Sex differences in the hypothalamic-pituitary-adrenal axis' response to stress: an important role for gonadal hormones

Repeated footshock stress enhances cocaine self-administration in male and female rats: Role of the cannabinoid receptor 1

Stress is a significant contributor to the development and progression of substance use disorders (SUDs) and is problematic as it is unavoidable in daily life. Therefore, it is important to understand the neurobiological mechanisms that underlie the influence of stress on drug use. We have previously developed a model of rat self-administration that employs an electric footshock stressor at the time of cocaine self-administration, resulting in an enhancement of cocaine self-administration. This stress enhancement of cocaine intake involves neurobiological mediators of stress and reward such as cannabinoid signaling. However, all of this work has been conducted in male rats. Here we test the hypothesis that repeated daily stress enhances cocaine self-administration in male and female rats. We further hypothesize that cannabinoid receptor 1 (CB1R) signaling is recruited by repeated stress to influence cocaine self-administration in both male and female rats. Male and female Sprague-Dawley rats self-administered cocaine (0.5 mg/kg/inf, i.v.) during a modified short-access paradigm wherein the 2 hr access was separated into four 30 min self-administration blocks separated by four 5 min drug free periods. Footshock stress significantly increased cocaine self-administration similarly in both male and female rats. Females displayed greater stress-enhanced time-out, non-reinforced responding, and stress-specific "front-loading" behavior. In males, systemic administration of a CB1R inverse agonist/antagonist Rimonabant only attenuated cocaine intake in rats with a history of combined repeated stress and cocaine self-administration. However, in females, Rimonabant attenuated cocaine self-administration in the no stress control group but only at the highest dose of Rimonabant (3 mg/kg, i.p.) suggesting that females show a greater sensitivity to CB1R antagonism. However, female rats with a history of stress showed even greater sensitivity to CB1R antagonism as both doses of Rimonabant (1, 3 mg/kg) attenuated cocaine self-administration in stress-enhanced rats, similar to males. Altogether these data demonstrate that stress can produce significant changes in cocaine self-administration and suggests that repeated stress at the time of cocaine self-administration recruits CB1Rs to regulate cocaine-taking behavior across sexes.

Maternal immune activation alters the GABAergic system in the prefrontal cortex of female rat offspring: Role of interleukin-6

Maternal immune activation (MIA) induces long-term cognitive impairments by modulating the gamma-aminobutyric acid (GABA)ergic system. Experimental evidence suggests that maternal immune challenge with bacterial active ingredient lipopolysaccharide (LPS) reduces GABAergic tone in the offspring's prefrontal cortex. In this study, we aimed to assess whether interleukin-6 (IL-6) contributes to this reduced GABAergic system in the prefrontal cortex of juvenile offspring. Pregnant rats were given intraperitoneal injections of either LPS (100 µg/Kg) or a pyrogen-free saline solution in the absence or the presence of an IL-6 neutralizing antibody (IL-6Ab, 10 µg/Kg) on gestation day (GD) 15, GD17 and GD19. Parvalbumin and somatostatin GABAergic interneurons and the density of inhibitory synapses were monitored in 30-day-old male and female rat offspring using fluorescent immunohistochemistry. The expression levels of Cl- transporters (NKCC1 and KCC2) were assessed using western blotting. Prenatal LPS induced a significant reduction in the cell density of parvalbumin-containing interneurons in the prefrontal cortex of female but not male rat offspring. LPS-induced MIA led to a reduction in the expression levels of NKCC1 in the prefrontal cortices of both male and female offspring. These long-lasting impacts of the MIA were alleviated when the IL-6Ab was co-administered with LPS during pregnancy. This study shows that the GABAergic system in the prefrontal cortex of female rats is highly sensitive to prenatal immune challenges. These data pave the way for exploring the specific mechanism(s) underlying the sex-dependent effects of early-life immune challenges.

Sex-specific differences in peripheral blood metabolites and biological functions in major depressive disorder: A systematic review and meta-analysis

To explore the sex-specific peripheral blood metabolites and biological functions altered in patients with major depressive disorder (MDD). A search was conducted on PubMed, Cochrane, Embase, Web of Science, and other databases published up to 11/2023. To maximize the search, we also reviewed systematic reviews and meta-analyses on the same topic. We included studies that conducted metabolic characterizations during current depressive episodes or after antidepressant treatments, with all data stratified by sex. Fifty-eight studies involving 83 cohorts with 5285 MDD participants were included in this meta-analysis. Random effects meta-analysis was conducted for data from ≥3 cohorts. We identified 5 sex-specific metabolites from 22 candidate peripheral blood metabolites. In males with MDD, we observed lower levels of estradiol and progesterone, alongside higher levels of androstenedione, dihydrotestosterone, and uric acid compared with female MDD patients. In addition, steroid hormone biosynthesis has been identified as a potentially sex-specific pathway. Our findings highlight significant evidence for targeting sex hormones as a broad understanding of MDD, providing potentially objective diagnostic and therapeutic insights.

Social isolation induces sexually aggressive behaviour in male Wistar rats

BACKGROUND

Sexual violence, a pervasive global issue, significantly impacts individuals and societies, necessitating a deeper understanding of its underlying biological mechanisms. This study aimed to elucidate the role of stress-induced dysregulation of the hypothalamus-pituitary-adrenocortical axis in sexual aggression in male Wistar rats. Employing a sexual aggression paradigm, we investigated the effects of social isolation on aggression, anxiety-like behaviour, and neurochemistry in virgin adult male Wistar rats.

RESULTS

The results showed that social isolation significantly escalated aggressive behaviours and induced anxiety-like responses in male rats. The sexual aggression test revealed that socially isolated males exhibited heightened aggression towards non-receptive females. Neurochemical analyses indicated significant alterations in key markers, such as corticotrophin-releasing hormone, oxytocin, and arginine vasopressin, correlating with the observed behavioural changes. Gene expression analyses revealed significant findings, particularly in the expression of the oxytocin receptor (OXTR) and vasopressin receptor 1 A (AVPR1A) genes. Social isolation and the duration of aggressive behaviour prior to the sexual aggression test significantly influenced OXTR expression in the hippocampus and AVPR1A expression in both the prefrontal cortex and hippocampus, highlighting the complex interplay between environmental stressors, neurochemical responses, and gene expression in the manifestation of sexual aggression behaviour.

CONCLUSIONS

This study underscores the critical impact of stress and social isolation on sexual aggression, providing valuable insights into possible neurobiological underpinnings of sexual violence. Understanding these mechanisms is crucial for developing effective interventions to mitigate the consequences of sexual aggression.

Sex-differences in brain multimodal estimates of white matter microstructure during early adolescence: Sex-specific associations with biological factors

Adolescence is marked by significant maturation of brain white matter microstructure, with evidence for sex-specific maturational trajectory. Most studies have examined conventional diffusion tensor imaging (DTI) metrics, which lack specificity to the underlying tissue modifications. In this study, we characterized sex-differences in white matter microstructure cross-sectionally using DTI, advanced diffusion spectrum imaging (DSI) and diffusion kurtosis imaging (DKI), as well as the white matter tract integrity-Watson (WMTI-W) biophysical model. We also aimed to explore the effect of age and biological systems undergoing sex-specific changes during adolescence, namely pubertal hormones, hypothalamic-pituitary-adrenal (HPA)-axis function, and glutathione-redox cycle homeostasis. The results indicate widespread sex-differences in all the white matter derived metrics, suggesting more advanced maturation in females compared to males as well as distinct tissue modifications underlying white matter maturation between males and females during this narrow developmental period. Additionally, the three biological factors explored appeared to be associated with indices of white matter maturation in females specifically, emphasizing this period as critical in female white matter development and sensitivity to environmental factors.

Sex- and trimester-specific impact of gestational co-exposure to organophosphate esters and phthalates on insulin action among preschoolers: Findings from the Ma'anshan birth cohort

INTRODUCTION

Prenatal exposure to organophosphate esters (OPEs) and phthalic acid esters (PAEs) is ubiquitous among pregnant individuals. However, research exploring the relationship between prenatal co-exposure to OPEs and PAEs and childhood insulin function remains limited.

METHODS

In this study, utilizing data from 2,246 maternal-fetal dyads in the Ma'anshan Birth Cohort, associations between co-exposure to OPEs and PAEs and insulin action were analyzed. Repeated measures of tris (2-chloroethyl) phosphate, six OPE metabolites, and seven PAE metabolites were collected from maternal urine. Homeostasis model assessment of insulin resistance (HOMA-IR) and the insulin action index (IAI) served as outcome measures. After adjusting for potential confounders, the effects of repeated exposure on insulin action were evaluated using generalized estimating equations, while mixture effects were assessed through BayesianKernel Machine Regression and Quantile-Based G-Computation.

RESULTS

The average age of the children at the time of the study was 5.33 years. Repeated measures analysis revealed that prenatal exposure to MEP was positively associated with increased HOMA-IR (β, 0.027; 95 % CI: 0.002, 0.053), while IAI was inversely correlated with rising MEP levels (β, 0.025; 95 % CI: -0.046, -0.004) and MEHHP exposure (β, -0.128; 95 % CI: -0.218, -0.037). Mixed exposure modeling further indicated that co-exposure to OPEs and PAEs was positively linked to HOMA-IR (β, 0.058; 95 % CI: 0.001, 0.114) and negatively correlated with IAI (β, -0.054; 95 % CI: -0.097, -0.010), with stronger effects observed during the second trimester. Notably, the association was more pronounced in female children compared to males.

CONCLUSIONS

This study provides the first epidemiological evidence highlighting the pregnancy- and sex-specific links between prenatal co-exposure to OPEs and PAEs and childhood insulin action.

