Association of sperm apoptosis and DNA ploidy with sperm chromatin quality in human spermatozoa

The Use of Non-Apoptotic Sperm Selected by Magnetic Activated Cell Sorting (MACS) to Enhance Reproductive Outcomes: What the Evidence Says

Sperm selection of the most competent sperm is a promising way to enhance reproductive outcomes. Apoptosis is the programmed cell death process to maintain tissue homeostasis, and MACS sperm selection of non-apoptotic cells enables the removal of apoptotic sperm from an ejaculate, thus leaving the non-apoptotic available to be microinjected, but given the associated costs of adding these sperm selection steps to the routine practice, there is a need for a careful examination of the literature available to answer questions such as who can benefit from this MACS, how significant this improvement is, and how robust the evidence and data available supporting this choice are. Thus, the aim of this narrative review was to objectively evaluate the available evidence regarding the potential benefits of the use of MACS. From the literature, there are controversial results since its implementation as an in vitro fertilization add-on, and this may be explained in part by the low quality of the evidence available, wrong designs, or even inadequate statistical analyses. We concluded that the benefits of adding MACS are unclear, and further methodologically sound research on specific populations is much needed before offering it clinically.

Analyzing the Differential Impact of Semen Preparation Methods on the Outcomes of Assisted Reproductive Techniques

Sperm separation plays a critical role in assisted reproductive technology. Based on migration, density gradient centrifugation and filtration, a properly selected sperm could help in increasing assisted reproductive outcomes in teratozoospermia (TZs). The current study aimed to assess the prognostic value of four sperm selection techniques: density gradient centrifugation (DGC), swim-up (SU), DGC-SU and DGC followed by magnetic-activated cell sorting (DGC-MACS). These were evaluated using spermatozoa functional parameters. A total of 385 infertile couples underwent the procedure of intracytoplasmic sperm injection (ICSI), with an isolated teratozoospermia in the male partner. Semen samples were prepared by using one of the mentioned sperm preparation techniques. The improvements in the percentage of normal mature spermatozoa, rate of fertilization, cleavage, pregnancy and the number of live births were assessed. The normal morphology, spermatozoa DNA fragmentation (SDF) and chromatin maturity checked by using chromomycin A3 (CMA3) with DGC-MACS preparation were better compared to the other three methods. Embryo cleavage, clinical pregnancy and implantation were better improved in the DGC-MACS than in the other tested techniques. The DGC-MACS technique helped in the selection of an increased percentage of normal viable and mature sperm with intact chromatin integrity in patients with teratozoospermia.

Testicle histology of the Epicrates cenchria: a morphological and reproductive biology analysis

ABSTRACT The lack of information about anatomy, physiology and reproductive biology in many snake species makes the understanding of these free-living animals’ reproduction and reproductive biotechnics application in captivity difficult. The present study aims to evaluate the Epicrates cenchria’s testicle morphology and correlate these findings with environmental aspects and reproductive biology. The testicles of five specimens of E. cenchria were histologically evaluated, and it was possible to observe seasonality in sperm production, with the presence of mature spermatozoa in the wettest and warmest periods of the year, as well as the highest testicular volume in these periods. Correlating these findings with that reported in the literature on copulation period presupposes a prenuptial (or associated) pattern in E. cenchria.

Cumulative live birth rates in donor oocyte ICSI cycles are not improved by magnetic-activated cell sorting sperm selection

RESEARCH QUESTION

Does magnetic-activated cell sorting (MACS) for sperm selection increase cumulative live birth rates (CLBR) or improve clinical parameters of reproductive success in couples undergoing intracytoplasmic sperm injection (ICSI) with donor oocytes?

DESIGN

Retrospective multicentre observational study including data compiled from unselected couples who underwent ICSI cycles with donated oocytes in 15 Spanish IVIRMA fertility clinics (January 2008 to February 2020). Patients were divided into reference (standard semen processing, n = 40,157) and MACS (additional sperm selection step by MACS, n = 1,240) groups. CLBR were plotted on Kaplan-Meier curves and compared using the Mantel-Cox test. Proportions were compared with a generalized estimating equation model, and results were adjusted to clinically relevant variables.

