. In addition, we describe the effects of OS on gametes and embryos. Furthermore, we highlight strategies to ameliorate the impact of OS during the whole human embryo culture period, from gametes to blastocyst stage.

Metabolic Control of Germline Formation and Differentiation in Mammals

BACKGROUND

The germ cell lineage involves dynamic epigenetic changes during its formation and differentiation that are completely different from those of the somatic cell lineage. Metabolites and metabolic pathways have been reported as key factors related to the regulation of epigenetics as cofactors and substrates. However, our knowledge about the metabolic characteristics of germ cells, especially during the fetal stage, and their transition during differentiation is quite limited due to the rarity of the cells. Nevertheless, recent developments in omics technologies have made it possible to extract comprehensive metabolomic features of germ cells.

SUMMARY

In this review, we present the latest researches on the metabolic properties of germ cells in 4 stages: primordial germ cell specification, fetal germ cell differentiation, spermatogenesis, and oogenesis. At every stage, extensive published data has been accumulated on energy metabolism, and it is possible to describe its changes during germ cell differentiation in detail. As pluripotent stem cells differentiate into germ cells, energy metabolism shifts from glycolysis to oxidative phosphorylation; however, in spermatogenesis, glycolytic pathways are also temporarily dominant in spermatogonial stem cells. Although the significance of metabolic pathways other than energy metabolism in germ cell differentiation is largely unknown, the relation of the pentose phosphate pathway and Ser-Gly-one-carbon metabolism with germ cell properties has been suggested at various stages. We further discuss the relationship between these characteristic metabolic pathways and epigenetic regulation during germ cell specification and differentiation. Finally, the relevance of dietary and supplemental interventions on germ cell function and epigenomic regulation is also discussed. Key Messages: Comprehensive elucidation of metabolic features and metabolism-epigenome crosstalk in germ cells is important to reveal how the characteristic metabolic pathways are involved in the germ cell regulation. The accumulation of such insights would lead to suggestions for optimal diets and supplements to maintain reproductive health through modulating metabolic and epigenetic status of germ cells.

Intraovarian Injection of Autologous Platelet-Rich Plasma Improves Therapeutic Approaches in The Patients with Poor Ovarian Response: A Before-After Study

BACKGROUND

Advanced age is associated with a decline in the natural oocytes, low oocyte yield, and also increases the assisted reproductive technology (ART) failure rate, and consequently resulted in a pregnancy rate decrease. Platelet-rich plasma (PRP) is one of the proposed therapeutic strategies for women with poor ovarian response (POR). Because of the autologous source of PRP, the lowest risks of disease transmission, immunogenic and allergic reactions have been expected. This study aimed to evaluate the single-dose intraovarian injection of autologous PRP in poor ovarian reserve.

MATERIALS AND METHODS

We conducted a clinical trial study in the Al-Zahra hospital and Milad Infertility Clinic, Tabriz, Iran (April and May, 2021). A total of thirty-five women with a POR and mean age 40.68 ± 0.34 enrolled in this study. After injection of autologous PRP into the ovaries, the number of oocytes, antral follicles, and level of estradiol, anti-Müllerian hormone (AMH), follicle-stimulating hormone (FSH), luteal hormone (LH), FSH/LH ratio also were evaluated while, these parameters were evaluated before PRP administration.

RESULTS

At the 2-month follow-up, women treated with PRP showed a significant elevation in the number of oocytes (3.68 ± 0.24, P=0.0043) and embryos (3.17 ± 0.14, P=0.0001), as well as in the estradiol levels (404.1 ± 16.76 vs. 237.7 ± 13.14, P=0.0003).

CONCLUSION

Single PRP injection is effective and might be a promising therapeutic approach in the patients with POR to conceive with their own oocytes, although further evidence is required to assess the influence of PRP on the live birth rate.

Essentiality of Trace Elements in Pregnancy, Fertility, and Gynecologic Cancers-A State-of-the-Art Review

Gynecological neoplasms pose a serious threat to women's health. It is estimated that in 2020, there were nearly 1.3 million new cases worldwide, from which almost 50% ended in death. The most commonly diagnosed are cervical and endometrial cancers; when it comes to infertility, it affects ~48.5 million couples worldwide and the number is continually rising. Ageing of the population, environmental factors such as dietary habits, environmental pollutants and increasing prevalence of risk factors may affect the reproductive potential in women. Therefore, in order to identify potential risk factors for these issues, attention has been drawn to trace elements. Trace mineral imbalances can be caused by a variety of causes, starting with hereditary diseases, finishing with an incorrect diet or exposure to polluted air or water. In this review, we aimed to summarize the current knowledge regarding trace elements imbalances in the case of gynecologic cancers as well as female fertility and during pregnancy.