The Long-Term Effects of Chronic Unpredictable Mild Stress Experienced During Adolescence Could Vary Depending on Biological Sex

Sex differences in the neurobiology of responses to chronic stress have been widely discussed but remain poorly understood. We found that chronic unpredictable mild stress (CUMS) experienced during adolescence induced different behavioral patterns in adult males and females. Immunohistochemical analysis of the CA1 field of the dorsal and ventral hippocampus revealed no quantitative or morphological changes in astrocytes in the long term after CUMS. Real-time PCR analysis showed no increase in the expression level of SigmaR1 after CUMS relative to individual housekeeping genes. Analysis of mouse cerebral cortex homogenates showed that IL-1β levels only decreased after CUMS in males. However, the SigmaR1 levels were significantly higher in the CUMS groups than in the control groups in both sexes. It can be concluded that biological sex and age influence the response to CUMS, although not in all cases. Further studies are needed to understand the effects of chronic stress on males and females. This is important because men and women have different risks for stress and mental disorders.

Prenatal Constant Light Exposure Induces Behavioral Deficits in Male and Female Rat Offspring: Effects of Prenatal Melatonin Treatment

Prenatal constant light exposure (CLE) impaired the anxiety response and circadian rhythms of testicular enzymes in adult male rat offspring, while melatonin corrected these deficiencies. However, the mechanism by which CLE induces these long-term behavioral consequences and the impact of melatonin system have not been examined. The aim of the present study was to investigate the effects of prenatal CLE and melatonin treatment on anxiety- and depression-like behaviors, and the melatonin system in male and female adult rat offspring. Six groups of male and female rat offspring (P60) exposed to either light/dark (LD) or CL regimes, and treated with vehicle or melatonin (10 mg/kg, s.c.) were evaluated for anxiety by open field (OF), elevated plus maze (EPM), and light/dark (LD) tests, and depressive-like response by splash test and sucrose preference test. Plasma adrenocorticotropic hormone (ACTH), corticosterone (CORT) and melatonin expression, and hippocampal MT1A and MT1b receptor expression were assessed by ELISA. Prenatal CLE induced behavioral deficits and elevated plasma CORT levels, while melatonin levels, their circadian rhythmicity, and hippocampal MT receptor expression were not altered in male and female offspring in the CLE regime. However, prenatal melatonin treatment corrected behavioral deficits in a sex-specific manner by up-regulating hippocampal MT receptors, even without altering systemic melatonin levels or normalizing CORT in either sex. The results of this study suggest critical insights into how prenatal environmental factors and therapeutic interventions shape physiological and behavioral outcomes.

The impact of adverse childhood experiences on adult physical, mental health, and abuse behaviors: A sex-stratified nationwide latent class analysis in Japan

Adverse childhood experiences (ACEs) have been reported to detrimentally impact physical and mental health. While experiencing multiple ACEs is common, previous research primarily assessed ACEs by their total count, neglecting the impacts of different experience types. Furthermore, sex-based differences in ACEs and their influences remain unclear. This study employed Latent Class Analysis (LCA) to uncover patterns of ACEs with consideration for sex differences, aiming to elucidate their effects on adult physical and mental health. A geographically nationally representative dataset from the "Japan COVID-19 and Society Internet Study (JACSIS)" conducted in 2022 was used. 13,715 men and 14,327 women retrospectively reported their experiences across fifteen ACEs. The analysis revealed four distinct ACE patterns for both sexes: a Multiple Adversities class with a wide range of severe ACEs, a Psychological Abuse class experiencing emotional abuse at home and bullying at school, a Poverty class facing economic hardships, and a Low Adversities class with the fewest ACEs. Multinomial logistic regression analysis indicated that more severe patterns of exposure correlated with heightened adverse adult outcomes. However, the extent of these impacts varied by sex and ACE pattern. For instance, men in Multiple Adversities and Psychological Abuse classes exhibited higher tendencies towards conducting physical and psychological abuse behaviors. While ACEs in men were linked to both underweight (in cases of psychological abuse) and obesity (across all classes), women with ACEs generally leaned towards higher body weight. These findings highlight the importance of developing support strategies sensitive to sex differences and the specific content of ACEs.

Sex-related hypothalamic-pituitary-gonadal and hypothalamic-pituitary-adrenal axis adaptation during military training

Reproductive endocrine function adapts to psychological, environmental, and energy-associated stressors. Multistressor environments upregulate hypothalamic-pituitary-adrenal (HPA) axis, causing suppression of the hypothalamic-pituitary-gonadal (HPG) axis, but it is not known if this pattern or its magnitude is sex biased. We compared HPG and HPA axis activity in 9 men and 34 women undergoing Army training. One-hour low-dose gonadorelin and Synacthen tests were conducted at 1 and 29 wk, measuring gonadotrophins and cortisol. Cortisol was measured from hair every 3 mo. Morning and evening salivary cortisol and psychometric questionnaires were measured at six timepoints. Sexes were compared over time by two-way ANOVA. Gonadotrophin responses were significantly higher in women than men in week 1, but no sex difference was seen at week 29 (no significant sex × time interaction). Week 1 cortisol response was higher among men, but week 29 cortisol response was higher among women (sex × time F(1,44) = 18.0, P < 0.001). Hair cortisol was higher among women than men beforehand, not different between sexes during the first 3 mo, and significantly higher among women during training months 5-11 (F(3,15) = 3.25, P = 0.024). Morning salivary cortisol was higher among women in weeks 8 and 14, but higher among men in week 29 (F(4,76) = 4.0, P = 0.005). No differences were seen in evening salivary cortisol. Psychometrics did not change or differ between sexes. HPA axis responses to military training were greater among women than men. HPG axis responses suggest greater downregulation among women. These findings will enable equitable and individualized management of people undergoing periods of intensive physical stress.NEW & NOTEWORTHY We conducted a comprehensive comparison of adrenal and reproductive function in men and women undergoing 11-mo military training. We found progressively elevated cortisol levels and dynamic cortisol response to stress among women, but not men, and suppression of reproductive function among women. The physiological impact of stressful military training was greater among women than men; this could not be explained by energy balance, and sex-specific effects of sleep, socio-ethnographic, or other stressors may be responsible.

Chronic unpredictable stress induces anxiety-like behavior and oxidative stress, leading to diminished ovarian reserve

Chronic stress can adversely affect the female reproductive endocrine system, potentially leading to disorders and impairments in ovarian function. However, current research lacks comprehensive understanding regarding the biochemical characteristics and underlying mechanisms of ovarian damage induced by chronic stress. We established a stable chronic unpredictable stress (CUS)-induced diminished ovarian reserve (DOR) animal model. Our findings demonstrated that prolonged CUS treatment over eight weeks resulted in increased atresia follicles in female mice. This atresia was accompanied by decreased AMH and increased FSH levels. Furthermore, we observed elevated levels of corticosterone both in the peripheral blood and within the ovary. Additionally, we detected abnormalities in ATP metabolism within the ovarian tissue. CUS exposure led to oxidative stress in the ovaries, fostering a microenvironment characterized by oxidative damage to mouse ovarian granulosa cells (mGCs) and heightened levels of reactive oxygen species. Furthermore, CUS prompted mGCs to undergo apoptosis via the mitochondrial pathway. These findings indicate a direct association between the fundamental physiological alterations leading to DOR and the oxidative phosphorylation processes within mGCs. The diminished ATP production by mGCs, triggered by CUS, emerges as a pivotal indicator of CUS-induced DOR. Our study establishes an animal model to investigate the impact of chronic stress on ovarian reserve function and sheds light on potential mechanisms underlying this phenomenon.

A novel alcohol+nicotine co-use self-administration procedure reveals sex differences and differential alteration of mesocorticolimbic TLR- and cholinergic-related neuroimmune gene expression in rats

Although alcohol and nicotine are two of the most commonly co-used drugs with upwards of 90% of adults with an alcohol use disorder (AUD) in the US also smoking, we don't tend to study alcohol and nicotine use this way. The current studies sought to develop and assess a novel alcohol + nicotine co-access self-administration (SA) model in adult male and female Long-Evans rats. Further, both drugs are implicated in neuroimmune function, albeit in largely opposing ways. Chronic alcohol use increases neuroinflammation via toll-like receptors (TLRs) which in turn increases alcohol intake. By contrast, nicotine produces anti-inflammatory effects, in part, through the monomeric alpha7 receptor (ChRNa7). Following long-term co-access (6 months), rats reliably administered both drugs during daily sessions, however males generally responded for more alcohol and females for nicotine. This was reflected in plasma analysis with translationally relevant intake levels of both alcohol and nicotine, making it invaluable in studying the effects of co-use on behavior and CNS function. Moreover, male rats show sensitivity to alterations in alcohol concentration whereas females show sensitivity to alterations in nicotine concentration. Rats trained on this procedure also developed an anxiogenic phenotype. Finally, we assessed alterations in neuroimmune-related gene expression in the medial prefrontal cortex - prelimbic, (mPFC-PL), nucleus accumbens core (AcbC), and ventral tegmental area (VTA). In the AcbC, where α7 expression was increased and β2 was decreased, markers of pro-inflammatory activity were decreased, despite increases in TLR gene expression suggesting that co-use with nicotine modulates inflammatory state downstream from the receptor level. By contrast, in mPFC-PL where α7 was not increased, both TLRs and downstream proinflammatory markers were increased. Taken together, these findings support that there are brain regional and sex differences with co-use of alcohol + nicotine SA and suggest that targeting nicotinic α7 may represent a novel strategy for treating alcohol + nicotine co-dependence.

