Sperm DNA damage-the effect of stress and everyday life factors

Exploring the Mechanisms of Yishen Tongluo Decoction on Repairing DNA Damage in Mouse Spermatogonia Cells Based on Whole Transcriptome Sequencing

The aim of this study was to investigate the potential mechanism through which Yishen Tongluo decoction (YSTL) repairs DNA damage caused by benzo(a)pyrene diol epoxide (BPDE) in mouse spermatocytes (GC-2). The GC-2 cells were divided randomly into the control group, BPDE group, and low-, medium-, and high-dose YSTL groups of YSTL decoction. A comet assay was used to detect the DNA fragment index (DFI) of cells in each group. Based on the DFI results, whole transcriptome sequencing was conducted, followed by trend analysis, gene ontology (GO) enrichment analysis, kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis, and ceRNA network analysis. Compared with the control group, the BPDE group reported a significant increase in the DNA fragmentation index (DFI) (p < .05). Compared with the BPDE group, the low-, high- and medium-dose YSTL groups had a significantly reduced DFI (p < .05). Whole-transcriptome sequencing revealed seven differentially expressed circRNAs, 203 differentially expressed miRNAs, and 3,662 differentially expressed mRNAs between the control group and the BPDE group. There was a total of 12 differentially expressed circRNAs, 204 miRNAs, and 2150 mRNAs between the BPDE group and the traditional Chinese medicine group. The pathways involved include DNA repair pathway, nucleotide excision repair pathway, base excision repair pathway, etc. The ceRNA network reported that Hmga2 was the core protein involved, novel_cir_000117 and mmu-miR-466c-3p were located upstream of Hmga2, and they were regulatory factors associated with Hmga2. Finally, we conclude that YSTL decoction may repair sperm DNA damage caused by BPDE through the novel_cir_000117-mmu-miR-466c-3p-Hmga2 pathway.

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.

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.

Epidemiology of sperm DNA fragmentation in a retrospective cohort of 1191 men

BACKGROUND

The scientific and clinical communities now recognize that sperm DNA integrity is crucial for successful fertilization, good embryo development, and offspring quality of life. Despite the apparent unanimity, this criterion is rarely evaluated in clinical practice. We evaluated the sperm DNA fragmentation index of nearly 1200 sperm samples and its connections based on the patient's age, body mass index, the season of sperm collection, geographical location, medical history, and addictive behaviors.

METHODS

A cohort of 1503 patients who were referred to the Royan Institute between July 2018 and March 2020 was examined. Only 1191 patient records with demographic data, complete semen analysis, and DNA fragmentation index measurements were included in the final cohort. Documents were classified, incorporated into statistical models, and analyzed.

RESULTS

The results confirmed previous findings that the sperm DNA fragmentation index was significantly higher in aging men. The sperm DNA fragmentation index and high DNA stainability levels were significantly higher in spring and summer samples than in those of other seasons. No correlation was found between semen DNA fragmentation index and patient body mass index, although the study cohort was significantly overweight. Contrary to what might be expected, we observed that the sperm DNA fragmentation index was higher in rural than in urban patients. Intriguingly, epileptic patients exhibited significantly higher sperm DNA fragmentation index levels.

DISCUSSION AND CONCLUSION

Age is the factor that is most strongly associated with sperm DNA fragmentation index levels. Our analysis of 1191 samples indicates that between the ages of 19 and 59, the sperm DNA fragmentation index increases by an average of 2% each year. Intriguingly, from an epidemiological perspective, the warm season (spring/summer) is associated with a higher sperm DNA fragmentation index in the study population, possibly due to the deleterious effect of temperature on sperm quality. Some neurological diseases, such as epilepsy, are associated with decreased sperm DNA integrity. This observation could be related to the iatrogenic effects of associated therapies. In the study cohort, body mass index did not appear to be correlated with the DNA fragmentation index.

Assessing male gamete genome integrity to ameliorate poor assisted reproductive technology clinical outcome

OBJECTIVE

To assess the role of evaluating sperm chromatin fragmentation (SCF) as a tool to guide treatment in couples who achieved unexpectedly poor clinical outcomes after intracytoplasmic sperm injection (ICSI).

DESIGN

We identified couples with an unexpectedly suboptimal clinical outcome after ICSI who were then screened for SCF. Consequently, the same couples were counseled to undergo a subsequent ICSI cycle using either ejaculates processed by microfluidic sperm selection (MFSS) or spermatozoa retrieved from the testis, and clinical outcomes were compared between history and treatment cycles. To confirm the sole effect of a compromised male gamete, we compared the ICSI outcome in cycles where male gametes with abnormal SCF were used to inseminate autologous and donor oocytes. Finally, to eliminate an eventual confounding female factor component, we compared the clinical outcome of ICSI cycles using sibling donor oocytes injected with spermatozoa with normal or abnormal SCF.

