Sex differences in cortisol levels in depression: A systematic review and meta-analysis

Sex differences in the murine HPA axis after acute and repeated restraint stress

Chronic stress and stress-related mental illnesses such as major depressive disorder (MDD) constitute some of the leading causes of disability worldwide with a higher prevalence in women compared to men. However, preclinical research into stress and MDD is heavily biased toward using male animals only. Aberrant activity of the hypothalamic-pituitary-adrenal (HPA) axis has been linked to the development of MDD and several animal models of MDD have been established based on HPA axis dysregulation. In the present study, we compared stress biomarkers and behavior of male and female mice after acute and chronic restraint stress to investigate potential effects of sex differences in the stress response. Further, the validity of the interrupted repeated restraint stress (IRRS) model as an animal model for the HPA axis disturbances seen in MDD was assessed. After acute stress, female mice showed increased corticosterone secretion and changes in molecular markers suggesting increased HPA axis feedback sensitivity. Acute stress-induced signs of anxiety-like behavior were observed in male mice only suggesting that female mice may be more resilient to the anxiogenic effects of acute stress. Males and females responded similarly to IRRS with no sustained perturbations in HPA axis biomarkers. The IRRS model did not adequately translate to the changes reported in MDD with HPA axis overactivity and more severe perturbation models are likely needed. However, in alignment with previous studies, these data support that there are important sex differences in the HPA axis and that these may contribute to the etiology of stress-related psychiatric disorders.

Advanced cortisol detection: A cMWCNTs-enhanced MB@Zr-MOF ratiometric electrochemical aptasensor

A ratiometric electrochemical aptasensor was developed for ultra-sensitive detection of cortisol using aptamer (Apt) as recognition element, methylene blue (MB) as signal probe, and zirconium metal-organic framework (Zr-MOF) as carrier loaded with abundant MB for signal amplification. The carboxylated multi-walled carbon nanotubes (cMWCNTs)-modified Au electrode showed excellent electrochemical performance to immobilize complementary DNA (cDNA) for hybridizing with MB@Zr-MOF-Apt via amide bonds. In the presence of cortisol, it would compete with cDNA for binding the Apt, resulting in the detachment of MB@Zr-MOF-Apt complex from the electrode surface, and the electrochemical signal of MB was decreased, while that of [Fe(CN)6]3-/4- was basically unchanged. The ratio of the electrochemical signals of [Fe(CN)6]3-/4- to MB was proportional to the cortisol concentration. Due to the greatly enhanced conductivity of the cMWCNTs-decorated Au electrode and the largely improved EC signals of Zr-MOF encapsulated MB probes, this ratiometric electrochemical aptasensor offered high sensitivity with an ultra-low detection limit of 0.0046 nM and a wide linearity of 0.01-1000 nM, as well as satisfactory accuracy with recoveries of 93.79-106.76 % in artificial sweat samples, providing a potential strategy for the detection of more trace hormones in different clinical samples by simply replacing the corresponding aptamers.

Physical activity alleviates mental health problems related to bullying through moderating rumination

BACKGROUND

Physical activity and experiencing bullying is a protective and risk factor for mental health, respectively. Adolescents who suffer from bullying tend to be trapped in rumination, leading to mental health problem. However, the interaction among them from the perspective of increasing protective factors and reducing risk factors is unclear. This study explored whether rumination mediated the association between experiencing bullying and mental health problems and the moderating role of physical activity.

METHOD

This study investigated 13,983 students from high school in Jiangxi Province, China, and assessed for experiencing bullying, rumination, mental health problems (depressive, anxiety, and insomnia symptoms), and physical activity. Moderated mediation analysis was conducted using R software (version 4.1.1).

RESULTS

Significant differences were observed in rumination, physical activity and mental health problems between adolescents who have experienced bullying and those who have not (p < 0.001). Rumination mediated the relationship between experiencing bullying and depressive symptoms (β= 0.45, 95 % CI [0.42, 0.48]), anxiety symptoms (β= 0.37, 95 % CI [0.35, 0.39]), and insomnia symptoms (β= 0.36, 95 % CI [0.33, 0.38]). Moreover, physical activity moderated the relationship between rumination and depressive symptoms (coeff = -0.03, p < 0.001), anxiety symptoms (coeff = -0.02, p < 0.001), and insomnia symptoms (coeff = -0.01, p < 0.001).

