Sex Differences Research Articles

Reproduction, Diet, and Sexual Dimorphism in Micrablepharus atticolus (Squamata, Gymnophthalmidae) in Cerrado Enclaves Within Brazilian Amazon Forest

Reproduction, Diet, and Sexual Dimorphism in Micrablepharus atticolus (Squamata, Gymnophthalmidae) in Cerrado Enclaves Within Brazilian Amazon Forest

Reference genome provide insights into sex determination of silver aworana (Osteoglossum bicirrhosum)

BackgroundSilver arowana (Osteoglossum bicirrhosum) is a basal fish species with sexual monomorphism, while its sex determination mechanism has been poorly understood, posing a significant challenge to its captive breeding efforts.ResultsWe constructed two high-quality chromosome-level genome assemblies for both female and male silver arowana, with scaffold N50 values over 10 Mb. Combining re-sequencing data of 109 individuals, we identified a female-specific region, which was localized in a non-coding region, i.e., around 26-kb upstream of foxl2 gene (encoding forkhead box L2). Its strong interaction with the neighboring foxl2 on the same chromosome suggests foxl2 as a candidate sex-related gene in silver arowana. We subsequently propose a complex gene network in the sex determination process of silver arowana, with foxl2 acting as the central contributor. Transcriptome sequencing of gonads support our hypothesis that the regulation of foxl2 can be influenced by the spatial proximity of the female-specific fragment, thereby promoting ovarian function or inhibiting testicular function to stimulate gonadal differentiation. Furthermore, we found the sex chromosomes to be homomorphic with a potentially recent origin, as a linkage disequilibrium analysis proved minor recombination suppression.ConclusionsThese results taken together serve as a crucial foundation for conducting extensive investigations on the evolution and differentiation of sex-determining mechanisms, as well as the emergence and development of sex chromosomes in various fishes.

A Review of Sex and Gender Factors in Stimulant Treatment for ADHD: Knowledge Gaps and Future Directions.

Stimulant medications are the primary pharmacological intervention for ADHD, yet our understanding of how sex and gender impact stimulant treatment outcomes remains limited. Clinical guidelines do not differ for female and male individuals despite possible sex and gender-related differences in effectiveness, adverse events, and pharmacokinetics. This theoretical framework identifies five key knowledge gaps relating to sex and gender effects in stimulant treatment. We investigate the stimulant treatment trajectories of girls and women with ADHD from diagnosis and prescription to daily use and outcomes. We examine the impact of reproductive life transitions and hormonal fluctuations and their interactions with gender socialization and gendered expectations on treatment effectiveness, stigma, and adherence. By synthesizing existing literature, proposing testable predictions, and suggesting future research directions, we highlight the urgent need for studies that systematically investigate these factors. Addressing these gaps could significantly improve treatment outcomes for girls and women with ADHD, particularly during biological and gender role transitions.

Sex Differences in Circadian Timing and Biological Night in Adolescents.

Circadian rhythms, intrinsic 24-h cycles that drive rhythmic changes in behavior and physiology, are important for normal physiology and health. Previous work in adults has identified sex differences in circadian rhythms of melatonin, temperature, and the intrinsic period of the human circadian timing system. However, less is known about sex differences in circadian rhythms at other developmental stages. To address this gap, we considered a secondary analysis of sleep and circadian data from two studies involving adolescent participants during the academic year: (n = 32, 15 females). We collected 1 week of in-home actigraphy data to calculate sleep-wake parameters and in-laboratory salivary melatonin data collection in dim-light conditions was used to compute dim-light melatonin onset (DLMO) and offset (DLMOff) using a threshold of 4 pg/mL. We found that DLMO was an average of 96 min earlier, the time between DLMO and bedtime was an average of 56 min greater, and the biological night (time between DLMO and DLMOff) was 60 min longer in females compared to males, even though bedtimes and waketimes were not statistically different between the groups. In addition, after accounting for differences in bedtime, sex was still a significant predictor of DLMO. Conversely, no evidence was found indicating a difference in DLMOff or the phase angle between DLMOff and waketime by sex. These findings suggest that sex differences in circadian rhythms are present in adolescents and may have implications for circadian health during this important developmental period.

