Impact of Alcohol Consumption on Male Fertility Potential: A Narrative Review

Transgenerational effects of paternal exposures: the role of germline de novo mutations

Germline de novo mutations (DNMs) refer to spontaneous mutations arising during gametogenesis, resulting in genetic changes within germ cells that are subsequently transmitted to the next generation. While the impact of maternal exposures on germline DNMs has been extensively studied, more recent studies have begun to highlight the increasing importance of the effects of paternal factors. In this review, we have summarized the existing literature on how various exposures experienced by fathers affect the germline DNM burden in their spermatozoa, as well as their consequences for semen analysis parameters, pregnancy outcomes, and offspring health. A growing body of literature supports the conclusion that advanced paternal age (APA) correlates with a higher germline DNM rate in offspring. Furthermore, lifestyle choices, environmental toxins, assisted reproductive techniques (ART), and chemotherapy are associated with the accumulation of paternal DNMs in spermatozoa, with deleterious consequences for pregnancy outcomes and offspring health. Ultimately, our review highlights the clear importance of the germline DNM mode of inheritance, and the current understanding of how this is affected by various paternal factors. In addition, we explore conflicting reports or gaps of knowledge that should be addressed in future research.

Effects of substance exposure on gametes and pre-implantation embryos: a narrative review

Substance use refers to the consumption of drugs that have varying degrees of impact on a persons' physical, mental and emotional well-being. While the adverse health effects of drugs have been extensively documented, further research is needed to understand their impact on fertility. Studies have indicated that substance use affects both the male and female reproductive systems. As substance use is more prevalent among young adults compared with the elderly, it appears that individuals of reproductive age are particularly vulnerable to the reproductive impairments associated with substance use. Although numerous studies have reported detrimental effects of substance use on pregnant women and their foetus during the post-implantation stages, there are limited studies on critical pre-implantation period and gamete stages. In this narrative review, we aimed to focus on the most significant evidence regarding the impact of substances on gametes and pre-implantation embryos.

A systematic review of interventions to improve male knowledge of fertility and fertility-related risk factors

Male infertility is a global health concern. The effectiveness of interventions developed to improve males' knowledge of fertility regulation and fertility-related risk factors remains unclear. This systematic review aimed to synthesize and evaluate the evidence for these interventions. Four databases were searched from inception to June 2023. Eligible studies examined interventions to increase fertility knowledge among presumed fertile males aged ≥16 years of age. Conference abstracts, protocols and studies without sex-disaggregated results for males were excluded. A narrative synthesis without meta-analysis was performed. A total of 4884 records were identified. Five studies (reported in six publications), all conducted in high-income countries, were included. Two were randomized control trials, and three were experimental studies. Interventions were delivered in person by a health professional (n = 3), online and via a mobile app. All studies showed a significant improvement in knowledge of fertility or fertility-related risk factors from baseline to follow-up. The largest improvement was observed for secondary and vocational students. A moderate, long-term retainment of knowledge was observed at two-year follow-up in one study. Available evidence suggests interventions to improve males' fertility knowledge are effective, particularly for younger, less educated males.

Understanding the Role of Alcohol in Metabolic Dysfunction and Male Infertility

Purpose: Over the past 40-50 years, demographic shifts and the obesity epidemic have coincided with significant changes in lifestyle habits, including a rise in excessive alcohol consumption. This increase in alcohol intake is a major public health concern due to its far-reaching effects on human health, particularly on metabolic processes and male reproductive function. This narrative review focuses on the role of alcohol consumption in altering metabolism and impairing testicular function, emphasizing the potential damage associated with both acute and chronic alcohol intake. Conclusion: Chronic alcohol consumption has been shown to disrupt liver function, impair lipid metabolism, and dysregulate blood glucose levels, contributing to the development of obesity, metabolic syndrome, and related systemic diseases. In terms of male reproductive health, alcohol can significantly affect testicular function by lowering testosterone levels, reducing sperm quality, and impairing overall fertility. The extent of these effects varies, depending on the frequency, duration, and intensity of alcohol use, with chronic and abusive consumption posing greater risks. The complexity of alcohol's impact is further compounded by individual variability and the interaction with other lifestyle factors such as diet, stress, and physical activity. Despite growing concern, research on alcohol's effects remains inconclusive, with significant discrepancies across studies regarding the definition and reporting of alcohol consumption. These inconsistencies highlight the need for more rigorous, methodologically sound research to better understand how alcohol consumption influences metabolic and reproductive health. Ultimately, a clearer understanding is essential for developing targeted public health interventions, particularly in light of rising alcohol use, demographic changes, and the ongoing obesity crisis.

L-carnitine combined with traditional Chinese medicine for male infertility: A systematic review and meta-analysis

Background

Fertility rates are declining globally, and male infertility is increasingly recognized as a significant challenge. This study aims to present the latest findings on the effectiveness and safety of combining traditional Chinese medicine (TCM) with L-carnitine (LC) for treating male infertility.

Methods

We searched 8 databases. Randomized controlled trials of TCM combined with LC therapy versus LC alone in the treatment of male infertility. The outcome included: pregnancy rate, sperm motility, concentration, volume, viability and liquefaction time. Subgroup analyses were also performed according to type of TCM, type of dosage form, and different TCM treatments, and the source of the high heterogeneity was explored. The study is registered on PROSPERO (CRD42023421497).

Results

1129 subjects from 12 of the 1833 eligible studies fulfilled the criteria. Compared with LC treatment alone, the combination of TCM and LC significantly improved pregnancy rate [RR = 1.65, 95 % CI (1.37-2.00)], grade (a+b) sperm motility [SMD = 1.56, 95 % CI (1.12, 2.01)], grade (a) sperm motility [SMD = 1.04, 95 % CI (0.69, 1.38)], sperm concentration [SMD = 1.39, 95 % CI (0.91, 1.86)], and sperm viability [SMD = 1.72, 95 % CI (0.83, 2.60)]. Subgroup analyses indicated that Compound Xuanju Capsule and Yougui Capsule demonstrated better efficacy. And the decoction and not-decoction each had their own advantages.

Conclusions

The combination of TCM with LC can have a dual effect: increasing pregnancy rates and sperm quality. Therefore, this combination is a recommended therapeutic strategy and a more appropriate type of TCM can be selected according to the patient's own characteristics.

Empirical Treatments for Male Infertility: A Focus on Lifestyle Modifications and Medicines

BACKGROUND/OBJECTIVES

Male infertility is a prevalent issue impacting numerous couples worldwide. This review aims to evaluate the effectiveness of empirical therapies for male infertility, focusing on both lifestyle modifications and medical treatments. This study provides a comprehensive overview of interventions aimed at improving male fertility outcomes.

METHODS

A thorough review of the existing literature was conducted, encompassing studies on lifestyle changes such as dietary changes, smoking cessation, alcohol moderation, and exercise. Additionally, medical treatments including selective estrogen receptor modulators, gonadotropins, aromatase inhibitors, phosphodiesterase-5 inhibitors, antioxidants, dopamine agonists, kallikrein, indomethacin, low-dose corticosteroids, alpha-blockers, and nitric oxide donors were evaluated. The study population included males diagnosed with infertility, focusing on various underlying causes.

RESULTS

Lifestyle modifications were found to have a positive impact on sperm quality. Evidence shows that a healthy diet, smoking cessation, moderate alcohol consumption, and regular exercise improve fertility outcomes. Medical treatments demonstrated significant improvements in sperm production and quality. Selective estrogen receptor modulators and gonadotropins enhanced sperm parameters. Aromatase inhibitors and phosphodiesterase-5 inhibitors specifically improved sperm motility and increased pregnancy rates. Antioxidants, such as vitamins E and C and coenzyme Q10, reduced oxidative stress and enhanced sperm counts, motility, and morphology. Dopamine agonists, particularly cabergoline, normalized prolactin levels and improved fertility outcomes. Kallikrein therapy improved sperm parameters and increased pregnancy rates. Indomethacin treatment was associated with increased sperm concentrations and motility. Low-dose corticosteroids and alpha-blockers showed variable results, and nitric oxide donors like L-arginine enhanced sperm counts and motility.

