Oxidative DNA Damage to Sperm Cells and Peripheral Blood Leukocytes in Infertile Men

Biomarkers of oxidative stress and reproductive complications

Oxidative stress is the result of an imbalance between the formation of reactive oxygen species (ROS) and the levels of enzymatic and non-enzymatic antioxidants. The assessment of biological redox status is performed by the use of oxidative stress biomarkers. An oxidative stress biomarker is defined as any physical structure or process or chemical compound that can be assessed in a living being (in vivo) or in solid or fluid parts thereof (in vitro), the determination of which is a reproducible and reliable indicator of oxidative stress. The use of oxidative stress biomarkers allows early identification of the risk of developing diseases associated with this process and also opens up possibilities for new treatments. At the end of the last century, interest in oxidative stress biomarkers began to grow, due to evidence of the association between the generation of free radicals and various pathologies. Up to now, a significant number of studies have been carried out to identify and apply different oxidative stress biomarkers in clinical practice. Among the most important oxidative stress biomarkers, it can be mentioned the products of oxidative modifications of lipids, proteins, nucleic acids, and uric acid as well as the measurement of the total antioxidant capacity of fluids in the human body. In this review, we aim to present recent advances and current knowledge on the main biomarkers of oxidative stress, including the discovery of new biomarkers, with emphasis on the various reproductive complications associated with variations in oxidative stress levels.

The activated ATM/AMPK/mTOR axis promotes autophagy in response to oxidative stress-mediated DNA damage co-induced by molybdenum and cadmium in duck testes

Cadmium (Cd) and excess molybdenum (Mo) have multiple organ toxicity, and testis is one of their important target organs, but the reproductive toxicity of Mo and Cd combined treatment is still unclear. To explore the effects of Mo and Cd co-exposure on DNA damage and autophagy from the insight of ATM/AMPK/mTOR axis in duck testes, we randomly assigned 40 healthy 8-day-old ducks to control, Mo (100 mg/kg Mo), Cd (4 mg/kg Cd), and Mo + Cd groups for 16 weeks. Results found that Mo and/or Cd exposure caused trace elements imbalance, oxidative stress with a decrease in the activities of GSH-Px, CAT, T-SOD and GSH content, an increase in the concentrations of H₂O₂ and MDA and pathological damage. Additionally, Mo and/or Cd markedly raised DNA damage-related factors expression levels and 8-OHdG content, caused G1/S arrest followed by decreasing CDK2 and Cyclin E protein levels and increasing CDK1 and Cyclin B protein levels, and activated ATM/AMPK/mTOR axis by enhancing p-ATM/ATM, p-AMPK/AMPK and reducing p-mTOR/mTOR protein levels, eventually triggered autophagy by elevating LC3A, LC3B, Atg5, Beclin-1 mRNA levels and LC3II/LC3I, Beclin-1 protein levels and reducing P62, Dynein, mTOR mRNA levels and P62 protein level. Moreover, these changes were most apparent in the combined group. Altogether, the results reveal that autophagy caused by Mo and/or Cd may be associated with activating the DNA damage-mediated ATM/AMPK/mTOR axis in duck testes, and Mo and Cd co-exposure exacerbates these changes.

Correlation between reproductive hormones levels and semen quality in patients with diabetes

Diabetes mellitus (DM) is rarely sought among infertile patients due to a lack of studies and inconsistency regarding its impact on semen quality. This cross-sectional study aimed to determine the influence of T2DM on the pituitary gland hormones (FSH and LH) in males. A total of 60 participants participated in this study, of which 35 were diagnosed with diabetes mellitus, and 25 were without diabetes. Fasting blood sugar, HbA1c, LH, FSH, TT, E2, and prolactin were tested. Diabetic men had lower serum LH, FSH, and TT levels than non-diabetics and higher prolactin and E2 levels. According to the semen examination, including sperm count, PH, motility, and morphology, diabetic patients had considerably lower sperm counts, motility, and morphology than non-diabetic patients. In conclusion, the decrease in the concentration of reproductive hormones in diabetic patients leads to sexual weakness, resulting in abnormal seminal fluid parameters, which are below the normal levels than in apparently healthy persons.