SETTING

Academic reproductive medicine center point of care.

PATIENT(S)

The patient population consisted of 76 couples with reproductively healthy and relatively young female partners and male partners with compromised semen parameters, but suitable for ICSI. In a subanalysis, we identified 67 couples with abnormal SCF who underwent ICSI cycle(s) with donor oocytes. Furthermore, we identified 29 couples, 12 with normal SCF and 17 with abnormal, uncorrected SCF, and 7 couples with abnormal, corrected SCF vs. a control, who used sibling donor oocytes for their ICSI cycle(s).

INTERVENTION(S)

For couples who resulted in surprisingly low clinical outcomes after ICSI, despite semen parameters adequate for ICSI and a normal female infertility evaluation, a SCF assessment was performed on the semen specimen using the terminal deoxynucleotidyl transferase-mediated fluorescein-deoxyuridine triphosphate nick-end labeling (TUNEL) assay. The couples then underwent a subsequent ICSI cycle with spermatozoa processed by MFSS or surgically retrieved. Moreover, cycles with donor oocytes were used to confirm the sole contribution of the male gamete.

MAIN OUTCOME MEASURE(S)

Clinical outcomes, such as fertilization, embryo implantation, clinical pregnancy, delivery, and pregnancy loss rates were compared between history and treatment cycle(s) using ejaculated spermatozoa selected by MFSS or from a testicular biopsy, taking into consideration the level of SCF. In a subanalysis, we reported the clinical outcomes of 67 patients who used donor oocytes and compared them with cycles where their own oocytes were used. Furthermore, we compared the ICSI clinical outcomes between cycles using sibling donor oocytes injected with low or high SCF with or without sperm intervention aimed at correcting, or alleviating the degree of SCF.

RESULT(S)

In a total of 168 cycles, 76 couples had in a prior cycle a 67.1% fertilization rate, and clinical pregnancy and pregnancy loss rates of 16.6% and 52.3%, respectively. After testing for SCF, the DNA fragmentation rate was 21.6%. This led to a subsequent ICSI cycle with MFSS or testicular sperm extraction, resulting in clinical pregnancy and delivery rates of 39.2%, and 37.3%, respectively. The embryo implantation rate increased to 23.5%, whereas the pregnancy loss rate decreased to 5% in the treatment cycle. This was particularly significant in the moderate SCF group, reaching embryo implantation, clinical pregnancy, and delivery rates of 24.3%, 40.4%, and 36.2%, respectively, and reducing the pregnancy loss rate to 10.5% in post-sperm treatment cycles. In 67 patients with high SCF who used donor oocytes, a significantly higher fertilization rate of 78.1% and embryo implantation rate of 29.1% were reported, compared with those in couples also with an elevated SCF who used their own. Interestingly, the clinical pregnancy and delivery rates only increased slightly from 28.0%-36.1% and from 23.7%-29.2%, respectively. To further control for a female factor, we observed couples who shared sibling donor oocytes, 17 with normal SCF and 12 with abnormal (uncorrected) SCF. Interestingly, the abnormal SCF group had impaired fertilization (69.3%), embryo implantation (15.0%), and delivery (15.4%) rates. For an additional 15 couples who split their donor oocytes, 8 had normal SCF, and although 7 couples originally had abnormal SCF, 4 used microfluidic processing, 2 used testicular spermatozoa, and 1 used donor spermatozoa to alleviate the degree of SCF, resulting in comparable clinical outcomes with the normal SCF group.

CONCLUSION(S)

A superimposed male factor component may explain the disappointing ICSI outcome in some couples despite reproductively healthy female partners. Therefore, it may be useful to screen couples for SCF to guide treatment options and maximize chances of a successful pregnancy. The improved, but suboptimal pregnancy and delivery outcomes observed in couples using donor oocytes confirmed the exclusive detrimental role that the male gamete exerted on embryo development despite the presence of putative oocyte repair mechanisms.

Lifestyle, Insulin Resistance and Semen Quality as Co-Dependent Factors of Male Infertility

Infertility is a problem that affects millions of couples around the world. It is known as a disease of couples, not individuals, which makes diagnosis difficult and treatment unclear. Male infertility can have many causes, from mechanical ones to abnormal spermatogenesis or spermiogenesis. Semen quality is determined by a number of factors, including those dependent on men themselves, with the number of infertile men growing every year. These include, e.g., diet, physical activity, sleep quality, stress, among many others. As these factors co-exist with insulin resistance, which is a disease closely related to lifestyle, it has been singled out in the study due to its role in affecting semen quality. In order to examine connections between lifestyle, insulin resistance, and semen quality, a review of literature published from 1989 to 2020 in the following databases PubMed/Medline, EMBASE (Elsevier), Scopus, Web of Science, and Google Scholar was performed. Hence, semen quality, environment, and insulin resistance are interrelated, thus it is difficult to indicate which aspect is the cause and which is the effect in a particular relationship and the nature of possible correlations. Since the influence of lifestyle on semen quality has been extensively studied, it is recommended that more thorough research be done on the relationship between insulin resistance and semen quality, comparing the semen quality of men with and without insulin resistance.

