Showing papers on "Semen published in 2002"
TL;DR: High loads of DNA damage measured by the Comet assay were predictive of failure of embryo development after ICSI, and it is likely that sperm with DNA damage contributed to successful fertilization and in-vitro development.
Abstract: Background The integrity of sperm DNA is important for the success of natural or assisted fertilization, as well as normal development of the embryo, fetus and child. ICSI, by bypassing sperm selection mechanisms, increases the risk of transmitting damaged DNA and the significance of this requires investigation. Methods DNA damage in sperm from an unselected group of 60 men undergoing IVF treatment was measured by single cell gel electrophoresis (Comet assay) and correlated with semen and treatment cycle parameters. Results Wide spectra of sperm DNA damage were found both within and between men but no specific subgroups were identified. Semen and treatment cycle parameters were not different in men grouped according to high or low sperm DNA damage. However, regression analysis showed that DNA damage was positively associated with age (29-44 years), abnormal sperm and motility and negatively associated with sperm concentration. In ICSI cycles DNA damage was positively associated with impairment of post-fertilization embryo cleavage. Conclusions This study contributes to the evidence of DNA damage within sperm. High loads of DNA damage measured by the Comet assay were predictive of failure of embryo development after ICSI. As it is likely that sperm with DNA damage contributed to successful fertilization and in-vitro development, potential adverse effects remain to be clarified.
506 citations
TL;DR: In this article, the authors reviewed aspects of sperm cryopreservation paralleled by events of capacitation and evaluated the possible roles of sperm membrane cholesterol, reactive oxygen species, and seminal plasma as mediators of sperm function.
488 citations
TL;DR: It is proposed that the presence of DNA damage is not directly linked to an apoptotic process occurring in spermatozoa and arises due to problems in the nuclear remodeling process, and may be linked to defects in cytoplasmic remodeling during the later stages of spermatogenesis.
Abstract: Numerous studies have shown the presence of DNA strand breaks in human ejaculated spermatozoa. The nature of this nuclear anomaly and its relationship to patient etiology is however poorly understood. The aim of this study was to investigate the relationship between nuclear DNA damage, assessed using the TUNEL assay and a number of key apoptotic markers, including Fas, Bcl-x, and p53, in ejaculated human spermatozoa from men with normal and abnormal semen parameters. We also determined the nature of the DNA damage by examining the percentage of ejaculated spermatozoa exhibiting DNA damage using the comet assay and by challenging sperm chromatin to attack by micrococcal nuclease S7 and DNase I. We show that TUNEL positivity and apoptotic markers do not always exist in unison; however, semen samples that had a low sperm concentration and poor morphology were more likely to show high levels of TUNEL positivity and Fas and p53 expression. In addition, the DNA damage in ejaculated human sperm is represented by both single- and double-stranded DNA breaks, and access to the DNA is restricted by the compacted nature of ejaculated spermatozoa. This DNA protection is poorer in men with abnormal semen parameters. We propose that the presence of DNA damage is not directly linked to an apoptotic process occurring in spermatozoa and arises due to problems in the nuclear remodeling process. Subsequently, the presence of apoptotic proteins in ejaculated spermatozoa may be linked to defects in cytoplasmic remodeling during the later stages of spermatogenesis.
449 citations
TL;DR: Sperm morphology, motility, mitochondrial activities and viability are equally susceptible to cryopreservation-induced damage and R123 intensity is a novel and robust indicator of mitochondrial function before and after such trauma.
