Male infertility risk factors in a French military population

Deciphering the Nexus Between Oxidative Stress and Spermatogenesis: A Compendious Overview

Oxidative stress (OS) and reactive oxygen species (ROS) are one of the main reasons for the multifactorial concern - male infertility. ROS are active components of cellular metabolism that are intrinsic to cellular functioning and are present at minimal and unreactive levels in normal cells. They are an integral component of the sperm developmental physiology, capacitation, and function. As said "anything in excess is poison," so is the case with ROS. These, when produced in excess to the antioxidants present in the seminal plasma, cause multiple malformations during the process of spermatogenesis such as lipid peroxidation, interfere with capacitation, sperm DNA fragmentation and damage to the membrane of the sperm which in turn reduces the motility of the sperm and its ability to fuse with the oocyte. Exposure of spermatozoa to oxidative stress is a major causative agent of male infertility. Thus, a delicate balance between the beneficial and detrimental effects of ROS for proper functions is of utter importance. In this chapter, the influence of ROS in OS which is a key player in male infertility along with the diagnosis, available treatment, and prevention of extensive ROS buildup within the spermatozoa are highlighted.

5G mobile networks and health-a state-of-the-science review of the research into low-level RF fields above 6 GHz

The increased use of radiofrequency (RF) fields above 6 GHz, particularly for the 5 G mobile phone network, has given rise to public concern about any possible adverse effects to human health. Public exposure to RF fields from 5 G and other sources is below the human exposure limits specified by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). This state-of-the science review examined the research into the biological and health effects of RF fields above 6 GHz at exposure levels below the ICNIRP occupational limits. The review included 107 experimental studies that investigated various bioeffects including genotoxicity, cell proliferation, gene expression, cell signalling, membrane function and other effects. Reported bioeffects were generally not independently replicated and the majority of the studies employed low quality methods of exposure assessment and control. Effects due to heating from high RF energy deposition cannot be excluded from many of the results. The review also included 31 epidemiological studies that investigated exposure to radar, which uses RF fields above 6 GHz similar to 5 G. The epidemiological studies showed little evidence of health effects including cancer at different sites, effects on reproduction and other diseases. This review showed no confirmed evidence that low-level RF fields above 6 GHz such as those used by the 5 G network are hazardous to human health. Future experimental studies should improve the experimental design with particular attention to dosimetry and temperature control. Future epidemiological studies should continue to monitor long-term health effects in the population related to wireless telecommunications.

Heat stress response of somatic cells in the testis

The testis is a temperature-sensitive organ that needs to be maintained 2-7 °C below core body temperature to ensure the production of normal sperm. Failure to maintain testicular temperature in mammals impairs spermatogenesis and leads to low sperm counts, poor sperm motility and abnormal sperm morphology in the ejaculate. This review discusses the recent knowledge on the response of testicular somatic cells to heat stress and, specifically, regarding the relevant contributions of heat, germ cell depletion and inflammatory reactions on the functions of Sertoli and Leydig cells. It also outlines mechanisms of testicular thermoregulation, as well as the thermogenic factors that impact testicular function.

Down regulating PHGDH affects the lactate production of sertoli cells in varicocele

BACKGROUND

Although varicocele is considered to be one of the leading causes of male infertility, the precise mechanism underlying how varicocele leads to male infertility is not completely understood. We found the lactate concentration on the varicocele side of the patients was decreased compare with peripheral venous blood. In the testicles, the lactate produced by the sertoli cells through the glycolysis pathway provides most of the energy needed for spermatogenesis, the reduction of lactate will affect spermatogenesis. The objective of this study was to investigate the mechanism of this abnormal energy metabolism phenomenon in varicocele.

METHODS

In this study, we collected the testicular tissue from patients with varicocele, the glycolysis related proteins PHGDH was identified by iTRAQ proteomics technology. Experimental rat varicocele model was constructed according to our new clip technique, the mRNA and protein expression levels of PHGDH were examined with qRT-PCR and Western blotting. We constructed a sertoli cell of PHGDH down-regulation model, and then detected the glucose consumption, LDH activities and lactate production in the sertoli cells. Western blot was conducted to investigate the effects of PHGDH on the expression of phosphoserine phosphatase (PSPH) and Pyruvate kinase M2 (PKM2). Flow cytometry was used to detect the cell apoptosis and cell cycle in sertoli cells.