New Therapeutics in Endometriosis: A Review of Hormonal, Non-Hormonal, and Non-Coding RNA Treatments

Endometriosis is defined as endometrial-like tissue outside the uterine cavity. It is a chronic inflammatory estrogen-dependent disease causing pain and infertility in about 10% of women of reproductive age. Treatment nowadays consists of medical and surgical therapies. Medical treatments are based on painkillers and hormonal treatments. To date, none of the medical treatments have been able to cure the disease and symptoms recur as soon as the medication is stopped. The development of new biomedical targets, aiming at the cellular and molecular mechanisms responsible for endometriosis, is needed. This article summarizes the most recent medications under investigation in endometriosis treatment with an emphasis on non-coding RNAs that are emerging as key players in several human diseases, including cancer and endometriosis.

Antioxidants Present in Reproductive Tract Fluids and Their Relevance for Fertility

Nowadays, infertility is classified as a disease of the reproductive system. Although it does not compromise the life of the individual, it can have detrimental effects on the physiological and psychological health of the couple. Male fertility evaluation is mainly focused on the analysis of sperm parameters. However, the ejaculated fluid is also composed of seminal plasma, and the study of this fluid can provide crucial information to help in the assessment of male fertility status. Total antioxidant capacity of the seminal plasma has been positively correlated with the fertility of men. Moreover, evidence highlights to a similar importance as that of female reproductive tract fluid antioxidant capabilities and female fertility. Herein, we describe the functions of seminal plasma and female reproductive tract fluids, as well as their main antioxidant components and their relationships with fertility outcomes. Additionally, this review contains the most up to date information regarding the mechanisms of the interaction between the male and the female reproductive fluids and the importance of proper antioxidant capacity for fertilization.

Potential of Mitochondrial Genome Editing for Human Fertility Health

Mitochondrial DNA (mtDNA) encodes vital proteins and RNAs for the normal functioning of the mitochondria. Mutations in mtDNA leading to mitochondrial dysfunction are relevant to a large spectrum of diseases, including fertility disorders. Since mtDNA undergoes rather complex processes during gametogenesis and fertilization, clarification of the changes and functions of mtDNA and its essential impact on gamete quality and fertility during this process is of great significance. Thanks to the emergence and rapid development of gene editing technology, breakthroughs have been made in mitochondrial genome editing (MGE), offering great potential for the treatment of mtDNA-related diseases. In this review, we summarize the features of mitochondria and their unique genome, emphasizing their inheritance patterns; illustrate the role of mtDNA in gametogenesis and fertilization; and discuss potential therapies based on MGE as well as the outlook in this field.

Preconception lifestyle advice for people with infertility

BACKGROUND

Infertility is a prevalent problem that has significant consequences for individuals, families, and the community. Modifiable lifestyle factors may affect the chance of people with infertility having a baby. However, no guideline is available about what preconception advice should be offered. It is important to determine what preconception advice should be given to people with infertility and to evaluate whether this advice helps them make positive behavioural changes to improve their lifestyle and their chances of conceiving.

OBJECTIVES

To assess the safety and effectiveness of preconception lifestyle advice on fertility outcomes and lifestyle behavioural changes for people with infertility.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Specialised Register of controlled trials, CENTRAL, MEDLINE, Embase, PsycINFO, AMED, CINAHL, trial registers, Google Scholar, and Epistemonikos in January 2021; we checked references and contacted field experts to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), randomised cross-over studies, and cluster-randomised studies that compared at least one form of preconception lifestyle advice with routine care or attention control for people with infertility.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. Primary effectiveness outcomes were live birth and ongoing pregnancy. Primary safety outcomes were adverse events and miscarriage. Secondary outcomes included reported behavioural changes in lifestyle, birth weight, gestational age, clinical pregnancy, time to pregnancy, quality of life, and male factor infertility outcomes. We assessed the overall quality of evidence using GRADE criteria.

