Normal sex differences in prenatal growth and abnormal prenatal growth retardation associated with 46,XY disorders of sex development are absent in newborns with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Background

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is the most common presentation of a disorder of sex development (DSD) in genetic females. A report of prenatal growth retardation in cases of 46,XY DSD, coupled with observations of below-optimal final height in both males and females with congenital adrenal hyperplasia due to 21-hydroxylase deficiency, prompted us to investigate prenatal growth in the latter group. Additionally, because girls with congenital adrenal hyperplasia are exposed to increased levels of androgens in the absence of a male sex-chromosome complement, the presence or absence of typical sex differences in growth of newborns would support or refute a hormonal explanation for these differences.

Methods

In total, 105 newborns with congenital adrenal hyperplasia were identified in our database. Gestational age (weeks), birth weight (kg), birth length (cm) and parental heights (cm) were obtained. Mid-parental height was considered in the analyses.

Results

Mean birth weight percentile for congenital adrenal hyperplasia was 49.26%, indicating no evidence of a difference in birth weight from the expected standard population median of 50th percentile (P > 0.05). The expected sex difference in favor of heavier males was not seen (P > 0.05). Of the 105 subjects, 44 (27%; 34 females, 10 males) had birth length and gestational age recorded in their medical chart. Mean birth length for this subgroup was 50.90 cm (63rd percentile), which differed from the expected standard population median of 50th percentile (P = 0.0082). The expected sex difference in favor of longer males was also not seen (P > 0.05).

Conclusion

The prenatal growth retardation patterns reported in cases of 46,XY disorders of sex development do not generalize to people with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. Sex differences in body weight and length typically seen in young infants were not seen in the subjects who participated in this study. We speculate that these differences were ameliorated in this study because of increased levels of prenatal androgens experienced by the females infants.     

Genetic analysis of male reproductive success in relation to density in the zebrafish, Danio rerio

Background

We used behavioural and genetic data to investigate the effects of density on male reproductive success in the zebrafish, Danio rerio. Based on previous measurements of aggression and courtship behaviour by territorial males, we predicted that they would sire more offspring than non-territorial males.

Results

Microsatellite analysis of paternity showed that at low densities territorial males had higher reproductive success than non-territorial males. However, at high density territorial males were no more successful than non-territorials and the sex difference in the opportunity for sexual selection, based on the parameter I _mates, was low.

Conclusion

Male zebrafish exhibit two distinct mating tactics; territoriality and active pursuit of females. Male reproductive success is density dependent and the opportunity for sexual selection appears to be weak in this species.     

The impact of sex on brain responses to smoking cues: a perfusion fMRI study

Background

Anecdotal and clinical theories purport that females are more responsive to smoking cues, yet few objective, neurophysiological examinations of these theories have been conducted. The current study examines the impact of sex on brain responses to smoking cues.

Methods

Fifty-one (31 males) cigarette-dependent sated smokers underwent pseudo- continuous arterial spin-labeled perfusion functional magnetic resonance imaging during exposure to visual smoking cues and non-smoking cues. Brain responses to smoking cues relative to non-smoking cues were examined within males and females separately and then compared between males and females. Cigarettes smoked per day was included in analyses as a covariate.

Results

Both males and females showed increased responses to smoking cues compared to non-smoking cues with males exhibiting increased medial orbitofrontal cortex and ventral striatum/ventral pallidum responses, and females showing increased medial orbitofrontal cortex responses. Direct comparisons between male and female brain responses revealed that males showed greater bilateral hippocampal/amygdala activation to smoking cues relative to non-smoking cues.

Conclusions

Males and females exhibit similar responses to smoking cues relative to non-smoking cues in a priori reward-related regions; however, direct comparisons between sexes indicate that smoking cues evoke greater bilateral hippocampal/amygdalar activation among males. Given the current literature on sex differences in smoking cue neural activity is sparse and incomplete, these results contribute to our knowledge of the neurobiological underpinnings of drug cue reactivity.

