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-α, 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.     

Male infertility

Infertility affects 13-18% of couples and growing evidence from clinical and epidemiological studies suggests an increasing incidence of male reproductive problems. The pathogenesis of male infertility can be reflected by defective spermatogenesis due to pituitary disorders, testicular cancer, germ cell aplasia, varicocele and environmental factors or to defective sperm transport due to congenital abnormalities or immunological and neurogenic factors. Recent studies suggest an increased incidence of genetic disorders related to male infertility which may affect different levels, interfering with germ cell generation and maturation or leading to the production of non-functional spermatozoa. The identification of genetic causes of male infertility raises the issue of the transmission of defects to the offspring, a situation that is becoming more important given the increasing use of intracytoplasmic sperm injection (ICSI), a procedure in which the natural selection of the spermatozoa is by-passed. Fertilization can occur in vitro using ejaculated, epididymal or testicular spermatozoa, either fresh or frozen-thawed, providing opportunities hitherto not possible for men to be genetic fathers.     

The effects of male aging on semen quality,sperm DNA fragmentation and chromosomal abnormalities in an infertile population

Purpose  

To investigate the effects of male aging on semen quality, DNA fragmentation and chromosomal abnormalities in the spermatozoa of infertile patients and fertile men.     

Evolution of male fertility as a function of age and risks in progeny

Testicular aging starts form age 30 with progressive deterioration of vascularization, the density of capillaries, the diminution of the efficacy of the blood-testis barrier, the aging of Sertoli cells, which results in fall of production of androgen-binding protein. These changes lead to a slow reduction of the number of spermatozoa, although it is their quality that is responsible for male fertility. Analysis of the number, morphology, and mobility of spermatozoa of men aged 25-59 showed that the quality varies depending on age: the maximum values are reached between age 25 and 35, decreasing afterwards. The aging finally results in a degradation of the number and especially in the quality of spermatozoa, which is not satisfactory in individuals of very young age either. Whether male of female, parental aging poses a problem, because fertility diminishes and the risk of anomalies of the conceptus increase with the age of parents. It has been demonstrated that the new, autosomal dominant mutations responsible for fetal deaths or the numerous malformation syndromes, such as achondroplasia, Apert's disease, ossifying fibrodysplasia, and Marfan's syndrome, may be linked to paternal aging. The frequency of each of these syndromes is very low: 15-28 cases per million births for achondroplasia. Also, the frequency of anomalies attributable to paternal aging after the 40s reaches .3-.5% of births. Neurofibromatosis or von Recklinghausen's disease, hemophilia A, the myopathy of Duchenne, schizophrenia, and the performance of 18-year-old males on psychometric tests have been associated with paternal aging. The aging of gonads cannot be prevented, but one could avoid the consequences of the aging of gametes by avoiding having children after 35 or 40 years of age. This has been recommended to women for about 15 years, and perhaps should also be recommended to men.     

Human male infertility: a complex multifactorial phenotype

Infertility is a major reproductive health problem affecting 10% to 15% of couples, with approximately equal contributions. Spermatogenesis is a dynamic and multistep process of male germ cell proliferation and differentiation by which spermatozoa are produced from primordial germ cells. The causes of spermatogenic defects in infertile men are multifactorial and many environmental, nutritional, behavioral and genetic factors affect male infertility. In most of the infertile cases, the underlying mechanisms remain obscure. Genomics and proteomics offer new tools for better understanding the genetics of male infertility. The current review provides insights into the plausible chromosomal, genetic and epigenetic alterations, which may result into infertile phenotype.     

Viability of spermatozoa in the human ejaculate after vasectomy.

Ejaculates produced by 82 men between 6 and 19 days after removal of approximately 5 cm of vas deferens were assessed specifically for motility of residual spermatozoa. Several of 23 ejaculates produced 6 to 8 days after vasectomy still contained spermatozoa of the quality and number likely to produce pregnancy. By 13 to 15 days, however, all or the great majority of residual spermatozoa were dead, and in only 1 of 50 men were there numbers of motile spermatozoa possibly compatible with fertility. The results seem to justify more extensive surveys to confirm the absolute or biologic limits of the viability of spermatozoa in the terminal portion of the human male reproductive tract, anticipated here to be 16 to 18 days, as a suggested basis for a standard postvasectomy protocol. Second, these data support the choice of the 3rd postoperative week as the earliest rational moment to confirm the absence of motile spermatozoa, or in their presence to suspect an incomplete block.     