CONCLUSIONS

Empirical therapies, including lifestyle modifications and medical treatments, significantly enhance sperm quality and reproductive potential. These integrated approaches are essential in improving fertility outcomes in males. However, further extensive randomized trials are necessary to definitively establish the most effective treatments.

The relationship between cardiometabolic index and infertility in American adults: a population-based study

Background

Infertility is a fertility disorder caused by various factors, with lipid metabolism playing a crucial role in its development. The cardiometabolic index (CMI), which combines blood lipids (TG/HDL-C) and obesity-related parameters (WHtR), is a new quantitative indicator. This study used NHANES data to investigate the relationship between CMI and the incidence of infertility.

Methods

We utilized data from women who took part in the National Health and Nutrition Examination Survey (NHANES) from 2015 to March 2020 to calculate the CMI index. Subsequently, we used multivariate logistic regression, smooth curve fitting, and subgroup analysis to investigate the relationship between the CMI index and infertility.

Results

The logistic regression model revealed a significant positive correlation between the CMI index and infertility, even after adjusting for all confounding variables (OR=3.23, 95%CI: 1.55-6.73, p=0.0017). This association remained consistent across all subgroups (p>0.05 for all interactions). Smooth curve fitting demonstrated a positive nonlinear relationship between CMI and infertility. However, the CMI index had limited diagnostic power for infertility (AUC=0.60, 95%CI: 0.56-0.65). However, the CMI-BMI index combined with BMI had good predictive performance (AUC=0.722, 95%CI: 0.676-0.767).

Conclusion

The CMI index shows a positive correlation with infertility, but its diagnostic value is restricted. The combination with BMI has good diagnostic value. Further investigation is required to determine the effectiveness of the CMI index as an early indicator of infertility.

Male Fertility in Spondyloarthritis: from Clinical Issues to Cytokines Milieu. A Narrative Review

PURPOSEOF REVIEW

Male fertility is an emergent issue that should be considered in clinical practice, when dealing with chronic inflammatory diseases in young men. As it is known, the chronic inflammation is the main pathophysiologic mechanism in some rheumatological conditions such as spondyloarthritis (SpA), Ankylosing Spondylitis (AS) and Psoriatic Arthritis (PsA). Therefore, it is paramount to be aware if these diseases could impair male fertility, both due to the inflammation or to the treatments needed: we reviewed the literature on the most relevant and recent evidence on male fertility in patients affected by SpA, AS and PsA.

RECENT FINDINGS

Rheumatological inflammatory diseases (included SpA, AS and PsA) could impair the family planning in man life, especially when diagnosed at young age. Moreover, focusing on sperm quality, it seems that a link between sperm quality impairment and a higher disease activity exist. Focusing on therapies, Tumor Necrosis Factor inhibitors showed a safety profile on human male fertility in clinical studies. Recently, a prospective study and two double-blind placebo-controlled trials assessed the impact of methotrexate and Filgotinib on semen parameters, respectively, showing a safety profile of these drugs on human semen quality. However, there are no clinical data on the impact of Interleukin (IL)17 inhibitors(i), IL12-23i and IL23i. Concerning male fertility in SpA, AS and PsA, an unmet clinical need is still present and new studies are needed to understand the association between these diseases and male fertility, and the implication of the therapies used for these diseases. This narrative review provides an overview of the available data on male fertility in patients affected by SpA, AS and PsA.

Influence of substance use on male reproductive health and offspring outcomes

The prevalence of substance use globally is rising and is highest among men of reproductive age. In Africa, and South and Central America, cannabis use disorder is most prevalent and in Eastern and South-Eastern Europe, Central America, Canada and the USA, opioid use disorder predominates. Substance use might be contributing to the ongoing global decline in male fertility, and emerging evidence has linked paternal substance use with short-term and long-term adverse effects on offspring development and outcomes. This trend is concerning given that substance use is increasing, including during the COVID-19 pandemic. Preclinical studies have shown that male preconception substance use can influence offspring brain development and neurobehaviour through epigenetic mechanisms. Additionally, human studies investigating paternal health behaviours during the prenatal period suggest that paternal tobacco, opioid, cannabis and alcohol use is associated with reduced offspring mental health, in particular hyperactivity and attention-deficit hyperactivity disorder. The potential effects of paternal substance use are areas in which to focus public health efforts and health-care provider counselling of couples or individuals interested in conceiving.

Male infertility risk and plasma lipidome: a Mendelian randomization study

Background

In recent years, the decline in sperm quality in men has become a global trend. There is a close relationship between sperm quality and pregnancy outcome. There is a large body of literature supporting the role of plasma lipidome in male infertility, while the complex mechanisms between them and male infertility are still less clear. Systematic study of the causal relationship between plasma lipidome and MI can help to provide new therapeutic ideas and targets for male infertility.

Methods

In this study, we used a two-sample Mendelian randomization analysis based on Genome-wide association studies pooled data of 179 causal relationships between plasma lipidome and male infertility. We used employed the inverse variance weighted method as the main analysis to assess causality between exposure and outcome, in addition to MR-Egger, Weighted median as complementary methods, and tests for multiplicity and heterogeneity.

Results

We identified 13 plasma lipidome comprising 4 types of plasma lipidome that were associated with male infertility. Among these, 9 plasma lipidome were found to be protective factors, while 4 were risk factors. Notably, the largest proportion of these plasma lipidome were triglyceride types, with Sphingomyelin (d40:1) exhibiting the strongest association with male infertility.

Conclusion

These findings contribute to the current better understanding of male infertility and provide new perspectives on the underlying etiology of male infertility as well as prevention and treatment strategies. In addition, clinical trial validation is needed to assess the potential of these plasma lipidome as biomarkers.

Oxidative Stress and Erectile Dysfunction: Pathophysiology, Impacts, and Potential Treatments

Erectile dysfunction (ED) is a prevalent condition affecting men's sexual health, with oxidative stress (OS) having recently been identified as a significant contributing causative factor. This narrative review aims to elucidate the role of OS in the pathophysiology of ED, focusing on impact, mechanisms, and potential therapeutic interventions. Key findings indicate that OS disrupts endothelial function and nitric oxide (NO) signaling, crucial for erectile function. Various sources of reactive oxygen species (ROS) and their detrimental effects on penile tissue are discussed, including aging, diabetes mellitus, hypertension, hyperlipidemia, smoking, obesity, alcohol consumption, psychological stress, hyperhomocysteinemia, chronic kidney disease, and sickle cell disease. Major sources of ROS, such as NADPH oxidase, xanthine oxidase, uncoupled endothelial NO synthase (eNOS), and mitochondrial electron transport, are identified. NO is scavenged by these ROS, leading to endothelial dysfunction characterized by reduced NO availability, impaired vasodilation, increased vascular tone, and inflammation. This ultimately results in ED due to decreased blood flow to penile tissue and the inability to achieve or maintain an erection. Furthermore, ROS impact the transmission of nitrergic neurotransmitters by causing the death of nitrergic neurons and reducing the signaling of neuronal NO synthase (nNOS), exacerbating ED. Therapeutic approaches targeting OS, including antioxidants and lifestyle modifications, show promise in ameliorating ED symptoms. The review underscores the need for further research to develop effective treatments, emphasizing the interplay between OS and vascular health in ED. Integrating pharmacological and non-pharmacological strategies could enhance clinical outcomes for ED patients, advocating for OS management in ED treatment protocols to improve patient quality of life.