     

Sex chromosome complement contributes to sex differences in coxsackievirus B3 but not influenza A virus pathogenesis

Background

Both coxsackievirus B3 (CVB3) and influenza A virus (IAV; H1N1) produce sexually dimorphic infections in C57BL/6 mice. Gonadal steroids can modulate sex differences in response to both viruses. Here, the effect of sex chromosomal complement in response to viral infection was evaluated using four core genotypes (FCG) mice, where the Sry gene is deleted from the Y chromosome, and in some mice is inserted into an autosomal chromosome. This results in four genotypes: XX or XY gonadal females (XXF and XYF), and XX or XY gonadal males (XXM and XYM). The FCG model permits evaluation of the impact of the sex chromosome complement independent of the gonadal phenotype.

Methods

Wild-type (WT) male and female C57BL/6 mice were assigned to remain intact or be gonadectomized (Gdx) and all FCG mice on a C57BL/6 background were Gdx. Mice were infected with either CVB3 or mouse-adapted IAV, A/Puerto Rico/8/1934 (PR8), and monitored for changes in immunity, virus titers, morbidity, or mortality.

Results

In CVB3 infection, mortality was increased in WT males compared to females and males developed more severe cardiac inflammation. Gonadectomy suppressed male, but increased female, susceptibility to CVB3. Infection with IAV resulted in greater morbidity and mortality in WT females compared with males and this sex difference was significantly reduced by gonadectomy of male and female mice. In Gdx FCG mice infected with CVB3, XY mice were less susceptible than XX mice. Protection correlated with increased CD4+ forkhead box P3 (FoxP3)+ T regulatory (Treg) cell activation in these animals. Neither CD4+ interferon (IFN)γ (T helper 1 (Th1)) nor CD4+ interleukin (IL)-4+ (Th2) responses differed among the FCG mice during CVB3 infection. Infection of Gdx FCG mice revealed no effect of sex chromosome complement on morbidity or mortality following IAV infection.

Conclusions

These studies indicate that sex chromosome complement can influence pathogenicity of some, but not all, viruses.     

Analysis of retinal cell development in chick embryo by immunohistochemistry and in ovo electroporation techniques

Background

Endogenous peptides such as neuropeptides are involved in numerous biological processes in the fully developed brain but very little is known about their role in brain development. Japanese quail is a commonly used bird model for studying sexual dimorphic brain development, especially adult male copulatory behavior in relation to manipulations of the embryonic endocrine system. This study uses a label-free liquid chromatography mass spectrometry approach to analyze the influence of age (embryonic days 12 vs 17), sex and embryonic day 3 ethinylestradiol exposure on the expression of multiple endogenous peptides in the developing diencephalon.

Results

We identified a total of 65 peptides whereof 38 were sufficiently present in all groups for statistical analysis. Age was the most defining variable in the data and sex had the least impact. Most identified peptides were more highly expressed in embryonic day 17. The top candidates for EE₂ exposure and sex effects were neuropeptide K (downregulated by EE₂ in males and females), gastrin-releasing peptide (more highly expressed in control and EE₂ exposed males) and gonadotropin-inhibiting hormone related protein 2 (more highly expressed in control males and displaying interaction effects between age and sex). We also report a new potential secretogranin-2 derived neuropeptide and previously unknown phosphorylations in the C-terminal flanking protachykinin 1 neuropeptide.

Conclusions

This study is the first larger study on endogenous peptides in the developing brain and implies a previously unknown role for a number of neuropeptides in middle to late avian embryogenesis. It demonstrates the power of label-free liquid chromatography mass spectrometry to analyze the expression of multiple endogenous peptides and the potential to detect new putative peptide candidates in a developmental model.     

Algorithms to predict cerebral malaria in murine models using the SHIRPA protocol

Background

Metabolic changes in the host in response to Plasmodium infection play a crucial role in the pathogenesis of malaria. Alterations in metabolism of male and female mice infected with Plasmodium berghei ANKA are reported here.

Methods

¹H NMR spectra of urine, sera and brain extracts of these mice were analysed over disease progression using Principle Component Analysis and Orthogonal Partial Least Square Discriminant Analysis.

