Obesity related metabolic endotoxemia is associated with oxidative stress and impaired sperm DNA integrity

Impact of metabolic syndrome factors on sperm DNA fragmentation in males from infertile couples: A systematic review and meta-analysis

PURPOSE

To investigate the impact of metabolic syndrome factors on sperm DNA fragmentation (sDF) in males from infertile couples.

METHODS

A systematic literature search was performed across ten databases for literature published from January 1, 2013 until September 13, 2023. The protocol has been registered on PROSPERO (CRD42023458359), and the literature search strategy is adhered to the PRISMA framework. Studies that evaluated sDF, as indicated by DNA fragmentation index (%DFI), in males from infertile couples in relation to metabolic syndrome factors were included. Meta-analysis, using random effects model and Bayesian framework network, was performed, and data were presented as Standardized Mean Differences (SMD) with corresponding 95 % Confidence Interval (CI).

RESULTS

Of the 2579 citations identified, eleven studies were included in this meta-analysis. The findings revealed that the %DFI was not associated with overall metabolic syndrome factors (p-tot = 0.235; SMD = 0.57 [95 %CI: -0.37, 1.52]), metabolic syndrome status (p-tot = 0.337; SMD = 0.08 [95 %CI: -0.08, 0.24), increased body mass index (p-tot = 0.237; SMD = 0.71 [95 %CI: -0.47, 1.89]), or glycaemic profile (p-tot = 0.93; SMD = 0.13 [95 %CI: -2.72, 2.98]). High levels of heterogeneity were observed (p < 0.01) in all subgroups, except for metabolic syndrome status.

CONCLUSION

The association between metabolic syndrome factors and sDF is conflicting. However, interpreting the association requires caution, as confounding factors, indicated by high heterogeneity, may conceal the outcome. Metabolic syndrome may influence other factors contributing to male infertility, highlighting the importance of promoting a healthy lifestyle.

Gut microbiota is involved in male reproductive function: a review

Globally, ~8%-12% of couples confront infertility issues, male-related issues being accountable for 50%. This review focuses on the influence of gut microbiota and their metabolites on the male reproductive system from five perspectives: sperm quality, testicular structure, sex hormones, sexual behavior, and probiotic supplementation. To improve sperm quality, gut microbiota can secrete metabolites by themselves or regulate host metabolites. Endotoxemia is a key factor in testicular structure damage that causes orchitis and disrupts the blood-testis barrier (BTB). In addition, the gut microbiota can regulate sex hormone levels by participating in the synthesis of sex hormone-related enzymes directly and participating in the enterohepatic circulation of sex hormones, and affect the hypothalamic-pituitary-testis (HPT) axis. They can also activate areas of the brain that control sexual arousal and behavior through metabolites. Probiotic supplementation can improve male reproductive function. Therefore, the gut microbiota may affect male reproductive function and behavior; however, further research is needed to better understand the mechanisms underlying microbiota-mediated male infertility.

Germline cell de novo mutations and potential effects of inflammation on germline cell genome stability

Uncontrolled pathogenic genome mutations in germline cells might impair adult fertility, lead to birth defects or even affect the adaptability of a species. Understanding the sources of DNA damage, as well as the features of damage response in germline cells are the overarching tasks to reduce the mutations in germline cells. With the accumulation of human genome data and genetic reports, genome variants formed in germline cells are being extensively explored. However, the sources of DNA damage, the damage repair mechanisms, and the effects of DNA damage or mutations on the development of germline cells are still unclear. Besides exogenous triggers of DNA damage such as irradiation and genotoxic chemicals, endogenous exposure to inflammation may also contribute to the genome instability of germline cells. In this review, we summarized the features of de novo mutations and the specific DNA damage responses in germline cells and explored the possible roles of inflammation on the genome stability of germline cells.

The impact of obesity and metabolic health on male fertility: a systematic review

The impact of paternal obesity and metabolic disease on semen quality and fertility outcomes is not fully appreciated. With increasing obesity rates, researchers have studied the intricate relationship between paternal body mass index, metabolic health, and male fertility. This systematic review identified 112 articles in the MEDLINE database between 2013 and 2023 that investigated the effects of body mass index, diabetes, metabolic syndrome, exercise, weight loss medication, or bariatric surgery on semen parameters, sperm quality, or fertility outcomes. This review suggests that obesity, diabetes, and metabolic syndrome have a negative impact on various parameters of male fertility, from semen quality to sperm deoxyribonucleic acid integrity. There is also mounting evidence that male obesity is correlated negatively with live births via both natural conception and assisted reproductive technologies. Lifestyle interventions, such as physical exercise, generally appear to improve male fertility markers; however, the type and intensity of exercise may play a crucial role. Pharmacologic treatments for weight loss, such as metformin and glucagon-like peptide 1 agonists, present a more complex picture, with studies suggesting both beneficial and detrimental effects on male reproductive health. Similarly, surgical interventions, such as gastric bypass surgery, show promise in improving hormonal imbalances but have mixed effects on semen parameters. Future research is needed to clarify these associations and inform clinical guidelines. In the interim, health practitioners should incorporate these insights into clinical practices, encouraging proactive lifestyle changes and providing targeted treatments to improve male reproductive health.

