Sex as a Biological Variable: A 5-Year Progress Report and Call to Action

Sex differences in human performance

Sex as a biological variable is an underappreciated aspect of biomedical research, with its importance emerging in more recent years. This review assesses the current understanding of sex differences in human physical performance. Males outperform females in many physical capacities because they are faster, stronger and more powerful, particularly after male puberty. This review highlights key sex differences in physiological and anatomical systems (generally conferred via sex steroids and puberty) that contribute to these sex differences in human physical performance. Specifically, we address the effects of the primary sex steroids that affect human physical development, discuss insight gained from an observational study of 'real-world data' and elite athletes, and highlight the key physiological mechanisms that contribute to sex differences in several aspects of physical performance. Physiological mechanisms discussed include those for the varying magnitude of the sex differences in performance involving: (1) absolute muscular strength and power; (2) fatigability of limb muscles as a measure of relative performance; and (3) maximal aerobic power and endurance. The profound sex-based differences in human performance involving strength, power, speed and endurance, and that are largely attributable to the direct and indirect effects of sex-steroid hormones, sex chromosomes and epigenetics, provide a scientific rationale and framework for policy decisions on sex-based categories in sports during puberty and adulthood. Finally, we highlight the sex bias and problem in human performance research of insufficient studies and information on females across many areas of biology and physiology, creating knowledge gaps and opportunities for high-impact studies.

Cardiorespiratory Fitness as a Predictor of Non-Cardiovascular Disease and Non-Cancer Mortality in Men

OBJECTIVE

To evaluate the association of 5 major cause-specific non-cardiovascular disease (CVD) and non-cancer deaths with cardiorespiratory fitness (CRF).

METHODS

Patients were 36,645 men (43.3±9.3 years) free of known CVD and cancer at baseline who completed a maximal treadmill graded exercise test during a preventive examination at the Cooper Clinic (Dallas, Texas) between 1971 and 2003. CRF was quantified as maximal treadmill exercise test duration and grouped as low (referent), moderate, and high. Cause-specific non-CVD non-cancer deaths were (1) diabetes or kidney disease, (2) chronic respiratory disease, (3) acute respiratory and infectious disease, (4) injuries, and (5) other non-CVD non-cancer deaths.

RESULTS

A total of 694 non-CVD non-cancer deaths occurred during an average of 17 years of follow-up. After adjustment for covariates, hazard ratios (95% confidence intervals) for moderate and high CRF, respectively, were 0.57 (0.47 to 0.69) and 0.43 (0.34 to 0.54) for overall non-CVD non-cancer deaths (P<.0001); 0.39 (0.28 to 0.54) and 0.17 (0.10 to 0.28) for diabetes or kidney disease (P<.001); 0.36 (0.22 to 0.59) and 0.09 (0.04 to 0.20) for chronic respiratory diseases (P<.001 for all); 0.74 (0.47 to 1.16) and 0.34 (0.19 to 0.61) for acute respiratory and infectious diseases (P<.01 for both); and 0.48 (0.35 to 0.66) and 0.38 (0.26 to 0.55) for any other non-CVD non-cancer deaths (P<.0001 for both).

CONCLUSION

Higher levels of CRF were significantly associated with lower risk of mortality from the 5 major non-CVD non-cancer causes. These results suggest that improvement in CRF may reduce non-CVD non-cancer deaths, which account for a significant proportion of adult mortality.

Exploring heterogeneity: a dive into preclinical models of cancer cachexia

Cancer cachexia (CC) is a multifactorial and complex syndrome experienced by up to 80% of patients with cancer and implicated in ∼40% of cancer-related deaths. Given its significant impact on patients' quality of life and prognosis, there has been a growing emphasis on elucidating the underlying mechanisms of CC using preclinical models. However, the mechanisms of cachexia appear to differ across several variables including tumor type and model and biologic variables such as sex. These differences may be exacerbated by variance in experimental approaches and data reporting. This review examines literature spanning from 2011 to March 2024, focusing on common preclinical models of CC, including Lewis Lung Carcinoma, pancreatic KPC, and colorectal colon-26 and Apcmin/+ models. Our analysis reveals considerable heterogeneity in phenotypic outcomes, and investigated mechanisms within each model, with particular attention to sex differences that may be exacerbated through methodological differences. Although searching for unified mechanisms is critical, we posit that effective treatment approaches are likely to leverage the heterogeneity presented by the tumor and pertinent biological variables to direct specific interventions. In exploring this heterogeneity, it becomes critical to consider methodological and data reporting approaches to best inform further research.

Integrating gender analysis into research: reflections from the Gender-Net Plus workshop

Gender equality has been a crosscutting issue in Horizon 2020 with three objectives: gender balance in decision-making, gender balance and equal opportunities in project teams at all levels, and inclusion of the gender dimension in research and innovation content. Between 2017 and 2022, the EU funded, in collaboration with national agencies, 13 transnational projects under "GENDER-NET Plus" that explored how to best integrate both sex and gender into studies ranging from social sciences, humanities, and health research. As the projects neared completion, forty researchers from these interdisciplinary teams met in November 2022 to share experiences, discuss challenges, and consider the best ways forward to incorporate sex and gender in research. Here, we summarize the reflections from this workshop and provide some recommendations for i) how to plan the studies (e.g., how to define sex and/or gender and their dimensions, rationale for the hypotheses, identification of data that can best answer the research question), ii) how to conduct them (e.g., adjust definitions and dimensions, perform pilot studies to ensure proper use of terminology and revise until consensus is achieved), and iii) how to analyze and report the findings being mindful of any real-world impact.

Modulation of Human Macrophages by Plasma from COVID-19 Patients Following BCG Vaccination: BATTLE Trial

Purpose

To analyze the interfering effect of plasma from COVID-19 convalescent adults vaccinated or not with intradermal Bacillus Calmette-Guérin (BCG) on human macrophages.

Methods

The BATTLE clinical trial (NCT04369794) was initiated in the 2020 SARS-CoV-2 pandemic to study the safety and efficacy of BCG revaccination of COVID-19 convalescent adults. We measured the expression induction of eleven COVID-19-related genes in human macrophages cultured in plasma taken from 22 BCG vaccinated and 17 placebo patients at baseline and 45 days post-intervention. Subgroup analysis was based on gender, age, job type (healthcare worker [HCW] vs non-HCW), and the presence of anosmia/dysgeusia.

Results

Compared to plasma from placebo counterparts, the plasma of BCG vaccinated patients increased the expression induction of interferon (IFN)β-1b (p = 0.042) in human macrophages. This increase was more pronounced in females and in healthcare workers (HCW) (p = 0.007 and 0.001, respectively). Interferon-induced transmembrane protein 3 (IFITM3) expression induction was increased by plasma from BCG vaccinated females, young age group, and HCWs (p = 0.004, 0.011, and 0.040, respectively). Interleukin (IL)-10 induction increased by the plasma of young BCG recipients (p = 0.008). Induction of IL-6 expression increased by non-HCW BCG recipients plasma but decreased by HCW BCG recipients plasma (p = 0.005). Baseline plasma of patients who presented with anosmia/dysgeusia at the time of admission induced lower angiotensin-converting enzyme 2 (ACE2) compared to those without the symptom (0.76 vs 0.97, p = 0.004). ACE2 expression induction significantly increased by plasma of BCG recipients if they had anosmia/dysgeusia on admission (p = 0.028).

Conclusion

The expressions of IFNβ-1b, IFITM3, IL-6, and IL-10 in human macrophages incubated with the plasma of COVID-19 convalescent patients were modulated by BCG. These modulations depended on subject-specific characteristics, including gender, age, clinical presentation (anosmia/dysgeusia), job type, and previous exposure to mycobacteria.

Rényi entropy-complexity causality space: a novel neurocomputational tool for detecting scale-free features in EEG/iEEG data

Scale-free brain activity, linked with learning, the integration of different time scales, and the formation of mental models, is correlated with a metastable cognitive basis. The spectral slope, a key aspect of scale-free dynamics, was proposed as a potential indicator to distinguish between different sleep stages. Studies suggest that brain networks maintain a consistent scale-free structure across wakefulness, anesthesia, and recovery. Although differences in anesthetic sensitivity between the sexes are recognized, these variations are not evident in clinical electroencephalographic recordings of the cortex. Recently, changes in the slope of the power law exponent of neural activity were found to correlate with changes in Rényi entropy, an extended concept of Shannon's information entropy. These findings establish quantifiers as a promising tool for the study of scale-free dynamics in the brain. Our study presents a novel visual representation called the Rényi entropy-complexity causality space, which encapsulates complexity, permutation entropy, and the Rényi parameter q. The main goal of this study is to define this space for classical dynamical systems within theoretical bounds. In addition, the study aims to investigate how well different time series mimicking scale-free activity can be discriminated. Finally, this tool is used to detect dynamic features in intracranial electroencephalography (iEEG) signals. To achieve these goals, the study implementse the Bandt and Pompe method for ordinal patterns. In this process, each signal is associated with a probability distribution, and the causal measures of Rényi entropy and complexity are computed based on the parameter q. This method is a valuable tool for analyzing simulated time series. It effectively distinguishes elements of correlated noise and provides a straightforward means of examining differences in behaviors, characteristics, and classifications. For the iEEG experimental data, the REM state showed a greater number of significant sex-based differences, while the supramarginal gyrus region showed the most variation across different modes and analyzes. Exploring scale-free brain activity with this framework could provide valuable insights into cognition and neurological disorders. The results may have implications for understanding differences in brain function between the sexes and their possible relevance to neurological disorders.

