Journal of andrology最新文献

ABSTRACT: We have shown previously that the in vitro exposure of spermatozoa to elementary bodies (EBs) of Chlamydia trachomatis can lead to sperm death over a number of hours of incubation. As such, we have hypothesized that the ejaculates of men with a chlamydial infection could contain increased numbers of nonmotile (dead) spermatozoa if they are exposed to EBs prior to ejaculation. To test this hypothesis, the ejaculates of 642 men undergoing diagnostic semen analysis as part of ongoing infertility investigations with their partner were examined. All men were without symptoms of genitourinary infections and semen analysis was performed according to World Health Organisation (WHO) 1999 methods after a 3–5 day abstinence period. In addition to semen analysis, nested plasmid polymerase chain reaction (PCR) was undertaken on the ejaculate to detect the presence of C trachomatis DNA. A total of 31 semen specimens (4.9%) were found to be positive, and in 28 of these, the diagnosis was confirmed using the ligase chain reaction (LCR). Men whose ejaculates were PCR positive for chlamydial DNA had a significantly (P < .05) higher mean concentration of leukocytes (1.71 ± 2.20 × 10⁶ per mL) and a higher mean ejaculate volume (3.45 ± 1.52 mL) than in those whose ejaculates were PCR negative (leukocyte concentration: 0.67 ± 2.59 × 10⁶ per mL; volume 2.93 ± 1.38 mL). Leukocytospermia was twice as common in men that were PCR positive for chlamydial DNA (P < .05) but it was not always associated with the presence of chlamydial DNA in semen. However, there was no difference in the mean percent motility between the 2 groups and the proportion of asthenozoospermia also did not differ. Because these results do not confirm the hypothesis proposed from our in vitro experiments, further work needs to be undertaken to understand whether human spermatozoa are actually exposed to elementary bodies of C trachomatis in an infected individual prior to ejaculation.

ABSTRACT: Androgens drive male secondary sexual differentiation and maturation. Mutations in the androgen receptor (AR) gene cause a broad spectrum of abnormal phenotypes in humans, ranging from mild through partial to complete androgen insensitivity. We have analyzed the AR gene by using denaturing high-performance liquid chromatography (DHPLC) and direct sequencing and have studied gonads histologically in a familial case of complete androgen insensitivity syndrome. Sequence analysis of the AR gene showed a novel C2578T missense mutation, resulting in the replacement of a highly conserved leucine residue with phenylalanine (L859F) in ligand-binding domain of the receptor. The residue L859, located in helix 10 of the androgen receptor, plays a significant role in overall architecture of ligand-binding pocket. The mutation was absent from the father, normal brother of the patients, and 100 normal males recruited in this study as controls. The inheritance of the mutation in the family clearly shows that C2578T is the underlying mutation for the eventual phenotype in the patients. Histology of patient's gonads showed Leydig cell hyperplasia, with a few or no spermatogonium. It is thought that AR gene mutations result in hormonal imbalance, resulting in the high levels of luteinizing hormone (LH) and ultimately Leydig cell hyperplasia or tumor formation. In the present study, we have reported a rare familial case of Leydig cell hyperplasia despite consistently normal LH levels. The finding will help in giving counseling to this family and prevent the transmission of the mutated X chromosome to the coming generations.

ABSTRACT: SAMMA is licensed for development as a contraceptive microbicide. Understanding mechanisms of its biological activity is prerequisite to designing more active second generation products. This study examined Ca²⁺ involvement in SAMMA-induced premature acrosomal loss (SAL) in noncapacitated human spermatozoa. SAMMA causes acrosomal loss (AL) in a dose-dependent manner (ED₅₀ = 0.25 μg/mL). SAL requires extracellular Ca²⁺ (ED₅₀ = 85 μM). SAL is inhibited by verapamil (nonspecific voltage-dependent Ca²⁺ channel blocker; IC₅₀ = 0.4 μM), diphenylhydantoin and NiCl₂ (T-type [Ca_v3.x] channel blockers; IC₅₀ 210 μM and 75 μM, respectively). Verapamil blockade of L-type (Ca_v1.x) channels is use-dependent; activated channels are more sensitive to inhibition. However, verapamil inhibition of SAL does not increase after repeated SAMMA stimulation. SAL is unaffected by 10 μM nifedipine (selective L-type channel blocker). This contrasts to 40% inhibition (P < .001) of AL induced by 1 μM thapsigargin (Ca²⁺-ATPase inhibitor; releases intracellular Ca²⁺ stores, promotes capacitative Ca²⁺ entry). SAL is unaffected by 1 μM BAPTA-AM (intracellular Ca²⁺ chelator), and 50 μM 2-APB (blocks InsP3 receptors and store-operated channels). This contrasts with thapsigargin-induced AL, inhibited nearly 65% by BAPTA-AM (P < .005) and 91% by 2-APB (P, .001). The results suggest that SAL is mediated by Ca²⁺ entry through channels pharmacologically similar to the T-type (Ca_v3.2) class. This process appears distinct from that caused by physiological stimuli such as progesterone or zona pellucida-derived proteins. SAMMA's contraceptive activity may be caused by induction of premature AL through dysregulation of Ca²⁺ signaling.