Sperm DNA damage: The possible link between obesity and male infertility, an update of the current literature

Obesity prevalence worldwide is increasing significantly. Whilst maternal obesity has clear detrimental impacts on fertility, pregnancy and foetal outcomes, more recently there has been an increasing focus on the role of paternal obesity in human fertility. Recent meta-analyses have indicated that obesity in men negatively affects basic sperm parameters such as sperm count, concentration and motility, increases the incidence of infertility and reduces the chances of conception. Sperm DNA damage, typically characterised by DNA strand breaks and oxidation of DNA nucleotides, is a specialised marker of sperm quality that has been independently associated with recurrent miscarriage, reduced assisted reproduction success and increased mutational loads in subsequent offspring. Whilst, there are still conflicting data in humans as to the association of obesity in men with sperm DNA damage, evidence from rodent models is clear, indicating that male obesity increases sperm DNA damage. Human data are often conflicting because of the large heterogeneity amongst studies, the use of body mass index as the indicator of obesity and the methods used for detection of sperm DNA damage. Furthermore, comorbidities of obesity (i.e., heat stress, adipokines, insulin resistance, changes in lipids, hypogonadism and obstructive sleep apnoea) are also independently associated with increased sperm DNA damage that is not always modified in men with obesity, and as such may provide a causative link to the discrepancies amongst human studies. In this review, we provide an update on the literature regarding the associations between obesity in men and fertility, basic sperm parameters and sperm DNA damage. We further discuss potential reasons for the discrepancies in the literature and outline possible direct and indirect mechanisms of increased sperm DNA damage resulting from obesity. Finally, we summarise intergenerational obesity through the paternal linage and how sperm DNA damage may contribute to the transmission.

The Relationship between Body Mass Index, Metal Elements, and Antioxidant Capacity of Semen on The Human Sperm Chromatin

BACKGROUND

Sperm chromatin abnormalities are defects in nuclear maturation and DNA integrity. These defects originated from defective spermatogenesis due to a lack of DNA repair during chromatin remodeling. Changes in semen elements can cause damage to chromatin. There is little information about the relationship between changes in trace metal elements and total antioxidant capacity (TAC) with sperm chromatin damage. The present study was conducted to determine the relationship between Selenium (Se), Iron (Fe), Zinc (Zn), Copper (Cu) and the TAC of semen with the status of human sperm chromatin.

MATERIALS AND METHODS

In this experimental study, semen samples (n=30) were collected from healthy men referred to Kermanshah Motazadi Hospital and stored in liquid nitrogen; after thawing and centrifugation, sperm were separated. The atomic absorption method was used to measure the concentration of metal elements. The TAC was evaluated using the ferric-reducing antioxidant capacity of the plasma method. Furthermore, the integrity of sperm chromatin was measured using the sperm DNA fragmentation (SDF) method.

RESULTS

The status of sperm chromatin had a non-significant correlation with body mass index (BMI, P=0.25, r=0.21) and a non-significant negative correlation with sperm count (P=0.71, r=-0.71) and motility (P=0.75, r=0.61). In addition, there was no significant relationship between sperm chromatin and the TAC of semen (P=0.92, r=0.01). Additionally, there was no significant correlation between Se, Zn, or Cu concentration (P>0.05) and Fe concentration, which had a partially positive relationship with the chromatin state of sperm (P=0.24, r=0.20).

CONCLUSION

The trace metal elements in the seminal fluid did not play a significant role in the status of sperm chromatin.

Male obesity is associated with sperm telomere shortening and aberrant mRNA expression of autophagy-related genes

BACKGROUND

Obesity is regarded a global public health crisis. It has been implicated in a variety of health problems, but when it comes to male fertility, how and to what extent obesity affects it are poorly understood. Accordingly, semen samples from 32 individuals with obesity (body mass index (BMI) ≥ 30 kg/m²) and 32 individuals with normal weight (BMI: 18.5-25 kg/m²) were obtained. Here, for the first time, we examined the association between obesity, relative sperm telomere length (STL) and autophagy-related mRNA levels such as Beclin1, AMPKa1, ULK1, BAX, and BCL2. Each group was also evaluated for conventional semen parameters, sperm apoptotic changes, DNA fragmentation index (DFI), sperm chromatin maturation, and reactive oxygen species (ROS) levels.