Relationship of Handgrip Strength and Asymmetry with Walking Ability in Older Adults with Excess Adiposity

When low muscle mass and impaired strength and physical function coexist with excess adiposity, it is termed sarcopenic obesity (SO). Handgrip strength (HGS) is a predictor of disability and mortality. Asymmetry in HGS, particularly ≥ 10% strength differences between hands, may indicate neuromuscular dysfunction observable prior to declines in maximal strength are detectedand therefore could be incorporated to identify those at risk of physical limitations and SO. This study compares HGS values and asymmetry in older adults with excess adiposity and evaluates their relationships with physical function. Baseline data from two previous pilot weight loss studies in 85 older adults with body mass index values ≥ 30 kg m-2 are included with measures of body composition, walking speed, and chair stand ability. Sixty-three participants met the criteria for SO. HGS correlated to gait speed (r = 0.22), distance walked (r = 0.40), chair stand time for 5 repetitions (r = 0.42) and during 30 s (r = 0.31). HGS asymmetry is only correlated to gait speed (r = 0.31) and there are no differences in physical function between those with and without asymmetry. Maximal HGS tests should continue to be used to screen for functional decline and disability.

Hormonal contraceptives and behavior: Updating the potent state of the nascent science

Hundreds of millions of people worldwide use hormonal contraceptives (HCs), which have been an essential part of women's reproductive health care for decades. Throughout that time, however, research on the neural and behavioral consequences of HCs was minimal and plagued by poor methodology. HC effects - and users - were assumed to be homogenous. Fortunately, there has been a recent upswell in the number and quality of investigations, affording tentative conclusions about the roles of HCs in spatial cognition and mental health, particularly depression. Thus, this paper leverages findings from the past few years to highlight the heterogeneous aspects of use that seem to matter for behavior - ranging from variation in hormonal contraceptive formulations and routes of administration to individual differences among users linked to age and reproductive health history. This paper closes with five tips for future research that will help capture and clarify heterogeneity in potential relations between HCs and behavior, namely data collection, regional access, lifespan factors, gender, and collaboration. HCs are sociopolitically provocative and research on their potential behavioral neuroendocrine impacts is becoming increasingly popular. It is, therefore, imperative for scientists to conduct replicable and robust empirical investigations, and to communicate findings with the nuance that the heterogeneity among users and effects requires.

Inclusion of Sex and Gender to Improve the State of the Science in Women's Health

ABSTRACT

The influence of sex and gender-related factors on health and disease at all levels of scale, across all health conditions, and throughout the entire life course is increasingly clear. A series of policies instituted by the National Institutes of Health (NIH) that require researchers to include appropriate populations and to analyze the data accordingly have strengthened the evidence base around the health of women. Translating these advances to the entire research ecosystem can catalyze rigorous biomedical discovery that can improve health. We encourage journals, publishers, and funders to align their policies and expectations regarding sex and gender considerations in research with those of the NIH and other international funding agencies.

Potential Differences in Psychedelic Actions Based on Biological Sex

The resurgence of interest in psychedelics as treatments for psychiatric disorders necessitates a better understanding of potential sex differences in response to these substances. Sex as a biological variable (SABV) has been historically neglected in medical research, posing limits to our understanding of treatment efficacy. Human studies have provided insights into the efficacy of psychedelics across various diagnoses and aspects of cognition, yet sex-specific effects remain unclear, making it difficult to draw strong conclusions about sex-dependent differences in response to psychedelic treatments. Compounding this further, animal studies used to understand biological mechanisms of psychedelics predominantly use one sex and present mixed neurobiological and behavioral outcomes. Studies that do include both sexes often do not investigate sex differences further, which may hinder the translation of findings to the clinic. In reviewing sex differences in responses to psychedelics, we will highlight the direct interaction between estrogen (the most extensively studied steroid hormone) and the serotonin system (central to the mechanism of action of psychedelics), and the potential that estrogen-serotonin interactions may influence the efficacy of psychedelics in female participants. Estrogen influences serotonin neurotransmission by affecting its synthesis and release, as well as modulating the sensitivity and responsiveness of serotonin receptor subtypes in the brain. This could potentially influence the efficacy of psychedelics in females by modifying their therapeutic efficacy across menstrual cycles and developmental stages. Investigating this interaction in the context of psychedelic research could aid in the advancement of therapeutic outcomes, especially for conditions with sex-specific prevalence.

A Semiautomated Protocol Towards Quantifying Vocal Effort in Relation to Vocal Performance During a Vocal Loading Task

To increase the reliability and comparability of vocal loading studies, this paper proposes the use of a standardized approach with experiments that are [1] grounded on consistent definitions of terms related to vocal fatigue (vocal effort, vocal demand, and vocal demand response), and [2] designed to reduce uncertainty and increase repeatability. In the approach, a semi-automated vocal loading task that also increases efficiencies in collecting and preparing vocal samples for analysis was used to answer the following research question: To what extent is vocal effort and vocal demand response sensitive to changes in vocal demands (ie, noise only, noise plus duration)? Results indicate that the proposed protocol design consistently induced change in both vocal effort and vocal demand response, indicating vocal fatigue. The efficacy of future vocal loading studies would be improved by adopting a more consistent methodology for quantifying vocal fatigue, thus increasing interstudy comparability of results and conclusions.

Long-read RNA sequencing identifies region- and sex-specific C57BL/6J mouse brain mRNA isoform expression and usage

Alternative splicing (AS) contributes to the biological heterogeneity between species, sexes, tissues, and cell types. Many diseases are either caused by alterations in AS or by alterations to AS. Therefore, measuring AS accurately and efficiently is critical for assessing molecular phenotypes, including those associated with disease. Long-read sequencing enables more accurate quantification of differentially spliced isoform expression than short-read sequencing approaches, and third-generation platforms facilitate high-throughput experiments. To assess differences in AS across the cerebellum, cortex, hippocampus, and striatum by sex, we generated and analyzed Oxford Nanopore Technologies (ONT) long-read RNA sequencing (lrRNA-Seq) C57BL/6J mouse brain cDNA libraries. From > 85 million reads that passed quality control metrics, we calculated differential gene expression (DGE), differential transcript expression (DTE), and differential transcript usage (DTU) across brain regions and by sex. We found significant DGE, DTE, and DTU across brain regions and that the cerebellum had the most differences compared to the other three regions. Additionally, we found region-specific differential splicing between sexes, with the most sex differences in DTU in the cortex and no DTU in the hippocampus. We also report on two distinct patterns of sex DTU we observed, sex-divergent and sex-specific, that could potentially help explain sex differences in the prevalence and prognosis of various neurological and psychiatric disorders in future studies. Finally, we built a Shiny web application for researchers to explore the data further. Our study provides a resource for the community; it underscores the importance of AS in biological heterogeneity and the utility of long-read sequencing to better understand AS in the brain.

Sex Differences in the Association of Depression Symptoms and Cardiovascular Disease in Adults in the United States

PURPOSE

This study explores the relationship between depression and cardiovascular disease (CVD) in the US adult population, focusing on sex differences.

DESIGN

Cross-sectional study.

SETTING

National Health and Nutrition Examination Survey data (2013-2018).

PARTICIPANTS

A total of 14 699 community-dwelling adults (≥20 years).

MEASURE

The Patient Health Questionnaire (PHQ-9) depression screening tool assessed depressive symptoms. CVD events included heart failure, coronary heart disease, angina, heart attack, or stroke.

ANALYSIS

Adjusted prevalence ratios were estimated using a Poisson regression model.

RESULTS

The study finds a positive association between CVD incidents and both mild to moderate depressive symptoms (aPR:1.42, P = .002) and moderately severe to severe depression (aPR:1.72, P = .024). Overall, females exhibit a 47% lower likelihood of CVD incidents compared to males. However, in a subgroup analysis, increased depressive symptoms correlate with higher CVD incidents in females (aPRs range: 2.09 to 3.43, P < .001) compared to males (aPRs range: 1.45 to 1.77, P < .001).