Uncovering the impact of alcohol on internal organs and reproductive health: Exploring TLR4/NF-kB and CYP2E1/ROS/Nrf2 pathways

This review delves into the detrimental impact of alcohol consumption on internal organs and reproductive health, elucidating the underlying mechanisms involving the Toll-like receptor 4 (TLR4)/Nuclear factor kappa light chain enhancer of activated B cells (NF-kB) pathway and the Cytochrome P450 2E1 (CYP2E1)/reactive oxygen species (ROS)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathways. The TLR4/NF-kB pathway, crucial for inflammatory and immune responses, triggers the production of pro-inflammatory agents and type-1 interferon, disrupting the balance between inflammatory and antioxidant responses when tissues are chronically exposed to alcohol. Alcohol-induced dysbiosis in gut microbes heightens gut wall permeability to pathogen-associated molecular patterns (PAMPs), leading to liver cell infection and subsequent inflammation. Concurrently, CYP2E1-mediated alcohol metabolism generates ROS, causing oxidative stress and damaging cells, lipids, proteins, and deoxyribonucleic acid (DNA). To counteract this inflammatory imbalance, Nrf2 regulates gene expression, inhibiting inflammatory progression and promoting antioxidant responses. Excessive alcohol intake results in elevated liver enzymes (ADH, CYP2E1, and catalase), ROS, NADH, acetaldehyde, and acetate, leading to damage in vital organs such as the heart, brain, and lungs. Moreover, alcohol negatively affects reproductive health by inhibiting the hypothalamic-pituitary-gonadal axis, causing infertility in both men and women. These findings underscore the profound health concerns associated with alcohol-induced damage, emphasizing the need for public awareness regarding the intricate interplay between immune responses and the multi-organ impacts of alcohol consumption.

Analysis of determinants of infertility among women at <i>in vitro</i> fertilization clinic in Surabaya

In social life and global health, infertility is common. History of abdominal surgery, body mass index (BMI), endometriosis, menstrual history, and polycystic ovarian syndrome (PCOS) have not been fully explained as female infertility factors. This study examined infertility causes at ASHA in vitro fertilization Primasatya Husada Citra (PHC) Hospital Surabaya. This quantitative study was cross-sectional. In May-July 2023, 82 childbearing-age women with infertility issues visited the hospital and completed questionnaires. Description and analysis were performed using the Wilcoxon rank test to evaluate menstrual history, BMI, PCOS, endometriosis, and abdominal surgery history in relation to infertility. Infertility was statistically associated with abdominal surgery history (P=0.008), BMI (P=0.000), endometriosis diagnosis (P=0.000), and PCOS (P=0.000). Women with abdominal surgery, endometriosis, and PCOS had significant infertility. Women’s infertility can be caused by ovulation disorders, tubal and pelvic disorders, or uterine disorders, but one-third of cases are unexplained. Infertility treatment may benefit from addressing abdominal surgery history, BMI, endometriosis, and PCOS. Early intervention and targeted care based on these determinants may improve fertility outcomes and reduce unexplained infertility.

Paternal Preconceptional Alcohol Use Disorder With the Offspring's Mortality Risk

INTRODUCTION

Paternal preconceptional alcohol use may contribute to early pregnancy loss. However, the link between paternal preconceptional alcohol use disorder and long-term offspring's mortality risk remains unclear. This study examined the association of paternal preconceptional alcohol use disorder and recency of diagnosis with offspring's mortality and further stratified the mortality after the first year of birth by age.

METHODS

This is a nationwide cohort study with 1,973,174 Danish births (1980-2012), with follow-up from birth until death; emigration; or December 31, 2016. Paternal conceptional alcohol use disorder was identified from Danish National Patient Register and Prescription Registry, categorizing recency of diagnosis into <1 year, 1 to <4 years, 4 to <8 years, and ≥8 years. Logistic regression estimated the ORs and 95% CIs for offspring mortality risk. All data were analyzed in 2023.

RESULTS

Paternal preconceptional alcohol use disorder was associated with a 28% increased mortality after 1 year of birth (95% CI=1.09, 1.51), 23% increased infant mortality (95% CI=1.07, 1.42), and 23% increased odds of stillbirth (95% CI=1.06, 1.43). Paternal alcohol use disorder diagnosed <1 year before conception was associated with an 85%-111% increased risk of mortality in offspring aged 15-40 years. More recent alcohol use disorder diagnosis (i.e., 1 year before conception) had a higher risks of death from infectious and circulatory diseases in offsprings.

CONCLUSIONS

Offspring of fathers with alcohol use disorder before conception had higher mortality risk from birth to early adulthood, especially when alcohol use disorder diagnosis is close to conception. Current awareness regarding paternal preconceptional alcohol dependence use is insufficient. Promoting alcohol dependence avoidance, including educating men on the impact of alcohol on child health during prepregnancy examination, may help reduce or prevent long-term offspring mortality.

Alterations in sperm RNAs persist after alcohol cessation and correlate with epididymal mitochondrial dysfunction

BACKGROUND

Chronic preconception paternal alcohol use adversely modifies the sperm epigenome, inducing fetoplacental and craniofacial growth defects in the offspring of exposed males. A crucial outstanding question in the field of paternal epigenetic inheritance concerns the resilience of the male germline and its capacity to recover and correct sperm-inherited epigenetic errors after stressor withdrawal.

OBJECTIVES

We set out to determine if measures of the sperm-inherited epigenetic program revert to match the control treatment 1 month after withdrawing the daily alcohol treatments.

MATERIALS AND METHODS

Using a voluntary access model, we exposed C57BL/6J males to 6% or 10% alcohol for 10 weeks, withdrew the alcohol treatments for 4 weeks, and used RNA sequencing to examine gene expression patterns in the caput section of the epididymis. We then compared the abundance of sperm small RNA species between treatments.

RESULTS

In the caput section of the epididymis, chronic alcohol exposure induced changes in the transcriptional control of genetic pathways related to the mitochondrial function, oxidative phosphorylation, and the generalized stress response (EIF2 signaling). Subsequent analysis identified region-specific, alcohol-induced changes in mitochondrial DNA copy number across the epididymis, which correlated with increases in the mitochondrial DNA content of alcohol-exposed sperm. Notably, in the corpus section of the epididymis, increases in mitochondrial DNA copy number persisted 1 month after alcohol cessation. Analysis of sperm noncoding RNAs between control and alcohol-exposed males 1 month after alcohol withdrawal revealed a ∼100-fold increase in mir-196a, a microRNA induced as part of the nuclear factor erythroid 2-related factor 2 (Nrf2)-driven cellular antioxidant response.

DISCUSSION AND CONCLUSION

Our data reveal that alcohol-induced epididymal mitochondrial dysfunction and differences in sperm noncoding RNA content persist after alcohol withdrawal. Further, differences in mir-196a and sperm mitochondrial DNA copy number may serve as viable biomarkers of adverse alterations in the sperm-inherited epigenetic program.

Associations between dietary macronutrient quality and asthenozoospermia risk: a hospital-based case-control study

Background & aims: Macronutrients are the main part of the human diet and can affect multiple health outcomes. Nevertheless, associations between dietary macronutrient quality and asthenozoospermia risk have not been reported to date. Thus, this study aimed to be the first to explore the associations between macronutrient quality and asthenozoospermia risk using the novel multidimensional macronutrient quality index (MQI). Methods: A case-control study was conducted at infertility clinics of Shengjing Hospital of China Medical University during June and December 2020, including 552 asthenozoospermia cases and 585 normozoospermia controls. Data on diet were collected using a validated food frequency questionnaire. MQI was estimated according to the carbohydrate quality index (CQI), fat quality index (FQI), and protein quality index (PQI). Binary logistic regression models were performed to calculate the odds ratio (OR) with a 95% confidence interval (CI). Subgroup and interaction analyses were performed based on age, body mass index, physical activity, smoking, drinking, and education level. Dose-response relationships were evaluated by restricted cubic splines. Sensitivity analyses were performed in two ways. First, participants with a dietary change were excluded to lower potential reverse causation. Then, we used the healthy plate protein source quality index instead of PQI to redefine MQI. Results: No statistically significant association was observed between dietary MQI and asthenozoospermia risk (OR = 1.24, 95% CI: 0.88-1.73). The sub-indices of MQI, CQI, FQI, and PQI, failed to be identified as having a statistically significant association with asthenozoospermia risk (OR = 1.35, 95% CI: 0.92-1.97 for CQI; OR = 1.13, 95% CI: 0.84-1.53 for FQI; OR = 1.28, 95% CI: 0.92-1.78 for PQI). However, CQI showed a positive association with the risk of asthenozoospermia among non-drinkers (Ptrend < 0.05) and highly educated participants (OR = 1.82, 95% CI: 1.13-2.94; Ptrend < 0.05). Additionally, there was a multiplicative interaction between CQI and education level for asthenozoospermia risk (P < 0.05). Conclusions: Our findings demonstrated no association of MQI and its sub-indices with asthenozoospermia risk except for CQI. Although our findings are mostly non-significant, they contribute novel knowledge to this research field and lay the foundation for future studies.

