Impact of Varicocele on Testicular Oxidative Stress and Sperm Parameters in Experimental Animals: A Systematic Review and Meta-Analysis.

PURPOSE: Varicocele has been associated with high seminal oxidative stress (OS), impaired semen quality, and reduced male fertility potential. However, the exact mechanism(s) underlying the development of varicocele-mediated infertility and the cause-effect relationship between varicocele and testicular dysfunction are not fully understood. The aim of this systematic review and meta-analysis (SRMA) is to investigate the impact of varicocele on testicular OS markers and sperm parameters in experimental animals with varicocele as compared to animals without varicocele. MATERIALS AND METHODS: A literature search was performed using the Scopus and PubMed databases on studies that investigated testicular OS markers and sperm parameters in animals with varicocele. The primary outcomes included malondialdehyde (MDA) (nmol/mg) levels whereas the secondary outcomes included total sperm count (×106), sperm vitality (%), total sperm motility (%), and sperm DNA fragmentation (SDF) (%). Standardized mean difference (SMD) (95% confidence interval [CI]) was chosen to express the effect size. The quality of the included studies was evaluated using the Cambridge Quality Checklist. RESULTS: Out of 76 identified articles, 6 studies on rats were included in the meta-analysis. The analysis showed a significant increase of MDA (SMD: 15.61 [1.93, 29.29]; p=0.03) in rats with varicocele vs. controls. We also observed a significant decrease in total sperm count (SMD: -17.45 [-28.97, -5.93]; p<0.01), sperm vitality (SMD: -16.41 [-26.30, -6.52]; p<0.01), total sperm motility (SMD: -17.67 [-24.90, -10.44]; p<0.01), and a significant increase of SDF (SMD: 7.41 [1.23, 13.59]; p=0.02), in rats with varicocele vs. controls. The quality of the included studies was ranked as high. CONCLUSIONS: This SRMA indicates a significant increase in levels of testicular MDA and SDF and a reduction of sperm quality in experimental animals with varicocele. These findings support the potential role of testicular OS in the development of varicocele-induced testicular damage.

Membrane Cholesterol Inhibits Progesterone-Mediated Sperm Function through the Possible Involvement of ABHD2.

Abhydrolase domain containing 2-acylglycerol lipase (ABHD2) was recently claimed as the membrane receptor of progesterone (P4) in sperm cells, mediating cell processes such as sperm chemotaxis and acrosome reaction. Here, we investigated the role of membrane cholesterol (Chol) on ABHD2-mediated human sperm chemotaxis. Human sperm cells were obtained from twelve normozoospemic healthy donors. ABHD2-Chol interaction was modelled by computational molecular-modelling (MM). Sperm membrane Chol content was depleted by incubating cells with cyclodextrin (CD) or augmented by the incubation with the complex between CD and Chol (CD:Chol). Cell Chol levels were quantified by liquid chromatography-mass spectrometry. Sperm migration upon P4 gradient was evaluated through the accumulation assay in a specific migration device. Motility parameters were evaluated by sperm class analyzer, whilst intracellular calcium concentration, acrosome reaction and mitochondrial membrane potential were evaluated with calcium orange, FITC-conjugated anti-CD46 antibody and JC-1 fluorescent probes, respectively. MM analysis showed the possible stable binding Chol to ABHD2, resulting in to major impact on the protein backbone flexibility. The treatment with CD was associated with a dose-dependent increase in sperm migration in a 160 nM P4 gradient, together with increase in sperm motility parameters and levels of acrosome reaction. The treatment with CD:Chol was associated with essentially opposite effects. Chol was, thus, suggested to inhibit P4-mediated sperm function through the possible inhibition of ABHD2.

Ketone Body ß-Hydroxy-Butyrate Sustains Progressive Motility in Capacitated Human Spermatozoa: A Possible Role in Natural Fertility.

