Effects of cigarette smoking on semen quality, reproductive hormone levels, metabolic profile, zinc and sperm DNA fragmentation in men: results from a population-based study.

Background: Cigarette smoking seems to have a negative impact on men's reproductive health, but our knowledge of its effects on the reproductive function of Russian men is still very limited. The purpose of this study was to evaluate the effect of cigarette smoking on semen quality, including sperm DNA fragmentation, hormonal, zinc and metabolic status in young men from the general multi-ethnic Russian population (n=1,222, median age 23 years) and to find out the ethno-specific effects of smoking by comparing male groups of different ethnicity. Methods: Each participant filled out a standardized questionnaire, provided one blood and semen sample. Semen parameters, serum reproductive hormones, lipids, glucose, uric acid and seminal zinc were analyzed. Participants were classified as smokers (n=450) and non-smokers (n=772), and smokers were stratified into moderate (≤10 cigarettes/day) and heavy (>10 cigarettes/day) smokers. Results: In the entire study population, heavy smokers were characterized by a decrease in semen volume, total sperm count, sperm concentration and motility, and an increase in sperm DNA fragmentation and teratozoospermia compared with non-smokers (p<0.05). There was also a reduction in the serum and seminal zinc level as well as an impairment in metabolic health in smokers compared with non-smokers (p<0.05). No significant differences between smokers and non-smokers were found for serum levels of LH, FSH, inhibin B, testosterone and estradiol. In the second part of our study, the most numerous ethnic groups of Slavs (n=654), Buryats (n=191), and Yakuts (n=125) were selected from the entire study population. Among three ethnic groups, the smoking intensity was higher in Slavs than in Buryats or Yakuts suggesting a greater tobacco addiction in Slavs than in Asians. A decrease in semen parameters and seminal zinc levels, and an increase in sperm DNA fragmentation and teratozoospermia was observed only in smoking Slavs (p<0.05); moderate decrease in testosterone and increase in triglyceride levels were revealed in smoking Yakuts (p<0.05), but no significant changes were detected in smoking Buryats. Conclusion: We concluded that cigarette smoking has an ethno-specific effect on male reproductive function, probably due to the different activity of the seminal antioxidant system, which is yet to be elucidated.

Age-Related Changes in Sperm Morphology and Analysis of Multiple Sperm Defects.

BACKGROUND: Analysis of sperm morphology defects (amorphous heads, abnormal acrosome, etc.) is useful for estimating the efficiency of spermiogenesis and sperm maturation. An advanced paternal age (more than 40 years) is associated with decreasing sperm count and reduced motility; however, there is little information on the effect of aging relating to sperm morphological defects. Moreover, searching for stable combinations of certain morphological defects in the same sperm can be useful for better understanding spermiogenesis. The aim of the study was to investigate age-related changes in sperm morphology and the prevalence of certain combinations of sperm morphological defects in men from the general population. METHODS: Sperm morphology was assessed in 1266 volunteers from the Russian urban general population in different age groups (18-19, 20-24, 25-29, 30-34, 35-40, and over 40 years old). Two hundred sperm were evaluated from each semen sample (about 250 thousand spermatozoa in total). Sperm defects were classified according to the WHO laboratory manual (WHO, 2010). The total percentage of each sperm defect and the frequency of different combinations of sperm morphological anomalies for each age group were counted. Additionally, a similar analysis was performed for the groups of normospermia and pathozoospermia. RESULTS: The frequency of coiled and short sperm tails increased in men over 40 years old compared to younger subjects; however, aging did not affect the percentage of morphologically normal sperm. It was shown that the combination of a misshaped head (amorphous, pyriform, and elongated) with a postacrosomal vacuole, acrosome defect, excess residual cytoplasm, or any anomaly of the midpiece or tail in the same spermatozoon were not random combinations of independent solitary defects. The increased frequency of combinations of coiled tails with amorphous, elongated, or vacuolated heads was observed in men older than 40 years. Sperm morphological defects, such as severely deformed heads (pyriform, elongated, and round) were more common in men with pathozoospermia compared to normospermic subjects. CONCLUSIONS: An age-related impairment in sperm morphology was found. Stable combinations of head defects with anomalies in the acrosome, midpiece or tail suggest that these defects may be the result of a general violation in the morphogenetic mechanism.

Androgen Receptor Gene CAG Repeat Length Varies and Affects Semen Quality in an Ethnic-Specific Fashion in Young Men from Russia.

