The association of age and semen quality in healthy men

BACKGROUND: Although the effect of maternal age on fertility is well known, it is unclear whether paternal age also affects fertility. This cross-sectional study sought to characterize the association between age and semen quality, a well-known proxy of fertility status. METHODS: A convenience sample of 97 non-smoking men (aged 22-80 years) without known fertility problems was recruited from a national government laboratory. The men provided semen samples and information relating to lifestyle, diet, medical and occupational details. Semen volume (ml), sperm concentration (x10(6)/ml), total sperm count (x10(6)), motility (%), progressive motility (%) and total progressively motile sperm count (x10(6)) were measured. RESULTS: After adjusting for covariates, semen volume decreased by 0.03 ml per year of age (95% CI: -0.05, -0.01); motility decreased by 0.7% per year (95% CI: -0.92, -0.43); progressive motility decreased by 3.1% per year (95% CI: -4.5, -1.6); and total progressively motile sperm count decreased by 4.7% per year (95% CI: -7.2, -2.2). There was a suggested decrease in sperm concentration and count. The proportion of men with abnormal volume, concentration and motility was significantly increased across the age decades. CONCLUSIONS: In a convenience sample of healthy men from a non-clinical setting, semen volume and sperm motility decreased continuously between 22-80 years of age, with no evidence of a threshold.     

Dietary intake of antioxidant nutrients is associated with semen quality in young university students

STUDY QUESTION What are the associations between the dietary intake of antioxidant nutrients and semen parameters in young men? SUMMARY ANSWER Our study suggests that some sperm parameters are sensitive to dietary intake of antioxidant nutrients. WHAT IS KNOWN ALREADY A few reports have suggested that some dietary factors might be related to semen quality. However, the relationship between the intake of antioxidant nutrients and semen quality in young men remains unexplored. STUDY DESIGN, SIZE, DURATION In this cross-sectional study, 215 young men were included between October 2010 and November 2011. PARTICIPANTS/MATERIALS, SETTING, METHODS Healthy university students with complete dietary and semen quality data were analyzed. Dietary intake was recorded using a validated food frequency questionnaire. The associations between the energy-adjusted nutrient intake of antioxidants in quartiles and the semen volume, sperm concentration, sperm motility, sperm morphology, total sperm count and total motile sperm count were assessed using multivariate linear regression. MAIN RESULTS AND THE ROLE OF CHANCE Out of 240 students who contacted us, 223 (92.9%) were eligible to participate in this study, and 215 attended the clinical appointment. In the multivariate adjusted linear regression models, there was a positive association between dietary intakes of cryptoxanthin (P(trend) = 0.03), vitamin C (P(trend) = 0.04), lycopene (P(trend) = 0.03) and β-carotene (P(trend) = 0.04) and total motile sperm count. The semen volume increased with higher intakes of vitamin C (P(trend) = 0.04). LIMITATIONS, REASONS FOR CAUTION Only one sample of semen was taken for each subject. However, there are indications that one semen sample may be sufficient to characterize the semen quality of the individuals in epidemiological studies. Bias due to measurement errors may also occur since there is no perfect method to assess diet. However, any bias due to measurement error would be non-differential and would reduce, not increase, the strength of the associations. Although selection bias in cross-sectional studies might not always be ruled out, our subjects were university student volunteers who were rewarded for their participation and the study was not advertised as a fertility study. WIDER IMPLICATIONS OF THE FINDINGS Previous articles in this area have focused mainly on men attending fertility clinics, thus our study brings generalizability to young men of the general population with unknown or untested fertility. Some of our results are in agreement with the previously reported papers. STUDY FUNDING/COMPETING INTEREST(S) This study was supported by 'Fundación Séneca, Región de Murcia, Agencia Regional de Ciencia y Tecnología, grant number: 08808/PI/08', and 'Ministerio de Ciencia e Innovación, Instituto de Salud Carlos III (FIS) grant number: PI10/00985'. The authors have no competing interests to declare.     