Abstract: BACKGROUND: The effects of cryoinjury were determined simultaneously on the mitochondrial function, motility, morphology and viability of ejaculated human sperm. METHOD: Rhodamine 123 (R123) uptake (% of sperm) and stain intensity were used to determine sperm mitochondrial activity before and after cryopreservation from the semen of 50 men attending for infertility investigation. Morphology was assessed using Tygerberg’s strict criteria and viability was assessed by eosin Y. Sperm motility was measured using computer-assisted semen analysis (CASA). RESULTS: Freeze–thawing caused a 37% (P 0.001) reduction in normal morphological forms of sperm. All CASA sperm motility parameters except amplitude of lateral head displacement were similarly reduced. R123 uptake and intensity within sperm mitochondria decreased by 36 and 47% respectively (both P 0.001). In addition, there was a similar significant decrease (31%, P 0.001) in the viability of the sperm. CONCLUSIONS: Sperm morphology, motility, mitochondrial activities and viability are equally susceptible to cryopreservationinduced damage. R123 intensity is a novel and robust indicator of mitochondrial function before and after such trauma.
404 citations
TL;DR: Analysis of mitochondrial membrane potential is the most sensitive test by which to determine sperm quality, and these findings promise development of a test that may help to predict successful IVF.
Abstract: Background Sperm cell death appears to be a cause of male infertility. The objective of this study was to determine the most reliable method for the evaluation of sperm quality in semen samples during sperm preparation for IVF. Methods Conventional analysis of semen samples was compared with several cytofluorometric methods detecting death-associated changes. Neat semen from infertile patients and sperm prepared by PureSperm gradient were studied by conventional microscopy and analysed for mitochondrial membrane potential (Delta Psi(m)), generation of reactive oxygen species, DNA fragmentation and cell viability. Results In neat semen, a positive correlation was found between the percentage of Delta Psi(m)(high) sperm cells and standard semen parameters (concentration/motility). Sperm cells depicting Delta Psi(m)(high) and cells with low DNA fragmentation displayed high fertilization rate after IVF. The only changes that could be detected in prepared sperm were changes in Delta Psi(m), with Delta Psi(m)(high) sperm positively correlated with forward motility and also with high fertilization rates after IVF. Conclusion Analysis of mitochondrial membrane potential is the most sensitive test by which to determine sperm quality. These findings promise development of a test that may help to predict successful IVF.
366 citations
TL;DR: The number of follicles, age of the woman/man and sperm DNA quality may predict IUI outcome, and the percentage of sperm with acid- + heat-resistant DNA were the parameters that predicted IUI outcomes in most of these data subsets.
Abstract: Background We aimed to investigate whether sperm DNA quality may predict intrauterine insemination (IUI) outcome. Methods The study was designed in a prospective cohort fashion, at a tertiary centre for reproductive medicine. A total of 119 patients underwent 154 cycles of IUI. Parameters related to demography, cycle management and semen sample used for IUI were evaluated. Conventional semen parameters, morphology (strict criteria), sperm DNA fragmentation and stability [evaluated by terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling (TUNEL) and acridine orange staining under both acid and acid + heat denaturing conditions respectively] were measured. The main outcome measure was clinical pregnancy, defined as ultrasonographic visualization of intrauterine gestational sac(s). Results Logistic regression analyses were done on six sets of data, including all cycles combined, cycles with washed samples, first cycle of each couple, first cycle of each couple with washed samples, cycles stimulated with gonadotrophins and finally gonadotrophin-stimulated cycles with washed samples. The number of pre-ovulatory follicles on day of hCG, the age of the woman and the percentage of sperm with acid- + heat-resistant DNA were the parameters that predicted IUI outcome in most of these data subsets. For the gonadotrophin-stimulated cycles, age of the man appeared as a predictor as opposed to that of the woman; and for the cycles within this subgroup, where the semen sample was washed, sperm DNA fragmentation and age of the man were the only two parameters to predict IUI outcome. No samples with >12% of sperm having DNA fragmentation resulted in pregnancy. Conclusions The number of follicles, age of the woman/man and sperm DNA quality may predict IUI outcome.
362 citations
TL;DR: Infertile men who smoke cigarettes have higher levels of seminal OS than infertile nonsmokers and physicians should advise infertiles men who smoked cigarettes to quit, given the potential adverse effects of seminalOS on fertility.
