Potential detrimental effects of a phytoestrogen-rich diet on male fertility in mice.

Soy and soy-based products are widely consumed by infants and adult individuals. There has been speculation that the presence of isoflavone phytoestrogens in soybean cause adverse effects on the development and function of the male reproductive system. The purpose of this study was to examine the influence of dietary soy and phytoestrogens on testicular and reproductive functions. Male mice were fed from conception to adulthood with either a high soy-containing diet or a soy-free diet. Although adult mice fed a soy-rich diet exhibited normal male behaviour and were fertile, we observed a reduced proportion of haploid germ cells in testes correlating with a 25% decrease in epididymal sperm counts and a 21% reduction in litter size. LH and androgens levels were not affected but transcripts coding for androgen-response genes in Sertoli cells and Gapd-s, a germ cell-specific gene involved in sperm glycolysis and mobility were significantly reduced. In addition, we found that dietary soy decreased the size of the seminal vesicle but without affecting its proteolytic activity. Taken together, these studies show that long-term exposure to dietary soy and phytoestrogens may affect male reproductive function resulting in a small decrease in sperm count and fertility.

Topological origins of chromosomal territories.

Using freely jointed polymer model we compare equilibrium properties of crowded polymer chains whose segments are either permeable or not permeable for other segments to pass through. In particular, we addressed the question whether non-permeability of long chain molecules, in the absence of excluded volume effect, is sufficient to compartmentalize highly crowded polymer chains, similarly to what happens during formation of chromosomal territories in interphase nuclei. Our results indicate that even polymers without excluded volume compartmentalize and show strongly reduced intermingling when they are mutually non-permeable. Judging from the known fact that chromatin fibres originating from different chromosomes show very limited intermingling in interphase nuclei, we propose that regular chromatin fibres during chromosome decondensation can hardly serve as a substrate of cellular type II DNA topoisomerases.

Male mutation bias and possible long-term effects of human activities.

The ability of a population to adapt to changing environments depends critically on the amount and kind of genetic variability it possesses. Mutations are an important source of new genetic variability and may lead to new adaptations, especially if the population size is large. Mutation rates are extremely variable between and within species, and males usually have higher mutation rates as a result of elevated rates of male germ cell division. This male bias affects the overall mutation rate. We examined the factors that influence male mutation bias, and focused on the effects of classical life-history parameters, such as the average age at reproduction and elevated rates of sperm production in response to sexual selection and sperm competition. We argue that human-induced changes in age at reproduction or in sexual selection will affect male mutation biases and hence overall mutation rates. Depending on the effective population size, these changes are likely to influence the long-term persistence of a population.

Histological description of seminiferous epithelium and cycle length of spermatogenesis in the water shrew Neomys fodiens (Mammalia: Soricidae).

Recently, we examined the spermatogenesis cycle length in two shrews species, Sorex araneus characterized by a very high metabolic rate and a polyandric mating system (sperm competition) resulting in a short cycle and Crocidura russula characterized by a much lower metabolic rate and a monogamous mating system showing a longer cycle. In this study, we investigated the spermatogenesis cycle in Neomys fodiens showing an intermediate metabolic rate. We described the stages of seminiferous epithelium according to the spermatid morphology method and we calculated the cycle length of spermatogenesis using incorporation of 5-bromodeoxyuridine into DNA of the germ cells. Twelve males were injected intraperitoneally with 5-bromodeoxyuridine, and the testes were collected. For cycle length determination, we applied a recently developed statistical method. The calculated cycle length is 8.69 days and the total duration of spermatogenesis based on 4.5 cycles is approximately 39.1 days, intermediate between the duration of spermatogenesis of S. araneus (37.6 days) and C. russula (54.5 days) and therefore congruent with both the metabolic rate hypothesis and the sperm competition hypothesis. Relative testes size of 1.4% of body mass indicates a promiscuous mating system.