Background Calorie restriction is recognized as a useful nutritional approach to improve the endocrine derangements and low fertility profile associated with increased body weight. This is particularly the case for dietary regimens involving ketosis, resulting in increased serum levels of ketone bodies such as ß-hydroxy-butyrate (ß-HB). In addition to serum, ß-HB is detected in several biofluids and ß-HB levels in the follicular fluid are strictly correlated with the reproductive outcome in infertile females. However, a possible direct role of ketone bodies on sperm function has not been addressed so far. Methods Semen samples were obtained from 10 normozoospermic healthy donors attending the University Andrology Unit as participants in an infertility survey programme. The effect of ß-HB on cell motility in vitro was evaluated on isolated spermatozoa according to their migratory activity in a swim-up selection procedure. The effect of ß-HB on spermatozoa undergone to capacitation was also assessed. Results Two hours of exposure to ß-HB, 1 mM or 4 mM, proved to be ineffective in modifying the motility of freshly ejaculated spermatozoa isolated according to the migratory activity in a swim-up procedure (all p values > 0.05). Differently, sperm maintenance in 4 mM ß-HB after capacitation was associated with a significantly higher percentage of sperm cells with progressive motility compared to ß-HB-lacking control (respectively, 67.6 ± 3.5% vs. 55.3 ± 6.5%, p = 0.0158). Succinyl-CoA transferase inhibitor abolished the effect on motility exerted by ß-HB, underpinning a major role for this enzyme. Conclusion Our results suggest a possible physiological role for ß-HB that could represent an energy metabolite in support of cell motility on capacitated spermatozoa right before encountering the oocyte.

Impact of Varicocele Repair on Semen Parameters in Infertile Men: A Systematic Review and Meta-Analysis.

PURPOSE: Despite the significant role of varicocele in the pathogenesis of male infertility, the impact of varicocele repair (VR) on conventional semen parameters remains controversial. Only a few systematic reviews and meta-analyses (SRMAs) have evaluated the impact of VR on sperm concentration, total motility, and progressive motility, mostly using a before-after analytic approach. No SRMA to date has evaluated the change in conventional semen parameters after VR compared to untreated controls. This study aimed to evaluate the effect of VR on conventional semen parameters in infertile patients with clinical varicocele compared to untreated controls. MATERIALS AND METHODS: A literature search was performed using Scopus, PubMed, Embase, and Cochrane databases following the Population Intervention Comparison Outcome (PICOS) model (Population: infertile patients with clinical varicocele; Intervention: VR [any technique]; Comparison: infertile patients with clinical varicocele that were untreated; Outcome: sperm concentration, sperm total count, progressive sperm motility, total sperm motility, sperm morphology, and semen volume; Study type: randomized controlled trials and observational studies). RESULTS: A total of 1,632 abstracts were initially assessed for eligibility. Sixteen studies were finally included with a total of 2,420 infertile men with clinical varicocele (1,424 patients treated with VR vs. 996 untreated controls). The analysis showed significantly improved post-operative semen parameters in patients compared to controls with regards to sperm concentration (standardized mean difference [SMD] 1.739; 95% CI 1.129 to 2.349; p<0.001; I²=97.6%), total sperm count (SMD 1.894; 95% CI 0.566 to 3.222; p<0.05; I²=97.8%), progressive sperm motility (SMD 3.301; 95% CI 2.164 to 4.437; p<0.01; I²=98.5%), total sperm motility (SMD 0.887; 95% CI 0.036 to 1.738; p=0.04; I²=97.3%) and normal sperm morphology (SMD 1.673; 95% CI 0.876 to 2.470; p<0.05; I²=98.5%). All the outcomes showed a high inter-study heterogeneity, but the sensitivity analysis showed that no study was sensitive enough to change these results. Publication bias was present only in the analysis of the sperm concentration and progressive motility. No significant difference was found for the semen volume (SMD 0.313; 95% CI -0.242 to 0.868; I²=89.7%). CONCLUSIONS: This study provides a high level of evidence in favor of a positive effect of VR to improve conventional semen parameters in infertile men with clinical varicocele. To the best of our knowledge, this is the first SRMA to compare changes in conventional semen parameters after VR with changes in parameters of a control group over the same period. This is in contrast to other SRMAs which have compared semen parameters before and after VR, without reference to a control group. Our findings strengthen the available evidence and have a potential to upgrade professional societies' practice recommendations favoring VR to improve conventional semen parameters in infertile men.

Metabolic Syndrome and Male Fertility: Beyond Heart Consequences of a Complex Cardiometabolic Endocrinopathy.