Impact of heavy alcohol consumption and cigarette smoking on sperm DNA integrity

The purposes of the presents study were to investigate the impact of alcohol consumption and cigarette smoking on semen parameters and sperm DNA quality, as well as to determine whether tobacco smoking, or alcohol consumption causes more deterioration of sperm quality. Two hundred and eleven semen samples of men were included in this study. Four groups were studied: heavy smokers (N = 48), heavy drinkers (N = 52), non-smokers (n = 70), and non-drinkers (n = 41). Semen parameters were determined according to WHO guidelines, protamine deficiency assessed by chromomycin (CMA3) staining, and sperm DNA fragmentation (sDF) evaluated by TUNEL assay. Sperm parameters were significantly higher in non-smokers versus smokers and in non-drinkers versus drinkers (p < 0.005). However, protamine deficiency and sDF were significantly lower in non-smokers versus smokers and in non-drinkers versus drinkers (p < 0.0001). No significant difference in the semen analysis parameters was observed between heavy smokers and heavy drinkers (semen volume: 3.20 ± 1.43 vs. 2.81 ± 1.56 ml, semen count: 65.75 ± 31.32 vs. 53.51 ± 32.67 mill/ml, total motility: 24.27 ± 8.18 vs. 23.75 ± 1.75%, sperm vitality: 36.15 ± 18.57 vs. 34.62 ± 16.65%, functional integrity: 41.56 ± 18.57 vs. 45.96 ± 17.98% and the morphologically normal spermatozoa: 28.77 ± 11.82 vs. 27.06 ± 13.13%, respectively). However, protamine deficiency was significantly higher among drinkers than smokers (37.03 ± 9.75 vs. 33.27 ± 8.56%, p = 0.020). The sDF was also significantly higher among drinkers than smokers (22.37 ± 7.60 vs. 15.55 ± 3.33%, p < 0.0001). Thus, cigarette smoking, and heavy alcohol intake can deteriorate sperm quality. However, alcohol consumption deteriorates sperm maturity and damages DNA integrity at significantly higher rates than cigarette smoking.

The Impact of Oxidative Stress in Male Infertility

At present infertility is affecting about 15% of couples and male factor is responsible for almost 50% of infertility cases. Oxidative stress, due to enhanced Reactive Oxygen Species (ROS) production and/or decreased antioxidants, has been repeatedly suggested as a new emerging causative factor of this condition. However, the central roles exerted by ROS in sperm physiology cannot be neglected. On these bases, the present review is focused on illustrating both the role of ROS in male infertility and their main sources of production. Oxidative stress assessment, the clinical use of redox biomarkers and the treatment of oxidative stress-related male infertility are also discussed.

The levels of oxidative DNA damage and some antioxidants in chronic osteomyelitis patients: A cross-sectional study

BACKGROUND

Osteomyelitis (OM) is a local or generalised infection of the bone and bone marrow which may be multifactorial in its causation. In this study, we aimed to determine oxidative DNA damage and antioxidant status of patients with chronic osteomyelitis.

MATERIAL METHOD

In this study, patients with chronic osteomyelitis and healthy controls were compared for descriptive characteristics (age and gender) and serum levels of malondialdehyde (MDA), 8-hydroxy-2-deoxy guanosine and antioxidant enzymes catalase, glutathione and superoxide dismutase.

RESULTS

This was a case-control study. About 5 mL of venous blood was collected for the estimation of biochemical parameters. This study comprised of 36 OM patients diagnosed, and 41 healthy ages (25-55 years) and sex-matched individuals. Antioxidant enzyme levels were significantly lower in patients with OM, whereas MDA and oxidative DNA damage levels were significantly higher.

CONCLUSION

The results obtained from this study have shown that the oxidant-antioxidant balance is impaired in patients with chronic osteomyelitis. It also supports that chronic osteomyelitis has associated with oxidative DNA damage.

Analysis of endogenous oxidative damage markers and association with pulmonary involvement severity in patients with SARS-CoV-2 pneumonia

Introduction

The SARS-CoV-2 virus affects many organs, especially the lungs, with widespread inflammation. We aimed to compare the endogenous oxidative damage markers of coenzyme Q10, nicotinamide dinucleotide oxidase 4, malondialdehyde, and ischemia-modified albumin levels in patients with pneumonia caused by SARS-CoV-2 and in an healthy control group. We also aimed to compare these parameters between patients with severe and non-severe pulmonary involvement.

Methods

The study included 58 adult patients with SARS-CoV-2 pneumonia and 30 healthy volunteers. CoQ10 and MDA levels were determined by high-pressure liquid chromatography. NOX4 and IMA levels were determined by ELISA assay and colorimetric method.