355 citations
TL;DR: Total normal sperm count increases after combined zinc sulfate and folic acid treatment in both subfertile and fertile men, and this finding opens avenues of future fertility research and treatment and may affect public health.
348 citations
TL;DR: It is suggested that the presence of apoptotic spermatozoa in fresh semen could be one of the reasons for poor fertility in breeding bulls.
Abstract: The present study was conducted to detect sperm apoptosis in fresh and frozen semen and to determine its relationship with bull fertility. Three ejaculates were collected from five breeding bulls with different fertility levels and were cryopreserved using standard methods. Two flow cytometric methods were employed to measure apoptosis: an assay for phosphatidylserine (PS) translocation across the plasma membranes using fluorescein-labeled Annexin V and propidium iodide (PI), and an assay for nicked DNA using bromodeoxyuridine (BrdU), terminal deoxynucleotidyl transferase, and fluorescein-labeled anti-BrdU monoclonal antibody. Both assays showed that fresh sperm contained 10%-20% apoptotic sperm. Significant differences in the percentage of apoptotic sperm were observed among the bulls. Cryopreservation induced translocation of PS to the outer leaflet of the plasma membrane and caused most of the necrotic cells in fresh sperm to disintegrate. Bull fertility was significantly related to the percentage of necrotic or viable sperm in fresh semen as detected by the Annexin V/PI assay, to the number of apoptotic sperm in fresh semen as detected by the TUNEL assay, and to the level of chromatin or DNA condensation as detected by PI staining. The present study suggests that the presence of apoptotic spermatozoa in fresh semen could be one of the reasons for poor fertility in breeding bulls.
335 citations
TL;DR: Sperm concentration was significantly lower in Columbia, Missouri, than in New York, New York; Minneapolis, Minnesota; and Los Angeles, California, and between-center differences remained significant in multivariate models that controlled for abstinence time, semen analysis time, age, race, smoking, history of sexually transmitted disease, and recent fever.
Abstract: Although geographic variation in semen quality has been reported, this is the first study in the United States to compare semen quality among study centers using standardized methods and strict quality control. We evaluated semen specimens from partners of 512 pregnant women recruited through prenatal clinics in four U.S. cities during 1999-2001; 91% of men provided two specimens. Sperm concentration, semen volume, and motility were determined at the centers, and morphology was assessed at a central laboratory. Study protocols were identical across centers, and quality control was rigorously maintained. Sperm concentration was significantly lower in Columbia, Missouri, than in New York, New York; Minneapolis, Minnesota; and Los Angeles, California. Mean counts were 58.7, 102.9, 98.6, and 80.8 X 10(6)/mL (medians 53.5, 88.5, 81.8, and 64.8 X 10(6)/mL) in Missouri, New York, Minnesota, and California, respectively. The total number of motile sperm was also lower in Missouri than in other centers: 113, 196, 201, and 162 X 10(6) in Missouri, New York, Minnesota, and California, respectively. Semen volume and the percent morphologically normal sperm did not differ appreciably among centers. These between-center differences remained significant in multivariate models that controlled for abstinence time, semen analysis time, age, race, smoking, history of sexually transmitted disease, and recent fever (all p-values < 0.01). Confounding factors and differences in study methods are unlikely to account for the lower semen quality seen in this mid-Missouri population. These data suggest that sperm concentration and motility may be reduced in semirural and agricultural areas relative to more urban and less agriculturally exposed areas.
292 citations
TL;DR: Despite high costs and complex procedures, sexing spermatozoa, usually followed by cryopreservation, is being used commercially for cattle and horse production in several countries, and is used to produce girls to avoid X-chromosome-linked genetic diseases.