Metabolic syndrome (MetS) is a highly prevalent condition among adult males, affecting up to 41% of men in Europe. It is characterized by the association of obesity, hypertension, and atherogenic dyslipidemia, which lead to premature morbidity and mortality due to cardiovascular disease (CVD). Male infertility is another common condition which accounts for about 50% of cases of couple infertility worldwide. Interestingly, male infertility and MetS shares several risk factors (e.g., smoking, ageing, physical inactivity, and excessive alcohol consumption), leading to reactive oxygen species (ROS) production and increased oxidative stress (OS), and resulting in endothelial dysfunction and altered semen quality. Thus, the present narrative review aims to discuss the pathophysiological mechanisms which link male infertility and MetS and to investigate the latest available evidence on the reproductive consequences of MetS.

Comprehensive Analysis of Global Research on Human Varicocele: A Scientometric Approach.

PURPOSE: This study provides a comprehensive analysis of research trends on the etiology, mechanisms, potential risk factors, diagnosis, prognosis, surgical and non-surgical treatment of varicocele, and clinical outcomes before and after varicocele repair. MATERIALS AND METHODS: Varicocele studies published between 1988 and 2020 were retrieved from the Scopus database on April 5, 2021. Original studies on human varicocele were included, irrespective of language. Retrieved articles were manually screened for inclusion in various sub-categories. Bibliometric data was subjected to scientometric analysis using descriptive statistics. Network, heat and geographic mapping were generated using relevant software. RESULTS: In total, 1,943 original human studies on varicocele were published. These were predominantly from the northern hemisphere and developed countries, and published in journals from the United States and Germany. Network map analysis for countries showed several interconnected nodal points, with the USA being the largest, and Agarwal A. from Cleveland Clinic, USA, being a center point of worldwide varicocele research collaborations. Studies of adolescents were underrepresented compared with studies of adults. Studies on diagnostic and prognostic aspects of varicocele were more numerous than studies on varicocele prevalence, mechanistic studies and studies focusing on etiological and risk factors. Varicocele surgery was more investigated than non-surgical approaches. To evaluate the impact of varicocele and its treatment, researchers mainly analyzed basic semen parameters, although markers of seminal oxidative stress are being increasingly investigated in the last decade, while reproductive outcomes such as live birth rate were under-reported in the literature. CONCLUSIONS: This study analyzes the publication trends in original research on human varicocele spanning over the last three decades. Our analysis emphasizes areas for further exploration to better understand varicocele's impact on men's health and male fertility.

Could SARS-CoV-2 infection affect male fertility and sexuality?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of coronavirus infectious disease (COVID-19) and has rapidly spread worldwide, causing serious problems to the healthcare systems of many countries and hundreds of thousand deaths. In this review we discuss data from the literature to understand whether the various districts of the male reproductive system may represent another vulnerable target for SARS-CoV-2. Studies were searched from electronic databases such as Google Scholar, PubMed, Scopus, and COVID-19 specific databases such as LitCovid, until July 31, 2021. It appears that SARS-CoV-2 virus infection not only causes damage to the respiratory system, but could have a serious impact on the reproductive system of male patients modulating many physiological processes. Like some other infections, SARS-CoV-2 also leads to a worsening of semen quality and an increase in oxidative stress (OS) levels. However, due to the limited number of studies, it is unclear whether this deterioration in semen parameters is temporary or lasts over time. It is certainly important that patients' reproductive function is monitored after coronavirus infection to avoid problems in reproductive health in the future.

Homocysteine levels correlate with velocimetric parameters in patients with erectile dysfunction undergoing penile duplex ultrasound.

