Effects of seminal plasma from cigarette smokers on sperm viability and longevity

Smoking and Male Infertility: An Evidence-Based Review

Many studies have reported that the contents of cigarette smoke negatively affect sperm parameters, seminal plasma, and various other fertility factors. Nevertheless, the actual effect of smoking on male fertility is not clear. The effect of smoking on semen parameters is based on the well-established biological finding that smoking increases the presence of reactive oxygen species, thereby resulting in oxidative stress (OS). OS has devastating effects on sperm parameters, such as viability and morphology, and impairs sperm function, hence reducing male fertility. However, not all studies have come to the same conclusions. This review sheds light upon the arguable association between smoking and male fertility and also assesses the impact of non-smoking routes of tobacco consumption on male infertility. It also highlights the evidence that links smoking with male infertility, including newly emerging genetic and epigenetic data, and discusses the clinical implications thereof.

The hazardous effects of tobacco smoking on male fertility

The substantial harmful effects of tobacco smoking on fertility and reproduction have become apparent but are not generally appreciated. Tobacco smoke contains more than 4000 kinds of constituents, including nicotine, tar, carbonic monoxide, polycyclic aromatic hydrocarbons, and heavy metals. Because of the complexity of tobacco smoke components, the toxicological mechanism is notably complicated. Most studies have reported reduced semen quality, reproductive hormone system dysfunction and impaired spermatogenesis, sperm maturation, and spermatozoa function in smokers compared with nonsmokers. Underlying these effects, elevated oxidative stress, DNA damage, and cell apoptosis may play important roles collaboratively in the overall effect of tobacco smoking on male fertility. In this review, we strive to focus on both the phenotype of and the molecular mechanism underlying these harmful effects, although current studies regarding the mechanism remain insufficient.

Evaluation of Effect of Cigarette Smoking on Vital Seminal Parameters which Influence Fertility

INTRODUCTION

Cigarette smoke contains many compounds which are proven carcinogens having detrimental effect on various organs. The free radicals and other carcinogens have a harmful effect on testicular function which may affect male fertility directly.

AIM

Although many studies have been conducted to establish the relationship between cigarette smoking and male infertility, their conclusions have been highly controversial. This evoked our interest to investigate this intriguing research question.

MATERIALS AND METHODS

One hundred and twenty three subjects were included in the present study amongst which 20 were non smokers, 42 with smoking history of less than 5 years and 61 with more than 5 years.

RESULTS

Cigarette smoking was found to have a detrimental effect on both the sperm motility and the sperm count, but the effect on sperm motility was greater than that of sperm count.

CONCLUSION

This study throws light on the detrimental effect of cigarette smoking on male fertility as reflected by decreased vital parameters of semen like sperm motility and sperm count.

Alteration of sperm protein profile induced by cigarette smoking

Cigarette smoking is associated with lower semen quality, but how cigarette smoking changes the semen quality remains unclear. The aim of this study was to screen the differentially expressed proteins in the sperm of mice with daily exposure to cigarette smoke. The 2D gel electrophoresis (2DE) and mass spectrometry (MS) analyses results showed that the mouse sperm protein profile was altered by cigarette smoking. And 22 of the most abundant proteins that correspond to differentially expressed spots in 2DE gels of the sperm samples were identified. These proteins were classified into different groups based on their functions, such as energy metabolism, reproduction, and structural molecules. Furthermore, the 2DE and MS results of five proteins (Aldoa, ATP5a1, Gpx4, Cs, and Spatc1) were validated by western blot analysis and reverse transcriptase-polymerase chain reaction. Results showed that except Spatc1 the other four proteins showed statistically significant different protein levels between the smoking group and the control group (P < 0.05). The expressions of three genes (Aldoa, Gpx4, and Spatc1) were significantly different (P < 0.05) at transcription level between the smoking group and the control group. In addition, five proteins (Aldoa, ATP5a1, Spatc1, Cs, and Gpx4) in human sperm samples from 30 male smokers and 30 non-smokers were detected by western blot analysis. Two proteins (Aldoa and Cs) that are associated with energy production were found to be significantly altered, suggesting that these proteins may be potential diagnostic markers for evaluation of smoking risk in sperm. Further study of these proteins may provide insight into the pathogenic mechanisms underlying infertility in smoking persons.