Abstract: Thousands of offspring have now been produced via artificial insemination with spermatozoa sexed by flow cytometry and cell sorting. We are unaware of any other practical approach to sexing spermatozoa that maintains fertility. Accuracy of sexing usually is 85-95% in most species, but somewhat lower with human spermatozoa. Spermatozoa are sexed in series, one at a time, at routine rates of about 3000 live spermatozoa of each sex per second for most species, and nearly twice that rate under optimal conditions for some species. Owing to various constraints and statistical considerations, there appears to be an upper theoretical limit to sexing spermatozoa of about 10,000 live spermatozoa of each sex per second with current methodology. About a quarter of the spermatozoa processed are sexed; the rest are discarded in the process or lost due to logistical constraints. Spermatozoa undergo some damage during sorting, although much less in terms of viability than with routine cryopreservation; fertility is lower with sexed than control spermatozoa. Offspring from sexed spermatozoa appear to have no more abnormalities than do controls, and both groups grow and thrive similarly. Despite high costs and complex procedures, sexing spermatozoa, usually followed by cryopreservation, is being used commercially for cattle and horse production in several countries, and is used to produce girls to avoid X-chromosome-linked genetic diseases.
TL;DR: The results highlight the importance of sperm morphology parameters and indicate that the effect of proportion of normal sperm on TTP may be independent of sperm concentration.
Abstract: BACKGROUND: In fertile populations, little is known about the association between semen parameters and time to pregnancy (TTP) METHODS: Pregnant women from Copenhagen, Edinburgh, Paris and Turku who conceived without medical intervention were asked for their TTP (942 couples), and their partners provided a semen sample The proportion of morphologically normal sperm and the multiple anomalies index (MAI, ratio of the total number of anomalies to the number of abnormal sperm) were centrally estimated We estimated rate ratios for the occurrence of a pregnancy by a discrete survival model, adjusted for sexual activity and female factors affecting fecundity RESULTS: Increasing sperm concentration influenced TTP up to 5510 6 /ml The proportion of morphologically normal sperm influenced TTP up to 39% according to David’s criteria, and this association held among the subjects with a sperm concentration >5510 6 /ml For strict criteria, the threshold value was 19% normal sperm An increase of 05 in MAI was associated with an adjusted rate ratio for the occurrence of a pregnancy of 068 (95% confidence interval: 054–085) CONCLUSIONS: These results highlight the importance of sperm morphology parameters and indicate that the effect of proportion of normal sperm on TTP may be independent of sperm concentration
TL;DR: A better understanding of the significance and role of TGFβ in semen will facilitate development of novel therapies for immune-based infertility disorders and explain epidemiological observations linking acute and cumulative exposure to semen with successful placental development and pregnancy outcome.
TL;DR: The measurement of MA + 4HA in human spermatozoa provides important information on the underlying quality of spermatogenesis and should be of value in the clinical diagnosis of infertility involving oxidative stress and the selection of patients for antioxidant therapy.
Abstract: A spectrophotometric assay for the measurement of malondialdehyde and 4 hydroxyalkenals (MA + 4HA) has been evaluated for the detection of sperm pathologies involving oxidative stress. In order to make sensitive measurements of MA + 4HA on human spermatozoa, the stimulation of a lipid peroxidation cascade with a ferrous ion promoter was found to be necessary. The optimal configuration for the promoter was defined (0.64 mM FeSO4 + 20 mM ascorbate for 2 h in Ca2+ and Mg2 free Hanks' balanced salt solution) and the assay used in a series of studies to elucidate the functional significance of MA + 4HA determinations. Such measurements were found to give highly significant correlations (p < 0.001) with the loss of motility induced by oxidative stress created either with a xanthine oxidase, free radical generating system or by prolonged incubation under aerobic conditions. Experiments involving the stimulation and suppression of lipid peroxide release from human sperm suspensions, in concert with a bioassay for cytotoxicity, confirmed the strength and causative nature of these associations. Measurements of lipid peroxidation potential in highly purified, leucocyte-free sperm suspensions revealed the presence of inverse correlations with the motility of the spermatozoa, their viability, their competence for sperm-oocyte fusion and, most significantly, the quality of sperm movement in the original semen samples. Similar negative correlations were observed between sperm function and phorbol ester-stimulated reactive oxygen species generation but, unlike the MA + 4HA determinations, these relationships were obfuscated by the presence of leucocytes. We conclude that the measurement of MA + 4HA in human spermatozoa provides important information on the underlying quality of spermatogenesis and should be of value in the clinical diagnosis of infertility involving oxidative stress and the selection of patients for antioxidant therapy.
