Showing papers on "Sperm published in 2002"
TL;DR: This work focuses on studies showing that males assess mating status and relative fecundity of females, and reveals that modulation of ejaculate investment by males can sometimes result in sperm limitation for females.
Abstract: Sperm are produced in astronomical numbers compared with eggs, and there is good evidence that sperm competition is the force behind the evolution of many tiny sperm. However, sperm production inevitably has costs. Recent research shows that male ejaculate expenditure is dynamic in both time and space, and that males are sensitive to risks of sperm competition and can vary ejaculate size accordingly. We focus on studies showing that males assess mating status and relative fecundity of females, and reveal that modulation of ejaculate investment by males can sometimes result in sperm limitation for females.
1,097 citations
1,019 citations
TL;DR: A novel, sperm-specific phospholipase C, PLC zeta, that triggers Ca(2+) oscillations in mouse eggs indistinguishable from those at fertilisation is identified and it is consistent with sperm PLCZeta as the molecular trigger for development of a fertilised egg into an embryo.
Abstract: Upon fertilisation by sperm, mammalian eggs are activated by a series of intracellular Ca2+ oscillations that are essential for embryo development. The mechanism by which sperm induces this complex signalling phenomenon is unknown. One proposal is that the sperm introduces an exclusive cytosolic factor into the egg that elicits serial Ca2+ release. The ‘sperm factor’ hypothesis has not been ratified because a sperm-specific protein that generates repetitive Ca2+ transients and egg activation has not been found. We identify a novel, sperm-specific phospholipase C, PLCζ, that triggers Ca2+ oscillations in mouse eggs indistinguishable from those at fertilisation. PLCζ removal from sperm extracts abolishes Ca2+ release in eggs. Moreover, the PLCζ content of a single sperm was sufficient to produce Ca2+ oscillations as well as normal embryo development to blastocyst. Our results are consistent with sperm PLCζ as the molecular trigger for development of a fertilised egg into an embryo.
932 citations
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: Supporting this hypothesis, an unusually high fraction of Acps show signs consistent with their being targets of positive Darwinian selection, and many appear to be secreted peptides or prohormones.
Abstract: During mating, males transfer seminal proteins and peptides, along with sperm, to their mates. In Drosophila melanogaster, seminal proteins made in the male's accessory gland stimulate females' egg production and ovulation, reduce their receptivity to mating, mediate sperm storage, cause part of the survival cost of mating to females, and may protect reproductive tracts or gametes from microbial attack. The physiological functions of these proteins indicate that males provide their mates with molecules that initiate important reproductive responses in females. A new comprehensive EST screen, in conjunction with earlier screens, has identified approximately 90% of the predicted secreted accessory gland proteins (Acps). Most Acps are novel proteins and many appear to be secreted peptides or prohormones. Acps also include modification enzymes such as proteases and their inhibitors, and lipases. An apparent prohormonal Acp, ovulin (Acp26Aa) stimulates ovulation in mated Drosophila females. Another male-derived protein, the large glycoprotein Acp36DE, is needed for sperm storage in the mated female and through this action can also affect sperm precedence, indirectly. A third seminal protein, the protease inhibitor Acp62F, is a candidate for contributing to the survival cost of mating, given its toxicity in ectopic expression assays. That male-derived molecules manipulate females in these ways can result in a molecular conflict between the sexes that can drive the rapid evolution of Acps. Supporting this hypothesis, an unusually high fraction of Acps show signs consistent with their being targets of positive Darwinian selection.
462 citations
TL;DR: Using populations of Drosophila melanogaster selected for divergent sperm length or female sperm-storage organ length, experimentally show that male fertilization success is determined by an interaction between sperm and female morphology.
Abstract: Rapid evolution of reproductive traits has been attributed to sexual selection arising from interaction between the sexes. However, little is known about the nature of selection driving the evolution of interacting sex-specific phenotypes. Using populations of Drosophila melanogaster selected for divergent sperm length or female sperm-storage organ length, we experimentally show that male fertilization success is determined by an interaction between sperm and female morphology. In addition, sperm length evolution occurred as a correlated response to selection on the female reproductive tract. Giant sperm tails are the cellular equivalent of the peacock's tail, having evolved because females evolved reproductive tracts that selectively bias paternity in favor of males with longer sperm.