MAIN RESULTS

We included in the review seven RCTs involving 2130 participants. Only one RCT included male partners. Three studies compared preconception lifestyle advice on a combination of topics with routine care or attention control. Four studies compared preconception lifestyle advice on one topic (weight, alcohol intake, or smoking) with routine care for women with infertility and specific lifestyle characteristics. The evidence was of low to very low-quality. The main limitations of the included studies were serious risk of bias due to lack of blinding, serious imprecision, and poor reporting of outcome measures. Preconception lifestyle advice on a combination of topics versus routine care or attention control Preconception lifestyle advice on a combination of topics may result in little to no difference in the number of live births (risk ratio (RR) 0.93, 95% confidence interval (CI) 0.79 to 1.10; 1 RCT, 626 participants), but the quality of evidence was low. No studies reported on adverse events or miscarriage. Due to very low-quality evidence, we are uncertain whether preconception lifestyle advice on a combination of topics affects lifestyle behavioural changes: body mass index (BMI) (mean difference (MD) -1.06 kg/m², 95% CI -2.33 to 0.21; 1 RCT, 180 participants), vegetable intake (MD 12.50 grams/d, 95% CI -8.43 to 33.43; 1 RCT, 264 participants), alcohol abstinence in men (RR 1.08, 95% CI 0.74 to 1.58; 1 RCT, 210 participants), or smoking cessation in men (RR 1.01, 95% CI 0.91 to 1.12; 1 RCT, 212 participants). Preconception lifestyle advice on a combination of topics may result in little to no difference in the number of women with adequate folic acid supplement use (RR 0.98, 95% CI 0.95 to 1.01; 2 RCTs, 850 participants; I² = 4%), alcohol abstinence (RR 1.07, 95% CI 0.99 to 1.17; 1 RCT, 607 participants), and smoking cessation (RR 1.01, 95% CI 0.98 to 1.04; 1 RCT, 606 participants), on low quality evidence. No studies reported on other behavioural changes. Preconception lifestyle advice on weight versus routine care Studies on preconception lifestyle advice on weight were identified only in women with infertility and obesity. Compared to routine care, we are uncertain whether preconception lifestyle advice on weight affects the number of live births (RR 0.94, 95% CI 0.62 to 1.43; 2 RCTs, 707 participants; I² = 68%; very low-quality evidence), adverse events including gestational diabetes (RR 0.78, 95% CI 0.48 to 1.26; 1 RCT, 317 participants; very low-quality evidence), hypertension (RR 1.07, 95% CI 0.66 to 1.75; 1 RCT, 317 participants; very low-quality evidence), or miscarriage (RR 1.50, 95% CI 0.95 to 2.37; 1 RCT, 577 participants; very low-quality evidence). Regarding lifestyle behavioural changes for women with infertility and obesity, preconception lifestyle advice on weight may slightly reduce BMI (MD -1.30 kg/m², 95% CI -1.58 to -1.02; 1 RCT, 574 participants; low-quality evidence). Due to very low-quality evidence, we are uncertain whether preconception lifestyle advice affects the percentage of weight loss, vegetable and fruit intake, alcohol abstinence, or physical activity. No studies reported on other behavioural changes. Preconception lifestyle advice on alcohol intake versus routine care Studies on preconception lifestyle advice on alcohol intake were identified only in at-risk drinking women with infertility. We are uncertain whether preconception lifestyle advice on alcohol intake affects the number of live births (RR 1.15, 95% CI 0.53 to 2.50; 1 RCT, 37 participants; very low-quality evidence) or miscarriages (RR 1.31, 95% CI 0.21 to 8.34; 1 RCT, 37 participants; very low-quality evidence). One study reported on behavioural changes for alcohol consumption but not as defined in the review methods. No studies reported on adverse events or other behavioural changes. Preconception lifestyle advice on smoking versus routine care Studies on preconception lifestyle advice on smoking were identified only in smoking women with infertility. No studies reported on live birth, ongoing pregnancy, adverse events, or miscarriage. One study reported on behavioural changes for smoking but not as defined in the review methods.

AUTHORS' CONCLUSIONS

Low-quality evidence suggests that preconception lifestyle advice on a combination of topics may result in little to no difference in the number of live births. Evidence was insufficient to allow conclusions on the effects of preconception lifestyle advice on adverse events and miscarriage and on safety, as no studies were found that looked at these outcomes, or the studies were of very low quality. This review does not provide clear guidance for clinical practice in this area. However, it does highlight the need for high-quality RCTs to investigate preconception lifestyle advice on a combination of topics and to assess relevant effectiveness and safety outcomes in men and women with infertility.