Antioxidant treatment of patients with asthenozoospermia or moderate oligoasthenozoospermia with high-dose vitamin C and vitamin E: a randomized, placebo-controlled, double-blind study

In a randomized, placebo-controlled, double-blind study we investigated whether high-dose oral treatment with vitamins C and E for 56 days was able to improve semen parameters of infertile men. Ejaculate parameters included semen volume, sperm concentration and motility, and sperm count and viability. Thirty-one patients without genital infection but with asthenozoospermia (< 50% motile spermatozoa) and normal or only moderately reduced sperm concentration (> 7 x 10(6) spermatozoa/ml) (according to WHO criteria) were examined. To investigate the influence of the epididymal storage period on semen parameters, the patients were asked to deliver two semen samples with abstinence times of 2 and 7 days both before and at the end of vitamin treatment. After randomization, the patients received either 1000 mg vitamin C and 800 mg vitamin E (n = 15) or identical placebo capsules (n = 16). No changes in semen parameters were observed during treatment, and no pregnancies were initiated during the treatment period. Combined high-dose antioxidative treatment with vitamins C and E did not improve conventional semen parameters or the 24-h sperm survival rate. Prolonged abstinence time increased ejaculate volume (P < 0.05), sperm count (P < 0.05), sperm concentration (P < 0.05) and the total number of motile spermatozoa (P < 0.05).     

Increased levels of sperm ubiquitin correlate with semen quality in men from an andrology laboratory clinic population

BACKGROUND: Ubiquitin, a house-keeping protein that marks other proteins for proteasomal degradation, tags defective sperm during epididymal passage. To establish ubiquitin as a biomarker of human infertility, the present study examines the relationships between sperm ubiquitin content and clinical semen parameters among men from an infertility clinic population with varied aetiologies. METHODS: Anti-ubiquitin immunoreactivity was measured by flow cytometric sperm-ubiquitin tag immunoassay (SUTI) in sperm samples of 28 infertility patients and 15 fertile donors. Semen analyses were performed by computer-assisted semen analysis and World Health Organization morphology. RESULTS: Median values of ubiquitin-induced fluorescence had a strong negative correlation with sperm count (r = -0.63, P = 0.0003) and a positive correlation with % abnormal morphology (r = 0.55, P = 0.01). Infertility patients (n = 28) had significantly higher levels of sperm ubiquitin. Out of 28 patients, six reported possible occupational exposures to solvents, three were current smokers and six were ex-smokers. Within the patient group, men with known male factor infertility, those with self-reported occupational exposure to solvents and current smokers had the highest sperm ubiquitin levels. When men with jobs involving potential occupational exposure to solvents were combined with current smokers, the highest correlations were found between sperm ubiquitin and motility (r = -0.74), count (r = -0.82) and % sperm abnormalities (r = 0.73). CONCLUSIONS: Increased sperm ubiquitin was inversely associated with sperm count, motility and % normal morphology, supporting the use of ubiquitin as a biomarker of human semen quality. SUTI assay confirmed poor semen quality in all men with poor clinical semen parameters, but also was high in some patients with seemingly good clinical semen parameters. Occupational exposure to solvents and smoking may have contributed to high levels of sperm ubiquitin in some of these patients.     

Quantitative effects of male age on sperm motion

BACKGROUND: Semen quality is associated with fertility status, but there is little quantitative information on risk factors that affect semen quality, especially in non-clinical populations. Advancing male age has been associated with a decline in semen quality, with the largest effect being on sperm motility. However, there is little quantitative data on the specific components of sperm motion that are affected by male age. METHODS: We performed linear regression analyses of 14 aspects of semen quality measured by computer-assisted semen analysis (CASA) in a non-clinical cohort of 90 non-smoking men, aged 22-80 years, who had no history of infertility or reproductive problems. RESULTS: We found age-associated declines in CASA-determined motility (% motile, 0.8% per year; % progressively motile, 0.9% per year; % rapidly motile, 0.4% per year, P 相似文献   

The association of folate, zinc and antioxidant intake with sperm aneuploidy in healthy non-smoking men