Relationships of basal metabolic rate, relative testis size and cycle length of spermatogenesis in shrews (Mammalia, Soricidae).

The aim of the present study was to determinate the cycle length of spermatogenesis in three species of shrew, Suncus murinus, Sorex coronatus and Sorex minutus, and to assess the relative influence of variation in basal metabolic rate (BMR) and mating system (level of sperm competition) on the observed rate of spermatogenesis, including data of shrew species studied before (Sorex araneus, Crocidura russula and Neomys fodiens). The dynamics of sperm production were determined by tracing 5-bromodeoxyuridine in the DNA of germ cells. As a continuous scaling of mating systems is not evident, the level of sperm competition was evaluated by the significantly correlated relative testis size (RTS). The cycle durations estimated by linear regression were 14.3 days (RTS 0.3%) in Suncus murinus, 9.0 days (RTS 0.5%) in Sorex coronatus and 8.5 days (RTS 2.8%) in Sorex minutus. In regression and multiple regression analyses including all six studied species of shrew, cycle length was significantly correlated with BMR (r2=0.73) and RTS (r2=0.77). Sperm competition as an ultimate factor obviously leads to a reduction in the time of spermatogenesis in order to increase sperm production. BMR may act in the same way, independently or as a proximate factor, revealed by the covariation, but other factors (related to testes size and thus to mating system) may also be involved.

Comment on reversal of hypogonadotropic hypogonadism in a Chinese cohort.

The reversal of congenital hypogonadotropic hypogonadism (CHH) is a relatively recent phenomenon that has gained increasing attention over the past 10 years. Yet to date, only one prospective study has been conducted estimating that 10% (95% confidence interval [CI]: 2%-18%) of cases undergo reversal. [1] Other retrospective studies have reported rates in the range of 5%-8% [2],[3] and a recent study showed 44/308 (14%, 95% CI: 11%-19%) CHH patients underwent reversal. [4] Moreover, a time-to-event analysis in this large cohort revealed a lifetime reversal incidence of 22%. The article by Mao and colleagues presented in this issue is a meaningful contribution to our understanding of reversal as it examines the largest retrospective cohort to date. [5] Interestingly, they report the rate of reversal as 5% (95% CI: 3%-8%) in this Chinese cohort. It is difficult to reconcile the discrepancies in rates of reversibility and direct comparisons are hampered by the variable definitions employed. Using a novel definition for reversal (i.e, either endogenous testosterone (T) >270 ng dl−1 , serum T gradually increasing above 150 ng dl−1 with increased testicular volume, or normal spontaneous sperm production/normal erectile function/ejaculation), Mao and colleagues posit that testicular size and triptorelin-stimulated LH levels are reliable predictive factors for reversal. However, these cannot be considered as hard and fast rules for predicting reversal as the groups intersect - akin to the overlap observed between CHH patients and those with delayed puberty. Indeed, the fact that approximately half (44%, 95% CI: 25%-66%) of the reversal patients in the study by Mao et al.[5] were diagnosed between 17 and 19 years of age, underscores the challenge in differentiating CHH from extreme normal variants of puberty. This study further lends credence the recently reported observations that reversals may relapse. [4],[6] The notion that reversal may not be lasting highlights the vulnerability of the reproductive axis among CHH patients. While the mechanism(s) for relapse are unclear, it seems plausible that environmental, metabolic or psychiatric stressors could contribute. The factors that Mao and colleagues identify as significantly different in cases of reversal, were not informative for identifying those cases that relapsed back to a hypogonadal state. Notably, reversal has been reported in probands harboring mutations in genes underlying CHH. [1],[3],[4],[6] Unfortunately, comprehensive genetic screening on the Chinese cohort is not available. The reversal phenomenon is fascinating for its glimpse into the plasticity of the neuroendocrine control of reproduction. Future directions will almost certainly include investigation of specific genetic signatures and novel biomarkers for predicting reversal (and relapse). Yet CHH is a rare condition and to fully elucidate the biology of reversible CHH, it will be important to harmonize definitions of what constitutes a reversal, carefully phenotype patients and chart the natural history of their CHH. In this way, this unique human disease model may offer further insights into the control of human reproduction and provide opportunities to translate discoveries into enhanced approaches to improve the care and quality of life for these patients.