Implication of apoptosis in sperm cryoinjury

Apoptosis is an ongoing physiological phenomenon that has been documented to play a role in male infertility, if deregulated. Caspase activation, externalization of phosphatidylserine, alteration of mitochondrial membrane potential and DNA fragmentation are markers of apoptosis found in ejaculated human spermatozoa. These markers appear in excess in subfertile men and functionally incompetent spermatozoa. Sperm cryopreservation is a widely used procedure in the context of assisted reproductive techniques. Cryopreservation and thawing is a procedure that inflicts irreversible injury on human spermatozoa. The damage is manifested by a decrease in recovery of viable spermatozoa with optimum fertilization potential. This review describes the implication of apoptosis as one of the possible mechanisms involved in sperm cryoinjury. Evidence shows significant increase in some apoptosis markers following cryopreservation and thawing. On the other hand, the increase in sperm DNA fragmentation following cryopreservation and thawing requires further investigation. Specific technical measures should be applied to minimize the induction of apoptosis in human spermatozoa during cryopreservation and thawing. These include standardization of freezing protocols and cryoprotectant use. Selection of non-apoptotic spermatozoa may also prove to be of benefit.Apoptosis, also termed selective cell death, is a phenomenon that affects cell viability. The process has been documented in human spermatozoa and is implicated in the failure of fertilization following assisted reproductive techniques. There are several markers of apoptosis that present in ejaculated human spermatozoa, especially in those from infertile men. Freezing and thawing of human spermatozoa is commonly used nowadays in conjunction with assisted reproductive techniques such as intrauterine insemination and IVF. Sperm freezing is also used to preserve fertility in men undergoing cancer treatment or before undergoing vasectomies. Therefore, it is important to ensure that frozen–thawed spermatozoa will maintain its fertilizing capability. Despite recent methodological advances, freezing exerts detrimental effects on spermatozoa that lead to significant decreases in sperm viability and motility and ultimately in fertilization potential. The process of freezing and thawing increases the amount of apoptotic spermatozoa, which in turn is expected to decrease the success rates of assisted reproductive techniques. Therefore, current protocols for sperm freezing and thawing should be carefully evaluated to ensure minimizing the extent of apoptosis induction. The integration of novel techniques that isolate non-apoptotic spermatozoa also increases sperm survival following freezing and thawing.     

Endocrinology of the aging male

Despite enormous medical progress during the past few decades, the last years of life are still accompanied by increasing ill health and disability. The ability to maintain active and independent living for as long as possible is a crucial factor for ageing healthily and with dignity. The most important and drastic gender differences in aging are related to the reproductive organs. In distinction to the course of reproductive ageing in women, with the rapid decline in sex hormones expressed by the cessation of menses, men experience a slow and continuous decline. This decline in endocrine function involves: a decrease of testosterone, dehydro epiandrosterone (DHEA), oestrogens, thyroid stimulating hormone (TSH), growth hormone (GH), IGF1, and melatonin. The decrease of sex hormones is concomitant with a temporary increase of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In addition sex hormone binding globulins (SHBG) increase with age resulting in further lowering the concentrations of free biologically active androgens. These hormonal changes are directly or indirectly associated with changes in body constitution, fat distribution (visceral obesity), muscle weakness, osteopenia, osteoporosis, urinary incontinence, loss of cognitive functioning, reduction in well being, depression, as well as sexual dysfunction. The laboratory and clinical findings of partial endocrine deficiencies in the aging male will be described and discussed in detail. With the prolongation of life expectancy both women and men today live 1/3 of their life with endocrine deficiencies. Interventions such as hormone replacement therapy may alleviate the debilitating conditions of secondary partial endocrine deficiencies by preventing the preventable and delaying the inevitable.     