BACKGROUND: Little is known about the effect of paternal nutrition on aneuploidyin sperm. We investigated the association of normal dietaryand supplement intake of folate, zinc and antioxidants (vitaminC, vitamin E and β-carotene) with the frequency of aneuploidyin human sperm. METHODS: Sperm samples from 89 healthy, non-smoking men from a non-clinicalsetting were analysed for aneuploidy using fluorescent in situhybridization with probes for chromosomes X, Y and 21. Dailytotal intake (diet and supplements) for zinc, folate, vitaminC, vitamin E and β-carotene was derived from a food frequencyquestionnaire. Potential confounders were obtained from a self-administeredquestionnaire. RESULTS: After adjusting for covariates, men with high folate intake(>75th percentile) had lower frequencies of sperm with disomiesX, 21, sex nullisomy, and a lower aggregate measure of spermaneuploidy (P 0.04) compared with men with lower intake. Inadjusted continuous analyses, total folate intake was inverselyassociated with aggregate sperm aneuploidy (–3.6% change/100µg folate; 95% CI: –6.3, –0. 8) and resultswere similar for disomies X, 21 and sex nullisomy. No consistentassociations were found between antioxidant or zinc intakesand sperm aneuploidy. CONCLUSIONS: Men with high folate intake had lower overall frequencies ofseveral types of aneuploid sperm.     

Traffic pollutants affect fertility in men

BACKGROUND: Given the lack of consensus about the effect of traffic-derived pollutants on male fertility, we evaluated semen quality in men occupationally exposed to traffic. METHODS: Semen quality was investigated in 85 men employed at motorway tollgates and in 85 age-matched men living in the same area. Semen, circulating sex hormones, methaemoglobin, sulphaemoglobin, carboxyhaemoglobin, lead (Pb) and zinc (Zn) protoporphyrin were assayed. Environmental carbonium oxide, nitrogen oxide, sulphur oxide and Pb were also measured. RESULTS: Sperm count, and serum levels of FSH, LH and testosterone were within normal range in both groups. Total motility, forward progression, functional tests and sperm kinetics were significantly lower in tollgate workers versus controls. In a subset of tollgate workers with motility below normal, methaemoglobin was inversely correlated with total motility, viability, the hypo-osmotic swelling test, the acridine orange test, the cervical mucus penetration test, linearity, and amplitude of lateral movement of the sperm head, whereas blood levels of Pb were inversely correlated with viability and sperm count. CONCLUSIONS: The finding that blood methaemoglobin and Pb were inversely correlated with sperm parameters indicates that nitrogen oxide and Pb adversely affect semen quality.     

Follow-up of sperm concentration and motility in patients with lymphoma

Lymphomas are a group of diseases, prevalent at reproductive age. Fertility is notoriously reduced among lymphoma patients. This study evaluates pre- and post-treatment semen concentration and motility, and factors associated with semen quality deterioration. We followed-up 33 patients with non-Hodgkin's lymphoma or with Hodgkin's disease during the years 1987-1997 who were referred for semen cryopreservation. Pretreatment semen analysis, and hormonal profile were recorded at diagnosis and at least 1 year after completion of the treatment, and compared. Medical records for disease type, disease stage and treatment protocols were related to long-term sperm outcome. Hormonal concentrations were not predictive of post-treatment sperm concentration. In patients with localized disease, initial sperm concentration and motility tended to be preserved, compared with patients with widespread disease (P: = 0. 016). In Hodgkin's disease patients, treatment with the adriamycin, bleomycin, vinblastine and dacarbazine (ABVD) protocol was superior to the mechloretamine, vincristine, procarbazine and prednisone with ABV protocol regarding germinal toxicity (P: = 0.0008). The post-treatment sperm outcome was better in patients treated with local irradiation than in those who did not undergo irradiation (P: = 0.0027). No predictive tools for post-treatment fertility were found and, therefore, every patient with a lymphoma should have his semen cryopreserved at diagnosis.     