Sperm Cryopreservation Outcomes in Transgender Adolescents Compared with Adolescents Receiving Gonadotoxic Therapy

Purpose

The target population for fertility preservation recently has been expanded from adolescents with cancer undergoing gonadotoxic chemotherapy to include transgender youth before initiating gender-affirming hormone therapy. Patients and providers may have knowledge deficits regarding options for fertility preservation, accessibility, and feasibility of its techniques, and impact of treatment on future fertility. This study describes outcomes of sperm cryopreservation in transgender male-to-female (affirmed female) youth and compares semen parameters with adolescents diagnosed with cancer.

Methods

Medical records of transgender-affirmed female adolescents and adolescent males diagnosed with cancer who underwent sperm cryopreservation at the Fertility and Advanced Reproductive Medicine clinic of the University of Texas (UT) Southwestern Medical Center between March 2015 and March 2020 were reviewed. Demographic data were recorded and values for sperm parameters (volume, count, total count, motility (%), total motile) were collected. When available, hormone levels (luteinizing hormone, follicle-stimulating hormone, testosterone, and estradiol) and Tanner stages were also assessed. The two populations were compared using chi-square analysis and two-sample student's t-test. Data are presented as mean±standard deviation.

Results

While semen quality parameters trended lower in transgender youth compared with adolescents with cancer, there was no statistically significant difference between groups. While four out of 18 patients in the transgender group had azoospermia, mean semen quality parameters fell within normal adult reference ranges for both groups.

Conclusion

Sperm cryopreservation for transgender youth and adolescents with cancer is feasible, inexpensive, and does not result in significant treatment delays. This information can improve counseling and access to these procedures, particularly in the transgender population.

Effect of Stress and Caffeine on Male Infertility

Caffeine is a natural psychoactive chemical found in beverages made from coffee. In addition, it is added by the manufacturers of a large number of sodas and energy drinks. It does this by stimulating both the brain and the central nervous system, enabling you to avoid being sleepy while still keeping you attentive. A state of emotional or physical tension is defined as stress. It can be induced through the experience of something or thinking of something that causes you to feel uncomfortable, irritated, or nervous. Your body's response to adversity or demand is what we call stress. Among couples, male infertility is common. A failure in spermatogenesis is accountable for nearly half of all occurrences of infertility in marriage. Ageing, psychological stress, diet, physical exercise, coffee, hot water, hot scrotum, and cell phone usage are some of the few modifiable lifestyle variables that have a role in the development of infertility. Many hypotheses have been proposed to establish the link between stress in the workplace, life events (war, earthquake, etc.), and inability to conceive have been linked to inferior or degraded semen quality. In this review, we will discuss the effect on male fertility of elements including quality of life (such as exercise, diet, and other alterations to one's daily routine) and psychological stress. In addition, the effects on male fertility of elevated scrotal temperature, improper dietary habits, and physical inactivity will be discussed. The loss in male fertility, mainly due to ageing, inappropriate lifestyles, and environmental factors, is a significant public health concern in this century. Couples can enhance their quality of life and increase their chances of naturally conceiving a child by altering their way of life and supplementing it with nutraceutical antioxidants and an organised educational, environmental, dietary, and physical exercise program.

Addiction and human male fertility: A systematic review and a critical appraisal

BACKGROUND

Addiction is a global problem that has many negative consequences on human health as well as the quality of life.

OBJECTIVES

This review aimed to assess the effect of addiction on human male fertility.

METHODS

A systematic review was conducted on various electronic sites.

RESULTS

The initial literature search identified a total of 5239 articles in all searched databases. After removing duplicates and application of inclusion/exclusion criteria,177 were potential articles, 112 were omitted because no direct relevance was encountered. Finally, 65 studies were retained for review. They were classified according to the type of addiction into; opioids and cannabinoids (18 articles), alcohol (7 articles), cocaine (2 articles), Androgenic Anabolic steroids AAS (15 articles), tobacco (10 articles) and caffeine (13 articles). Most of these recruited articles demonstrated a negative impact of the addressed substance on male fertility with variable levels of evidence.

CONCLUSIONS

It was concluded that addiction harms human male fertility that should be put into consideration. More future studies are needed after a proper methodological and statistical approach, including logistic regression analysis, to predict the effect of a specific substance on human male fertility. This article is protected by copyright. All rights reserved.