Medical treatment to improve sperm quality

Approximately 30% of cases of couple infertility are due to a male factor. Several conditions can interfere with spermatogenesis and reduce sperm quality and production. Treatable conditions, such as hypogonadism, varicocele, infections and obstructions, should be diagnosed and corrected, but many aspects of male factor infertility remain unclear. Various agents have been used in the attempt to increase the fertility potential of subjects with idiopathic oligoteratoasthenozoospermia. The rationale of medical treatment to improve sperm quality in these subjects has been questioned by the introduction of assisted reproductive technologies. However, there is now growing awareness of the importance of good quality spermatozoa for embryonic development and higher birth rates. Confounding factors in assessing the efficacy of male infertility treatments have erroneously inflated the superiority of assisted reproductive technologies over conventional approaches. A systematic review is given of relevant randomized controlled trials and effects on semen parameters. The analysis reveals that although results are heterogeneous, gonadotrophins, anti-oestrogens, carnitine and trace elements may be beneficial in improving sperm quality, although their effect on pregnancy rate remains controversial. The most common drug regimens are compared and an estimate of the results expected from these treatments provided.     

Proteomics,oxidative stress and male infertility

Oxidative stress has been established as one of the main causes of male infertility and has been implicated in many diseases associated with infertile men. It results from high concentrations of free radicals and suppressed antioxidant potential, which may alter protein expression in seminal plasma and/or spermatozoa. In recent years, proteomic analyses have been performed to characterize the protein profiles of seminal ejaculate from men with different clinical conditions, such as high oxidative stress. The aim of the present review is to summarize current findings on proteomic studies performed in men with high oxidative stress compared with those with physiological concentrations of free radicals, to better understand the aetiology of oxidative stress-induced male infertility. Each of these studies has suggested candidate biomarkers of oxidative stress, among them are DJ-1, PIP, lactotransferrin and peroxiredoxin. Changes in protein concentrations in seminal plasma samples with oxidative stress conditions were related to stress responses and to regulatory pathways, while alterations in sperm proteins were mostly associated to metabolic responses (carbohydrate metabolism) and stress responses. Future studies should include assessment of post-translational modifications in the spermatozoa as well as in seminal plasma proteomes of men diagnosed with idiopathic infertility.Oxidative stress, which occurs due to a state of imbalance between free radicals and antioxidants, has been implicated in most cases of male infertility. Cells that are in a state of oxidative stress are more likely to have altered protein expression. The aim of this review is to better understand the causes of oxidative stress-induced male infertility. To achieve this, we assessed proteomic studies performed on the seminal plasma and spermatozoa of men with high levels of oxidative stress due to various clinical conditions and compared them with men who had physiological concentrations of free radicals. A variety of sperm and seminal plasma proteins were found to be expressed either in abundance (over-expressed) or in a lesser amount (underexpressed), while other proteins were found to be unique either to men with oxidative stress or to men with a balanced ratio of antioxidants/free radicals. Each study included in this review suggested several proteins that could possibly act as biomarkers of oxidative stress-induced male infertility, such as protein DJ-1, PIP, lactotransferrin and peroxiredoxin. Pathway analysis performed in these studies revealed that the changes in seminal plasma proteins in men with oxidative stress could be attributed to stress responses and regulatory pathways, while changes in sperm proteins were linked to stress responses and metabolic responses. Subsequent studies could look into post-translational modifications in the protein profile of men with idiopathic infertility. We hope that the information in this review will contribute to a better understanding of the main causes of idiopathic male infertility.     

Spermatogenesis protection: myth or reality?

