Chemicals in the environment and human male fertility

Regional difference in semen quality of young men: a review on the implication of environmental and lifestyle factors during fetal life and adulthood

The prevalence of low semen quality and the incidence of testicular cancer have been steadily increasing over the past decades in different parts of the World. Although these conditions may have a genetic or epigenetic origin, there is growing evidence that multiple environmental and lifestyle factors can act alone or in combination to induce adverse effects. Exposure to these factors may occur as early as during fetal life, via the mother, and directly throughout adulthood after full spermatogenic capacity is reached. This review aims at providing an overview of past and current trends in semen quality and its relevance to fertility as well as a barometer of men’s general health. The focus will be on recent epidemiological studies of young men from the general population highlighting geographic variations in Europe. The impact of some lifestyle and environmental factors will be discussed with their role in both fetal life and adulthood. These factors include smoking, alcohol consumption, psychological stress, exposure to electromagnetic radiation, and Endocrine Disrupting Chemicals (EDCs). Finally, the challenges in investigating the influence of environmental factors on semen quality in a fast changing world are presented.

Comparison effects of olive leaf extract and oleuropein compounds on male reproductive function in cyclophosphamide exposed mice

Spermatogenesis is a complicated process in which sperm is susceptible to various chemotherapy drugs such as cyclophosphamide (CP). As olive leaf extract (OLE) and its active ingredient, oleuropein, have variousantioxidant, anti-apoptotic, and anti-inflammatory properties the aim of the present study was to investigate the effects of OLE and oleuropein on male reproductive function focusing antioxidative effects and histological modifications in the testes of CP-exposed mice. In order to do this, 80 NMRI male mice were divided into eight groups including control group, group received CP, group received OLE, group received oleuropein, group received OLE following CP exposure, group received oleuropein following CP exposure, group received OLE plus oleuropein and group received OLE plus oleuropein following CP exposure. In all groups CP (single dose of 100 mg/kg (, OLE (100 mg/kg for consequence 28 days) and oleuropein (100 mg/kg for consequence 28 days) were injected intraperitoneally. Moreover, testis histology, sperm parameters and serum levels of LH, FSH, MDA and antioxidant capacity were investigated. Results showed that CP caused oxidative state and abnormal changes in sperms and testes. Besides, treatments with oleuropein and OLE led to mitigate the harmful effects of CP on the male reproductive system. In conclusion, our findings showed that olive's compounds can diminish the hazardous effects of CP on spermatogenesis in mice.

Biological Effects of Magnetic Resonance Imaging on Testis Histology and Seminiferous Tubules Morphometry

Objectives

Spermatogenesis is a regular and lengthy process in which the function of testicular cells may potentially be influenced by several extrinsic and intrinsic stressors, including environmental factors such as magnetic resonance imaging (MRI) waves and radiation. Our study aimed to investigate the effects of MRI waves and fields on the testicular histology and morphometry of seminiferous tubules in mice.

Methods

The experiment was conducted on 40 adult Naval Medical Research Institute mice. The control group was located in the center of the MRI bore while it was turned off, while the exposed group was exposed to the active scanner for 36 minutes once a week for three weeks. Our study included four groups: group I (control group at one hour after last exposure), group II (experimental group at one hour after last exposure), group III (control group at 35 days after last virtual exposure), and group IV (experimental group at 35 days after last exposure). We then assessed the tube and lumen diameters, as well as epithelium thickness of the seminiferous tubules.

Results

Our data showed that MRI waves partially reduced testicular weight one hour after the last exposure (group II) compared to group I (p = 0.240). On the other hand, in group II the Johnson’s score (score 10, complete spermatogenesis and perfect tubules) was 87.5% which was slightly less than recorded in groups I, III, and IV (91.4%, 92.2%, and 90.5%, respectively). Furthermore, the MRI in group II revealed induces vacuolization in the epithelium, arrest in primary spermatocytes in the pachytene stage as well as disruption in the testicular parenchyma.

Conclusions

Long-term exposure to MRI waves has deleterious effects on the male reproductive system, fertility parameters, and the quantity of germ cells in the seminiferous tubules with the exception of the number of round spermatid cells and epithelial thickness. All these effects were reversible after a new period of spermatogenesis.

Screening targeted testis‑specific genes for molecular assessment of aberrant sperm quality

Teratospermia is a heterogeneous and complex disorder, which is closely associated with male fertility. Genes and gene products associated with teratospermia may serve as targeted biomarkers that help understand the underlying mechanisms of male infertility; however, systematic information on the subject remains to be elucidated. The present study performed a comparative bioinformatics analysis to identify biomarkers associated with sperm quality, particular focusing on testis-specific biomarkers. A stepwise screening approach identified 1,085 testis/epididymis-specific genes and 3,406 teratospermia-associated genes, resulting in 348 testis-specific genes associated with aberrant sperm quality. These genes were functionally associated with the reproduction process. Gene products corresponding to heat shock protein family A (Hsp70) member 4 like (HSPA4L) and phosphoglycerate kinase 2 were characterized at the cellular level in human testes and ejaculated spermatozoa. HSPA4L expression in sperm was revealed to be associated with sperm quality. The present study provided a novel insight into the understanding of sperm quality, and a potential method for the diagnosis and assessment of sperm quality in the event of male infertility.