Simultaneous vitality and DNA-fragmentation measurement in spermatozoa of smokers and non-smokers

BACKGROUND

Because cigarette smoke is a powerful ROS producer, we hypothesized that the spermatozoa of smokers would be more at risk of having increased DNA fragmentation than spermatozoa of non-smoking men.

METHODS

A cross-sectional study was performed on consenting smokers and non-smokers, consulting in an infertility clinic for routine sperm analysis. The application of a novel TUNEL assay coupled to a vitality marker, LIVE/DEAD®, allowed both DNA fragmentation and viability measurement within spermatozoa of participants to be analyzed by flow cytometry.

RESULTS

The coupled vitality-DNA fragmentation analysis revealed that non-smokers and smokers, respectively presented medians of 3.6% [0.6-36.8] and 3.3% [0.9-9.6] DNA fragmented spermatozoa among the living spermatozoa population (P > 0.05).

CONCLUSION

No deleterious effect of smoking on spermatozoa was found in our study. More studies concerning potential mutagenic capacities of cigarette smoke on spermatozoa are necessary. In addition, the coupled vitality-DNA fragmentation analysis may orient Assisted Reproductive Technology teams when confronted with patients having a high percentage of DNA-fragmented living spermatozoa.

Do cigarette smoking and obesity affect semen abnormality in idiopathic infertile males?

Purpose

This study was conducted to find the relative risk of semen abnormality with respect to smoking history and obesity.

Materials and Methods

Subfertile or infertile men were enrolled in this study from July 2010 to June 2011. All participants provided their cigarette use information, self-reported weight, height, semen analysis, physical examination, and sexually transmitted disease status. None of the enrolled patients had any specific pathological reason for infertility. Semen abnormality was defined as a condition in which one or more parameters did not satisfy the World Health Organization's criteria.

Results

A total of 1,073 male patients were considered for this study. After the application of the inclusion criteria, 193 patients were finally analyzed. These patients were divided into two groups according to semen abnormality: the normal semen group (n=72) and the abnormal semen group (n=121). Baseline characteristics, except age and smoking history, were not significantly different between the two groups. Smoking history and age were risk factors for the semen abnormality of idiopathic infertile male patients.

Conclusions

Smoking and old age were risk factors for semen abnormality. However, obesity did not affect the semen abnormality. Smoking affected semen quality and is therefore expected to play a negative role in conception.

Prevalence of abnormal spermatozoa in tobacco chewing sub-fertile males

AIM

The aim of the following study is to find out the prevalence of abnormal spermatozoa and associated functional parameters in clinical semen samples of sub-fertile males with the tobacco chewing habit.

SETTINGS AND DESIGN

Retrospective study was conducted at infertility unit of a tertiary health care center, in a period of 3 years.

MATERIALS AND METHOD

Semen of 642 males were analyzed; of them 194 men (30.2%) were tobacco chewers and they were grouped according to their intensity of chewing (<10 and ≥ 10 packets/day). Counts, motility, vitality, and morphology of sperms were analyzed.

RESULTS

In tobacco chewers, 66% of subjects were oligozoospermic, 85% asthenozoospermic and 28% teratozoospermic. Sperm counts (odds ratio [OR] =2.2; 95% confidence interval [CI]: 1.5-3.09), motility (OR = 3.2; 95% CI: 2.05-4.9), and normal morphology (OR = 8.4; 95% CI: 4.9-14.6) were significantly affected (P = 0.001) in tobacco chewers than the non-chewing group. Further, in comparison to the intensity of tobacco chewing, patients with the intensive practice of using ≥10 packets/day had a significant effect on sperm morphology (P = 0.003, OR = 2.7; 95% CI = 1.41-5.08) only. Structural defects in head (P = 0.001) and cytoplasmic residues (P = 0.001) were found to be positively correlated with the intensive chewing, but no significant changes were found in anomalies in mid-piece and tail.

CONCLUSION

The adverse impact of tobacco chewing on semen parameters was evident even with mild chewers, but with the intensive chewing practice, phenotypes of sperms, mainly defects in the head and cytoplasmic residue were severely affected.

Does cigarette smoking affect seminal fluid parameters? A comparative study

OBJECTIVE

To study the effect of cigarette smoking on seminal fluid parameters, namely; volume, sperm concentration, and motility, as well as morphology, leukocyte infiltration, among males complaining of infertility.