TL;DR: The probable altruistic behaviour of spermatozoa in an eutherian mammal, Apodemus sylvaticus, is reported, which displayed a unique morphological transformation resulting in cooperation in distinctive aggregations or ‘trains’ of hundreds or thousands of cells, which significantly increased sperm progressive motility.
Abstract: Spermatozoa from a single male will compete for fertilization of ova with spermatozoa from another male when present in the female reproductive tract at the same time. Close genetic relatedness predisposes individuals towards altruism, and as haploid germ cells of an ejaculate will have genotypic similarity of 50%, it is predicted that spermatozoa may display cooperation and altruism to gain an advantage when inter-male sperm competition is intense. We report here the probable altruistic behaviour of spermatozoa in an eutherian mammal. Spermatozoa of the common wood mouse, Apodemus sylvaticus, displayed a unique morphological transformation resulting in cooperation in distinctive aggregations or 'trains' of hundreds or thousands of cells, which significantly increased sperm progressive motility. Eventual dispersal of sperm trains was associated with most of the spermatozoa undergoing a premature acrosome reaction. Cells undergoing an acrosome reaction in aggregations remote from the egg are altruistic in that they help sperm transport to the egg but compromise their own fertilizing ability.
TL;DR: Ejaculate volume, sperm count, progressive motility, normal morphology, and fertilizing capacity were significantly lower in infertile men compared with controls, and PCBs and PEs may be instrumental in the deterioration of semen quality.
TL;DR: Antioxidants generally were not beneficial, except the percentage of motile sperm was improved by 6-11% units when sperm were stored unfrozen or after freezing when 0.5mM of GSH with or without SOD was added, which may have more useful applications in organizations using an egg yolk-based semen extender.
TL;DR: It is proposed that the sequestration of BSP proteins of SP by LDF may represent the major mechanism of sperm protection by EY, and it is shown that the B SP proteins bind to the low-density fraction (LDF), a lipoprotein component of the EY extender.
Abstract: Over the past 60 years, egg yolk (EY) has been routinely used in both liquid semen extenders and those used to cryopreserve sperm. However, the mechanism by which EY protects sperm during liquid storage or from freezing damage is unknown. Bovine seminal plasma contains a family of proteins designated BSP-A1/-A2, BSP-A3, and BSP-30-kDa (collectively called BSP proteins). These proteins are secretory products of seminal vesicles that are acquired by sperm at ejaculation, modifying the sperm membrane by inducing cholesterol efflux. Because cholesterol efflux is time and concentration dependent, continuous exposure to seminal plasma (SP) that contains BSP proteins may be detrimental to the sperm membrane, which may adversely affect the ability of sperm to be preserved. In this article, we show that the BSP proteins bind to the low-density fraction (LDF), a lipoprotein component of the EY extender. The binding is rapid, specific, saturable, and stable even after freeze-thawing of semen. Furthermore, LDF has a very high capacity for BSP protein binding. The binding of BSP proteins to LDF may prevent their detrimental effect on sperm membrane, and this may be crucial for sperm storage. Thus, we propose that the sequestration of BSP proteins of SP by LDF may represent the major mechanism of sperm protection by EY.
TL;DR: Findings support the hypothesis that there is a genetic basis for variation in postthaw semen quality between individuals, and that AFLP technology may be able to identify molecular markers linked to genes influencing this variation.