CONCLUSIONS

Rumination and physical activity mediated and moderated, respectively, the relationship between experiencing bullying and adolescents' mental health problems. These findings indicate that schools and society should establish a campus bullying early warning system, pay attention to bullying incidents and promote physical activity.

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.

Cortisol in schizophrenia spectrum disorders: A comprehensive meta-analysis

Schizophrenia spectrum disorders (SSD) are characterized by alterations in cortisol levels across various parameters, including stress reactivity, hair cortisol, and baseline levels, which may be influenced by antipsychotic treatment. To provide a comprehensive overview of cortisol dysregulation in SSD, we conducted meta-analyses assessing (1) the effects of antipsychotic treatment in SSD patients, and additionally comparing cortisol in SSD patients versus healthy controls (HC) (2) following stress induction (metabolic, physiological, psychological stressors), (3) in hair and (4) baseline levels. Systematic literature searches in PubMed, Web of Science, and PsycINFO (November 2024) identified 121 studies (9049 SSD patients) for inclusion. Meta-analytic results revealed that antipsychotic treatment significantly reduced cortisol levels in SSD (k = 16, g = -0.480, 95 % CI [-0.818, -0.142], p = 0.005). Additionally, compared to HC, SSD was associated with reduced cortisol suppression following dexamethasone exposure (k = 9, g = 0.299, 95 % CI [0.091, 0.507], p = 0.005) and with elevated baseline cortisol levels in the morning (k = 71, g = 0.38, 95 % CI [0.210, 0.546], p < 0.001) and evening (k = 11, g = 0.368, 95 % CI [0.076, 0.661], p = 0.014). However, there were no significant group differences in afternoon baseline cortisol, hair cortisol or cortisol reactivity to stress (p > 0.05). These findings offer a detailed understanding of cortisol alterations in SSD and improve our understanding of HPA axis dysregulation in SSD.

Salivary hormones in depression: the future in diagnosis and treatment

Depression is associated with a significant burden on individuals, families, and communities. It leads to impaired social and occupational functioning, increased disability, decreased quality of life, and higher mortality rates, often due to suicide. A recent estimate from the World Health Organization (WHO) states that over 280 million people of all ages suffer from depression, which equals approximately 3.8% of the world population. Despite effective treatments for mental disorders, a dire treatment gap persists. This treatment gap could be reduced by effective and available diagnostic methods that have the potential to aid in depression diagnosis, stratification of patient subgroups, and treatment monitoring. In this regard, salivary hormones have been studied as potential markers for different types and etiologies of depression due to the convenience of non-invasive sample collection and their correlation with certain aspects of mood and mental health. The literature suggests they can help clinicians assess an individual's stress response, hormonal imbalances, and treatment response, leading to more personalized and effective interventions. In this review, we offer an up-to-date look at all studied salivary hormones associated with depression, including Cortisol, Melatonin, Oxytocin, Serotonin, Dehydroepiandrosterone, Testosterone, Progesterone, and Estradiol.

Physiology-Related Variations in the Blood Hormone and Metabolome of Endangered Hog Deer (Axis porcinus)

Background/Objectives: The hog deer (Axis porcinus) is an endangered species facing significant threats from habitat loss and fragmentation, with only captive populations remaining in China. Expanding breeding programs and restoring wild populations are critical strategies for the species' conservation. Achieving this requires the development of an effective health database and the identification of molecular biomarkers for their physiological traits. Methods: In this study, we present the largest blood metabolomics dataset to date for captive hog deer, comprising 73 healthy individuals. We conducted targeted metabolomics to quantify blood hormone levels and untargeted metabolomics to characterize blood metabolic profiles, aiming to evaluate the associations of sex, age, and weight with metabolic profiles. Results: Our results reveal distinct growth patterns between females and males, with males reaching their body weight plateau at a larger size. We observed significant sex differences (p < 0.05) in blood hormones and metabolic profiles. Females exhibited higher levels of progesterone, hydroxyprogesterone, stress hormones (e.g., cortisol), and proline, while males had higher levels of testosterone, uric acid, phenylalanine, and guanidinosuccinic acid. Notably, body weight emerged as a more important factor than gender in explaining variations in the metabolome, particularly in males. Several blood biomarkers were identified as correlating with age and body weight. Specifically, blood progesterone levels in females were linked to both age and body weight, while in males, uric acid, prolylhydroxyproline, and 3-methylhistidine were associated with these factors. The potential significance of these results for the artificial breeding and conservation of hog deer were discussed. Conclusions: Our study provides a metabolic reference for identifying abnormal individuals and offers potential biomarkers for determining the gender, age, and body weight of hog deer. These findings may have significant implications for the artificial breeding and conservation efforts of the species.