Aging and sex differences in salt sensitivity of blood pressure.

Salt sensitivity of blood pressure (SSBP) is a complex physiological trait characterized by changes in blood pressure in response to dietary salt intake. Aging introduces an additional layer of complexity to the pathophysiology of SSBP, with mitochondrial dysfunction, epigenetic modifications, and alterations in gut microbiota emerging as critical factors. Despite advancements in understanding these mechanisms, the processes driving increased salt sensitivity with age and their differential impacts across sexes remain unclear. This review explores the current understanding of salt sensitivity, delving into its underlying mechanisms, the role of inflammation, and the influence of aging and sex differences on these processes. We also aim to provide insights into the multifaceted nature of salt sensitivity and its implications for personalized treatment strategies in hypertension management.

School Attendance Among Autistic Students in Aotearoa/New Zealand: A Population Cross-Sectional StudyUsing the Integrated Data Infrastructure.

Extant literature indicates autistic students have lower school attendance compared to the general population. However, there remains considerable heterogeneity between studies, a lack of large population-based studies beyond the UK and US, and insufficient consideration of age and sex differences in attendance rates. The aim of this study was to examine school attendance among autistic compared with non-autistic students including stratification by age and sex. This was a national retrospective cohort study using population-level data on students aged 5 to 16 years in 2018. Autism was identified using diagnostic information contained within multiple health datasets. Regular attendance was defined as attending 90% or more of school half days. The association between autism and attendance was estimated using complete-case 2-level random intercept modified Poisson regression. Among 654 438 students, 8427 (1.3%) were autistic. In adjusted analyses, autism was associated with significantly decreased likelihood of regular attendance (incident rate ratio [IRR] 0.88; 95% CI, 0.86-0.90). Age and sex stratification revealed significant age differences with likelihood of regular school attendance lower for younger autistic students (5-11 years) (IRR 0.85; 95% CI, 0.83-0.87) while sex differences were marginal. The most frequent type of non-attendance among autistic students was justified (including medical) absence (8.2% of recorded attendance hours for autistic students vs. 5.0% for non-autistic students). This study provides further, whole-population evidence of the significant disparities experienced by Autistic students. To improve attendance of autistic students, comprehensive and targeted supports are required to help the student, family and school.

Sexual Dimorphism in the Downregulation of Extracellular Matrix Genes Contribute to Aortic Structural Stiffness in Female Mice.

The contribution of sex hormones to cardiovascular disease, including arterial stiffness, is established; however, the role of sex chromosome interaction with sex hormones, particularly in women, is lagging. Arterial structural stiffness depends on the intrinsic properties and transmural wall geometry that comprise a network of cells and extracellular matrix (ECM) proteins expressed in a sex-dependent manner. In this study, we used four-core genotype (FCG) mice to determine the relative contribution of sex hormones versus sex chromosomes or their interaction with arterial structural stiffness. Gonadal intact FCG mice included females (F) and males (M) with either XX or XY sex chromosomes (n=9-11/group). We isolated the thoracic aorta, and a tissue puller was used to assess structural resistance to changes in shape under control, collagenase, or elastase conditions. We determined histological collagen area fraction and evaluated aortic ECM genes by PCR microarrays followed by RT-qPCR. Stress-strain curves showed higher elastic modulus (P<0.001), denoting decreased extensibility in XXF compared to XYF aortas, which were significantly reversed by collagenase and elastase treatments (P<0.01). Aortic gene expression analysis indicated a significant reduction in Emilin1, Thbs2, and Icam1 in the XXF versus XYF aorta (P<0.05). Uniaxial stretching of XXF aortic vascular smooth muscle cells indicated decreased Thbs2, Ctnna1, and Ecm1 genes. We observed a significant (P<0.05) reduction in Masson's trichrome staining in collagenase but not elastase-treated aortic rings compared to the control. The increased aortic elastic modulus in XXF compared to XYF mice suggests a decrease in aortic extensibility mediated by a reduction in ECM genes.

Sexual dimorphism in right ventricular adaptation to pressure overload involves differential angiogenic response.

