8-HYDROXY-2′-DEOXYGUANOSINE IN LEUKOCYTE DNA OF SPERMATIC VEIN AS A BIOMARKER OF OXIDATIVE STRESS IN PATIENTS WITH VARICOCELE

Oxidative Stress and Male Infertility: Evidence From a Research Perspective

Male fertility potential can be influenced by a variety of conditions that frequently coincide. Spermatozoa are particularly susceptible to oxidative damage due to their limited antioxidant capacity and cell membrane rich in polyunsaturated fatty acids (PUFAs). The role of oxidative stress (OS) in the etiology of male infertility has been the primary focus of our Stellenbosch University Reproductive Research Group (SURRG) over the last 10 years. This review aims to provide a novel insight into the impact of OS on spermatozoa and male reproductive function by reviewing the OS-related findings from a wide variety of studies conducted in our laboratory, along with those emerging from other investigators. We will provide a concise overview of the production of reactive oxygen species (ROS) and the development of OS in the male reproductive tract along with the physiological and pathological effects thereof on male reproductive functions. Recent advances in methods and techniques used for the assessment of OS will also be highlighted. We will furthermore consider the current evidence regarding the association between OS and ejaculatory abstinence period, as well as the potential mechanisms involved in the pathophysiology of various systemic diseases such as obesity, insulin resistance, hypertension, and certain mental health disorders which have been shown to cause OS induced male infertility. Finally, special emphasis will be placed on the potential for transferring and incorporating research findings emanating from different experimental studies into clinical practice.

Comparison of outcomes in intrauterine insemination, in vitro fertilisation and intracytoplasmic sperm injection in men with and without varicocele

Objectives: To investigate the differences in clinical pregnancy, miscarriage, and live birth rates when male partners were diagnosed with a varicocele and to compare these outcomes to those without and study the outcomes based on the grade of varicocele. Methods: The retrospective study was based on a cohort of consecutive infertile couples undergoing assisted reproductive technology (ART) at the Reproductive Center of Shandong Provincial Hospital affiliated to the Shandong University during the period between January 2017 and December 2018. A total of 4203 couples comprised of men with and without varicocele undergoing the first ART cycle (1501 intrauterine inseminations (IUI), 1623 in vitro fertilisations (IVF) and 1079 intracytoplasmic sperm injections (ICSI)) were included. Semen parameters and ART outcomes were determined. Results: ICSI (26.5%) originated from men with a significant lower level in sperm concentration and motility but with a strict normal morphology had a higher prevalence of varicocele than men undergoing IUI (20.7%) and IVF (18.1%). In IUI, the odds ratios (ORs) for pregnancy and live birth were significantly lower for couples in men diagnosed with grades 1 or 2 varicocele as compared to those for men with grade 3 varicocele. In IVF, ORs for live birth where men were diagnosed with grades 1 or 2 varicocele were also lower than those for men with grade 3,whereas a higher miscarriage rate was found when men had grades 1 or 2 varicocele than when men had grade 3. However, for ICSI, no significant outcomes were found in grades 1, 2 or 3 varicocele versus the no varicocele group. Conclusions: The increasing grade of varicocele was negatively associated with sperm parameters and can alter the outcome of further IUI/IVF.

Mediation of the relationship between phthalate exposure and semen quality by oxidative stress among 1034 reproductive-aged Chinese men

BACKGROUND

Emerging evidence from animals indicates that oxidative stress plays a crucial role in the effects of phthalate exposure on male reproductive dysfunctions, which has never been thoroughly explored in humans.

OBJECTIVE

To explore the potential mediating role of oxidative stress in the association of phthalate exposure with semen quality among 1034 Chinese men.

METHOD

Repeated urine samples gathered from the male partners of sub-fertile couples were analyzed for 3 oxidative stress markers [8-hydroxy-2-deoxyguanosine (8-OHdG), 8-iso-prostaglandin F_2α (8-isoPGF_2α) and 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA)], using a liquid chromatography-tandem mass spectrometry. Multivariate regression models were constructed to evaluate the associations of urinary oxidative stress markers with urinary phthalate metabolites and semen quality. We also explored the potential mediation effects by oxidative stress markers.