CONCLUSION

Depression is associated with increased cardiovascular disease (CVD) risk. Females generally have a lower CVD risk than males, but more severe depressive symptoms elevate CVD risk in females. These findings emphasize the significance of considering sex differences. Further research is needed to understand the underlying mechanisms.

Sex Disparities After Coronary Artery Bypass Grafting and Hospital Quality

Importance

Concern has been raised about persistent sex disparities after coronary artery bypass grafting, with female patients having higher mortality. However, whether these disparities persist across hospitals of different qualities is unknown.

Objective

To evaluate sex disparities in 30-day mortality after coronary artery bypass grafting across high- and low-quality hospitals.

Design, Setting, and Participants

This cross-sectional, retrospective cohort study evaluated Medicare beneficiaries undergoing coronary artery bypass grafting between October 1, 2015, and March 31, 2020. Data analysis was performed from July 1, 2023, to December 1, 2023.

Exposures

The primary exposures were hospital quality and sex. For hospital quality, hospitals were placed into rank order by their overall risk-adjusted mortality rate and divided into quintiles.

Main Outcome and Measures

Risk-adjusted 30-day mortality using a logistic regression model accounting for patient factors, including sex, age, comorbidities, elective vs unplanned admission, number of bypass grafts, use of arterial graft, and year of surgery.

Results

A total of 444 855 beneficiaries (mean [SD] age, 71.5 [7.5] years; 120 333 [27.1%] female and 324 522 [72.9%] male) were studied. Compared with male beneficiaries, female beneficiaries were more likely to have an unplanned admission (66 425 [55.2%] vs 157 895 [48.7%], P < .001) and receive care at low-quality (vs high-quality) hospitals (odds ratio, 1.26; 95% CI, 1.23-1.29; P < .001). Overall, risk-adjusted female mortality was 4.24% (95% CI, 4.20%-4.27%), and male mortality was 2.75% (95% CI, 2.75%-2.77%), with an absolute difference of 1.48 (95% CI, 1.45-1.51) percentage points (P < .001). At the highest-quality hospitals, male mortality was 1.57% (95% CI, 1.56%-1.59%), and female mortality was 2.58% (95% CI, 2.54%-2.62%), with an absolute difference of 1.01 (95% CI, 0.97-1.04) percentage points (P < .001). At the lowest-quality hospitals, male mortality was 4.94% (95% CI, 4.88%-5.01%), and female mortality was 7.02% (95% CI, 6.90%-7.13%), with an absolute difference of 2.07 (95% CI, 1.95-2.19) percentage points (P < .001). Female beneficiaries receiving care at low-quality hospitals had a higher mortality than male beneficiaries receiving care at the high-quality hospitals (7.02% vs 1.57%, P < .001).

Conclusions and Relevance

In this cohort study of Medicare beneficiaries undergoing coronary artery bypass grafting, female beneficiaries were more likely to receive care at low-quality hospitals, where the sex disparity in mortality was double that of high-quality hospitals. Quality improvement targeting low-quality hospitals as well as equitable referral of female beneficiaries to higher-quality hospitals may narrow the sex disparity after coronary artery bypass grafting.

The anti-gender threat: An ethical, democratic, and scientific imperative for NIH research/ers

Anti-gender campaigns in the United States and globally have promoted policies and legislation that significantly limit bodily autonomy for women, transgender, and nonbinary people. This attack on the human rights of women and gender-diverse communities not only reflects implicit and explicit bias but also detrimentally impacts population health and well-being. We outline the domestic and global rise of anti-gender campaigns and their deep historical connections to broader forms of discrimination and inequality to argue that there is an ethical, democratic, and scientific imperative to more critically center and contextualize gender in health research. While the inclusion of gender as a complex concept in research design, implementation, and dissemination is important, we emphasize that gender inequities must be understood as inextricable from other systems of discrimination and exclusion. To that end, this commentary outlines two actions: for researchers to advance critical approaches to gender as part of a broader landscape of discrimination, and for the US National Institutes of Health to integrate both sex and gender into funded research.

Emotional reactivity linking assaultive trauma and risky behavior: Evidence of differences between cisgender women and men

Accumulating evidence suggests that trauma exposure is positively associated with future engagement in risky behavior, such as substance misuse, aggression, risky sex, and self-harm. However, the psychological factors driving this association and their relevance across gender groups require further clarification. In a community sample of 375 adults with a high rate of trauma exposure (age range: 18-55 years, M = 32.98 years, SD = 10.64; 76.3% assaultive trauma exposure), we examined whether emotional reactivity linked lifetime assaultive trauma exposure with past-month risky behavior. We also explored whether this model differed for cisgender women (n = 178, 47.6%) and men (n = 197, 52.5%). As hypothesized, assaultive trauma was positively related to emotional reactivity, β = .20, SE = 0.03, t(369) = 3.65, p < .001, which, in turn, partially accounted for the association between assaultive trauma and past-month risky behavior, indirect effect: β = .03, SE = 0.01, 95% bootstrapped CI [0.01, 0.06]. Gender moderated this association such that assaultive trauma was indirectly associated with risky behavior via emotional reactivity for women but not for men, index moderation: B = -0.03, SE = 0.02, 95% bootstrapped CI [-0.07, -0.01]. Cross-sectional results suggest that emotional reactivity may be a proximal target for clinical intervention to aid in the reduction of risky behavior among women.

Meta Data Analysis of Sex Distribution of Study Samples Reported in Summer Biomechanics, Bioengineering, and Biotransport Annual Conference Abstracts

The biased use of male subjects in biomedical research has created limitations, underscoring the importance of including women to enhance the outcomes of evidence-based medicine and to promote human health. While federal policies (e.g., the 1993 Revitalization Act and the 2016 Sex as a Biological Variable Act) have aimed to improve sex balance in studies funded by the National Institutes of Health (NIH), data on sex inclusivity in non-NIH funded research remain limited. The objective of this study was to analyze the trend of sex inclusion in abstracts submitted to the Summer Biomechanics, Bioengineering, & Biotransport Conference (SB3C) over 7 years. We scored every abstract accepted to SB3C, and the findings revealed that approximately 20% of total abstracts included sex-related information, and this trend remained stable. Surprisingly, there was no significant increase in abstracts, including both sexes and those with balanced female and male samples. The proportion of abstracts with balanced sexes was notably lower than those including both sexes. Additionally, we examined whether the exclusion of one sex from the corresponding studies was justified by the research questions. Female-only studies had a 50% justification rate, while male-only studies had only 2% justification. Disparity in sex inclusion in SB3C abstracts was apparent, prompting us to encourage scientists to be more mindful of the sex of the research samples. Addressing sex inclusivity in biomechanics and mechanobiology research is essential for advancing medical knowledge and for promoting better healthcare outcomes for everyone.

Ensuring accountability for consideration of sex as a biological variable in research

The National Institute of Health (NIH) policy, Consideration of Sex as a Biological Variable (SABV) in NIH-funded Research (2015), focuses on the expectation that researchers account for the influence of SABV in vertebrate animal and human studies and provide a strong justification for single-sex investigations. When SABV is considered in the research design, data analyses, and reporting, the rigor and reproducibility of the research are elevated and inform best practices and precision health for all people. Additional recommendations include the appropriate use of terminology, integration into curricula, intersection with social determinants of health, and application of sex and gender equity guidelines when disseminating research. This paper is a "call to action" for nurse researchers to lean into and apply this policy's principles and our recommendations, from the bench to the bedside, to advance the equity and health of all people.

Osteochondroprogenitor cells and neutrophils expressing p21 and senescence markers modulate fracture repair

Cells expressing features of senescence, including upregulation of p21 and p16, appear transiently following tissue injury, yet the properties of these cells or how they contrast with age-induced senescent cells remains unclear. Here, we used skeletal injury as a model and identified the rapid appearance following fracture of p21+ cells expressing senescence markers, mainly as osteochondroprogenitors (OCHs) and neutrophils. Targeted genetic clearance of p21+ cells suppressed senescence-associated signatures within the fracture callus and accelerated fracture healing. By contrast, p21+ cell clearance did not alter bone loss due to aging; conversely, p16+ cell clearance, known to alleviate skeletal aging, did not affect fracture healing. Following fracture, p21+ neutrophils were enriched in signaling pathways known to induce paracrine stromal senescence, while p21+ OCHs were highly enriched in senescence-associated secretory phenotype factors known to impair bone formation. Further analysis revealed an injury-specific stem cell-like OCH subset that was p21+ and highly inflammatory, with a similar inflammatory mesenchymal population (fibro-adipogenic progenitors) evident following muscle injury. Thus, intercommunicating senescent-like neutrophils and mesenchymal progenitor cells were key regulators of tissue repair in bone and potentially across tissues. Moreover, our findings established contextual roles of p21+ versus p16+ senescent/senescent-like cells that may be leveraged for therapeutic opportunities.

