Three-dimensional structure of seminiferous tubules in the Syrian hamster.

The hamster is useful for the study of male reproductive biology. However, unlike in the mouse and rat, the gross structure of seminiferous tubules in the hamster is largely unknown. The aim of the present study was to clarify the precise 3-dimensional (3D) structure of seminiferous tubules in hamsters. We reconstructed all seminiferous tubules in 3 and 1 testes from 0-day (P0) and 10-week (adult) Syrian hamsters, respectively, using serial paraffin sections and high-performance 3D reconstruction software. In P0 hamsters, the average numbers of seminiferous tubules, terminating points, branching points, and blind ends per testis were 9.0, 89.7, 93.0, and 0.7, respectively. There were two types of tubules: shorter and dominant ones. The dominant tubules, 2-4 in number per testis and accounting for 86% of the total tubule length, had many terminating and branching points and appeared to be derived from the anastomosis of many shorter tubules. In an adult hamster, there were 11 seminiferous tubules with a total length of 22 m, 98 terminating points, 88 branching points, and 2 blind ends per testis. Three of the 11 tubules were dominant ones, accounting for 83% of the total length, and occupied the testis from the surface over the circumference to the center, while the others were short and occupied only one side of the testis. The amplitude and direction of the curves of tubules were random, and there were no funnel-shaped networks of tubules present, in contrast to the mouse testis. The present study revealed the 3D structure of seminiferous tubules in developing and adult Syrian hamsters, which is different from that in mice and rats.

Genome-wide association study of semen volume, sperm concentration, testis size, and plasma inhibin B levels.

Semen quality is affected by environmental factors, endocrine function abnormalities, and genetic factors. A GWAS recently identified ERBB4 at 2q34 as a genetic locus associated with sperm motility. However, GWASs for human semen volume and sperm concentration have not been conducted. In addition, testis size also reportedly correlates with semen quality, and it is important to identify genes that affect testis size. Reproductive hormones also play an important role in spermatogenesis. To date, genetic loci associated with plasma testosterone, sex hormone-binding globulin (SHBG), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) levels have been identified using GWASs. However, GWASs have not identified any relevant loci for plasma inhibin B levels. We conducted a two-stage GWAS using 811 Japanese men in a discovery stage followed by a replication stage using an additional 721 Japanese men. The results of the discovery and replication stages were combined into a meta-analysis. After setting a suggestive significance threshold for P values < 5 × 10-6　in the discovery stage, we identified ten regions with SNPs (semen volume: one, sperm concentration: three, testes size: two, and inhibin B: four). We selected only the most significant SNP in each region for replication genotyping. Combined discovery and replication results in the meta-analysis showed that the locus 12q21.31 associated with plasma inhibin B levels (rs11116724) had the most significant association (P = 5.7 × 10-8). The LRRIQ1 and TSPAN19 genes are located in the 12q21.31 region. This study provides new susceptibility variants that contribute to plasma inhibin B levels.

Genome-wide association study identifies ERBB4 on 2q34 as a novel locus associated with sperm motility in Japanese men.

BACKGROUND: The decrease in sperm motility has a potent influence on fertilisation. Sperm motility, represented as the percentage of motile sperm in ejaculated sperms, is influenced by lifestyle habits or environmental factors and by inherited factors. However, genetic factors contributing to individual differences in sperm motility remain unclear. To identify genetic factors that influence human sperm motility, we performed a genome-wide association study (GWAS) of sperm motility. METHODS: A two-stage GWAS was conducted using 811 Japanese men in a discovery stage, followed by a replication study using an additional 779 Japanese men. RESULTS: In the two-staged GWAS, a single nucleotide polymorphism rs3791686 in the intron of gene for erb-b2 receptor tyrosine kinase 4 (ERBB4) on chromosome 2q34 was identified as a novel locus for sperm motility, as evident from the discovery and replication results using meta-analysis (ß=-4.01, combined P=5.40×10-9). CONCLUSIONS: Together with the previous evidence that Sertoli cell-specific Erbb4-knockout mice display an impaired ability to produce motile sperm, this finding provides the first genetic evidence for further investigation of the genome-wide significant association at the ERBB4 locus in larger studies across diverse human populations.