RESULTS

The MACS group showed a 27.1% CLBR after one embryo was transferred and 81.6% after four; the reference group had CLBR of 19.6% and 78.5%, respectively. CLBR in the MACS group was 4.2% after five oocytes were used and 75.5% after 15; for the reference group, CLBR were 7.8% and 78.3%, respectively. Kaplan-Meier curves showed statistically significant differences in CLBR per number of embryos transferred and per number of donated metaphase II oocytes between the two groups (both P < 0.0001), but not for CLBR per embryo transfer. No significant differences between groups were found for classical clinical outcomes such as pregnancy and live birth rates per embryo transfer.

CONCLUSIONS

Although MACS sperm selection slightly increased the CLBR per embryo transferred compared with the reference group, this change was not clinically meaningful. MACS should not be recommended indiscriminately to all infertile patients undergoing ICSI with donated oocytes as a sperm processing add-on.

Sperm Selection by Magnetic-Activated Cell Sorting before Microinjection of Autologous Oocytes Increases Cumulative Live Birth Rates with Limited Clinical Impact: A Retrospective Study in Unselected Males

Simple Summary

Many couples attending infertility clinics still need to repeat treatments and undergo several failed attempts before achieving a healthy newborn, which leaves room for improvement in the techniques we currently use in the clinic. Among the different procedures susceptible to improvement, the selection of the most adequate sperm to be injected inside the egg is crucial to the cycle’s success. Magnetic-activated cell sorting (MACS) is a technique that removes physiologically abnormal sperm that have started a programmed cell death (apoptotic) process from a semen sample. However, it is not recommended to all patients because there is no agreement between the published literature on whether it improves reproductive outcomes. This study used data from all intracytoplasmic sperm injection cycles performed using the patient’s own oocytes in our clinics from January 2008 to February 2020. Our findings support that MACS should not be recommended to all infertile couples, since there was no significant difference in results compared to treatments in which MACS was not used. This study provides clinicians and patients with more accurate information on how MACS will impact their chances of pregnancy, and it will lead to studies focused on specific populations to which the technique can be particularly helpful.

Abstract

The application of MACS non-apoptotic sperm selection in infertility clinics is controversial since the published literature does not agree on its effect on reproductive outcomes. Therefore, it is not part of the routine clinical practice. Classical measures of reproductive success (pregnancy or live birth rates per ovarian stimulation) introduce a bias in the evaluation of a technique’s effect, since only the best embryo is transferred. This retrospective, multicenter, observational study evaluated the impact of MACS on reproductive outcomes, measuring results in classical parameters and cumulative live birth rates (CLBR). Data from ICSI cycles using autologous oocyte in Spanish IVIRMA fertility clinics from January 2008 to February 2020 were divided into two groups according to their semen processing: standard practice (reference: 46,807 patients) versus an added MACS sperm selection (1779 patients). Only when measured as CLBR per embryo transferred and per MII oocyte used was the difference between groups statistically significant. There were no significant differences between MACS and reference groups on pregnancy and live birth rates. In conclusion, results suggest that non-apoptotic sperm selection by MACS on unselected males prior to ICSI with autologous oocytes has limited clinical impact, showing a subtle increase in CLBR per embryo transferred.

An update on the techniques used to measure oxidative stress in seminal plasma

Reactive oxygen species (ROS) are produced in significant amounts by spermatozoa and leucocytes. They are necessary to carry out various physiological functions such as sperm capacitation, hyperactivation, acrosome reaction, sperm-zona binding and cellular signalling pathways. Oxidative stress (OS) results when the ROS levels overwhelm the available antioxidant reserve. A number of direct and indirect tests have been developed to assess oxidative stress. In this manuscript, we discuss these common direct and indirect tests as well as their advantages and disadvantages. Tests measuring sperm dysfunction secondary to oxidative stress such as lipid peroxidation, DNA fragmentation and protein alterations are also described.