Inter- and trans-generational impacts of environmental exposures on the germline resolved at the single-cell level

Reproduction is a remarkably intricate process involving the interaction of multiple cell types and organ systems unfolding over long periods of time and that culminates with the production of gametes. The initiation of germ cell development takes place during embryogenesis but only completes decades later in humans. The complexity inherent to reproduction and its study has long hampered our ability to decipher how environmental agents disrupt this process. Single-cell approaches provide an opportunity for a deeper understanding of the action of toxicants on germline function and analyze how the response to their exposure is differentially distributed across tissues and cell types. In addition to single-cell RNA sequencing, other single-cell or nucleus level approaches such as ATAC-sequencing and multi-omics have expanded the strategies that can be implemented in reproductive toxicological studies to include epigenomic and the nuclear transcriptomic data. Here we will discuss the current state of single-cell technologies and how they can best be utilized to advance reproductive toxicological studies. We will then discuss case studies in two model organisms (Caenorhabditis elegans and mouse) studying different environmental exposures (alcohol and e-cigarettes respectively) to highlight the value of single-cell and single-nucleus approaches for reproductive biology and reproductive toxicology.

Association Between Triglyceride Glucose Index and Infertility in Reproductive-Aged Women: A Cross-Sectional Study

Purpose

In recent years, female infertility has become a research hotspot in the field of health management, and its cause may be related to insulin resistance (IR). We used a novel and practical IR indicator, the TyG index to explore its association with infertility.

Patients and Methods

We calculated the TyG index using data from adult women who participated in the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2018. Then, we used multivariate logistic regression, smooth curve fitting, and subgroup analysis to examine the association between the TyG index and infertility in women.

Results

Logistic regression models showed a positive correlation between the TyG index and infertility, which remained significant even after adjusting for all confounders (OR=1.51,95% CI:1.14-2.00, p=0.005). This association was consistent in all subgroups (age, education level, marital status, BMI, smoking, alcohol consumption, hypertension, diabetes, pelvic inflammatory disease/PID treatment, and menstrual regularity in the past 12 months) (p>0.05 for all interactions). However, the diagnostic power of the TyG index for infertility was limited (AUC=0.56, 95% CI: 0.52-0.61).

Conclusion

The TyG index is positively correlated with infertility, but its diagnostic value is limited. Further research is needed on the TyG index as an early predictor of infertility.

Assessing the influence of preconception diet on male fertility: a systematic scoping review

BACKGROUND

The last decade has seen increased research on the relationship between diet and male fertility, but there are no clearly defined nutritional recommendations for men in the preconception period to support clinical fertility outcomes.

OBJECTIVE AND RATIONALE

The purpose of this scoping review is to examine the extent and range of research undertaken to evaluate the effect(s) of diet in the preconception period on male clinical fertility and reproductive outcomes.

SEARCH METHODS

Four electronic databases (MEDLINE and EMBASE via Ovid, CAB Direct, and CINAHL via EBSCO) were searched from inception to July 2023 for randomized controlled trials (RCTs) and observational studies (prospective/retrospective, case-control, and cross-sectional). Intervention studies in male participants or couples aiming to achieve dietary or nutritional change, or non-intervention studies examining dietary or nutritional components (whole diets, dietary patterns, food groups or individual foods) in the preconception period were included. Controls were defined as any comparison group for RCTs, and any/no comparison for observational studies. Primary outcomes of interest included the effect(s) of male preconception diet on clinical outcomes such as conception (natural or via ART), pregnancy rates and live birth rates. Secondary outcomes included time to conception and sperm parameters.

OUTCOMES

A total of 37 studies were eligible, including one RCT and 36 observational studies (prospective, cross-sectional, and case-control studies; four studies in non-ART populations) published between 2008 and 2023. Eight reported clinical outcomes, 26 reported on secondary outcomes, and three reported on both. The RCT did not assess clinical outcomes but found that tomato juice may benefit sperm motility. In observational studies, some evidence suggested that increasing fish or reducing sugar-sweetened beverages, processed meat or total fat may improve fecundability. Evidence for other clinical outcomes, such as pregnancy rates or live birth rates, showed no relationship with cereals, soy and dairy, and inconsistent relationships with consuming red meat or a 'healthy diet' pattern. For improved sperm parameters, limited evidence supported increasing fish, fats/fatty acids, carbohydrates and dairy, and reducing processed meat, while the evidence for fruits, vegetables, cereals, legumes, eggs, red meat and protein was inconsistent. Healthy diet patterns in general were shown to improve sperm health.

WIDER IMPLICATIONS

Specific dietary recommendations for improving male fertility are precluded by the lack of reporting on clinical pregnancy outcomes, heterogeneity of the available literature and the paucity of RCTs to determine causation or to rule out reverse causation. There may be some benefit from increasing fish, adopting a healthy dietary pattern, and reducing consumption of sugar-sweetened beverages and processed meat, but it is unclear whether these benefits extend beyond sperm parameters to improve clinical fertility. More studies exploring whole diets rather than singular foods or nutritional components in the context of male fertility are encouraged, particularly by means of RCTs where feasible. Further assessment of core fertility outcomes is warranted and requires careful planning in high-quality prospective studies and RCTs. These studies can lay the groundwork for targeted dietary guidelines and enhance the prospects of successful fertility outcomes for men in the preconception period. Systematic search of preconception diet suggests that increasing fish and reducing sugary drinks, processed meats and total fat may improve male fertility, while consuming healthy diets, fish, fats/fatty acids, carbohydrates and dairy and reducing processed meat can improve sperm health.

Oxidative Stress Biomarkers in Male Infertility: Established Methodologies and Future Perspectives

Male fertility can be affected by oxidative stress (OS), which occurs when an imbalance between the production of reactive oxygen species (ROS) and the body's ability to neutralize them arises. OS can damage cells and influence sperm production. High levels of lipid peroxidation have been linked to reduced sperm motility and decreased fertilization ability. This literature review discusses the most commonly used biomarkers to measure sperm damage caused by ROS, such as the high level of OS in seminal plasma as an indicator of imbalance in antioxidant activity. The investigated biomarkers include 8-hydroxy-2-deoxyguanosine acid (8-OHdG), a marker of DNA damage caused by ROS, and F2 isoprostanoids (8-isoprostanes) produced by lipid peroxidation. Furthermore, this review focuses on recent methodologies including the NGS polymorphisms and differentially expressed gene (DEG) analysis, as well as the epigenetic mechanisms linked to ROS during spermatogenesis along with new methodologies developed to evaluate OS biomarkers. Finally, this review addresses a valuable insight into the mechanisms of male infertility provided by these advances and how they have led to new treatment possibilities. Overall, the use of biomarkers to evaluate OS in male infertility has supplied innovative diagnostic and therapeutic approaches, enhancing our understanding of male infertility mechanisms.

Changes in environmental exposures over decades may influence the genetic architecture of severe spermatogenic failure

STUDY QUESTION

Do the genetic determinants of idiopathic severe spermatogenic failure (SPGF) differ between generations?