Association of TUSC1 and DPF3 gene polymorphisms with male infertility.

PURPOSE: Recently, genome-wide association studies of a Hutterite population in the USA revealed that five single nucleotide polymorphisms (SNPs) with a significant association with sperm quality and/or function in ethnically diverse men from Chicago were significantly correlated with family size. Of these, three SNPs (rs7867029, rs7174015, and rs12870438) were found to be significantly associated with the risk of azoospermia and/or oligozoospermia in a Japanese population. In this study, we investigated whether the rs10966811 (located in an intergenic region between the TUSC1 and IZUMO3 genes) and rs10129954 (located in the DPF3 gene) SNPs, previously related to family size, are associated with male infertility. In addition, we performed association analysis between rs12348 in TUSC1 and rs2772579 in IZUMO3 and male infertility. METHODS: We genotyped 145 patients with infertility (including 83 patients with azoospermia and 62 with oligozoospermia) and 713 fertile controls by PCR-RFLP technique for polymorphism. Because rs10966811 has no restriction sites, the SNP rs12376894 with strong linkage disequilibrium was selected as an alternative to rs10966811. RESULTS: There was a statistically significant association between rs12376894 proxy SNP of rs10966811 and oligozoospermia. Also, a statistically significant association between rs10129954 and azoospermia, and oligozoospermia was observed. When we assessed the relationship between rs12348 in TUSC1 and rs2772579 in IZUMO3 and male infertility traits, we found that rs12348 in TUSC1 was significantly associated with azoospermia and oligozoospermia, but rs2772579 in IZUMO3 was not associated with male infertility. CONCLUSION: We found that the polymorphisms in TUSC1 and DPF3 displayed strong associations with male infertility.

A replication study of a candidate locus for follicle-stimulating hormone levels and association analysis for semen quality traits in Japanese men.

In men, follicle-stimulating hormone (FSH) acts on the seminiferous tubules and enhances spermatogenesis. Recently, a candidate locus (rs2414095) for FSH levels was identified by a genome-wide association study (GWAS) in Chinese men. The rs2414095 single-nucleotide polymorphism (SNP) is found on the third intron of the cytochrome P450, family 19, subfamily A, peptide 1 (CYP19A1) gene encoding an aromatase. In the present study, we performed a replication study in 1687 Japanese men (901 from cohort 1 and 786 from cohort 2) to assess whether this SNP is associated with circulating FSH levels. Furthermore, we investigated whether the rs2414095 SNP is correlated with semen quality traits in 2015 Japanese men (1224 from cohort 1 and 791 from cohort 2). The rs2414095 SNP was significantly associated with circulating FSH levels (ßSTD=0.15, P=9.7 × 10-5), sperm concentration (ßSTD=0.073, P=0.032) and total sperm number (TSN) (ßSTD=0.074, P=0.027) in a combined analysis of the two Japanese male cohorts. We successfully replicated, in Japanese men, the results of the previous GWAS for the rs2414095 SNP in Chinese men, and found that the rs2414095 SNP was related with sperm production.

An association study of four candidate loci for human male fertility traits with male infertility.