453 citations
TL;DR: This is the first evidence documenting a relationship between the morphological effects of endocrine disruption and the reproductive capabilities of any wild vertebrate, and the results suggest that mixtures ofendocrine-disrupting substances discharged into the aquatic environment could pose a threat to male reproductive health.
Abstract: Endocrine-disrupting chemicals, known to be present in the environment, have great potential for interfering with reproductive health in wildlife and humans. There is, however, little direct evidence that endocrine disruption has adversely affected fertility in any organism. In freshwater and estuarine fish species, for example, although a widespread incidence of intersex has been reported, it is not yet known if intersexuality influences reproductive success. The purpose of this study was, therefore, to determine gamete quality in wild intersex roach (Rutilus rutilus) by assessing sperm characteristics, fertilization success, and ability to produce viable offspring. The results clearly demonstrate that gamete production is reduced in intersex roach. A significantly lower proportion of moderately or severely feminized fish (17.4% and 33.3%, respectively) were able to release milt compared with normal male fish from contaminated rivers (in which 97.6% of the males were able to release milt), reference male fish (97.7%), or less severely feminized intersex fish (experiment 1: 85.8%, experiment 2: 97%). Intersex fish that did produce milt produced up to 50% less (in terms of volume per gram of testis weight) than did histologically normal male fish. Moreover, sperm motility (percentage of motile sperm and curvilinear velocity) and the ability of sperm to successfully fertilize eggs and produce viable offspring were all reduced in intersex fish compared with normal male fish. Male gamete quality (assessed using sperm motility, sperm density, and fertilization success) was negatively correlated with the degree of feminization in intersex fish (r = -0.603; P < 0.001) and was markedly reduced in severely feminized intersex fish by as much as 50% in terms of motility and 75% in terms of fertilization success when compared with either less severely feminized intersex fish or unaffected male fish. This is the first evidence documenting a relationship between the morphological effects (e.g., intersex) of endocrine disruption and the reproductive capabilities of any wild vertebrate. The results suggest that mixtures of endocrine-disrupting substances discharged into the aquatic environment could pose a threat to male reproductive health.
452 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: Grafting testis tissue from newborn mice, pigs or goats into mouse hosts maintains structural integrity and provides the accessibility that is essential for studying and manipulating the function of testes and for preserving the male germ line.
Abstract: Spermatogenesis is a productive and highly organized process that generates virtually unlimited numbers of sperm during adulthood. Continuous proliferation and differentiation of germ cells occur in a delicate balance with other testicular compartments, especially the supporting Sertoli cells1. Many complex aspects of testis function in humans and large animals have remained elusive because of a lack of suitable in vitro or in vivo models. Germ cell transplantation has produced complete donor-derived spermatogenesis in rodents2,3,4,5,6 but not in other mammalian species7,8,9. Production of sperm in grafted tissue from immature mammalian testes and across species has not yet been accomplished. Here we report the establishment of complete spermatogenesis by grafting testis tissue from newborn mice, pigs or goats into mouse hosts. This approach maintains structural integrity and provides the accessibility that is essential for studying and manipulating the function of testes and for preserving the male germ line. Our results indicate that this approach is applicable to diverse mammalian species.
434 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.
TL;DR: Couples should be informed of the risks of an abnormal result related to sperm quality, and of the risk linked to a prenatal procedure as well as about the relatively benign character of some chromosomal anomalies such as de-novo structural anomalies or sex chromosome anomalies in order to be able to make a choice for prenatal testing, or not.