RESULTS

Based on our findings, there was a marked reduction in relative STL in individuals with obesity as compared to the normal-weight group. We also found a significant negative correlation between relative STL and age, BMI, DFI, percentage of sperm with immature chromatin, and intracellular ROS levels in patients with obesity. In the normal-weight group, relative STL was only negatively correlated with DFI and intracellular ROS levels. Regarding mRNA expression, there was considerable upregulation of Beclin1, ULK1, and BCL2 in the group with obesity compared to the normal-weight group. Obesity was also found to be associated with a considerable decline in semen volume, total sperm count, progressive motility, and viability in comparison to normal-weight individuals. Furthermore, obesity was associated with considerably higher percentages of DFI, sperm with immature chromatin, late-stage apoptosis, and elevated ROS levels.

CONCLUSION

According to our findings, obesity is associated with sperm telomere shortening and aberrant autophagy-related mRNA expression. It should be emphasized that telomere shortening in sperm may be an indirect consequence of obesity due to the oxidative stress associated with the condition. Nevertheless, further investigation is required for a more comprehensive understanding.

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.

High-fat diet in mice led to increased severity of spermatogenesis impairment by lead exposure: perspective from gut microbiota and the efficacy of probiotics

BACKGROUND

The mechanism of multifactorial spermatogenesis impairment is unclear. This study aimed to investigate the reproductive toxicity of lead (Pb) in mice fed a high-fat diet (HFD) and to delineate the important role of gut microbiota.

RESULTS

Results showed that, compared with mice fed a normal diet (ND), Pb exposure caused more severe spermatogenesis impairment in HFD-fed mice, including decreased sperm count and motility, seminiferous tubule injury, serum and intratesticular testosterone decline, and downregulated expression level of spermatogenesis-related genes. Besides, 16S sequencing indicated that HFD-fed mice had increased severity of gut microbiota dysbiosis by Pb exposure compared to ND-fed mice. With fecal microbiota transplantation, the same trend of spermatogenesis impairment occurred in recipient mice, which confirmed the important role of gut microbiota. Moreover, probiotics supplementation restored the gut microbial ecosystem, and thus improved spermatogenic function.

CONCLUSION

Our work suggested that a population with HFD might face more reproductive health risks upon Pb exposure, and revealed an intimate linkage between microbiota dysbiosis and spermatogenesis impairment, accompanied by the potential usefulness of probiotics as prophylactic and therapeutic. © 2022 Society of Chemical Industry.

Obesity-induced oxidative stress and mitochondrial dysfunction negatively affect sperm quality

Obesity is a systemic metabolic disease that can induce male infertility or subfertility through oxidative stress. The aim of this study was to determine how obesity impairs sperm mitochondrial structural integrity and function, and reduces sperm quality in both overweight/obese men and mice on a high-fat diet (HFD). Mice fed the HFD demonstrated higher body weight and increased abdominal fat content than those fed the control diet. Such effects accompanied the decline in antioxidant enzymes, such as glutathione peroxidase (GPX) and catalase and superoxide dismutase (SOD) in testicular and epidydimal tissues. Moreover, malondialdehyde (MDA) content significantly increased in sera. Mature sperm in HFD mice demonstrated higher oxidative stress, including increased mitochondrial reactive oxygen species (ROS) levels and decreased protein expression of GPX1, which may impair mitochondrial structural integrity and reduce mitochondrial membrane potential (MMP) and ATP production. Moreover, cyclic AMPK phosphorylation status increased, whereas sperm motility declined in the HFD mice. Clinical studies demonstrated that being overweight/obese reduced SOD enzyme activity in the seminal plasma and increased ROS in sperm, accompanied by lower MMP and low-quality sperm. Furthermore, ATP content in the sperm was negatively correlated with increases in the BMI of all clinical subjects. In conclusion, our results suggest that excessive fat intake had similar disruptive effects on sperm mitochondrial structure and function, as well as oxidative stress levels in humans and mice, which in turn induced lower sperm motility. This agreement strengthens the notion that fat-induced increases in ROS and impaired mitochondrial function contribute to male subfertility.

Oxidative Stress in Men with Obesity, Metabolic Syndrome and Type 2 Diabetes Mellitus: Mechanisms and Management of Reproductive Dysfunction

Reactive oxygen species (ROS) are critical physiological mediators of cellular function, including male fertility. When ROS exceed antioxidant regulation, oxidative stress occurs which is detrimental to cellular function. Oxidative stress has been found to be a central mediator of obesity, metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM), as well as with male infertility. Human studies have correlated testicular oxidative stress in obese males, and animal studies have further provided insight into potential mechanisms of action. Management of oxidative stress is not well defined. Appropriate nutrition and exercise can be recommended for all diabetic patients, and weight loss for obese patients with MetS and T2DM. Consideration of dietary supplements including micronutrients, antioxidants or medicinal herbs are recommended. Metformin may also offer benefits on testicular oxidative stress and fertility parameters. Significantly more research on causation, mechanisms, clinical assessments and appropriate management of infertility on obesity, MetS and T2DM is still required.