STUDY QUESTION: Are the four candidate loci (rs7867029, rs7174015, rs12870438 and rs724078) for human male fertility traits, identified in a genome-wide association study (GWAS) of a Hutterite population in the USA, associated with male infertility in a Japanese population? SUMMARY ANSWER: rs7867029, rs7174015 and rs12870438 are significantly associated with the risk of male infertility in a Japanese population. WHAT IS KNOWN ALREADY: Recently, a GWAS of a Hutterite population in the USA revealed that 41 single-nucleotide polymorphisms (SNPs) were significantly correlated with family size or birth rate. Of these, four SNPs (rs7867029, rs7174015, rs12870438 and rs724078) were found to be associated with semen parameters in ethnically diverse men from Chicago. STUDY DESIGN, SIZE, DURATION: This is a case-control association study in a total of 917 Japanese subjects, including 791 fertile men, 76 patients with azoospermia and 50 patients with oligozoospermia. PARTICIPANTS/MATERIALS, SETTING, METHODS: Azoospermia was diagnosed on the basis of semen analysis (the absence of sperm in ejaculate), serum hormone levels and physical examinations. Oligozoospermia was defined as a sperm concentration of <20 × 10(6)/ml. We excluded patients with any known cause of infertility (i.e. obstructive azoospermia, varicocele, cryptorchidism, hypogonadotropic hypogonadism, karyotype abnormalities or complete deletion of AZF a, b or c). The SNPs rs7867029, rs7174015, rs12870438 and rs724078 were genotyped using DNA from peripheral blood samples and either restriction fragment length polymorphism PCR or TaqMan probes. Genetic associations between the four SNPs and male infertility were assessed using a logistic regression analysis under three different comparative models (additive, recessive or dominant). MAIN RESULTS AND THE ROLE OF CHANCE: The genotypes of all four SNPs were in Hardy-Weinberg equilibrium in the fertile controls. The SNPs rs7867029 and rs7174015 are associated with oligozoospermia [rs7867029: odds ratio (OR) = 1.70, 95% confidence interval (CI) = 1.07-2.68, P = 0.024 (log-additive); rs7174015: OR = 6.52, 95% CI = 1.57-27.10, P = 0.0099 (dominant)] and rs12870438 is associated with azoospermia (OR = 10.90, 95% CI = 2.67-44.60, P = 0.00087 (recessive)] and oligozoospermia [OR = 8.54, 95% CI = 1.52-47.90, P = 0.015 (recessive)]. The association between rs7174015 and oligozoospermia under a dominant model and between rs12870438 and azoospermia under additive and recessive models remained after correction for multiple testing. There were no associations between rs724078 and azoospermia or oligozoospermia. LIMITATIONS, REASONS FOR CAUTION: Even though the sample size of case subjects was not very large, we found that three SNPs were associated with the risk of male infertility in a Japanese population. WIDER IMPLICATIONS OF THE FINDINGS: The three infertility-associated SNPs may be contributing to a quantitative reduction in spermatogenesis. STUDY FUNDING/COMPETING INTERESTS: This study was supported in part by the Ministry of Health and Welfare of Japan (1013201) (to T.I.), Grant-in-Aids for Scientific Research (C) (23510242) (to A.Ta.) from the Japan Society for the Promotion of Science, the European Union (BMH4-CT96-0314) (to T. I.) and the Takeda Science Foundation (to A.Ta.). None of the authors has any competing interests to declare.

Lack of replication of four candidate SNPs implicated in human male fertility traits: a large-scale population-based study.

STUDY QUESTION: Are the four candidate loci (rs7867029, rs12870438, rs7174015 and rs724078) for human male fertility traits, identified in a genome-wide association study (GWAS) of a Hutterite population in the USA, associated with semen quality traits in a Japanese population? SUMMARY ANSWER: The four single nucleotide polymorphisms (SNPs) rs7867029, rs12870438, rs7174015 and rs724078 have no association with semen parameters in a meta-analysis of two Japanese male cohorts. WHAT IS KNOWN ALREADY: Four (rs7867029, rs12870438, rs7174015 and rs724078) of the SNPs associated with family size or birth rate in the GWAS of a Hutterite population in the USA were associated with semen parameters in ethnically diverse men from Chicago, USA. STUDY DESIGN, SIZE, DURATION: This is a replication study in a total of 2015 Japanese subjects, including 791 fertile men and 1224 young men from the general population. PARTICIPANTS/MATERIALS, SETTING, METHODS: We performed a replication study in two cohorts to assess whether the SNPs rs7867029, rs12870438, rs7174015 and rs724078 are associated with sperm concentration, semen volume, total sperm numbers, total motile sperm numbers or sperm motility. The rs12870438 SNP was detected by restriction fragment length polymorphism PCR while rs7174015, rs724078 and rs7867029 SNPs were genotyped using TaqMan probes. MAIN RESULTS AND THE ROLE OF CHANCE: This study indicated that none of the four SNPs rs7867029, rs12870438, rs7174015 and rs724078 displayed a significant association with semen parameters in the meta-analysis of two Japanese male cohorts. LIMITATIONS, REASONS FOR CAUTION: Only four SNPs identified in the Hutterite GWAS were examined for associations with semen quality traits in a Japanese population. In addition, the linkage disequilibrium structures around the testing markers were different between ethnic groups. WIDER IMPLICATIONS OF THE FINDINGS: Locus mapping studies using a set of tagging SNPs across the loci will be necessary in populations with larger sample sizes in order to understand the contribution of specific genes to semen quality. STUDY FUNDING/COMPETING INTEREST S: This study was supported in part by the Ministry of Health and Welfare of Japan (1013201) (to T.I.), Grant-in-Aids for Scientific Research (C) (23510242) (to A.Ta.) from the Japan Society for the Promotion of Science, the European Union (BMH4-CT96-0314) (to T.I.), and the Takeda Science Foundation (to A.Ta.). None of the authors has any competing interests to declare.