Cigarette heavy smoking alters DNA methylation patterns and gene transcription levels in humans spermatozoa

Tobacco smoking is considered the most common reason of death and infertility around the world. This study was designed to assess the impact of tobacco heavy smoking on sperm DNA methylation patterns and to determine whether the transcription level of ALDH3B2, PTGIR, PRICKLE2, and ALS2CR12 genes is different in heavy smokers compared to non-smokers. As a screening study, the 450 K array was used to assess the alteration in DNA methylation patterns between heavy smokers (n = 15) and non-smokers (n = 15). Then, four CpGs that have the highest difference in methylation level (cg16338278, cg08408433, cg05799088, and cg07227024) were selected for validation using deep bisulfite sequencing in an independent cohort of heavy smokers (n = 200) and non-smokers (n = 100). A significant variation was found between heavy smokers and non-smokers in the methylation level at all CpGs within the PRICKLE2 and ALS2CR12 gene amplicon (P < 0.001). Similarly, a significant variation was found in the methylation level at nine out of thirteen CpGs within the ALDH3B2 gene amplicon (P < 0.01). Additionally, eighteen CpGs out of the twenty-six within the PTGIR gene amplicon have a significant difference in the methylation level between heavy smokers and non-smokers (P < 0.01). The study showed a significant difference in sperm global DNA methylation, chromatin non-condensation, and DNA fragmentation (P < 0.001) between heavy smokers and non-smokers. A significant decline was shown in the transcription level of ALDH3B2, PTGIR, PRICKLE2, and ALS2CR12 genes (P < 0.001) in heavy smokers. In conclusion, heavy smoking influences DNA methylation at several CpGs, sperm global DNA methylation, and transcription level of the PRICKLE2, ALS2CR12, ALDH3B2, and PTGIR genes, which affects negatively the semen parameters of heavy smokers.

Exposure to polycyclic aromatic hydrocarbons and nicotine, and associations with sperm DNA fragmentation

Background

Tobacco smoking has been reported to cause DNA fragmentation and has been suggested to cause mutations in spermatozoa. These effects have been ascribed to the action of polycyclic aromatic hydrocarbons (PAH) present in the smoke. Simultaneously, DNA fragmentation has been associated with mutagenesis.

Objective

The aim of this study was to investigate whether levels of urinary biomarkers of PAH and nicotine exposure were associated with sperm DNA fragmentation.

Methods

In the urine of 381 men recruited from two cohorts of young men (17–21 years old) from the general Swedish population, the PAH metabolites 1‐hydroxypyrene and 2‐hydroxyphenanthrene, as well as the nicotine metabolite cotinine, were measured. The sperm DNA fragmentation index (DFI) was analysed using the sperm chromatin structure assay. Associations between the DFI, and PAH metabolite levels as continuous variables as well as in quartiles, were studied by general linear models adjusted for abstinence time. A similar analysis was carried out for cotinine levels, according to which the men were categorised as “non‐smoking” (n = 216) and “smoking” (n = 165).

Results

No association was found between levels of any of the three biomarkers and DFI, either as a continuous variable (p = 0.87–0.99), or when comparing the lowest and the highest quartiles (p = 0.11–0.61). The same was true for comparison of men categorised as non‐smoking or smoking (DFI 11.1% vs. 11.8%, p = 0.31).

Discussion

We found no evidence of PAH or nicotine exposure to be associated with DFI, which does not exclude that these exposures may have other effects on sperm DNA.

Conclusion

In these young men, levels of biomarkers of nicotine and PAH exposure were not associated with DFI.

The detrimental effect of cell phone radiation on sperm biological characteristics in normozoospermic

Radiofrequency electromagnetic radiation emitted from cell phone has harmful effects on some organs of the body, such as the brain, heart, and testes. This study aimed to assess the effects of cell phones on sperm parameters, DNA fragmentation, and apoptosis in normozoospermic. Normal sperm samples were divided into two groups of control and case. The samples from the case were placed for 60 min at a distance of approximately 2.5 cm from the cell phone set in the active antenna position. Control samples were exposed to cell phones without active antennas. All specimens were analysed by World Health Organization criteria. Sperm viability, sperm with chromatin abnormality and maturity, DNA fragmentation, and apoptosis were examined. Viability and motility in the case were significantly lower than the control (p < .001, p = .004 respectively). The percentage of apoptotic sperms and DNA fragmentation were significantly higher in the case when compared with the control (p = .031, p < .001 respectively). The other parameters studied such as morphology, chromatin abnormality, and maturity showed no significant difference between the case and control groups. Cell phone waves had a detrimental effect on human sperm's biological features. Therefore, it is recommended to keep the cell phone away from the pelvis as much as possible.