Paternal obesity induces placental hypoxia and sex-specific impairments in placental vascularization and offspring metabolism

Paternal obesity predisposes offspring to metabolic dysfunction, but the underlying mechanisms remain unclear. We investigated whether this metabolic dysfunction is associated with changes in placental vascular development and is fueled by endoplasmic reticulum (ER) stress-mediated changes in fetal hepatic development. We also determined whether paternal obesity indirectly affects the in utero environment by disrupting maternal metabolic adaptations to pregnancy. Male mice fed a standard chow or high fat diet (60%kcal fat) for 8–10 weeks were time-mated with female mice to generate pregnancies and offspring. Glucose tolerance was evaluated in dams at mid-gestation (embryonic day (E) 14.5) and late gestation (E18.5). Hypoxia, angiogenesis, endocrine function, macronutrient transport, and ER stress markers were evaluated in E14.5 and E18.5 placentae and/or fetal livers. Maternal glucose tolerance was assessed at E14.5 and E18.5. Metabolic parameters were assessed in offspring at ~60 days of age. Paternal obesity did not alter maternal glucose tolerance but induced placental hypoxia and altered placental angiogenic markers, with the most pronounced effects in female placentae. Paternal obesity increased ER stress-related protein levels (ATF6 and PERK) in the fetal liver and altered hepatic expression of gluconeogenic factors at E18.5. Offspring of obese fathers were glucose intolerant and had impaired whole-body energy metabolism, with more pronounced effects in female offspring. Metabolic deficits in offspring due to paternal obesity may be mediated by sex-specific changes in placental vessel structure and integrity that contribute to placental hypoxia and may lead to poor fetal oxygenation and impairments in fetal metabolic signaling pathways in the liver.

Cordycepin alleviated metabolic inflammation in Western diet-fed mice by targeting intestinal barrier integrity and intestinal flora

Metabolic inflammation is a crucial factor in the pathogenesis of obesity and promotes related complications. Accumulating evidence has indicated that regulating intestinal integrity and the gut microbiota may be new treatment strategies for metabolic inflammation and obesity. Cordycepin has been reported to improve obesity, but the mechanism is not yet clear. Here, we showed that cordycepin considerably alleviated systemic inflammation while reducing body weight gain and metabolic disorders in Western diet (WD)-fed mice. Further investigations showed that cordycepin significantly ameliorated WD-induced damage to the intestinal barrier and decreased the leakage of lipopolysaccharide (LPS) into the blood in mice by suppressing intestinal inflammation, oxidative stress damage, and decreasing intestinal epithelial cell apoptosis and pyroptosis. In addition, by using metagenomic sequencing, we found that cordycepin can also regulate the homeostasis of intestinal flora, including selectively increasing the abundance of Akkermansia muciniphila and reducing the production of fecal LPS. Besides, we demonstrated that the intestinal flora partially mediated the beneficial effects of cordycepin on improving intestinal barrier function, and obesity-related symptoms in WD-fed mice by a fecal microbiota transplantation experiment. Hence, our findings provided new insights into the role of cordycepin in improving metabolic inflammation and obesity from the perspective of regulating the intestinal barrier function and intestinal flora, and further provided data support for the utility of cordycepin in the treatment of obesity and its complications.

Impact of metabolic syndrome on the viability of human spermatozoa: a cross-sectional descriptive study in men from infertile couples

Background

A direct association between metabolic syndrome (MetS) and sperm production/function has been proposed. In this cross-sectional study, we aimed to determine the impact of MetS on sperm survival. Men from infertile couples treated at Hue University Hospital, Vietnam, were enrolled in this study, which spanned the October 2018 to October 2020 period. The general characteristics of the patients, including body mass index (BMI), waist-to-hip ratio (WHR), the levels of different biochemicals, and semen parameters were determined, and sperm survival tests (SSTs) were performed. The modified National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III for the Asian population was used for MetS diagnosis.

Results

Men with an abnormal waist circumference (≥ 90 cm) showed a higher rate of abnormal SST results (30.1% vs. 16.7%, p = 0.012). The frequency of abnormal SST results in patients with MetS (72.3%) was significantly higher than that in individuals without MetS (53.4%) (p = 0.02). Furthermore, the percentage of abnormal SST results in patients with MetS and with BMI ≥ 23 was significantly higher than those in individuals without MetS (77.1% vs. 55.2%, p = 0.03). Weak negative correlations were also observed between the patients’ age and the SST results.

Conclusion

Sperm viability was lower in men with MetS. We also observed that age and BMI were independent factors associated with abnormal SST.