Y chromosome gr/gr subdeletion is associated with lower semen quality in young men from the general Japanese population but not in fertile Japanese Men.

Several case-control studies have investigated whether Y chromosome haplogroups or deletions are associated with spermatogenic failure. However, the relationships between Y chromosome haplogroups or deletions and semen quality in general population have not been elucidated. In this study, we assessed relationships between Y chromosome haplogroups or deletions and semen parameters in 791 fertile Japanese men and 1221 young men from the general Japanese population. We found that the haplogroup D2 (M55 lineage) was significantly associated with lower semen parameters, especially total motile sperm count (P = 0.00051, beta = -0.097), in men from the general population but not in fertile men. In addition, we found that the gr/gr subdeletion was associated with semen quality and in particular, strongly associated with decreased sperm motility (P = 0.00041, beta = -3.14) and total motile sperm count (P = 0.00031, beta = -0.099) in men from the general population but not in fertile men. The combined analysis of fertile Japanese men and men from the general Japanese population showed that the haplogroup D2 (M55 lineage) and the gr/gr subdeletion were strongly associated with reduced sperm motility (P = 0.00056, beta = -2.71, and P = 7.7 × 10(-5), beta = -3.05, respectively) and that haplogroup O2b1 was strongly associated with elevated sperm motility (P = 0.00089, beta = 2.94). These observations add further support for the view that the gr/gr subdeletion diminishes sperm motility that consequently may result in male infertility.

Therapeutic effects of microRNA-582-5p and -3p on the inhibition of bladder cancer progression.

Many reports have indicated that the abnormal expression of microRNAs (miRNAs) is associated with the progression of disease and have identified miRNAs as attractive targets for therapeutic intervention. However, the bifunctional mechanisms of miRNA guide and passenger strands in RNA interference (RNAi) therapy have not yet been clarified. Here, we show that miRNA (miR)-582-5p and -3p, which are strongly decreased in high-grade bladder cancer clinical samples, regulate tumor progression in vitro and in vivo. Significantly, the overexpression of miR-582-5p or -3p reduced the proliferation and invasion of UM-UC-3 human bladder cancer cells. Furthermore, transurethral injections of synthetic miR-582 molecule suppressed tumor growth and metastasis in an animal model of bladder cancer. Most interestingly, our study revealed that both strands of miR-582-5p and -3p suppressed the expression of the same set of target genes such as protein geranylgeranyltransferase type I beta subunit (PGGT1B), leucine-rich repeat kinase 2 (LRRK2) and DIX domain containing 1 (DIXDC1). Knockdown of these genes using small interfering RNA (siRNA) resulted in the inhibition of cell growth and invasiveness of UM-UC-3. These findings uncover the unique regulatory pathway involving tumor suppression by both strands of a single miRNA that is a potential therapeutic target in the treatment of invasive bladder cancer.

Establishment of adult mouse Sertoli cell lines by using the starvation method.