RESULTS

Significantly positive dose-dependent relationships were observed between each individual phthalate metabolite and all analyzed oxidative stress markers (all p for trend<0.05), except for monoethyl phthalate (MEP) in relation to HNE-MA. Additionally, significantly or suggestively inverse dose-dependent relationships were exhibited between urinary 8-isoPGF_2α and sperm concentration (p for trend = 0.05), and between urinary 8-OHdG and percent of normal sperm morphology (p for trend = 0.01). Mediation analysis showed that urinary 8-isoPGF_2α suggestively mediated 12% of the inverse association between monobutyl phthalate (MBP) and sperm concentration, and that urinary 8-OHdG suggestively mediated 32% of the inverse association of MEP with percent of normal sperm morphology (both p < 0.10).

CONCLUSIONS

Although further investigations are required, our results suggest that oxidative stress may play a mediating role in the effects of phthalate exposure on impaired semen quality.

Melatonin and its metabolites vs oxidative stress: From individual actions to collective protection

Oxidative stress (OS) represents a threat to the chemical integrity of biomolecules including lipids, proteins, and DNA. The associated molecular damage frequently results in serious health issues, which justifies our concern about this phenomenon. In addition to enzymatic defense mechanisms, there are compounds (usually referred to as antioxidants) that offer chemical protection against oxidative events. Among them, melatonin and its metabolites constitute a particularly efficient chemical family. They offer protection against OS as individual chemical entities through a wide variety of mechanisms including electron transfer, hydrogen transfer, radical adduct formation, and metal chelation, and by repairing biological targets. In fact, many of them including melatonin can be classified as multipurpose antioxidants. However, what seems to be unique to the melatonin's family is their collective effects. Because the members of this family are metabolically related, most of them are expected to be present in living organisms wherever melatonin is produced. Therefore, the protection exerted by melatonin against OS may be viewed as a result of the combined antioxidant effects of the parent molecule and its metabolites. Melatonin's family is rather exceptional in this regard, offering versatile and collective antioxidant protection against OS. It certainly seems that melatonin is one of the best nature's defenses against oxidative damage.

Relevance of peroxynitrite formation and 3-nitrotyrosine on spermatozoa physiology

HIGHLIGHTS

Male fertility decline has been attributed, in part, to increased oxidative stress.Here we will focus on spermatozoa ROS, namely O2•-, NO and ONOO- and their contribution to protein tyrosine nitration, namely by 3-NT formation.An in depth review will be made on the methods used to detect protein oxidation.Detecting 3-NT in sperm proteins will have a crucial clinical impact, namely on the follow up of anti-oxidant therapies.

ABSTRACT

Infertility is a clinical condition that affects around 15% of reproductive-aged couples worldwide. Around half of these cases are due to male factors, the most owing to idiopathic causes. The increase of reactive oxygen species (ROS), which leads to oxidative stress (OS), has been discussed in the last years as a possible cause of male idiopathic infertility. Superoxide anion (O2 •-) and nitric oxide (NO) can react with each other contributing to the formation of peroxynitrite (ONOO-). This molecule can then act on spermatozoa proteins, leading to nitration of protein tyrosines - addition of a nitro (NO2) group - that is then manifested by the formation of 3-nitrotyrosine (3-NT). In turn, 3-NT may be responsible for the alteration or inactivation of the protein function.This review will focus on the description of spermatozoa ROS, namely O2 •-, NO and ONOO- and in their contribution to protein tyrosine nitration, namely by 3-NT formation. Previous results about the effect of ONOO- and 3-NT in spermatozoa will be presented, as well as, the methods that can be performed to detect the protein oxidation by these species. The impact of measuring, at the clinical level, 3-NT, considered a marker of OS, in spermatozoa will be discussed.

Sperm nuclear vacuoles in relation to acrosome reactions and sperm motility

We investigated sperm nuclear vacuolation in relation to acrosome reactions and the maintenance of sperm motility. Thirty male patients who visited our Male Infertility Clinic were enrolled. These patients underwent conventional semen analyses, Acrobeads tests, and high-magnification observation of the sperm head to evaluate the degree of nuclear vacuolation on the Acrobeads test scoring after 24 hours of incubation. The presence of acrosome reactions was evaluated using the Acrobeads test. The spermatozoa were classified into three groups: (I) those bound to MH61-beads, (II) motile spermatozoa that did not bind to MH61-beads, and (III) immotile spermatozoa that did not bind to MH61-beads. The percentage of spermatozoa with large nuclear vacuoles (%LNV) was compared between the three groups. The degree of sperm nuclear vacuolation was evaluated in 17,992 ejaculated spermatozoa. The mean %LNVs were 2.4% in group I, 5.8% in group II, and 9.8% in group III. These values were significantly different from each other (P < 0.001, paired t-test). There were no correlations between the %LNV values and the Acrobeads scores. In conclusion, the degree of sperm nuclear vacuolation was significantly lower in the acrosome-reacted spermatozoa and spermatozoa with maintained motility, and higher in the immotile spermatozoa that did not bind to MH61-beads.