Bee bread mitigates downregulation of steroidogenic genes, decreased spermatogenesis, and epididymal oxidative stress in male rats fed with high-fat diet

The pituitary-gonadal axis plays an important role in steroidogenesis and spermatogenesis, and by extension, fertility. The aim of this study was to investigate the protective role of bee bread, a natural bee product, against obesity-induced decreases in steroidogenesis and spermatogenesis. Thirty-two adult male Sprague-Dawley rats weighing between 200 and 300 g were divided into four groups (n = 8/group), namely: normal control (NC), high-fat diet (HFD), HFD plus bee bread administered concurrently for 12 wk (HFD + B), HFD plus orlistat administered concurrently for 12 wk (HFD + O) groups. Bee bread (0.5 g/kg) or orlistat (10 mg/kg/day) was suspended in distilled water and given by oral gavage daily for 12 wk. Levels of follicle-stimulating hormone, luteinizing hormone, testosterone, and adiponectin, as well as sperm count, motility, viability, normal morphology, and epididymal antioxidants decreased, whereas levels of leptin, malondialdehyde, and sperm nDNA fragmentation increased significantly in the HFD group relative to the NC group. There were significant decreases in the testicular mRNA transcript levels of androgen receptor, luteinizing hormone receptor, steroidogenic acute regulatory protein, cytochrome P450 enzyme, 3β-hydroxysteroid dehydrogenase (HSD) and 17β-HSD in the testes of the HFD group. Furthermore, mount, intromission and ejaculatory latencies increased, and penile cGMP level decreased significantly in the HFD group. Supplementation with bee bread significantly reduced leptin level and increased adiponectin level, enhanced sperm parameters and reduced sperm nDNA fragmentation, upregulated the levels of steroidogenic genes and proteins in HFD-induced obese male rats. Bee bread improved steroidogenesis and spermatogenesis by upregulating steroidogenic genes. Therefore, bee bread may be considered as a potential supplementation to protect against infertility in overweight men or men with obesity.NEW & NOTEWORTHY The high-fat diet utilized in the present study induced obesity in the male rats. Bee bread supplementation mitigated impaired steroidogenesis, spermatogenesis, mating behavior, and fertility potential by counteracting the downregulation of steroidogenic genes, thus increasing testosterone levels and suppressing epididymal oxidative stress. These benefits may be due to the abundance of phenolic and flavonoid compounds in bee bread.

Should we be measuring DNA damage in human spermatozoa? New light on an old question

Assessments of sperm DNA damage are controversial because of perceived uncertainties over the relationship with pregnancy and the limited range of therapies available should positive results be returned. In this article, we highlight recent data supporting a chain of associations between oxidative stress in the male germ line, DNA damage in spermatozoa, defective DNA repair in the oocyte, the mutational load carried by the resulting embryo and the long-term health trajectory of the offspring. Any condition capable of generating oxidative damage in spermatozoa (age, obesity, smoking, prolonged abstinence, varicocele, chemical exposures, radiation etc.) is capable of influencing offspring health in this manner, creating a range of pathologies in the progeny including neuropsychiatric disorders and cancer. If sperm DNA damage is detected, there are several therapeutic interventions that can be introduced to improve DNA quality prior to the use of these cells in ART. We therefore argue that infertility specialists should be engaged in the diagnosis and remediation of sperm DNA damage as a matter of best practice, in order to minimize the risk of adverse health outcomes in children conceived using ART.

Lycopene is superior to moringa in improving fertility markers in diet-induced obesity male rats

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Obesity contributes to male infertility.

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Can lycopene or moringa improve male infertility?

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Tested in a rodent model of diet-induced obesity.

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Lycopene was superior to Moringa in improving male fertility parameters.

Obesity is a condition of chronic tissue inflammation and oxidative stress that poses as a risk factor for male infertility. Moringa oleifera oil extract is known to have cholesterol-lowering properties and a potential to treat obesity, while lycopene is a potent antioxidant. We hypothesize that Moringa or lycopene may improve male fertility markers in an animal model of diet-induced obesity. Male Albino rats (n = 60) were randomized to receive regular chow (RC) or high-fat diet (HFD) for 12 weeks (n = 30 each). Animals in each arm were further randomized to receive gavage treatment with corn oil (vehicle), lycopene (10 mg/kg), or Moringa (400 mg/kg) for four weeks starting on week 9 (n = 10 each). Animals were sacrificed at 12 weeks, and blood was collected to assess lipid profile, serum testosterone, and gonadotropin levels. The testes and epididymides were removed for sperm analysis, oxidative stress and inflammatory markers, and histopathological assessment. In comparison to their RC littermates, animals on HFD showed an increase in body weights, serum lipids, testosterone and gonadotrophin levels, testicular oxidative stress and inflammatory markers, as well as sperm abnormalities and disrupted testicular histology. Moringa or lycopene reduced body weight, improved oxidative stress, and male fertility markers in HFD-fed animals with lycopene exhibiting better anti-antioxidant and anti-lipidemic effects. Lycopene is superior to Moringa in improving male fertility parameters, possibly by attenuating oxidative stress.