This study investigated the sexual dimorphism in right ventricle (RV) remodeling in right heart failure susceptible Fischer CDF rats using the pulmonary artery banding (PAB) model. Echocardiography and hemodynamic measurements were performed in adult male and female Fischer CDF rats at 1- or 2-weeks post-PAB. RV systolic pressure and RV hypertrophy were significantly elevated in PAB rats compared to sham control at 1- and 2-weeks post-PAB; however, no differences were observed between male and female rats. Increase in cardiomyocyte cross-sectional area and RV end-diastolic diameter was observed in male rats compared to female rats at 2-weeks post-PAB. Conversely, higher fractional area change and cardiac index were observed in female rats compared to male rats at 2-weeks post-PAB. To explore the mechanisms, a focused PCR array was performed and higher expression of angiogenic genes, including sphingosine kinase-1 (Sphk1), was observed in the RV of female rats compared to male rats. Consistent with the higher angiogenic gene expression, female rats had a higher RV vascular density at 2-weeks post-PAB compared to male rats. Female RV endothelial cells (RVEC) had better angiogenic ability compared to male cells that was potentiated by estradiol. Furthermore, effect of estradiol on RVEC was inhibited by Sphk1 inhibitor (PF-543). Together, female Fischer CDF rats develop adaptive RV remodeling post-PAB compared to mal-adaptive remodeling in male rats. Moreover, the adaptive remodeling in female rats is associated with better RV angiogenic response that may result from better angiogenic ability of female RVEC and proangiogenic effects of estradiol through Sphk1.

A new species of catfish, Pterocryptis vorax (Actinopterygii: Siluridae), from northern Borneo

This study describes Pterocryptis vorax, a new species of silurid catfish from the upper reaches of the Temburong River drainage in Brunei Darussalam, northern Borneo. Pterocryptis vorax is distinguished from congeners in having a unique combination of the following characters: rictal lobe ending at vertical posterior to posterior orbital margin, deep lower jaw with a more gently curved anteroventral margin, a color pattern of densely distributed dark brown patches on the flanks that coalesce to form a reticulate pattern, a dark vertical band at the caudal-fin base, 46–57 anal-fin rays and 48–49 vertebrae. Sexual dichromatism in Pterocryptis is also reported for the first time here.

Heme oxygenase, biliverdin reductase, and bilirubin pathways regulate oxidative stress and insulin resistance: a focus on diabetes and therapeutics.

Metabolic and insulin-resistant diseases, such as type 2 diabetes mellitus (T2DM), have become major health issues worldwide. The prevalence of insulin resistance in the general population ranges from 15.5% to 44.6%. Shockingly, the global T2DM population is anticipated to double by 2050 compared with 2021. Prior studies indicate that oxidative stress and inflammation are instrumental in causing insulin resistance and instigating metabolic diseases. Numerous methods and drugs have been designed to combat insulin resistance, including metformin, thiazolidinediones (TZDs), sodium-glucose cotransporter 2 inhibitors (SGLT2i), glucagon-like peptide 1 receptor agonists (GLP1RA), and dipeptidyl peptidase 4 inhibitors (DPP4i). Bilirubin is an antioxidant with fat-burning actions by binding to the PPARα nuclear receptor transcription factor, improving insulin sensitivity, reducing inflammation, and reversing metabolic dysfunction. Potential treatment with antioxidants like bilirubin and increasing the enzyme that produces it, heme oxygenase (HMOX), has also gained attention. This review discusses the relationships between bilirubin, HMOX, and insulin sensitivity, how T2DM medications affect HMOX levels and activity, and potentially using bilirubin nanoparticles to treat insulin resistance. We explore the sex differences between these treatments in the HMOX system and how bilirubin levels are affected. We discuss the emerging concept that bilirubin bioconversion to urobilin may have a role in metabolic diseases. This comprehensive review summarizes our understanding of bilirubin functioning as a hormone, discusses the HMOX isoforms and their beneficial mechanisms, analyzes the sex differences that might cause a dichotomy in responses, and examines the potential use of HMOX and bilirubin nanoparticle therapies in treating metabolic diseases.

Gender Differences in Cardiovascular Events among Patients with Sleep Apnoea Syndrome: A Real-World Data Analysis of a Nationwide Epidemiological Dataset.