Male infertility is a multi-factorial and multi-genetic disorder, and the prevalence of male infertility in the world is estimated at 5-35%. The search for the causes of male infertility allowed for identifying a number of genetic factors including a single X-linked gene of the androgen receptor (AR), and some of its alleles are assumed to negatively affect male fertility. Our aim was (1) to study the variability of the length of CAG repeats of the AR gene and possible associations in the AR CAG genetic variants with semen quality and reproductive hormone levels in a population-based cohort of men and (2) to estimate distributions of AR CAG repeat alleles and associations with semen parameters in different ethnic subgroups. The cohort of 1324 young male volunteers of different ethnicities (median age 23.0 years) was recruited from the general population of five cities of the Russian Federation, regardless of their fertility status. Semen quality (sperm concentration, motility and morphology), reproductive hormone levels (testosterone, estradiol, LH, FSH and inhibin B) and trinucleotide (CAG) n repeat polymorphism in exon 1 of the AR gene were evaluated. The semen samples were analyzed according to the WHO laboratory manual (WHO, 2010), serum hormones were measured by enzyme immunoassay, and the AR CAG repeat length was analyzed by direct sequencing of leukocyte DNA. The median AR CAG repeat length in men of our multi-ethnic population was 23 (range 6-39). In the entire study population, a significant difference (p ≤ 0.05) was found in the frequency distribution and the mean values for the CAG repeat length between the groups with normal (23.2 ± 3.3) and impaired semen quality (23.9 ± 3.2). Additionally, we demonstrated that the total sperm count, sperm concentration, progressive motility and normal morphology were lower in the category of long CAG repeats (CAG ≥ 25) compared with those in the category of short CAG repeats (CAG ≤ 19); however, hormonal parameters did not differ between the long and short CAG categories, with the exception of estradiol. Significant differences were observed in the AR CAG repeat length between the most common ethnic cohorts of Slavs (Caucasians), Buryats (Asians), and Yakuts (Asians). The Buryats and Yakuts had a higher number of CAG repeats than the Slavs (medians: Slavs-23; Buryats-24; Yakuts-25). The range of alleles differed among ethnicities, with the Slavs having the largest range (7-36 repeats, 24 alleles total), the Yakuts having the smallest range (18-32 repeats, 14 alleles total) and the Buryats having the middle range (11-39 repeats, 20 alleles total). The longer CAG repeats were associated with an impaired semen quality within the Slavic (CAG ≥ 25) and Buryat (CAG ≥ 28) groups, but this effect was not found in Yakuts. Hormonal parameters did not differ between the three CAG repeat categories in men of all ethnic groups. This is the largest Russian study of the distribution of AR CAG repeats and the search for association between length of AR CAG repeat tract and impaired spermatogenesis in men from the general population. Our results confirmed the association of longer CAG repeats with a risk of impaired semen quality, but this association can be modified by ethnic origin. Identification of the number of AR CAG repeats can be an effective tool to assess the risk of male subfertility and the control of androgen hormone therapy of reproductive diseases.

Impaired semen quality, an increase of sperm morphological defects and DNA fragmentation associated with environmental pollution in urban population of young men from Western Siberia, Russia.

Poor sperm morphology and an elevated DNA fragmentation level are considered to be related to spermiogenesis malfunctions as a result of genetic mutations and effects of environmental factors, including industrial pollution. Standardized cross-sectional population studies of sperm morphology defects and sperm DNA fragmentation, especially in regions with increased environmental pollution may be helpful to investigate an influence of industrial pollution and other population-related factors on spermiogenesis process. The aim of present study was to estimate an influence industrial pollution on sperm morphogenesis and sperm DNA fragmentation in men from the general population of the Western Siberia. The Novosibirsk and Kemerovo cities are located to same climatic conditions in Western Siberia but the Kemerovo city is characterized by increased environmental pollution especially by particulate matter (PM). The male volunteers living in Novosibirsk (n = 278) and Kemerovo (n = 258) were enrolled. Percentages of sperm morphological defects are counted after staining native ejaculate smears by Diff-Quick kits. DNA fragmentation was estimated by a SCSA technique. The residents of Kemerovo were characterized by lowered sperm count and sperm motility, elevated DNA fragmentation, poor sperm morphology and increased incidence of morphological effects of head (pyriform, elongated, round, abnormal acrosome and vacuolated chromatine), asymmetrical neck insertion and excess residual cytoplasm. Moreover, elevated DNA fragmentation was associated with lowered sperm count, sperm motility and increased percentages of several sperm morphology defects, with the place of residence affecting the relationships between conventional semen parameters, sperm morphology and DNA fragmentations. Our study suggests that excessive sperm head elongation and impaired acrosome formation can contribute to sperm morphology deterioration in men from polluted areas. Regional features in the relationships between sperm morphology, sperm count and DNA fragmentation were shown, suggesting an importance of studying sperm morphology pattern in men from different regions.