Abstract: BACKGROUND: Prenatal testing was offered in all pregnancies obtained after ICSI with ejaculated or non-ejaculated sperm as part of the evaluation of the safety of ICSI. METHODS: Between 1990 and 2001, a chorionic villus sampling (CVS) or amniocentesis was offered for multiple or singleton pregnancies respectively during a genetic counselling session for all couples applying for ICSI. ICSI was carried out using ejaculated, epididymal or testicular sperm. RESULTS: In total, 1586 ICSI fetuses obtained after fresh embryo transfer were tested by CVS (n = 698) or by amniocentesis (n = 888). Abnormal fetal karyotypes were found in 47 samples [3.0%; 95% confidence interval (CI) 2.2-3.9%]; 25 anomalies (1.6%; 95% CI 1.0-2.3%) were de novo. These were 10 sex chromosomal anomalies and 15 autosomal anomalies [either numerical (n = 8) or structural (n = 7)], and 22 inherited abnormalities (1.4%; 95% CI 0.9-2.1%) (21 balanced, one unbalanced). In 17/22 inherited cases the chromosomal structural defect was inherited from the father. A significantly higher percentage of 2.1% de-novo prenatal chromosomal anomalies was observed for sperm concentrations of <20 × 10 6 sperm per ml, as compared with 0.24% if the sperm concentration was ≥20 × 10 6 sperm per ml (Fisher's exact test, P = 0.006). No statistical difference in frequency of chromosomal anomalies was observed for lower threshold values of sperm concentration (<1 × 10 6 , <5 × 10 6 , <10 × 10 6 and <15 × 10 6 ). A statistical difference was observed for motility criteria, but not morphology. Three chromosomal anomalies were found prenatally after use of epididymal or testicular sperm in a total of 94 samples; two (of 83 tested) were from patients with obstructive and one (of nine tested) was from a patient with non-obstructive azoospermia. CONCLUSIONS: A significantly higher rate of de-novo chromosomal anomalies (1.6 versus 0.5% in amniocentesis for a mean maternal age of 33.5 years; P < 0.007) was observed in ICSI offspring, relating mainly to a higher number of sex chromosomal anomalies and partly to a higher number of autosomal structural anomalies. This finding was related to sperm concentration and motility. The significantly higher rate of observed inherited anomalies (1.4 versus 0.3-0.4% in prenatal tests in the general population; P< 0.001) was related to a higher rate of constitutional chromosomal anomalies, mainly in the fathers. The hypothesis of a higher risk of post-zygotic events as a consequence of the ICSI procedure leading to a higher proportion of chromosomal mosaicism was not confirmed in this study. Couples should be informed of the risks of an abnormal result related to sperm quality, and of the risk linked to a prenatal procedure as well as about the relatively benign character of some chromosomal anomalies such as de-novo structural anomalies or sex chromosomal anomalies in order to be able to make a choice for prenatal testing, or not.
TL;DR: In this paper, the motile sperm organelle morphology examination (MSOME) was applied to the leftover sperm fraction selected for microinjection in 100 random couples referred for ICSI treatment at 3 major in vitro fertilization centers.
Abstract: The aim of the present prospective study was to determine whether subtle sperm morphological characteristics affect the outcome of intracytoplasmic sperm injection (ICSI), and if so, to identify those that are relevant. For this purpose, we developed a new method, the motile sperm organelle morphology examination (MSOME). The examination is performed in real time using an inverted light microscope equipped with high-power Nomarski optics enhanced by digital imaging to achieve a magnification up to 6300x. MSOME was applied to the leftover sperm fraction selected for microinjection in 100 random couples referred for ICSI treatment at 3 major in vitro fertilization centers. We found that the morphological normalcy of the entire sperm cell, according to MSOME criteria, was positively associated with ICSI fertilization rate (area under the receiver operating characteristics [ROC] curve, 88%) but not with pregnancy outcome. The morphological normalcy of the sperm nucleus, defined by MSOME, was significantly and positively associated with both fertilization rate and pregnancy outcome (areas under the ROC curve, 72% and 74%, respectively). These findings indicate that ICSI-associated pregnancy rate may be affected by subtle morphological malformations of the sperm nucleus, which may remain undetected by the embryologist during the routine selection procedure.
01 Jan 2002
TL;DR: Findings indicate that ICSI-associated pregnancy rate may be affected by subtle morphological malformations of the sperm nucleus, which may remain undetected by the embryologist during the routine selection procedure.