Low Doses of Resveratrol Protect Human Granulosa Cells from Induced-Oxidative Stress

Resveratrol is a phytoalexin present in plant-derived foods, including grape’s skin, cocoa, and peanuts. Evidence suggests that it has beneficial effects on human health because of its antioxidant properties. However, there is limited knowledge about the part played by resveratrol in ovarian function. In this paper, the influence of resveratrol on granulosa cells (GC) was evaluated. In addition to being the main estradiol producers, GC are in direct contact with the oocyte, playing a fundamental role in its growth and development. The cell line COV434 and human granulosa cells (hGC), obtained from women undergoing assisted reproductive technology (ART), were used. GC were treated with resveratrol (0.001–20 μM) at different times (24–72 h). Low concentrations of this compound suggest a protective role, as they tend to reduce ROS/RNS formation after inducement of stress. On the contrary, high concentrations of resveratrol affect GC viability and steroidogenic function. As it may act as a direct modulator of GC oxidative balance, this work may help to clarify the impact of resveratrol on GC and the usefulness of this antioxidant as adjunct to infertility treatments.

Lower Plasma Melatonin in the Intervertebral Disk Degeneration Patients Was Associated with Increased Proinflammatory Cytokines

Background

Intervertebral disc degeneration (IDD) was considered to be the pathological basis of intervertebral disc herniation (IDH). However, the plasma melatonin in the IDD cases and healthy controls remained unclear.

Methods

In this case–control study, a total of 71 IDD cases and 54 healthy controls were enrolled between April 2020 and August 2020. The diagnostic effect of plasma melatonin for IDD was detected using receiver operating characteristic curve. The correlations between two continuous variables were detected with the Pearson linear analyses.

Results

It was found that lower melatonin concentration was detected in the IDD cases (1.906 ± 1.041 vs 3.072 ± 0.511 pg/mL, P<0.001). Through receiver operating characteristic curve analyses, it was found that plasma melatonin could be used as a diagnostic biomarker for IDD (area under curve=0.808, P<0.001). In advanced correlation analyses, it was found that plasma melatonin concentration was negatively associated with the age, symptom durations, IDD disease severity and proinflammatory factors, including IL-6 and TNF-α concentrations (P<0.05). Comparing with the higher melatonin groups, significantly increased IL-6 (0.601 ± 0.085 vs 0.507 ± 0.167 pg/mL, P=0.028) and TNF-α (3.022 ± 0.286 vs 2.353 ± 0.641, P<0.001) were detected in the patients with lower melatonin concentration.

Conclusion

The plasma melatonin concentration was significantly decreased in the IDD cases and plasma melatonin could be used as a diagnostic biomarker for IDD. Lower plasma melatonin was associated with longer disease durations, elevated disease severity and higher inflammatory cytokines levels in IDD patients.

Embryo and Its Mitochondria

The mitochondria, present in almost all eukaryotic cells, produce energy but also contribute to many other essential cellular functions. One of the unique characteristics of the mitochondria is that they have their own genome, which is only maternally transmitted via highly specific mechanisms that occur during gametogenesis and embryogenesis. The mature oocyte has the highest mitochondrial DNA copy number of any cell. This high mitochondrial mass is directly correlated to the capacity of the oocyte to support the early stages of embryo development in many species. Indeed, the subtle energetic and metabolic modifications that are necessary for each of the key steps of early embryonic development rely heavily on the oocyte’s mitochondrial load and activity. For example, epigenetic reprogramming depends on the metabolic cofactors produced by the mitochondrial metabolism, and the reactive oxygen species derived from the mitochondrial respiratory chain are essential for the regulation of cell signaling in the embryo. All these elements have also led scientists to consider the mitochondria as a potential biomarker of oocyte competence and embryo viability, as well as a key target for future potential therapies. However, more studies are needed to confirm these findings. This review article summarizes the past two decades of research that have led to the current understanding of mitochondrial functions in reproduction

The Impact of Unbalanced Maternal Nutritional Intakes on Oocyte Mitochondrial Activity: Implications for Reproductive Function