Sex Matters-Insights from Testing Drug Efficacy in an Animal Model of Pancreatic Cancer

Preclinical studies rarely test the efficacy of therapies in both sexes. The field of oncology is no exception in this regard. In a model of syngeneic, orthotopic, metastasized pancreatic ductal adenocarcinoma we evaluated the impact of sex on pathological features of this disease as well as on the efficacy and possible adverse side effects of a novel, small molecule-based therapy inhibiting KRAS:SOS1, MEK1/2 and PI3K signaling in male and female C57BL/6J mice. Male mice had less tumor infiltration of CD8-positive cells, developed bigger tumors, had more lung metastasis and a lower probability of survival compared to female mice. These more severe pathological features in male animals were accompanied by higher distress at the end of the experiment. The evaluated inhibitors BI-3406, trametinib and BKM120 showed synergistic effects in vitro. This combinatorial therapy reduced tumor weight more efficiently in male animals, although the drug concentrations were similar in the tumors of both sexes. These results underline the importance of sex-specific preclinical research and at the same time provide a solid basis for future studies with the tested compounds.

The inclusion of the gender perspective in oncology research with Spanish participation

The gender perspective is important for a better diagnosis and treatment of diseases, especially in the field of oncology. This study aimed to analyse the gender approach in scientific articles in the field of oncology by studying the gender composition of the authorship of papers and the gender inclusion in the research carried out. A bibliographic search of articles and reviews signed by at least one Spanish institution published between 2010 and 2019 was carried out using the Science Citation Index Expanded database in the Oncology category. A total of 7523 studies were classified according to the gender composition determined by the author's name and a randomised sample was used to evaluate the inclusion of gender perspectives using a checklist. This study revealed a lack of gender parity in the authorship of oncology publications involving Spanish participation. Papers without author gender parity were eight times higher than papers with parity and showed a greater presence of male than female authorship (58 % versus 31 %). Regarding the introduction of the gender perspective, a negative response of 68 % referring to compliance with the entire checklist was obtained, and only a fifth of the articles presented gender balance in the study sample. Moreover, there is a positive correlation between gender parity in authorship and gender perspective integration in published research. In conclusion, there is a great need to advance the inclusion of gender perspectives in cancer research to overcome gender bias and promote better prevention, detection, and intervention for cancer.

A missed opportunity: A scoping review of the effect of sex and age on osteoarthritis using large animal models

OBJECTIVE

The objective was to critically analyze the published literature accounting for sex differences and skeletal age (open vs. closed physis) in preclinical animal models of OA, including the disaggregation of data by sex and skeletal maturity when data is generated from combined sex and/or multi-aged cohorts without proper confounding.

METHOD

A scoping literature review of PubMed, Web of Science, EMBASE, and SCOPUS was performed for studies evaluating the effect of sex and age in experimental studies and clinical trials utilizing preclinical large animal models of OA.

RESULTS

A total of 9727 papers were identified in large animal (dog, pig, sheep, goat, horse) models for preclinical OA research, of which 238 ex vivo and/or in vivo studies disclosed model type, animal species, sex, and skeletal age sufficient to analyze their effect on outcomes. Dogs, followed by pigs, sheep, and horses, were the most commonly used models. A paucity of preclinical studies evaluated the effect of sex and age in large animal models of naturally occurring or experimentally induced OA: 26 total studies reported some kind of analysis of the effects of sex or age, with 4 studies discussing the effects of sex only, 11 studies discussing the effects of age only, and 11 studies analyzing both the effects of age and sex.

CONCLUSION

Fundamental to translational research, OARSI is uniquely positioned to develop recommendations for conducting preclinical studies using large animal models of OA that consider biological mechanisms linked to sex chromosomes, skeletal age, castration, and gonadal hormones affecting OA pathophysiology and treatment response.

Sex Differences in Delirium after Coronary Artery Bypass Graft Surgery and Perioperative Neuropsychiatric Conditions: A Secondary Analysis of a Cohort Study

BACKGROUND

Biological sex influences the risk of depression and cognitive impairment, but its role in relation to postoperative delirium is unclear. This analysis investigates sex differences in delirium risk after coronary artery bypass graft (CABG) surgery and sex-related differences in relation to affective and cognitive symptoms.

METHODS

This is a secondary analysis of the Neuropsychiatric Outcomes After Heart Surgery (NOAHS) study, a single-site, observational study of a CABG surgery cohort (n = 149). Preoperative characteristics are stratified by sex, and baseline variables that differ by sex are evaluated to understand whether sex modifies their relationships with delirium. We also evaluate sex differences in one-month depression and cognition.

RESULTS

Female sex is associated with several delirium risk factors, including higher risk of preoperative depression and middle cerebral artery (MCA) stenosis. MCA stenosis was statistically associated with delirium only among women (OR 15.6, 95% CI 1.5, 164.4); mild cognitive impairment (MCI) was associated with delirium only in men (OR 4.6, 95% CI 1.2, 17.9). Other sex-based differences failed to reach statistical significance. Depression remained commoner among women 1 month post-CABG.

CONCLUSIONS

Women in this CABG cohort were more likely to have depression at baseline and 1 month postoperatively, as well as MCA stenosis and postoperative delirium. Sex might modify the relationship between post-CABG delirium and its risk factors including MCA stenosis and MCI. Cerebrovascular disease deserves study as a potential explanation linking female sex and a range of poor outcomes among women with coronary heart disease.

Vascular adaptation to exercise: a systematic review and audit of female representation

Biological sex is a salient factor in exercise-induced vascular adaptation. Although a male bias is apparent in the literature, the methodological quality of available studies in females is not yet known. This systematic review with narrative synthesis aimed to assess available evidence of exercise interventions on endothelial function, measured using flow-mediated dilation, in otherwise healthy individuals and athletes. A standardized audit framework was applied to quantify the representation of female participants. Using a tiered grading system, studies that met best-practice recommendations for conducting physiological research in females were identified. A total of 210 studies in 5,997 participants were included, with 18% classified as athletes. The primary exercise mode and duration were aerobic (49%) and acute (61%), respectively. Despite 53% of studies (n = 111) including at least one female, female participants accounted for only 39% of the total study population but 49% of the athlete population. Majority (49%) of studies in females were conducted in premenopausal participants. No studies in naturally menstruating, hormonal contraceptive-users or in participants experiencing menstrual irregularities met all best-practice recommendations. Very few studies (∼5%) achieved best-practice methodological guidelines for studying females and those that did were limited to menopause and pregnant cohorts. In addition to the underrepresentation of female participants in exercise-induced vascular adaptation research, there remains insufficient high-quality evidence with acceptable methodological control of ovarian hormones. To improve the overall methodological quality of evidence, adequate detail regarding menstrual status should be prioritized when including females in vascular and exercise research contexts.

Realism and robustness require increased sample size when studying both sexes

A recent article claimed that researchers need not increase the overall sample size for a study that includes both sexes. This Formal Comment points out that that study assumed two sexes to have the same variance, and explains why this is a unrealistic assumption.

Menstrual Phase Identification Questionnaire (MPIQ): Development and validation of a cross-sectional survey to identify follicular and luteal phases

Evidence continues to accumulate on the influence of the menstrual phase on several biobehavioral outcomes (e.g., substance misuse). Expansion of this knowledge is limited due to the burdensomeness of accurate menstrual phase assessment. Thus, we sought to create and validate a questionnaire that can be used as a stand-alone item within low-resource settings and numerous study designs (e.g., cross-sectional) to accurately identify both the follicular phase (FP) and the luteal phase (LP). Participants completed the self-administered four-item Menstrual Phase Identification Questionnaire (MPIQ) in two recently completed clinical trials. We assessed the accuracy of two MPIQ scoring criteria (less restrictive and more restrictive), as compared to self-report of onset of menses alone, with progesterone confirmation via dried blood spots. Participants (n = 59) were, on average, 33.7 (standard deviation [SD]: ± 4.3) years old and provided a total of 83 responses. Assessing FP and LP using the self-reported onset of menses alone classified 65.1% of the responses with an overall phase identification accuracy of 60.2%. While the more restrictive MPIQ scoring classified 100% of the responses, it yielded a similar accuracy (68.4%). In contrast, the less restrictive MPIQ scoring classified 100% of the responses and also significantly improved phase identification accuracy to 92.1% (p < .001). The MPIQ, as a stand-alone item, allows all cross-sectional responses to be classified with a high level of accuracy. This low-burden questionnaire can be used alone to identify FP and LP in studies that may be otherwise limited by study design, finances, and/or participant burden. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Representation of women in neuropsychology research prior to the COVID-19 pandemic

OBJECTIVE

Prior work has demonstrated that women have been historically underrepresented across various research fields, including neuropsychology. Given these disparities, the goal of this study was to systematically evaluate the inclusion of women as participants in neuropsychology research. The current study builds upon previous research by examining articles from eight peer-reviewed neuropsychology journals published in 2019.