Observation of spermatozoa by a high-magnification microscope

Semen analyses are the primary tool for evaluating male infertility, as semen parameters are useful for predicting potential fertility. In the field of assisted reproductive technology (ART), the single best motile spermatozoon should be selected, especially when performing intracytoplasmic sperm injection (ICSI). In this context, the motile sperm organelle morphology examination (MSOME) was developed as a method of assessing the detailed morphology of motile spermatozoa in real time at a magnification of up to 6,300× on a video system. The use of ICSI with MSOME-selected sperm is called intracytoplasmic morphologically selected sperm injection (IMSI). IMSI improves the outcomes of ICSI. MSOME can be also applied to evaluate male infertility. Among MSOME parameters, the presence of sperm nuclear vacuoles is the most important finding. Large sperm nuclear vacuoles (LNV) are related not only to poor ART outcomes, but also to poor semen quality and sperm DNA damage, such as DNA fragmentation and chromatin condensation failure. It has been suggested that sperm head vacuoles are produced at earlier stages of sperm maturation. It is possible that the number of LNV can be decreased by surgical or medical treatment for male infertility. Therefore, the level of LNV has the potential to be used as an alternative parameter of semen quality and a new tool for evaluating the therapeutic effects of treatment in male patients with infertility.

Sperm chromatin structure assay (SCSA®)

The SCSA(®) is the pioneering assay for the detection of damaged sperm DNA and altered proteins in sperm nuclei via flow cytometry of acridine orange (AO) stained sperm. The SCSA(®) is considered to be the most precise and repeatable test providing very unique, dual parameter data (red vs. green fluorescence) on a 1,024 × 1,024 channel scale, not only on DNA fragmentation but also on abnormal sperm characterized by lack of normal exchange of histones to protamines. Raw semen/sperm aliquots or purified sperm can be flash frozen, placed in a box with dry ice and shipped by overnight courier to an experienced SCSA(®) lab. The samples are individually thawed, prepared, and analyzed in ∼10 min. Of significance, data on 5,000 individual sperm are recorded on a 1,024 × 1,024 dot plot of green (native DNA) and red (broken DNA) fluorescence. Repeat measurements have virtually identical dot plot patterns demonstrating that the low pH treatment that opens up the DNA strands at the sites of breaks and staining by acridine orange (AO) are highly precise and repeatable (CVs of 1-3%) and the same between fresh and frozen samples. SCSAsoft(®) software transforms the X-Y data to total DNA stainability versus red/red + green fluoresence (DFI) providing a more accurate determination of % DFI as well as the more sensitive value of standard deviation of DFI (SD DFI) as demonstrated by animal fertility and dose-response toxicology studies. The current established clinical threshold is 25% DFI for placing a man into a statistical probability of the following: (a) longer time to natural pregnancy, (b) low odds of IUI pregnancy, (c) more miscarriages, or (d) no pregnancy. Changes in lifestyle as well as medical intervention can lower the %DFI to increase the probability of natural pregnancy. Couples of men with >25% DFI are counseled to try ICSI and when in the >50% range may consider TESE/ICSI. The SCSA(®) simultaneously determines the % of sperm with high DNA stainability (%HDS) related to retained nuclear histones consistent with immature sperm; high HDS values are predictive of pregnancy failure.The SCSA(®) is considered to be the most technician friendly, time- and cost-efficient, precise and repeatable DNA fragmentation assay, with the most data and the only fragmentation assay with an accepted clinical threshold for placing a man at risk for infertility. SCSA(®) data are more predictive of male factor infertility than classical semen analyses.