Accumulating evidence on the effect of nutrition on reproduction is emerging from both animal and human studies. A healthy dietary pattern and nutrient supplementation, especially during the peri-conceptional period, might be helpful to achieve a live birth, although the mechanisms implicated are not fully understood. The endocrine system and the ooplasmic organelles apparatus, in particular the mitochondria, are clearly key elements during oogenesis and subsequent embryo development, and their proper functioning is associated with nutrition, even beyond maternal aging. Several studies in animal models have reported various adverse effects on mitochondria caused by unbalanced dietary intakes such as high fat diet, high fat high sugar diet, and low protein diet. The alterations produced might include mitochondrial intracellular distribution, content, structure, biogenesis, and functioning. This review summarizes the key role of mitochondria in female reproduction and the effects of different dietary macronutrient compositions on oocyte mitochondrial activity with their possible short-, medium-, and long-term effects.

Qualitative and Quantitative Ovarian and Peripheral Blood Mitochondrial DNA (mtDNA) Alterations: Mechanisms and Implications for Female Fertility

The reduction of female fertility over time is considered as a natural consequence of ovarian aging. The exact mechanism underlying this process is not fully elucidated. However, it is becoming increasingly evident that qualitative and quantitative mitochondrial genome alterations might play a relevant role. The former include mitochondrial DNA (mtDNA) damage caused by oxidative stress, the accumulation of acquired mtDNA mutations, the effects of inherited mtDNA mutations, and alterations in the mitochondrial stress response mechanism. The latter refer to alterations in the oocytes, granuolosa cells, and embryonic cells mtDNA content. The present review aims to investigate the evidence about: (1) the effect of qualitative and quantitative mtDNA alterations on female fertility, paying particular attention to those with a pathophysiology characterized by a relevant role of oxidative stress; (2) the use of oocytes, granulosa cells (GCs), embryonic cells, and peripheral blood cells mtDNA copy number as a female fertility surrogate biomarker; (3) experimental therapies tested to try to subvert the ovarian aging process with particular reference to antioxidant treatments.

Clinical Application of Antioxidants to Improve Human Oocyte Mitochondrial Function: A Review

Mitochondria produce adenosine triphosphate (ATP) while also generating high amounts of reactive oxygen species (ROS) derived from oxygen metabolism. ROS are small but highly reactive molecules that can be detrimental if unregulated. While normally functioning mitochondria produce molecules that counteract ROS production, an imbalance between the amount of ROS produced in the mitochondria and the capacity of the cell to counteract them leads to oxidative stress and ultimately to mitochondrial dysfunction. This dysfunction impairs cellular functions through reduced ATP output and/or increased oxidative stress. Mitochondrial dysfunction may also lead to poor oocyte quality and embryo development, ultimately affecting pregnancy outcomes. Improving mitochondrial function through antioxidant supplementation may enhance reproductive performance. Recent studies suggest that antioxidants may treat infertility by restoring mitochondrial function and promoting mitochondrial biogenesis. However, further randomized, controlled trials are needed to determine their clinical efficacy. In this review, we discuss the use of resveratrol, coenzyme-Q10, melatonin, folic acid, and several vitamins as antioxidant treatments to improve human oocyte and embryo quality, focusing on the mitochondria as their main hypothetical target. However, this mechanism of action has not yet been demonstrated in the human oocyte, which highlights the need for further studies in this field.

Is Melatonin the Cornucopia of the 21st Century?

Melatonin, an indoleamine hormone produced and secreted at night by pinealocytes and extra-pineal cells, plays an important role in timing circadian rhythms (24-h internal clock) and regulating the sleep/wake cycle in humans. However, in recent years melatonin has gained much attention mainly because of its demonstrated powerful lipophilic antioxidant and free radical scavenging action. Melatonin has been proven to be twice as active as vitamin E, believed to be the most effective lipophilic antioxidant. Melatonin-induced signal transduction through melatonin receptors promotes the expression of antioxidant enzymes as well as inflammation-related genes. Melatonin also exerts an immunomodulatory action through the stimulation of high-affinity receptors expressed in immunocompetent cells. Here, we reviewed the efficacy, safety and side effects of melatonin supplementation in treating oxidative stress- and/or inflammation-related disorders, such as obesity, cardiovascular diseases, immune disorders, infectious diseases, cancer, neurodegenerative diseases, as well as osteoporosis and infertility.