METHODS

Between August 2010 and July 2011, seminal fluid analysis was done for 1438 males who are partners of couples who visited the infertility clinic at Prince Rashid Ben Al Hassan Hospital (PRH) for infertility. The men who fit the inclusion criteria (n=960) were classified into two groups: group a (non-smokers; n=564) and group B (smokers; n=396), which represents 41.25% of the study group. Seminal fluid was collected using masturbation after 3-5 days of abstinence then analyzed for volume, sperm count, sperm concentration, motility and morphology. In order to analyze whether the number of cigarettes smoked per day has an effect on the spermatogram; the smoking men were divided into two subgroups: the heavy smokers (n=266) and non-heavy smokers (n=130).

RESULTS

A total of 960 adult males were enrolled. Their age ranged between 21 and 76 years, 564 were non-smokers with mean age of 36. 45±6.27 (Mean±SD). Three-hundred-and-ninety-six were smokers with a mean age of 34.35±4.25 (Mean±SD). There was a significant effect of smoking on the motility of sperms and the ratios of abnormality (p<0.005). Concentration appeared not to be affected by smoking. Furthermore, the group of heavy smokers were found to have lower sperm concentrations and a higher percentage of abnormal sperms compared to the non-heavy smokers.

CONCLUSION

Cigarette smoking has a deleterious effect on some of the seminal fluid parameters (motility, morphology and leukocyte count) which in turn may result in male subfertility.

[In search of the surgical sperm cell: do we have to perform a testicular biopsy systematically?]

INTRODUCTION

Testicular biopsies are diagnostic and therapeutic tools involved in male infertility care. However, this surgery is invasive and not systematically successful. We studied the preoperative clinical and hormonal factors allowing to predict the obtaining of sperm cells.

PATIENTS AND METHODS

A retrospective study was conducted on 209 patients who all had a testicular biopsy for procreation medically assisted (PMA). The studied criteria were: the age at the time of the surgery, the male cause of the infertility, the testicular volume, the tobacco smoking exposure, the concentrations of estradiol, FSH, LH, prolactin, and testosterone. The comparison of both groups (successful biopsy versus failed biopsy) was made in bivariate analysis then in multivariate analysis.

RESULTS

The testicular volume average and the cause were the two only factors which had a real influence on the negativity of the biopsy. In it was added in bivariate analysis a statistically significant correlation of the smoking exposure and the FSH with the failed biopsy.

DISCUSSION

The existence of these factors, and their accumulation, was strongly predictive of a failure of the biopsy. However, we found germ cells in patients exposed to the studied factors, letting think that it is systematically necessary to propose the surgery at the risk of a limited profit.

The alteration of protein profile induced by cigarette smoking via oxidative stress in mice epididymis

Smoking is associated with a declining quality of semen. The aim of this study was to screen and investigate the differential expression of proteins extracted from the epididymis of mice exposed daily with cigarette smoke. Using MALDI-TOF-MS analysis, we found that the protein profile of the mouse epididymis was altered by cigarette smoking and identified 27 proteins from the most abundant and differentially expressed spots in the 2-DE gels of epididymal samples. These proteins were classified into groups according to their functions such as energy metabolism, reproduction and structural molecule activity. Through pathway analysis, these proteins were associated with the glutathione metabolism and protein processing in the endoplasmic reticulum. These results showed that the epididymis may experience oxidative stress following cigarette smoke exposure, which was confirmed using immunohistochemistry. We determine that cigarette smoking can induce oxidative stress in the mouse epididymis, which may cause protein profile altering, thereby impairing epididymis function, and leading to a decline in semen quality.

Increase of 210Po levels in human semen fluid after mussel ingestion

Polonium-210 ((210)Po) radioactive concentrations were determined in human semen fluid of vasectomized non-smoker volunteers. The (210)Po levels ranged from 0.10 to 0.39 mBq g(-1) (mean: 0.23 ± 0.08 mBq g(-1)). This value decreased to 0.10 ± 0.02 mBq g(-1) (range from 0.07 to 0.13 mBq g(-1)) after two weeks of a controlled diet, excluding fish and seafood. Then, volunteers ate during a single meal 200 g of the cooked mussel Perna perna L., and (210)Po levels were determined again, during ten days, in semen fluid samples collected every morning. Volunteers continued with the controlled diet and maintained sexual abstinence through the period of the experiment. A 300% increase of (210)Po level was observed the day following mussel consumption, with a later reduction, such that the level returned to near baseline by day 4.

Association between socio-psycho-behavioral factors and male semen quality: systematic review and meta-analyses

OBJECTIVE

To identify the factors associated with male semen quality from many socio-psycho-behavioral factors.