ABSTRACT: Semenogelins I and II are major coagulum-forming proteins in semen, and they are secreted mainly by the seminal vesicles. These proteins bind Zn²⁺ and act as substrates for prostate-specific antigen and transglutaminase. A variant semenogelin I lacking 60 amino acids has been described that occurs in different populations with an allele frequency of 1%–3%. To better understand the function of the semenogelins in vivo, our aim was to characterize the properties of the variant form and compare with the wild type. Recombinant proteins were synthesized in insect cells. Binding of Zn²⁺ was studied by titration of metal ions in the presence of a zinc (II) fluorophore chelator. SDS-PAGE was used to visualize the results of cleavage by prostate-specific antigen and cross-linking with transglutaminase. We found that the truncated and wild-type semenogelin molecules had similar Zn²⁺-binding properties (ie, a stoichiometry of at least 9–10 mol per mol of protein and an average dissociation constant of 5 μmol/L per site), and they showed also similar susceptibility for degradation by prostate-specific antigen. Furthermore, like the wild-type form, the truncated semenogelin I was able to serve as a substrate for transglutaminase. These findings imply that the studied characteristics do not depend on a well-defined tertiary structure, or that the deletion has no major effect on the structure responsible for these features.

ABSTRACT: Physiological aging is a significant risk factor in the on-set of male erectile dysfunction (ED) and an imbalance in factors that modulate cavernosal smooth-muscle tone may play a role in these altered penile hemodynamic mechanisms. To evaluate the association between aging and male erectile function, we monitored neurogenic erectile response and its correlation to systemic arterial pressure changes in old (21–23 months of age) vs young (6–9 months of age) Brown-Norway (BN) rats. We tested the hypothesis that age-associated ED is due to unregulated vasoconstrictive tone, contributed in part by an increased Rho-kinase activity, and that antagonism of Rho-kinase activity attenuates the age-related decline in male erectile function. We also examined the hypothesis that a combination of Rho-kinase antagonism and phosphodiesterase-5 (PDE-5) inhibition has a synergistic effect in improving the erectile response in these aging animals. Erectile function in old BN rats was evaluated before and after intracavernosal injection of a specific inhibitor of Rho-kinase (Y-27632) alone or in combination with zaprinast, a PDE-5 inhibitor. Erectile capabilities of the young and old BN rat groups were significantly different in corpus cavernosum pressure response after electrical-field stimulation of the major pelvic ganglion. Y-27632 administration attenuated the aging-related changes in male erectile function seen in BN rats. Rho-kinase antagonism and PDE-5 inhibition had a synergistic effect in improving erectile function in old rats. Our data indicate that aging leads to impairment in the neurogenic erectile response in BN rats involving a possible derangement in penile hemodynamic mechanisms of the erectile tissue. Rho-kinase inhibition may be of value in treating age-related ED.