INTRODUCTION: Hyperhomocysteinemia may contribute to the development of endothelial dysfunction and, consequently, atherosclerosis, a systemic disease involving the vessels that may affect the cavernous arteries leading to vasculogenic erectile dysfunction. Our study aims therefore to explore the relationship between homocysteine levels and velocimetric parameters detected by basal penile duplex ultrasound such as peak systolic velocity and flaccid penile acceleration in patients with erectile dysfunction. METHODS: A cross-sectional study was conducted collecting clinical, metabolic, hormonal, and instrumental (basal penile duplex ultrasound) data in patients affected by vasculogenic erectile dysfunction. RESULTS: Data of 126 subjects affected by erectile dysfunction were collected. Mean age was 52.1 ± 12.6 years, whereas mean body mass index was 25.6 ± 4.0 kg/m2 . Basal penile duplex ultrasound showed peak systolic velocity values of 13.1 ± 2.9 cm/s and mean flaccid penile acceleration of 2.28 ± 0.70 m/s2 , with a strong correlation among these two parameters (r = 0.690; p < 0.001). Frankly pathological values of peak systolic velocity and flaccid penile acceleration were detected in 39.7% and 4.8% of the subjects examined, respectively. Mean homocysteine levels were 14.9 ± 9.5 µmol/l. Homocysteine values >15 µmol/l were found in 26% of the subjects with erectile dysfunction. Peak systolic velocity values and homocysteine levels showed an inverse correlation (r = -0.213; p = 0.03). Similarly, flaccid penile acceleration values were inversely correlated to homocysteine levels (r = -0.199; p = 0.05). In addition, an inverse correlation was found between both peak systolic velocity and flaccid penile acceleration and body mass index, atherogenic lipid pattern, and age. Homocysteine and metabolic parameters showed no significant correlations. CONCLUSION: Hyperhomocysteinemia is highly prevalent in erectile dysfunction patients. The results of our study show that homocysteine levels correlate with velocimetric parameters assessed by basal penile duplex ultrasound, confirming the role of hyperhomocysteinemia in the genesis of erectile dysfunction of arterial origin.

Global warming and testis function: A challenging crosstalk in an equally challenging environmental scenario.

Environmental pollution, accounting for both chemical and physical factors, is a major matter of concern due to its health consequences in both humans and animals. The release of greenhouse gases with the consequent increase in environmental temperature is acknowledged to have a major impact on the health of both animals and humans, in current and future generations. A large amount of evidence reports detrimental effects of acute heat stress on testis function, particularly on the spermatogenetic and steroidogenetic process, in both animal and human models, wich is largely related to the testis placement within the scrotal sac and outside the abdomen, warranting an overall scrotal temperature of 2°C-4°C lower than the core body temperature. This review will provide a thorough evaluation of environmental temperature's effect on testicular function. In particular, basic concepts of body thermoregulation will be discussed together with available data about the association between testis damage and heat stress exposure. In addition, the possible association between global warming and the secular decline of testis function will be critically evaluated in light of the available epidemiological studies.

Pro-inflammatory cytokines and microRNAs in male infertility.

BACKGROUND: Male infertility is a problem that affects 10-15% of men of reproductive age. In particular, gametogenesis is a complex process in which inflammation may play a central role through the secretion of cytokines and the expression of microRNAs. We assessed the potential role of proinflammatory cytokines (TNF-α, IL-6 and IL-1α) and microRNAs (miR-146a-5p, miR-34a-5p and miR-23a-3p) in the seminal plasma of infertile men compared to controls, evaluating their correlation with seminal and biochemical parameters. METHODS AND RESULTS: Expression of cytokines and microRNAs was analyzed by ELISA and q-PCR. Our data shows that IL-1α was significantly increased in the azoospermic group compared to controls, TNF-α mRNA was more expressed in the oligozoospermic group than controls. There were no significant differences in miRNAs expression among the three groups. The correlations between sperm parameters and inflammatory markers were evaluated, however no significance was highlighted. CONCLUSIONS: The determination of each inflammatory marker separately in the seminal plasma of subfertile men, despite some significant differences, does not have a diagnostic value in male infertility even if an assay of selective pro-inflammatory cytokines and microRNAs in the semen may improve the diagnosis of male infertility.

The impact of autoimmune systemic inflammation and associated medications on male reproductive health in patients with chronic rheumatological, dermatological, and gastroenterological diseases: A systematic review.