Effect of paternal health on pregnancy loss-A review of current evidence

Pregnancy loss has multifactorial causes, and the maternal risk factors are the most investigated. Therefore, this review investigates the current literature regarding the effect of paternal health on pregnancy loss. This review is conducted according to the PRISMA guidelines. The electronic databases PubMed and Medline were the primary sources of information. The online tool covidence.org was used for the screening process. The Newcastle-Ottawa Scale was used for assessment of risk of bias across the non-RCT (Randomized Controlled Trials) included studies. Six cohort studies and one randomised clinical trial were included for assessment in this review. Especially three large retrospective studies reported that circulatory paternal health issue, increasing metabolic syndrome diagnoses and paternal age was significantly associated with a higher risk of pregnancy loss. Lower pregnancy loss was also found in couples with diabetes in the man compared to couples without diabetes. One study suggests a connection between varicocelectomy and improved sperm DNA fragmentation and lower abortion rate. This review confirms that paternal age, somatic health and particularly health regarding cardiovascular and metabolic disease are associated positively with risks of pregnancy loss. However, further research may lead to evidence, which are more conclusive.

The Effect of Daily Intake of Selenium, Vitamin E and Folic Acid on Sperm Parameters in Males with Idiopathic Infertility: A Single-Blind Randomized Controlled Clinical Trial

Background

Male infertility may originate from a wide spectrum of conditions while in 30-40 percent of cases, no significant reason can be identified. Thereby, it is recognized as male idiopathic infertility. This study was undertaken to investigate the effect of daily intake of selenium, vitamin E and folic acid on sperm parameters in males with idiopathic infertility.

Materials and Methods

Seventy infertile men were selected to participate in this single-blind, randomized controlled clinical trial using convenience sampling. They were equally divided into two groups via permuted block randomization method. The intervention group received selenium tablet (200 μg per day, oral), vitamin E capsule (400 IU per day, oral) and folic acid tablet (5 mg per day, oral).The placebo group received matching placebo for three months. Semen volume, total sperm motility, sperm concentration, progressive sperm motility, normal sperm morphology, sperm motility index (SMI) and functional sperm concentration (FSC) were assessed by sperm quality analyzer-v (SQAV) before and after the intervention. Paired t test, and independent t test were used to compare the results within and between the groups, respectively. The IBM SPSS V.16.005 was used for data analysis. A P<0.05 was considered statistically significant.

Results

After three months, according to within-group analysis, a significant difference was found in mean SMI (P=0.007) and FSC (P=0.001) in the intervention group. According to between-group analysis, no significant difference was found in mean semen volume (P=0.610), sperm concentration (P=0.126), total sperm motility (P=0.765), progressive sperm motility (P=0.767), normal sperm morph (P=0.403), SMI (P=0.556) or FSC (P=0.706) between the groups.

Conclusion

Consumption of selenium, vitamin E and folic acid in infertile men with asthenozoospermia was not effective (Registration number: IRCT2017012432153N1).

Oxidation of Sperm DNA and Male Infertility

One important reason for male infertility is oxidative stress and its destructive effects on sperm structures and functions. The particular composition of the sperm membrane, rich in polyunsaturated fatty acids, and the easy access of sperm DNA to oxidative damage due to sperm cell specific cytologic and metabolic features (no cytoplasm left and cells unable to mount stress responses) make it the cell type in metazoans most susceptible to oxidative damage. In particular, oxidative damage to the spermatozoa genome is an important issue and a cause of male infertility, usually associated with single- or double-strand paternal DNA breaks. Various methods of detecting sperm DNA fragmentation have become important diagnostic tools in the prognosis of male infertility and such assays are available in research laboratories and andrology clinics. However, to date, there is not a clear consensus in the community as to their respective prognostic value. Nevertheless, it is important to understand that the effects of oxidative stress on the sperm genome go well beyond DNA fragmentation alone. Oxidation of paternal DNA bases, particularly guanine and adenosine residues, the most sensitive residues to oxidative alteration, is the starting point for DNA damage in spermatozoa but is also a danger for the integrity of the embryo genetic material independently of sperm DNA fragmentation. Due to the lack of a spermatozoa DNA repair system and, if the egg is unable to correct the sperm oxidized bases, the risk of de novo mutation transmission to the embryo exists. These will be carried on to every cell of the future individual and its progeny. Thus, in addition to affecting the viability of the pregnancy itself, oxidation of the DNA bases in sperm could be associated with the development of conditions in young and future adults. Despite these important issues, sperm DNA base oxidation has not attracted much interest among clinicians due to the lack of simple, reliable, rapid and consensual methods of assessing this type of damage to the paternal genome. In addition to these technical issues, another reason explaining why the measurement of sperm DNA oxidation is not included in male fertility is likely to be due to the lack of strong evidence for its role in pregnancy outcome. It is, however, becoming clear that the assessment of DNA base oxidation could improve the efficiency of assisted reproductive technologies and provide important information on embryonic developmental failures and pathologies encountered in the offspring. The objective of this work is to review relevant research that has been carried out in the field of sperm DNA base oxidation and its associated genetic and epigenetic consequences.

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.

PICSI vs. MACS for abnormal sperm DNA fragmentation ICSI cases: a prospective randomized trial

PURPOSE

To know which sperm selection technique, physiological intracytoplasmic sperm injection (PICSI) or magnetic-activated cell sorting (MACS), is better for the selection of sperm with abnormal sperm DNA fragmentation (SDF) in patients undergoing intracytoplasmic sperm injection (ICSI).