The male reproductive system is especially sensitive to the deleterious effects of many natural environmental agents, the workplace, and medical agents. Immunosuppressants and anticancer agents, which improve the prognosis of survival or the quality of life of patients, induce temporary sterility in all treated patients and complete sterility in 50% of treated patients. These agents affect spermatogenesis. Quantitative effects include oligo- and azoospermia. Qualitative effects involve spermatozoa changes, which inhibit implantation and their ability to fertilize the ovum and adversely affect embryonic development. Research is and has been underway to identify possible ways to preserve spermatogenesis. The Centers for the Study and Conservation of Human Sperm (CECOS) in France receives sperm every year from many men with cancer, especially Hodgkin's disease or testicular cancer, who wish CECOS to preserve their sperm through cryopreservation before they undergo chemotherapy or radiotherapy. Using less deleterious agents instead of cytotoxic drugs is a possible means to protect spermatogenesis. Agents which have been tested include antioxidants, gonadotropin-releasing hormone analogs, follicle stimulating hormone, and steroids. Of these agents, medroxyprogesterone acetate and testosterone together (MPA + T) have been examined the most in rats (contraception and protection) and in men (contraception). The rat studies show that MPA + T can indeed protect spermatogenesis. Clinical trials in men are needed to support these findings. INSERM supports a multidisciplinary group examining spermatogenesis preservation called Prosperm, which will likely be the impetus for the start-up of such clinical trials. Prosperm members include researchers and physicians who network to keep each other up-to-date on spermatogenesis protection. Their collaboration is especially needed, since recent epidemiological studies indicate that diverse environment factors adversely affect spermatogenesis.     

45,X/46,X,r(Y) karyotype transmitted by father to son after intracytoplasmic sperm injection for oligospermia. A case report.

BACKGROUND: The advent of assisted reproductive techniques, such as intracytoplasmic sperm injection (ICSI), has permitted conception and successful pregnancy for an increasing population of infertile men. Approximately 13.7% of infertile men with aspermia and 4.6% with oligospermia have a coexistent chromosome abnormality. Although the ICSI procedure appears safe thus far, early studies are in progress to evaluate outcomes of such pregnancies. For men whose infertility is linked to genetic conditions, it is an unprecedented challenge to predict the potential effects on their offspring. CASE: At 18 weeks' gestation, a 45,X/46,X,r(Y) karyotype was found on genetic amniocentesis performed for advanced maternal age. The pregnancy was achieved by ICSI using sperm from the husband, who was infertile due to severe oligospermia. Subsequently the same karyotype was found in the father. To our knowledge, this is the first reported case of familial transmission of ring Y chromosome. CONCLUSION: It is strongly recommended that ICSI and other new assisted reproductive techniques be preceded by genetic screening for male infertility as well as other indications warranted by the family history since traditional risk assessment may require revision and outcomes may be uncertain in some cases.     

Has the fertility of Danish men declined through the years in terms of semen quality? A comparison of semen qualities between 1952 and 1972

The semen analysis of 1,077 men examined in 1952 was compared with the semen analysis of 1,000 men examined in 1972 in order to assess if fertility in Danish men has declined during the period. The men on both occasions were examined because of a fertility problem. In 1952 6.2% of the men had azoospermia compared with 3.9% in 1972 (P less than 0.05). Between 1952 and 1972 there was a fall in sperm count (P less than 0.01, median 73.4, and 54.5 mill/ml), a deterioration in spermatozoa motility (P less than 0.001), an increase in number of abnormal spermatozoa (P less than 0.01, median 26.0%, and 44.8%), and a deterioration in fertility class according to the Hammen system (P less than 0.001). Semen volume and number of immobile spermatozoa did not change. This study of Danish men, like studies from other industrialized countries, indicates a fall in semen quality and male fertility since the early fifties.     

Therapeutic considerations in the management of the climacteric. A critical analysis of prevalent treatments

The natural aging process affects a woman greatly during the climacteric; hormonal patterns, metabolic parameters, reproductive target organs and bone are involved. In every instance one can compare these changes with the effects of hormone-replacement therapy (HRT) on these same parameters. Therapy should reverse the negative trends imposed by the aging process and preserve the status quo. The approach must be holistic, and consideration must be given to the effects of HRT on all the parameters and not just to the uterus as the sole end point. Ideally the smallest amount of hormone should be used that will effectively treat symptoms and favorably affect metabolic parameters, the reproductive target organs and bone. Since recent clinical evidence has emphasized the protective nature of estrogen-plus-progestagen therapy in the prevention of endometrial and breast cancer and of osteoporosis, combination therapy is an essential feature of treatment. The shortfalls in our knowledge of the ideal therapy are undeniable. However, it is crucial to provide hormonal support with the available therapy to the woman suffering from estrogen-deficiency symptoms, particularly in view of the high mortality rates associated with postmenopausal osteoporosis, a preventable disease.     