Anxiety, depression, and attachment before and after the first-trimester screening for Down syndrome: comparing couples who undergo ART with those who conceive spontaneously.

OBJECTIVES: This study's aim was to describe the emotional status of parents to be before and after the first-trimester combined prenatal screening test. METHODS: One hundred three couples participated, of which 52 had undergone an in vitro fertilization/intracytoplasmic sperm injection treatment [assisted reproductive technology (ART)] and 51 had conceived spontaneously. Participants completed the state scale of the State-trait Anxiety Inventory, the Edinburgh Depression Scale, and the Maternal and Paternal Antenatal Attachment Questionnaire before the first-trimester combined prenatal screening test at around 12 weeks of gestational age (T1) and just after receiving the results at approximately 14 weeks of gestational age (T2). RESULTS: We observed a significant decrease in anxiety and depression symptoms and a significant increase in attachment from T1 to T2. Results showed no differences between groups at either time point, which suggests that ART parents are more similar to than different from parents conceiving spontaneously. Furthermore, given the importance of anxiety during pregnancy, a subsample of women with clinical anxiety was identified. They had significantly higher rates of clinical depression and lower attachment. CONCLUSIONS: These results indicate that, regardless of whether conception was through ART or spontaneous, clinical anxiety in women over the prenatal testing period is associated with more vulnerability during pregnancy (i.e. clinical depression and less attachment to fetus). © 2015 John Wiley & Sons, Ltd.

A new approach for the separation of spermatozoa from other cell types in forensically relevant samples.

Due to imbalance in genetic material contribution, gynecological samples collected following a sexual assault are challenging to process in order to resolve the male contributor's DNA profile. We set up a new and fast procedure for the recovery and separation of cells from cotton swabs, or other supports. Using spermatozoa specific CD52 antibody coupled to magnetic beads along with magnetic columns, this procedure was first developed and optimized by flow cytometry. It allows the recovery of two enriched cell fractions: a sperm fraction, mostly enriched with the alleged offender's spermatozoa, and a non-sperm fraction, mostly enriched with cells from the victim. Processing fresh as well as six months old mock samples, made of buccal swabs loaded with sperm dilutions, resulted in full single NGM SElect DNA profiles of the sperm donors, respectively the epithelial cells donors, for the sperm and the non-sperm fractions. Untreated duplicate samples processed in parallel only provided the autosomal DNA profiles of the epithelial cells donors. This new procedure can be rapidly tested and adopted by forensic laboratories worldwide as it uses material already commercially available. Moreover it can be easily automated with existing platform, and could therefore provide a mean to rapidly reduce existing backlogs.

Ejaculate Characteristics Depend on Social Environment in the Horse (Equus caballus).

Sperm competition theory predicts semen characteristics to be affected by the social environment. We used the polygamous horse (Equus caballus) to experimentally study within-subject plasticity in response to different social environments. Stallions were sequentially exposed, over a period of 8 weeks each, to other stallions and then singly to mares, or vice versa (in adjacent boxes separated by grills). Ejaculates were collected to determine semen characteristics. Highest sperm numbers were found in stallions that were first exposed to other stallions and then to mares, while lowest sperm numbers were observed in stallions that had been exposed to mares but not yet to other stallions. One of three sperm velocity measures (curvilinear velocity) was consistently elevated in stallions that were first exposed to stallions and then to mares. Sperm number after exposure to mares and curvilinear sperm velocity after exposure to stallions were both positively correlated to average blood testosterone levels during the corresponding period of exposure. We conclude that ejaculate characteristics are plastic traits affected by the social environment in horses.