SUMMARY ANSWER

Our data support that the genetic component of idiopathic SPGF is impacted by dynamic changes in environmental exposures over decades.

WHAT IS KNOWN ALREADY

The idiopathic form of SPGF has a multifactorial etiology wherein an interaction between genetic, epigenetic, and environmental factors leads to the disease onset and progression. At the genetic level, genome-wide association studies (GWASs) allow the analysis of millions of genetic variants across the genome in a hypothesis-free manner, as a valuable tool for identifying susceptibility risk loci. However, little is known about the specific role of non-genetic factors and their influence on the genetic determinants in this type of conditions.

STUDY DESIGN, SIZE, DURATION

Case-control genetic association analyses were performed including a total of 912 SPGF cases and 1360 unaffected controls.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All participants had European ancestry (Iberian and German). SPGF cases were diagnosed during the last decade either with idiopathic non-obstructive azoospermia (n = 547) or with idiopathic non-obstructive oligozoospermia (n = 365). Case-control genetic association analyses were performed by logistic regression models considering the generation as a covariate and by in silico functional characterization of the susceptibility genomic regions.

MAIN RESULTS AND THE ROLE OF CHANCE

This analysis revealed 13 novel genetic association signals with SPGF, with eight of them being independent. The observed associations were mostly explained by the interaction between each lead variant and the age-group. Additionally, we established links between these loci and diverse non-genetic factors, such as toxic or dietary habits, respiratory disorders, and autoimmune diseases, which might potentially influence the genetic architecture of idiopathic SPGF.

LARGE SCALE DATA

GWAS data are available from the authors upon reasonable request.

LIMITATIONS, REASONS FOR CAUTION

Additional independent studies involving large cohorts in ethnically diverse populations are warranted to confirm our findings.

WIDER IMPLICATIONS OF THE FINDINGS

Overall, this study proposes an innovative strategy to achieve a more precise understanding of conditions such as SPGF by considering the interactions between a variable exposome through different generations and genetic predisposition to complex diseases.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the "Plan Andaluz de Investigación, Desarrollo e Innovación (PAIDI 2020)" (ref. PY20_00212, P20_00583), the Spanish Ministry of Economy and Competitiveness through the Spanish National Plan for Scientific and Technical Research and Innovation (ref. PID2020-120157RB-I00 funded by MCIN/ AEI/10.13039/501100011033), and the 'Proyectos I+D+i del Programa Operativo FEDER 2020' (ref. B-CTS-584-UGR20). ToxOmics-Centre for Toxicogenomics and Human Health, Genetics, Oncology and Human Toxicology, is also partially supported by the Portuguese Foundation for Science and Technology (Projects: UIDB/00009/2020; UIDP/00009/2020). The authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Exploration of Lactiplantibacillus plantarum P101 ameliorated the alcohol-induced testicular dysfunction based on metabolome analysis

The decline in male sperm quality caused by multiple factors has become a widespread concern. Alcohol excessive consumption is one of the factors that induce testicular dysfunction. Testicular dysfunction caused by alcohol abuse is related to oxidative stress and inflammation. Probiotics can ameliorate alcohol-induced testicular dysfunction. However, the specific mechanism is not explicit. This study aimed to elucidate the underlying mechanism by which Lactiplantibacillus plantarum P101 ameliorates the alcohol-induced testicular dysfunction. The model of alcohol-induced testicular dysfunction in C57B/6 male mice was established according to the National Institute on Alcohol Abuse and Alcoholism, and Lactiplantibacillus plantarum P101 supplementation was orally administered to mice during the experiment. The results showed that Lactiplantibacillus plantarum P101 promoted androgen production, reduced testis inflammation, and improved testis antioxidant capacity, thereby improving sperm quality and sperm motility and ultimately ameliorating alcohol-induced testicular disorder. Three key metabolite pathways and six key metabolites were identified by metabolome analysis.

Decrease in Sperm Parameters in the 21st Century: Obesity, Lifestyle, or Environmental Factors? An Updated Narrative Review

Semen quality represents a compelling factor for fertility, and delineating the normal values has proven difficult. In the last four decades, several authors have reported a noticeable decline in sperm parameters. Also, studies investigating 'time to pregnancy' have shown that fecundity begins to be reduced when sperm numbers decrease below 30 million, even though according to the 6th edition of the WHO manual, the normal value is currently 16 million/mL or 39 million per ejaculate. There exists sufficient data to suggest a decline in sperm counts over time, even though the clear reason for this adverse trend is not well established, but some associations have been hypothesised, such as maternal smoking during pregnancy. Additional potential factors have yet to be fully illustrated but involve poor diet, increased obesity, and exposure to environmental toxins. Moreover, the change in environmental conditions and more common exposure to endocrine-disrupting chemicals (EDCs), such as pesticides and herbicides, as well as bisphenol A, phthalates, polychlorinated biphenyls, and heavy metals, starting from prenatal life and continuing into adulthood, may exhibit probable features explaining the reduction in sperm parameters. Therefore, the main goal of this narrative review is to furnish an overview of the possible effects of exposure to EDCs on testicular function and spermatogenesis and, also, to summarise the evidence regarding a decrease in sperm quality and examine its potential consequences.

Genome-Wide Interaction Study of Dietary Intake and Colorectal Cancer Risk in the UK Biobank

Importance

Candidate gene analysis approaches have shown that colorectal cancer (CRC) risk attributable to diet may differ according to genotype. A genome-wide approach further allows for the exploration of underlying pathways for associations between diet and CRC risk across the genome.

Objectives

To identify genetic variants that modify diet-CRC associations and to further explore the underlying pathways in the cause of CRC.

Design, Setting, and Participants

This nested case-control study used data on White British participants from the prospective cohort UK Biobank. Participants were recruited between March 13, 2006, and October 1, 2010, and data were censored June 25, 2021.

Exposures

The average frequency intake of 11 dietary factors in the year preceding baseline was obtained via a touchscreen questionnaire. After quality control for more than 93 million variants of imputed genetic data, 4 122 345 variants remained.

Main Outcomes and Measures

Colorectal cancer cases were identified according to the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision. Genome-wide interaction analysis was performed to test interactions between dietary factors and variants using a conditional logistic regression model. Summary statistics of interactions at the variant level were used to calculate empirical P values for interactions at gene and gene-set levels in gene-based and gene-set enrichment analyses.

Results

A total of 4686 participants with CRC (mean [SD] age, 60.7 [6.6] years; 2707 men [57.8%]) received a new diagnosis during a median of 12.4 years (IQR, 11.6-13.1 years) of follow-up. Once a case was detected, 3 matched controls were identified, for a total of 14 058 controls (mean [SD] age, 60.4 [6.6] years; 8121 men [57.8%]). A total of 324 variants were identified that interacted with diet consumption at the suggestive threshold (P < 1 × 10-5). In gene-based analysis, aggregation of multiple EPDR1 gene variants was found to interact with fish intake regarding CRC risk. Furthermore, gene-set enrichment analysis found that several sets of protein-coding genes, which were overrepresented with particular functions and pathways, interacted with the consumption of milk (ART), cheese (OR), tea (KRT), and alcohol (PRM and TNP).

Conclusions and Relevance

In this nested case-control study, the risk of CRC associated with fish intake was modified by multiple single-nucleotide polymorphisms of the EPDR1 gene. The findings further suggested possible functions and pathways that might link the consumption of milk, cheese, tea, and alcohol with CRC development.