Abstract: This study investigated two hypotheses: 1) that consistent between-boar variation in frozen semen quality exists and is genetically determined, and 2) molecular markers linked to genes controlling semen freezability can be identified using amplified restriction fragment length polymorphism (AFLP) technology. Five ejaculates were collected from each of 129 boars. Semen was diluted into a commercial freezing buffer (700 mOsm/kg, 3% glycerol) and five straws (0.5 ml) per ejaculate were cryopreserved (to -5 degrees C at 6 degrees C/min, then -5 degrees C to -80 degrees C at 40 degrees C/min). Semen was assessed for percentage of motile cells, motility characteristics (computer-aided semen analysis; CASA), plasma membrane integrity (SYBR-14 positive), and acrosome integrity (positive for fluorescein-labeled peanut agglutinin; PNA). Consistent between-boar variability was detected for postthaw sperm motility (P 0.05) or straws (P > 0.05) for any viability assessment. Multivariate pattern analysis of the viability data set highlighted three groups of boars producing spermatozoa with poor, average, and good postthaw recovery (42, 63, and 24 boars, respectively). DNA from Large White boars (n = 22) previously classified as good and poor freezers was screened for AFLP markers. Twenty-eight polymerase chain reaction primer combinations generated 2182 restriction fragment bands, of which 421 were polymorphic. Sixteen candidate genetic markers (P < 0.005) were identified by comparing the AFLP profile with semen freezability using logistic regression analysis. These findings support the hypothesis that there is a genetic basis for variation in postthaw semen quality between individuals, and that AFLP technology may be able to identify molecular markers linked to genes influencing this variation.
TL;DR: Adverse effects of lead on sperm concentration and susceptibility to acid induced denaturation of sperm chromatin are unlikely at blood lead concentrations below 45 μg/dl, although effects of low level exposure to lead on other measures of testicular function cannot be ruled out.
Abstract: Objectives: To obtain knowledge on male reproductive toxicity of inorganic lead at current European exposure levels and to establish lowest adverse effect levels, if any. Methods: A cross sectional survey of the semen of 503 men employed by 10 companies was conducted in the United Kingdom, Italy, and Belgium. The mean blood lead concentration was 31.0 µg/dl (range 4.6‐64.5) in 362 workers exposed to lead and 4.4 µg/dl (range below the detection limit of 19.8) in 141 reference workers. Semen volume and sperm concentration were determined in a fresh semen sample according to an agreed protocol subject to quality assurance. The sperm chromatin structure assay (SCSA) was performed at a centralised laboratory. Extraneous determinants including centre, period of sexual abstinence, and age were taken into account in the statistical analysis. If appropriate, possible thresholds were examined by iterative threshold slope linear regression. Results: The median sperm concentration was reduced by 49% in men with blood lead concentration above 50 µg/dl. There was no indication of a linear trend of lower sperm concentration with increasing blood lead values, but threshold slope least square regression identified a blood lead concentration of 44 µg/dl (β=-0.037, F=4.35, p=0.038) as a likely threshold. Abnormal sperm chromatin structure was not related to blood lead concentration, but some indications of deterioration of sperm chromatin was found in men with the highest concentrations of lead within spermatozoa. Biological monitoring data did not indicate long term effects of lead on semen quantity or sperm chromatin. Conclusion: Adverse effects of lead on sperm concentration and susceptibility to acid induced denaturation of sperm chromatin are unlikely at blood lead concentrations below 45 µg/dl. Effects of low level exposure to lead on other measures of testicular function cannot be ruled out.
TL;DR: The reproductive impairment recognized in men with diabetes could be the result of interference by the disease on the hypothalamo-pituitary-testicular axis at multiple levels, as indicated by the reduced gonadotrophin response to appropriate stimuli and by the abnormal ultrastructure of ejaculated sperm.