METHODS

A prospective randomized trial included 413 ICSI cases with abnormal SDF (> 20.3%) by TUNEL assay. Patients with at least 1 million total progressive motile sperm count were randomized to PICSI or MACS groups on the day of ICSI. PICSI depends on the hyaluronan binding of better SDF sperm where individual sperm was selected, while MACS selects non-apoptotic sperm population using Annexin V magnetic beads. All pre-implantation embryogenic parameters were observed and the main outcome was the ongoing pregnancy rate.

RESULTS

There were no significant differences between patients allocated to PICSI and MACS in the studied parameters including pre-implantation embryological data, implantation, clinical pregnancy, and ongoing pregnancy rates. Meanwhile, sub-analysis according to the female age has shown that female patients with less than 30 years of age in the MACS group had significantly higher good-quality blastocyst, clinical pregnancy, and ongoing pregnancy rates than the PICSI group. However, the higher implantation (p = 0.051), clinical pregnancy (p = 0.078), and ongoing pregnancy (p = 0.097) rates observed in females between 30 and 35 years of age in the PICSI group did not reach significance level.

CONCLUSIONS

PICSI and MACS are efficient techniques for sperm selection in cases with abnormal sperm DNA fragmentation. However, MACS is preferred when the females are younger than 30 years, while PICSI is preferred in older females.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03398317 (retrospectively registered).

The effect of modifiable lifestyle factors on semen quality

INTRODUCTION AND OBJECTIVES

To examine the association between lifestyle factors (body mass index, smoking, alcohol consumption, coffee intake, physical activity, sauna and cell phone usage, wearing tight-fitting underwear), and conventional semen parameters.

MATERIALS AND METHODS

1311 participants who attended the Andrology Clinic were included in the study. All participants were separated into two groups as men with normozoospermia and dysspermia. All participants answered a questionnaire which contains questions about the modifiable lifestyle factors. The total risk scores were calculated after all the positive lifestyle factors had been counted.

RESULTS

Men with normozoospermia and dysspermia consisted of 852 (65.0%) and 459 (35.0%) participants respectively. A negative relationship between the wearing of tight underwear and having normal semen parameters was detected between the two groups (p=0.004). While going to a sauna regularly was negatively related to semen concentration, wearing tight underwear was also related to both lower motility, normal morphology as well as semen concentration (p<0.05). While the total score of all participants was 5.22±1.34 point, there were no statistical differences between the two groups (p=0.332). It was found that having 3 more or fewer points was not related to any type of semen parameters and results of a spermiogram.

CONCLUSION

The clinicians should give advice to infertile male patients about changing their risky lifestyle, for infertility, to a healthy lifestyle for fertility. Better designed studies, with larger sample sizes using conventional semen analysis with sperm DNA analysis methods, should be planned to identify the possible effects of lifestyle factors on semen quality.

The current status and future of andrology: A consensus report from the Cairo workshop group

BACKGROUND

In attempting to formulate potential WHO guidelines for the diagnosis of male infertility, the Evidence Synthesis Group noted a paucity of high-quality data on which to base key recommendations. As a result, a number of authors suggested that key areas of research/evidence gaps should be identified, so that appropriate funding and policy actions could be undertaken to help address key questions.

OBJECTIVES

The overall objective of this Consensus workshop was to clarify current knowledge and deficits in clinical laboratory andrology, so that clear paths for future development could be navigated.

MATERIALS AND METHODS

Following a detailed literature review, each author, prior to the face-to-face meeting, prepared a summary of their topic and submitted a PowerPoint presentation. The topics covered were (a) Diagnostic testing in male fertility and infertility, (b) Male fertility/infertility in the modern world, (c) Clinical management of male infertility, and (d) The overuse of ICSI. At the meeting in Cairo on February 18, 2019, the evidence was presented and discussed and a series of consensus points agreed.

RESULTS

The paper presents a background and summary of the evidence relating to these four topics and addresses key points of significance. Following discussion of the evidence, a total of 36 consensus points were agreed.

DISCUSSION

The Discussion section presents areas where there was further debate and key areas that were highlighted during the day.

CONCLUSION

The consensus points provide clear statements of evidence gaps and/or potential future research areas/topics. Appropriate funding streams addressing these can be prioritized and consequently, in the short and medium term, answers provided. By using this strategic approach, andrology can make the rapid progress necessary to address key scientific, clinical, and societal challenges that face our discipline now and in the near future.

Impact of Weight Loss Strategies on Obesity-Induced DNA Damage

SCOPE

Obesity causes DNA damage, which is causally related to several disorders including cancer, infertility, and cognitive dysfunctions. The aim of this study is to investigate whether weight loss improves the integrity of the genetic material.