Comparison between the first and the second electroejaculate qualities obtained from neurologically intact men suffering from anejaculation

BACKGROUND: Electroejaculation is an artificial method used to procure semen from neurologically intact men suffering from anejaculation that have failed other treatments. In order to establish the consistency of semen parameters in repeated electroejaculations, we compared retrospectively the quality of the first and the second electroejaculates of anejaculatory men who were not suffering from any known neurological problems. METHODS: Between 1995 and 2004, 59 neurologically intact men suffering from anejaculation underwent multiple electroejaculations. Sperm quality of the first and the second ejaculates was compared. RESULTS: A significant difference of 0.33 +/- 0.16 ml in the volume of the antegrade portion was found (P = 0.023). The results showed no significant difference in the concentration, motility, count and total motile count of the antegrade ejaculates. In retrograde ejaculates there were no significant differences in the count, motility and total motile count. Neither was there any difference in the total count and the total motile count of both fractions. CONCLUSIONS: Electroejaculation is a reliable method for semen procurement in men suffering from anejaculation. Since semen parameters are consistent, repeated procedures are not justified for improving the sperm quality in anejaculatory, neurologically intact men.     

Detection of fractalkine in human seminal plasma and its role in infertile patients

BACKGROUND: Fractalkine is a relatively newly discovered CX(3)C chemokine, which is a chemoattractant for T cells, monocytes and natural killer cells. Several reports have demonstrated the association between chemokine levels in seminal plasma and semen quality. The fractalkine levels in ejaculates from normal donors and infertile male patients with or without asthenozoospermia, were examined and correlated with sperm motility and morphology. METHODS AND RESULTS: Western blot analysis showed fractalkine protein to be present in the seminal plasma. Fractalkine titres in the seminal plasma of infertile men with asthenozoospermia (0.64 +/- 0.04 microg/ml; n = 58) were lower than those in patients without asthenozoospermia (0.94 +/- 0.10 microg/ml; n = 22, P < 0.01) and fertile donors (1.04 +/- 0.07 microg/ml; n = 10, P < 0.001). There was no significant difference between fractalkine levels in patients with and without leukospermia. No significant correlation was found between fractalkine and interleukin-8 levels in seminal plasma. Sperm motility was positively correlated (R(2) = 0.14, P < 0.001) with fractalkine concentration. The existence of CX(3)CR-positive leukocytes in semen was confirmed using specific primers for CX(3)CR. CONCLUSIONS: These results suggest that fractalkine is a chemokine associated with sperm motility and the migration of CX(3)CR-positive leukocytes into semen.     

Comparison of semen quality obtained by electroejaculation and spontaneous ejaculation in men suffering from ejaculation disorder

BACKGROUND: Electroejaculation has become an accepted form of semen procurement in men suffering from anejaculation. However, sperm in these ejaculates often exhibit low motility. The aetiology of asthenozoospermia remains uncertain. It may be related to primary low-grade motility of sperm from anejaculatory men or to detrimental effects of the electroejaculation process itself. The aim of this study was to determine whether the procedure of electroejaculation alters the quality of the semen by comparing the characteristics of the electroejaculates with those of the normal ejaculates of the same patients. METHODS: Nine men suffering from ejaculation disorders underwent 14 procedures of electroejaculation. The sperm concentration and motility of the 14 samples from electroejaculation were compared with 20 collected at a later date after successful ejaculation by the same patients. RESULTS: The mean +/- SD concentration of the electroejaculates was (52.3 +/- 42.1)x10(6)/ml and of the natural samples (67.4 +/- 38.1)x10(6)/ml. No statistical difference was found between the two groups. The mean percentage of sperm showing progressive motility following electroejaculation was 23.1 +/- 18.8% and 36.3 +/- 16.7% after spontaneous ejaculation. No statistical difference was found between the groups (P = 0.082). Likewise, the quality of sperm motility was similar after both methods of procurement. CONCLUSIONS: In our small-sized study group (nine men with ejaculation disorders), the concentration and the motility of sperm obtained by electroejaculation were not significantly different from sperm obtained naturally.     