Sertoli cells were isolated from the testes of 6-week-old mice and stable Sertoli cell lines with higher proliferation rates were subcloned after starvation of primary cultured cells. After two rounds of this subcloning, 33 subcloned lines were selected on the basis of their proliferation rates. In addition, these subclones were screened according to their phagocytic activity and the characteristics of mature Sertoli cells, such as the expression of androgen receptors (ARs) and progesterone receptors, by using western blotting and immunocytochemical analysis, in addition to their morphology and proliferation rates. After the third round of subcloning, 12 subclones were selected for the final selection using RT-PCR for identification of genes specifically expressed by various testicular cells. Three clones were selected that expressed Sertoli-cell-specific genes, i.e., stem cell factor, clusterin, AR, α-inhibin, transferrin, Wilms' tumour-1, Müllerian inhibitory substance, sex-determining region Y-box 9, FSH receptor (Fshr) and occludin; however, these clones did not express globulin transcription factor 1, steroidogenic factor or androgen-binding protein. These clones also expressed growth and differentiation factors that act on germ cells, such as leukaemia inhibitory factor, transforming growth factor ß1 and basic fibroblast growth factor 2, but did not express c-kit (specific for germ cells), LH receptor and 3ß-hydroxyl-dehydrogenase (specific for Leydig cells). Immunocytochemical data confirmed the expression of clusterin in these clones. Furthermore, the Bromodeoxyuridine incorporation assay confirmed the proliferation activity of these clones through Fshr after treatment with FSH. These clones are considered to be valuable tools for the study of Sertoli cell-specific gene expression and function.

Climatic influence on the reproductive characteristics of Japanese males.

We previously performed a survey of the sperm characteristics of the partners of pregnant women in four cities in Japan. In the present study, we analyzed the sperm characteristics of these subjects and the correlations between these sperm characteristics and climatic changes or Y chromosome haplogroups. Our results showed that more haplogroup D2a1 males than O2b1 males were born in the first half of the year (January to June), whereas more O2b1 males were born in the last half of the year (July to December) (P<0.05). This was agreed and correlated with the seasonal variations in their mean sperm concentrations. The haplogroup C, D* and D2a1 males displayed lower sperm concentrations from March to May, followed by an increase in their sperm concentrations starting in June or July, while the O2b1 males displayed higher sperm concentrations in the first half of the year followed by a sudden decrease from July to August (P<0.05). We hypothesize that the Japanese climate has different effects on the sperm characteristics and reproductive seasonality of males from different lineages; and therefore, has influenced the modern population of Japan.

Glycoconjugates recognized by peanut agglutinin lectin in the inner acellular layer of the lamina propria of seminiferous tubules in human testes showing impaired spermatogenesis.

BACKGROUND: The aim of this study was to evaluate the histochemical characteristics of the thickened inner acellular layer (IL) of the lamina propria specifically present in the human seminiferous tubules of testes showing impaired spermatogenesis. METHODS: Eighteen biopsies for the investigation of infertility and 10 orchiectomies for testicular cancer and cryptorchidism were used. Lectin staining [peanut agglutinin (PNA), Maackia amurensis (MAA), Sambuccus nigra (SNA)], PNA lectin staining with sialidase digestion, immunohistochemistry and binding assay of progesterone were performed and analysed quantitatively. RESULTS: The IL of the thickened lamina propria of the seminiferous tubules in the testes showed PNA lectin affinity and binding affinity for progesterone. Both affinities of MAA and SNA were in the IL of only fairly thickened lamina propria. Furthermore, a positive correlation was present between the thickness of the lamina propria and the accumulation of glycoconjugates showing PNA lectin affinity (r = 0.829, P < 0.001) or progesterone (r = 0.629, P < 0.001) in the IL. However, ILs show no immunoreactivities of progesterone receptor, androgen receptor or human serum albumin. Progesterone inhibited the binding affinity of PNA lectin to the IL (P < 0.001), but not the affinity to the spermatogenic cells. In addition, sialidase digestion increased the PNA affinity not in the IL but in the spermatogenic cells (P < 0.001). CONCLUSIONS: These results indicate that the IL of the thickened lamina propria always consists of glycoconjugates with PNA lectin affinity and possible binding affinity to progesterone. In addition, the glycoconjugates in the IL may be predictors of abnormal spermatogenesis in the testes of infertile patients.

Irreversible immunoexpression of matrix metalloproteinase-9 in proximal tubular epithelium of renal allografts with acute rejection.