Localization of porcine seminal plasma (PSP) proteins in the boar reproductive tract and spermatozoa

Spermadhesins are proteins containing a characteristic CUB domain, originally isolated from seminal plasma and ejaculated spermatozoa in domestic animals. Boar spermadhesins are multifunctional proteins exhibiting ligand-binding abilities with various endogenous ligands present in the male and female reproductive tracts and may play a role in the reproduction process. Porcine spermadhesins (AQN, AWN, PSP protein families) are secreted mainly by the seminal vesicles, but their mRNAs have been found also in the cauda epididymis and prostate. Unlike AQN and AWN spermadhesins, localization of porcine seminal plasma (PSP) proteins in the boar reproductive tract has not been completely resolved. This work has focused on PSP protein expression and localization in the boar reproductive organs and on spermatozoa. Using specific rabbit polyclonal antibodies (anti-PSP I and anti-PSP II), PSP I and PSP II proteins were immunodetected in tissue extracts and in secretory tissues of cauda epididymis, prostate, seminal vesicles and Cowper's glands on the blots and by an indirect immunofluorescence technique, respectively. Moreover, the ability of PSP proteins to bind to epididymal spermatozoa indicated their presence on cauda epididymal and ejaculated spermatozoa. Porcine seminal plasma proteins bind to the sperm surface at ejaculation and may modulate several aspects of sperm activity during reproduction. PSP proteins are produced not only by seminal vesicles and prostate, but also by epididymis. However, their prospective role in sperm epididymal maturation is not clear. Further characterization of seminal plasma protein forms expressed in the individual reproductive organs will help to understand their subsequent role in the reproduction process.     

Pharmacological action and therapeutic effects of glutathione on hypokinetic spermatozoa for enzymatic-dependent pathologies and correlated genetic aspects

In this study, the pharmacologic substance reduced glutathione (GSH) was used in men with hypofertility problems linked to varicocele, in bulls with spermatozoa hypomobility due to varicocele, and in rabbits with dispermy caused by cryptorchidism. An efficacious therapeutic effect of increased motility of the spermatozoa was seen in subjects who were submitted to appropriate doses of glutathione I.M. GSH also showed some neutralizing effect on the catabolytes produced during spontaneous or induced peroxidation processes of the unsaturated lipids contained in the membranes of male germinal cells. The genetic aspects of the involved enzymes were also evaluated and the research was extended in vitro by incubating samples of spermatozoa with arachidonic acid homogenates, L-tryptophan, hematein, and with an addition of glutathione. The results showed that polynsaturated fatty acid metabolic substances (PUFA) play an important role in the acrosomal reaction of spermatozoa and that GSH has a determining role in increasing the motility of spermatozoa with consequent improved fertilization. The spermatozoa of bulls provided us with a valid model to study for the morphostructural, biochemical and pharmacological analyses of human spermatozoa.     

Effects of dibromoacetic add on murine spermatozoa and testis

Background and Aims:   Bromoacetic acids are a by-product of water ozonation and dibromoacetic acid (DBAA) in particular, which is a by-product of disinfection, inhibits male reproductive functions. In order to understand its effects, the spermatozoa and testes of mice were exposed to DBAA.
Methods:   Twelve-week-old ICR mice were exposed to 10 p.p.m. DBAA. They were examined in regards to effects on the weights of body, testis and epididymis, the histological changes of tesits and the protein expression in testis.
Results:   Neither the bodyweight nor the weights of the testis and epididymis of the exposed mice was affected, but approximately 13% of spermatozoa obtained from the cauda epididymis were motile with a drop-shaped head, and structures resembling residual bodies were found in the testis. Moreover, the expression of two testis proteins was changed by exposure to DBAA.
Conclusions:   It was likely that DBAA inhibited male reproductive functions by disturbance of spermatogenesis via change of protein expression. (Reprod Med Biol 2004; 3: 85–93)     