Longitudinal changes in semen parameters in young Danish men from the Copenhagen area

BACKGROUND: Several recent studies have reported low sperm concentration in young men recruited from the general population, but it is unknown whether the semen quality of these young men reflects that of more mature men or is reduced due to relative immaturity. We conducted a longitudinal follow-up study to address this question. METHODS: We followed 158 young men (median age = 19.1 years at entry) for up to 4 years and requested quarterly semen samples (total 1838 semen samples) and yearly genital examinations. We examined longitudinal changes in sperm concentration, semen volume, percentage of immotile sperm and percentage of morphologically normal sperm. We used general linear models in which each man served as his own control which also controlled for age, smoking, urogenital infections or disorders, fever and abstinence time. RESULTS: We found no evidence that sperm concentration, total sperm count or percentage of morphologically normal sperm changed appreciably during the 4 years of follow-up. Semen volume appeared to increase slightly with age, perhaps due to greater acceptance of the study protocol by participants. Sperm motility also improved somewhat, although this may, at least in part, reflect a trend in motility measurement. CONCLUSIONS: In this analysis of 1838 semen samples from 158 young men from the Copenhagen area, sperm concentration, total sperm count and sperm morphology did not change significantly during 4 years of follow-up, suggesting that previously reported low sperm concentration and poor sperm morphology among young Danish men are unlikely to be the result of immaturity.     

Semen quality in a residential, geographic and age representative sample of healthy Chinese men

BACKGROUND: Population-based study of semen quality is rare in literature. METHODS: Healthy men aged 20-60 years from six Chinese provinces were invited to participate in the study between December 2000 and November 2002. Posters were distributed in the participating counties to enroll 200 subjects from each province. Medians, percentiles, and proportions below lower threshold of the WHO criteria for semen parameters were calculated. Generalized linear models were used to examine the determinants of semen quality. RESULTS: Semen samples from 1191 healthy Chinese men were collected and analysed. The medians (5th and 95th percentiles) were 2.3 ml (1.0-4.5) for semen volume, 65 x 10(6)/ml (20-150) for semen concentration, 154 x 10(6)/ejection (29-421) for sperm count, 19% (5-32) for rapid progressive motility, 46% (29-66) for progressive motility, 67% (47-81) for total motile spermatozoa, 70% (48-88) for sperm viability and 39% (23-76) for normal morphology. Many healthy Chinese men had semen parameter values below the lower threshold of the WHO criteria. Region, age, abstinence duration and season were important determinants of semen quality. CONCLUSIONS: Chinese men have lower values of semen parameters according to WHO standard, and a lower threshold for normal semen parameters for Chinese men should be considered.     

The effect of intracytoplasmic sperm injection and semen parameters on blastocyst development in vitro

The present study compares the development and quality of blastocysts derived from conventional oocyte insemination with those derived from intracytoplasmic sperm injection (ICSI). Oocytes were collected from patients undergoing ovarian stimulation with human menopausal gonadotrophins for IVF. Patients with normal semen were assigned to conventional oocyte insemination while those with progressive motility <20% and/or normal sperm morphology < or =4% were assigned to ICSI. Resulting embryos were cultured for up to 6 days. The mean number and percentage of embryos reaching the blastocyst stage and the mean number and percentage of blastocysts of high quality on days 5-6 were assessed for both treatment groups and compared. The influence of paternal factors (sperm concentration, motility, progressive motility, morphology) on blastocyst development and quality were assessed by regression analyses. Significantly more ICSI-derived embryos arrested at the 5- to 8-cell stage (P = 0.024) concomitant with the activation of the paternal genome than those derived from conventional oocyte insemination. Significantly fewer ICSI-derived embryos reached the blastocyst stage on days 5-6 (P<0.001) and significantly fewer ICSI-derived embryos were of high quality (P = 0.002) compared with conventional oocyte insemination. When treatment groups were combined and evaluated by regression analysis, progressive motility and sperm morphology were significantly correlated with diminished blastocyst development and quality (P < 0.05). From these data, we conclude that paternal factors and/or performing ICSI in cases of severe male factor infertility may have a detrimental effect on blastocyst development and their quality.     

