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.     

Effects of alcohol and cigarette consumption on human seminal quality

OBJECTIVE: To evaluate the effects of alcohol or cigarette consumption on seminal parameters in a large population of men attending an andrology laboratory. DESIGN: Analysis of ten years of data (1990-1999). SETTING: Andrology and Reproduction Laboratory (Córdoba, Argentina). PATIENT(S): Patients (3,976) were grouped according to nonsmokers; <==20 cigarettes/day; >20 cigarettes/day; nonalcohol consumers; <==500 mL of wine ( approximately 52 g of ethanol) or equivalent/day; and >500 mL of wine or equivalent/day. Patients who drank alcohol and smoked were also considered. INTERVENTION(S): A questionnaire was voluntarily filled out by patients. It provided data on drug consumption and genitourinary diseases. MAIN OUTCOME MEASURE(S): Seminal volume, sperm concentration, motility, viability, and morphology. RESULTS: No statistical differences in seminal parameters were found between the degrees of alcohol or tobacco consumption; so, independently of the degree of consumption patients were considered as smokers or alcohol consumers. CONCLUSION(S): Alcohol or cigarette consumption did not alter the seminal parameters. Nevertheless, when the patients with these two habits were compared to those without these habits, a significant reduction in seminal volume, sperm concentration, percentage of motile spermatozoa, and a significant increase of the nonmotile viable gametes were detected. The synergic or additive effect of these two toxic habits is discussed.     

Negative impact of cigarette smoking on male fertility: from spermatozoa to the offspring

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.     

A placebo-controlled double-blind randomized trial of the use of combined l-carnitine and l-acetyl-carnitine treatment in men with asthenozoospermia

OBJECTIVE: To determine the efficacy of combined l-carnitine and l-acetyl-carnitine therapy in infertile males with oligo-astheno-teratozoospermia. DESIGN: Placebo-controlled double-blind randomized trial. SETTING: University tertiary referral center. PATIENT(S): Sixty infertile patients (aged 20-40 years) with the following baseline sperm selection criteria: concentration, 10 to 40 x 10(6)/mL; forward motility, <15%; total motility, 10% to 40%; and atypical forms, <80%. Fifty-six patients completed the study. INTERVENTION(S): Patients were submitted to a combined treatment of l-carnitine (2 g/d) and l-acetyl-carnitine (1 g/d) or of placebo; the study design was 2 months' wash-out, 6 months of therapy or of placebo, and 2 months' follow-up. MAIN OUTCOME MEASURE(S): Variation in the semen parameters that were used for patient selection. RESULT(S): Even though increases were seen in all sperm parameters after combined carnitine treatment, the most significant improvement in sperm motility (both forward and total) was present in patients who had lower initial absolute values of motile sperm (<4 x 10(6) forward or <5 x 10(6) total motile spermatozoa per ejaculate). CONCLUSION(S): Combined treatment with l-carnitine and l-acetyl-carnitine in a controlled study of efficacy was effective in increasing sperm motility, especially in groups with lower baseline levels.     

Comparison of sperm counts in two groups of men presenting for infertility investigations 20 years apart

Aims:  To compare sperm counts for two groups of men who had presented for infertility investigations approximately 20 years apart.
Methods:  The study compared results for 309 men tested between 1977 and 1981 with those of 559 men tested between 1997 and 1998 using identical methodology. In order to approximate the normal population, only those men with counts above 5 million/mL were included in the final analysis. Bias, due to repeated testing after an initial abnormal result, was minimized by including only the patient's first test results. In addition, to allow for time-dependent changes in the requirements for semen samples, results were included only if a complete sample was produced by masturbation after 3–5 days abstinence.
Results:  There was a small, but statistically significant drop in ejaculate volume (3.9–3.6 mL, P  = 0.015) and a significant increase in the patient's mean age (32.18 vs 35.08, P  < 0.001). Both groups had median abstinence of 3 days and no difference in sperm counts with a mean (median) count for the early group of 87.9 (75) versus 92.0 (76) for the recent group ( P  > 0.80). The significant drop in ejaculate volume was not reflected in a difference ( P  = 0.45) in total sperm numbers in the ejaculate with 320.7 (255) versus 313.1 (234).
Conclusion:  This study found no evidence of a decrease in sperm counts or total sperm output in men (excluding those with severe oligospermia) presenting for infertility investigations in Melbourne, Australia, over the last two decades of the twentieth century. (Reprod Med Biol 2004; 3 : 211–216)     

Quantitation by image analysis of global DNA methylation in human spermatozoa and its prognostic value in in vitro fertilization: a preliminary study

OBJECTIVE: To determine the relationship between sperm DNA methylation level and sperm characteristics and pregnancy rates. DESIGN: Prospective study. Quantitation by image analysis of DNA methylation in sperm nucleus. SETTING: Department of Reproduction Biology, Edouard Herriot Hospital, Lyon, France. PATIENT(S): Infertile couples undergoing IVF-ET. INTERVENTION(S): The immunostaining of 5 methyl-cytosine was performed on the spare sperm suspension that was used for an assisted reproduction technology procedure. MAIN OUTCOME MEASURE(S): Sperm characteristics according to World Health Organization criteria, sperm motility parameters with computer-assisted semen analysis, sperm DNA methylation level, and heterogeneity index (HI). RESULT(S): Sperm DNA methylation level and HI are correlated with sperm DNA characteristics. HI is negatively correlated with fertilization rate; sperm DNA methylation level is correlated with pregnancy rate. CONCLUSION(S): The DNA methylation level in human spermatozoa could be a new approach to evaluating the ability of spermatozoa to fertilize and lead to normal embryo development.     

No evidence for decreasing semen quality in four birth cohorts of 1,055 Danish men born between 1950 and 1970

Objective: To compare the quality of semen in 1,055 Danish men born between 1950 and 1970 who are assumed to represent a random sample of the Danish male population of fertile age.Design: Retrospective review of data on semen quality at the time of the female partner's first IVF treatment.Setting: The Fertility Clinic, Odense University Hospital, Odense, Denmark.Patient(s): One thousand fifty-five male partners of women with tubal infertility who were referred for IVF treatment consecutively during the period 1990–1996.Intervention(s): Analysis of the semen samples delivered and used in connection with the couples' first IVF treatment.Main Outcome Measure(s): Year of birth, age at time of sample collection, sperm concentration, and semen volume.Result(s): The mean sperm concentration (±SD) was 183.7 x 10⁶ mL and the mean semen volume (±SD) was 3.9 mL. A considerable variation in both parameters was found from year to year, but no significant change occurred in either parameter throughout the entire period. When four birth cohorts were compared, a later year of birth was not associated with any change in sperm concentration or semen volume.Conclusion(s): Sperm concentration and semen volume were not related to year of birth, indicating that sperm quality has not changed in the Danish male population during the last 20–30 years.