Abstract: The aim of the present prospective study was to de- termine whether subtle sperm morphological characteristics affect the outcome of intracytoplasmic sperm injection (ICSI), and if so, to identify those that are relevant. For this purpose, we developed a new method, the motile sperm organelle morphology examination (MSOME). The examination is performed in real time using an in- verted light microscope equipped with high-power Nomarski optics enhanced by digital imaging to achieve a magnification up to 6300. MSOME was applied to the leftover sperm fraction selected for mi- croinjection in 100 random couples referred for ICSI treatment at 3 major in vitro fertilization centers. We found that the morphological normalcy of the entire sperm cell, according to MSOME criteria, was positively associated with ICSI fertilization rate (area under the re- ceiver operating characteristics (ROC) curve, 88%) but not with preg- nancy outcome. The morphological normalcy of the sperm nucleus, defined by MSOME, was significantly and positively associated with both fertilization rate and pregnancy outcome (areas under the ROC curve, 72% and 74%, respectively). These findings indicate that ICSI-associated pregnancy rate may be affected by subtle morpho- logical malformations of the sperm nucleus, which may remain un- detected by the embryologist during the routine selection procedure.
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.
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.
TL;DR: It is concluded that AKAP4 is a scaffold protein required for the organization and integrity of the fibrous sheath and that effective sperm motility is lost in the absence ofAKAP4 because signal transduction and glycolytic enzymes fail to become associated with the fibrus sheath.
TL;DR: Current evidence from studies of ascidian and mammalian fertilization favors a fusion-mediated mechanism; this is supported by experiments indicating that injection of sperm extracts into eggs causes Ca(2+) release by the same pathway as fertilization.
TL;DR: Therapeutic interventions directed toward the isolation of mature spermatozoa by in vitro separation techniques may benefit infertile men in whom oxidative stress has a significant role, but this approach may be limited by the fact that the prolonged centrifugation involved in these procedures may enhance ROS production by spermatoza.
TL;DR: Recent progress is discussed in elucidating mechanisms which regulate sperm capacitation, which correlates with cholesterol efflux from the sperm plasma membrane, increased membrane fluidity, modulations in intracellular ion concentrations, hyperpolarization of the sperm Plasma membrane and increased protein tyrosine phosphorylation.
TL;DR: Fertilization is the sum of the cellular mechanisms that pass the genome from one generation to the next and initiate development of a new organism and the gamete molecules and molecular interactions with essential roles in these events are gradually being discovered.
Abstract: Fertilization is the sum of the cellular mechanisms that pass the genome from one generation to the next and initiate development of a new organism. A typical, ovulated mammalian egg is enclosed by two layers: an outer layer of approximately 5000 cumulus cells and an inner, thick extracellular matrix, the zona pellucida. To reach the egg plasma membrane, sperm must penetrate both layers in steps requiring sperm motility, sperm surface enzymes, and probably sperm-secreted enzymes. Sperm also bind transiently to the egg zona pellucida and the egg plasma membrane and then fuse. Signaling in the sperm is induced by sperm adhesion to the zona pellucida, and signaling in the egg by gamete fusion. The gamete molecules and molecular interactions with essential roles in these events are gradually being discovered.
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.
TL;DR: A well-documented recognition system occurs between pollen grains and the stigma in sporophytic self-incompatibility, where both receptor kinases in the stigma and their peptide ligands from pollen are now known.
Abstract: ▪ Abstract In flowering plants, pollen grains germinate to form pollen tubes that transport male gametes (sperm cells) to the egg cell in the embryo sac during sexual reproduction. Pollen tube biology is complex, presenting parallels with axon guidance and moving cell systems in animals. Pollen tube cells elongate on an active extracellular matrix in the style, ultimately guided by stylar and embryo sac signals. A well-documented recognition system occurs between pollen grains and the stigma in sporophytic self-incompatibility, where both receptor kinases in the stigma and their peptide ligands from pollen are now known. Complex mechanisms act to precisely target the sperm cells into the embryo sac. These events initiate double fertilization in which the two sperm cells from one pollen tube fuse to produce distinctly different products: one with the egg to produce the zygote and embryo and the other with the central cell to produce the endosperm.
TL;DR: The results together indicate that BSP proteins play an important role in sperm membrane lipid modification events that occur during sperm capacitation.
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.
TL;DR: It is concluded that Spag6 is essential for sperm flagellar motility and that it is important for the maintenance of the structural integrity of mature sperm.