Use of a male antioxidant nutraceutical is associated with superior live birth rates during IVF treatment

Oxidative stress is prevalent among infertile men and is a significant cause of sperm DNA damage. Since sperm DNA damage may reduce embryo quality and increase miscarriage rates, it is possible that untreated sperm oxidative stress may impair in vitro fertilization (IVF) live birth rates. Given that the antioxidant Menevit is reported to reduce sperm DNA damage, it was hypothesized that men's consumption of this supplement may alter IVF outcomes. Therefore, a retrospective cohort study was conducted analyzing outcomes for couples undergoing their first fresh embryo transfer. Men were classified as controls if they were taking no supplements, health conscious controls if taking “general health” supplements, or Menevit users. Men with karyotype abnormalities, or cycles using donated, frozen and surgically extracted sperm were excluded. Among the final study cohort of 657 men, live birth rates were significantly higher in Menevit users than controls (multivariate adjusted odds ratio [OR]: 1.57, 95% confidence interval [CI]: 1.01–2.45, P = 0.046), but not between controls taking no supplements and those using general health supplements, thereby suggesting that potential health conscious behavior in supplement users is unlikely responsible for the superior outcomes in Menevit users. Interestingly, in a post hoc sensitivity analysis, live birth rates among Menevit users were statistically superior to controls for lean men (OR: 2.73, 95% CI: 1.18–6.28; P = 0.019), not their overweight/obese counterparts (OR: 1.29, 95% CI: 0.75–2.22, P = 0.37). The results of this large cohort study therefore support a positive association between men's use of the Menevit antioxidant during IVF treatment and live birth rates, especially in lean individuals.

Sperm DNA Fragmentation: A New Guideline for Clinicians

Sperm DNA integrity is crucial for fertilization and development of healthy offspring. The spermatozoon undergoes extensive molecular remodeling of its nucleus during later phases of spermatogenesis, which imparts compaction and protects the genetic content. Testicular (defective maturation and abortive apoptosis) and post-testicular (oxidative stress) mechanisms are implicated in the etiology of sperm DNA fragmentation (SDF), which affects both natural and assisted reproduction. Several clinical and environmental factors are known to negatively impact sperm DNA integrity. An increasing number of reports emphasizes the direct relationship between sperm DNA damage and male infertility. Currently, several assays are available to assess sperm DNA damage, however, routine assessment of SDF in clinical practice is not recommended by professional organizations. This article provides an overview of SDF types, origin and comparative analysis of various SDF assays while primarily focusing on the clinical indications of SDF testing. Importantly, we report four clinical cases where SDF testing had played a significant role in improving fertility outcome. In light of these clinical case reports and recent scientific evidence, this review provides expert recommendations on SDF testing and examines the advantages and drawbacks of the clinical utility of SDF testing using Strength-Weaknesses-Opportunities-Threats (SWOT) analysis.

High or Low Body Fat Deposition in the Presence of a Normal Oral Sugar Test is Not Associated With Postthaw Semen Parameters in Stallions

This study compared the postthaw semen parameters of stallions with high and low body condition score (BCS) and evaluated associations between body morphometric parameters and postthaw semen parameters. Twenty stallions were split into Low BCS (BCS<7, n = 11) and High BCS (BCS ≥7, n = 9) groups, and underwent a complete morphometric analysis (e.g., neck scores and circumference, crest neck height, body weight, and height), and subcutaneous body fat thickness (SFT) at the tail head, withers, shoulders, and retroperitoneal space. A fasted oral sugar test (OST) was conducted on all stallions. One ejaculate from each stallion was frozen with a commercial egg yolk-based extender. Postthaw sperm motility parameters, plasma membrane integrity, mitochondrial membrane potential, hydrogen peroxide and intracellular superoxide production, and lipid peroxidation were analyzed for all stallions. The circumference at 25% and 50% of the neck's length were larger for High-BCS stallions (P < .05). There were no differences between groups for the neck crest height (P > .05). Stallions with High BCS had greater SFT at the tail head than stallions with Low BCS (P < .05); however, there were no differences between groups in the SFT at the shoulders and withers (P > .05). All stallions had resting blood glucose below the cutoff for equine metabolic syndrome. There were no differences between groups for resting glucose concentrations or for a peak at 30 or 60 minutes after initiation of the OST (P > .05). There were no differences in sperm parameters between groups (P > .05). Collectively, the findings of the present study suggest that High BCS or Low BCS in the presence of normal OST do not explain post-thaw semen parameters.

Impairment of spermatogenesis and sperm motility by the high-fat diet-induced dysbiosis of gut microbes

OBJECTIVE

High-fat diet (HFD)-induced metabolic disorders can lead to impaired sperm production. We aim to investigate if HFD-induced gut microbiota dysbiosis can functionally influence spermatogenesis and sperm motility.