Subjective and objective stress during body exposure: a comparison of adolescents with anorexia nervosa versus high body dissatisfaction

Objective

Body dissatisfaction (BD) is a risk factor for the development of an eating disorder (ED) and a negative predictor for treatment outcome in adolescents with anorexia nervosa (AN). As a clinical core symptom and a relevant maintaining factor of AN, body image disturbance and BD are highly relevant target variables for therapeutic interventions. Body exposure (BE) was found as being effective for reducing BD in adolescents with EDs and high BD. However, the underlying mechanisms of BE are still not clear, with habituation processes being discussed as one possible mechanism.

Methods

Affective and neurobiological processes during a four-session computer-based BE intervention were investigated. Within a controlled design comparing adolescents with AN (n = 34) vs. adolescent patients with high BD (n = 17) but without a diagnosed ED, subjective (stress ratings; 11-point Likert scale) and objective (salivary cortisol and alpha-amylase [sAA]) stress measures were assessed at four time points at each exposure session (start, +10 min, +30 min/end, +60 min/recovery). ED and depressive psychopathology were assessed via self-rating questionnaires.

Results

A between-session habituation effect was found for subjective stress ratings and sAA levels with decreasing scores throughout the four sessions. A within-session habituation was found for cortisol levels. Higher psychopathology was associated with subjective stress ratings. There were no group differences between AN and BD regarding ED psychopathology or subjective or objective stress measures. Subjective and objective stress measures were mainly not associated with each other.

Conclusions

Habituation processes were found for subjective and objective stress, which might enhance motivation to continue BE interventions and thus increase their impact. BD seems to be a transdiagnostic phenomenon with BE as a successful intervention independent of psychiatric diagnosis. Current findings should be validated in larger samples, and the hypothesis of a transdiagnostic BD should be investigated in future research.

Psychobiological Stress Response Profiles in Current and Remitted Depression: A Person-Centered, Multisystem Approach

Background

A dysregulated stress response, including exaggerated affective reactivity and abnormal hypothalamic-pituitary-adrenal axis responsivity, has been implicated in the etiology, maintenance, and relapse of major depressive disorder (MDD). Among adolescents, discordant affective and physiological stress response profiles have been linked to negative affective outcomes and increased risk for psychopathology. Whether these findings extend to adults with varying degree of MDD risk is unclear, as are possible links to various risk factors.

Methods

We used a person-centered, multisystem approach in a sample of 119 unmedicated adults with current or remitted MDD and individuals without past MDD to evaluate psychobiological stress response profiles. Multitrajectory modeling was applied to positive affect, negative affect, and salivary cortisol (CORT) levels in response to the Maastricht Acute Stress Test.

Results

Analyses identified 4 within-person profiles, 1 typical, termed normative (n = 32, 26.9%) and 3 atypical: CORT hyperreactivity affective stability (n = 17, 14.3%), CORT hyporeactivity affective reactivity 1 (n = 45, 37.8%), and CORT hyporeactivity affective reactivity 2 (n = 25, 21.0%). While validating the assumption of a normative profile and increased risk for psychopathology in non-normative stress response profiles, coherent associations emerged between stress response profiles and clinical status, depression severity, anhedonia, perceived stress, childhood adversity, and reports of well-being, suggesting increased risk for psychopathology for individuals with a hyperreactive or discordant hyporeactive stress response profile.

Conclusions

This work advances our understanding of stress response mechanisms in MDD and underscores the potential of targeted interventions to enhance resilience and reduce psychopathology based on individual stress response profiles.

Effect of dynamic interaction of estrous cycle and stress on synaptic transmission and neuronal excitability in the lateral habenula

The prevalence of depressive disorders in women has been reported in many countries. However, the cellular mechanisms mediating such sex differences in stress susceptibility remain largely unknown. Previously, we showed that lateral habenula (LHb) neurons are more activated in female mice than in male mice by restraint stress. Given the important role of LHb in depressive disorders, we aimed to investigate the synaptic differences between male and female LHb and to examine the possible impact of the estrous cycle on neurotransmission in LHb. We found that the passive and active properties of LHb neurons differed according to the estrous cycle. Spontaneous excitatory postsynaptic currents exhibited higher amplitudes during the diestrus stage and lower frequencies in females than in males, whereas inhibitory postsynaptic currents showed no significant differences. Acute stress-induced hyperpolarization of resting membrane potentials (RMP) was observed in both sexes, with notable changes in female silent and tonic neurons. Stress exposure eliminated estrous cycle-dependent RMP differences and introduced cycle-specific excitability changes, especially in the metestrus and diestrus stages, suggesting that the hormonal cycle may set the synaptic tone of the LHb, thus modulating stress responses in females. Our study provides invaluable groundwork for understanding the detailed interaction between the estrous cycle and stress exposure in female LHb.