DESIGN

Medline/PubMed, EMBASE, and CNKI were searched to identify relevant publications for systematic review and meta-analysis.

PATIENT(S)

None.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Thirteen socio-psycho-behavioral factors in 57 cross-sectional studies with 29,914 participants from 26 countries/regions were involved in this review. Six factors (age, body mass index [BMI], psychological stress, smoking, alcohol, and coffee consumption) were included in meta-analyses.

RESULT(S)

Smoking can deteriorate all of the sperm parameters of both fertile and infertile men, but it is not risk factor for semen volume in Switzerland and Iran and for sperm density in the United States, Denmark, and Brazil; higher age and alcohol consumption are risk factors for lower semen volume; and psychological stress can lower sperm density and sperm progressive motility and increase abnormal sperm.

CONCLUSION(S)

This review further suggested that higher age, smoking, alcohol consumption, and psychological stress were risk factors for semen quality. These results indicated that health programs focusing on lifestyle and psychological health would be helpful for male reproductive health. Well-designed studies are needed to further identify the role of more socio-psycho-behavioral factors in male semen quality.

Cigarette smoke extract immobilizes human spermatozoa and induces sperm apoptosis

Cigarette smoking by the male partner adversely affects assisted reproductive techniques, suggesting that it may damage sperm chromatin/DNA and consequently embryo development. The effects of graded concentrations of research cigarettes smoke extract (CSE) on motility, mitochondrial membrane potential (MMP), chromatin integrity and apoptosis were evaluated in spermatozoa obtained from 13 healthy, non-smoking men with normal sperm parameters, by flow cytometry. CSE suppressed sperm motility in a concentration- and time-dependent manner and increased the number of spermatozoa with low MMP, the main source of energy for sperm motility. In addition, CSE had a detrimental effect on sperm chromatin condensation and apoptosis. Indeed, it increased the number of spermatozoa with phosphatidylserine externalization, an early apoptotic sign, and fragmented DNA, a late apoptotic sign, in a concentration- and time-dependent manner. These effects of CSE were of similar or even greater magnitude to those obtained following incubation with tumour necrosis factor-alpha, a cytokine known for its negative impact on sperm function, used as positive control. Since transmission of smoking-induced sperm DNA alterations has been found in pre-implantation embryos, and this may predispose offspring to a greater risk of malformations, cancer and genetic diseases, men seeking to father a child are recommended to give up smoking.

Cigarette smoking and the risk of male infertility

In this research we investigated the effect of cigarette smoking on sperm parameters both before and after swim-up. Semen sample provided from fertile smoker (n = 25), fertile nonsmoker (n = 21), infertile smoker (n = 23) and infertile nonsmoker men (n = 32). Semen analysis was performed manually according to the World Health Organization (WHO) standards guidelines. Present research showed that sperm parameters quality in smoker men was approximately lower than nonsmoker men. As well as present research showed that cigarette smoking has dose dependent effect on sperm parameters, but this effect was not significant. Therefore, it appears that cigarette smoking is associated with reduced sperm quality and the risk of idiopathic male infertility in smoker men.

Biology of sperm chromatin structure and relationship to male fertility and embryonic survival

Embryonic mortality in mammals is typically thought to result from 'female factor' infertility. There is growing evidence, however, that the status of sperm chromatin (DNA) at the time of fertilisation can also influence embryonic survival. During the final stages of spermatogenesis (spermiogenesis) a number of unique biochemical, morphological and physiological processes take place that are associated with marked changes in the structure of sperm chromatin. In early stages of spermatogenesis, sperm DNA is associated with histone nucleoproteins and structured into classical nucleosome core particles similar to other somatic cells. As spermiogenesis proceeds, the histone nucleoproteins are replaced by transition proteins which are subsequently replaced by protamines. At the completion of spermiogenesis the chromatin of mature sperm has a toroidal structure that is tightly compacted and resistant to denaturation. The compaction is necessary to protect sperm chromatin during transit through the epididymis and female reproductive tract. Disruption to chromatin remodelling during spermiogenesis results in chromatin that is susceptible to denaturation. Inappropriate chromatin structure has been shown in a number of mammalian species to be related to male infertility, and specifically the failure of embryonic development. A range of techniques are available to assess chromatin status in sperm but arguably the most informative is the sperm chromatin structure assay (SCSA). The SCSA is a flow cytometric assay that uses the metachromatic properties of acridine orange to measure the susceptibility of sperm chromatin to acid-induced denaturation. A relationship has been demonstrated, primarily in men, between the SCSA outcome and the probability of continued embryonic development and the establishment of pregnancy after fertilisation. The contribution of sperm chromatin instability to reproductive wastage in both natural mating and assisted reproduction warrants further investigation as it may prove valuable as a means of decreasing the incidence of embryonic mortality. In this regard, it is possible that 'male factor' infertility may emerge as an even more important component in embryonic development.