DESIGN

Faecal microbes derived from the HFD-fed or normal diet (ND)-fed male mice were transplanted to the mice maintained on ND. The gut microbes, sperm count and motility were analysed. Human faecal/semen/blood samples were collected to assess microbiota, sperm quality and endotoxin.

RESULTS

Transplantation of the HFD gut microbes into the ND-maintained (HFD-FMT) mice resulted in a significant decrease in spermatogenesis and sperm motility, whereas similar transplantation with the microbes from the ND-fed mice failed to do so. Analysis of the microbiota showed a profound increase in genus Bacteroides and Prevotella, both of which likely contributed to the metabolic endotoxaemia in the HFD-FMT mice. Interestingly, the gut microbes from clinical subjects revealed a strong negative correlation between the abundance of Bacteroides-Prevotella and sperm motility, and a positive correlation between blood endotoxin and Bacteroides abundance. Transplantation with HFD microbes also led to intestinal infiltration of T cells and macrophages as well as a significant increase of pro-inflammatory cytokines in the epididymis, suggesting that epididymal inflammation have likely contributed to the impairment of sperm motility. RNA-sequencing revealed significant reduction in the expression of those genes involved in gamete meiosis and testicular mitochondrial functions in the HFD-FMT mice.

CONCLUSION

We revealed an intimate linkage between HFD-induced microbiota dysbiosis and defect in spermatogenesis with elevated endotoxin, dysregulation of testicular gene expression and localised epididymal inflammation as the potential causes.

TRIAL REGISTRATION NUMBER

NCT03634644.

Impact of body mass index and metabolic syndrome on sperm DNA fragmentation in males from infertile couples: A cross-sectional study from Vietnam

Objectives

This study investigated the relationship between body mass index (BMI) and metabolic syndrome on sperm DNA fragmentation (SDF) in males from infertile couples.

Methods

This cross-sectional study was performed from September 2018 to September 2019 at the Hue Center for Reproductive Endocrinology and Infertility (HUECREI), Vietnam. The study included men from couples with at least one year of infertility, who were subjected to semen analysis and SDF assay (Halosperm). We also performed a 2-h oral glucose tolerance test and measured lipidemia. Metabolic syndrome (MetS) was defined based on the NHLBI/AHA-ATP III guidelines.

Results

The mean age of the patients was 35.26 ± 5.87 years and 53.8% of them had a BMI ≥23.0 kg/m². The DNA fragmentation index was significantly associated with overweight (p = 0.024). Men without MetS had a higher rate of big halos and a lower rate of small halos, no halos, and degraded semen compared to that in men with MetS, but the differences were not significant (p > 0.05). By performing multivariable analysis, we found that the SDF value was significantly different among the two groups with either overweight or normal weight.

Conclusion

In males from infertile couples with a relatively young mean age, BMI can be an independent indicator for SDF. MetS thus has a significant role in the development of sperm DNA fragmentation, at least in overweight individuals; it should thus be assessed under the scope of BMI, for better/earlier detection of increased SDF.

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Sperm DNA fragmentation recently appears to be a good marker for male reproductive potential.

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BMI can be an independent indicator for increasing SDF.

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MetS has a significant role in the development of SDF, at least in overweight individuals.

Early Life Oxidative Stress and Long-Lasting Cardiovascular Effects on Offspring Conceived by Assisted Reproductive Technologies: A Review

Assisted reproductive technology (ART) has rapidly developed and is now widely practised worldwide. Both the characteristics of ART (handling gametes/embryos in vitro) and the infertility backgrounds of ART parents (such as infertility diseases and unfavourable lifestyles or diets) could cause increased oxidative stress (OS) that may exert adverse influences on gametogenesis, fertilisation, and foetation, even causing a long-lasting influence on the offspring. For these reasons, the safety of ART needs to be closely examined. In this review, from an ART safety standpoint, the origins of OS are reviewed, and the long-lasting cardiovascular effects and potential mechanisms of OS on the offspring are discussed.

Protective effect of vitamin E on sperm parameters in rats infected with Candida albicans

Candida albicans is one of the most frequent pathogens present in the reproductive system. The negative in vitro effects of C. albicans on sperm functions have previously been studied. The current study was undertaken to investigate the effects of C. albicans infection in vivo on sperm quality and to evaluate the efficacy of vitamin E administration in rats infected with C. albicans. In this study, 5 days after infection induction, animals were treated with vitamin E for 5 weeks. Thereafter, sperm parameters, lipid peroxidation (LPO), total antioxidant capacity (TAC), hormonal analysis and testis histology were evaluated. Based on the results, sperm parameters and TAC significantly reduced, while LPO and tissue damage increased (p ≤ .05) following the infection. Hormone analysis showed low LH and testosterone levels in serum of the infected rats. Treatment with vitamin E significantly (p ≤ .05) improved sperm quality and testis histology, increased TAC and reduced LPO. In addition, vitamin E administration significantly increased (p ≤ .05) serum LH and testosterone levels. These results clearly indicate that vitamin E is effective in attenuating the adverse effects of C. albicans infection on male fertility and could be used as a complementary treatment for patients who suffer from fertility disorders following C. albicans infection.