Abstract: BACKGROUND: The objective of the study was to investigate the hypothalamo-pituitary–testicular axis and sperm structure at the transmission electron microscope (TEM) level in men affected by insulin-dependent diabetes. METHODS: Twenty-two diabetic men and 24 controls were recruited. GnRH (100 µg) was administered and FSHand LH-induced secretion was evaluated. Semen samples were collected and sperm concentration and motility were determined using a Makler chamber. Ejaculated sperm were fixed and observed with a TEM. RESULTS: The response of gonadotrophins to GnRH was significantly lower in diabetics than in control men. Sperm motility was also significantly lower. At the electron microscope level, sperm from diabetics exhibited a higher percentage of immaturity- and apoptosis-related defects than sperm from controls. CONCLUSIONS: The reduced response of gonadotrophins to GnRH in diabetic men may indicate a decreased acute releasable pool of pituitary gonadotrophins. The results of TEM examination showed that sperm from men with diabetes presented severe structural defects in comparison with sperm from controls. It is possible that the reproductive impairment recognized in men with diabetes could be the result of interference by the disease on the hypothalamo-pituitary–testicular axis at multiple levels, as indicated by the reduced gonadotrophin response to appropriate stimuli and by the abnormal ultrastructure of ejaculated sperm. The defective spermatogenesis may be the consequence of a direct testicular effect of the disease.
TL;DR: Focusing on the subgroup of men with normal semen quality showed that sperm count and sperm progressive motility were inversely related to the concentrations of PCB metabolites within this group, the first time that a correlation between exposure to environmental pollutants with endocrine-disrupting capacity and human sperm quality has been observed.
Abstract: BACKGROUND: Various studies have been performed in which potential effects of xenoestrogens on fertility or sperm parameters were investigated by comparing groups of subjects exposed to different levels of these chemicals. METHODS: In our study we used an alternative approach, as we selected one group of men with very poor semen quality and another group with normal semen quality and determined the blood organochlorine contents in order to determine whether a difference in these levels could be established. Organochlorine compounds, including polychlorinated biphenyls (PCB) and PCB metabolites, were detected using gas chromatography. The concentrations were compared between both groups, and related to semen parameters. RESULTS: A comparison of both groups did not reveal significant differences in organochlorine levels. Linear relationships were found when PCB and metabolite concentrations were related to the age of the volunteers. Focusing on the subgroup of men with normal semen quality showed that sperm count and sperm progressive motility were inversely related to the concentrations of PCB metabolites within this group. CONCLUSIONS: The finding of a significantly decreased sperm count in relation to an elevated PCB metabolite level within the subgroup of men with normal semen quality is important. This is the first time that a correlation between exposure to environmental pollutants with endocrine-disrupting capacity and human sperm quality has been observed.
TL;DR: It is proposed that Acp62F's protease inhibitor activity exerts positive protective functions in the mated female's reproductive tract but that entry of a small amount of this protein into the female's hemolymph could contribute to the cost of mating.
Abstract: Drosophila melanogaster seminal fluid proteins stimulate sperm storage and egg laying in the mated female but also cause a reduction in her life span. We report here that of eight Drosophila seminal fluid proteins (Acps) and one non-Acp tested, only Acp62F is toxic when ectopically expressed. Toxicity to preadult male or female Drosophila occurs upon one exposure, whereas multiple exposures are needed for toxicity to adult female flies. Of the Acp62F received by females during mating, approximately 10% enters the circulatory system while approximately 90% remains in the reproductive tract. We show that in the reproductive tract, Acp62F localizes to the lumen of the uterus and the female's sperm storage organs. Analysis of Acp62F's sequence, and biochemical assays, reveals that it encodes a trypsin inhibitor with sequence and structural similarities to extracellular serine protease inhibitors from the nematode Ascaris. In light of previous results demonstrating entry of Acp62F into the mated female's hemolymph, we propose that Acp62F is a candidate for a molecule to contribute to the Acp-dependent decrease in female life span. We propose that Acp62F's protease inhibitor activity exerts positive protective functions in the mated female's reproductive tract but that entry of a small amount of this protein into the female's hemolymph could contribute to the cost of mating.
TL;DR: Semen analysis on a male harbouring the A3243G mtDNA mutation is carried out and it is shown that high levels of mutant mtDNA strongly correlate with low sperm motility.