METHOD

Empirical articles examining human samples were included in the current review if they were available in English. Eligible articles were examined to glean whether the main topic of the article was related to a gender issue, how gender was categorized, the gender distribution of the sample, whether gender was considered in analyses, whether gender was addressed in the discussion, and what age categories the study examined.

RESULTS

There was a relatively even distribution of men (51.76%) and women (48.24%) in neuropsychological research studies reviewed. There were twice as many studies that included only men compared to only women (16 vs. 8 studies), and nearly twice as many studies consisted of ≥ 75% men (16.6%) compared to ≥75% of women (8.5%). Gender-focused research was limited (3%). Furthermore, gender was frequently disregarded in analyses (58%) and often not addressed in the discussion (75%).

CONCLUSIONS

The current study highlights the limitations within neuropsychology related to the representation of women in research. Although it is encouraging that neuropsychological research is generally inclusive of women participants, future research should aim to more comprehensively investigate how gender may influence cognitive risk and resilience factors across different clinical presentations. Recommendations to begin addressing this challenge and to move toward more gender-equitable research are provided.

Investigating female versus male differences in white matter neuroplasticity associated with complex visuo-motor learning

Magnetic resonance imaging (MRI) has increasingly been used to characterize structure-function relationships during white matter neuroplasticity. Biological sex differences may be an important factor that affects patterns of neuroplasticity, and therefore impacts learning and rehabilitation. The current study examined a participant cohort before and after visuo-motor training to characterize sex differences in microstructural measures. The participants (N = 27) completed a 10-session (4 week) complex visuo-motor training task with their non-dominant hand. All participants significantly improved movement speed and their movement speed variability over the training period. White matter neuroplasticity in females and males was examined using fractional anisotropy (FA) and myelin water fraction (MWF) along the cortico-spinal tract (CST) and the corpus callosum (CC). FA values showed significant differences in the middle portion of the CST tract (nodes 38-51) across the training period. MWF showed a similar cluster in the inferior portion of the tract (nodes 18-29) but did not reach significance. Additionally, at baseline, males showed significantly higher levels of MWF measures in the middle body of the CC. Combining data from females and males would have resulted in reduced sensitivity, making it harder to detect differences in neuroplasticity. These findings offer initial insights into possible female versus male differences in white matter neuroplasticity during motor learning. This warrants investigations into specific patterns of white matter neuroplasticity for females versus males across the lifespan. Understanding biological sex-specific differences in white matter neuroplasticity may have significant implications for the interpretation of change associated with learning or rehabilitation.

Sex-specific variations in spatial reference memory acquisition: Insights from a comprehensive behavioral test battery in C57BL/6JRj mice

Sex differences in declarative memory are described in humans, revealing a female or a male advantage depending on the task. Specifically, spatial memory (i.e., spatial navigation) is typically most efficient in men. This sexual dimorphism has been replicated in male rats but not clearly in mice. In this study, sex differences in spatial memory were assessed in thirty-six C57BL/6 J mice (Janvier Labs; i.e., C57BL/6JRj mice), a widely used mouse substrain. Both male and female mice (12 weeks-old) were subjected to standard behavioral paradigms: the elevated plus maze, the open field test, the novel object and place tests, the forced swimming test, and the water maze test for spatial navigation. Across assessment, no sex differences were found in measures of locomotor activity, emotional and behavioral responses, and object and place recognition memories. In the water maze, male mice were faster in learning the platform location in the reference memory training and used more spatial strategies during the first training days. However, both sexes reached a similar asymptotic performance and performed similarly in the probe trial for long-term memory consolidation. No sex differences were found in the cued training, platform inversion sessions, or spatial working memory sessions. Hippocampal expression of the brain-derived neurotrophic factor was similar in both sexes, either in basal conditions or after performing the behavioral training battery. Importantly, female mice were not more variable than males in any measure analyzed. This outcome encourages the investigation of sex differences in animal models and the usefulness of including female mice in behavioral research.

Sex differences in colonic gene expression and fecal microbiota composition in a mouse model of obesity-associated colorectal cancer

This study investigated the sex-specific correlation between obesity and colorectal cancer emphasizing a more pronounced association in males. Estrogen, chromosomal genes, and gut bacteria were assessed in C57BL6/J male, female and ovariectomized (OVX) female mice, subjected to either a low-fat diet (LFD) or high-fat diet (HFD) for 14 weeks. Induction of colon tumor involved azoxymethane (10 mg/kg) administration, followed by three cycles of dextran sulfate sodium. Male mice on HFD exhibited higher final body weight and increased colon tumors compared to females. Colonic mucin 2 expression was significantly higher in females. HFD-modulated differentially expressed genes numbered 290 for males, 64 for females, and 137 for OVX females. Only one up-regulated gene (Gfra3) overlapped between females and OVX females, while two down-regulated genes (Thrsp and Gbp11) overlapped between males and OVX females. Genes up-regulated by HFD in males were linked to cytokine-cytokine interaction, HIF-1 signaling pathway, central carbon metabolism in cancer. Sex-specific changes in gut microbial composition in response to HFD were observed. These findings suggest a male-specific vulnerability to HFD-induced colon tumor formation, implicating key genes and colonic bacteria in colon tumorigenesis.

Effect of Mavacamten in Women Compared With Men With Obstructive Hypertrophic Cardiomyopathy: Insights From EXPLORER-HCM

BACKGROUND

Compared with men, women with hypertrophic cardiomyopathy (HCM) have a higher incidence of heart failure and worse outcomes. We investigated baseline clinical and echocardiographic characteristics and response to mavacamten among women compared with men in the EXPLORER-HCM study (Clinical Study to Evaluate Mavacamten [MYK-461] in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy).

METHODS

A prespecified post hoc analysis of sex from the blinded, randomized EXPLORER-HCM trial of mavacamten versus placebo in symptomatic patients with obstructive HCM was performed. Baseline characteristics were compared with t tests for continuous variables (expressed as mean values) and χ2 tests for categorical variables. Prespecified primary, secondary, and exploratory end points and echocardiographic measurements from baseline to end of treatment (week 30) were analyzed with ANCOVA for continuous end points and a generalized linear model with binomial distribution for binary end points, with adjustment for each outcome's baseline value, New York Heart Association class, β-blocker use, and ergometer type.

RESULTS

At baseline, women (n=102) were older (62 years versus 56 years; P<0.0001), had lower peak oxygen consumption (16.7 mL·kg-1·min-1 versus 21.3 mL·kg-1·min-1; P<0.0001), were more likely to be assigned New York Heart Association class III (42% versus 17%; P<0.0001), had worse health status (Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score 64 versus 75; P<0.0001), and had higher baseline plasma NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels (1704 ng/L versus 990 ng/L; P=0.004) than men (n=149). After 30 weeks of mavacamten treatment, similar improvements were observed in women and men in the primary composite end point (percentage difference on mavacamten versus placebo, 22% versus 19%, respectively; P=0.759) and in the secondary end points of change in postexercise left ventricular outflow tract gradient (-42.4 mm Hg versus -33.6 mm Hg; P=0.348), change in peak oxygen consumption (1.2 mL·kg-1·min-1 versus 1.6 mL·kg-1·min-1; P=0.633), and percentage achieving ≥1 New York Heart Association class improvement (41% versus 28%; P=0.254). However, women had greater improvement in health status (Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score 14.8 versus 6.1; P=0.026) and in the exploratory end point of NT-proBNP levels (-1322 ng/L versus -649 ng/L; P=0.0008).

CONCLUSIONS

Although at baseline women with symptomatic obstructive HCM enrolled in EXPLORER-HCM were older and had worse heart failure and health status than men, treatment with mavacamten resulted in similar improvements in the primary and most secondary EXPLORER-HCM end points and greater improvements in health status and NT-proBNP.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03470545.