METHODS AND RESULTS

Overweight mice are fed ad libitum either with a Western diet (WD), with a 40% caloric restricted WD, or with a high carbohydrate low protein (HCLP) diet. Caloric restriction and also the HCLP diet lead to ca. 30% weight loss, which is paralleled by decreased DNA damage ("comet" formation) and oxidative damage of purines in inner organs, additionally the activity of nucleotide excision repair increased. The effects are more pronounced in animals that have received the HCLP chow. Results of biochemical analyses indicate that the reduction of DNA damage is associated with a decrease of pro-inflammatory cytokines and lower insulin levels.

CONCLUSION

The study indicates that weight loss may prevent obesity-associated adverse health effects due to reduction of overall DNA damage.

Linking sleep disturbance to idiopathic male infertility

Recently published data suggests that male fertility has declined over the past four decades. The reasons for the decline are unclear with up to 50% of cases of male infertility remaining unexplained (idiopathic male infertility). Whilst environmental factors and rising rates of obesity have been implicated, there is now growing evidence that sleep disturbance may be an independent causative factor. Indeed, the prevalence of sleep disturbance appears to be increasing in parallel with deterioration in population sperm quality, a commonly used surrogate marker of male fertility. Although there is some understanding of the relationship between sleep, gonadal hormone secretion and sexual function, it remains to be seen whether sleep disturbance is implicated in idiopathic male infertility. This review will detail the current evidence supporting a link between sleep disturbance and male infertility. Potential mechanistic pathways will be proposed and evidence supporting these pathways will be discussed. Further research is needed in clarifying links between sleep disturbance and idiopathic male infertility. At present the only available treatment option for men with idiopathic infertility is assisted reproductive technology. Demonstration of a causative link between sleep disturbance and idiopathic male infertility may in the future lead to additional treatment options in selected cases.

Gallic acid, a common dietary phenolic protects against high fat diet induced DNA damage

Purpose

Aim of the study was to find out if gallic acid (GA), a common phenolic in plant foods, prevents obesity induced DNA damage which plays a key role in the induction of overweight associated cancer.

Methods

Male and female C57BL6/J mice were fed with a low fat or a high fat diet (HFD). The HFD group received different doses GA (0, 2.6–20 mg/kg b.w./day) in the drinking water for 1 week. Subsequently, alterations of the genetic stability in blood and inner organs were monitored in single cell gel electrophoresis assays. To elucidate the underlying molecular mechanisms: oxidized DNA bases, alterations of the redox status, lipid and glucose metabolism, cytokine levels and hepatic NF-κB activity were monitored.

Results

HFD fed animals had higher body weights; increased DNA damage and oxidation of DNA bases damage were detected in colon, liver and brain but not in blood and white adipose tissue. Furthermore, elevated concentrations of insulin, glucose, triglycerides, MCP-1, TNF-α and NF-κB activity were observed in this group. Small amounts of GA, in the range of human consumption, caused DNA protection and reduced oxidation of DNA bases, as well as biochemical and inflammatory parameters.

Conclusions

Obese animals have increased DNA damage due to oxidation of DNA bases. This effect is probably caused by increased levels of glucose and insulin. The effects of GA can be explained by its hypoglycaemic properties and indicate that the consumption of GA-rich foods prevents adverse health effects in obese individuals.

Electronic supplementary material

The online version of this article (10.1007/s00394-018-1782-2) contains supplementary material, which is available to authorized users.

Impact of obesity and overweight on DNA stability: Few facts and many hypotheses

Health authorities are alarmed worldwide about the increase of obesity and overweight in the last decades which lead to adverse health effects including inflammation, cancer, accelerated aging and infertility. We evaluated the state of knowledge concerning the impact of elevated body mass on genomic instability. Results of investigations with humans (39 studies) in which DNA damage was monitored in lymphocytes and sperm cells, are conflicting and probably as a consequence of heterogeneous study designs and confounding factors (e.g. uncontrolled intake of vitamins and minerals and consumption of different food types). Results of animal studies with defined diets (23 studies) are more consistent and show that excess body fat causes DNA damage in multiple organs including brain, liver, colon and testes. Different molecular mechanisms may cause genetic instability in overweight/obese individuals. ROS formation and lipid peroxidation were found in several investigations and may be caused by increased insulin, fatty acid and glucose levels or indirectly via inflammation. Also reduced DNA repair and formation of advanced glycation end products may play a role but more data are required to draw firm conclusions. Reduction of telomere lengths and hormonal imbalances are characteristic for overweight/obesity but the former effects are delayed and moderate and hormonal effects were not investigated in regard to genomic instability in obese individuals. Increased BMI values affect also the activities of drug metabolizing enzymes which activate/detoxify genotoxic carcinogens, but no studies concerning the impact of these alterations of DNA damage in obese individuals are available. Overall, the knowledge concerning the impact of increased body weight and DNA damage is poor and further research is warranted to shed light on this important issue.