Tabac et fertilité chez la femme et l'homme

Cigarette smoking consequences on female and male reproduction have been evaluated for twenty years only and thus poorly spread in the general population. However, several studies have noticed noxious effects of tobacco before and after conception, in both women and men, from smokers gametes to their offspring. This negative impact occurs in spontaneous as well as in assisted reproduction (ART). For women, pregnancy rate is decreased, early spontaneous abortions are increased and ovarian reserve is altered. For men, standard sperm parameters are modified and spermatozoon nuclear quality is compromised. One of the mechanisms involved in those anomalies could be the oxidative stress produced by some cigarette smoking components. The consequences on smokers offspring are hardly evaluated yet: pathologies of the respiratory system, decrease of fecundity and cancers outcomes. In conclusion, it seems obvious that smokers - men as women - have to quit smoking before having a parental project.

The influence of cigarette smoking on human sperm quality and DNA fragmentation

The aim of the present study was to evaluate consequences of cigarette smoking on male gametes. In this prospective study, sperm parameters such as sperm density, motility, viability and normal morphology were measured according to the WHO criteria. In addition to these standard parameters, we analysed the degree of DNA fragmentation in spermatozoa using the TUNEL-assay with flow cytometry detection in 57 non-smokers and 51 smokers seeking for infertility counselling. The smoking intoxication was assessed by questionnaire and measured with the CO-Tester. We show that smokers' spermatozoa have a significantly higher DNA fragmentation than non-smokers (32% versus 25.9%, p<0.01). In contrast there is no significant difference in conventional parameters between smokers and non-smokers. The degree of sperm DNA fragmentation is not significantly correlated with any of the conventional parameters. These findings suggest that cigarette smoking may have deleterious effects on sperm nuclear quality and that sperm DNA fragmentation can therefore be considered as an independent parameter with diagnostic, prognostic, and strategic value in the treatment of infertility.

The effects of L-carnitine on sperm parameters in smoker and non-smoker patients with idiopathic sperm abnormalities

PURPOSE

To determine the effects of L: -carnitine on sperm parameters in patients with idiopathic sperm abnormalities.

METHODS

In an academic reproductive care center, 170 patients including 48 smokers and 122 non-smokers participated in a before-after study. Men were given 1 g of L: -carnitine orally 3 x daily for 3 months. Sperm assessment was done before and after the treatment. Main outcome measures were sperm concentration, motility, and morphology before and after the treatment.

RESULTS

L-Carnitine was effective in improvement of percentile of motile sperms, grade A sperms, and normal-shaped sperms. L-Carnitine significantly improved percentile of motile and grade A sperms in non-smokers. Only the change in the median percentile of normal forms was within the significant range in smokers.

CONCLUSIONS

The results of this study indicate that smoker patients should not be excluded from the treatment with L-carnitine based on smoking alone.

Influence of cigarette smoking on spermatozoa via seminal plasma

Numerous investigations have been conducted on the relationship between cigarette smoking and male infertility, however, the exact molecular mechanisms are not well understood in most of the cases. Few studies have indicated the direct effect of seminal plasma (SP) [in different dilutions with phosphate buffer solution (PBS)] from smokers (SM) on the sperm functional parameters from nonsmokers (non-SM). The aim of this study was to provide evidence that cigarette smoking affects male fertility via altering the sperm quality. Our results indicated that exposure of spermatozoa from the non-SM to the SP from the SM yielded a significant reduction in the sperm motility and acrosome reaction and an elevation in the amount of malondialdehyde (MDA), in a certain time course. Exposure of spermatozoa from the SM to the SP from the non-SM or with PBS resulted in the nonsignificant improvement in the altered sperm functional parameters indicating removal of SM's SP and then subsequent reconstitution with physiological media could be of clinical significance in the various assisted reproductive technologies applied for SM. However, the detrimental effect of SM's SP on non-SM's spermatozoa was prominent. In addition, as spermatozoa in SM's SP are susceptible to peroxidative damages, men with such cells who wish to have children should especially benefit from quitting smoking.