Corticosterone administration immediately after peripuberty stress exposure does not prevent protracted stress-induced behavioral alterations

Stress-related disorders are commonly associated with abnormalities in hypothalamic-pituitary-adrenal (HPA) axis activity. Preliminary studies with cortisol administration in the aftermath of trauma suggest that this HPA axis hormone can potentially prevent maladaptive behavioral and biological stress responses. However, the efficacy of glucocorticoid administration during the peripuberty period has not been tested yet, although this lifetime is a critical time window in brain development and is highly sensitive to the harmful effects of stress. To further examine the short and long-lasting impact of glucocorticoids treatment given during the post-peripubertal stress period, the present study utilized a rat model of peripubertal stress-induced psychopathology and animals were subjected to a battery of tests to assess anxiety-like behaviors, exploratory behavior and reactivity to novelty at late adolescence and sociability, anhedonia and stress coping behaviors at adulthood. All the experiments were performed in males and females to evaluate the potential behavioral sex differences. Overall, our results demonstrated that rats exposed to peripubertal stress show decreased sociability in adulthood without differences in anxiety and depression-like behaviors. Moreover, this study shows that the administration of corticosterone after stress exposure at peripuberty does not prevent stress-induced behavioral alterations. However, we observed that some stress-induced behavioural alterations and corticosterone responses are sex-specific. Thus, the data obtained highlight that delineating sex differences in stress-related studies may ultimately contribute to the development of effective therapeutic interventions for each sex.

Applying the Research Domain Criteria to Rodent Studies of Sex Differences in Chronic Stress Susceptibility

Women have a 2-fold increased rate of stress-associated psychiatric disorders such as depression and anxiety, but the mechanisms that underlie this increased susceptibility remain incompletely understood. Historically, female subjects were excluded from preclinical studies and clinical trials. Additionally, chronic stress paradigms used to study psychiatric pathology in animal models were developed for use in males. However, recent changes in National Institutes of Health policy encourage inclusion of female subjects, and considerable work has been performed in recent years to understand biological sex differences that may underlie differences in susceptibility to chronic stress-associated psychiatric conditions. Here, we review the utility as well as current challenges of using the framework of the National Institute of Mental Health's Research Domain Criteria as a transdiagnostic approach to study sex differences in rodent models of chronic stress including recent progress in the study of sex differences in the neurobehavioral domains of negative valence, positive valence, cognition, social processes, and arousal.

Stress, hypothalamic-pituitary-adrenal axis, hypothalamic-pituitary-gonadal axis, and aggression

This comprehensive review explores the intricate relationship between the hypothalamic-pituitary-adrenal (HPA) axis, the hypothalamic-pituitary-gonadal (HPG) axis, and aggression. It provides a detailed overview of the physiology and functioning of these axes, as well as the implications for aggressive behavior. The HPA axis, responsible for the stress response, is activated in response to various stressors and can influence aggressive behavior. Glucocorticoids, such as cortisol, play a crucial role in stress-induced activation of the HPA axis and have been implicated in aggressive tendencies. Chronic stress can dysregulate the HPA axis, leading to alterations in cortisol levels and potentially contributing to aggressive behavior. The HPG axis, particularly the androgen hormone testosterone, is also closely linked to aggression. Animal and human studies have consistently shown a positive association between testosterone levels and aggression. The androgen receptors in the brain's neural circuitry play a critical role in modulating aggressive behavior. Interactions between the HPA and HPG axes further contribute to the regulation of aggression. Feedback mechanisms and crosstalk between these axes provide a complex system for the modulation of both stress and reproductive functions, which can impact aggressive behavior. Additionally,the influence of stress on reproductive functions, particularly the role of androgens in stress-induced aggression, adds further complexity to this relationship. The review also discusses the future directions and implications for clinical interventions. Understanding the neurobiological mechanisms underlying aggression requires integrating molecular, cellular, and circuit-level approaches. Translational perspectives, including animal models and human studies, can bridge the gap between basic research and clinical applications. Finally, therapeutic strategies for aggression-related disorders are explored, highlighting the importance of targeted interventions based on a comprehensive understanding of the interactions between the HPA and HPG axes. In conclusion, this review provides a comprehensive overview of the physiological and neurobiological mechanisms underlying aggression, with a specific focus on the interplay between the HPA and HPG axes. By elucidating the complex interactions between stress, hormones, and aggressive behavior, this research paves the way for future investigations and potential therapeutic interventions for aggression-related disorders.

A systematic review on the bidirectional relationship between trauma-related psychopathology and reproductive aging

Objective

Natural variation in ovarian steroid hormones across the female lifespan contributes to an increased risk for depressive and posttraumatic stress disorder (PTSD) symptoms in women. However, minimal work has focused on understanding the impacts of reproductive aging on the brain and behavioral health of trauma-exposed women. This systematic review examines the bidirectional relationship between trauma-related psychopathology and reproductive aging.

Method

Following PRISMA guidelines, a systematic review of PubMed, PsychInfo, and Medline databases was undertaken to identify controlled studies on how trauma history impacts psychopathology and menopause symptoms during reproductive aging.

Results

Twenty-one studies met the eligibility criteria, with only four utilizing the gold standard STRAW+ 10 criteria for defining reproductive aging stages. The peri and postmenopausal periods appear to be particularly vulnerable phases for individuals with trauma exposure. Menopause symptoms and trauma-related psychopathology symptom severity increase during reproductive aging with increases in the degree of trauma exposure. However, mechanistic insights that may explain this interaction are currently neglected in this area of research.

Conclusion

There is a significant lack of understanding regarding how reproductive aging and its related neuroendocrine changes impact the brain to influence PTSD and depression symptoms related to trauma exposure. This lack of basic understanding impedes the ability to identify, assess, and treat PTSD and depressive symptoms in trauma-exposed women most effectively, and mitigate the long-term consequences of these behavioral health symptoms on morbidity and mortality in aging women.

Hormone Regulation of Corticotropin-Releasing Factor Receptor 1 in the Female Mouse Brain

INTRODUCTION

Corticotropin-releasing factor receptor 1 (CRFR1) is a key regulator of neuroendocrine and behavioral stress responses. Previous studies have demonstrated that CRFR1 in certain hypothalamic and preoptic brain areas is modified by chronic stress and during the postpartum period in female mice, although the potential hormonal contributors to these changes are unknown.

METHODS

This study focused on determining the contributions of hormones associated with stress and the maternal period (glucocorticoids, prolactin, estradiol/progesterone) on CRFR1 levels using a CRFR1-GFP reporter mouse line and immunohistochemistry.

RESULTS

Administration of dexamethasone, an agonist of the glucocorticoid receptor, elevated CRFR1 in the anteroventral periventricular nucleus (AVPV/PeN) and paraventricular hypothalamus (PVN) with no changes found in the medial preoptic area (MPOA) or arcuate nucleus. Treatment with prolactin for 5 days elevated CRFR1 levels in the MPOA with no changes in other regions. Finally, we utilized the hormone-simulated pseudopregnancy (HSP) paradigm to mimic changes in estradiol and progesterone across pregnancy and the early postpartum period. Female mice receiving HSP treatment, as well as mice receiving HSP treatment that then underwent 5 days of estrogen withdrawal (EW), showed alterations in CRFR1 relative to control groups that mirrored changes previously reported in postpartum mice. Specifically, CRFR1 levels increased in the AVPV/PeN and decreased in the MPOA and PVN, with no changes found in the arcuate nucleus. HSP- and EW-treated mice also showed decreases in tyrosine hydroxylase-expressing neurons in the AVPV/PeN.

DISCUSSION/CONCLUSION

Overall, these hormone-induced changes in stress-regulating CRFR1 neurons may impact behavioral and neuroendocrine stress responses.

Neuroendocrine contribution to sex-related variations in adverse air pollution health effects

Air pollution exposure is ranked as a leading environmental risk factor for not only cardiopulmonary diseases but also for systemic health ailments including diabetes, reproductive abnormalities, and neuropsychiatric disorders, likely mediated by central neural stress mechanisms. Current experimental evidence links many air pollution health outcomes with activation of neuroendocrine sympathetic-adrenal-medullary and hypothalamic-pituitary-adrenal (HPA) stress axes associated with resultant increases in adrenal-derived hormone levels acting as circulating mediators of multi-organ stress reactions. Epidemiological and experimental investigations also demonstrated sex-specific responses to air pollutant inhalation, which may be attributed to hormonal interactions within the stress and reproductive axes. Sex hormones (androgens and estrogens) interact with neuroendocrine functions to influence hypothalamic responses, subsequently augmenting stress-mediated metabolic and immune changes. These neurohormonal interactions may contribute to innate sex-specific responses to inhaled irritants, inducing differing individual susceptibility. The aim of this review was to: (1) examine neuroendocrine co-regulation of the HPA axis by gonadal hormones, (2) provide experimental evidence demonstrating sex-specific respiratory and systemic effects attributed to air pollutant inhalation exposure, and (3) postulate proposed mechanisms of stress and sex hormone interactions during air pollution-related stress.

Post-traumatic stress disorder and symptoms in paediatric cancer survivors and their family nucleus: systematic review, meta-analysis and meta-regression

BACKGROUND

Various studies have highlighted the increased incidence and symptoms of depression and anxiety in paediatric cancer survivors (PCS). Yet no meta-analysis has focused on post-traumatic stress disorder (PTSD) or post-traumatic stress symptoms (PTSS) in PCS and their family nucleus.

AIMS

To evaluate the overall risk of PTSD and severity of PTSS in PCS and their family nucleus. Secondary objectives include identifying potential risk factors of PTSD and high PTSS.

METHOD

We systematically searched PubMed, Embase and PsycINFO for studies comparing the risk of PTSD and PTSS severity among PCS, their family nucleus and non-cancer controls. PRISMA reporting guidelines were followed. Random effects meta-analyses and meta-regressions were conducted.