Characteristics of seasonal spermatogenesis in the soft-shelled turtle

Spermatogenesis in reptiles is a seasonally dependent physiological process that is not temporally associated with male mating behavior. Characteristics of seasonal spermatogenesis in reptiles, however, remain largely unknown. In this review, there is a coverage of the characteristics of soft-shelled turtle, Pelodiscus sinensis, during seasonal spermatogenesis that provides insights into spermatogenesis of testudines. The seminiferous epithelium of P. sinensis are undergoing spermatogenesis during the summer and fall, but are quiescent throughout the rest of the year; germ cells progress through spermatogenic stages in a temporal rather than a spatial pattern. While apoptotic germ cells mainly appear in the non-spermatogenic phase, these are seldom present during active spermatogenesis. It is inferred that apoptosis may be one of the reasons for germ cell loss during the resting phase of spermatogenesis. During the period when spermatogenesis is occurring, Sertoli cells become very narrow and are in contact with several round/elongated spermatids. Many residual spermatozoa can be internalized and degraded within Sertoli cells by entosis during the non-spermatogenic phase, which precedes the next reproductive cycle in P. sinensis. In the late spermatogenic phase, round-shaped mitochondria of spermatids become elongated and swollen, subsequently forming a crescent-like shape and develop into "onion-like" shaped mitochondria. As spermiogenesis progresses, the endoplasmic reticulum of spermatids is transferred into a specialized structure called the "Chrysanthemum flower center", which may be a source of autophagosomal membranes. The information provided in this review will help improve understanding of characteristics of seasonal spermatogenesis, which will hopefully promote interest in the study of reptilian species.

Does myoinositol supplement improve sperm parameters and DNA integrity in patients with oligoasthenoteratozoospermia after the freezing-thawing process?

Sperm cryopreservation is a routine method in andrology and IVF laboratory. However, the sperm quality and its fertilizing capacity have been decreased during this process. The purpose of this experiment was to determine the role of myoinositol as a supplement in amelioration of total and progressive sperm motility, DNA fragmentation, total antioxidant capacity (TAC), reactive oxygen species (ROS), and lipid peroxidation after the freezing-thawing process on patients with oligoasthenoteratozoospermia (OAT) syndrome. Semen samples obtained from 40 patients were divided into two aliquots and freezed with simple and 2 mg/mL myoinositol (MYO) supplemented freezing media. All samples were thawed and assessed after one month. Semen parameters were analyzed in terms of the motility by CASA, the level of total ROS by fluorimetry, TAC and MDA by colorimetric assay and finally DNA fragmentation by TUNEL assay. Our results clearly showed that MYO could improve total (37.46 vs. 12.91, p < 0.001) and progressive motility (21.92 vs. 6.49, p < 0.001) in experimental group compared to control group. A higher TAC level was observed in the MYO treated group in comparison to control group (1.11 vs. 0.91, p = 0.05). While MYO supplementation could not be effective on ROS level, it reduced DNA fragmentation of sperm after freeze-thaw process (p = 0.01). Therefore, MYO could be a good supplement for sperm freezing to reduce the detrimental effects of freezing process especially on DNA integrity, which is an important factor in the success of ART, in OAT suffered patients.

A commercial Roundup® formulation induced male germ cell apoptosis by promoting the expression of XAF1 in adult mice

Roundup® is extensively used for weed control worldwide. Residues of this compound may lead to side effects of the male reproductive system. However, the toxic effects and mechanisms of Roundup® of male germ cells remain unclear. We aimed to investigate the apoptosis-inducing effects of Roundup® on mouse male germ cells and explore the role of a novel tumor suppressor XAF1 (X-linked inhibitor of apoptosis-associated factor 1) involved in this process. We demonstrated that Roundup® can impair spermatogenesis, decrease sperm motility and concentration, and increase the sperm deformity rate in mice. In addition, excessive apoptosis of germ cells accompanied by the overexpression of XAF1 occurred after Roundup® exposure both in vitro and in vivo. Furthermore, the low expression of XIAP (X-linked inhibitor of apoptosis) induced by Roundup® was inversely correlated with XAF1. Moreover, the knockdown of XAF1 attenuated germ cell apoptosis, improved XIAP expression and inhibited the activation of its downstream target proteins, caspase-3 and PARP, after Roundup® exposure. Taken together, our data indicated that XAF1 plays an important role in Roundup®-induced male germ cell apoptosis. The present study suggested that Roundup® exposure has potential negative implications on male reproductive health in mammals.