ABSTRACT: On days 7–21 of gestation, Sprague-Dawley rats were orally administered 3 or 30 μg/kg/d of 3,3′,4,4′,5-pentachlorobiphenyl (PCB126) or 3,3′,4,4′,5,5′-hexachlorobiphenyl (PCB169) daily. Their male offspring were autopsied at 3, 6, and 15 weeks after birth to investigate the effects of the 2 polychlorinated biphenyls (PCBs) on spermatogenesis and steroidogenesis in their testes. PCB treatment caused a decrease in the area ratio of 3β-hydroxysteroid dehydrogenase (HSD)-expressing cells (Leydig cells)/testis at 3 weeks after birth. When PCB126 was administered to pregnant rats, the plasma testosterone levels in their offspring were decreased at 3 weeks. The expression levels of P450scc, 3β-HSD, and P450_17α mitochondrial RNAs (mRNAs) were unchanged, although the StAR (steroidogenic acute regulatory protein) mRNA expression level was increased at 6 weeks. On the other hand, when PCB169 was administered, plasma testosterone levels were decreased at 3 and 6 weeks and were increased at 15 weeks. Plasma luteinizing hormone (LH) levels were decreased at 6 weeks, and plasma follicle-stimulating hormone (FSH) levels were increased at 15 weeks. The expression levels of 3β-HSD and P450_17α were increased, and the mRNA level of 5α-reductase 1 was decreased at 15 weeks. PCB169 treatment suppressed the conversion of round spermatids between stages VII and VIII. These results indicate that in utero and lactational exposure to PCB126 or PCB169 decreases plasma testosterone levels in 3-week-old rats, with no change in the expression levels of the mRNAs of enzymes, and that PCB169 inhibits testicular steroid synthesis more strongly than PCB126. PCB169 greatly altered the concentration of testosterone, indicating a stronger inhibitory effect on spermatogenesis. Low testosterone and LH levels in prenatally PCB169-exposed rats until 6 weeks after birth presumably retard the functional differentiation of testicular Leydig cells; however, the increased testosterone levels at 15 weeks suggest that Leydig cells in PCB-exposed rats are virtually mature by the 15th week.

The past 30 years have been marked by unparalleled accomplishments in the medical treatment of malignancy. Prior to advances in chemotherapeutic and radiation treatment, many oncologic conditions had dismal survival rates. Today, medical interventions have success rates that approach complete remission for many malignancies. An inadvertent complication of these therapies, however, has been the high rate of infertility following treatment. Male germinal tissue, like many malignancies, is mitotically active and therefore is particularly susceptible to the toxic effects of both chemotherapy and radiotherapy (Meistrich et al, 1982; Meistrich, 1993). Consequently, posttreatment patients often develop severe oligozoospermia or azoospermia (Wallace et al, 1991). Potential infertility complications can be anticipated, and adult male patients interested in future procreation are counseled to cryopreserve semen before instituting treatment. With present-day capabilities of in vitro fertilization, particularly intracytoplasmic injection, male patients can maintain posttreatment fertility. Pretreatment sperm banking, however, is not a viable option for prepubescent males. These individuals have not yet begun spermatogenesis and thus lack viable spermatozoa. It is estimated that, by the end of the decade, 1 in 250 young men will be childhood cancer survivors (Blatt, 1999). For these patients, infertility has often been an accepted consequence of their life-saving treatment.

A great deal of interest has recently been shown in testicular autologous transplantation, an intervention that may provide a future therapeutic fertility option for these individuals. Having been successfully demonstrated in rodent models, investigators have now begun to explore the possibility of using testicular autotransplantation to restore fertility in humans. This paper will review the history of spermatogonia transplantation with an emphasis on the clinical pertinence of this field of investigation. Current innovations involving the isolation of spermatogonial stem cells (SSCs) and the present capabilities of in vitro proliferation will additionally be reviewed.

Spermatogonia are male germinal progenitor cells and are composed of differentiated nonstem and stem cells. Stem cells are characterized by a capacity for self-renewal and an ability to produce differentiating cell lines (Loeffler and CS, 1997; van der Kooy and Weiss, 2000). Spermatogonia are diploid germ cells that originated from primordial germ cells (PGCs). These precursor cells originate from embryonal ectoderm. PGCs migrate to the genital ridge, where they become known as gonocytes. Gonocytes are surrounded by Sertoli precursor cells in what become the seminiferous cords. Tight junctions between adjacent Sertoli cells later become the basis of the blood testis barrier. The gonocytes undergo mitotic division, followed by arrest in the G0 phase of the cell cycle. They are mitotically inactive until after