Biological variation of seminal parameters in healthy subjects

BACKGROUND: A study was undertaken to assess the components of biological variation of seminal parameters in healthy subjects. METHODS: Twenty donor candidates were included in a 10-week follow-up study. Within- and between-subject biological variation, indices of individuality and heterogeneity, coefficient of reliability, critical differences, analytical goals and the lowest value observed with a <5% probability of having a true value less than the World Health Organization (1999) reference value were estimated for the following seminal parameters: concentration, total motility (WHO grades a + b + c), progressive motility (grades a + b), rapid progressive motility (grade a), sperm morphology and vitality. All analysis was performed by a single technician according to WHO 1999 guidelines for routine semen analysis. Analytical variation was assessed on different types of quality control material (frozen straws, sperm suspension, videotape, and slides) and at different (low, medium, high) quality levels. RESULTS: The analytical variation observed depended on the quality control material used and the level of semen quality. Concentration was the semen parameter with highest within- and between-subject variation, and vitality the lowest. Indices of individuality were all <0.7, and coefficients of reliability were high (0.68-0.84). The critical difference for sequential values significant at P < 0.05 for vitality, progressive motility and morphology (34.4, 49.2 and 58.0% respectively) were lower than for concentration (77.8%). CONCLUSIONS: The study results showed that conventional reference values for seminal parameters have little diagnostic value because of their marked individuality, though seminal parameters can be useful for assessing differences in an individual's serial results, in particular of progressive motility, morphology and vitality.     

Does the potential for selection bias in semen quality studies depend on study design? Experience from a study conducted within an infertility clinic

BACKGROUND: The low participation rates in human semen quality studies raises concern for the potential of differential participation based on semen quality (or a surrogate). To explore the potential for differential participation, we compared semen analysis results from study subjects with those of non-study subjects. METHODS: We obtained semen analysis results from 235 study subjects and retrospectively obtained results from a subset of 235 infertility clinic patients that were not study subjects but met the same eligibility criteria. The study was conducted at the Massachusetts General Hospital Infertility Clinic. All semen samples (study subjects and non-study subjects) were analysed for sperm concentration and motility by computer-aided semen analysis (CASA), and morphology was assessed using strict criteria. Semen analysis parameters for the non-study subjects were compared with the semen analysis results from study subjects. RESULTS: For all semen characteristics (sperm concentration, total sperm count, sperm motility and morphology), there were only marginal (non-significant) differences between study subjects and non-study subjects. CONCLUSIONS: Among men from an infertility clinic, we found no strong evidence of differential participation based on semen quality. This is reassuring since the potential for selection bias is of concern in semen quality studies. However, the potential for selection bias in other study designs remains unclear.     

Physiological roles of semenogelin I and zinc in sperm motility and semen coagulation on ejaculation in humans

At ejaculation, human sperm are considered to be mechanically trapped and become immotile in the semen coagulum by binding to semenogelins (Sgs) from the seminal vesicle and zinc ions from the prostate. However, the physiological combined roles of the protein and heavy metal on sperm motility are unknown. Here, we have first demonstrated that Sg I alone, which does not form the semen coagulum without zinc, is an inhibitor of the motility of intact human sperm at physiological concentration. On the other hand, zinc ions alone had no effect on sperm motility, but confer recovery of sperm motility that has been inhibited by Sg I at a concentration equal to or less than 1 mg/ml. These observations suggest that the roles played by Sg I and zinc on sperm motility are not mechanical but physiological. Quartz crystal microbalance analysis suggests that the sperm extract first bind to Sg I and then zinc ions which subsequently increase the protein accumulation, suggesting that Sgs inhibit sperm motility by directly binding to the sperm surface. Further accumulation of Sg I mediated by zinc ions may entrap the quiescent sperm at semen ejaculation.     