Odorant receptor might be related to sperm DNA integrity in Apis cerana cerana

Olfactory receptors (ORs) are important for insects to recognize and discriminate odorants in the environment and are mainly expressed in olfactory and gustatory organs. Little is known about the potential OR functions in non-olfactory tissues. In the present study, we evaluated the possibility of odorant receptors AcerOr1 and AcerOr2 (AcerOr2 is orthologous to the co-receptor) mediating sperm DNA integrity, and the relationship between sperm DNA integrity and semen parameters in Apis cerana cerana. Based on previous findings in mammals, we speculated that the Ca²⁺/calmodulin (CaM)/CaM-dependent protein kinase II (CaMKII) signaling pathway might be involved in the regulation of sperm motility in A. cerana cerana. The results showed that both AcerOr1 and AcerOr2 are expressed in the sperms and testis, that components associated with the putative Ca²⁺/CaM/CaMKII signaling pathway are present in A. cerana cerana sperms, and that at least CaM and CaMKII are localized in the sperms and testis. The AcerOr2 agonist VUAA1 significantly improved sperm motility parameters and apoptosis of sperm cells effect DNA integrity, whereas the CaM inhibitor W7 decreased sperm motility parameters and apoptosis of sperm cells, which affects DNA integrity. We also found a positive correlation between sperm DNA integrity and semen quality. These results indirectly as well as directly suggest that OR-mediated sperm responses and the Ca²⁺/CaM/CaMKII signaling pathway might affect semen quality and might be useful in regulating insect reproduction in future.

Influence of iodine in excess on seminiferous tubular structure and epididymal sperm character in male rats

Excess iodine induced public health problems are now emerging in many iodine sufficient regions for indiscriminate intake of iodine through various iodized products. It has been reported that excess iodine can disrupt overall male reproductive physiology by generating oxidative stress in the testis. However, information on the possible effect of iodine in excess on spermatozoa found less. In the present investigation flow cytometric techniques and scanning electron microscopy (SEM) have been used to study the spermatozoal functional as well as structural status under the influence of excess iodine; generation of ROS in the spermatozoa as evident by DCFDA, altered acrosomal integrity as observed by fluorescence lectin staining method and depolarized mitochondrial membrane potential (ΔΨ_m ) noticed by JC-1 staining. Ultrastructure of seminiferous tubule after excess iodine exposure indicated severe deterioration of seminiferous tubular surface architecture. Significant increase in spermatozoal DNA fragmentation and apoptotic sperms were found by acridine orange and Annexin V, respectively, however the plasma membrane integrity/viability was decreased as evident by propidium iodide staining in various incremental doses and durations under iodine excess. The study reveals that excess iodine could cause apoptosis of spermatozoal cells by inducing ROS that ultimately affects male fertility potential.

Free radical and superoxide reactivity detection in semen quality assessment: past, present, and future

Oxidative stress is a well-established cause of male infertility, with reactive oxygen species (ROS) impairing sperm production, motility, membrane, and DNA integrity. Currently, most clinics do not test infertile patients for the imbalance between ROS generation and the ability of the antioxidants to scavenge them, although there is a clear need for andrology laboratories to be able to identify and/or quantify seminal oxidative stress. As such there is a clinical urgency for an inexpensive and easy-to-perform assay able to identify oxidative stress in semen. The aim of this review is to provide information on the currently available methods to assess and quantify ROS and particularly superoxide in male reproductive cells, tissues, and fluids which may have a significant clinical utility in identifying men with impaired fertility associated with oxidative stress. Through a deeper understanding of oxidative stress and its assessment options, clinical andrology labs may better assist patients to achieve increased rates of fertility and pregnancy.