Impact of seminal and serum zinc on semen quality and hormonal status: A population-based cohort study of Russian young men.

BACKGROUND: Trace elements are important factors in human reproductive health. Among them, special attention is paid to zinc, which is an essential trace element and is necessary for the normal functioning of the male reproductive system and the process of spermatogenesis. The aim of the study was to investigate the association between seminal and serum zinc concentrations and semen quality and reproductive hormone levels in population of Russian young men. METHODS: The study population consisted of 626 young Russian men (median age 22.5 years), recruited from the general population, regardless of their fertility status. Each participant provided semen and blood sample, information about his lifestyle and ethnicity. Semen quality (sperm concentration, motility and morphology), reproductive hormone levels (testosterone, estradiol, LH, FSH and inhibin B), and serum and seminal zinc concentrations were evaluated. The semen samples were analyzed according to the WHO laboratory manual (WHO, 2010). Serum hormones were measured by enzyme immunoassay, zinc concentrations were determined using spectrophotometry and direct colorimetry without deproteinization. RESULTS: Zinc was present in the seminal plasma in a significantly higher concentration than in the blood serum (median serum Zn concentration was 23.6 µmol/L vs seminal Zn concentration 1571.8 µmol/L). The seminal zinc concentration was positively related to the total sperm count, sperm concentration, progressive motility and normal morphology (Spearman's test: 0.221; 0.286; 0.269; 0.183, respectively, p < 0.001), while the serum Zn concentration was negatively related to serum testosterone and estradiol levels (r = -0.249 and r = -0.096, respectively, p < 0.001-0.05). It was found that the seminal Zn content in men with normal semen quality was higher compared to men with lowered semen quality (means: 6.37 and 5.03 µmol/ejaculate, respectively, p < 0.001). Similarly, the semen volume, total sperm count, sperm concentration, progressive motility, normal morphology and the serum testosterone level in men with the seminal Zn deficiency were lower than in men with the normal seminal Zn content. CONCLUSION: Based on the results of our population-based study, seminal Zn levels were closely associated with semen parameters in young men, so Zn deficiency may be an important risk factor for lowered semen quality. Seminal Zn determinations should be considered as a useful tool in addition to other parameters in assessing male fertility.

A Catalog of Human Genes Associated With Pathozoospermia and Functional Characteristics of These Genes.

Genetic causes of the global decline in male fertility are among the hot spots of scientific research in reproductive genetics. The most common way to evaluate male fertility in clinical trials is to determine semen quality. Lower semen quality is very often accompanied by subfertility or infertility, occurs in many diseases and can be caused by many factors, including genetic ones. The following forms of lowered semen quality (pathozoospermia) are known: azoospermia, oligozoospermia, asthenozoospermia, teratozoospermia, and some combined forms. To systematize information about the genetic basis of impaired spermatogenesis, we created a catalog of human genes associated with lowered semen quality (HGAPat) and analyzed their functional characteristics. The catalog comprises data on 126 human genes. Each entry of the catalog describes an association between an allelic variant of the gene and a particular form of lowered semen quality, extracted from the experimental study. Most genes included into the catalog are located on autosomes and are associated with such pathologies as non-obstructive azoospermia, oligozoospermia or asthenozoospermia. Slightly less than half of the included genes (43%) are expressed in the testes in a tissue-specific manner. Functional annotation of genes from the catalog showed that spermatogenic failure can be associated with mutations in genes that control biological processes essential for spermiogenesis (regulating DNA metabolism, cell division, formation of cellular structures, which provide cell movement) as well as with mutations in genes that control cellular responses to unfavorable conditions (stress factors, including oxidative stress and exposure to toxins).

Regional and ethnic differences in semen quality and reproductive hormones in Russia: A Siberian population-based cohort study of young men.