Effects of triclocarban on intact immature male rat: augmentation of androgen action

Triclocarban (TCC; 3,4,4'-trichlorocarbanilide) is an antimicrobial agent used widely in various personal hygiene products including soaps. Recently, TCC has been shown to enhance testosterone-induced effects in vitro and to enlarge accessory sex organs in castrated male rats. This study was designed to evaluate the effects of TCC on intact age-matched male rats and on human prostate LNCaP and C4-2B cells. Seven-week-old male Sprague-Dawley rats received either a normal diet or a diet supplemented with TCC (0.25% in diet) for 10 days. Triclocarban induced hyperplasia of accessory sex organs in the absence of significant qualitative histological changes. Serum luteinizing hormone (LH) and testosterone were not significantly altered by TCC treatment. In prostate cancer-derived LNCaP and C4-2B cells, TCC potentiated androgen actions via androgen receptor-dependent actions. In conclusion, TCC significantly affects intact male reproductive organs and potentiates androgen effects in prostate cancer cells.     

Neuroendocrine changes with reproductive aging in women

Aging has dramatic effects on the reproductive system in women. Undoubtedly, the most notable changes in the neuroendocrine axis arise from the loss of ovarian function, and thus, the loss of negative feedback on the hypothalamus and pituitary. Progressive decreases in inhibin B and inhibin A result in an early increase in follicle-stimulating hormone (FSH), which initially maintains folliculogenesis and estradiol secretion. Over time, regular ovulatory cycles give way to inconsistent folliculogenesis and ovulation, dramatic swings in estradiol and gonadotropin levels, and markedly irregular cycles. Changes in estrogen positive feedback may contribute to cycle disruption. Studies in younger and older postmenopausal women indicate that changes in the neuroendocrine axis occur with aging that are independent of the changing ovarian hormonal milieu of the menopausal transition. Luteinizing hormone and FSH decrease progressively after the menopause, as does gonadotropin-releasing hormone (GnRH) pulse frequency. However, the overall amount of GnRH increases with aging, consistent with a significant degree of adaptability in the aging brain in women, and suggesting that aging alters pituitary responsiveness to GnRH. Estrogen negative feedback is not altered by aging; studies of the effects of aging on estrogen positive feedback are ongoing.     

Oxidative stress and its implications in female infertility - a clinician's perspective

Reactive oxygen species (ROS) have a role in the modulation of gamete quality and gamete interaction. Generation of ROS is inherent in spermatozoa and contaminating leukocytes. ROS influence spermatozoa, oocytes, embryos and their environment. Oxidative stress (OS) mediates peroxidative damage to the sperm membrane and induces nuclear DNA damage. ROS can modulate the fertilizing capabilities of the spermatozoa. There is extensive literature on OS and its role in male infertility and sperm DNA damage and its effects on assisted reproductive techniques. Evidence is accumulating on the role of ROS in female reproduction. Many animal and human studies have elucidated a role for ROS in oocyte development, maturation, follicular atresia, corpus luteum function and luteolysis. OS-mediated precipitation of pathologies in the female reproductive tract is similar to those involved in male infertility. OS influences the oocyte and embryo quality and thus the fertilization rates. ROS appears to play a significant role in the modulation of gamete interaction and also for successful fertilization to take place. ROS in culture media may impact post-fertilization development, i.e. cleavage rate, blastocyst yield and quality (indicators of assisted reproduction outcomes). OS is reported to affect both natural and assisted fertility. Antioxidant strategies should be able to intercept both extracellular and intracellular ROS. This review discusses the sources of ROS in media used in IVF-embryo transfer and strategies to overcome OS in oocyte in-vitro maturation, in-vitro culture and sperm preparation techniques.