RESULTS

From 1089 records, we included 21 studies. PCS have an increased risk of PTSD (risk ratio 2.36, 95% CI 1.37-4.06) and decreased PTSS severity (standardised mean difference -0.29, 95% CI -0.50 to -0.08). Subgroup analyses of other categorical study-level characteristics revealed that female PCS who were older at diagnosis and data collection had a significantly higher risk of PTSD. Meta-regression were insignificant. Family nucleus did not show a significantly increased risk of PTSD (risk ratio 1.13, 95% CI 0.59-5.00) and PTSS severity (standardised mean difference 0.53, 95% CI -0.00 to 1.06). Systematically reviewing studies on the family nucleus found that the majority reported a significantly increased risk of psychological trauma compared with the comparator. Lower education, income and social status were also risk factors.

CONCLUSIONS

Timely identification and interventions are imperative for policy makers and healthcare providers to prevent trauma from worsening in this population group.

Sex Differences in the Neuroendocrine Stress Response: A View from a CRH-Reporting Mouse Line

Corticotropin-releasing hormone (CRH) neurons within the paraventricular hypothalamic nucleus (PVH) play a crucial role in initiating the neuroendocrine response to stress and are also pivotal in coordination of autonomic, metabolic, and behavioral stress reactions. Although the role of parvocellular CRHPVH neurons in activation of the hypothalamic-pituitary-adrenal (HPA) axis is well established, the distribution and function of CRH-expressing neurons across the whole central nervous system are less understood. Stress responses activate complex neural networks, which differ depending on the type of stressor and on the sex of the individual. Because of the technical difficulties of localizing CRH neurons throughout the rodent brain, several CRH reporter mouse lines have recently been developed. In this study, we used Crh-IRES-Cre;Ai9 reporter mice to examine whether CRH neurons are recruited in a stressor- or sex-specific manner, both within and outside the hypothalamus. In contrast to the clear sexual dimorphism of CRH-mRNA-expressing neurons, quantification of CRH-reporting, tdTomato-positive neurons in different stress-related brain areas revealed only subtle differences between male and female subjects. These results strongly imply that sex differences in CRH mRNA expression occur later in development under the influence of sex steroids and reflects the limitations of using genetic reporter constructs to reveal the current physiological/transcriptional status of a specific neuron population. Next, we compared the recruitment of stress-related, tdTomato-expressing (putative CRH) neurons in male and female Crh-IRES-Cre;Ai9 reporter mice that had been exposed to predator odor. In male mice, fox odor triggered more c-Fos in the CRH neurons of the paraventricular hypothalamic nucleus, central amygdala, and anterolateral bed nucleus of the stria terminalis compared to females. These results indicate that male mice are more sensitive to predator exposure due to a combination of hormonal, environmental, and behavioral factors.

Sibling presence during fostering ameliorates endocrine stress profile changes in a social rodent species (Octodon degus) in a sex-specific manner

During early life, disruption of the parent-offspring bond can substantially impact development of offspring physiology and behavior. In rodents, it has been well-documented that parental separation, reduction in parental care, and cross-fostering can affect development of the endocrine stress response. For social species, however, several social factors may mitigate the stress of cross-fostering, such as remaining with other known adult caregivers or siblings. In this study, we cross-fostered a social rodent species (Octodon degus) with or without their siblings at postnatal day (PND) 8 and measured their endocrine stress response immediately after fostering (PND9) and at weaning (PND28). We found that female singly-fostered offspring displayed elevated baseline cortisol levels and reduced weight gain immediately after fostering. At weaning, female singly-fostered offspring continued to display elevated baseline cortisol levels compared to non-fostered female offspring, while singly-fostered males demonstrated weaker cortisol negative feedback strength compared to male offspring that were not fostered or were fostered with their siblings. These results suggest that sibling presence may help mitigate the stress of fostering, and that future studies should further examine other social conditions that may help reduce developmental consequences of long-term parental bond disruption.

Mechanisms underlying reproductive responses of Japanese quails to heat stress conditions

Exposure to heat stress can cause a significant increase in the death rate and disease susceptibility of poultry birds, ultimately impacting the profitability of the poultry industry. Despite being a more economical choice, Japanese quails (Coturnix japonica) are not immune to the harmful effects of heat stress. Quails may experience negative effects on their reproductive performance due to excessive reactive molecules caused by heat stress. However, they have developed various mechanisms to maintain their reproductive abilities in such conditions. The neuroendocrine system in birds plays a vital role in regulating their reproductive responses to thermal stress, and it is also connected to other environmental factors such as photoperiod that can impact their reproductive performance. Hormones are crucial in the complex interactions necessary for sexual maturation and reproductive responses to heat stress in Japanese quails living in stressful thermal conditions.

Stress-induced cortisol response predicts empathy for pain: The role of task-based connectivity between the insula and sensorimotor cortex during acute stress

Empathy for pain is a key driver of prosocial behavior and is influenced by acute psychosocial stress. However, the role of task-based brain connectivity during acute stress have been neglected. Hence, we aimed to explore the relationship between the magnitude of cortisol response to acute stress and empathy for pain, as well as the neural connectivity mechanisms involved. In this study, 80 healthy participants (37 women and 43 men) were exposed to the acute psychosocial stress paradigm (ScanSTRESS) and were scanned by functional magnetic resonance imaging. Saliva samples were collected to measure the magnitude of cortisol stress response. Subsequently, the participants took part in a pain-video task to assess their empathy for pain. Six participants were excluded because of physical discomfort or excessive head movement in all runs during the task-dependent fMRI scan. Therefore, 33 women and 41 men were included in data analysis. We found that empathy for pain was negatively correlated with the magnitude of cortisol stress response (r = -0.268, p = 0.018) and that the task-based connectivity between the salience network and sensorimotor network, including its sub-network and sub-region, was negatively correlated with the magnitude of cortisol stress response, and positively correlated with empathy for pain. Furthermore, task-based connectivity between the insula and the paracentral lobule mediates the effect of the stress-induced cortisol response on empathy for pain (indirect effect = -0.0152, 95% CI = [-0.036, -0.001], p = 0.036). Our research suggests that empathy is not only correlated with stress-induced glucocorticoids but also tied to the stress-induced reduced communication between basic and higher brain regions.

Sex-specific association of peripheral blood cell indices and inflammatory markers with depressive symptoms in early adolescence

BACKGROUND

Previous studies have reported the correlation of dysregulated blood cell indices and peripheral inflammatory markers with depression in adults but limited studies have examined this correlation in early adolescents.

METHODS

This study used data from the Chinese Early Adolescents Cohort Study, which was conducted in Anhui, China. Students' depression symptoms were repeatedly measured using the Chinese version of the Center for Epidemiological Studies Depression Scale for Children. Students' blood samples were collected in September 2019 and September 2021. The peripheral blood cell counts and inflammatory marker levels were determined using routine blood tests. Multivariable regression models were used to explore the associations between blood cell indices and adolescent depressive symptoms in both the whole sample and the sex-stratified samples.

RESULTS

The white blood cell (WBC) count, neutrophil count (NC), platelet (PLT) count, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio, and systemic immune inflammation index (SII) were positively correlated with the severity of depressive symptoms during follow-up. The mean corpuscular volume (MCV), mean hemoglobin (HGB) volume (MCH), and mean corpuscular HGB concentration (MCHC) exhibited negative temporal correlations with depressive symptoms. Additionally, several sex-specific blood cell markers were correlated with depression. Male adolescents with increased red blood cell (RBC) and female adolescents with decreased HGB levels and upregulated WBC, NC, NLR, and SII levels exhibited severe depressive symptoms at follow-up.

CONCLUSIONS

These findings suggested the potential usefulness of peripheral blood cell indices in the assessment of depression in early adolescents.

Sex-dependent effects of acute stress and alcohol exposure during adolescence on mRNA expression of brain signaling systems involved in reward and stress responses in young adult rats

BACKGROUND

Adolescent stress and alcohol exposure increase the risk of maladaptive behaviors and mental disorders in adulthood, with distinct sex-specific differences. Understanding the mechanisms underlying these early events is crucial for developing targeted prevention and treatment strategies.

METHODS

Male and female Wistar rats were exposed to acute restraint stress and intermittent alcohol during adolescence. We assessed lasting effects on plasma corticosterone (CORT) and adrenocorticotropic hormone (ACTH) levels, and mRNA expression of genes related to corticotropin releasing hormone (CRH), neuropeptide Y (NPY), corticoid, opioid, and arginine vasopressin systems in the amygdala and hypothalamus.

RESULTS

The main findings are as follows: (1) blood alcohol concentrations (BAC) increased after the final alcohol administration, but stressed males had lower BAC than non-stressed males; (2) Males gained significantly more weight than females; (3) Stressed females showed higher ACTH levels than non-stressed females, with no changes in males; (4) Stress increased CORT levels in males, while stressed, alcohol-treated females had lower CORT levels than non-stressed females; (5) CRH: Females had lower Crhr1 levels in the amygdala, while alcohol reduced Crhr2 levels in males but not females. Significant interactions among sex, stress, and alcohol were found in the hypothalamus, with distinct patterns between sexes; (6) NPY: In the amygdala, stress reduced Npy and Npy1r levels in males but increased them in females. Alcohol decreased Npy2r levels in males, with varied effects in females. Similar sex-specific patterns were observed in the hypothalamus; (7) Corticoid system: Stress and alcohol had complex, sex-dependent effects on Pomc, Nr3c1, and Nr3c2 in both brain regions; (8) Opioid receptors: Stress and alcohol blunted the elevated expression of Oprm1, Oprd1, and Oprk1 in the amygdala of males and the hypothalamus of females; (8) Vasopressin: Stress and alcohol interacted significantly to affect Avp and Avpr1a expression in the amygdala, with stronger effects in females. In the hypothalamus, alcohol increased Avp levels in females.