Potential role of inducible nitric oxide synthase (iNOS) activity in testicular dysfunction following co-administration of alcohol and combination antiretroviral therapy (cART) in diabetic rats: an immunohistochemistry study

Diabetes, alcohol abuse, and combination antiretroviral therapy (cART) use have been reported to cause multi-organ complications via induction of oxidative stress and inflammation. Moreover, these are the most common factors implicated in male reproductive dysfunctions. This study evaluated testicular oxidative stress, inflammation, apoptosis, and germ cell proliferation in diabetic rats receiving alcohol or cART and their combination. Thirty adult male Sprague Dawley rats were divided into five groups, each consisting of six rats; control, diabetic only (DM), diabetic treated with alcohol (DM + A), diabetic treated with cART (DM + cART), and diabetic treated with both alcohol and cART (DM + A + cART). After 90 days of treatment, the rats were terminated, and the testes were extracted and processed for immunohistochemistry analysis for oxidative stress, inflammatory cytokines, apoptosis, and cell proliferation marker. In comparison to the control, oxidative stress markers, inducible nitric oxide synthase (iNOS), malondialdehyde (MDA), and 8-hydroxydeoxyguanosine (8-OHDG) increased significantly in all treated groups. Expression of testicular proinflammatory cytokines, interleukin-1β, and tumor necrosis factor-α was upregulated in all treated groups, but interleukin-6 was upregulated in DM, DM + cART, and DM + A + cART treated groups and was downregulated in the DM + A treated group. All treated animal groups showed an upregulation of apoptotic marker (caspase 3) and a downregulation of proliferation marker (Ki-67). However, Ki-67 staining intensity significantly increased in treated animals compared to the control. These findings suggest that diabetes, alcohol abuse, cART use, and their combination via iNOS activity upregulation can induce inflammation and oxidative stress in testicular tissue, stimulating germ cell apoptosis and proliferation inhibition leading to failure of spermatogenesis.

Environmental and Genetic Traffic in the Journey from Sperm to Offspring

Recent advancements in the understanding of how sperm develop into offspring have shown complex interactions between environmental influences and genetic factors. The past decade, marked by a research surge, has not only highlighted the profound impact of paternal contributions on fertility and reproductive outcomes but also revolutionized our comprehension by unveiling how parental factors sculpt traits in successive generations through mechanisms that extend beyond traditional inheritance patterns. Studies have shown that offspring are more susceptible to environmental factors, especially during critical phases of growth. While these factors are broadly detrimental to health, their effects are especially acute during these periods. Moving beyond the immutable nature of the genome, the epigenetic profile of cells emerges as a dynamic architecture. This flexibility renders it susceptible to environmental disruptions. The primary objective of this review is to shed light on the diverse processes through which environmental agents affect male reproductive capacity. Additionally, it explores the consequences of paternal environmental interactions, demonstrating how interactions can reverberate in the offspring. It encompasses direct genetic changes as well as a broad spectrum of epigenetic adaptations. By consolidating current empirically supported research, it offers an exhaustive perspective on the interwoven trajectories of the environment, genetics, and epigenetics in the elaborate transition from sperm to offspring.

Diet and recreational drug use in relation to male reproductive health

Diet and lifestyle interventions present promising avenues for the improvement of male fertility. Our objective was to review and synthesize the existing observational and experimental studies among humans on the associations of diet and recreational drug use with semen quality and fertility outcomes. The available data on this topic are limited and, at times, conflicting. Nevertheless, on the basis of this review, dietary patterns that are composed of higher intakes of fruits, vegetables, whole grains, nuts, low-fat dairy, and seafood, as well as lower intakes of red and processed meats, sweets, and sugar-sweetened beverages were identified as having the strongest evidence for associations with better sperm quality. However, whether these dietary patterns translate into positive associations with clinical fertility endpoints such as assisted reproductive technology success rates or time-to-pregnancy among couples trying to conceive without medical assistance remains unclear. Male caffeine and alcohol intake, within low-to-moderate ranges of intake, do not appear to be detrimental to semen quality. Yet high-quality research on this topic, focused on clinical fertility endpoints, should continue given the conflicting evidence, particularly in populations undergoing infertility treatment with assisted reproductive technology. Recreational drug use, including marijuana, electronic cigarettes, and other illicit drugs, does not appear to be beneficial for male reproductive health and should be avoided or ceased. In conclusion, men should be encouraged to consume a healthy diet rich in fruits, vegetables, whole grains, nuts, low-fat dairy, and seafood, as well as lacking in red and processed meats, sweets, and sugar-sweetened beverages, and to avoid recreational drug use for improved male reproductive health.

How Food Choices Impact on Male Fertility

PURPOSE OF REVIEW

Increasing evidence on the significance of nutrition in reproduction is emerging from both animal and human studies, suggesting an association between nutrition and male fertility. Here, we have highlighted the impact of the various food groups on reproductive hormones and on spermatogenesis, and the effects of classical and latest dietary patterns such as Mediterranean diet, Western diet, intermittent fasting, ketogenic diet, and vegan/vegetarian diet on male fertility.

RECENT FINDINGS

Nutrients are the precursors of molecules involved in various body's reactions; therefore, their balance is essential to ensure the correct regulation of different systems including the endocrine system. Hormones are strongly influenced by the nutritional status of the individual, and their alteration can lead to dysfunctions or diseases like infertility. In addition, nutrients affect sperm production and spermatogenesis, controlling sexual development, and maintaining secondary sexual characteristics and behaviors. The consumption of fruit, vegetables, fish, processed meats, dairy products, sugars, alcohol, and caffeine importantly impact on male fertility. Among dietary patterns, the Mediterranean diet and the Western diet are most strongly associated with the quality of semen. Nutrients, dietary patterns, and hormonal levels have an impact on male infertility. Therefore, understanding how these factors interact with each other is important for strategies to improve male fertility.

Association of diet and lifestyle factors with semen quality in male partners of Chinese couples preparing for pregnancy

BACKGROUND

Semen quality significantly influences conception, and its preservation is crucial for couples seeking pregnancy. We investigated dietary and lifestyle risk factors impacting semen quality.

METHODS

A total of 466 males from the Guangzhou Women and Children's Medical Center's pre-pregnancy consultation clinic were recruited between January 2021 and March 2023 for inclusion. Semen analysis was performed, and diet and lifestyle data were gathered via questionnaire. Logistic regression was utilized to examine the link between diet, lifestyle variables, and semen quality.

RESULTS

Smoking worsened progressive sperm motility (38.0% vs. 36.0%, t = 2.262; P = 0.049). Alcohol consumption impaired progressive motility (40.5 ± 17.8% vs. 34.7 ± 16.1%, t = 3.396; P < 0.001) and total motility (56.0% vs. 64.0%; P = 0.001). Using plastic beverage bottles for oil or seasonings lowered sperm concentrations (40.4% vs. 59.0% vs. 65.5%; P = 0.032). A sweet diet correlated with higher total sperm motility (55.0% vs. 60.0%, 62.0% vs. 63.2%; P = 0.017). Higher milk product intake improved sperm concentration (41.6106 vs. 63.7106 vs. 66.1*106; P = 0.021) and motility (54.5% vs. 56.0% vs. 63.0%; P = 0.033). More frequent egg consumption increased semen volume (3.1 mL vs. 3.8 mL vs. 4.0 mL; P = 0.038). Roughage intake enhanced sperm concentration (160.8106 vs. 224.6106; P = 0.027), and adequate sleep improved progressive sperm motility rate (35.4% ± 18.2% vs. 40.2 ± 16.3%, F = 3.747; P = 0.024) and total motility (52.7% vs. 61.5%; P = 0.013). The regression model showed that using plastic containers for condiments was a protective factor for semen volume (OR: 0.12; CI 0.03-0.55; P = 0.006), sperm concentration (OR: 0.001, CI 0.00-0.30; P = 0.012), and count (OR: 0.12, CI 0.03-0.48; P = 0.003). Milk and egg consumption were also protective for semen volume (OR: 0.18, CI 0.06-0.51; P = 0.001 and OR: 0.11, CI 0.03-0.55; P = 0.006, respectively), while sufficient sleep benefitted total sperm motility (OR: 0.47, CI 0.24-0.95; P = 0.034).

CONCLUSIONS

Smoking and drinking, type of condiment container, diet preference, sleep duration, and milk, roughage, and egg consumption may reduce semen quality.