Smoking habits of parents and male: female ratio in spermatozoa and preimplantation embryos

BACKGROUND

Previous observations have addressed a decreased male:female ratio associated with smoking. Our aim was to assess whether this effect is observed at the spermatozoa or at the early embryo development.

METHODS

We retrospectively assessed smoking intake habits of 56 couples included in our preimplantation genetic diagnosis (PGD) program. Three groups were established according to male or female cigarette consumption per day: non-smokers, smokers (1-19 cigarettes per day) and heavy smokers (> or =20 cigarettes per day). Fluorescence in-situ hybridization (FISH) was performed on ejaculated sperm samples to analyse chromosomes X and Y. On day 3, embryos were also analysed. Additionally, sperm samples from four heavy smoking and four non-smoking donors were prospectively analysed before and after capacitation.

RESULTS

FISH on spermatozoa revealed no statistical differences in the Y:X ratio between the three groups. However, in the PGD study, in male heavy smokers, the XY:XX embryo ratio was decreased compared with non-smokers (22:47 versus 80:71; P = 0.0057). The smoking condition of the female partner had no significant effect on embryo XY:XX ratio, but for non-smoking females with a heavy smoking partner, the ratio was decreased (P = 0.0018) compared with non-smoking males. In heavy smoking donors a decreased of Y:X ratio was observed after swim-up with a statistically significant difference of ratios (P = 0.021).

CONCLUSIONS

Smoking habits of males do not have an effect on the percentage of X- and Y-bearing spermatozoa on ejaculated samples. However, male heavy smokers produce an increased incidence of female embryos that could be related to an enrichment of X spermatozoa after swim-up in patients with high tobacco consumption.

Mini-review of studies on the effect of smoking and drinking habits on semen parameters

This article aims at evaluating the impact of cigarette smoking and alcohol consumption on different semen parameters (volume, concentration, motility, morphology, total sperm count and viability), by reviewing all the published literature on smoking, alcohol and sperm morphology. The studies on smoking and sperm abnormalities show a limited effect of smoking on conventional sperm parameters. The data on alcohol are more sparse, and show an apparent protective effect of moderate alcohol drinking on sperm parameters, probably due to the antioxidant effect of some alcoholic beverages. Unfortunately, none of the studies that considered both alcohol and smoking habits conducted the analysis of the joint effect of the two exposure factors. More standardized laboratory assays and increased sample size studies involving subjects with various level of exposure to alcohol and smoking are needed to better establish the role of these factors in male infertility.

Effects of cigarette smoking on sperm plasma membrane integrity and DNA fragmentation

Cigarette smoking is a serious health problem of our society. It is known that cigarette smoke is a cell mutagen and carcinogen, and that it may affect adversely male fertility. The possible detrimental effects on sperm cells are of great interest but the data available to support this statement are somewhat elusive. To approach this problem we examined conventional semen parameters, plasma membrane translocation of phosphatidylserine (PS) (annexin V/6-CFDA cell staining) and sperm DNA integrity (comet assay) in a group of healthy man smoking cigarettes on a regular basis. The results of the study were compared with the results of the same tests in healthy non-smoking donors. Significant difference in standard sperm parameters between the two groups was not found. Intensive expression of PS on the sperm plasma membrane surface (assayed by annexin V positive staining) was detected in the smokers group. There is a significant increase of population of apoptotic spermatozoa in ejaculates of smokers. Albeit DNA damages (high frequencies of double- and single- stranded DNA breaks) in spermatozoa of smokers are increased compared with non-smokers, but this difference is not statistically significant. Sperm DNA integrity of healthy smokers remains in the normal range, but a clear negative trend is observed, especially in respect of disturbance of plasma membrane phospholipid asymmetry.

Impact négatif du tabac sur la fertilité masculine : des spermatozoïdes à la descendance

Cigarette smoking has negative effects on male fertility. Recent studies showed an active transfer of several components of cigarettes through the blood-testis barrier. The presence of these components in the seminal plasma may induce a degradation of sperm parameters and nuclear quality of spermatozoa, and compromise the chances of pregnancy. Moreover, smoking may have a negative impact on the smokers'offspring: poor quality embryos, development of childhood cancers. Oxidative stress-induced DNA damage seems to be one of the major causes of sperm quality alteration. Several methods are now available to analyze the degree of DNA fragmentation. In order to optimize the success rate of assisted reproduction technologies, the deleterious effects of smoking on male fertility and the necessity of cessation have to be explained in detail to these patients.