Ultrastructure of the seminiferous tubules in oligoasthenoteratozoospermic men associated with varicocele

Varicocele is associated with venous reflux that may cause increased heat and interstitial pressure within the testes, with variable pathological effects on spermatogenesis. This study aimed to study the ultrastructural testicular changes in the seminiferous tubules of 20 infertile severe oligoasthenoteratozoospermia (OAT) men associated with varicocele and five patients with obstructive azoospermia without varicocele as controls. They were subjected to testicular biopsy which was evaluated by transmission electron microscopy. Ultrastructurally, the seminiferous epithelium in the testicular biopsies of infertile severe OAT men associated with varicocele was variably affected in the form of thickening of the peritubular connective tissue, vacuolation of Sertoli cell and germ cell cytoplasm, presence of degenerated and apoptotic cells among the germinal epithelium, altered spermatids and abnormal spermatozoa. It is concluded that varicocele in severe OAT men is associated with ultrastructural changes in the seminiferous tubule.

Relationship between varicocele and sperm DNA damage and the effect of varicocele repair: a meta-analysis

Varicocele, a cause of male infertility, occurs in nearly 40% of infertile males. It has been postulated that varicoceles may cause sperm DNA damage. Sperm DNA integrity has been recognized as one of the important determinants of normal fertilization and embryo growth in natural and assisted conception. Eighty-three human studies were identified after an extensive literature search involving the role of varicoceles in sperm DNA damage. Of the 83 studies, 12 were selected that measured similar types of reactive sperm DNA damage. Seven studies determined the damage of sperm DNA in varicocele-associated patients and six studies evaluated the efficacy of varicocelectomy. One study was a duplicate because both outcomes were included. Data were analysed using RevMan software. The overall estimate showed that patients with varicoceles have significantly higher sperm DNA damage than controls, with a mean difference of 9.84% (95% CI 9.19 to 10.49; P<0.00001). A varicocelectomy can improve sperm DNA integrity, with a mean difference of -3.37% (95% CI -4.09 to -2.65; P<0.00001). In conclusion, there is increased sperm DNA damage in patients with varicoceles and varicocelectomy may be a possible treatment; however, more studies with appropriate controls are needed to confirm this finding. A varicocele is an important cause of male infertility and occurs in nearly 40% of infertile males. The recent understanding of the effect of varicoceles in male reproduction has led some researchers to postulate varicoceles as the possible cause of sperm DNA damage. Eighty-three human studies were identified after an extensive literature search involving the role of varicoceles in sperm DNA damage. Of the 83 studies, 12 were selected that measured similar types of reactive sperm DNA damage by a similar method. Seven studies determined the damage of sperm DNA in varicocele-associated patients and six studies evaluated the efficacy of varicocelectomy. One study was a duplicate because both outcomes were included. The data were then entered in the RevMan software for analysis. The overall estimate showed that patients with varicoceles have significantly higher sperm DNA damage than controls, with a mean difference of 9.84% (95% CI 9.19 to 10.49; P<0.00001). A varicocelectomy can improve sperm DNA integrity, with a mean difference of -3.37% (95% CI -4.09 to -2.65; P<0.00001). Based on the results, it can be concluded that there is increased sperm DNA damage in patients with varicoceles and that varicocelectomy may be a possible treatment; however, more studies with appropriate controls are needed to confirm this finding.

Are varicoceles associated with increased deoxyribonucleic acid fragmentation?

OBJECTIVE

To perform a literature search on the association between varicocele and sperm DNA fragmentation.

DESIGN

Systematic review.

PATIENT(S)

Men with a varicocele and infertility.

INTERVENTION(S)

Varicocele repair.

MAIN OUTCOME MEASURE(S)

Does the presence of a varicocele increase seminal oxidative stress and sperm DNA fragmentation?

RESULT(S)

In men with a varicocele increased levels of reactive oxygen species and sperm DNA damage can be found. This is probably related to defective spermatogenesis in these patients. Seminal oxidative stress is believed to be the source of sperm DNA damage. Patients with a varicocele and oligospermia may also have a diminished seminal antioxidant capacity. After varicocele repair sperm DNA fragmentation decreases.

CONCLUSION(S)

Varicocele is associated with sperm DNA damage, and this sperm pathology may be secondary to varicocele-mediated oxidative stress. The beneficial effect of varicocelectomy on sperm DNA damage further supports the premise that varicocele may impair sperm DNA integrity.

Differences in biochemical markers and body mass index between patients with and without varicocele

BACKGROUND

Varicocele is characterized by abnormal tortuosity and dilatation of the veins of the pampiniform plexus within the spermatic cord and is one of the causes of male infertility. This study aimed to evaluate the differences in biochemical markers and body mass index (BMI) between patients with and without varicocele.