Molecular and Cellular Mechanisms of Apoptosis during Dissociated Spermatogenesis

Apoptosis is a tightly controlled process by which tissues eliminate unwanted cells. Spontaneous germ cell apoptosis in testis has been broadly investigated in mammals that have an associated spermatogenesis pattern. However, the mechanism of germ cell apoptosis in seasonally breeding reptiles following a dissociated spermatogenesis has remained enigmatic. In the present study, morphological evidence has clearly confirmed the dissociated spermatogenesis pattern in Pelodiscus sinensis. TUNEL and TEM analyses presented dynamic changes and ultrastructural characteristics of apoptotic germ cells during seasonal spermatogenesis, implying that apoptosis might be one of the key mechanisms to clear degraded germ cells. Furthermore, using RNA-Seq and digital gene expression (DGE) profiling, a large number of apoptosis-related differentially expressed genes (DEGs) at different phases of spermatogenesis were identified and characterized in the testis. DGE and RT-qPCR analysis revealed that the critical anti-apoptosis genes, such as Bcl-2, BAG1, and BAG5, showed up-regulated patterns during intermediate and late spermatogenesis. Moreover, the increases in mitochondrial transmembrane potential in July and October were detected by JC-1 staining. Notably, the low protein levels of pro-apoptotic cleaved caspase-3 and CytC in cytoplasm were detected by immunohistochemistry and western blot analyses, indicating that the CytC-Caspase model might be responsible for the effects of germ cell apoptosis on seasonal spermatogenesis. These results facilitate understanding the regulatory mechanisms of apoptosis during spermatogenesis and uncovering the biological process of the dissociated spermatogenesis system in reptiles.

The effects of three different exercise modalities on markers of male reproduction in healthy subjects: a randomized controlled trial

The aim of this study was to investigate the effects of moderate-intensity continuous training (MICT), high-intensity continuous training (HICT) and high-intensity interval training (HIIT) on markers of male reproduction including seminal markers of oxidative stress and inflammation as well as semen quality and sperm DNA integrity in healthy human subjects. A total of 397 healthy male volunteers were screened and 280 were randomly assigned to one of the MICT (n = 70), HICT (n = 70), HIIT (n = 70) and non-exercise (NON-EX, n = 70) groups. Subjects had inflammatory markers (IL-1β, IL-6, IL-8 and TNF-α), oxidants (ROS, MDA and 8-isoprostane), antioxidants (SOD, catalase and TAC), semen parameters and sperm DNA damage measured at baseline (T1), the end of week 12 (T2), the end of week 24 (T3), and 7 (T4) and 30 days (T5) after training. Chronic MICT, HICT and HIIT attenuated seminal markers of oxidative stress and inflammation with different kinetics for the three types of exercise (P < 0.05), and these changes were correlated with favorable improvements in semen quality parameters and sperm DNA integrity (P < 0.05). MICT was superior to HICT and HIIT in the improvements of markers of male reproductive function (P < 0.05). In conclusion, different exercise modalities favorably affect markers of male reproduction with different kinetics, suggesting intensity-, duration- and type-dependent adaptations to exercise training in healthy human subjects.

Assessment of Sperm Deoxyribose Nucleic Acid Fragmentation Using Sperm Chromatin Dispersion Assay

The integrity of sperm deoxyribose nucleic acid (DNA) is one of the determinants that ensure normal fertilization, implantation, pregnancy, and the generation of a healthy progeny. Assessment of sperm DNA fragmentation has gained importance as a tool to provide significant information regarding sperm quality, and it can independently predict sperm fertilizing potential. The sperm chromatin dispersion (SCD) assay is one of the available techniques to detect sperm DNA damage with results comparable to the gold standard – Sperm Chromatin Structure Assay. We present here a detailed methodology of an alkaline modification of SCD that can be carried out with minimal laboratory equipment. The SCD assay is a modified halo assay that utilizes chemical methods to demonstrate sperm DNA fragmentation. It involves the embedding of sperms in an agarose medium followed by exposure to alkaline denaturation and deproteinization. The results are interpreted under a light microscope. A visual scoring system is utilized to differentiate the sperms with possible DNA fragmentation from those without fragmented DNA and to determine the sperm DNA fragmentation index (SDFI) % for each semen sample. The SDFI % is directly proportional to the quality of sperm. The SCD assay is a simple, cost-effective, and reliable technique that can detect sperm DNA fragmentation, thus providing information regarding sperm functional quality and reproductive capacity. It is of significance in clinical and research areas of andrology and reproductive medicine, toxicology, and pharmacotherapeutics.