Semen quality before and after gonadotoxic treatment

BACKGROUND: The aim of this study was to analyse the semen quality of patients before and after gonadotoxic therapy. PATIENTS AND METHODS: We evaluated semen quality in 314 patients over a 26 year period. The diagnostic categories were leukaemia (n = 13); lymphoma (n = 128); testicular cancer (n = 102); benign conditions (n = 13); and other malignant neoplasms (n = 58). The degree of azoospermia or oligozoospermia for each disease category was recorded. We then analysed the recovery in semen quality over time for each disease category. RESULTS: The mean patient age was 27.9 years (range 13-65 years). A total of 1115 post-treatment semen samples were analysed from 314 patients. There was a significant reduction in the post-treatment sperm concentration, sperm motility and semen volume compared with pre-treatment levels (P < 0.05) in the entire cohort. However, the sperm movement and motility grade remained unaffected. Patients with testicular carcinoma had the lowest pre-treatment sperm concentrations but also the lowest incidence of azoospermia after cancer treatment. Patients with lymphoma and leukaemia had the highest incidence of post-treatment azoospermia and oligospermia. Patients having the largest reductions in their sperm concentration after treatment required the longest recovery period for spermatogenesis. The diagnostic category was the only significant predictor of post-treatment azoospermia. CONCLUSION: Gonadotoxic treatment results in a significant reduction in sperm quality. The type of cancer or disease, and the pre-treatment sperm concentrations were found to be the most significant factors governing post-treatment semen quality and recovery of spermatogenesis. All categories of patients displayed varying degrees of azoospermia and oligozoospermia, and recovery of gonadal function from these states was not significant. This highlights the importance of ensuring sperm banking before treatment, including for patients with benign conditions. Several factors and associations are discussed further in order to give an insight into the pre- and post-gonadotoxic treatment effects.     

Consistent age-dependent declines in human semen quality: A systematic review and meta-analysis

Reduced fertility typically occurs among women in their late 30s, but increasing evidence indicates that advanced paternal age is associated with changes in reproduction as well. Numerous studies have investigated age-based declines in semen traits, but the impact of paternal age on semen parameter values remains inconclusive. Using data from 90 studies (93,839 subjects), we conducted a systematic review and meta-analysis to quantify the effect of male age on seven ejaculate traits (semen volume, sperm concentration, total sperm count, morphology, total motility, progressive motility and DNA fragmentation). Age-associated declines in semen volume, percentage motility, progressive motility, normal morphology and unfragmented cells were statistically significant and results generally seemed to be robust against confounding factors. Unexpectedly, sperm concentration did not decline with increasing male age, even though we found that sperm concentration declined over time. Our findings indicate that male age needs more recognition as a potential contributor to the negative pregnancy outcomes and reduced offspring health associated with delayed first reproduction. We suggest that greater focus on collection of DNA fragmentation and progressive motility in a clinical setting may lead to better patient outcomes during fertility treatments of aging couples.     

Quantitative study of caspase-3 activity in semen and after swim-up preparation in relation to sperm quality

BACKGROUND: There are no studies relating the apoptotic marker caspase-3 in human sperm to different degrees of abnormal sperm concentration, morphology and rapid progressive motility. METHODS: Semen from 67 males with abnormal semen analyses (n = 61) and normozoospermia (n = 6) were used. In each case, sperm from the neat semen (semen fraction) and after gradient centrifugation and swim-up (swim-up fraction) were incubated with a caspase-3 profluorogenic substrate. Caspase-3 activity was quantified in 119 850 sperm, 67 488 from semen and 52 362 from swim-up fractions. Logistic regression was used to estimate odds ratio (with 99% confidence intervals) for the presence of caspase-3-positive sperm. RESULTS: In semen fractions, no relationship was found between abnormal semen analysis subgroups and sperm caspase-3 activity. On the contrary, a significantly increased number of sperm with caspase-3 activity was found in the swim-up fractions from samples with poor sperm morphology. When analysis was restricted to single semen analysis defects, a significant increase of caspase-3-positive sperm was found in the semen fractions of cases with asthenozoospermia, and in the swim-up fractions of cases with teratozoospermia. CONCLUSIONS: Sperm caspase-3 activity seems to be associated with teratozoospermia and asthenozoospermia, thus suggesting that nuclear, mitochondrial and cytoskeletal abnormalities induce caspase-3 activation during spermiogenesis or sperm maturation.