METHODS

Between January 2004 and June 2009, 102 patients with varicocele (Group A) were evaluated. Ninety-five age-matched male patients who did not have varicocele were selected as controls (Group B). Varicocele was diagnosed by physical examination and confirmed by Doppler ultrasonography. The range of ages was between 18 and 50 years old. BMI, testosterone, serum alkaline phosphatase, calcium, lactic dehydrogenase, inorganic phosphate, gammaglutamine transpeptidase, uric acid, albumin, iron, cholesterol, triglyceride, alanine aminotransferase, and aspartate aminotrans-ferase levels were measured for all the subjects.

RESULTS

The mean age was 35.4 years in group A and 36.5 years in group B. Of the 102 patients in group A, 20 were grade 1 varicocele, 55 were grade 2 and 27 were grade 3. The BMI (mean +/- SD) of patients with varicocele (22.8 +/- 3.2) was significantly lower than that of patients without varicocele (24.9 +/- 4.1). Patients with varicocele had significantly lower serum levels of cholesterol than patients without varicocele (176.5 +/- 31.1 vs. 187.7 +/- 42.1 mg/dL). There were no significant differences for the other biochemical markers between the groups. Patients with grade 3 varicocele had a lower BMI than patients with grades 1 and 2 varicocele, but this was not significant. No significant differences were found for the other biochemical markers among the patients with grade 1, 2 or 3 varicocele.

CONCLUSION

Patients with varicocele had significantly lower serum levels of cholesterol than those without varicocele. In addition, the prevalence of varicocele was higher in patients with a lower BMI. Our findings suggest that patients with a greater BMI may have advantages in relieving the nutcracker phenomenon, which causes significant varicoceles.

Butin decreases oxidative stress-induced 8-hydroxy-2'-deoxyguanosine levels via activation of oxoguanine glycosylase 1

In response to oxidative DNA base damage, oxoguanine glycosylase 1 (OGG1), in a base-excision repair (BER) pathway in mammals, plays a vital role in the repair of 8-hydroxy-2'-deoxyguanosine (8-OHdG), which is a reliable marker of reactive oxygen species (ROS)-induced DNA base modification and contributes to the pathologic process of cancer. Recently, we have shown that butin (7,3',4'-trihydroxydihydroflavone) protects cells against hydrogen peroxide (H2O2)-induced damage of cellular components including DNA. In the present study, we examined the possible protective effect of butin on oxidative stress-induced DNA base modification, especially 8-OHdG. Hydrogen peroxide significantly increased the level of 8-OHdG, which was detected by 8-OHdG ELISA and confocal microscopy, but butin decreased this level. Suppression of 8-OHdG formation by butin was related to the enhanced mRNA and protein expression of OGG1, which was detected by RT-PCR and Western blot analysis. Butin also increased the transcriptional activity of OGG1, which was suppressed by H2O2 treatment; this transcriptional activity was detected by OGG1 promoter luciferase assay. Butin enhanced the expression of phosphorylated Akt (active form of Akt), a regulator of OGG1, which was decreased by H2O2 treatment. A PI3K-specific inhibitor, LY294002, abolished the phosphorylated Akt and OGG1 expressions induced by butin, suggesting that OGG1 induction by butin involves the PI3K/Akt pathway.

Negative effects of serum p,p'-DDE on sperm parameters and modification by genetic polymorphisms

OBJECTIVE

Effects of ambient exposure to DDT and its metabolites (DDE-DDT) on human sperm parameters and the role of genetic polymorphisms in modifying the association were investigated.

METHODS

Demographics, medical history data, blood and semen samples were obtained from the first 336 male partners of couples presenting to 2 infertility clinics. Serum was analyzed for organochlorines (OC) and DNA for polymorphisms in GSTM1, GSTT1, GSTP1 and CYP1A1. Men with each sperm parameter considered low by WHO criteria (concentration <20million/mL, motility <50%, morphology <4%) were compared to men with all normal sperm parameters in logistic regression models, controlling for sum of other OC pesticides.