Deteriorating Semen Quality: The Role of the Environment

Since the end of the last century, several reports have suggested that semen quality is declining, especially in Western countries. Furthermore, cross-sectional studies using similar protocols have suggested regional differences in semen quality of young and fertile men. Reasons for these regional differences and local adverse trends in semen quality are unknown, but environmental factors are suspected to have a role. Besides adulthood environmental exposures, those occurring during testicular development may also affect semen quality. Longitudinal follow-up studies and mixture risk analyses are needed to study the effect of fetal, childhood, and adult life environment on semen quality.

Association of living environmental and occupational factors with semen quality in chinese men: a cross-sectional study

Sperm quality can be easily influenced by living environmental and occupational factors. This study aimed to discover potential semen quality related living environmental and occupational factors, expand knowledge of risk factors for semen quality, strengthen men's awareness of protecting their own fertility and assist the clinicians to judge the patient's fertility. 465 men without obese or underweight (18.5 < BMI < 28.5 kg/m2), long-term medical history and history of drug use, were recruited between June 2020 to July 2021, they are in reproductive age (25 < age < 45 years). We have collected their semen analysis results and clinical information. Logistic regression was applied to evaluate the association of semen quality with different factors. We found that living environment close to high voltage line (283.4 × 106/ml vs 219.8 × 106/ml, Cohen d = 0.116, P = 0.030) and substation (309.1 × 106/ml vs 222.4 × 106/ml, Cohen d = 0.085, P = 0.015) will influence sperm count. Experienced decoration in the past 6 months was a significant factor to sperm count (194.2 × 106/ml vs 261.0 × 106/ml, Cohen d = 0.120, P = 0.025). Living close to chemical plant will affect semen PH (7.5 vs 7.2, Cohen d = 0.181, P = 0.001). Domicile close to a power distribution room will affect progressive sperm motility (37.0% vs 34.0%, F = 4.773, Cohen d = 0.033, P = 0.030). Using computers will affect both progressive motility sperm (36.0% vs 28.1%, t = 2.762, Cohen d = 0.033, P = 0.006) and sperm total motility (57.0% vs 41.0%, Cohen d = 0.178, P = 0.009). After adjust for potential confounding factors (age and BMI), our regression model reveals that living close to high voltage line is a risk factor for sperm concentration (Adjusted OR 4.03, 95% CI 1.15-14.18, R2 = 0.048, P = 0.030), living close to Chemical plants is a protective factor for sperm concentration (Adjusted OR 0.15, 95% CI 0.05-0.46, R2 = 0.048, P = 0.001) and total sperm count (Adjusted OR 0.36, 95% CI 0.13-0.99, R2 = 0.026, P = 0.049). Time spends on computer will affect sperm total motility (Adjusted OR 2.29, 95% CI 1.11-4.73, R2 = 0.041, P = 0.025). Sum up, our results suggested that computer using, living and working surroundings (voltage line, substation and chemical plants, transformer room), and housing decoration may association with low semen quality. Suggesting that some easily ignored factors may affect male reproductive ability. Couples trying to become pregnant should try to avoid exposure to associated risk factors. The specific mechanism of risk factors affecting male reproductive ability remains to be elucidated.

The Association between Circulating Lipids and Female Infertility Risk: A Univariable and Multivariable Mendelian Randomization Analysis

BACKGROUND

Although observational studies have demonstrated that blood lipids are associated with female infertility, the causality of this association remains unclear. We performed a univariable and multivariable Mendelian randomization (MR) analysis to evaluate the causal relationship between blood lipids and female infertility.

METHODS

Single-nucleotide polymorphisms associated with lipid traits in univariate analysis were obtained from the Million Veteran Program (MVP) and Global Lipids Genetics Consortium (GLGC), involving up to 215,551 and 188,577 European individuals, respectively. Blood lipids in multivariate analysis were obtained from the latest genome-wide association study meta-analysis with lipid levels in 73 studies encompassing >300,000 participants. Data on female infertility were obtained from the FinnGen Consortium R6 release, which included 6481 samples and 75,450 controls. Subsequently, MR analysis was performed using inverse variance-weighted (IVW), weighted median, weighted-mode, simple-mode and MR-Egger regression to demonstrate the causal relationship between lipids and female infertility.

RESULTS

After controlling confounding factors including body mass index and age at menarche, two-sample MR demonstrated that genetically predicted LDL-C and TC were causally associated with the risk of female infertility (When the genetic instruments come from the MVP database, LDL-C and female infertility, IVW OR: 1.13, 95% CI: 1.001-1.269, p = 0.047; TC and female infertility, IVW OR: 1.16, 95% CI: 1.018-1.317, p = 0.025, and when the genetic instruments came from the GLGC database, LDL-C and female infertility, IVW OR: 1.10, 95% CI: 1.008-1.210, p = 0.033; TC and female infertility, IVW OR: 1.14, 95% CI: 1.024-1.258, p = 0.015). However, the IVW estimate showed that HDL-C was not significantly associated with the risk of female infertility (when the genetic instruments came from the MVP database, IVW OR: 1.00, 95% CI: 0.887-1.128, p = 0.999; when the genetic instruments came from the GLGC database, IVW OR: 1.00, 95% CI: 0.896-1.111, p = 0.968). The multivariable MR analysis also provided evidence that LDL-C (OR: 1.12, 95% CI: 1.006-1.243, p = 0.042) was significantly associated with the risk of female infertility after considering the correlation of all lipid-related traits.

CONCLUSION

These findings support a causal relationship between increased LDL-cholesterol and increased female infertility risk. Furthermore, the association between lipid-related traits and female infertility risk merits more studies.

Male Clinical Parameters (Age, Stature, Weight, Body Mass Index, Smoking History, Alcohol Consumption) Bear Minimal Relationship to the Level of Sperm DNA Fragmentation

This retrospective cohort study reports on 1291 males who were the partners of women presenting with infertility requiring assisted reproduction and who had sperm DNA fragmentation (SDF) levels measured by the Halosperm test. These men provided clinical and biometric details which included their age, stature, weight, and body mass index (BMI). Of these men, 562 (43.5%) provided detailed historical records of their smoking and alcohol histories. The aim of this study was to determine whether any clinical and biometric parameters, or main lifestyle factors, had any influence on SDF. We found that the only clinical parameter with a direct correlation was that of advancing age (r = 0.064, p = 0.02), but none of the biometric parameters of stature, weight, or BMI showed any significant correlation. In respect to lifestyle, there were significant correlations with smoking history, but not in the way we expected. Our data showed significantly elevated SDF levels among non-smokers (p = 0.03) compared with smokers. We also found that, among the non-smokers, ex-smokers had higher SDF levels (p = 0.03). With respect to alcohol, consumers did not show any significant differences in SDF levels. These lifestyle findings did not show any significant relevance with respect to an SDF level of <15% or ≥15%. Furthermore, logistic regression analysis excluded age as a confounder in these lifestyle findings. It is therefore concluded that, apart from age, both clinical and lifestyle aspects have minimal relevance to SDF.

Protective Effect of Commercial Grade Vitamin C against Alcohol-induced Testicular Damage in Male Wistar Rats

Background

Alcohol consumption has a negative effect on male fertility, but Vitamin C may be able to alleviate this effect.

Aims

In this study, the protective effect of Vitamin C against alcohol-induced testicular damage in adult male Wistar rats was evaluated.

Settings and Design

This study was conducted in a University setting. Following a 14-day acclimatisation period, forty adult male Wistar rats were randomly divided into eight groups of five rats. The control group received only food and water, test group B received alcohol only, test group C to E received different doses of Vitamin C, test group F to G received different doses of Vitamin C and alcohol.

Materials and Methods

After a 21-day treatment period, the testis were harvested and analysed for sperm parameters, antioxidant enzyme activity, level of lipid peroxidation and histopathological changes.

Statistical Analysis Used

All analyses was performed using SPSS (version 16) and Microsoft Excel (2019) using Student's t-test.