BACKGROUND: This is the first large-scale Russian study describing semen quality and reproductive hormone levels among young men. OBJECTIVES: The aim of the study was to compare semen quality and reproductive hormone levels in young men of four cities and three ethnic groups living in the Siberian region of Russia and to find out ethnic or environmental reasons for regional differences. MATERIALS AND METHODS: The study population consisted of 1291 young men from Novosibirsk, Kemerovo, Ulan-Ude, and Yakutsk, including 1013 men of three most numerous ethnic groups: Slavs, Buryats, and Yakuts. Each participant provided one sperm and blood sample, information about lifestyle and ethnicity. Anthropometric parameters, semen quality and reproductive hormone levels, were evaluated. RESULTS: Significant regional and ethnic differences were detected for semen and reproductive hormone parameters. Median sperm concentrations in Novosibirsk, Kemerovo, Ulan-Ude, and Yakutsk were 54.6, 39.9, 34.7, 33.1 × 106 /ml; total sperm counts-202.5, 138.7, 97.9, 93.4 × 106 ; percentages of morphologically normal spermatozoa-7.8%, 6.5%, 6.3%, 5.0%, respectively. Median sperm concentrations in Slavs, Buryats, and Yakuts were 43.7, 37.0, 30.6 × 106 /ml; total sperm counts-150.0, 102.3 and 74.8 × 106 ; percentages of morphologically normal spermatozoa-6.8%, 6.8%, 4.8%, respectively. DISCUSSION: The young men in Novosibirsk and Kemerovo, populated by Slavs, had a higher semen quality compared to Ulan-Ude and Yakutsk, populated by Buryats and Yakuts, apparently due to the higher testicular function in Slavic compared to Asian ethnicity. Impaired spermatogenesis in young men in Kemerovo compared to Novosibirsk, located in the same climatic zone and having a socio-cultural and ethnic identity, may be due to the influence of a polluted environment. CONCLUSION: The findings suggest that ethnic composition and environment may be responsible for regional differences in semen and reproductive hormone parameters.

Gastric Cancer in BRCA1 Germline Mutation Carriers: Results of Endoscopic Screening and Molecular Analysis of Tumor Tissues.

INTRODUCTION: There is some evidence suggesting a link between BRCA1/2 germline mutations and increased risk of gastric cancer. METHODS: Endoscopic screening for stomach malignancies was performed in 120 BRCA1 mutation carriers in order to evaluate the probability of detecting the tumor disease. RESULTS: No instances of gastric cancer were revealed at the first visit. The analysis of atrophic changes performed by OLGA (Operative Link for Gastritis Assessment) criteria revealed that OLGA stages I-IV alterations were observed in 26 of 41 (63%) subjects aged >50 years as compared to 29 of 79 (37%) in younger subjects (p = 0.007, χ2 test). One BRCA1 mutation carrier developed gastric cancer 4 years after the first visit for endoscopic examination. We performed next-generation sequencing analysis for this tumor and additional 4 archival gastric cancers obtained from BRCA1/2 mutation carriers. Somatic loss of the remaining BRCA1/2 allele was observed in 3 out of 5 tumors analyzed; all of these carcinomas, but none of the malignancies with the retained BRCA1/2 copy, showed chromosomal instability. CONCLUSION: Taken together, these data justify further studies on the relationships between the BRCA1/2 and gastric cancer.

Disruptive natural selection by male reproductive potential prevents underexpression of protein-coding genes on the human Y chromosome as a self-domestication syndrome.

BACKGROUND: In population ecology, the concept of reproductive potential denotes the most vital indicator of chances to produce and sustain a healthy descendant until his/her reproductive maturity under the best conditions. This concept links quality of life and longevity of an individual with disease susceptibilities encoded by his/her genome. Female reproductive potential has been investigated deeply, widely, and comprehensively in the past, but the male one has not received an equal amount of attention. Therefore, here we focused on the human Y chromosome and found candidate single-nucleotide polymorphism (SNP) markers of male reproductive potential. RESULTS: Examining in silico (i.e., using our earlier created Web-service SNP_TATA_Z-tester) all 1206 unannotated SNPs within 70 bp proximal promoters of all 63 Y-linked genes, we found 261 possible male-reproductive-potential SNP markers that can significantly alter the binding affinity of TATA-binding protein (TBP) for these promoters. Among them, there are candidate SNP markers of spermatogenesis disorders (e.g., rs1402972626), pediatric cancer (e.g., rs1483581212) as well as male anxiety damaging family relationships and mother's and children's health (e.g., rs187456378). First of all, we selectively verified in vitro both absolute and relative values of the analyzed TBP-promoter affinity, whose Pearson's coefficients of correlation between predicted and measured values were r = 0.84 (significance p <  0.025) and r = 0.98 (p <  0.025), respectively. Next, we found that there are twofold fewer candidate SNP markers decreasing TBP-promoter affinity relative to those increasing it, whereas in the genome-wide norm, SNP-induced damage to TBP-promoter complexes is fourfold more frequent than SNP-induced improvement (p <  0.05, binomial distribution). This means natural selection against underexpression of these genes. Meanwhile, the numbers of candidate SNP markers of an increase and decrease in male reproductive potential were indistinguishably equal to each other (p <  0.05) as if male self-domestication could have happened, with its experimentally known disruptive natural selection. Because there is still not enough scientific evidence that this could have happened, we discuss the human diseases associated with candidate SNP markers of male reproductive potential that may correspond to domestication-related disorders in pets. CONCLUSIONS: Overall, our findings seem to support a self-domestication syndrome with disruptive natural selection by male reproductive potential preventing Y-linked underexpression of a protein.