BACKGROUND: Matrix metalloproteinase-9 (MMP-9) is the most important member of the MMP family responsible for the development and progression of various renal diseases. Our study aims to investigate the localization of MMP-9 in human renal allografts and to assess whether MMP-9 immunostaining is contributory to detect pathological change in renal biopsy. METHODS: We examined 150 renal allograft biopsies (48 baseline and 102 follow-up) from 49 transplants and analyzed the associations of clinical and histopathological data with the MMP-9 staining intensity using a semi-quantitative scoring. RESULTS: MMP-9 immunostaining in proximal tubule epithelium was negative before transplantation, but positive in biopsies with episodes, particularly with acute cellular rejection (ACR) and acute calcineurin inhibitor (CNI) toxicity. Tubulitis was the most significant association factor (p < 0.0001) with increased MMP-9 staining intensity. The expression in proximal tubules remained augmented in allografts recovered from ACR episodes, while it was disappeared or diminished in those recovered from acute CNI toxicity or ischemia/reperfusion effects. CONCLUSION: These findings suggest the necessary participation of MMP-9 in the pathogenesis of tubulitis and the subsequent stage of pathogenesis in ACR. Up-regulation of MMP-9 expression in the proximal tubule could be a new indicator of tubular injury and a predictive factor for the prognosis of renal allograft.

A change in the steroid metabolic pathway in human testes showing deteriorated spermatogenesis.

During androgen biosynthesis, the human testes normally produce only small quantities of Δ4-C21 steroids as these are products of the Δ4-pathway and healthy human testes preferentially use the Δ5-pathway. However, the Δ4-C21 steroid progesterone accumulates in the thickened lamina propria of the seminiferous tubules in testes with deteriorated spermatogenesis. The objectives of this study were to analyse the pregnenolone metabolites in testes with deteriorated spermatogenesis and to establish whether the androgen biosynthesis pathway changes in this condition. Biopsied or orchiectomised testicular samples were obtained from patients with varicocele, non-obstructive azoospermia, obstructive azoospermia, testicular cancer, and cryptorchidism. The samples were segregated into spermatogenesis related Johnsen's score groups: Low-JS (< 5.0) and High-JS (> 7.8). Higher levels of progesterone and 17α-hydroxyprogesterone were metabolised under in vitro conversion in the Low-JS testes than the High-JS testes when cell-free homogenates from each group were separately incubated with 14C-labelled pregnenolone. Nevertheless, the serum hormone levels did not differ between groups. Two novel pregnenolone metabolites 5ß-pregnan-3ß-ol-20-one and 5α-pregnan-3α, 21diol-20-one were identified from in vitro conversion in Low-JS testes and by recrystallisation. Immunohistochemistry revealed the higher ßHSD expression in the Low-JS than the High-JS testes. However, the CYP17A1 expression levels did not differ between groups. Infertile testes increase the relative ßHSD levels in their Leydig cells and synthesised testosterone from pregnenolone via the Δ4- rather than the Δ5-pathway. A new insight into a change of metabolites in Low-JS testes will be relevant to understand the mechanism of the deteriorated spermatogenesis under the normal range of testosterone level.

Clinically useful limited sampling strategy to estimate area under the concentration-time curve of once-daily tacrolimus in adult Japanese kidney transplant recipients.

BACKGROUND: An extended-release, once-daily, oral formulation of tacrolimus is currently used after kidney transplantation as a substitute for the conventional twice-daily formulation. The purpose of this study was to provide a limited sampling strategy with minimum and optimum sampling points to predict the tacrolimus area under the concentration-time curve (AUC) after administration of once-daily tacrolimus in de novo adult kidney transplant patients. METHODS: A total of 36 adult Japanese kidney transplant patients receiving once-daily tacrolimus were included: 31 were allocated to a study group to develop limited sampling strategy (LSS) model equations based on multiple stepwise linear regression analysis, and 5 were allocated to a validation group to estimate the precision of the LSS equations developed by the study group. Twelve-hour AUC (AUC0-12) was calculated by the trapezoidal rule, and the relationship between individual concentration points and AUC0-12 were determined by multiple linear regression analysis. The coefficient of determination (R2) was used to assess the goodness-of-fit of the regression models. Three error indices (mean error, mean absolute error, and root mean squared prediction error) were calculated to evaluate predictive bias, accuracy, and precision, respectively. Quality of the statistical models was compared with Akaike's information criterion (AIC). RESULTS: A four-point model using C0, C2, C4 and C6 gave the best fit to predict AUC0-12 (R2 = 0.978). In the three- and two-point models, the best fits were at time points C2, C4, and C6 (R2 = 0.973), and C2 and C6 (R2 = 0.962), respectively. All three models reliably estimated tacrolimus AUC0-12, consistent with evaluations by the three error indices and Akaike's information criterion. Practically, the two-point model with C2 and C6 was considered to be the best combination, providing a highly accurate prediction and the lowest blood sampling frequency. CONCLUSIONS: The two-point model with C2 and C6 may be valuable in reducing the burden on patients, as well as medical costs, for once-daily tacrolimus monitoring.