Results

Analyses of overall changes in urinary profiles during disease progression demonstrate that females show a significant early post-infection shift in metabolism as compared to males. In contrast, serum profiles of female mice remain unaltered in the early infection stages; whereas that of the male mice changed. Brain metabolite profiles do not show global changes in the early stages of infection in either sex. By the late stages urine, serum and brain profiles of both sexes are severely affected. Analyses of individual metabolites show significant increase in lactate, alanine and lysine, kynurenic acid and quinolinic acid in sera of both males and females at this stage. Early changes in female urine are marked by an increase of ureidopropionate, lowering of carnitine and transient enhancement of asparagine and dimethylglycine. Several metabolites when analysed individually in sera and brain reveal significant changes in their levels in the early phase of infection mainly in female mice. Asparagine and dimethylglycine levels decrease and quinolinic acid increases early in sera of infected females. In brain extracts of females, an early rise in levels is also observed for lactate, alanine and glycerol, kynurenic acid, ureidopropionate and 2-hydroxy-2-methylbutyrate.

Conclusions

These results suggest that P. berghei infection leads to impairment of glycolysis, lipid metabolism, metabolism of tryptophan and degradation of uracil. Characterization of early changes along these pathways may be crucial for prognosis and better disease management. Additionally, the distinct sexual dimorphism exhibited in these responses has a bearing on the understanding of the pathophysiology of malaria.     

Stress amplifies sex differences in primate prefrontal profiles of gene expression

Background

Stress is a recognized risk factor for mood and anxiety disorders that occur more often in women than men. Prefrontal brain regions mediate stress coping, cognitive control, and emotion. Here, we investigate sex differences and stress effects on prefrontal cortical profiles of gene expression in squirrel monkey adults.

Methods

Dorsolateral, ventrolateral, and ventromedial prefrontal cortical regions from 18 females and 12 males were collected after stress or no-stress treatment conditions. Gene expression profiles were acquired using HumanHT-12v4.0 Expression BeadChip arrays adapted for squirrel monkeys.

Results

Extensive variation between prefrontal cortical regions was discerned in the expression of numerous autosomal and sex chromosome genes. Robust sex differences were also identified across prefrontal cortical regions in the expression of mostly autosomal genes. Genes with increased expression in females compared to males were overrepresented in mitogen-activated protein kinase and neurotrophin signaling pathways. Many fewer genes with increased expression in males compared to females were discerned, and no molecular pathways were identified. Effect sizes for sex differences were greater in stress compared to no-stress conditions for ventromedial and ventrolateral prefrontal cortical regions but not dorsolateral prefrontal cortex.

Conclusions

Stress amplifies sex differences in gene expression profiles for prefrontal cortical regions involved in stress coping and emotion regulation. Results suggest molecular targets for new treatments of stress disorders in human mental health.

     

Animal welfare in modern dog breeding

Background

While gross morphological changes in the skeleton between males and females are well know, differences between sexes in the histomorphology are less known. It is important to have knowledge on the bone structure of rabbits, as this is a widely used species in biomedical research. A study was performed to evaluate the association between sex and the compact bone morphology of the femoral diaphysis in juvenile rabbits.

Methods

Seventeen clinically healthy 2–3 month-old rabbits (9 females, 8 males) were included in the study. The rabbits were euthanized and the right femur was sampled for analysis. 70–80 microns thick bone sections of the femoral diaphysis were prepared using standard histological equipment. The qualitative histological characteristics were determined according to internationally accepted classification systems while the quantitative parameters were assessed using the software Scion Image. Areas, perimeters, minimum and maximum diameters of primary osteons' vascular canals, Haversian canals and secondary osteons were measured. Additionally, blood plasma concentrations of progesterone, corticosterone, IGF-I, testosterone and estradiol were analyzed.

Results

Qualitative histological characteristics were similar for both sexes. However, variations of certain quantitative histological characteristics were identified. Measured parameters of the primary osteons' vascular canals were higher in males than for females. On the other hand, females had significant higher values of secondary osteons parameters. Differences in Haversian canals parameters were only significant for minimum diameter.