Results

Higher levels of CoQ10, MDA, NOX4, and IMA and lower levels of COQ10H were observed in patients with SARS-CoV-2 pneumonia than in the control group. MDA, IMA, NOX4, and CoQ10 levels were significantly higher in patients with severe pulmonary involvement than in patients with non-severe pulmonary involvement, but no significant difference was observed in CoQ10H levels. CoQ10 levels were significantly and positively correlated with both ferritin and CRP levels.

Conclusion

SARS-CoV-2 pneumonia is significantly associated with increased endogenous oxidative damage. Oxidative damage seems to be associated with pulmonary involvement severity.

The role of oxidative stress in association between disinfection by-products exposure and semen quality: A mediation analysis among men from an infertility clinic

Toxicological and epidemiologic evidence has suggested that exposure to disinfection by-products (DBPs) impairs semen quality, while the underlying biological mechanisms remain unclear. This study aimed to examine the mediating role of oxidative stress in association between DBP exposure and semen quality. We measured a urinary biomarker of DBP exposure [trichloroacetic acid (TCAA)] and three urinary biomarkers of oxidative stress [8-hydroxy-2-deoxyguanosine (8-OHdG), 8-iso-prostaglandin F2_α (8-isoPGF2_α) and 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA)] among men from an infertility clinic (n = 299). The associations of oxidative stress biomarkers with urinary TCAA and semen quality were evaluated using multivariable linear regression models, and the mediating role of oxidative stress biomarkers was assessed by a mediation analysis. Urinary TCAA was positively associated with urinary 8-OHdG and 8-isoPGF2_α in a dose-response manner (both P for trend < 0.001). Significantly inverse dose-response associations were observed between urinary 8-isoPGF2_α and sperm concentration and between urinary 8-OHdG and sperm motility (both P for trend < 0.05). The mediation analysis indicated a significant indirect effect of urinary 8-isoPGF2_α in the association between urinary TCAA and decreased sperm concentration (P = 0.01). Our results suggest that lipid peroxidation may be an intermediate mechanism by which DBP exposure impairs semen quality.

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 Antioxidant Biomarkers and Their Correlation with Clinical Condition and Lifestyle with Regard to Male Reproductive Potential

Measurement of sperm oxidative-antioxidant indicators is widely used in the assessment and detection of biochemical causes of male infertility The main purpose of this study was to identify biomarkers that assist in diagnostics and monitoring of male reproductive potential. We performed the assessment of oxidative-antioxidant malondialdehyde (MDA), glutathione (GSH), and total redox antioxidant potential (TRAP) indicators in seminal plasma, seminogram, clinical condition, and lifestyle of people with reproductive problems. The combined assessment of GSH and TRAP as potential biomarkers of male infertility in semen plasma was characterized by the highest total sensitivity and specificity. Furthermore, we provide evidence that male reproductive potential is significantly correlated with basic sperm parameters, sperm cell membrane integrity, their morphology, lifestyle, eating habits, occupation, and mental health. Our results provide evidence on the importance of oxidative stress and defense against free radicals in diagnosing and monitoring men with infertility that are consistent with previously conducted research. We provide an alternative approach on the possibility of interpreting the combination of the biomarkers that can bring benefits to a multi-threaded approach to the diagnosis and treatment of male infertility.

NOX4, MDA, IMA and oxidative DNA damage: can these parameters be used to estimate the presence and severity of OSA?

PURPOSE

Obstructive sleep apnoea (OSA) involves recurrent obstructive apnoeas and hypopnoeas which cause cyclic hypoxia, reoxygenation and formation of reactive oxygen species (ROS). We aimed to investigate a member of the nicotinamide adenine dinucleotide phosphate oxidase (NOX) family of enzymes, specifically (NOX4), not previously studied in humans, as well as 8-OHdG/106dG, MDA and IMA, which are known to be associated with oxidative stress. We also evaluated these parameters in predicting the presence and severity of OSA.

METHODS

All 120 subjects (90 with OSA, 30 healthy controls) underwent polysomnography and had blood serum samples taken at the same time of day. Subjects were grouped by presence and severity of OSA, and serum markers were compared among groups.

RESULTS

Age and body mass index were not significantly different among groups. In the OSA group, the levels of NOX4, IMA, MDA and 8-OHdG/106dG were significantly higher than in the healthy control group. NOX4 and other parameters were positively correlated with the severity of OSA. For all parameters, the highest levels were detected in patients with severe OSA.