Abstract: Gene targeting was used to create mice lacking sperm-associated antigen 6 (Spag6), the murine orthologue of Chlamydomonas PF16, an axonemal protein containing eight armadillo repeats predicted to be important for flagellar motility and stability of the axoneme central apparatus. Within 8 weeks of birth, approximately 50% of Spag6-deficient animals died with hydrocephalus. Spag6-deficient males surviving to maturity were infertile. Their sperm had marked motility defects and was morphologically abnormal with frequent loss of the sperm head and disorganization of flagellar structures, including loss of the central pair of microtubules and disorganization of the outer dense fibers and fibrous sheath. We conclude that Spag6 is essential for sperm flagellar motility and that it is important for the maintenance of the structural integrity of mature sperm. The occurrence of hydrocephalus in the mutant mice also implicates Spag6 in the motility of ependymal cilia.
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: This approach of 'testicular tissue banking' is a promising technique for the preservation of fertility in prepubertal male oncology patients and Xenogeneic transplantation into immunodeficient mice may provide a system for studying spermatogenic failure in infertile men.
Abstract: BACKGROUND: Fertility protection is an urgent clinical problem for prepubertal male oncology patients who undergo either chemotherapy or radiotherapy. As these patients do not have mature sperm to be frozen, there is as yet no effective method to preserve their fertility. METHODS AND RESULTS: Single pieces of immature mouse (1.51.51.5 mm) or rabbit (2.02.0~3.0 mm) testis were cryopreserved, thawed and transplanted into mouse testes. Histological techniques were used to determine the presence of spermatogenesis, which was restored in both mouse and rabbit testicular pieces, and led to the production of mature sperm after both cryopreservation and syngeneic or xenogeneic transplantation into mouse testes. Using sperm developed in the frozen–thawed transplants, mouse offspring were born after in-vitro microinsemination. Furthermore, rabbit offspring were obtained using rabbit sperm that developed in fresh transplants in a xenogeneic surrogate mouse. CONCLUSIONS: This approach of ‘testicular tissue banking’ is a promising technique for the preservation of fertility in prepubertal male oncology patients. Xenogeneic transplantation into immunodeficient mice may provide a system for studying spermatogenic failure in infertile men.
TL;DR: The results of this study indicate that a significant increase in SCSA-defined DNA damage can be found in sperm from infertile men with normal standard sperm parameters, and sperm DNA damage analysis may reveal a hidden abnormality of sperm DNA in infertiles men classified as idiopathic based on apparently normalstandard sperm parameters.
TL;DR: In humans, PHGPx appears to be indispensable for structural integrity of spermatozoa and to codetermine sperm motility and viability and can be considered a predictive measure for fertilization capacity.
Abstract: The selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) accounts for almost the entire selenium content of mammalian testis. PHGPx is abundantly expressed in spermatids as active peroxidase but is transformed to an oxidatively inactivated protein in mature sperm, where it is a major constituent of the mitochondrial capsule in the midpiece. Male infertility in selenium-deficient animals, which is characterized by impaired sperm motility and morphological midpiece alterations, is considered to result from insufficient PHGPx content. We studied the relationship between sperm PHGPx, measured as rescued activity, and human fertility. Sperm specimens from 75 infertile men and 37 controls were analyzed for fertility-related parameters according to World Health Organization criteria. The PHGPx protein content was estimated after reductive solubilization of the spermatozoa by measuring the rescued PHGPx activity. Rescued PHGPx activity of infertile men ranged significantly below that of controls (93.2 6 60.1 units/mg sperm protein vs. 187.5 6 55.3 units/mg) and was particularly low in oligoasthenozoospermic specimens (61.93 6 45.42 units/mg; P , 0.001 compared with controls and asthenozoospermic samples). Rescued PHGPx activity was correlated positively with viability, morphological integrity, and most profoundly forward motility (r 5 0.35, 0.44, and 0.45, respectively). In isolated motile samples, motility decreased faster with decreasing PHGPx content. In humans, PHGPx appears to be indispensable for structural integrity of spermatozoa and to codetermine sperm motility and viability. Because the content of PHGPx, irrespective of the cause of alteration, is correlated with fertility-related parameters, PHGPx can be considered a predictive measure for fertilization capacity. fertilization, gamete biology, male sexual function, sperm, spermatogenesis