Conclusion

The study demonstrated that quantitative histological characteristics of compact bone tissue of the femoral diaphysis in juvenile rabbits were sex dependent. The variations may be associated with different growth and modeling of the femur through influence by sex-specific steroids, mechanical loads, genetic factors and a multitude of other sources. The results can be applied in experimental studies focusing on comparison of the skeletal biology of the sexes.     

Behavioral and physiological female responses to male sex ratio bias in a pond-breeding amphibian

Introduction

The phenomenon of sexual conflict has been well documented, and in populations with biased operational sex ratios the consequences for the rarer sex can be severe. Females are typically a limited resource and males often evolve aggressive mating behaviors, which can improve individual fitness for the male while negatively impacting female condition and fitness. In response, females can adjust their behavior to minimize exposure to aggressive mating tactics or minimize the costs of mating harassment. While male-male competition is common in amphibian mating systems, little is known about the consequences or responses of females. The red-spotted newt (Notophthalmus viridescens) is a common pond-breeding amphibian with a complex, well-studied mating system where males aggressively court females. Breeding populations across much of its range have male-biased sex ratios and we predicted that female newts would have behavioral mechanisms to mitigate mating pressure from males. We conducted four experiments examining the costs and behavioral responses of female N. viridescens exposed to a male-biased environment.

Results

In field enclosures, we found that female newts exposed to a male-biased environment during the five-month breeding season ended with lower body condition compared to those in a female-biased environment. Shorter-term exposure to a male-biased environment for five weeks caused a decrease in circulating total leukocyte and lymphocyte abundance in blood, which suggests females experienced physiological stress. In behavioral experiments, we found that females were more agitated in the presence of male chemical cues and females in a male-biased environment spent more time in refuge than those in a female-biased environment.

Conclusions

Our results indicate that male-biased conditions can incur costs to females of decreased condition and potentially increased risk of infection. However, we found that females can also alter their behavior and microhabitat use under a male-biased sex ratio. Consistent with surveys showing reduced detection probabilities for females, our research suggests that females avoid male encounters using edge and substrate habitat. Our work illustrates the integrated suite of impacts that sexual conflict can have on the structure and ecology of a population.     

The association of the ankle-brachial index with incident coronary heart disease: the Atherosclerosis Risk In Communities (ARIC) study, 1987–2001

Background

We have developed a rat cell model for studying collagen type I production in coronary artery adventitial fibroblasts. Increased deposition of adventitial collagen type I leads to stiffening of the blood vessel, increased blood pressure, arteriosclerosis and coronary heart disease. Although the source and mechanism of collagen deposition is yet unknown, the adventitia appears to play a significant role. To demonstrate the application of our cell model, cultured adventitial fibroblasts were treated with sex hormones and the effect on collagen production measured.

Methods

Hearts (10–12 weeks) were harvested and the left anterior descending coronary artery (LAD) was isolated and removed. Tissue explants were cultured and cells (passages 2–4) were confirmed as fibroblasts using immunohistochemistry. Optimal conditions were determined for cell tissue harvest, timing, proliferation and culture conditions. Fibroblasts were exposed to 10^-7 M testosterone or 10^-7 M estrogen for 24 hours and either immunostained for collagen type I or subjected to ELISA.

Results

Results showed increased collagen staining in fibroblasts treated with testosterone compared to control and decreased staining with estrogen. ELISA results showed that testosterone increased collagen I by 20% whereas estrogen decreased collagen I by 15%.

Conclusion

Data demonstrates the usefulness of our cell model in studying the specific role of the adventitia apart from other blood vessel tissue in rat coronary arteries. Results suggest opposite effects of testosterone and estrogen on collagen synthesis in the rat coronary artery adventitial fibroblasts.     

