Background: Ambient air pollution has been associated with a variety of reproductive disorders. However, a limited amount of research has been conducted to examine the association between air pollution and male reproductive outcomes, specifically semen quality. Aim: The present study was designed to address the hypothesis that exposure to fluctuating levels of specific air pollutants adversely affects sperm parameters and the level of reproductive hormones. Subjects and methods: The study population consisted of 327 men who were attending an infertility clinic in Łodź, Poland for diagnostic purposes and who had normal semen concentration of 15–300 mln/ml. All participants were interviewed and provided a semen sample. Air quality data were obtained from AirBase database. Results: The statistically significant association was observed between abnormalities in sperm morphology and exposure to all examined air pollutants (PM₁₀, PM_2.5, SO₂, NO_X, CO). Exposure to air pollutants (PM₁₀, PM_2.5, CO, NO_x) was also negatively associated with the level of testosterone. Additional exposure to PM_2.5, PM₁₀ increase the percentage of cells with immature chromatin (HDS). Conclusions: The present study provides suggestive evidence of an association between ambient air pollution and sperm quality. Further research is needed to explore this association in more detail. Individual precise exposure assessment would be needed for more detailed risk characterization.

The present study was designed to investigate whether environmental exposure to pyrethroids was associated with sperm DNA damage. Between January 2008 and April 2011 286 men under 45 years of age with a normal sperm concentration of 15–300 10⁶/ml [WHO 2010] were recruited from an infertility clinic in Lodz, Poland. Participants were interviewed and provided urine, saliva, and semen samples. The pyrethroids metabolites: 3-phenoxybenzoic acid (3PBA), cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (CDCCA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (TDCCA), and cis-2,2-dibromovinyl-2,2-dimethylcyclopropane-carboxylic acid (DBCA) were analyzed in the urine using a validated gas chromatography ion-tap mass spectrometry method. Sperm DNA damage was assessed using a flow cytometry based on sperm chromatin structure assay (SCSA). A positive association was observed between CDCCA >50th percentile and the percentage of medium DNA fragmentation index (M DFI) and percentage of immature sperms (HDS) (p = 0.04, p = 0.04 respectively). The level of 3PBA >50th percentile in urine was positively related to the percentage of high DNA fragmentation index (H DFI) (p = 0.03). The TDCCA, DBCA levels, and the sum of pyrethroid metabolites were not associated with any sperm DNA damage measures. Our results suggest that environmental pyrethroid exposure may affect sperm DNA damage measures index indicated the reproductive effects of pyrethroid exposure on adult men. In view of the importance of human reproductive health and the widespread usage of pyrethroids, it is important to further investigate these correlations.

The relationship between exposure to lifestyle factors and adverse effects on human reproductive health is debated in the scientific literature and these controversies have increased public and regulatory attention. The aim of the study was to examine the association between modifiable lifestyle factors and main semen parameters, sperm morphology, and sperm chromatin structure. The study population consisted of 344 men who were attending an infertility clinic for diagnostic purposes with normal semen concentration of 20–300 M/ml or with slight oligozoospermia (semen total concentration of 15–20 M/ml) [WHO 1999]. Participants were interviewed and provided semen samples. The interview included questions about demographics, socio-economic status, medical history, lifestyle factors (consumption of alcohol, tobacco, coffee intake, cell phone and sauna usage), and physical activity. The results of the study suggest that lifestyle factors may affect semen quality. A negative association was found between increased body mass index (BMI) and semen volume (p = 0.03). Leisure time activity was positively associated with sperm concentration (p = 0.04) and coffee drinking with the percentage of motile sperm cells, and the percentage of sperm head and neck abnormalities (p = 0.01, p = 0.05, and p = 0.03, respectively). Drinking red wine 1–3 times per week was negatively related to sperm neck abnormalities (p = 0.01). Additionally, using a cell phone more than 10 years decreased the percentage of motile sperm cells (p = 0.02). Men who wore boxer shorts had a lower percentage of sperm neck abnormalities (p = 0.002) and percentage of sperm with DNA damage (p = 0.02). These findings may have important implications for semen quality and lifestyle.

Diet is a complex exposure variable, which calls for multiple approaches to examine the relationship between diet and disease risk. To address these issues, several authors have recently proposed studying overall dietary patterns by considering how foods and nutrients are consumed in combinations. The aim of the study was to investigate the associations between dietary patterns, semen quality parameters, and the level of reproductive hormones. The study population consisted of 336 men who attended the infertility clinic for diagnostic purposes and who had normal semen concentration of 20 to 300 mln/ml or slight oligozoospermia (semen concentration of 15-20 mln/ml). Participants were interviewed, and a semen sample was provided by them. Diet was assessed via food frequency questionnaire, and dietary patterns were identified by factor analysis. Men were classified into three groups according to scores of each dietary pattern: Western, Mixed, or Prudent. A positive association was observed between sperm concentration and Prudent dietary pattern, and level of testosterone and Prudent dietary pattern (p = .05, p = .03, respectively). Additionally, Prudent dietary pattern was identified to decrease the DNA fragmentation index (p = .05). The results were adjusted for sexual abstinence, age, smoking, past diseases, and alcohol consumption. Higher consumption of a Prudent dietary pattern was associated with higher sperm concentration and higher level of testosterone. Sperm chromatin structure was inversely related to higher consumption of a Prudent dietary pattern. Further research is needed to confirm these findings and extend these results to other populations.

Reproductive failure in humans is a very important social and economic problem, because nowadays women decide to conceive later in life and delay motherhood. Unfortunately, with increasing age they have less chance for natural fertilization and maintenance of pregnancy. Many of them need assisted reproductive technology. Approximately 10% of women after in vitro fertilization-embryo transfers experience recurrent implantation failure (RIF). Multiple factors may contribute to RIF, including oocyte and sperm quality, parental chromosomal anomalies, genetic or metabolic abnormalities of the embryo, poor uterine receptivity, immunological disturbances in the implantation site, and some gynecologic pathologies such as endometriosis, uterine fibroids, hydrosalpinx and endometrial polyps. Moreover, the procedure of in vitro fertilization itself could adversely influence the implantation. Nowadays, many studies are focused on the role of natural killer (NK) cells in normal and pathologic pregnancy because NK cells constitute the dominant cell population in the endometrium and they come in close contact with the allogeneic extravillous trophoblast cells in early pregnancy decidua. The majority of these cells are of CD56^bright phenotype. These cells can express killer immunoglobulin-like receptors (KIRs), which, upon recognition of HLA class I molecules (HLA-C and HLA-G) on trophoblasts, may either stimulate or inhibit NK cells to produce soluble factors, and display low cytotoxicity necessary for maintenance of the allogeneic embryo and fetus in the next steps of pregnancy. Moreover, some members of the leukocyte immunoglobulin-like receptor (LILR) family, also named ILT (immunoglobulin-like transcript), are present in the human placenta. LILRB1 (ILT2) was described mainly on stromal cells, while LILRB2 (ILT4), in addition to stromal cells, was also found around vessels in the smooth muscle layer. In this review we focus on the possible role of polymorphism of KIR, LILRB and their ligands (HLA-C, HLA-G) in susceptibility to recurrent implantation failure, which could serve as diagnostic biomarkers of this disease.