Shikonin ameliorates depressive- and anxiogenic-like behaviors in rats via the suppression of inflammation in the hippocampus

Shikonin is an active naphthoquinone with antioxidative, anti-inflammatory, and anticancer properties. In this study, we investigated the effects of shikonin on depressive- and anxiety-like behaviors in lipopolysaccharide- (LPS-) induced depression and chronic unpredictable mild stress (CUMS) rat models and explored the potential mechanism. First, a 14-day intraperitoneal administration of shikonin (10 mg/kg) significantly decreased immobility time in forced swimming test (FST) and increased open arm entries in elevated plus maze (EPM) test, without affecting line crossings in open field test (OFT), indicating that shikonin has anti-depressant- and anxiolytic-like effects. Second, chronic shikonin administration (10 mg/kg) reversed depressive- and anxiety-like behaviors in LPS-induced and CUMS depression models, as shown in the sucrose preference test (SPT), FST, EPM, and novel object recognition test (NORT). Finally, shikonin significantly reduced the levels of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) in hippocampus, indicating that the anti-depressant- and anxiolytic-like effects of shikonin are related to the reduction of neuroinflammation in hippocampus. These findings suggest that shikonin exerts anti-depressant- and anxiolytic-like effects via an anti-inflammatory mechanism of shikonin in the hippocampus.

Are There Biological Correlates of Response to Yoga-Based Interventions in Depression? A Critical Scoping Review

Depression is the most common mental disorder worldwide. Both antidepressants and psychotherapy are effective in treating depression, but the response to these treatments is often incomplete. Yoga-based interventions (YBIs) have been advocated by some researchers as a promising form of alternative treatment for depression. Recent research has attempted to identify the biological mechanisms associated with the antidepressant actions of YBIs. In this scoping review, conducted according to the PRISMA-ScR guidelines, the PubMed and Scopus databases were searched to retrieve research on biomarkers of response to YBIs in patients with depression. These studies were also critically reviewed to evaluate their methodological quality and any sources of bias. Nineteen studies were included in the review. Based on these studies, there is preliminary evidence that YBIs may be associated with increased serum brain-derived neurotrophic factor (BDNF) and reduced serum cortisol and interleukin-6 (IL-6) in patients with depression. However, many of these changes were also observed in the control arms, and the overall quality of the research was low. At present, it cannot be concluded that there are reliable biomarkers of response to YBIs in depression, though there are some potential biological correlates. Further advances in this field will depend critically on improvements in study design, particularly the minimization of sources of bias and the selection of more specific and sensitive biomarkers based on existing evidence from other treatment modalities.

Sex differences in body temperature and neural power spectra in response to repeated restraint stress

Repeated stress is associated with an increased risk of developing psychiatric illnesses such as post-traumatic stress disorder (PTSD), which is more common in women, yet the neurobiology behind this sex difference is unknown. Habituation to repeated stress is impaired in PTSD, and recent preclinical studies have shown that female rats do not habituate as fully as male rats to repeated stress, which leads to impairments in cognition and sleep. Further research should examine sex differences after repeated stress in other relevant measures, such as body temperature and neural activity. In this study, we analyzed core body temperature and EEG power spectra in adult male and female rats during restraint, as well as during sleep transitions following stress. We found that core body temperature of male rats habituated to repeated restraint more fully than female rats. Additionally, we found that females had a higher average beta band power than males on both days of restraint, indicating higher levels of arousal. Lastly, we observed that females had lower delta band power than males during sleep transitions on Day 1 of restraint, however, females demonstrated higher delta band power than males by Day 5 of restraint. This suggests that it may take females longer to initiate sleep recovery compared with males. These findings indicate that there are differences in the physiological and neural processes of males and females after repeated stress. Understanding the way that the stress response is regulated in both sexes can provide insight into individualized treatment for stress-related disorders.