RESULTS

High DDE-DDT level was associated with significantly increased odds for all 3 low sperm parameters. The risk of low motility with high DDE-DDT exposure was increased in men with the GSTT1 null genotype compared to those with GSTT1 intact (odds ratio (OR)=4.19, 95% confidence interval (CI) 1.05-16.78 and OR=3.57, 1.43-8.93, respectively). Risk for low morphology in men with high DDE-DDT and one or both CYP1A1*2A alleles was lower compared to men with the common CYP1A1 alleles (OR=2.18, 0.78-6.07 vs. OR=3.45, 1.32-9.03, respectively). Similar results were obtained for men with low DDE-DDT exposure. Effects of high DDE-DDT on low sperm concentration (OR=2.53, 1.0-6.31) was unaffected by the presence of the polymorphisms.

CONCLUSION

High DDE-DDT exposure adversely affected all 3 sperm parameters and its effects were exacerbated by the GSTT1 null polymorphism and by the CYP1A1 common alleles.

Role of oxidative stress in pathogenesis of varicocele and infertility

This review summarizes the published literature about the role of oxidative stress in the pathophysiology of varicocele and the beneficial effects of varicocele repair on oxidative stress. Literature survey was performed using the Medline, EMBASE, BIOSIS, and Cochrane databases between 1993 and 2008 that were relevant to oxidative stress and varicocele. Varicocele treatment can reduce reactive oxygen species levels and improve sperm parameters and pregnancy rates, although it is still controversial with Assisted Reproductive Techniques outcomes. We conclude that spermatozoal dysfunction in varicocele patients could be multifactorial, and oxidative stress-induced injury appears to be one of the main causes.

5'-Nucleotidase activity is decreased in seminal plasma and spermatozoa from varicocele patients

5'-Nucleotidase is involved in sperm capacitation via the cAMP-adenosine pathway and in sperm motility via direct adenosine production from AMP. Since these functions are reduced in varicocele, the aim of this study was to investigate whether the enzyme levels were altered in sperm from varicocele patients. The mean (SD) international units (IU) of 5'-nucleotidase activity in seminal plasma from 35 varicocele III patients was 0.16(0.09) IU ml(-1) vs 0.35(0.13) IU ml(-1) in 53 controls, this decrease being statistically significant at p < or = 0.001. A significant decrease in activity, expressed as international units per mg of protein concentration in spermatozoa homogenates, was also observed with spermatozoa: 0.0018(0.0017) IU mg(-1) in varicocele III vs 0.0081(0.0060) IU mg(-1) in controls, at p < or = 0.001. Compared to controls, the activity decrease observed both in spermatozoa and seminal plasma from 45 men with varicocele I was not statistically significant at p < or = 0.05. To determine the diagnostic value of 5'-nucleotidase in assessing sperm fertility in varicocele III, we used the likelihood ratios method and best cut-offs were identified in receiver operating characteristic curves. With a prevalence of 36%, the post-test probability of infertility was 91% in spermatozoa and 78% in seminal plasma. The cut-off values of 5'-nucleotidase activity discriminating for fertile/unfertile semen were 0.2 IU ml(-1) in seminal plasma and 0.003 IU mg(-1) of protein in spermatozoa. Overall, determination of 5'-nucleotidase activity, especially in spermatozoa, can be useful to characterize different varicocele degrees as well as the sperm fertility potential.

The role of varicocele repair in the new era of assisted reproductive technology

Infertility affects 10-15% of couples who are trying to conceive, and half of the cases are due to male infertility. Intracytoplasmic sperm injection is increasingly being used to overcome multiple sperm deficiencies. Due to its effectiveness, some have proposed ICSI as a solution for all cases of male infertility, regardless of the cause. Hence, even men with potentially treatable causes of infertility have sought the aid of assisted reproductive technology, rather than undergo specific therapies to treat their infertility. Varicoceles are the most frequent physical finding in infertile men; indeed, they may be responsible for nearly one-third of cases of male infertility. Varicocele management, however, has always been a controversial issue because very few randomized, controlled studies have been performed to examine varicocelectomy as an infertility treatment. Significant evidence suggests that varicoceles have a harmful effect on the testis and that varicocelectomy can not only prevent progressive decline in testicular function but also reverse the damage. However, the degree to which varicocele repair improves pregnancy rates and the success of assisted reproductive technology remains controversial.

Increase of oxidative stress in human sperm with lower motility

OBJECTIVE

To investigate the causal role of oxidative-stress status on human sperm motility.

DESIGN

To demonstrate that sperm with higher oxidative damage have a lower antioxidant capacity.

SETTING

University hospital infertility center.

PATIENT(S)

Seventy-eight semen samples were obtained from 35 healthy donors who had normal semen characteristics and from 43 infertile or subfertile males.

