Sperm telomere length as a parameter of sperm quality in normozoospermic men.

STUDY QUESTION: Could sperm telomere length (STL) represent a novel parameter and biomarker of sperm quality? SUMMARY ANSWER: STL is associated with standard semen quality parameters and, more importantly, it is significantly associated with levels of DNA fragmentation and sperm protamination. WHAT IS KNOWN ALREADY: Telomeres are fundamental for genome integrity. Recent studies have demonstrated that STL increases with age and men with oligozoospermia have shorter sperm telomeres than normozoospermic men. STUDY DESIGN, SIZE, DURATION: Cohort study conducted from September 2014 to June 2015 on 100 subjects with normal standard semen parameters. PARTICIPANTS/MATERIALS, SETTING, METHODS: STL was measured indirectly by quantitative polymerase chain reaction using telomere/single-copy gene ratio, sperm DNA fragmentation by terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling assay and protamination by aniline blue staining. Data were analyzed for determining the relationships between STL, standard semen parameters and DNA fragmentation and protamination. MAIN RESULTS AND THE ROLE OF CHANCE: Among standard semen parameters, STL was positively associated with progressive motility (P = 0.004) and vitality (P = 0.007). STL was significantly and negatively associated with sperm DNA fragmentation (P = 0.001) and significantly and positively associated with protamination (P = 0.002). The role of chance was limited and the findings have biological relevance and a pathophysiological explanation. LIMITATIONS, REASONS FOR CAUTION: For the present study, we deliberately selected only men with normozoospermia to better analyze whether STL might represent a biomarker of sperm quality beyond traditional sperm parameters. Additional studies in proven fertile men with normal sperm parameters are needed. WIDER IMPLICATIONS OF THE FINDINGS: The measurement of STL is a simple and rapid method that offers further information about the quality of sperm. The results of this study demonstrate that STL could be considered as an additional sperm parameter and opens new perspectives in the evaluation of the infertile male. Additional studies will clarify the significance of this parameter also as a prognostic biomarker in assisted reproduction. STUDY FUNDING/COMPETING INTERESTS: No external funding was either sought or obtained for this study. There are no conflicts of interest to be declared.

The Klinefelter syndrome is associated with high recurrence of copy number variations on the X chromosome with a potential role in the clinical phenotype.

The Klinefelter syndrome (KS) is the most frequent sex chromosomal disorder in males, characterized by at least one supernumerary X chromosome (most frequent karyotype 47,XXY). This syndrome presents with a broad range of phenotypes. The common characteristics include small testes and infertility, but KS subjects are at increased risk of hypogonadism, cognitive dysfunction, obesity, diabetes, metabolic syndrome, osteoporosis, and autoimmune disorders, which are present in variable proportion. Although part of the clinical variability might be linked to a different degree of testicular function observed in KS patients, genetic mechanisms of the supernumerary X chromosome might contribute. Gene-dosage effects and parental origin of the supernumerary X chromosome have been suggested to this regard. No study has been performed analyzing the genetic constitution of the X chromosome in terms of copy number variations (CNVs) and their possible involvement in phenotype of KS. To this aim, we performed a SNP arrays analysis on 94 KS and 85 controls. We found that KS subjects have more frequently than controls X-linked CNVs (39/94, [41.5%] with respect to 12/42, [28.6%] of females, and 8/43, [18.6%] of males, p < 0.01). The number of X-linked CNVs in KS patients was 4.58 ± 1.92 CNVs/subject, significantly higher with respect to that found in control females (1.50 ± 1.29 CNVs/subject) and males (1.14 ± 0.37 CNVs/subject). Importantly, 94.4% X-linked CNVs in KS subjects were duplications, higher with respect to control males (50.0%, p < 0.001) and females (83.3%, p = 0.1). Half of the X-linked CNVs fell within regions encompassing genes and most of them (90%) included genes escaping X-inactivation in the regions of X-Y homology, particularly in the pseudoautosomal region 1 (PAR1) and Xq21.31. This study described for the first time the genetic properties of the X chromosome in KS and suggests that X-linked CNVs (especially duplications) might contribute to the clinical phenotype.

D-Aspartic acid stimulates steroidogenesis through the delay of LH receptor internalization in a mammalian Leydig cell line.

PURPOSE: Recent experimental evidence on non-mammalian animal models showed that D-Aspartic acid (d-Asp) administration increases testosterone levels through upregulation of StAR in Leydig cells. In this study, we aimed to investigate in vitro the signaling pathway associated with d-Asp stimulation in MA-10 murine Leydig cells. METHODS: MA-10 cells were stimulated with different concentrations of d-Asp, in presence or absence of hCG. Then total testosterone (T) levels in the culture medium were evaluated by electrochemiluminescence immunoassay, and StAR and LHR protein expressions were quantified by the means of Western blotting. LHR cellular localization after hormonal stimulation was assessed by immunofluorescence. RESULTS: Stimulation with the sole d-Asp did not induce any relevant increase of T release from cultured cells. On the other hand, stimulation with hCG induced significant increase of T (P = 0.045). Concomitant stimulation with hCG and d-Asp, at the concentration of 0.1 and 1 nM, induced additional and significant increase of released T (P = 0.03 and P = 0.04, respectively). StAR protein levels increased after concomitant stimulation with hCG and d-Asp 0.1 nM, compared with stimulation with the sole hCG (P = 0.02), whereas no variation in LHR protein expression was observed. Finally, d-Asp attenuated displacement of LHR staining, from cell membrane to cytoplasm, subsequent to hCG stimulation. CONCLUSIONS: In this study, we confirmed a steroidogenic role for d-Asp, in concert with hCG, on murine Leydig cells, which is mediated by an increase in StAR protein levels. In addition, we showed that the possible mechanism subtending the effect of d-Asp could rely on the modulation of LHR exposure on the cell membrane.

Y chromosome haplogroups and susceptibility to testicular cancer.

Although in the past decades much progress in testicular cancer (TC) management has been made, little is known about the possible genetic causes and molecular mechanisms involved in its aetiopathogenesis. Some studies on possible contribution of the Y chromosome in TC development have been previously published, but data are not conclusive. In particular, ethnic influence and spermatogenic activity of patients with TC have not been adequately considered in previous studies, although they may represent important confounding factors. The objective of this study is to analyse the contribution of the Y chromosome in testicular germ cell cancer subjects who are well defined at the microgeographical, clinical and seminological level. We analysed Y chromosome classic azoospermia factor (AZF) deletions, partial AZFc deletions and Y haplogroups in 118 sporadic cases of testicular germ cell cancer and 93 microgeographically matched controls. Y chromosome screening failed to identify Y chromosome microdeletions in either cases or controls. Y chromosome haplogroup distribution and frequencies did not differ between cases and controls. Furthermore, no difference was observed when comparing patients with seminoma and non-seminoma, nor when comparing patients with TC with normozoospermia and azoo-oligozoospermia. Our findings combined with data reported so far suggest that classic AZF deletions and partial AZFc deletions are not a frequent cause or risk factor for TC and that different Y haplogroup distribution does not contribute to susceptibility to this tumour.