RESULTS

The results showed that testicular protein PHGDH was down-regulated in patients with varicocele and in experimental rat varicocele model. Down-regulation of PHGDH in sertoli cells significantly decreased the glucose consumption, LDH activities and lactate production in the sertoli cells, indicating that the low expression of PHGDH ultimately led to a decrease in lactate production by affecting the glycolysis. The Western blot results showed that the down-regulation of PHGDH significantly reduced the expression of pathway protein PSPH and PKM2, leading to the reduction of lactate production. Moreover, PHGDH knockdown can promote apoptosis and inhibit cell cycle to affect cell growth.

CONCLUSIONS

Overall, we conformed that varicocele lead to the decreasing of testis lactate production. Down-regulation of PHGDH in sertoli cells may mediate the process of abnormal glucose metabolism. Our study provide new insight into the mechanisms underlying metabolism-associated male infertility and suggests a novel therapeutic target for male infertility.

Fertility Preservation Before Deployment: Oocyte and Sperm Freezing in Members of the Active Duty Military

Active duty military service and deployment has the potential to compromise fertility through combat-related genitourinary injury, gonadotoxic exposures, and physical separation from a partner. Despite a growing interest among the military community as well as promising efficacy and safety data, fertility preservation remains an uncovered benefit for active duty soldiers. In 2016, the Pentagon proposed a program that would cover oocyte and sperm cryopreservation for any member of the active duty military desiring its use. Regrettably, that funding was not secured and predeployment fertility preservation remains an out-of-pocket expense. Today, advocacy groups, non-for-profit organizations, and physicians remain vigilant in their attempts to drive another government initiative through Congress. While activism continues, it is important to stress the value of fertility preservation counseling in soldiers' predeployment preparation and military family planning.

ETHNOBOTANICAL SURVEY OF PHOENIX DACTYLIFERA L. POLLEN USED FOR THE TREATMENT OF INFERTILITY PROBLEMS IN ALGERIAN OASES

Background:

The Phoenix dactylifera L. (date palm) is known for its traditional medicinal properties across the history of native population in Algerian Sahara. There is a large trend of consumption of date palm pollen preparations in many human infertility cases in our country. However, the validity has not been scientifically tested. There has been no direct scientific research on this application. This study was undertaken to identify cultivars with greater potential in the traditional medicine uses. To evaluate the effects of date palm pollen on some sexual behavioural parameters of male adult rats, we tested the role of pollen powder from Deglet Nour cultivar on some male reproductive parameters.

Materials and Methods:

An Ethnobotanical survey was conducted in 17 oases in southern Algeria to identify all cultivars with medicinal interest. Local people were interviewed with open questions. A questionnaire and personal interviews for data collection were designed to record important cultivars, parts used and preparations. To determine the active constituents of date palm pollen used in traditional medicine, a phytochemical screening was performed. The effects of oral administration of date palm pollen suspension on male adult rats were investigated on body and testicle weights, serum testosterone level.

Results:

131 prominent cultivars were found within 12 cultivars containing various parts with medicinal effects. Some primary and secondary metabolites were detected by phytochemical screening. The pollen increased the weight of the body, testicles and enhanced the serum testosterone level of male rats treated.

Conclusion:

The present survey has provided the identification and recognition of date palm cultivars used in traditional Saharan medicine. Date palm pollen could improve sexual activities in male infertility cases and may be attempted to derive drugs.

The effect of the degree of left renal vein constriction on the development of adolescent varicocele in Sprague-Dawley rats