Sleep apnoea syndrome (SAS) is a common sleep disorder associated with heightened cardiovascular risks, yet sex-specific differences in these risks remain unclear. This retrospective observational cohort study utilized the JMDC Claims Database, covering >5 million individuals in Japan. We analyzed data from 4,173,702 individuals (2,406,930 men, 1,766,772 women) after excluding those with central SAS, cardiovascular disease, and incomplete lifestyle questionnaire data. SAS was identified using ICD-10 codes and treatment records. Cox regression models adjusted for multiple factors examined the association between SAS and cardiovascular outcomes. Among the participants, 39,078 men (1.62%) and 3,960 women (0.22%) were diagnosed with SAS. Over a mean follow-up of 1,290±1,000 days, SAS was associated with an increased risk of composite cardiovascular events, with a hazard ratio (HR) of 1.27 (95% CI, 1.23-1.31) in men and 1.72 (95% CI, 1.54-1.92) in women compared to those without SAS. The association was significantly stronger in women than in men (P-value for interaction< 0.001) and this sex difference was validated by various sensitivity analyses. Despite the lower prevalence of SAS among women, there was a gender disparity in the cardiovascular impact of SAS, with women demonstrating a significantly higher risk compared to men. This underscores the importance of tailored management strategies aimed at early detection and cardiovascular disease prevention specifically in female patients with SAS.

Parental Drinking Patterns and Adolescent Alcohol Consumption: Considering the Role of Sex and Developmental Stage.

Research indicates that parental behaviors shape adolescents' alcohol consumption, but it is unclear whether mothers or fathers have a more significant impact and how this relationship varies by sex and developmental stage. This study examines the effects of parental alcohol consumption patterns on adolescents in Russia using a large representative sample. The study employs pooled data from the Russia Longitudinal Monitoring Survey-Higher School of Economics (RLMS-HSE) from 2006 to 2019. The final sample included 25 611 cases of adolescents with the available data on their parents (20% male adolescents aged 14-17, 20% female adolescents aged 14-17, 28% male adolescents aged 18-22, and 32% female adolescents aged 18-22; M = 18.22, SD = 2.63). Logistic regression models were used to account for sex and developmental stages. Adolescent drinking was measured as a binary variable indicating drinking at least sometimes, while parental drinking was categorised into five levels, including moderate and excessive consumption. Maternal alcohol consumption patterns were associated with adolescent drinking. Sex differences were observed, with parental drinking patterns showing a greater association with alcohol use for female adolescents. For middle adolescents, a positive association with excessive alcohol consumption by their parents was found. The study emphasises the importance of considering both parents' alcohol consumption patterns when examining adolescent alcohol use, with findings indicating that maternal drinking played a more significant role than paternal drinking. It is crucial to explore this relationship separately for male and female adolescents, considering the stage of adolescence.

Gender-/Sex-Specific Differences in Clinical Trials in Uro-Oncology

Subgroup analyses in clinical trials sometimes reveal gender-/sex-dependent differences in cancer outcomes. However, drug approvals are rarely restricted to a specific sex or gender, and recommendations regarding dosage are rarely tailored accordingly. Furthermore, discrepancies exist between the gender-/sex-dependent enrollment rates in clinical trials and real-world incidence or mortality rates. This article highlights gender-/sex differences in clinical trials in uro-oncology.

Sex Differences in Textbook Outcomes among Adults Undergoing Elective Abdominal Aortic Aneurysm Repair

Sex Differences in Textbook Outcomes among Adults Undergoing Elective Abdominal Aortic Aneurysm Repair

Sex Differences in Early/Unplanned Separation Among US Service Members With a History of Mild Traumatic Brain Injury.