CONCLUSIONS

The repeated hypoxia of OSA is associated with increases in the serum levels of inflammatory mediators such as MDA, IMA and 8-OHdG/106dG and the ROS NOX4. In this study, NOX4 and other markers were associated with the presence and severity of OSA.

Oxidative stress in the pathophysiology of male infertility

The effects of reactive oxygen species on male fertility are governed by the oxidative paradox, defined by a delicate balance between oxidative stress and antioxidant capacity. When regulated appropriately, reactive oxygen species ensure effective function; however, when uninhibited, they represent key players in male factor infertility. Mechanisms responsible for this include oxidative destruction of sperm lipid membranes, damage to gamete DNA both by gene mutation and by direct breakdown of the DNA backbone, mitochondrial dysfunction and apoptotic cell death. Utilizing various male pathologies as case studies, we see ways in which oxidative stress has the potential to impact fertility in a negative way. Varicocele, erectile dysfunction, testicular cancer and even idiopathic male infertility highlight common mechanistic pathways, as well as subtle variations in the ways reactive oxygen species can operate. Oxidative biomarkers have emerged to better study male infertility, predict reproductive success and modify assisted reproductive technologies to minimize oxidative stress.

Is male infertility associated with increased oxidative stress in seminal plasma? A-meta analysis

Objectives

We conducted a systematic review and meta-analysis of observational case-control studies to evaluate markers of oxidative stress in seminal plasma of patients with male infertility.

Background

Current evidence links oxidative stress to male infertility, in which multiple markers of oxidative stress have been widely detected, publishing inconsistent results with regard to the role of oxidative stress markers in the evaluation of male infertility. Therefore, a systematic review and meta-analysis on this issue is necessary.

Results

From the 1024 articles initially retrieved, 65 studies were included in our meta-analysis with 11 oxidative stress markers, containing 3819 male infertility patients and 2012 controls. The concentrations of malondialdehyde (SMD = 1.86, p < 0.00001), NO (SMD = 0.89, p = 0.001), carbonyl protein (SMD = 2.09, p < 0.00001) in seminal plasma were significantly higher in infertility patients. The concentrations of GSH (SMD = -1.68, p < 0.00001), vitamin C (SMD = -1.12, p < 0.00001), and vitamin E (SMD = -1.48, p = 0.003), as well as the activities of catalase (SMD = -1.91, p < 0.0001), glutathione peroxidase (SMD = -1.96, p = 0.0002) and glutathione-S-transferase (SMD = -1.62, p = 0.009) declined remarkably, resulting in decreased total antioxidant capacity (SMD = -1.77, p < 0.00001). Besides, the activity of superoxide dismutase showed no statistical difference between infertility patients and controls (SMD = -0.51, p = 0.07).

Conclusions

Our meta-analysis suggests that oxidative stress in seminal plasma resulting from decreased antioxidant defense are associated with male infertility.

Methods

Using PubMed, EMBASE, CNKI, VIP, and Wanfang database, we searched for literature reporting the detection of oxidative stress markers in the seminal plasma of male infertility published up to June 2017. Standardized mean differences (SMDs) and 95% confidence intervals (95%CI) were calculated for the finally analysis.

Non-Invasive Approaches to Epigenetic-Based Sperm Selection

Since sperm size and form do not necessarily provide information on internal sperm structures, novel sperm markers need to be found in order to conduct assisted reproductive therapies (ART) successfully. Currently, the priority of andrologists is not only to select those sperm able to fertilize the oocyte, but also a high quality of sperm that will guarantee a healthy embryo. Evidence of this shows us the importance of studying sperm intensively on genetic and epigenetic levels, because these could probably be the cause of a percentage of infertility diagnosed as idiopathic. Thus, more attention is being paid to posttranslational modifications as the key for better understanding of the fertilization process and its impact on embryo and offspring. Advances in the discovery of new sperm markers should go hand in hand with finding appropriate techniques for selecting the healthiest sperm, guaranteeing its non-invasiveness. To date, most sperm selection techniques can be harmful to sperm due to centrifugation or staining procedures. Some methods, such as microfluidic techniques, sperm nanopurifications, and Raman spectroscopy, have the potential to make selection gentle to sperm, tracking small abnormalities undetected by methods currently used. The fact that live cells could be analyzed without harmful effects creates the expectation of using them routinely in ART. In this review, we focus on the combination of sperm epigenetic status (modifications) as quality markers, with non-invasive sperm selection methods as novel approaches to improve ART outcomes.