Experimental models have allowed inquiry into the pathophysiology of varicocele (VC) beyond that possible with human patients. A randomized controlled study in rats was designed to clarify the influence of the degree of left renal vein constriction on the development of adolescent VC. Fifty adolescent male Sprague–Dawley rats (Rattus norvegicus) were randomly assigned to five groups of 10: the experimental groups (I–IV) underwent partial ligation of left renal veins with 0.5-, 0.6-, 0.7-, and 0.8-mm diameter needles, respectively. The control group (V) underwent a sham operation. The diameter of the left spermatic vein (LSV) was measured at baseline and 30 days postoperatively. In addition, the lesion of the left kidney was examined with the naked eye and assessed by Masson's trichrome staining. VC was successfully induced in 2 (20%), 4 (40%), 7 (70%), and 10 (100%) rats in groups I–IV, respectively. The other rats failed to develop VCs primarily due to left renal atrophy. No VC was observed in group V. The postsurgical LSV diameters in VC rats in groups III and IV were 1.54 ± 0.16 and 1.49 ± 0.13 mm, respectively (P > 0.05), and their increments were 1.36 ± 0.10 and 1.31 ± 0.10 mm, respectively (P > 0.05). These results suggest that suitable constriction of the left renal vein is critical for adolescent VC development. In addition, the 0.8-mm diameter needle may be more suitable for inducing left renal vein constriction in adolescent rat models.

Causes, effects and molecular mechanisms of testicular heat stress

The process of spermatogenesis is temperature-dependent and occurs optimally at temperatures slightly lower than that of the body. Adequate thermoregulation is imperative to maintain testicular temperatures at levels lower than that of the body core. Raised testicular temperature has a detrimental effect on mammalian spermatogenesis and the resultant spermatozoa. Therefore, thermoregulatory failure leading to heat stress can compromise sperm quality and increase the risk of infertility. In this paper, several different types of external and internal factors that may contribute towards testicular heat stress are reviewed. The effects of heat stress on the process of spermatogenesis, the resultant epididymal spermatozoa and on germ cells, and the consequent changes in the testis are elaborated upon. We also discuss the molecular response of germ cells to heat exposure and the possible mechanisms involved in heat-induced germ cell damage, including apoptosis, DNA damage and autophagy. Further, the intrinsic and extrinsic pathways that are involved in the intricate mechanism of germ cell apoptosis are explained. Ultimately, these complex mechanisms of apoptosis lead to germ cell death.

Male reproductive health and prostate cancer risk

PURPOSE OF REVIEW

Male infertility impacts a substantial proportion of men and has serious implication for a man's quality of life. Advances in reproductive technology may allow men to bypass urologic care in order to achieve their family planning goals. Recent data suggests that male reproductive failure may be a harbinger of future urologic diseases, including prostate cancer (CaP), thus emphasizing the importance of dedicated urologic evaluation and care for all male infertility patients.

RECENT FINDINGS

We will review the epidemiologic data that explores an association between male reproductive health and CaP. We will review the potential biologic mechanisms that may underlie this association, and explore possible reasons for inconsistencies in study findings.

SUMMARY

Studies of the association between male infertility and CaP are inconsistent. Despite this, the association between reproductive health in a man's fourth decade (30s) and his development of aggressive CaP in his sixth decade (50s) should not be ignored. These findings, combined with the robustness of the potential common underlying mechanisms, provide a foundation for future studies of male reproductive health that are more specific in their approach to answering questions about the association between male reproductive failure and future systemic disease.

Effects of varicocele on testosterone, apoptosis and expression of StAR mRNA in rat Leydig cells

The aim of this study was to explore the effects of varicocele on the morphology and function of Leydig cells in the rat testis. Forty male Sprague-Dawley rats were divided into two groups: the experimental group underwent surgery to create a left varicocele (VC), and the control group underwent a sham operation. Serum testosterone and intratesticular testosterone levels were measured using a radioimmunoassay after 4 and 8 weeks of operation. Leydig cells were studied for apoptosis and expression of steroidogenetic acute regulatory (StAR) protein mRNA levels. Serum testosterone levels declined after 4 and 8 weeks of operation but were not significant (P>0.05). However, the intratesticular testosterone levels after 8 weeks were significantly decreased compared with the control group (P<0.01). The mean apoptosis index of Leydig cells in the experimental group was significantly higher than that in the control group after 4 or 8 weeks (P<0.01). StAR mRNA levels in the Leydig cells of the experimental group were significantly lower compared to those of the control group (P<0.01). Our data show that varicocele did impair Leydig cell function by increasing apoptosis and suppressing the expression of the StAR protein.