INTERVENTION(S)

The levels of oxidative damage (8-hydroxy-2'-deoxyguanosine [8-OHdG] and lipid peroxides) and antioxidants (retinol, alpha-tocopherol, ascorbate, and protein thiols) in the spermatozoa and/or seminal plasma were measured.

MAIN OUTCOME MEASURE(S)

We analyzed the specific content of 8-OHdG and lipid peroxides by using high-performance liquid chromatography (HPLC)-electrochemical detection and HPLC-fluorescence analysis, respectively. Retinol and alpha-tocopherol were analyzed by using an HPLC system, whereas ascorbate and protein thiols were determined by using spectrophotometry. 8-Hydroxy-2'-deoxyguanosine was visualized by immunofluorescent staining with an anti-8-OHdG antibody that was conjugated with fluorescein isothiocyanate conjugate. Lipid peroxides in spermatozoa were stained with a fluorescent dye, C11-BODIPY(581/591).

RESULT(S)

Statistically significant negative correlations were revealed between sperm motility and 8-OHdG and between motility and lipid peroxides. Statistically significant positive correlations were found between sperm motility and the levels of retinol, alpha-tocopherol, ascorbate, and protein thiols of seminal plasma. 8-Hydroxy-2'-deoxyguanosine and lipid peroxides in spermatozoa were found to be present mostly in mitochondria.

CONCLUSION(S)

Oxidative stress and oxidative damage were increased significantly in spermatozoa with declined motility, and the antioxidant capacities in the spermatozoa and seminal plasma were lower in males who had infertility or subfertility.

Oxidative stress and male infertility--a clinical perspective

Oxidative stress occurs when the production of potentially destructive reactive oxygen species (ROS) exceeds the bodies own natural antioxidant defenses, resulting in cellular damage. Oxidative stress is a common pathology seen in approximately half of all infertile men. ROS, defined as including oxygen ions, free radicals and peroxides are generated by sperm and seminal leukocytes within semen and produce infertility by two key mechanisms. First, they damage the sperm membrane, decreasing sperm motility and its ability to fuse with the oocyte. Second, ROS can alter the sperm DNA, resulting in the passage of defective paternal DNA on to the conceptus. This review will provide an overview of oxidative biochemistry related to sperm health and will identify which men are most at risk of oxidative infertility. Finally, the review will outline methods available for diagnosing oxidative stress and the various treatments available.

Subclinical varicocele in the pediatric age group

PURPOSE

This study was designed to assess the natural history of subclinical varicocele in the pediatric age group.

MATERIALS AND METHODS

We conducted a school screening for varicocele in 2,107 children 10 to 16 years old, performing clinical examination and venous Doppler study. A total of 354 boys (16.8%) without clinically detectable varicocele had venous testicular reflux during a Valsalva maneuver. Of these children 36 (a 10% sample) were selected randomly and followed annually for 4 years, with assessment of testicular volume (ultrasound values), degree of varicocele according to the Dubin and Amelar classification, and Doppler findings according to the Hirsh testicular Doppler classification. The control group consisted of 20 children selected randomly from the same population, who did not have a varicocele and had a normal Doppler study. Fisher's exact test was used with a significance value at p <0.05.

RESULTS

Mean age of the 36 children at the first assessment was 12.8 years (SD 1.7). Two boys (5.5%) had spontaneous resolution of testicular venous reflux within 2 years, and in 24 (67%) the subclinical varicocele did not change. The remaining 10 children (28%) had a clinically detectable varicocele, which was grade I in 1 patient, grade II in 7 and grade III in 2. Of these patients 1 had associated left testicular hypoplasia greater than 20%. During the 4-year period there were no clinically detectable varicoceles in the control group (p = 0.01).

CONCLUSIONS

The proportion of children with subclinical varicocele progressing to a clinically detectable form of the condition was 28% (95% CI 14 to 45) during a 4-year period. We suggest that children with subclinical varicocele require long-term followup.

DNA damage and chromosomal aberrations in various types of male factor infertility

OBJECTIVE

To understand and delineate the nature and level of DNA damage in association to semen parameters in infertile men.

DESIGN

A prospective experimental study.

SETTING

Alexandroupolis University General Hospital.

PATIENT(S)

Eleven fertile and 27 infertile men with various types of infertility.

INTERVENTION(S)

DNA damage was induced by addition of mitomycin C and caffeine to lymphocyte cultures.