Semen quality of Asian men.

After the controversial report by Carlsen et al. in 1992 showing a possible decline in human semen quality over the past 50 years, many laboratories investigated their own records of semen findings that had been kept for the past decades, and a significant decrease in sperm quality was reported from some laboratories, but not others. At the beginning of the 21st century, a definitive interpretation of this issue has not yet been offered; however, it seems plausible that there are large regional differences in semen quality. Decreases in semen quality have been reported from various regions around the world, and a concurrent rise in the incidence of other reproductive problems, such as testicular cancer and genital abnormalities, has been observed in many regions. However, most of the reports showing regional differences were from Western or Western-derived countries, despite the fact that Asia is the region with the highest population on earth. Recently we undertook a cross-sectional study on fertile men in Japan to describe the current status of semen quality of Japanese men. We took confounders into consideration to allow a comparison with a previous European study. Japanese fertile men proved to have a semen quality at the level of Danish men, who were reported to have the lowest level among the men examined in the European study. This low level of sperm concentration in fertile Japanese men may result from differences in lifestyle or other environmental factors, but we cannot rule out the possibility of ethnic differences caused by different genetic variation or combination. To address this issue we need more information on the reproductive function in Asian men, who have been reported to have certain differences in reproductive characteristics from Caucasian men. This article is an attempt to review our present knowledge concerning the current status of semen quality in healthy Asian men on the basis of the limited publications from Asia. (Reprod Med Biol 2007; 6: 185-193).

Erratum: An independent validation study of three single nucleotide polymorphisms at the sex hormone-binding globulin locus for testosterone levels identified by genome-wide association studies.

[This corrects the article DOI: 10.1093/hropen/hox002.][This corrects the article DOI: 10.1093/hropen/hox002.].

An independent validation study of three single nucleotide polymorphisms at the sex hormone-binding globulin locus for testosterone levels identified by genome-wide association studies.