The relationship between isolated teratozoospermia and clinical pregnancy after in vitro fertilization with or without intracytoplasmic sperm injection: a systematic review and meta-analysis

We conducted a systematic review and meta-analysis of data from the literature from the years 1986 to 2009 using teratozoospermia and fertilization or IVF or in vitro fertilization as the keywords. A total of 31 studies were identified, and 4 met the inclusion criteria. Isolated teratozoospermia was not associated with a statistically significantly decreased probability of pregnancy with assisted reproduction.

Effects of low-level radio-frequency (3kHz to 300GHz) energy on human cardiovascular, reproductive, immune, and other systems: A review of the recent literature

OBJECTIVES

Occupational or residential exposures to radio-frequency energy (RFE), including microwaves, have been alleged to result in health problems. A review of recent epidemiological studies and studies of humans as subjects in laboratory investigations would be useful.

METHODS

This paper is a narrative review of the recent medical and scientific literature (from mid-1998 through early 2006) dealing with possible effects of RFE on humans, relating to topics other than cancer, tumors, and central nervous system effects (areas covered in a previous review). Subject areas in this review include effects on cardiovascular, reproductive, and immune systems.

RESULTS

A large number of studies were related to exposures from cellular telephones. Although both positive and negative findings were reported in some studies, in a majority of instances no significant health effects were found. Most studies had some methodological limitations. Although some cardiovascular effects due to RFE were reported in epidemiological studies (e.g., lower 24-h heart rate, blunted circadian rhythm of heart rate), there were no major effects on a large number of cardiovascular parameters in laboratory studies of volunteers during exposure to cell-phone RFE. In population-based studies of a wide range of RFE frequencies, findings were equivocal for effects on birth defects, fertility, neuroblastoma in offspring, and reproductive hormones. Some changes in immunoglobulin levels and in peripheral blood lymphocytes were reported in different studies of radar and radio/television-transmission workers. Due to variations in results and difficulties in comparing presumably exposed subjects with controls, however, it is difficult to propose a unifying hypothesis of immune-system effects. Although subjective symptoms may be produced in some sensitive individuals exposed to RFE, there were no straightforward differences in such symptoms between exposed and control subjects in most epidemiological and laboratory studies. Consistent, strong associations were not found for RFE exposure and adverse health effects. The majority of changes relating to each of the diseases or conditions were small and not significant.

CONCLUSIONS

On the basis of previous reviews of older literature and the current review of recent literature, there is only weak evidence for a relationship between RFE and any endpoint studied (related to the topics above), thus providing at present no sufficient foundation for establishing RFE as a health hazard.

Infertility among couples in a population-based study in Iran: prevalence and associated risk factors

To explore the prevalence and risk factors of infertility in Iran, a total of 12 285 ever-married women aged 15-50 years old and their husbands (if available) were interviewed by 82 female general practitioners and answered a self-administered questionnaire on several aspects of infertility. They were identified from the national population in 30 counties, and invited to a confidential interview. Data were obtained about their age, education, marital status, toxic habits, medical history, disabilities and illnesses, help-seeking, economy, ethnicity, geographic location, contraceptive use and age at which they had first intercourse. This study used the definition of childlessness proposed by World Health Organization: 'the woman has never conceived despite cohabitation and exposure to pregnancy for a period of 2 years'. The overall prevalence of infertility was 8% (95% CI: 3.2-15.0). The weighted national estimate of primary infertility was 4.6% (95% CI: 3.6-5.2). There was a pronounced regional pattern in the levels of primary infertility. The primary infertility increased significantly from 2.6 to 4.3 to 5.5% for the 1985-1989, 1990-1994 and 1995-2000 marriage cohorts. The prevalence of secondary infertility was 3.4% (95% CI: 2.4-5.1). Overall the prevalence of infertility falls within a relatively wide range being high in the Southern counties, and low in the Northern counties. The probability of first pregnancy at the end of 2 years of marriage was 0.78 for all ever-married women. The prevalence of infertility increased with age (linear chi-square 198.012, 1 d.f., p = 0.01). The age pattern of infertility also varies quite markedly across the counties analysed. No effect of race was detected; neither the intercept (analysis of covariance p = 0.36) nor the slope of the age relationship was influenced by race (analysis of covariance p = 0.41). Infertility were observed as significantly higher in the presence of history of tubo-ovarian surgery [odds ratio (OR): 1.43; 95% CI: 1.28-2.23; p = 0.01], salpingitis (OR: 2.34; 95% CI: 1.31-4.3; p = 0.016), ectopic pregnancy (OR: 2.45; 95% CI: 1.90-3.44; p = 0.04), varicocele (OR: 2.85; 95% CI: 1.61-5.20; p = 0.01) and cryptorchidism (OR: 3.81; 95% CI: 2.51-4.28; p = 0.031). This study provides a quantitative estimate of the prevalence and main risk factors for infertility in Iranian couples. Yet, further studies on the cause of primary and secondary infertility and geographical variations in the incidence and prevalence of infertility in Iran are needed.