Effect of chronic cabergoline treatment and testosterone replacement on metabolism in male patients with prolactinomas

INTRODUCTION

Hyperprolactinemia and hypogonadism are reportedly associated with an impaired metabolic profile. The current study aimed at investigating the effects of testosterone replacement and cabergoline (CAB) treatment on the metabolic profile in male hyperprolactinemic patients.

PATIENTS AND METHODS

Thirty-two men with prolactinomas, including 22 with total testosterone (TT) <8 nmol/l (HG, 69%) and 10 with TT >8 nmol/l (non-HG, 31%), were entered in the study. In all patients, metabolic parameters were assessed at diagnosis and after 12- and 24-month treatment.

RESULTS

Compared to non-HG patients, at baseline the HG patients had higher waist circumference (WC). TT significantly correlated with body mass index (BMI). Twelve-month CAB induced PRL normalization in 84%. HG prevalence significantly decreased (28%) and non-HG prevalence significantly increased (72%). Anthropometric and lipid parameters, fasting insulin (FI), insulin sensitivity index (ISI0), homeostatic model assessment of insulin secretion (HOMA-β) and homeostatic model assessment of insulin resistance (HOMA-IR) significantly improved compared to baseline. TT was the best predictor for FI. Percent change (Δ) of TT significantly correlated with ΔCholesterol, ΔWeight and ΔBMI. Compared to non-HG patients, the HG patients had a higher weight, BMI, WC and HOMA-β. In HG, testosterone replacement was started. After 24 months, PRL normalized in 97%. HG prevalence significantly decreased (6%) and non-HG prevalence significantly increased (94%). Anthropometric and lipid parameters, FI, ISI0, HOMA-β and HOMA-IR significantly improved compared to baseline, with FI, ISI0, HOMA-β and HOMA-IR further ameliorating compared to the 12-month evaluation. Compared to non-HG patients, the HG patients still had a higher weight, BMI and WC.

CONCLUSIONS

In hyperprolactinemic hypogonal men, proper testosterone replacement induces a significant improvement in the metabolic profile, even though the amelioration in the lipid profile might reflect the direct action of CAB.

Parallel assessment of male reproductive function in workers and wild rats exposed to pesticides in banana plantations in Guadeloupe

BACKGROUND

There is increasing evidence that reproductive abnormalities are increasing in frequency in both human population and among wild fauna. This increase is probably related to exposure to toxic contaminants in the environment. The use of sentinel species to raise alarms relating to human reproductive health has been strongly recommended. However, no simultaneous studies at the same site have been carried out in recent decades to evaluate the utility of wild animals for monitoring human reproductive disorders. We carried out a joint study in Guadeloupe assessing the reproductive function of workers exposed to pesticides in banana plantations and of male wild rats living in these plantations.

METHODS

A cross-sectional study was performed to assess semen quality and reproductive hormones in banana workers and in men working in non-agricultural sectors. These reproductive parameters were also assessed in wild rats captured in the plantations and were compared with those in rats from areas not directly polluted by humans.

RESULTS

No significant difference in sperm characteristics and/or hormones was found between workers exposed and not exposed to pesticide. By contrast, rats captured in the banana plantations had lower testosterone levels and gonadosomatic indices than control rats.

CONCLUSION

Wild rats seem to be more sensitive than humans to the effects of pesticide exposure on reproductive health. We conclude that the concept of sentinel species must be carefully validated as the actual nature of exposure may varies between human and wild species as well as the vulnerable time period of exposure and various ecological factors.

Cloning and identification of a novel sperm binding protein, HEL-75, with antibacterial activity and expressed in the human epididymis

BACKGROUND

The HEL-75 protein is a beta-defensin that was identified by analyzing a human epididymis cDNA library. Studying its function may not only elucidate the mechanisms of host defense, but may also provide new alternatives for novel therapeutic drugs for reproductive tract infections.

METHODS

The HEL-75 gene was amplified by PCR, and its structure and function were predicted and analyzed with bioinformatics tools. Polyclonal serum was raised against recombinant HEL (rHEL)-75 protein. The gene expression pattern was analyzed with RT-PCR and immunofluorescent staining. Finally, the antimicrobial activity and function during fertilization of HEL-75 were analyzed using a colony-forming unit assay and IVF, respectively.

RESULTS

The human HEL-75 gene is located on chromosome 20p13 and encodes a 95 amino acid protein with a predicted N-terminal signal peptide of 22 amino acids. The protein has six conserved cysteine residues, characteristic of members of the beta-defensin superfamily, as well as several potential post-translational modification sites. At the transcriptional level, HEL-75 was expressed in the epididymis and lung, but only in the epididymis at the translational level. Immunofluorescent staining showed that HEL-75 protein bound spermatozoa in the epididymis. RHEL-75 protein could kill Escherichia coli in vitro in a dose- and time-dependent fashion. However, no effect was observed on sperm motility nor fertilization when spermatozoa were blocked with anti-rHEL-75 polyclonal serum.

CONCLUSION

HEL-75 is a new beta-defensin expressed in the epididymis and on sperm; it may play an important role in host defense.