STUDY QUESTION: Are the single nucleotide polymorphisms (SNPs) rs2075230, rs6259 and rs727428 at the sex hormone-binding globulin (SHBG) locus, which were identified by genome-wide association studies (GWASs) for testosterone levels, associated with testosterone levels in Japanese men? SUMMARY ANSWER: The SNP rs2075230, but not rs6259 and rs727428, is significantly associated with testosterone levels in Japanese men. WHAT IS ALREADY KNOWN: Previous GWASs have revealed that rs2075230 is associated with serum testosterone levels in 3495 Chinese men and rs6259 and rs727428 are associated with serum testosterone levels in 3225 men of European ancestry. STUDY DESIGN SIZE AND DURATION: This is an independent validation study of 1687 Japanese men (901 in Cohort 1 and 786 in Cohort 2). PARTICIPANTS/MATERIALS SETTING AND METHOD: Cohort 1 (20.7 ± 1.7 years old, mean ± SD) and Cohort 2 (31.2 ± 4.8 years) included samples obtained from university students and partners of pregnant women, respectively. The three SNPs were genotyped using either TaqMan probes or restriction fragment length polymorphism PCR. Blood samples were drawn from the cubital vein of the study participants in the morning, and total testosterone and SHBG levels were measured using a time-resolved immunofluorometric assay. Association between each SNP and testosterone levels was evaluated by meta-analysis of the two Japanese male cohorts. MAIN RESULTS AND THE ROLE OF CHANCE: The age of the two cohorts was significantly different (P < 0.0001). We found that rs2075230 was significantly associated with serum testosterone levels (ß STD = 0.15, P = 7.2 × 10-6); however, rs6259 and rs727428 were not (ß STD = 0.17, P = 0.071; ß STD = 0.082, P = 0.017, respectively), after adjusting for multiple testing in a combined analysis of two Japanese male cohorts. Moreover, rs2075230, rs6259 and rs727428 were significantly associated with high SHBG levels (ß STD = 0.22, P = 3.4 × 10-12; ß STD = 0.23, P = 6.5 × 10-6 and ß STD = 0.21, P = 3.4 × 10-10, respectively). LARGE SCALE DATA: Not applicable. LIMITATIONS REASONS FOR CAUTION: This study had differences in the age and background parameters of participants compared to those observed in previous GWASs. In addition, the average age of participants in the two cohorts in our study also differed from one another. Therefore, the average testosterone levels, which decrease with age, between studies or the two cohorts were different. WIDER IMPLICATIONS OF THE FINDINGS: The three SNPs have a considerable effect on SHBG levels and hence may indirectly affect testosterone levels. STUDY FUNDING/COMPETING INTERESTS: This study was supported partly by the Ministry of Health and Welfare of Japan (1013201) (to T.I.), Grant-in-Aids for Scientific Research (C) (26462461) (to Y.S.) and (23510242) (to A.Ta.) from the Japan Society for the Promotion of Science, the European Union (BMH4-CT96-0314) (to T.I.) and the Takeda Science Foundation (to A.Ta.). There are no conflicts of interest to declare.

[Effects of endocrine disrupting chemicals on male reproductive function--epidemiological views].

Numerous medical studies have recently focused on the adverse trends in human male reproductive health including possible decline in semen quality and increasing incidences of reproductive anomalies such as testicular cancer, cryptorchidism and hypospadias, which have been reported from many counties during past decades. We have no sufficient evidence on the basis of which we could determine whether human male reproductive health is really declining and whether endocrine disrupting chemicals are responsible for this observed decline. However, Skakkebaek's group has currently proposed a hypothesis that the male reproductive problems are symptoms of one underlying entity, the testicular dysgenesis syndrome (TDS), which may be increasingly common due to adverse environmental influences. According to this hypothesis, TDS is a result of the disruption of embryonal programming and gonadal development during the fetal stage and the recent rise in the prevalence of TDS may be causally linked to endocrine disrupting chemicals affecting genetically susceptible individuals. This review aims to give a brief overview of the suspected adverse trend in human male reproductive health and current data associated with TDS.

Expression Level of Urinary MicroRNA-146a-5p Is Increased in Patients With Bladder Cancer and Decreased in Those After Transurethral Resection.

BACKGROUND: Bladder cancer is the most prevalent malignancy involving the urinary system and exhibits a markedly high recurrence rate. Therefore, reliable and noninvasive diagnostic and surveillance methods are desperately needed. PATIENTS AND METHODS: Candidate microRNAs (miRNAs) were selected from the miRNAs that were differentially expressed in bladder cancer cell lines (T24 and RT4) compared to normal ureteral epithelial tissue using miRNA-microarray analysis. The candidate miRNAs were validated by quantitative reverse transcription polymerase chain reaction assay using voided urine samples. RESULTS: We identified 3 miRNAs (miR-301b, -563, and -146a-5p) that demonstrated > 2-fold higher expression levels in cancer cell lines than in the normal ureteral epithelial tissue. Of these, only miR-146a-5p was consistently and significantly higher in urine samples from the patients with bladder cancer than in those from the normal individuals (P = .0014). The patients with high-grade tumors exhibited significantly higher urinary miR-146a-5p levels than those with low-grade tumors, and the patients with invasive tumors tended to show higher urinary miR-146a-5p levels than those with noninvasive tumors. Elevated urinary miR-146a-5p levels in patients with bladder cancer were decreased to the normal level after transurethral resection of the tumors (P = .0214). CONCLUSION: Our study suggested that urinary miR-146a-5p might be useful as a new noninvasive diagnostic marker, therapeutic target, or anticancer agent for bladder cancer, as well as for increasing our understanding of cancer biology.