Male gonadal dose of ionizing radiation delivered during X-ray examinations and monthly probability of pregnancy: a population-based retrospective study

Background

Male gonadal exposure to ionizing radiation may disrupt spermatogenesis, but its influence on the fecundity of couples has been rarely studied. We aimed to characterize the influence of male gonadal dose of ionizing radiation delivered during radiodiagnostic on the monthly probability of pregnancy.

Methods

We recruited a random sample of women who retrospectively described 1110 periods of unprotected intercourse beginning between 1985 and 1999 and leading either to a live birth or to no pregnancy; their duration was censored after 13 months. The male partner answered a telephone questionnaire on radiodiagnostic examinations. We assigned a mean gonadal dose to each type of radiodiagnostic examination. We defined male dose for each period of unprotected intercourse as the sum of the gonadal doses of the X-ray examinations experienced between 18 years of age and the date of discontinuation of contraception. Time to pregnancy was analysed using a discrete Cox model with random effect allowing to estimate hazard ratios of pregnancy.

Results

After adjustment for female factors likely to influence fecundity, there was no evidence of an association between male dose and the probability of pregnancy (test of homogeneity, p = 0.55). When compared to couples with a male gonadal dose between 0.01 and 0.20 milligrays (n = 321 periods of unprotected intercourse), couples with a gonadal dose above 10 milligrays had a hazard ratio of pregnancy of 1.44 (95% confidence interval, 0.73–2.86, n = 31).

Conclusion

Our study provides no evidence of a long-term detrimental effect of male gonadal dose of ionizing radiation delivered during radiodiagnostic on the monthly probability of pregnancy during the year following discontinuation of contraceptive use. Classification errors due to the retrospective assessment of male gonadal exposure may have limited the statistical power of our study.

Reproductive toxicology in occupational settings: an update

OBJECTIVE

This article mainly attempts to review the recent human literature on the adverse effects of occupational factors on fertility, developmental effects and genetic changes in the germ line, which lead to genetic malformations or to genetic disease. The secondary study aim is to answer whether occupational exposures are quantitative momentously for 15% involuntarily childless couples, 10-20% spontaneous abortions and 3% birth defects.

METHODS

A literature survey was conducted for publications on these subjects focusing on the latest publications. PubMed (Medline. 2005) was used for this literature search.

RESULTS

Publication bias and a large amount of confounding factors, which have to be controlled, make the design of human fertility studies difficult. Epidemiologic studies using time to conception techniques have been useful in identifying substances and exposure scenarios with proven toxic effect on fertility. The collected studies suggest that the exposure to the following substances or occupational settings may affect fertility function: lead, organic mercury compounds, manganese, carbon disulfide, 2-bromopropane and dibromochloropropane, welding, professional driving and working with heat. Concerning developmental effects even for methyl mercury, which was in group A of the German MAK list, to date no reliable evidence of the damaging effect on the human fetus under actual work conditions has been obtained. It is also difficult to classify substances according to their mutagenic potential for the germ cell, since no direct evidence of an association between exposure against a physical or chemical pollutant and the occurrence of a hereditary disorder has been found yet.

CONCLUSION

In conclusion there are only a few substances which may affect reproductive function in the workplace without a doubt. The decreasing fertility of women in Western countries can be explained by the increasing female reproduction age, rather than by occupational exposures. Also the rates for spontaneous abortions and birth defects cannot be explained by industrial exposures at the workplace.