Osteochondroprogenitor cells and neutrophils expressing p21 and senescence markers modulate fracture repair

Cells expressing features of senescence, including upregulation of p21 and p16, appear transiently following tissue injury, yet the properties of these cells or how they contrast with age-induced senescent cells remains unclear. Here, we used skeletal injury as a model and identified the rapid appearance following fracture of p21+ cells expressing senescence markers, mainly as osteochondroprogenitors (OCHs) and neutrophils. Targeted genetic clearance of p21+ cells suppressed senescence-associated signatures within the fracture callus and accelerated fracture healing. By contrast, p21+ cell clearance did not alter bone loss due to aging; conversely, p16+ cell clearance, known to alleviate skeletal aging, did not affect fracture healing. Following fracture, p21+ neutrophils were enriched in signaling pathways known to induce paracrine stromal senescence, while p21+ OCHs were highly enriched in senescence-associated secretory phenotype factors known to impair bone formation. Further analysis revealed an injury-specific stem cell-like OCH subset that was p21+ and highly inflammatory, with a similar inflammatory mesenchymal population (fibro-adipogenic progenitors) evident following muscle injury. Thus, intercommunicating senescent-like neutrophils and mesenchymal progenitor cells are key regulators of tissue repair in bone and potentially across tissues. Moreover, our findings establish contextual roles of p21+ vs p16+ senescent/senescent-like cells that may be leveraged for therapeutic opportunities.

Awareness of the impact of sex and gender in the disease risk and outcomes in hematology and medical oncology-a survey of Swiss clinicians

BACKGROUND

Although male and female cancer patients are distinct in many ways, there is a limited understanding in the differences between male and female biology and differing pharmacokinetic responses to cancer drugs. In fact, sex and gender are currently not considered in most treatment decisions in the fields of oncology and hematology. The lack of knowledge about potential sex differences in both disciplines may lead to differences in treatment efficacy, toxicity, and the overall survival (OS) of patients.

AIM

To evaluate their awareness about sex and gender in clinical practice we surveyed Swiss hematologists and oncologists from September to November 2022.

METHODS

We collected data about the clinical knowledge, experimental research, palliative care, quality of life, as well as the participant perception of the importance of sex and gender. We identified 767 eligible clinicians, of whom 150 completed the survey (20% response rate).

RESULTS

While most participants agreed that sex and gender were relevant when treating patients, it became clear that fewer participants knew about sex and gender differences in treatment toxicity and survival, which in turn would affect the treatment of their patients. Most participants agreed that this topic should be integrated into continuing education and research.

CONCLUSION

Our findings indicate the need for more awareness and training on sex and gender in cancer research and clinical care among oncologists and hematologists. Ideally, by better educating medical students and health professionals, a demand is created for improving research policies, publications and therefore patient care.

Comparison of nurse and resident physician paging frequency by sex in the emergency department

Objectives

The role of biological sex in interprofessional relationships is an important factor in collaborative health care settings such as the emergency department (ED) but one that has been sparsely studied. While there is anecdotal evidence on gender-based differences in communication, little research has focused on this topic. The goal of this study was to determine whether there are differences in paging frequency between nurses and male and female residents.

Methods

We conducted a retrospective review of patient visits to our urban, tertiary care academic ED between January 1 and April 1, 2021. Only pages from nurses to emergency medicine (EM) residents were included. Outcome variables included number of pages received by sex, number of unique ED visits, and mean number of pages per unique visit. Pearson's chi-square tests were used to analyze differences between observed and expected results.

Results

A total of 15,617 pages from nurses to residents over 6843 unique patient visits to the ED were analyzed. This included 187 nurses, 162 (87%) of whom were female and 25 (13%) were male. Of the 39 residents, 12 (31%) were female and 27 (69%) were male. Female residents received 4500 pages over 2228 unique patient ED visits, or a mean of two pages per patient with a mean of 186 unique ED visits per female resident. Male residents received 11,117 pages over 4615 unique patient ED visits, or a mean of 2.4 pages per patient, with a mean of 171 unique ED visits per male resident. This difference in pages per patient was statistically significant (χ2(1) = 369, p < 0.001).

Conclusions

We found that male residents received significantly more pages per patient than their female colleagues. Overall, further research is required to understand the factors, such as characteristics of patients or preferred communication methods of providers, that drive this disparity and what the implications are for patient outcomes.

Comprehensive evaluation of smoking exposures and their interactions on DNA methylation

BACKGROUND

Smoking impacts DNA methylation, but data are lacking on smoking-related differential methylation by sex or dietary intake, recent smoking cessation (<1 year), persistence of differential methylation from in utero smoking exposure, and effects of environmental tobacco smoke (ETS).

METHODS

We meta-analysed data from up to 15,014 adults across 5 cohorts with DNA methylation measured in blood using Illumina's EPIC array for current smoking (2560 exposed), quit < 1 year (500 exposed), in utero (286 exposed), and ETS exposure (676 exposed). We also evaluated the interaction of current smoking with sex or diet (fibre, folate, and vitamin C).

FINDINGS

Using false discovery rate (FDR < 0.05), 65,857 CpGs were differentially methylated in relation to current smoking, 4025 with recent quitting, 594 with in utero exposure, and 6 with ETS. Most current smoking CpGs attenuated within a year of quitting. CpGs related to in utero exposure in adults were enriched for those previously observed in newborns. Differential methylation by current smoking at 4-71 CpGs may be modified by sex or dietary intake. Nearly half (35-50%) of differentially methylated CpGs on the 450 K array were associated with blood gene expression. Current smoking and in utero smoking CpGs implicated 3049 and 1067 druggable targets, including chemotherapy drugs.

INTERPRETATION

Many smoking-related methylation sites were identified with Illumina's EPIC array. Most signals revert to levels observed in never smokers within a year of cessation. Many in utero smoking CpGs persist into adulthood. Smoking-related druggable targets may provide insights into cancer treatment response and shared mechanisms across smoking-related diseases.

FUNDING

Intramural Research Program of the National Institutes of Health, Norwegian Ministry of Health and Care Services and the Ministry of Education and Research, Chief Scientist Office of the Scottish Government Health Directorates and the Scottish Funding Council, Medical Research Council UK and the Wellcome Trust.

Assessing Dose- and Sex-Dependent Antinociceptive Effects of Cannabidiol and Amitriptyline, Alone and in Combination, and Exploring Mechanism of Action Involving Serotonin 1A Receptors

Inflammatory pain is caused by tissue hypersensitization and is a component of rheumatic diseases, frequently causing chronic pain. Current guidelines use a multimodal approach to pain and sociocultural changes have renewed interest in cannabinoid use, particularly cannabidiol (CBD), for pain. The tricyclic antidepressant amitriptyline (AT) is approved for use in pain-related syndromes, alone and within a multimodal approach. Therefore, we investigated sex- and dose-dependent effects of CBD and AT antinociception in the 2.5% formalin inflammatory pain model. Male and female C57BL/6J mice were pretreated with either vehicle, CBD (0.3-100 mg/kg), or AT (0.1-30 mg/kg) prior to formalin testing. In the acute phase, CBD induced antinociception after administration of 30-100 mg/kg in males and 100 mg/kg in females and in the inflammatory phase at doses of 2.5-100 mg/kg in males and 10-100 mg/kg in females. In the acute phase, AT induced antinociception at 10 mg/kg for all mice, and at 0.3 mg/kg in males and 3 mg/kg in female mice in the inflammatory phase. Combining the calculated median effective doses of CBD and AT produced additive effects for all mice in the acute phase and for males only in the inflammatory phase. Use of selective serotonin 1A receptor antagonist N-[2-[4-(2-methoxyphenyl)-1 piperazinyl]ethyl]-N-2-pyridinylcyclohexanecarboxamide (WAY-100635) maleate (0.1 mg/kg) before co-administration of CBD and AT reversed antinociception in the acute and partially reversed antinociception in the inflammatory phase. Administration of AT was found to enhance cannabinoid receptor type 1mRNA expression only in female mice. These results suggest a role for serotonin and sex in mediating cannabidiol and amitriptyline-induced antinociception in inflammatory pain. SIGNIFICANCE STATEMENT: Inflammatory pain is an important component of both acute and chronic pain. We have found that cannabidiol (CBD) and amitriptyline (AT) show dose-dependent, and that AT additionally shows sex-dependent, antinociceptive effects in an inflammatory pain model. Additionally, the combination of CBD and AT was found to have enhanced antinociceptive effects that is partially reliant of serotonin 1A receptors and supports the use of CBD within a multimodal approach to pain.

Early Post-Natal Immune Activation Leads to Object Memory Deficits in Female Tsc2+/- Mice: The Importance of Including Both Sexes in Neuroscience Research

There is evidence that viral infections during pre-natal development constitute a risk factor for neuropsychiatric disorders and lead to learning and memory deficits. However, little is known about why viral infections during early post-natal development have a different impact on learning and memory depending on the sex of the subject. We previously showed that early post-natal immune activation induces hippocampal-dependent social memory deficits in a male, but not in a female, mouse model of tuberous sclerosis complex (TSC; Tsc2+/- mice). Here, we explored the impact of a viral-like immune challenge in object memory. We demonstrate that early post-natal immune activation (during the first 2 weeks of life) leads to object memory deficits in female, but not male, mice that are heterozygous for a gene responsible for tuberous sclerosis complex (Tsc2+/- mice), while no effect was observed in wild type (WT) mice. Moreover, we found that the same immune activation in Tsc2+/- adult mice was not able to cause object memory deficits in females, which suggests that the early post-natal development stage constitutes a critical window for the effects of immune challenge on adult memory. Also, our results suggest that mTOR plays a critical role in the observed deficit in object memory in female Tsc2+/- mice. These results, together with previous results published by our laboratory, showing sex-specific memory deficits due to early post-natal immune activation, reinforce the necessity of using both males and females for research studies. This is especially true for studies related to immune activation, since the higher levels of estrogens in females are known to affect inflammation and to provide neuroprotection.