ABSTRACT: A body of evidence indicates that morphologically abnormal human spermatozoa may exhibit impaired ability to fertilize. Yet teratospermia has widely varying etiologies, including associations with varicoceles, following fever, cigarette smoking, and exposure to polychlorinated biphenyls. Abnormalities of sperm shape in mice have also been shown to be associated with autosomal gene mutations. These varying causes of teratospermia could have different molecular consequences reflected in altered sperm function. We studied the ability of morphologically abnormal human sperm to penetrate zona-free hamster eggs as a measure of their ability to undergo an acrosome reaction and gamete membrane fusion. Motile sperm from ejaculates containing 15% normal sperm or less, as judged by World Health Organization (1999) criteria, were recovered by ISolate density centrifugation and capacitated by overnight incubation. Zona-free hamster eggs were inseminated with 1 × 10⁶ motile capacitated cells and scored for sperm penetration after 3 hours of coincubation. A significant trend was found between the percent of abnormal spermatozoa within the ejaculate and impaired egg-penetrating ability, reflected in the percent of eggs penetrated, the number of penetrating sperm per egg, and the number of sperm adherent to the oolemma. Because only acrosome-reacted human spermatozoa adhere to the oolemma, these results support the notion that abnormally shaped sperm may exhibit an impaired ability to undergo an acrosome reaction. A correlation was also noted between the loss of motility of sperm following overnight incubation and impairment of their ability to undergo gamete membrane fusion. These results confirm prior findings at the level of the zona pellucida that abnormally shaped sperm exhibit functional abnormalities. However, a wide variation was observed between men in the behavior of such sperm, including occasionally high rates of egg penetration. These observations suggest that assessment of morphology may be an unreliable measure, for the individual, of sperm fertilizing ability and emphasize that sperm function testing is an important part of the evaluation of teratospermia.

ABSTRACT: Past studies have shown that the epithelial lining of the epididymis in adult mice deficient in protective protein cathepsin A (PPCA −/−) becomes swollen and vacuolated as a result of an accumulation of pale lysosomes, some very large, in addition to the presence of an abundance of macrophages infiltrating the intertubular spaces. The purpose of this study was to assess the integrity of the epididymal epithelial—blood barrier in these altered mice by characterizing the distribution of claudins (Cldns) and the leakiness of tight junctions to lanthanum nitrate. A second goal was to characterize sperm motility behavior in PPCA −/− mice using computer-assisted sperm analyses (CASA). The results indicated that lanthanum nitrate penetrated apical junctional complexes between adjacent epithelial cells and entered the epididymal lumen in PPCA −/− mice but not in control PPCA +/+ mice. Immunostaining for Cldns 1, 3, 8, and 10 revealed unique patterns of expression based on cell type and region specificity in PPCA +/+ mice, which were much different in PPCA –/– mice. PPCA –/– mice showed reduced intensities of immunoreactions, complete absence of immunoreactions, and appearance of atypical cytoplasmic immunoreactions. CASA indicated that sperm counts in the PPCA –/– mice were 70% reduced, and among other problems, there was a fourfold higher percentage of static sperm in PPCA –/– mice compared with controls. These results suggest that PPCA deficiency causes structural changes to the blood-epididymal barrier as evidenced by lanthanum nitrate and Cldns expression that affects the luminal environment of the epididymis, resulting in altered sperm motility.

ABSTRACT: This study aimed to examine the association between the interval from ejaculation to analysis and epididymal and accessory sex gland function in relation to sperm motility. Ejaculates from 1079 men assessed for infertility were analyzed according to World Health Organization guidelines. Biochemical markers were measured in semen to assess the function of the epididymis (neutral α-glucosidase [NAG]), prostate (prostate-specific antigen [PSA] and zinc), and seminal vesicles (fructose). Three groups were defined according to time from ejaculation to analysis: G_≤30 (24–30 minutes), G_31–60 (31–60 minutes), and G_>60 (63–180 minutes). The proportion of progressively motile sperm was significantly lower in G_>60 than in G_≤30 (mean difference, 8.0%; 95% confidence interval [CI], 2.0%–13%) or G_31–60 (mean difference, 6.0%; 95% CI, 1.0%–12%). The proportion of rapid progressive sperm motility was significantly higher in G_≤30 compared with G_31–60 (mean difference, 3.0%; 95% CI, 1.0%–5.0%) and G_>60 (mean difference, 6.0%; 95% CI, 1.0%–10%). Sperm morphology and viability did not vary significantly between the groups. However, PSA levels in G_>60 were 29% and 31% significantly lower than in G_≤30 (95% CI, 3.0%–54%) and G_31–60 (95% CI, 7.0%–58%), respectively. Moreover, men in G_>60 had 29% and 17% significantly lower zinc compared with those in G_≤30 (95% CI, 4.0%–69%) and G_31–60 (95% CI, 4.0%–64%), respectively. Levels of NAG and fructose did not differ significantly between the groups. There were negative associations between the ejaculation-to-analysis interval and sperm motility and levels of PSA and zinc. In male infertility assessments, semen analysis should be performed within 60 minutes of ejaculation.