Male smokers have a decreased success rate for in vitro fertilization and intracytoplasmic sperm injection

OBJECTIVE

Smoking by one or both partners can adversely affect IVF outcome. We investigated whether smoking may also play a role in the success rate of intracytoplasmic sperm injection (ICSI), in which initial steps of fertilization are bypassed.

DESIGN

Three hundred one couples (ICSI: 153, IVF: 148) participated in 415 treatment cycles (ICSI: 202, IVF: 213). One hundred thirty-nine men were habitual smokers (ICSI: 71, IVF: 68). Seventy-seven women were smokers (ICSI: 41, IVF: 36). Multiple nominal regression analyses of various steps of assisted reproduction included smoking status, age, semen parameters, and number of embryos transferred.

SETTINGS

Reproductive and andrology unit of the university.

PATIENT(S)

Three hundred one couples seeking fertility treatment.

INTERVENTION(S)

Assisted reproduction by in vitro fertilization (IVF) or ICSI.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy.

RESULT(S)

Intracytoplasmic sperm injection success (clinical pregnancy) in women with smoking male partners was 22% and was 38% with nonsmoking partners. Similar results were seen for IVF, with 18% vs. 32%. Multinominal logistic regression analysis revealed smoking in men to be a significant predictor of ICSI outcome, along with female age and the number of embryos transferred, whereas clinical pregnancies after IVF were dependent on smoking in men, number of embryos transferred, sperm motility, and female age. Female smoking influenced the number of oocytes retrieved and the fertilization rate of oocytes in IVF but not in ICSI. The odds ratio for failure of ICSI for male smokers in comparison to male nonsmokers was 2.95 (IVF: 2.65).

CONCLUSION(S)

Smoking by males decreases the success rates of assisted reproduction procedures, not only in IVF, but also in ICSI. Apart from putative adverse effects during fertilization, altered DNA in spermatozoa might hamper development of the embryo.

Semen quality of male smokers and nonsmokers in infertile couples

OBJECTIVE

To investigate the effect of cigarette smoking on main sperm variables.

DESIGN

Cohort study.

SETTING

Men attending the andrology laboratory in the context of infertility investigation in the couple.

PATIENT(S)

Eight hundred thirty-nine smokers and 1,266 non-smokers were enrolled; 655 smokers and 1,131 nonsmokers fulfilled the inclusion criteria and were compared. Standard clinical analysis of semen.

RESULT(S)

Cigarette smoking was associated with a significant decrease in sperm density (-15.3%), total sperm count (-17.5%), total number of motile sperm (-16.6%), and citrate concentration (-22.4%). The percentage of normal forms was significantly reduced in smokers, and sperm vitality, ejaculate volume, and fructose concentration were slightly but nonsignificantly affected.

CONCLUSION(S)

Cigarette smoking is associated with reduced semen quality.

Effect of cigarette smoking on levels of seminal oxidative stress in infertile men: a prospective study

OBJECTIVE

To investigate levels of seminal oxidative stress (OS) and sperm quality in a group of infertile men with a history of cigarette smoking.

DESIGN

A prospective clinical study.

SETTING

Male infertility clinic, Urological Institute, the Cleveland Clinic Foundation, Cleveland, Ohio.

PATIENT(S)

Infertile men who smoked cigarettes (n = 20), infertile men who were nonsmokers (n = 32), and healthy nonsmoking donors (n = 13).

INTERVENTION(S)

Genital examination, standard semen analysis, sperm DNA damage.

MAIN OUTCOME MEASURE(S)

Levels of seminal reactive oxygen species (ROS) and total antioxidant capacity (TAC) measured by a chemiluminescence assay and seminal OS assessed by calculating a ROS-TAC score. Sperm DNA damage was measured by sperm chromatin structure assay.

RESULT(S)

Smoking was associated with a 48% increase in seminal leukocyte concentrations (P<.0001), a 107% increase in ROS levels (P=.001), and a 10-point decrease in ROS-TAC scores (P=.003). Differences in standard sperm variables and DNA damage indices between the infertile smokers and infertile nonsmokers were not statistically significant.

CONCLUSION(S)

Infertile men who smoke cigarettes have higher levels of seminal OS than infertile nonsmokers. Given the potential adverse effects of seminal OS on fertility, physicians should advise infertile men who smoke cigarettes to quit.