Long-read RNA sequencing identifies region- and sex-specific C57BL/6J mouse brain mRNA isoform expression and usage

Alternative splicing (AS) contributes to the biological heterogeneity between species, sexes, tissues, and cell types. Many diseases are either caused by alterations in AS or by alterations to AS. Therefore, measuring AS accurately and efficiently is critical for assessing molecular phenotypes, including those associated with disease. Long-read sequencing enables more accurate quantification of differentially spliced isoform expression than short-read sequencing approaches, and third-generation platforms facilitate high-throughput experiments. To assess differences in AS across the cerebellum, cortex, hippocampus, and striatum by sex, we generated and analyzed Oxford Nanopore Technologies (ONT) long-read RNA sequencing (lrRNA-Seq) C57BL/6J mouse brain cDNA libraries. From >85 million reads that passed quality control metrics, we calculated differential gene expression (DGE), differential transcript expression (DTE), and differential transcript usage (DTU) across brain regions and by sex. We found significant DGE, DTE, and DTU across brain regions and that the cerebellum had the most differences compared to the other three regions. Additionally, we found region-specific differential splicing between sexes, with the most sex differences in DTU in the cortex and no DTU in the hippocampus. We also report on two distinct patterns of sex DTU we observed, sex-divergent and sex-specific, that could potentially help explain sex differences in the prevalence and prognosis of various neurological and psychiatric disorders in future studies. Finally, we built a Shiny web application for researchers to explore the data further. Our study provides a resource for the community; it underscores the importance of AS in biological heterogeneity and the utility of long-read sequencing to better understand AS in the brain.

Gender as a social and structural variable: research perspectives from the National Institutes of Health (NIH)

Gender is a social and structural variable that encompasses multiple domains, each of which influences health: gender identity and expression, gender roles and norms, gendered power relations, and gender equality and equity. As such, gender has far-reaching impacts on health. Additional research is needed to continue delineating and untangling the effects of gender from the effects of sex and other biological variables. The National Institutes of Health (NIH) vision for women's health is a world in which the influence of sex and/or gender are integrated into the health research enterprise. However, much of the NIH-supported research on gender and health has, to date, been limited to a small number of conditions (e.g., HIV, mental health, pregnancy) and locations (e.g., sub-Saharan Africa; India). Opportunities exist to support transdisciplinary knowledge transfer and interdisciplinary knowledge building by advancing health-related social science research that incorporates best practices from disciplines that have well-established methods, theories, and frameworks for examining the health impacts of gender and other social, cultural, and structural variables.

Anticoagulation use is associated with lower fetal fraction and more indeterminate results

BACKGROUND

Maternal anticoagulation use may increase indeterminate result rates on cell-free DNA-based screening, but existing studies are confounded by inclusion of individuals with autoimmune disease, which alone is associated with indeterminate results. Changes in chromosome level Z-scores are proposed by others as a reason for indeterminate results, but the etiology of this is uncertain.

OBJECTIVE

This study aimed to evaluate differences in fetal fraction, indeterminate result rate, and total cell-free DNA concentration in individuals on anticoagulation without autoimmune disease compared with controls undergoing noninvasive prenatal screening. Secondly, using a nested case-control design, we evaluated differences in fragment size, GC-content, and Z-scores to evaluate laboratory-level test characteristics.

STUDY DESIGN

This was a retrospective single-institution study of pregnant individuals undergoing cell-free DNA-based noninvasive prenatal screening using low-pass whole-genome sequencing between 2017 and 2021. Individuals with autoimmune disease, suspected aneuploidy, and cases where fetal fraction was not reported were excluded. Anticoagulation included heparin-derived products (unfractionated heparin, low-molecular-weight heparin), clopidogrel, and fondaparinux, with a separate group for those on aspirin alone. An indeterminate result was defined as fetal fraction <4%. We evaluated the association between maternal anticoagulation or aspirin use, and fetal fraction, indeterminate results, and total cell-free DNA concentration using univariate and multivariate analyses, controlling for body mass index, gestational age at sample collection, and fetal sex. For the anticoagulation cohort, we compared laboratory-level test characteristics among cases (on anticoagulation) and a subset of controls. Lastly, we evaluated for differences in chromosome level Z-scores among those on anticoagulation with and without indeterminate results.

RESULTS

A total of 1707 pregnant individuals met the inclusion criteria. Of those, 29 were on anticoagulation and 81 were on aspirin alone. For those on anticoagulation, the fetal fraction was significantly lower (9.3% vs 11.7%; P<.01), the indeterminate result rate was significantly higher (17.2% vs 2.7%; P<.001), and the total cell-free DNA concentration was significantly higher (218 pg/μL vs 83.7 pg/μL; P<.001). Among those on aspirin alone, the fetal fraction was lower (10.6% vs 11.8%; P=.04); however, there were no differences in the rate of indeterminate results (3.7% vs 2.7%; P=.57) or total cell-free DNA concentration (90.1 pg/μL vs 83.8 pg/μL; P=.31). After controlling for maternal body mass index, gestational age at sample collection, and fetal sex, anticoagulation was associated with an >8-fold increase in the likelihood of an indeterminate result (adjusted odds ratio, 8.7; 95% confidence interval, 3.1-24.9; P<.001), but not aspirin (adjusted odds ratio, 1.2; 95% confidence interval, 0.3-4.1; P=.8). Anticoagulation was not associated with appreciable differences in cell-free DNA fragment size or GC-content. Although differences in chromosome 13 Z-scores were observed, none were observed for chromosomes 18 or 21, and this difference did not contribute to the indeterminate result call.

CONCLUSION

In the absence of autoimmune disease, anticoagulation use, but not aspirin, is associated with lower fetal fraction, higher total cell-free DNA concentration, and higher rates of indeterminate results. Anticoagulation use was not accompanied by differences in cell-free DNA fragment size or GC-content. Statistical differences in chromosome level Z-scores did not clinically affect aneuploidy detection. This suggests a likely dilutional effect by anticoagulation on cell-free DNA-based noninvasive prenatal screening assays contributing to low fetal fraction and indeterminate results, and not laboratory or sequencing-level changes.

Exploring the ex vivo effects of Naja mossambica venom on the ultrastructure and viscoelastic properties of human blood

Background

Venomous snake bites have been listed as a neglected tropical disease by the World Health Organization. The Mozambique spitting cobra (Naja mossambica) is found in Sub-Saharan African countries, and its venom has been identified to predominantly result in cytotoxic effects. However, there is limited evidence on the possible hemotoxic effects of this venom on human blood.

Objectives

In this cross-sectional study, we investigated how Mozambique spitting cobra venom affects blood clot formation.

Methods

Cell morphology and clot architecture were studied by using microscopy techniques. We also studied the effects of the venom on platelets by measuring platelet activity with the global thrombosis test, followed by analyzing the viscoelasticity with thromboelastography using a 0.025 ng/μL venom concentration.

Results

The most prominent findings indicated that the viscoelastic profile in the venom-treated blood samples formed an unstable and elastic clot. The clot architecture seen with the scanning electron microscopy analysis showed an altered fibrin network and red blood cells, confirmed by the increased axial ratios, and aggregated platelets with spreading.

Conclusion

These findings may offer insights into the species-specific effects of snake venom on human blood and add value to the clinical workup in confirming envenomation. Further research is needed to correlate the 20 minute whole blood clotting test with measurable values from the thromboelastography within the context of snake envenomation. This may offer a bridge between cost, early diagnosis, and treatment of snake envenomation in resource-constrained countries.

Plasmodium knowlesi in pig-tailed macaques: a potential new model for malaria vaccine research

BACKGROUND

Plasmodium knowlesi is an established experimental model for basic and pre-clinical malaria vaccine research. Historically, rhesus macaques have been the most common host for malaria vaccine studies with P. knowlesi parasites. However, rhesus are not natural hosts for P. knowlesi, and there is interest in identifying alternative hosts for vaccine research. The study team previously reported that pig-tailed macaques (PTM), a natural host for P. knowlesi, could be challenged with cryopreserved P. knowlesi sporozoites (PkSPZ), with time to blood stage infection equivalent to in rhesus. Here, additional exploratory studies were performed to evaluate PTM as potential hosts for malaria vaccine studies. The aim was to further characterize the parasitological and veterinary health outcomes after PkSPZ challenge in this macaque species.