Evaluation of morphological criteria of sperm quality before in vitro fertilization and intracytoplasmic sperm injection

The quality of sperm has a direct influence on the fertilization and developmental competence of embryos. In the literature we did not find defined criteria for evaluation of normal sperm parameters in various species of domestic mammals. Therefore we attempted to review evaluation of criteria of morphologically normal human sperm and their abnormalities. All sperm cells observed in the stained sample are classified as normal or abnormal. Any abnormalities in morphology of sperm have a negative effect on the outcome in in vitro fertilization and intracytoplasmic sperm injection. Abnormal sperm are categorized into subgroups according to the observed defects (concerning the head and/or midpiece and/or tail). Most morphologically abnormal sperm have multiple defects. This article can be considered as guideline for the manual of sperm quality evaluation in different species of domestic mammals.

Sperm DNA damage: how relevant is it clinically?

PURPOSE OF REVIEW

The true impact of the current sperm DNA fragmentation testing needs further scrutiny to assess whether clinically meaningful information is conveyed.

RECENT FINDINGS

Various studies have suggested different or no threshold values with assorted tests for the percentage of DNA fragmentation in the ejaculated sperm above which natural conception, fertilization or embryo development and/or clinical pregnancy rates are compromised. Current DNA fragmentation assessment methods provide very little specific information on the nature and severity of the DNA damage detected. Although sperm DNA fragmentation is associated with lower pregnancy rates through natural conception or intrauterine insemination, it does not seem to affect intracytoplasmic sperm injection outcome. Although animal studies demonstrated adverse reproductive effects of sperm DNA fragmentation, any conclusive evidence in humans is yet to be demonstrated. It is not clear whether interventions aimed at enrichment of sperm with decreased DNA fragmentation are effective in preventing the potential adverse effects of sperm DNA fragmentation in humans. Major concern about the use of sperm DNA integrity tests as prognostic parameters is that the direct evaluation of DNA fragmentation in individual sperm fertilizing the oocyte is not possible.

SUMMARY

The lack of consensus in defining a clinically relevant standard DNA fragmentation test with a meaningful cut-off level brings challenges in implementing the routine use of sperm DNA integrity assessment in daily practice.

TUNEL as a test for sperm DNA damage in the evaluation of male infertility

OBJECTIVES

To standardize the TUNEL assay by establishing inter- and intraobserver variability, interassay variability, cutoff values, sensitivity and specificity of the assay, and studying the distribution of the DNA damage in a population of infertile men referred to a clinical andrology laboratory.

METHODS

Seminal ejaculates from 25 healthy male volunteers (controls) and 194 infertile men (with male factor infertility) referred to an andrology laboratory were examined for DNA damage by TUNEL assay using flow cytometric analysis.

RESULTS

Both the inter- and intraobserver variability and interassay variability was small (<10%). DNA damage in the controls was 11.9 ± 6.8% vs. 29.5 ± 18.7% in patients (P <.001). The cut-off value of 19.25% maximized the observed sensitivity (64.9%) and specificity (100%) of the assay. The distribution of DNA damage in the patients was as follows: 14.9% (29 of 194) with DNA damage between 0% and 10%; 22.7% (44 of 194) between 10% and 20%; 8.8% (17 of 194) between 20% and 30%; and 17.5% (34 of 194) between 30% and 40%. Finally, 27.3% (53 of 194) had TUNEL values >40%.

CONCLUSIONS

We report a detailed standardization of the TUNEL assay for clinical use, as well as reference ranges for DNA damage in normal healthy donors and infertile men. A cut-off of 19.25% with observed 100% specificity established in our program can differentiate infertile men with DNA damage from healthy men. This test can be offered to infertile patients who are idiopathic, have severe oxidative stress-related abnormal semen quality, and contribute to the infertility problem of the couple who are considering assisted reproductive techniques.

Testicular sperm from patients with obstructive and nonobstructive azoospermia: aneuploidy risk and reproductive prognosis using testicular sperm from fertile donors as control samples

OBJECTIVE

To establish a baseline incidence of chromosomal abnormalities in testicular sperm of fertile men and to determine the best control sample for comparisons with azoospermic males to estimate their reproductive prognosis.