Abstract: Very low levels of somatic mitochondrial (mt)DNA deletions have been identified in the semen of infertile men. It has been suggested that these mutations cause infertility through an effect on sperm motility, but there has been no direct evidence to show that mutant mtDNA can affect sperm function. We have carried out semen analysis on a male harbouring the A3243G mtDNA mutation and show that high levels of mutant mtDNA strongly correlate with low sperm motility.
TL;DR: Comet head and tail DNA parameters appear to be potentially useful as predictors of embryo quality and IVF outcomes, especially in couples with unexplained subfertility.
Abstract: BACKGROUND: Standard semen parameters have proven poor at predicting the outcomes of IVF treatment cycles. As recent studies suggest that the male genome may play an important role in early embryogenesis, this study attempts to correlate the level of sperm DNA damage in fresh semen and prepared sperm with the outcomes of conventional IVF treatment cycles. METHODS: Forty patients embarking on IVF treatment were recruited into this prospective observational study. Both fresh semen and PureSperm ® -prepared sperm were processed using a modified comet assay 3–6 months prior to the patients’ IVF treatment cycles. Comet head DNA (mean and integrated head density) and tail DNA parameters (length and moment) were measured separately. RESULTS: Significant correlations between total sperm concentration and between comet length, moment, mean head density with embryo quality were detected in fresh semen and prepared sperm. Surprisingly, no significant correlations between head and tail parameters were detected. CONCLUSIONS: Comet head and tail DNA parameters appear to be potentially useful as predictors of embryo quality and IVF outcomes, especially in couples with unexplained subfertility. The lack of correlation between head and tail parameters may be due to a different mechanism of DNA damage within these two compartments.
TL;DR: Findings indicate that, compared with women exposed to their partner's sperm cells and seminal fluid, those treated with in-vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) with ejaculated sperm were doubled and the risk of pre-eclampsia tripled in those never exposed to the sperm of their partner.
TL;DR: The increase in chromatin alterations and DNA damage in sperm, as defined by the sperm chromatin structure assay from leukocytospermic samples may be related to alterations in the regulation of spermatogenesis.
TL;DR: This is to the authors' knowledge the first study showing a direct correlation between the seminal PSA levels and sperm motility in a group of men representing the general population, and demonstrated the regulatory effect of post-testicular glands on the motility of sperm.
Abstract: Background Little is known about the regulation of sperm motility, which is an important predictor of male fertility. However, both testicular and post-testicular factors may be involved, although the impact of the latter has been relatively poorly investigated. Methods In semen samples from 301 young men from the general Swedish population (mean +/- SD age 18.2 +/- 0.4 years), we assessed sperm motility by use of a manual method as well as computer-assisted sperm analysis (CASA) and correlated these values to seminal levels of neutral alpha-glucosidase (NAG), prostate-specific antigen (PSA), zinc and fructose. Results There were significant positive correlations between seminal levels of NAG, and PSA and CASA percentage motile sperm (r = 0.158, P = 0.009; r = 0.155, P = 0.01 respectively), and significant negative correlations with CASA percentage immotile sperm (r = -0.206, P = 0.001; r = -0.157, P = 0.009 respectively). In a multiple regression analysis it was found that, apart from sperm concentration, the level of PSA was the most significant and independent parameter in predicting percentage motile sperm (beta = 0.220, P = 0.037). Conclusion Our study demonstrated the regulatory effect of post-testicular glands on the motility of sperm. This is to our knowledge the first study showing a direct correlation between the seminal PSA levels and sperm motility in a group of men representing the general population. In future investigations and searches for specific treatment modalities in male infertility, more attention should be paid to the epididymis and accessory sex gland function.
TL;DR: Semen that was diluted and stored in the commercially available Tris-based extender (T2) maintained sperm motility for a longer period of time, and acrosome and membrane integrity was higher during storage for up to 30 h as compared to the other extenders independent of storage temperature.
TL;DR: The data show that sperm DD negatively correlates with standard semen parameters and that an isolated abnormality of sperm DD, a marker of sperm DNA integrity, is uncommon in infertile men.