Reasons for worldwide decline in male fertility

PURPOSE OF REVIEW

To review the evidence regarding a decrease in worldwide sperm parameters and discuss potential causative factors.

RECENT FINDINGS

The topic of worldwide decline in sperm parameters is contentious; however, recent high-quality studies have demonstrated that there is indeed a decline in sperm parameters. Several retrospective and basic science studies have shown possible links for this decline in sperm parameters such as obesity, diet, and environmental toxins.

SUMMARY

There exist substantial data to suggest a decline in sperm counts over time. Although causative factors have yet to be fully elucidated, potential causes include, increased rates of obesity, poor diet, and exposure to environmental toxins. How this decline in sperm counts reflects fertility has yet to be determined. As such, further studies are necessary to evaluate whether this decline in sperm count correlates with decreased fecundity and how to identify and mitigate potential causative factors.

Increased BMI 'alone' does not negatively influence sperm function - a retrospective analysis of men attending fertility treatment with corresponding liver function results

Does increased body mass index (BMI) without an underlying metabolic issue negatively influence semen quality? Proof of concept we conducted retrospective data analysis of men (N = 84) undergoing assisted reproductive technology, who had liver function testing with fasted glucose concentrations and corresponding hormone profile (testosterone, LH, FSH and prolactin) and semen analysis. Sperm count and total concentration were only reduced in metabolically unhealthy overweight/obese men. Serum GTT was the biggest predictor of Normozoospermia and Oligospermia, with BMI having no effect. Increased BMI without an underlying metabolic condition (in particular signs of NAFLD) has no influence on semen quality.

Adenosine accumulation causes metabolic disorders in testes and associates with lower testosterone level in obese mice

Overweight and obese men face numerous health problems, including type 2 diabetes, subfertility, and even infertility. However, few studies have focused on the effects of nutritional status and obesity-related regulatory signals on fertility deficiency. Our previous observations have shown that the elevation of plasma 5'-adenosine monophosphate (5'-AMP) and the accumulation of adenosine in liver and muscle of obese diabetic db/db mice are related to insulin resistance. Here, we found that adenosine accumulation in testis is a common marker of both genetic obesity and high-fat-diet induced obese mice. An messenger RNA sequencing analysis indicated that 78 upregulated genes and 155 downregulated genes in the testis of 5'-AMP-treated mice overlapped with the same genes in the testis of ob/ob mice, and these genes belonged to the clusters of steroid metabolic process and regulation of hormone levels, respectively. Serum testosterone was reduced in ob/ob and 5'-AMP-treated mice. Metabolomic analysis based on ¹ H nuclear magnetic resonance showed that the testicular metabolic profiles of ob/ob mice were similar to those of 5'-AMP treated mice. Exogenous 5'-AMP inhibited the phosphorylation of AKT and mammalian target of rapamycin signal transduction and reduced the proliferating cell nuclear antigen expressions in testes. Our results suggest that the accumulation of adenosine causes metabolic disorders in testes and associates lower testosterone level in obese mice.

The Importance of Oxidative Stress in Determining the Functionality of Mammalian Spermatozoa: A Two-Edged Sword

This article addresses the importance of oxidative processes in both the generation of functional gametes and the aetiology of defective sperm function. Functionally, sperm capacitation is recognized as a redox-regulated process, wherein a low level of reactive oxygen species (ROS) generation is intimately involved in driving such events as the stimulation of tyrosine phosphorylation, the facilitation of cholesterol efflux and the promotion of cAMP generation. However, the continuous generation of ROS ultimately creates problems for spermatozoa because their unique physical architecture and unusual biochemical composition means that they are vulnerable to oxidative stress. As a consequence, they are heavily dependent on the antioxidant protection afforded by the fluids in the male and female reproductive tracts and, during the precarious process of insemination, seminal plasma. If this antioxidant protection should be compromised for any reason, then the spermatozoa experience pathological oxidative damage. In addition, situations may prevail that cause the spermatozoa to become exposed to high levels of ROS emanating either from other cells in the immediate vicinity (particularly neutrophils) or from the spermatozoa themselves. The environmental and lifestyle factors that promote ROS generation by the spermatozoa are reviewed in this article, as are the techniques that might be used in a diagnostic context to identify patients whose reproductive capacity is under oxidative threat. Understanding the strengths and weaknesses of ROS-monitoring methodologies is critical if we are to effectively identify those patients for whom treatment with antioxidants might be considered a rational management strategy.