To investigate the incidence of early/unplanned (E/U) separations following mild traumatic brain injury (mTBI) and assess whether sex impacts the hazard of separation. Military Health System (MHS). Active duty service members (N=75,730) with an initial mTBI diagnosis in military records between January 2011 and January 2018. Retrospective cohort study of electronic health records in the MHS. Cause-specific Cox proportional hazards models were used with sex at birth as the primary predictor. Early/unplanned (E/U) separation, defined as military separation attributed to disability, misconduct, poor performance, death, or other medical circumstances, within 2 years following the initial mTBI. Incidence of E/U separation within 2 years following mTBI was 13.7% (11.0% in women and 14.2% in men). Disability and misconduct separations were most common. Female service members had lower adjusted hazards for any E/U separation (Hazard Ratio [HR]=0.65; 95% Confidence Interval [CI]: 0.61,0.69), disability separation (HR=0.71; 95% CI: 0.65, 0.78), misconduct separation (HR=0.40; 95% CI: 0.36, 0.45), and poor performance separation (HR=0.84; 95% CI: 0.72, 0.99), compared to males, but had higher adjusted hazards for separations due to other medical circumstances (HR=1.24; 95% CI: 1.04, 1.48). Male and female service members had different hazards of E/U separation following mTBI. Separating early may increase the risk of adverse health and socioeconomic outcomes, so additional research is needed on why these separations occur and why they may be impacting men and women differently.

Brain volume metric analysis is correlated with aging changes and sex differences in Thai older adults

Introduction: Normative data on structural brain volume changes with age and sex differences are required as a reference standard for future research and clinical use. Methods: We studied a two-center, metropolitan-based, prospective cohort of adults aged fifty-five years and older who were recruited from community-dwelling settings and outpatient clinics without cognitive impairment at baseline and who were followed up for 2 years. The clinical data, neuropsychological tests, and brain MRI obtained with FreeSurfer software were utilized for quantitative volumetric measurements. Results: A total of 296 participants were recruited at the beginning, with 17 participants (5.8%, excluding 2 subjects with claustrophobia) excluded due to abnormal MRI findings and 27 participants (9.1%) excluded due to MCI/dementia. Among the 250 remaining, 14 patients dropped out or were lost to follow-up, and 35 had MCI or AD converters (14.8%). The remaining 201 subjects with normal cognitive function aged 55-85 years were analyzed for structural brain volume. There were significant correlations between age and brain parameters, including the hippocampus, corpus callosum, thalamus and ventricular volume changes (p value &lt; 0.05). There were significant differences between males and females in total intracranial volume, caudate, temporal lobe, and ventricle volumes in subjects aged 65–74 years, and in total intracranial volume and ventricle volumes in subjects aged 55–64 years (p value &lt; 0.05). Conclusion: Age and sex contributed to differences in brain structure and ventricular volume. These data could be used as a normative reference for clinical interpretation in people up to 85 years old and for understanding the physiological aging-related changes in the brain.

The lymphocyte levels of Hashimoto thyroiditis patients were significantly lower than that of healthy population

Background and purposeHashimoto thyroiditis (HT) is an autoimmune disease without infectivity. We compared the differences of blood lymphocytes levels between HT patients and healthy people.Patients and methodsThis study included a total of 84 HT patients whose thyroid function was normal and 60 HT patients with abnormal thyroid function. A corresponding number of medical examination population in our hospital were randomly selected as the control groups. White blood cell count, neutrophil count, neutrophil percentage, lymphocyte count, and lymphocyte percentage were compared between HT patients and healthy population. The correlations between TSH, FT4 and above parameters were further tested.ResultsWe found significant differences between HT with normal thyroid function group and control group in lymphocyte count (P&amp;lt;0.001), lymphocyte percentage (P&amp;lt;0.001) and neutrophil percentage (P&amp;lt;0.001), but no differences in sex (P=0.134), age (P=0.200), white blood cell count (P=0.315) and neutrophil count (P=0.790). Significant differences were observed in neutrophil count (P=0.032), neutrophil percentage (P=0.010), lymphocyte count (P=0.010) and lymphocyte percentage (P&amp;lt;0.001) between HT with abnormal thyroid function group and control group, but not in sex (P=0.769), age (P=0.060) and white blood cell count (P=0.156) between the two groups. There were significant differences in white blood cell count (P=0.009) and neutrophil count (P=0.032) between HT patients in the normal thyroid function group and HT patients in the abnormal thyroid function group. Neither FT4 nor TSH was associated with lymphocyte levels or neutrophil levels.ConclusionsThe lymphocyte levels in HT patients were significantly lower than healthy population. The neutrophil count in HT patients with regular thyroid function was lower than those in abnormal thyroid function HT patients.