CONCLUSIONS

This study demonstrates that adolescent acute stress and alcohol exposure induce lasting, sex-specific alterations in systems involved in reward and stress responses. These findings emphasize the importance of considering sex differences in the prevention and management of HPA dysfunction and psychiatric disorders.

Sex differences in glutamate transmission and plasticity in reward related regions

Disruptions in glutamate homeostasis within the mesolimbic reward circuitry may play a role in the pathophysiology of various reward related disorders such as major depressive disorders, anxiety, and substance use disorders. Clear sex differences have emerged in the rates and symptom severity of these disorders which may result from differing underlying mechanisms of glutamatergic signaling. Indeed, preclinical models have begun to uncover baseline sex differences throughout the brain in glutamate transmission and synaptic plasticity. Glutamatergic synaptic strength can be assessed by looking at morphological features of glutamatergic neurons including spine size, spine density, and dendritic branching. Likewise, electrophysiology studies evaluate properties of glutamatergic neurons to provide information of their functional capacity. In combination with measures of glutamatergic transmission, synaptic plasticity can be evaluated using protocols that induce long-term potentiation or long-term depression. This review will consider preclinical rodent literature directly comparing glutamatergic transmission and plasticity in reward related regions of males and females. Additionally, we will suggest which regions are exhibiting evidence for sexually dimorphic mechanisms, convergent mechanisms, or no sex differences in glutamatergic transmission and plasticity and highlight gaps in the literature for future investigation.

Genetic deletion of NAPE-PLD induces context-dependent dysregulation of anxiety-like behaviors, stress responsiveness, and HPA-axis functionality in mice

The endocannabinoid (eCB) system regulates stress responsiveness and hypothalamic-pituitary-adrenal (HPA) axis activity. The enzyme N -acyl phosphatidylethanolamine phospholipase-D (NAPE-PLD) is primarily responsible for the synthesis of the endocannabinoid signaling molecule anandamide (AEA) and other structurally related lipid signaling molecules known as N -acylethanolamines (NAEs). However, little is known about how activity of this enzyme affects behavior. As AEA plays a regulatory role in stress adaptation, we hypothesized that reducing synthesis of AEA and other NAEs would dysregulate stress reactivity. To test this hypothesis, we evaluated wild type (WT) and NAPE-PLD knockout (KO) mice in behavioral assays that assess stress responsiveness and anxiety-like behavior. NAPE-PLD KO mice exhibited anxiety-like behaviors in the open field test and the light-dark box test after a period of single housing. NAPE-PLD KO mice exhibited a heightened freezing response to the testing environment that was further enhanced by exposure to 2,3,5-trimethyl-3-thiazoline (TMT) predator odor. NAPE-PLD KO mice exhibited an exaggerated freezing response at baseline but blunted response to TMT when compared to WT mice. NAPE-PLD KO mice also exhibited a context-dependent dysregulation of HPA axis in response to TMT in the paraventricular hypothalamic nucleus at a neuronal level, as measured by c-Fos immunohistochemstry. Male, but not female, NAPE-PLD knockout mice showed higher levels of circulating corticosterone relative to same-sex wildtype mice in response to TMT exposure, suggesting a sexually-dimorphic dysregulation of the HPA axis at the hormonal level. Together, these findings suggest the enzymatic activity of NAPE-PLD regulates emotional resilience and recovery from both acute and sustained stress.

Significance Statement

The endocannabinoid anandamide (AEA) regulates stress responsiveness and activity of the hypothalamic-pituitary-adrenal (HPA) axis. Currently, little is known about how an enzyme (i.e. N -acylphosphatidylethanolamine phospholipase-D (NAPE-PLD)) involved in the synthesis of AEA affects behavior. We hypothesized that genetic deletion of NAPE-PLD would dysregulate responsiveness to stress at a behavioral and neuronal level. Our studies provide insight into potential vulnerabilities to stress and anxiety that may result from dysregulation of the enzyme NAPE-PLD in people.

Simultaneous determination of 18 steroids in the hypothalamic pituitary gonadal axis based on UPLC-MS/MS with multimode ionization

To objectively quantify changes in steroid hormones in organisms caused by adverse environmental loads, we developed a simple and sensitive UPLC-MS/MS (ultra-performance liquid chromatography triple quadrupole mass spectrometry) method for the simultaneous determination of 18 steroid hormones on the HPG axis. This analytical method was based on liquid extraction and a multimode electrospray and atmospheric pressure chemical ionization (ESCi) source, which was optimized by mass spectrometry, liquid phase and pretreatment for the quantification of cholesterol (CH), aldosterone (A), cortisone (E), hydrocortisone (F), 21-deoxycortisol (21-DF), corticosterone (B), 11-deoxycortisol (11-DF), androstenedione (A2), estradiol (E2), estrone (E1), 2-methoxyestradiol (2-MeE2), 21-hydroxyprogesterone (21-OHP), 17-α hydroxyprogesterone (17α-OHP), testosterone (T), dehydroepiandrosterone (DHEA), progesterone (P4), dihydrotestosterone (DHT), and pregnenolone (P5). The method exhibits linearity in the analyte-concentration range 0.03-1000 μg mL-1 (r2 > 0.99), the spiked recoveries for the concentration range tested are 76.22-113.66%, and the relevant parameters of precision are 7.52-1.14%. Compared to other methods, this new method not only uses a small amount of serum (only 100 μL), but also permits the analysis of the challenging steroid, cholesterol. Furthermore, the method was successfully applied to the determination of steroids in Mus musculus, Carassius auratus, Rana catesbeiana Shaw, and Rana nigromaculata serum samples from randomly selected individuals. Therefore, this method is efficient and a very useful tool for assessing changes in steroid hormones.

Analyzing the Prevalence of Depression and Its Influencing Factors in Elderly Patients With Obstructive Sleep Apnea: A Machine Learning Approach

Objective: Depressive symptoms are prevalent and detrimental in elderly patients with obstructive sleep apnea (OSA). Understanding the factors influencing these symptoms is crucial. This study aims to use machine learning algorithms to identify the contributing factors in this population. Method: The National Health and Nutrition Examination Survey database provided the data for this study. The study includes elderly patients who are eligible for diagnostic evaluation for OSA. Logistic regression was used to screen their influencing factors, and random forest (RF), extreme gradient boosting (XGB), artificial neural network (ANN), and support vector machine (SVM) were utilized to 4 algorithms were used to construct depressive symptoms classification models, and the best model performance was selected for feature importance ranking. Influential factors included demographics (age, gender, education, etc.), chronic disease status (diabetes, hypertension, etc.), and laboratory findings (white blood cells, C-reactive protein, cholesterol, etc.). Result: Ultimately, we chose 1538 elderly OSA patients for the study, out of which 528 (34.4%) suffered from depressive symptoms. Logistic regression initially identified 17 influencing factors and then constructed classification models based on those 17 using RF, XGB, ANN, and SVM. We selected the best-performing SVM model [area under the curve (AUC) = 0.746] based on the AUC values of 0.73, 0.735, 0.742, and 0.746 for the 4 models. We ranked the variables in order of importance: General health status, sleep disorders, gender, frequency of urinary incontinence, liver disease, physical activity limitations, education, moisture, eosinophils, erythrocyte distribution width, and hearing loss. Conclusion: Elderly OSA patients experience a high incidence of depressive symptoms, influenced by various objective and subjective factors. The situation is troubling, and healthcare institutions and policymakers must prioritize their mental health. We should implement targeted initiatives to improve the mental health of high-risk groups in multiple dimensions.

Activation of P2X7 Receptor Mediates the Abnormal Ovulation Induced by Chronic Restraint Stress and Chronic Cold Stress

Chronic stress has become a major problem that endangers people's physical and mental health. Studies have shown that chronic stress impairs female reproduction. However, the related mechanism is not fully understood. P2X7 receptor (P2X7R) is involved in a variety of pathological changes induced by chronic stress. Whether P2X7R is involved in the effect of chronic stress on female reproduction has not been studied. In this study, we established a chronic restraint stress mouse model and chronic cold stress mouse model. We found that the number of corpora lutea was significantly reduced in the two chronic stress models. The number of corpora lutea indirectly reflects the ovulation, suggesting that chronic stress influences ovulation. P2X7R expression was significantly increased in ovaries of the two chronic stress models. A superovulation experiment showed that P2X7R inhibitor A-438079 HCL partially rescued the ovulation rate of the two chronic stress models. Further studies showed that activation of P2X7R signaling inhibited the cumulus expansion and promoted the expression of NPPC in granulosa cells, one key negative factor of cumulus expansion. Moreover, sirius red staining showed that the ovarian fibrosis was increased in the two chronic stress models. For the fibrosis-related factors, TGF-β1 was increased and MMP2 was decreased. In vitro studies also showed that activation of P2X7R signaling upregulated the expression of TGF-β1 and downregulated the expression of MMP2 in granulosa cells. In conclusion, P2X7R expression was increased in the ovaries of the chronic restraint-stress and chronic cold-stress mouse models. Activation of P2X7R signaling promoted NPPC expression and cumulus expansion disorder, which contributed to the abnormal ovulation of the chronic stress model. Activation of P2X7R signaling is also associated with the ovarian fibrosis changes in the chronic stress model.