MAIN OUTCOME MEASURE(S)

Sister chromatid exchange (SCE) levels were assessed in cultures providing a quantitative index of genotoxicity and chromosomal analysis was performed using G-banding and C-banding techniques.

RESULT(S)

Karyotyping analysis indicated chromosomal fragility, trisomic lines, and marker chromosomes in some infertile men. Double minute chromosomes were noticed in 11 infertile men and were positively correlated with elevated SCE levels. Necrospermia and varicocele, irrespectively of the degree of severity, were positively correlated with elevated SCE levels.

CONCLUSION(S)

Infertile men are prone to have DNA damage; the nature and level of DNA damage varies and is associated with semen parameters. The presence of double minute chromosomes alone is associated with increased double-stranded breaks and abnormal sperm concentration. This study could provide the basis to establish whether and through which process double minute chromosomes could be related to poor semen parameters and regulation of DNA repair.

Attenuation of oxidative stress after varicocelectomy in subfertile patients with varicocele

PURPOSE

We examined changes due to oxidative damage to spermatozoa and alterations in antioxidant capacity in subfertile patients with varicocele before and after varicocelectomy in a prospective study.

MATERIALS AND METHODS

A total of 30 young subfertile male patients with varicocele were recruited in this study. Varicocele was diagnosed by physical examination and Doppler ultrasound. Semen analysis was performed in the 30 patients before and 6 months after varicocelectomy using a computer assisted semen analyzer. The parameters for evaluating oxidative stress changes were 4977 bp deletion of mitochondrial DNA in sperm, as detected by polymerase chain reaction, the 8-OHdG (8-hydroxy-2'-deoxyguanosine) content in spermatozoa DNA, as measured by a high performance liquid chromatography electrochemical method, and seminal plasma protein thiols and ascorbic acid, as measured by spectrophotometric methods.

RESULTS

Semen quality, including motility, morphology and sperm density, was improved in 22 patients (73.3%) after varicocelectomy. The incidence of 4977 bp deletion of mitochondrial DNA in sperm was 40% (12 of 30 patients) and 13.3% (4 of 30) before and after surgery, respectively. Mean +/- SD 8-OHdG content in sperm DNA, and seminal plasma protein thiols and ascorbic acid were 10.27 +/- 2.24/10(5) 2'-deoxyguanosine, 0.77 +/- 0.75 nmole/ml and 1.87 +/- 0.40 mg/dl before operation, and 5.95 +/- 1.46/10(5) 2'-deoxyguanosine, 3.00 +/- 1.17 nmole/ml and 3.12 +/- 0.94 mg/dl after surgery, respectively. The incidence of 4977 bp deletion of mitochondrial DNA in sperm and the level of 8-OHdG in sperm DNA were decreased, and seminal plasma protein thiols and ascorbic acid were increased significantly in all 30 patients after varicocelectomy. Also, in the 8 patients in whom semen quality did not improve after surgery a significant decrease in 8-OHdG in sperm DNA, and a significant increase in seminal plasma protein thiols and ascorbic acid were observed.

CONCLUSIONS

Subfertile patients with varicocele had a significant decrease in oxidative damage in sperm DNA and an increase in antioxidant capacity in seminal plasma after varicocelectomy, indicating that surgery is effective treatment in such patients.

Significant decrease in sperm deoxyribonucleic acid fragmentation after varicocelectomy

OBJECTIVE

To measure sperm DNA integrity values before and after varicocelectomy in patients with elevated preoperative levels of sperm DNA fragmentation.

DESIGN

Retrospective.

SETTING

Private urology clinic.

PATIENT(S)

Eleven patients with grade 1, 2, or 3 varicocele.

INTERVENTION(S)

Varicocelectomy.

MAIN OUTCOME MEASURE(S)

Sperm DNA fragmentation values were assessed before and after varicocelectomy.

RESULTS(S)

Ninety percent of the patients showed a significant decrease in sperm DNA fragmentation levels.

CONCLUSIONS(S)

Although this study was small, 10 of the 11 patients with varicocele showed a significant decrease in sperm DNA fragmentation after varicocele repair. Elevated sperm DNA fragmentation has been shown to have a significant negative effect on pregnancy outcome with use of in vivo, IUI, routine IVF, and to a lesser extent intracytoplasmic sperm injection fertilization; therefore pregnancy outcome may improve after varicocelectomy.