METHODS

Malaria-naïve PTM were intravenously challenged with 2.5 × 103 PkSPZ and monitored for blood stage infection by Plasmodium 18S rRNA RT-PCR and thin blood smears. Disease signs were evaluated by daily observations, complete blood counts, serum chemistry tests, and veterinary examinations. After anti-malarial drug treatment, a subset of animals was re-challenged and monitored as above. Whole blood gene expression analysis was performed on selected animals to assess host response to infection.

RESULTS

In naïve animals, the kinetics of P. knowlesi blood stage replication was reproducible, with parasite burden rising linearly during an initial acute phase of infection from 6 to 11 days post-challenge, before plateauing and transitioning into a chronic low-grade infection. After re-challenge, infections were again reproducible, but with lower blood stage parasite densities. Clinical signs of disease were absent or mild and anti-malarial treatment was not needed until the pre-defined study day. Whole blood gene expression analysis identified immunological changes associated with acute and chronic phases of infection, and further differences between initial challenge versus re-challenge.

CONCLUSIONS

The ability to challenge PTM with PkSPZ and achieve reliable blood stage infections indicate this model has significant potential for malaria vaccine studies. Blood stage P. knowlesi infection in PTM is characterized by low parasite burdens and a benign disease course, in contrast with the virulent P. knowlesi disease course commonly reported in rhesus macaques. These findings identify new opportunities for malaria vaccine research using this natural host-parasite combination.

Female aging: when translational models don't translate

For many pathologies associated with aging, female patients present with higher morbidity and more frequent adverse events from treatments compared to male patients. While preclinical models are the foundation of our mechanistic understanding of age-related diseases, the most common models fail to recapitulate archetypical female aging trajectories. For example, while over 70% of the top age-related diseases are influenced by the systemic effects of reproductive senescence, we found that preclinical studies that include menopausal phenotypes modeling those seen in humans make up <1% of published aging biology research. The long-term impacts of pregnancy, birthing and breastfeeding are also typically omitted from preclinical work. In this Perspective, we summarize limitations in the most commonly used aging models, and we provide recommendations for better incorporating menopause, pregnancy and other considerations of sex in vivo and in vitro. Lastly, we outline action items for aging biology researchers, journals, funding agencies and animal providers to address this gap.

The Biological Basis of Sex Differences in Athletic Performance: Consensus Statement for the American College of Sports Medicine

ABSTRACT

Biological sex is a primary determinant of athletic performance because of fundamental sex differences in anatomy and physiology dictated by sex chromosomes and sex hormones. Adult men are typically stronger, more powerful, and faster than women of similar age and training status. Thus, for athletic events and sports relying on endurance, muscle strength, speed, and power, males typically outperform females by 10%-30% depending on the requirements of the event. These sex differences in performance emerge with the onset of puberty and coincide with the increase in endogenous sex steroid hormones, in particular testosterone in males, which increases 30-fold by adulthood, but remains low in females. The primary goal of this consensus statement is to provide the latest scientific knowledge and mechanisms for the sex differences in athletic performance. This review highlights the differences in anatomy and physiology between males and females that are primary determinants of the sex differences in athletic performance and in response to exercise training, and the role of sex steroid hormones (particularly testosterone and estradiol). We also identify historical and nonphysiological factors that influence the sex differences in performance. Finally, we identify gaps in the knowledge of sex differences in athletic performance and the underlying mechanisms, providing substantial opportunities for high-impact studies. A major step toward closing the knowledge gap is to include more and equitable numbers of women to that of men in mechanistic studies that determine any of the sex differences in response to an acute bout of exercise, exercise training, and athletic performance.

A nonparametric test of group distributional differences for hierarchically clustered functional data

Biological sex and gender are critical variables in biomedical research, but are complicated by the presence of sex-specific natural hormone cycles, such as the estrous cycle in female rodents, typically divided into phases. A common feature of these cycles are fluctuating hormone levels that induce sex differences in many behaviors controlled by the electrophysiology of neurons, such as neuronal membrane potential in response to electrical stimulus, typically summarized using a priori defined metrics. In this paper, we propose a method to test for differences in the electrophysiological properties across estrous cycle phase without first defining a metric of interest. We do this by modeling membrane potential data in the frequency domain as realizations of a bivariate process, also depending on the electrical stimulus, by adopting existing methods for longitudinal functional data. We are then able to extract the main features of the bivariate signals through a set of basis function coefficients. We use these coefficients for testing, adapting methods for multivariate data to account for an induced hierarchical structure that is a product of the experimental design. We illustrate the performance of the proposed approach in simulations and then apply the method to experimental data.

Rat models of diet-induced obesity and metabolic dysregulation: Current trends, shortcomings and considerations for future research

Rat diet-induced obesity and metabolic dysregulation (DIO/DIMD) is widely used as a pre-clinical model for human obesity and for testing weight-loss interventions. The aim of this review was to utilise a systematic literature survey of rat DIO/DIMD studies as a tool to document trends around study design and metabolic outcomes of these studies, and to consider ways in which the design of these studies may be improved to enhance the relevance thereof for human obesity research. In total, 110 comparisons between control and obesogenic dietary groups were included in the survey. Young male rats were found to be the model of choice, but fewer than 50% of studies provided comprehensive information about diet composition and energy intake. In addition, it was found that the majority of expected DIO/DIMD responses (hyperglycemia, hyperinsulinemia, dyslipidemia, hypoadiponectinemia) occurred at < 80% frequency, drawing into question the concept of a "typical" or "appropriate" response. We discuss the impact of differences in diet composition and energy intake on metabolic outcomes against the context of large heterogeneity of obesogenic diets employed in rat DIO/DIMD studies, and provide recommendations for the improvement of reporting standards around diet composition and dietary intake. In addition, we highlight the lack of data from female and older rats and describe considerations around the inclusion of sex and age as a variable in rat DIO/DIMD studies, aiming towards improving the applicability of these studies as a model of human obesity, which is most prevalent in women and older individuals.

The possible "calming effect" of subchronic supplementation of a standardised phospholipid carrier-based Melissa officinalis L. extract in healthy adults with emotional distress and poor sleep conditions: results from a prospective, randomised, double-blinded, placebo-controlled clinical trial

Background: Emotional distress conditions such as depression, anxiety, stress, and poor sleep are widespread health problems that have a significant impact on people's lives. Conventional drugs are commonly prescribed to treat emotional distress and poor sleep conditions; however, these medications have several limitations and have shown multiple side effects. Over recent years botanicals-based pharmacological agents have gained increasing research and clinical interest in the management of emotional distress and sleep disorder. Of note, Melissa officinalis L. (MO) leaf extract has demonstrated considerable neuropharmacological properties both in animal and human studies and has emerged as a promising natural "calming agent." However, research in this area is limited, and more studies are needed to validate its efficacy in amelioration of emotional distress and poor sleep conditions. Objectives: We aimed to assess the pharmacological effects of subchronic supplementation of an innovative standardised phospholipid carrier-based MO aqueous extract on emotional distress and poor sleep conditions. Design: A 3-week prospective, randomised, placebo-controlled, parallel-group, double-blinded clinical trial was conducted in 100 healthy adults complaining of a moderate degree of depression, anxiety, or stress, with scores of ≥14, ≥10, and ≥19, respectively, in the self-report Depression, Anxiety, and Stress Scale (DASS-42) or poor sleep, as indicated by the score of >5 in the Pittsburgh Sleep Quality Index (PSQI) scale. In addition, the impact of emotional distress and/or poor sleep on participants' mental wellbeing, emotional feelings, and quality of life was also assessed using the self-reported Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS), Positive and Negative Affect Schedule (PANAS) scale, and quality of life (WHO-QoL-BREF) scale, respectively. Results: Oral supplementation of 200 mg of phospholipid-based MO aqueous extract (Relissa™) tablets twice a day (i.e., 400 mg/day) for 3 weeks led to significant improvements in the depressive mood, anxiety, stress, positive and negative affect (emotional feelings), overall mental wellbeing, and quality-of-life scores (all p values <0.001). Supplementation of MO extract was well tolerated, and no treatment-emergent effects or serious adverse events were reported. Conclusion: According to the results of this study, the phospholipid carrier-based MO aqueous extract possesses considerable neuropharmacological properties, and its supplementation may provide a promising therapeutic option for the management of moderate emotional distress and/or poor sleep conditions. Clinical Trial Registration: clinicaltrials.gov, identifier NCT05602688.