Sex differences in the metabolism of glucose and fatty acids by adipose tissue and skeletal muscle in humans.

Adult males and females have markedly different body composition, energy expenditure, and have different degrees of risk for metabolic diseases. A major aspect of metabolic regulation involves the appropriate storage and disposal of glucose and fatty acids. The use of sophisticated calorimetry, tracer, and imaging techniques have provided insight into the complex metabolism of these substrates showing that the regulation of these processes varies tremendously throughout the day, from the overnight fasting condition to meal ingestion, to the effects of physical activity. The sexual dimorphism in substrate metabolism is most readily observed in how fatty acids are stored and mobilized. The objective of this review is to provide a comprehensive and critical summary of the reported sex-differences in the mobilization, oxidation and storage of fat and carbohydrate in adipose tissue and skeletal muscle. We will describe how adipose tissue lipolysis differs between sexes, and how this varies between fed, fasted and exercise conditions. We will also review what is known about endogenous and exogenous fatty acid storage in adipose tissue and muscle, as well as how oxidation compares between men and women in response to exercise. What has been learned about the cellular level regulation of these processes will be described. Although glucose metabolism exhibits fewer differences between men and women, we will also review the existing knowledge on this topic.

Preferences for facial femininity/masculinity across culture and the sexual orientation spectrum.

Judgments of attractiveness have many important social outcomes, highlighting the need to understand how people form these judgments. One aspect of appearance that impacts perceptions of attractiveness is facial femininity/masculinity (sexual dimorphism). However, extant research has focused primarily on White, Western, heterosexual participants' preferences for femininity/masculinity in White faces, limiting generalizability. Indeed, recent research indicates that these preferences vary by culture, and other work finds differences between gay/lesbian and heterosexual individuals. Aspects of identity, such as culture and sexual orientation, do not exist in isolation from one another but rather intersect, leaving a critical gap in understanding. Our research therefore bridged across these hitherto separate areas of inquiry to provide a more comprehensive understanding of facial femininity/masculinity preferences. We tested how White British and East Asian Japanese individuals' culture and sexual orientation (including, crucially, bisexual individuals) predict their femininity/masculinity preferences for White and East Asian women's and men's faces, using two experimental tasks (forced-choice, interactive). Results show that individuals' culture and sexual orientation consistently interact to predict their preferences for femininity/masculinity in women's and men's faces, and we furthermore reveal bisexual individuals' preferences to differ from those of other sexual orientations. We also find differences between experimental tasks, with greater preferences for femininity emerging in the interactive task compared to the forced-choice task. Altogether, our findings highlight the importance of considering intersecting identities, consequences of methods of measurement, and shortcomings of extant explanations for preferences for facial femininity/masculinity. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

Changes in the shape of the lumbar curve during growth : a geometric morphometric approach.

The development of lumbar lordosis has been traditionally examined using angular measurements of the spine to reflect its shape. While studies agree regarding the increase in the angles during growth, the growth rate is understudied, and sexual dimorphism is debated. In this study, we used a novel method to estimate the shape of the lumbar curve (LC) using the landmark-based geometric morphometric method to explore changes in LC during growth, examine the effect of size and sex on LC shape, and examine the associations between angular measurements and shape. The study population included 258 children aged between 0 and 20 years (divided into five age groups) who underwent a CT scan between the years 2009 and 2019. The landmark-based geometric morphometric method was used to capture the LC shape in a sagittal view. Additionally, the lordosis was measured via Cobb and sacral slope angles. Multivariate and univariate statistical analyses were carried out to examine differences in shape between males and females and between the age groups. The overall shape of the LC overlapped between males and females in most age groups, except for the nine- to 12-year age group. However, size did not affect LC shape. LC shape changed significantly during growth from straight to curved, reaching its mature shape earlier in females. This corresponded with the results obtained by the lordosis and sacral slope angles. A significant positive correlation was found between the LC shape and angles, although the angles demonstrated poor distinction between age groups, as opposed to the LC shape. New insights into LC shape development were achieved using the geometrical morphometric method. The LC shape was sex-independent in most age groups. However, the LC reached its mature shape earlier in females than males. The method and data of this study are beneficial for future studies examining aetiological factors for spinal pathologies and maldevelopment.