Dysregulated zinc homeostasis and microadenomas in the anterior pituitary: pathological insights into suicide risk

Background

Suicide is a significant public health problem influenced by various risk factors, including dysregulation of the hypothalamus-pituitary-adrenal (HPA) axis. Zinc (Zn), essential for pituitary function in hormone synthesis and release, has been linked to suicide, with studies noting reduced serum levels and altered brain transport mechanisms. Despite Zn's crucial role in pituitary function and its involvement in suicidal behavior, information on pituitary Zn in suicide is scarce. Tumor cells modify Zn dynamics in tissues, and a previous report suggests microadenomas in the anterior pituitary as a risk factor for suicide.

Methods

Histopathological analysis with hematoxylin-eosin stain and histochemical techniques to assess Zn homeostasis were carried out on anterior pituitary postmortem samples from 14 suicide completers and 9 non-suicidal cases.

Results

Pituitary microadenomas were identified in 35% of suicide cases and none in the non-suicidal cases. Furthermore, compartmentalized Zn (detected via dithizone reactivity), but not free Zn levels (detected via zinquin reactivity), was lower in the suicide cases compared to the non-suicidal group.

Conclusion

This is the first report of a potential association between disrupted Zn homeostasis and microadenomas in the anterior pituitary as a feature in suicide and provides critical insights for future neuroendocrine Zn-related research.

Fetal endocrine axes mRNA expression levels are related to sex and intrauterine position

BACKGROUND

The hypothalamic-pituitary-adrenal (HPA) and -gonadal (HPG) axes are two major pathways that connect the neural and endocrine systems in vertebrates. Factors such as prenatal stress and maternal exposure to exogenous steroids have been shown to affect these pathways during fetal development. Another less studied factor is the transfer of hormones across fetuses in multifetal pregnancies. This form of transfer has been shown to influence the morphology, anatomy, physiology, and behavior of the offspring in litter-bearing mammals, an influence termed the intrauterine position (IUP) effect. In this study, we sought to delineate how the IUP effects HPA and HPG brain receptors, peptides, and enzymes (hereafter components) in utero and how these influences may differ between males and females.

METHODS

We utilized the unconventional model of culled free-ranging nutria (Myocastor coypus), with its large natural variation. We collected brain tissues from nutria fetuses and quantified the expression of key HPA and HPG components in three brain regions: prefrontal cortex, hypothalamus, and striatum.

RESULTS

We found an interaction between sex and IUP in the mineralocorticoid receptor (MR), gonadotropin-releasing hormone receptor (GNRHR), androgen receptor (AR), and estrogen receptor alpha (ESR1). IUP was significant in both gonadotropin-releasing hormone (GnRH) and its receptor GNRHR, but in different ways. In the hypothalamus, fetuses adjacent to same-sex neighbors had higher expression of GnRH than fetuses neighboring the opposite sex. Conversely, in the cortex, GNRHR exhibited the inverse pattern, and fetuses that were neighboring the opposite sex had higher expression levels than those neighboring the same sex. Regardless of IUP, in most components that showed significant sex differences, female fetuses had higher mRNA expression levels than male fetuses. We also found that HPA and HPG components were highly related in the early stages of gestation, and that there was an interaction between sex and developmental stage. In the early stages of pregnancy, female component expression levels were more correlated than males', but in the last trimester of pregnancy, male components were more related to each other than female's.

CONCLUSIONS

This study suggests that there are sexually different mechanisms to regulate the HPA and HPG axes during fetal development. Higher mRNA expression levels of endocrine axes components may be a mechanism to help females cope with prolonged androgen exposure over a long gestational period. Additionally, these findings suggest different coordination requirements of male and female endocrine axes during stages of fetal development.

Increased adrenocortical activity in patients with vasovagal syncope

OBJECTIVE

Syncope is a transient loss of consciousness resulting from cerebral hypoperfusion. Vasovagal syncope (VVS) is a form of orthostatic intolerance (OI). Its clinical signs such as dizziness and hypotension may mimic symptoms of adrenal insufficiency. The objective of this study was to evaluate the adrenal gland function in patients with vasovagal syncope after stimulation with synthetic adrenocorticotropic hormone (ACTH).

DESIGN

Case-control study on patients with VVS and healthy controls.

METHODS

The study involved 42 participants, including 27 patients diagnosed with VVS using the head-up tilt test and 15 healthy individuals with no history of syncope or any orthostatic symptoms. Serum cortisol and aldosterone concentrations were measured under basal conditions and at 30 and 60 min after intramuscular ACTH stimulation.

RESULTS

Patients with VVS had significantly higher cortisol levels at baseline (441 ± 143 vs. 331 ± 84.7 nmol/L, p = 0.01), at 30 min (802 ± 143 vs. 686 ± 105 nmol/L, p = 0.01) and at 60 min (931 ± 141 nmol/L vs. 793 ± 147 nmol/L, p = 0.001) after ACTH administration (Synacthen 250 μg). Plasma aldosterone increased after ACTH stimulation, but did not show significant differences among groups. Furthermore, there was also no significant correlation between cortisol levels and blood pressure or heart rate.

CONCLUSION

Patients diagnosed with VVS have higher cortisol levels both at baseline and after ACTH stimulation. This finding indicates that individuals with VVS have higher adrenocortical activity potentially as a response to the orthostatic stress induced by syncope, which acts as a stressful stimulus on the autonomic nervous system.

Associations among early life adversity, sleep disturbances, and depressive symptoms in adolescent females and males: a longitudinal investigation

BACKGROUND

Exposure to adversity early in life (ELA) has been associated with elevated risk for depression during adolescence, particularly for females; the mechanisms underlying this association, however, are poorly understood. One potential mechanism linking ELA and sex differences in depressive symptoms is sleep disturbances, which increase during adolescence and are more common in females. Here, we examined whether sleep disturbances mediate the association between ELA and increases in depressive symptoms during adolescence and whether this mediation differs by sex.

METHODS

224 (N = 132 females) youth were recruited at age 9-13 years and assessed every 2 years across three timepoints. At the first timepoint, we conducted extensive interviews about stressful events participants experienced; participants provided subjective severity ratings of events and we objectively scored the severity of each event. Self-reported sleep disturbances and depressive symptoms were assessed at all timepoints. We conducted linear mixed models to estimate both initial levels and changes in sleep disturbances and depressive symptoms, and moderated mediation analyses to test whether initial levels and/or changes in sleep disturbances mediated the association of ELA (objective and subjective) with increases in depressive symptoms across adolescence and whether the mediations differed by sex.

RESULTS

While higher initial levels and increases in sleep problems were uniquely associated with increases in depressive symptoms for males and females, they were related to ELA differently by sex. For females, greater ELA (both objectively and subjectively rated) was associated with higher initial levels of sleep problems, which in turn were associated with increases in depressive symptoms from early to late adolescence. In contrast, for males, ELA exposure was not associated with either initial levels of, or increases in, sleep problems.

CONCLUSIONS

These findings highlight the role of sleep disturbances during the transition to adolescence in mediating sex differences in the effects of ELA on depressive symptoms.

Brain-body mechanisms contribute to sexual dimorphism in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is the most common form of human motor neuron disease. It is characterized by the progressive degeneration of upper and lower motor neurons, leading to generalized motor weakness and, ultimately, respiratory paralysis and death within 3-5 years. The disease is shaped by genetics, age, sex and environmental stressors, but no cure or routine biomarkers exist for the disease. Male individuals have a higher propensity to develop ALS, and a different manifestation of the disease phenotype, than female individuals. However, the mechanisms underlying these sex differences remain a mystery. In this Review, we summarize the epidemiology of ALS, examine the sexually dimorphic presentation of the disease and highlight the genetic variants and molecular pathways that might contribute to sex differences in humans and animal models of ALS. We advance the idea that sexual dimorphism in ALS arises from the interactions between the CNS and peripheral organs, involving vascular, metabolic, endocrine, musculoskeletal and immune systems, which are strikingly different between male and female individuals. Finally, we review the response to treatments in ALS and discuss the potential to implement future personalized therapeutic strategies for the disease.

Clinical Factors and Biomarkers Associated with Depressive Disorders in Older Patients Affected by Chronic Kidney Disease (CKD): Does the Advanced Glycation End Products (AGEs)/RAGE (Receptor for AGEs) System Play Any Role?

Depressive disorders are highly prevalent among subjects suffering from chronic kidney disease (CKD). The aim of the present study is to evaluate clinical and biochemical factors associated with depressive disorders in a sample of older CKD patients, with a focus on advanced glycation end products (AGEs) and their soluble receptors (sRAGEs). A total of 115 older subjects affected by CKD (stages 3 to 5, not in dialysis) were selected for this study. These patients were divided into two groups according to the presence of depressive disorders defined by a score ≥ 10 on the 30-item Geriatric Depression Scale (GDS). The two groups were compared by independent sample t tests for continuous variables and χ2 tests for qualitative ones. Significant variables at univariate analyses were then inserted as predictors of a binary logistic regression model, with the presence or absence of depressive disorders as a dependent variable. The binary logistic regression model showed that patients with concomitant depressive disorders were more frequently of female gender (p < 0.01) and had lower MCP1 (p < 0.01) and AGE circulating levels (p < 0.01) than their counterparts. Depressive disorders in older CKD patients are more prevalent in women and seem to be inversely associated with systemic inflammation and circulating AGEs.