Study of Semen Quality, Reproductive Hormone Levels, and Lipid Levels in Men From Arkhangelsk, a City in North of European Russia.

Male populations in the European North of Russia have not previously been investigated for semen quality. The aim of this study was to evaluate semen parameters, reproductive hormone levels, and lipid levels in volunteers from the general urban population of the European North of Russia, to compare the data published for men from the neighboring Northern or Eastern European countries, and to evaluate associations between sperm quality and serum hormonal and lipid levels. Ninety-nine volunteers aged 23-63 years residing in the city of Archangelsk were enrolled in the study. All men had blood samples drawn and completed a questionnaire concerning their health status and lifestyle; 90 men delivered semen samples. The medians for semen volume, sperm concentration, progressive motility, and normal morphology were 3.0 ml, 42.12 million/ml, 43.8%, and 6.5%, respectively. Sperm parameters below normal threshold values were found in 38.9% of participants. It seems that the sperm quality in our study group was slightly worse than in men from Finland, Norway, Sweden, or Estonia, but very similar to that in men from Denmark or Poland. The significant negative correlations of luteinizing hormone levels and positive correlations of inhibin B levels with sperm concentration and progressive motility were revealed. Higher levels of luteinizing hormone and lower levels of inhibin B were found in participants with impaired compared to normal sperm quality. No reliable links were found between serum total cholesterol, triglyceride, high and low-density lipoprotein cholesterol, and semen parameters.

Natural Selection Equally Supports the Human Tendencies in Subordination and Domination: A Genome-Wide Study With in silico Confirmation and in vivo Validation in Mice.

We proposed the following heuristic decision-making rule: "IF {an excess of a protein relating to the nervous system is an experimentally known physiological marker of low pain sensitivity, fast postinjury recovery, or aggressive, risk/novelty-seeking, anesthetic-like, or similar agonistic-intolerant behavior} AND IF {a single nucleotide polymorphism (SNP) causes overexpression of the gene encoding this protein} THEN {this SNP can be a SNP marker of the tendency in dominance} WHILE {underexpression corresponds to subordination} AND vice versa." Using this decision-making rule, we analyzed 231 human genes of neuropeptidergic, non-neuropeptidergic, and neurotrophinergic systems that encode neurotrophic and growth factors, interleukins, neurotransmitters, receptors, transporters, and enzymes. These proteins are known as key factors of human social behavior. We analyzed all the 5,052 SNPs within the 70 bp promoter region upstream of the position where the protein-coding transcript starts, which were retrieved from databases Ensembl and dbSNP using our previously created public Web service SNP_TATA_Comparator (http://beehive.bionet.nsc.ru/cgi-bin/mgs/tatascan/start.pl). This definition of the promoter region includes all TATA-binding protein (TBP)-binding sites. A total of 556 and 552 candidate SNP markers contributing to the dominance and the subordination, respectively, were uncovered. On this basis, we determined that 231 human genes under study are subject to natural selection against underexpression (significance p < 0.0005), which equally supports the human tendencies in domination and subordination such as the norm of a reaction (plasticity) of the human social hierarchy. These findings explain vertical transmission of domination and subordination traits previously observed in rodent models. Thus, the results of this study equally support both sides of the century-old unsettled scientific debate on whether both aggressiveness and the social hierarchy among humans are inherited (as suggested by Freud and Lorenz) or are due to non-genetic social education, when the children are influenced by older individuals across generations (as proposed by Berkowitz and Fromm).