Autoimmune disorders currently affect 5%-8% of the global population, characterized by an aberrant chronic inflammatory response to self-antigens. The aim of this study was to systematically review the current available evidence investigating the impact of systemic autoimmune diseases and associated immunosuppressive treatment on fertility parameters of adult men. Clinical trials, observational studies, and case reports written in English and reporting semen analysis, evaluation of seminal oxidative stress, and/or sperm DNA fragmentation in patients affected by psoriasis and psoriatic arthritis, celiac disease, inflammatory bowel diseases, systemic lupus erythematosus, ankylosing spondylitis, hidradenitis suppurativa, uveitis, dermatomyositis, and rheumatoid arthritis were collected by searching on PubMed, EMBASE, OVID, Scopus, and Cochrane Library databases, with no limit of time. The study quality and the extent of bias in design, methods, and outcome assessment were evaluated by applying the Joanna Briggs Institute Critical Appraisal tools. Evidence suggested that various autoimmune diseases or relevant medications can adversely affect male fertility parameters and that patients may benefit of counseling and sperm cryopreservation. Clinical trials further investigating any adverse effect of autoimmunity and related thereby on male infertility are warranted, to develop appropriate guidelines for males diagnosed and treated for autoimmune disorders.

Seminal plasma miRNAs in Klinefelter syndrome and in obstructive and non-obstructive azoospermia.

MicroRNAs are small, non-coding, single-strand oligonucleotides which regulate gene expression. There is little evidence in the literature about their role in azoospermia and no studies have investigated their presence in the seminal plasma of men with Klinefelter syndrome. This retrospective study investigated if there were any differences in microRNA expression (miR-509-5p, miR-122-5p, miR-34b-3p, miR-34c-5p) in the seminal plasma of patients with obstructive azoospermia, non-obstructive azoospermia and Klinefelter syndrome. Hormone levels were also investigated to identify any correlations with microRNA expression. We analysed 200 subjects (40 Klinefelter syndrome, 60 non-obstructive azoospermia with a normal karyotype, 60 obstructive azoospermia and 40 who were normozoospermic). All subjects underwent semen examination. Total RNA was obtained from seminal plasma and microRNA expression was analysed by RT-qPCR. There was a significant reduction in the expression of all investigated miRNAs in the seminal plasma of all patient categories in comparison with controls. There was a weak negative correlation between FSH values and miR-509-5p expression in non-obstructive azoospermic patients (r = - 0.391; p = 0.014). We hypothesize that in non-obstructive azoospermia and Klinefelter syndrome patients, the downregulation of microRNAs may be caused by damage to the germ cells and aberrant spermatogenesis. In our opinion the identification of seminal plasma microRNAs deriving almost exclusively from the testes could be essential for the development of specific biomarkers for male infertility. The expression of such microRNAs, in combination with hormone values, could comprise testicular markers of abnormal spermatogenesis and failed mature sperm production.

Human sperm motility: a molecular study of mitochondrial DNA, mitochondrial transcription factor A gene and DNA fragmentation.

Alterations affecting the mitochondrial genome and chromatin integrity of spermatozoa impair male reproductive potential. This study aimed to evaluate the impact of mitochondrial DNA (mtDNA) copy number alterations on sperm motility and on the molecular mechanism regulating the number of mtDNA copies, through analysis of mitochondrial transcription factor A (TFAM) gene expression. It also investigated any correlation between mtDNA copy number and sperm DNA fragmentation (SDF). Sixty-three asthenozoospermic semen samples (Group A) and 63 normokinetic semen samples (Group N) were analysed according to WHO (WHO laboratory manual for the examination and processing of human semen, World Health Organization, Geneva, 2010). Sperm mtDNA copy number and TFAM gene expression were quantified by real time quantitative polymerase chain reaction. SDF was evaluated using the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) assay. The mtDNA copy number was higher in asthenozoospermic semen samples and was negatively correlated with sperm concentration, total sperm number and total motile spermatozoa. The caseload showed a global negative correlation of TFAM gene expression with total motile sperm and a positive correlation with abnormal forms, SDF and mtDNA copy number, but this was not confirmed within each subgroup. SDF was significantly increased in asthenozoospermic samples and correlated with abnormal forms. No correlation was found between SDF and mtDNA copy number. Our results suggest a potential role of mtDNA content as an indicator of semen quality and support the hypothesis that dysregulation of TFAM expression is accompanied by a qualitative impairment of spermatogenesis. Since mtDNA copy number alterations and impaired chromatin integrity could affect reproductive success, these aspects should be evaluated in relation to assisted reproductive techniques.