Shortened daily photoperiod during the non-breeding season can improve the reproductive performance of camel bulls (Camelus dromedarius)

The effects of a shortened photoperiod on the reproductive performance and hormones of mature dromedary camel bulls (Camelus dromedarius) were evaluated. A group of 6 bulls were blindfolded to induce a daily photoperiod that was ∼2.55 h shorter than the natural day length (10.83L:13.17D), whereas 6 others served as the control group. The trial started in June and continued for 10 weeks during the non-breeding season. The reproductive performance of all animals was evaluated weekly during this time and also during the breeding season, starting in December and continuing for 10 weeks. Camel bulls in the treatment group showed a significant (p < 0.05) increase in testicular volume, scrotal circumference, sexual desire, reaction time, and mating ability scores, and serum melatonin and testosterone concentrations, relative to the control group, during the non-breeding season. In addition, sexual desire and reaction time and mating ability scores were significantly (p < 0.05) higher in the treatment group than in the control during the breeding season. There was no significant difference between the treatment groups in both seasons and the control group in the breeding season regarding semen volume, sperm cell concentration, total motility, progressive motility, plasma membrane integrity, and viability. Shortening the daily photoperiod by blindfolding can improve the reproductive performance of dromedary camel bulls during the non-breeding season and the following breeding season. This simple, inexpensive, and easily applicable method can enable breeders to collect semen of acceptable quality during the non-breeding season.

Impact of weight loss on sperm DNA integrity in obese men

The objective of the study was to determine whether weight loss in obese men improves their fertility with respect to DNA fragmentation index and morphology. Collected fertility parameters included DFI and morphology. Body mass index (BMI) was calculated for all patients with comparisons to their fertility parameters before and after weight loss using paired t test and chi-square tests. The mean BMI was significantly higher in group 1, before weight loss (33.18 kg/m2 ), than in group 2, after weight loss (30.43 kg/m2 ). Overall, 53.3% of men had DFI <20% while 43.8% had a DFI between 20% and 40%, and 2.9% of men had DFI >40%. The mean DFI of participants was higher before weight loss (20.2%) and had improved significantly after weight loss (17.5%) (p = <.001). The weight loss had significant positive correlation with percentage of DFI. There was a significant improvement in morphology after weight loss (p = <.05). In one of the largest cohorts of male fertility and obesity, DFI and morphology demonstrated significant relationship with adiposity, possibly contributing to subfertility in this population.

[Environment and lifestyle: Impacts on male fertility?]

In this last century, an increase of men infertility has been registered. It has been suggested that environmental factors could a negative impact over sperm quality. Among these factors, impact of environmental toxicant has been spread by media. In this review of scientific literature, we identify several environmental factors that could impact men fertility in a negative way. These factors are tobacco, marijuana, weight, body mass index, heat, nutritional state, electromagnetic waves and altitude. For each of these factors, the impact over men fertility, their mechanism, as well their influence over the use of Assisted Reproductive Technics are reported.

Coffee and caffeine intake and male infertility: a systematic review

BACKGROUND

Semen quality, a predictor of male fertility, has been suggested declining worldwide. Among other life style factors, male coffee/caffeine consumption was hypothesized to influence semen parameters, but also sperm DNA integrity. To summarize available evidence, we performed a systematic review of observational studies on the relation between coffee/caffeine intake and parameters of male fertility including sperm ploidy, sperm DNA integrity, semen quality and time to pregnancy.

METHODS

A systematic literature search was performed up to November 2016 (MEDLINE and EMBASE). We included all observational papers that reported the relation between male coffee/caffeine intake and reproductive outcomes: 1. semen parameters, 2. sperm DNA characteristics, 3. fecundability. All pertinent reports were retrieved and the relative reference lists were systematically searched in order to identify any potential additional studies that could be included.

RESULTS

We retrieved 28 papers reporting observational information on coffee/caffeine intake and reproductive outcomes. Overall, they included 19,967 men. 1. Semen parameters did not seem affected by caffeine intake, at least caffeine from coffee, tea and cocoa drinks, in most studies. Conversely, other contributions suggested a negative effect of cola-containing beverages and caffeine-containing soft drinks on semen volume, count and concentration. 2. As regards sperm DNA defects, caffeine intake seemed associated with aneuploidy and DNA breaks, but not with other markers of DNA damage. 3. Finally, male coffee drinking was associated to prolonged time to pregnancy in some, but not all, studies.

CONCLUSIONS

The literature suggests that caffeine intake, possibly through sperm DNA damage, may negatively affect male reproductive function. Evidence from epidemiological studies on semen parameters and fertility is however inconsistent and inconclusive. Well-designed studies with predefined criteria for semen analysis, subject selection, and life style habits definition, are essential to reach a consistent evidence on the effect of caffeine on semen parameters and male fertility.