Results

The results showed that in groups administered with alcohol only, there was a decrease in sperm count. Sperm motility, morphology, viability and antioxidant enzyme activity, but increase in the level of lipid peroxidation. In groups treated with Vitamin C and alcohol, there was improvement in the sperm parameters, antioxidant enzymes activity and a decrease and decrease in lipid peroxidation. Furthermore, in the histology of the testis, regenerative changes were seen.

Conclusion

The chronic consumption of alcohol can have a deleterious effect on the testis, but commercial-grade Vitamin C can reverse these effects.

Epigenetics Role in Spermatozoa Function: Implications in Health and Evolution-An Overview

The unique properties of spermatozoa are established through the spermatogenesis and maturation processes concurrently with its epigenome. It is known that damage to epigenetic mechanisms can lead to reproductive problems. However, scientific reviews addressing the role of the spermatozoa epigenome during the reproductive process are scarce. Therefore, the aim of this review was to offer a detailed overview of current knowledge in the field of spermatozoa epigenetics and its consequent implications. A full search was performed through three databases by combining five keywords. Inclusion criteria were implemented to grant accessibility, relevance, and concretion. Besides, some articles were manually removed or added to obtain an adequate and complete collection of 485 scientific publications. This compilation was used to conduct the bibliometric analysis and the data review separately. Bibliometric results displayed that spermatozoa epigenetics is an active and growing research area. The bibliographic overview showed that sperm epigenome correlates with the development of its function, explaining the environmental influence on reproductive pathologies or abnormal inheritance. The main conclusions were that the normal performance of sperm is heavily reliant on its epigenetics and that this study area is burgeoning, with the potential ability to provide society with clinical innovations in a short-term period.

Alcohol, smoke, cannabis, new psychoactive substances, and non-prescribed drugs consumption among school student in an area of Nord-West of Italy

BACKGROUND

Alcohol and/or substance use disorders are known to be a significant phenomenon in the Western world. The aim of the present study was to evaluate the consumption of alcohol, cigarette smoking, cannabis, new psychoactive substances (NSP) / non prescribed drug (NPD) in a student population in the north-west of Italy (metropolitan area of Genoa).

METHODS

Fourteen comprehensive schools in the metropolitan area of Genoa (Italy) have requested to participate in the education for correct lifestyles meetings (from December 16, 2021, to May 30, 2022). Before each meeting, a meeting was held with the reference teachers: 3805 students aged 9 to 17 were involved. The group was divided by age group: 9-11, 12-13, 14-15 and 16-17 years. Before the lesson, the students were given a questionnaire relating to various topics related to lifestyle or resulting from an incorrect lifestyle (alcohol consumption, cigarette smoking, cannabis, NPS/NPD, psychological path). The questionnaire was anonymous and was approved by the teachers in the preparation phase of the meeting.

RESULTS

Logistic regression analysis found that cannabis use in the age of 14-15 increases the risk of consuming NPD/NPD by more than 26 times (odd ratio 26.3012; 95% CI 15.9656 to 43.3275; P<0.0001). In the age of 16-17, this risk increases approximately 14 times (odd ratio 14.0625; 95% CI 6.1729 to 32.0360; P<0.0001). In the age of 14-15 years, cannabis consumption, alcohol consumption >2 alcoholic units (AUs) on one occasion, NPD increases the probability of the need for a psychological path (cannabis: odds ratio 14.0254, 95% CI 10.9-17.9, P<0.0001; alcohol: odds ratio 3.68, 95% CI 3-4.4, P<0.0001; NPS/NPD: odds ratio 20.98, 16.4-38.4, P<0.0001). In the age of 14-15 and 16-17 years, respectively, 53% (95% CI 50-58%) and 68% (95% CI 66-71%) of students declared that they had neither the parents nor the psychologist of having used alcohol and/or substances.

CONCLUSIONS

These data should be useful to policy makers to implement prevention and health promotion policies through teaching (education for correct lifestyles) to be permanently included in school programs and to be recognized in the curricular path.

In Vitro Combination of Ascorbic and Ellagic Acids in Sperm Oxidative Damage Inhibition

It is known that an altered redox balance interferes with normal spermatic functions. Exposure to genotoxic substances capable of producing oxidative stress (OS) can cause infertility in humans. The use of antioxidants to reduce oxidative stress contributes to the improvement in reproductive function. This study focused on an antigenotoxic evaluation of ellagic acid (EA) and ascorbic acid (AA) in combination against benzene genotoxic action on human spermatozoa in vitro. In addition to the evaluation of sperm parameters, damage in sperm genetic material and intracellular ROS quantification were assessed after AA, EA and benzene co-exposure using the TUNEL technique and DCF assay. The results showed that the combination of the two antioxidants generates a greater time-dependent antigenotoxic action, reducing both the sperm DNA fragmentation index and the oxidative stress. The genoprotective effect of AA and EA association in sperm cells lays the foundations for a more in-depth clinical study on the use of antioxidants as a therapy for male infertility.

Lutein Can Alleviate Oxidative Stress, Inflammation, and Apoptosis Induced by Excessive Alcohol to Ameliorate Reproductive Damage in Male Rats

Chronic excessive alcohol intake may lead to male reproductive damage. Lutein is a carotenoid compound with antioxidant activity. The purpose of this study was to observe the effect of lutein supplementation on male reproductive damage caused by excessive alcohol intake. In this study, an animal model of excessive drinking (12 mL/(kg.bw.d)) for 12 weeks was established and supplemented with different doses of lutein (12, 24, 48 mg/(kg.bw.d)). The results showed that the body weight, sperm quality, sex hormones (FSH, testosterone), and antioxidant markers (GSH-Px) decreased significantly, while MDA and inflammatory factors (IL-6, TNF-α) increased significantly in the alcohol model group when compared to the normal control group. After 12 weeks of high-dose lutein supplementation with 48mg/(kg.bw.d), the spermatogenic ability, testosterone level, and the activity of marker enzymes reflecting testicular injury were improved. In addition, high-dose lutein supplementation downregulated the NF-κB and the pro-apoptosis biomarkers (Bax, Cytc and caspase-3), whereas it upregulated the expression of Nrf2/HO-1 and the anti-apoptotic molecule Bcl-2. These findings were fully supported by analyzing the testicular histopathology and by measuring germ cell apoptosis. In conclusion, lutein protects against reproductive injury induced by excessive alcohol through its antioxidant, anti-inflammatory, and anti-apoptotic properties.

Local and Systemic Oxidative Stress Biomarkers for Male Infertility: The ORION Study

Infertility problems occur in around 10% of all couples worldwide, with male-factor infertility as the sole contributor in 20–30% of these cases. Oxidative stress (OS) is suggested to be associated with the pathophysiology of male infertility. In spermatozoa, OS can lead to damage to the cell membrane, resulting in disruption of DNA integrity and a decrease in motility. Established biomarkers for OS include free thiols and malondialdehyde (MDA), both representing different components of the reactive species interactome (RSI). This exploratory study aimed to investigate seminal plasma-free thiol and MDA levels in relation to semen parameters as defined by the World Health Organization (WHO) to determine if these markers are adequate to define local OS status. Furthermore, this study investigated if there is a relation between systemic and local OS status by comparing seminal concentrations of free thiol (R-SH, sulfhydryl groups, representing the extracellular redox status) and MDA (lipid peroxidation product) levels to those measured in serum. Free thiol and MDA measurements in both serum and semen plasma were performed in 50 males (18–55 y) of couples seeking fertility treatment. A significant positive correlation was found between seminal plasma-free thiol levels and sperm concentration and progressive motility (r = 0.383, p = 0.008 and r = 0.333, p = 0.022, respectively). In addition, a significant positive correlation was found between MDA levels in seminal plasma and sperm concentration (r = 0.314, p = 0.031). This study supports that seminal plasma-free thiols may be promising as local OS biomarkers. No associations were observed between local and systemic OS biomarker concentrations.