Evaluation of the effect of a cervical cap device on sperm functional characteristics in vitro

Intracervical insemination continues to be employed for homologous and donor insemination in natural and stimulated cycles. Efficacy studies for potential fertility involve in vivo assessment; however, in vitro testing of particular sperm function(s) critically involved in fertilization is an important component of such evaluation. We report here on the in vitro evaluation of the effects of the silicone Veos cervical cap (Veos, London, UK) on sperm function. Donor semen was exposed to the Veos cervical cap or a sterile 15-cc centrifuge tube (control), or treated with the spermicide nonoxynol-9 (5 mg x ml(-1) in saline) for 4 h at 37 degrees C and 5% CO2 in water-saturated air. After exposure, motility characteristics, both in semen and in spermatozoa processed by standard swim-up procedure, cervical mucus penetration and sperm-zona pellucida interaction using the hemizona assay were assessed. Results indicated that exposure to the Veos cervical cap had no effect on either sperm motility characteristics or sperm-zona pellucida interaction. A small but significant difference was observed for cervical mucus penetration (P = 0.05); however, for both the control and treated groups, vanguard spermatozoa exceeded manufacturer's guidelines for a normal test, a penetration distance of > or = 30 mm. As expected, nonoxynol-9 was a potent inhibitor of sperm function. Lack of adverse effects on in vitro spermatozoa functional characteristics after exposure to the silicone Veos cervical cap supports its addition to the repertoire of fertility treatment modalities when cervical insemination is indicated.

Delayed conception and active and passive smoking. The Avon Longitudinal Study of Pregnancy and Childhood Study Team

OBJECTIVE

To determine whether passive as well as active smoking by women or smoking by men is associated with delayed conception, after adjustment for confounding factors.

DESIGN

Population study of couples expecting a baby. Logistic regression was performed to identify factors associated with delayed conception.

SETTING

The Avon Health Authority area, United Kingdom.

PATIENT(S)

All couples expected to deliver between April 1991 and December 1992.

INTERVENTION(S)

Questionnaires administered early in pregnancy.

MAIN OUTCOME MEASURE(S)

Time taken to conceive, categorized as <6 months, 6-11 months, 1-3 years, and >3 years.

RESULT(S)

After correction for confounding factors, delayed conception was statistically significantly associated with both active smoking by the woman (odds ratio [OR] 1.23 [95% CI 0.98-1.49] for > 6 months and 1.54 [95% CI 1.19-2.01] for >12 months) and her exposure to passive smoking (OR 1.17 [95% CI 1.02-1.37] and 1.14 [95% CI 0.92-1.42]) compared with women with no exposure to tobacco smoke (referent). Heavy smoking by men was independently associated with delayed conception. In active smokers, the effect increased with the number of cigarettes.

CONCLUSION(S)

Smoking by men and passive and active smoking by women are associated with delayed conception.

Lack of association between smoking and DNA fragmentation in the spermatozoa of normal men

Male factor infertility patients can have anomalies in their sperm nuclei, displaying high levels of loosely packaged chromatin and damaged DNA. The primary objectives of this study were to compare the extent of DNA fragmentation in the spermatozoa of healthy light and heavy smokers versus non-smokers, and to investigate its correlation with concentrations of the smoking markers cotinine and cadmium. A secondary objective was to compare the concentrations of blood cadmium and serum cotinine with corresponding concentrations in seminal plasma. Ninety-seven healthy male volunteers were divided into three groups: non-smokers, light and heavy smokers. There was no difference between the three groups with respect to age, number of ejaculations per week, serum testosterone concentration, and parameters of semen analysis. The percentages of DNA fragmentation in spermatozoa were not statistically different in the heavy smokers (12.11%), light smokers (11.66%) and non-smokers (20.41%). Serum and seminal plasma concentrations of cotinine were significantly higher in heavy smokers compared with the other groups (P < 0.0001). Median values for blood cadmium concentration were higher in heavy smokers (4.50 microg/l) than in light smokers (0.20 microg/l) and non-smokers (0.20 microg/l) (P < 0.001). Cadmium concentration in seminal plasma was significantly higher in heavy smokers (0.20 microg/l) than in light smokers (0.10 microg/l) and non-smokers (0. 10 microg/l) (P < 0.05). In summary, our results indicate no association between smoking and DNA fragmentation in the spermatozoa of healthy men.