Tao-Hong-Si-Wu-Tang Improves the Depressive-like Behaviors in Mice Experiencing Perimenopausal Depression Through Modulating Activity of the Hypothalamic-Pituitary-Adrenal-Ovary Axis and Activating the BDNF-TrkB-CREB Signaling Pathway

Tao-Hong-Si-Wu-Tang (THSWT), a traditional Chinese herbal remedy, is commonly utilized for the treatment of female perimenopausal depression through regulating menstruation, but the mechanism remains unknown. In this study, ICR mice were randomly divided into six groups: low, medium, and high dose of THSWT (0.5, 1.5, and 4.5 g/kg), soy isoflavone (250 mg/kg), ovariectomy group, and control group. All mice, except the control group, had ovaries removed and were exposed to hypoxic stimulation for 28 days to establish a perimenopausal depression mice model. The mice, having unrestricted access to food and water, were administered THSWT treatment for a duration of 14 days. The Western blotting and Enzyme linked immunosorbent assay kits were used to determine protein and hormone levels, respectively. Experimental results showed that THSWT reduced the immobility time of mice from 150.8 s to 104.9 s in the tail suspension test, and it decreased the immobility time of mice from 165.7 s to 119.0 s in the forced swimming test, outperforming the results obtained with soy isoflavones. In addition, THSWT upregulated the protein expression of follicle-stimulating hormone receptor and downregulated the protein expression of corticotropin-releasing hormone-receptor 1 in the hippocampus. Compared with the oophorectomized group, treatment with THSWT decreased the levels of corticosterone and adrenocorticotropic hormone in serum by 173.7 and 23.4 ng/mL, respectively. These findings showed that THSWT could stimulate the perimenopausal nerve tissue and regulate the level of serum hormones in mice. THSWT exhibited promising potential as a viable alternative drug for hormone treatment of perimenopause in clinical use.

The role of resilience in the relationship between stress and alcohol

Stress plays a well-documented role in alcohol consumption and the risk for developing alcohol use disorder. The concept of resilience - coping with and successfully adapting to stressful life experiences - has received increasing attention in the field of addiction research in recent decades, and there has been an accumulation of evidence for resilience as a protective factor against problematic alcohol consumption, risk for alcohol use disorder, disorder severity, and relapse. The conceptual and methodological approaches used in the generation of this evidence vary considerably across investigations, however. In light of this, we carried out this review in order to provide a more thorough understanding of the meaning and scope of resilience, what factors contribute to resilience, how it is measured, and how it relates to alcohol-associated phenotypes. Implications for treatment through the use of resilience-building interventions are likewise discussed, as well as implications for future research on the role of resilience in the etiology and clinical outcomes of alcohol use disorder.

Social status predicts physiological and behavioral responses to chronic stress in rhesus monkeys

Investigating the underlying factors that cause differential individual responses to chronic stress is crucial for developing personalized therapies, especially in the face of pandemics such as COVID-19. However, this question remains elusive, particularly in primates. In the present study, we aimed to address this question by utilizing monkeys as a model to examine the impacts of social rank on stress levels and physiological and behavioral responses to chronic stress primarily caused by social isolation at both the individual and group levels. Our results showed that high-ranking animals were more susceptible to chronic stress. After exposure to chronic stress, although social hierarchies remained the same, the colonies exhibited more harmonious group relationships (e.g., more prosocial behaviors), with notable contributions from low-ranking animals. Overall, this study deepens our understanding of how social status shapes responses to chronic stress and sheds light on developing tailored and personalized therapies for coping with chronic stress.

Pre-exercise cryotherapy reduces myoglobin and creatine kinase levels after eccentric muscle stress in young women

Introduction: The aim of this study was to investigate the effect of pre-exercise whole-body cryotherapy (WBC) on muscle damage indicators following eccentric treadmill exercise in young women. Methods: Twenty-seven participants underwent two 1-h downhill treadmill runs, replicating 60% of their maximal oxygen uptake, with a 4-week intermission for recovery and treatment application. In this intermission, one group underwent 20 sessions of WBC, delivered five times a week at -120°C for 3 min each, while the comparison group received no such treatment. Markers of muscle injury-serum myoglobin concentration, creatine kinase and lactate dehydrogenase activity and also uric acid, and cell-free DNA concentration-were measured before and after downhill runs. Results: The study observed a notable reduction in post-exercise myoglobin and CK levels in the WBC group after the second running session. Discussion: The results suggest that WBC can have a protective effects against muscle damage resulting from eccentric exercise.

The effect of late-life environmental enrichment on stress and anxiety: The role of sex and age-related differences in coping with aversive stimuli

Anxiety significantly diminishes the quality of life in older adults, and the drugs used for its treatment often come with risky side effects. Non-pharmacological protocols could be valuable, but more research is needed in this area. Environmental enrichment induces positive effects on anxiety-like behavior in young and adult animals; whether the same happens in aged animals is still elusive. The aged brain undergoes changes that contribute to make it "fragile" and consequently even mild, potentially positive stimuli can trigger dyshomeostasis, worsening rather than ameliorating functioning. Here, by combining behavioral analysis and measurement of serum and brain corticosterone levels, we show that late-life environmental enrichment can induce eustress or distress, depending on sex and hypothalamic-pituitary-adrenal axis function. These findings pave the way for optimizing outcomes and minimizing undesired effects in the clinical setting, underscoring the need to overcome the limits of gender medicine and emphasizing the crucial role of individually tailored therapies.

The association between family cohesion and depression: A systematic review and meta-analysis

BACKGROUND

Many studies have analyzed the association between family cohesion and depression, but there are different views and the results are inconsistent. It is necessary to use meta-analysis to explore the association between family cohesion and depression and its influencing factors.

METHODS

Chinese database (China National Knowledge Infrastructure) and English databases (ERIC, MEDLINE, Web of Science Core Collection, Elsevier SD, PsycINFO, PsycArticles, and ProQuest dissertations and theses) were searched for articles published by November 2023. Measurements of family cohesion and depression, study design, age, gender, cultural background, and sampling year were analyzed as moderators. Meta-analysis was performed using the random effects model in CMA3.0 software.

RESULTS

A total of 71 studies (90,023 participants) were included in this study. The meta-analysis revealed a significant negative correlation between family cohesion and depression (r = -0.31, 95 % CI [-0.35, -0.27]). The association was moderated by measurements of family cohesion and depression, design type, and cultural background, but not by age, gender, or sampling year.

LIMITATIONS

The sample size included in this study is relatively small in European and African cultures, making it challenging to analyze cultural differences in the study results at present comprehensively.

CONCLUSIONS

The findings contribute to the ongoing debate between Social Support Theory and The Circumplex Model, showing that individuals with lower family cohesion tend to experience higher levels of depression.

Divergent effects of sex on hippocampal subfield alterations in drug-naive patients with major depressive disorder

BACKGROUND

The hippocampus is a crucial brain structure in etiological models of major depressive disorder (MDD). It remains unclear whether sex differences in the incidence and symptoms of MDD are related to differential illness-associated brain alterations, including alterations in the hippocampus. This study investigated divergent the effects of sex on hippocampal subfield alterations in drug-naive patients with MDD.

METHODS

High-resolution structural MR images were obtained from 144 drug-naive individuals with MDD early in their illness course and 135 age- and sex-matched healthy controls (HCs). Hippocampal subfields were segmented using FreeSurfer software and analyzed in terms of both histological subfields (CA1-4, dentate gyrus, etc.) and more integrative larger functional subregions (head, body and tail).

RESULTS

We observed a significant overall reduction in hippocampal volume in MDD patients, with deficits more prominent deficits in the posterior hippocampus. Differences in anatomic alterations between male and female patients were observed in the CA1-head, presubiculum-body and fimbria in the left hemisphere. Exploratory analyses revealed different patterns of clinical and memory function correlations with histological subfields and functional subregions between male and female patients primarily in the hippocampal head and body.

LIMITATIONS

This cross-sectional study cannot clarify the causality of hippocampal alterations or their association with illness risk or onset.

CONCLUSIONS

These findings represent the first reported sex-specific alterations in hippocampal histological subfields in patients with MDD early in the illness course prior to treatment. Sex-specific hippocampal alterations may contribute to diverse sex differences in the clinical presentation of MDD.

Childhood adversity is associated with anxiety and depression in older adults: A cumulative risk and latent class analysis

BACKGROUND

The long-lasting influence of childhood adversity on mental health is well documented; however empirical research examining how this association extends into older adults is limited. This study operationalises adversity using cumulative risk and latent class analysis (LCA) models to assess how adversity exposure and typologies may predict anxiety and depression in older adults.

METHODS

Data came from the Personality and Total Health (PATH) Through Life Project (N = 2551, age 60-66). Participants retrospectively reported their childhood experiences of domestic adversity on a 17-item scale. Mental health was measured using four validated questionnaires of depression and anxiety.

RESULTS

Linear and generalised additive models (GAM) indicated a dose-response relationship, where a greater number of cumulative adversities were associated with poorer scores on all four mental health measures. LCA identified a four-class solution; with high adversity and high parental dysfunction being associated with poorer mental health outcomes while moderate parental dysfunction and low adversity groups scored at healthy levels. Women reported higher overall anxiety than men, but no notable interactions between ACEs and gender were observed. Patterns revealed by LCA were similar to patterns shown by the cumulative risk model.

LIMITATIONS

There is a large time gap from childhood to assessment, making our study susceptible to recall bias. Also, our findings were based on cross-sectional data, limiting causal inferences.

CONCLUSION

Childhood adversity had independent and additive contributions to depression and anxiety in older adulthood, and both cumulative risk and person-centred approaches captured this relationship.

The lived experiences and treatment needs of women with opioid use disorder and posttraumatic stress symptoms: A mixed methods study

INTRODUCTION

Women show a gender-specific risk for co-occurring opioid use disorder (OUD) and posttraumatic stress disorder (PTSD). Expert groups have called for the development of integrated treatments for women with OUD/PTSD, but there remains limited information on such interventions.

METHODS

This mixed-methods study interviewed and surveyed 10 women with current or past OUD and co-occurring posttraumatic stress symptoms (PTSS) and 16 providers who work with these women. Interviews and surveys queried patient participants' and providers' experiences of OUD/PTSS and how to best design an integrated, trauma-focused treatment for OUD/PTSD.