Smoking cessation and bronchial epithelial remodelling in COPD: a cross-sectional study

Background

Chronic Obstructive Pulmonary Disease (COPD) is associated with bronchial epithelial changes, including squamous cell metaplasia and goblet cell hyperplasia. These features are partially attributed to activation of the epidermal growth factor receptor (EGFR). Whereas smoking cessation reduces respiratory symptoms and lung function decline in COPD, inflammation persists. We determined epithelial proliferation and composition in bronchial biopsies from current and ex-smokers with COPD, and its relation to duration of smoking cessation.

Methods

114 COPD patients were studied cross-sectionally: 99 males/15 females, age 62 ± 8 years, median 42 pack-years, no corticosteroids, current (n = 72) or ex-smokers (n = 42, median cessation duration 3.5 years), postbronchodilator FEV₁ 63 ± 9% predicted. Squamous cell metaplasia (%), goblet cell (PAS/Alcian Blue⁺) area (%), proliferating (Ki-67⁺) cell numbers (/mm basement membrane), and EGFR expression (%) were measured in intact epithelium of bronchial biopsies.

Results

Ex-smokers with COPD had significantly less epithelial squamous cell metaplasia, proliferating cell numbers, and a trend towards reduced goblet cell area than current smokers with COPD (p = 0.025, p = 0.001, p = 0.081, respectively), but no significant difference in EGFR expression. Epithelial features were not different between short-term quitters (<3.5 years) and current smokers. Long-term quitters (≥3.5 years) had less goblet cell area than both current smokers and short-term quitters (medians: 7.9% vs. 14.4%, p = 0.005; 7.9% vs. 13.5%, p = 0.008; respectively), and less proliferating cell numbers than current smokers (2.8% vs. 18.6%, p < 0.001).

Conclusion

Ex-smokers with COPD had less bronchial epithelial remodelling than current smokers, which was only observed after long-term smoking cessation (>3.5 years).

Trial registration

NCT00158847     

Female attractiveness affects paternal investment: experimental evidence for male differential allocation in blue tits

Introduction

The differential allocation hypothesis (DAH) predicts that individuals should adjust their parental investment to their current mate??s quality. Although in principle the DAH holds for both sexes, male adjustment of parental investment has only been tested in a few experimental studies, revealing contradictory results. We conducted a field experiment to test whether male blue tits (Cyanistes caeruleus) allocate their parental effort in relation to female ornamentation (ultraviolet colouration of the crown), as predicted by the DAH.

Results

We reduced the UV reflectance in a sample of females and compared parental care by their mates with that of males paired to sham-manipulated control females. As predicted by the DAH our results demonstrate that males paired with UV-reduced females invested less in feeding effort but did not defend the chicks less than males paired with control females.

Conclusions

To our knowledge, this is one of the first studies providing support for male differential allocation in response to female ornamentation.     

Ambulatory oxygen: why do COPD patients not use their portable systems as prescribed? A qualitative study

Background

In mechanically ventilated preterm infants with respiratory distress syndrome (RDS), exogenous surfactant application has been demonstrated both to decrease DNA-synthesis but also and paradoxically to increase epithelial cell proliferation. However, the effect of exogenous surfactant has not been studied directly on alveolar type II cells (ATII cells), a key cell type responsible for alveolar function and repair.

Objective

The aim of this study was to investigate the effects of two commercially available surfactant preparations on ATII cell viability and DNA synthesis.

Methods

Curosurf^® and Alveofact^® were applied to two ATII cell lines (human A549 and mouse iMATII cells) and to primary rat ATII cells for periods of up to 24 h. Cell viability was measured using the redox indicator resazurin and DNA synthesis was measured using BrdU incorporation.

Results

Curosurf^® resulted in slightly decreased cell viability in all cell culture models. However, DNA synthesis was increased in A549 and rat ATII cells but decreased in iMATII cells. Alveofact^® exhibited the opposite effects on A549 cells and had very mild effects on the other two cell models.

Conclusion

This study showed that commercially available exogenous surfactants used to treat preterm infants with RDS can have profound effects on cell viability and DNA synthesis.     