DESIGN

Prospective study.

SETTING

Infertility clinic.

PATIENT(S)

Sixteen obstructive azoospermic (OA) and 19 nonobstructive azoospermic patients (NOA). Control samples were ejaculated sperm from ten fertile donors and testicular sperm from ten other fertile donors.

INTERVENTION(S)

Fluorescence in situ hybridization (FISH) in sperm.

MAIN OUTCOME MEASURE(S)

Sperm numerical abnormalities for chromosomes 13, 18, 21, X, and Y; ongoing implantation and pregnancy rates in intracytoplasmic sperm injection (ICSI) cycles.

RESULT(S)

In control samples, testicular sperm showed higher incidences of diploidy (0.27% vs. 0.10%) and disomy for chromosomes 13 (0.16% vs. 0.07%), 21 (0.25% vs. 0.12%), and sex chromosomes (0.34% vs. 0.21%) than ejaculated sperm. Comparisons with ejaculated control samples showed 12.5% OA and 68.4% NOA patients having significantly higher incidence of sperm chromosomal abnormalities. Compared with testicular control subjects, fewer OA (6.3%) and NOA (42.1%) patients had chromosomally abnormal sperm. NOA patients had lower ongoing implantation and pregnancy rates than OA patients, particularly those with abnormal FISH compared with testicular control samples.

CONCLUSION(S)

Sperm FISH analysis using testicular sperm control samples better identifies NOA patients with a lower likelihood of reproductive success.

The effect of age on the expression of apoptosis biomarkers in human spermatozoa

OBJECTIVE

To evaluate the impact of age on the expression of apoptotic biomarkers in human spermatozoa.

DESIGN

Cross sectional, prospective study.

SETTING

Academic centers.

PATIENT(S)

Healthy volunteers with proven fertility, stratified by age (n = 25, range: 20-68 years).

INTERVENTION(S)

Examination of serum hormone levels and basic semen parameters, and assessment of early (plasma membrane translocation of phosphatidylserine) and late (DNA fragmentation) sperm apoptotic markers by flow cytometry (using Annexin-V binding and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling).

MAIN OUTCOME MEASURE(S)

Apoptosis markers.

RESULT(S)

Advancing male age was significantly and positively correlated with Annexin-V binding results. Although not significant, there was a clear trend for increased DNA fragmentation in the older groups. The age threshold for these observations appears to be 40 years. Advancing male age was positively correlated with FSH and sex hormone-binding globulin (SHBG) levels, and negatively correlated with sperm concentration.

CONCLUSION(S)

Advancing male age is associated with the expression of early apoptotic markers as evidenced by significantly increased plasma membrane translocation of phosphatidylserine, as well as with a more subtle proportion of sperm carrying DNA fragmentation. This study confirmed that male age is also associated with a decline in sperm concentration.

Potential biological role of poly (ADP-ribose) polymerase (PARP) in male gametes

Maintaining the integrity of sperm DNA is vital to reproduction and male fertility. Sperm contain a number of molecules and pathways for the repair of base excision, base mismatches and DNA strand breaks. The presence of Poly (ADP-ribose) polymerase (PARP), a DNA repair enzyme, and its homologues has recently been shown in male germ cells, specifically during stage VII of spermatogenesis. High PARP expression has been reported in mature spermatozoa and in proven fertile men. Whenever there are strand breaks in sperm DNA due to oxidative stress, chromatin remodeling or cell death, PARP is activated. However, the cleavage of PARP by caspase-3 inactivates it and inhibits PARP's DNA-repairing abilities. Therefore, cleaved PARP (cPARP) may be considered a marker of apoptosis. The presence of higher levels of cPARP in sperm of infertile men adds a new proof for the correlation between apoptosis and male infertility. This review describes the possible biological significance of PARP in mammalian cells with the focus on male reproduction. The review elaborates on the role played by PARP during spermatogenesis, sperm maturation in ejaculated spermatozoa and the potential role of PARP as new marker of sperm damage. PARP could provide new strategies to preserve fertility in cancer patients subjected to genotoxic stresses and may be a key to better male reproductive health.