RESULTS

Patient participants (90 % white, 90 % mothers, Mage = 45.70) met criteria for severe, lifetime OUD and 40 % met a provisional diagnosis for PTSD. Four themes emerged for participants' experiences of OUD/PTSS: 1) numerous stressors; 2) shame; 3) multiple motivations to use opioids; and 4) a cycle of trauma and opioid use. Four themes emerged regarding patient participants' perceptions on the development of an OUD/PTSD treatment: 1) mixed attitudes towards medications for OUD; 2) barriers to treatment (e.g., insufficient treatments and contextual factors); 3) treatment facilitators (e.g., social support); and 4) preferences in treatment (e.g., trauma-focused, gender-focused, family content, ambivalence around group therapy). Providers (Mage = 38.94) were primarily white women (76.5 %). Two themes emerged from their experiences working with women with OUD/PTSS: 1) perceiving women to use opioids to regulate emotions and 2) gender differences in trauma types. Three themes emerged for providers' perceptions on the development of an OUD/PTSD treatment: 1) barriers to treatment (e.g., chaotic lives, contextual factors, family); 2) treatment facilitators (e.g., trust and external motivations); and 3) desired treatment modifications (e.g., stabilization, early skills in therapy, flexibility in therapy, social supports, safety guidelines, and assistance in identifying an index trauma). Most participants (90.0 %) and providers (93.5 %) preferred working on OUD/PTSD symptoms simultaneously rather than separately.

CONCLUSIONS

Findings demonstrate the need to modify integrated treatments to meet the preferences of providers and women with OUD/PTSS and OUD/PTSD. Treatments should consider therapeutic content, structure, contextual factors, social support, and PTSD severity to enhance uptake and reach.

Hippocampus diffusivity abnormalities in classical trigeminal neuralgia

Introduction

Patients with chronic pain frequently report cognitive symptoms that affect memory and attention, which are functions attributed to the hippocampus. Trigeminal neuralgia (TN) is a chronic neuropathic pain disorder characterized by paroxysmal attacks of unilateral orofacial pain. Given the stereotypical nature of TN pain and lack of negative symptoms including sensory loss, TN provides a unique model to investigate the hippocampal implications of chronic pain. Recent evidence demonstrated that TN is associated with macrostructural hippocampal abnormalities indicated by reduced subfield volumes; however, there is a paucity in our understanding of hippocampal microstructural abnormalities associated with TN.

Objectives

To explore diffusivity metrics within the hippocampus, along with its functional and structural subfields, in patients with TN.

Methods

To examine hippocampal microstructure, we utilized diffusion tensor imaging in 31 patients with TN and 21 controls. T1-weighted magnetic resonance images were segmented into hippocampal subfields and registered into diffusion-weighted imaging space. Fractional anisotropy (FA) and mean diffusivity were extracted for hippocampal subfields and longitudinal axis segmentations.

Results

Patients with TN demonstrated reduced FA in bilateral whole hippocampi and hippocampal body and contralateral subregions CA2/3 and CA4, indicating microstructural hippocampal abnormalities. Notably, patients with TN showed significant correlation between age and hippocampal FA, while controls did not exhibit this correlation. These effects were driven chiefly by female patients with TN.

Conclusion

This study demonstrates that TN is associated with microstructural hippocampal abnormalities, which may precede and potentially be temporally linked to volumetric hippocampal alterations demonstrated previously. These findings provide further evidence for the role of the hippocampus in chronic pain and suggest the potential for targeted interventions to mitigate cognitive symptoms in patients with chronic pain.

Gonads under stress: A systematic review and meta-analysis on the effects of acute psychosocial stress on gonadal steroids secretion in humans

Animal research has shown that the hypothalamus-pituitary-gonadal (HPG) axis is inhibited by (chronic and/or severe) stress, which can lead to impaired fertility and reproductive functioning, presumably caused by the inhibition of gonadal steroid secretion and in interactions with glucocorticoids. However, what has not been clarified is how acute psychosocial stress modulates gonadal steroid secretion in humans. Here we summarize the experimental research on the acute effects of stress on the secretion of gonadal steroids in humans. A systematic literature search revealed 21 studies (with N=881 individuals) measuring testosterone, progesterone or estradiol in response to a standardized acute laboratory stressor in healthy humans. Both our literature review and quantitative meta-analysis suggest that in humans, acute stress stimulates rather than inhibits HPG axis activity, although there is a considerable heterogeneity in the reported methods and results. Increased gonadal steroids in response to acute stress contrasts with many animal studies reporting the opposite pattern, at least regarding severe and/or chronic stressors. We discuss methodological issues and challenges for future research and hope to stimulate experimental studies within this area. A better understanding of these mechanisms is needed, and may have important implications for health and disease, as well as the modulation of various behaviors by acute stressors.

The Effectiveness and Safety of Acupuncture for Mammary Hyperplasia: A Systematic Review and Meta-Analysis

Objective

This study aims to systematically evaluate the effectiveness and safety of acupuncture in treating mammary hyperplasia.

Methods

A comprehensive search was conducted in various databases, including PubMed, Web of Science, Cochrane Library, Embase, SinoMed, China National Knowledge Infrastructure (CNKI), Wanfang, and VIP Database, from their inception until July 2023. Only randomized controlled trials (RCTs) researching the use of acupuncture for mammary hyperplasia were included. Quality assessment and data analysis were performed using RevMan 5.3 software.

Results

Eight RCTs, comprising 573 patients, were included in this analysis. The meta-analysis revealed that in the acupuncture group, the experimental group was better than the control group in improving breast pain, breast lump extent, and the texture of breast lump (P=0.0007, I2=61%; P=0.02, I2=0%; P=0.0002, I2=0%). We found that both could be improved, but after statistical analysis, there was no significant advantage in the acupuncture group compared with the patent Chinese medicine group (p>0.05).

Conclusion

Acupuncture appears to be an effective and safe treatment for mammary hyperplasia, providing pain relief and reducing mass volume, texture, and extent. However, the insufficient quality of the available evidence indicates the need for further methodologically rigorous and convincingly designed studies to determine the efficacy and safety of acupuncture in the treatment of breast hyperplasia.

Seasonal Hair Glucocorticoid Fluctuations in Wild Mice (Phyllotis darwini) within a Semi-Arid Landscape in North-Central Chile

Mammals in drylands face environmental challenges exacerbated by climate change. Currently, human activity significantly impacts these environments, and its effects on the energy demands experienced by individuals have not yet been determined. Energy demand in organisms is managed through elevations in glucocorticoid levels, which also vary with developmental and health states. Here, we assessed how anthropization, individual characteristics, and seasonality influence hair glucocorticoid concentration in the Darwin's leaf-eared mouse (Phyllotis darwini) inhabiting two areas with contrasting anthropogenic intervention in a semi-arid ecosystem of northern Chile. Hair samples were collected (n = 199) to quantify hair corticosterone concentration (HCC) using enzyme immunoassays; additionally, sex, body condition, and ectoparasite load were recorded. There were no differences in HCC between anthropized areas and areas protected from human disturbance; however, higher concentrations were recorded in females, and seasonal fluctuations were experienced by males. The results indicate that animals inhabiting semi-arid ecosystems are differentially stressed depending on their sex. Additionally, sex and season have a greater impact on corticosterone concentration than anthropogenic perturbation, possibly including temporal factors, precipitation, and primary production. The influence of sex and seasonality on HCC in P. darwini make it necessary to include these variables in future stress assessments of this species.

Sex differences of post-Covid patients undergoing outpatient pulmonary rehabilitation

BACKGROUND

Following years of pandemic severe acute respiratory syndrome coronavirus 2 infections labelled Covid-19, long lasting impairment summarized as post-Covid syndrome (PCS) challenges worldwide healthcare. Patients benefit from rehabilitation programs, but sex specific aspects of improvement remain little understood. The aim of the study was to assess whether women and men differ in response to outpatient pulmonary rehabilitation for PCS.

METHODS

263 (54.4% female) patients partaking in outpatient pulmonary rehabilitation (OPR) due to PCS between March 2020 and July 2022 were included in a prospective observational cohort study. Outcomes were assessed at baseline and before discharge from OPR and included six-minute walking distance (6MWD), 1-second forced expiratory volume (FEV1), diffusion capacity for carbon monoxide, maximal inspiratory pressure (MIP), dyspnea (medical research council scale), and post-Covid functional status scale (PCFS). Sexspecific changes in outcomes following OPR were assessed by linear mixed model and presented as mean differences (MD) with 95% confidence intervals. Linear regression was applied to test whether 6MWD correlates with PCFS and the minimal clinically important difference (MCID) in 6MWD regarding an improvement of at least one point in PCFS was computed with logistic regression.

RESULTS

Significant improvement throughout OPR was observed for all outcomes (all p < 0.0001). Despite less severe Covid-19 infections, PCFS scores remained higher in females after OPR (p = 0.004) and only 19.4% of women compared to 38.5% of men achieved remission of functional impairment. At baseline as well as after OPR, females showed higher symptom load compared to men in dyspnea (p = 0.0027) and scored lower in FEV1 (p = 0.009) and MIP (p = 0.0006) assessment. Performance in 6MWD was comparable between men and women. An increase of 35 m in 6MWD was computed as minimal clinically important difference to improve functional impairment.

CONCLUSION

Both subjective symptoms such as fatigue and dyspnea and objective impairment in performance in pulmonary function were more frequently observed among women. Despite improvement throughout OPR in both women and men, the sex-gap in symptom load could not be closed as women less often achieved remission from functional impairment due to PCS. Intensified treatment of these symptoms should be considered in women undergoing rehabilitation for PCS.