The effects of captivity on the electric organ discharge and plasma hormone levels in Gnathonemus petersii (Mormyriformes)

1. Experiment 1 employed a repeated measures design to examine the effects of captivity on sex differences in the electric organ discharge (EOD) of Gnathonemus petersii, newly imported from Africa, and maintained individually or in groups.
2. On the day of import, males exhibited longer durations of phases 2 and 3 of the EOD and lower peak power spectral frequencies (PPSFs) than females.
3. After 14 days in captivity in the laboratory, the sex differences were eliminated. After 37 days of captivity, all sex differences were still abolished, or even reversed depending on housing conditions. Males exhibited the most dramatic changes in EODs and females appeared to have higher testosterone (T) levels than males.
4. Experiment 2 was designed to investigate the effects of captivity on both behavior and endocrine status in 58 newly imported males. In this independent group design, EOD data and blood were collected from subjects over 15 days.
5. Decreases in phase 3 of the EOD and increases in PPSFs progressed over the 15 day experimental period, becoming statistically significant by days 10 and 15, respectively. Regardless of housing conditions, both T and 11-keto T dramatically decreased to near non-detectable levels by Day 5 in the laboratory.
6. Captivity causes rapid and profound changes in the endocrine system which result in dramatic changes in steroid-sensitive EODs. These findings directly link captivity, hormones, and behavior, and show why feral animals brought into captivity usually do not exhibit sexual behavior.

     

Strategies and methods to study sex differences in cardiovascular structure and function: a guide for basic scientists

Background

Cardiovascular disease remains the primary cause of death worldwide. In the US, deaths due to cardiovascular disease for women exceed those of men. While cultural and psychosocial factors such as education, economic status, marital status and access to healthcare contribute to sex differences in adverse outcomes, physiological and molecular bases of differences between women and men that contribute to development of cardiovascular disease and response to therapy remain underexplored.

Methods

This article describes concepts, methods and procedures to assist in the design of animal and tissue/cell based studies of sex differences in cardiovascular structure, function and models of disease.

Results

To address knowledge gaps, study designs must incorporate appropriate experimental material including species/strain characteristics, sex and hormonal status. Determining whether a sex difference exists in a trait must take into account the reproductive status and history of the animal including those used for tissue (cell) harvest, such as the presence of gonadal steroids at the time of testing, during development or number of pregnancies. When selecting the type of experimental animal, additional consideration should be given to diet requirements (soy or plant based influencing consumption of phytoestrogen), lifespan, frequency of estrous cycle in females, and ability to investigate developmental or environmental components of disease modulation. Stress imposed by disruption of sleep/wake cycles, patterns of social interaction (or degree of social isolation), or handling may influence adrenal hormones that interact with pathways activated by the sex steroid hormones. Care must be given to selection of hormonal treatment and route of administration.

Conclusions

Accounting for sex in the design and interpretation of studies including pharmacological effects of drugs is essential to increase the foundation of basic knowledge upon which to build translational approaches to prevent, diagnose and treat cardiovascular diseases in humans.     

Surfactant Protein D modulates allergen particle uptake and inflammatory response in a human epithelial airway model

Background

The obese-asthma phenotype is not well defined. The aim of this study was to examine both mechanical and inflammatory influences, by comparing lung function with body composition and airway inflammation in overweight and obese asthma.

Methods

Overweight and obese (BMI 28-40 kg/m²) adults with asthma (n = 44) completed lung function assessment and underwent full-body dual energy x-ray absorptiometry. Venous blood samples and induced sputum were analysed for inflammatory markers.

Results

In females, android and thoracic fat tissue and total body lean tissue were inversely correlated with expiratory reserve volume (ERV). Conversely in males, fat tissue was not correlated with lung function, however there was a positive association between android and thoracic lean tissue and ERV. Lower body (gynoid and leg) lean tissue was positively associated with sputum %neutrophils in females, while leptin was positively associated with android and thoracic fat tissue in males.

Conclusions

This study suggests that both body composition and inflammation independently affect lung function, with distinct differences between males and females. Lean tissue exacerbates the obese-asthma phenotype in females and the mechanism responsible for this finding warrants further investigation.