A Comprehensive Overview on Stress Neurobiology: Basic Concepts and Clinical Implications

Beyond physical exhaustion: Understanding overtraining syndrome through the lens of molecular mechanisms and clinical manifestation

Background

Overtraining Syndrome (OTS) is a condition resulting from excessive physical activity without adequate recovery, predominantly affecting elite athletes and military personnel. While overreaching can be a temporary state, non-functional overreaching may progress to chronic OTS. This review explores various hypotheses regarding the pathogenesis of OTS, including glycogen depletion, dysregulated cytokine response, oxidative stress, and alterations in the autonomic nervous system function. It also highlights the systemic impact of OTS on multiple organ systems, immune function, and overall health, linking the condition to chronic inflammation and an increased disease susceptibility. Additionally, it addresses the role of the gut microbiome in health modulation through physical activity.

Methods

This narrative review was conducted through a structured search of peer-reviewed journal articles in databases such as PubMed, Web of Science, and Google Scholar, focusing on studies involving human participants and published in English.

Results

OTS has systemic effects on multiple organ systems, immune function, and overall health, leading to chronic inflammation and increased disease susceptibility. Athletes with OTS exhibit higher morbidity rates, influenced by factors such as sleep deprivation and stress. The review also emphasizes the role of the gut microbiome as a significant modulator of health through physical activity.

Conclusion

Balanced training and recovery are crucial for preventing OTS and maintaining optimal health and quality of life in physically active individuals. Understanding the complex pathophysiology of OTS is essential for developing effective prevention and treatment strategies.

Psychological and immunological associations with movement-evoked low back pain among older adults

Introduction

Low back pain (LBP) is a leading global factor in disability among older adults. Movement-evoked pain (MEP) is potentially an important mediator in the disability pathway but is predominantly tested in the laboratory.

Objectives

We aimed to explore MEP in the natural environment ("daily" MEP) and its correlation with laboratory MEP, along with potential psychological and immunological influences.

Method

Thirty-five older adults with persistent LBP attended a single laboratory session. Pain catastrophizing, pain-related fear of movement, and pain self-efficacy were measured by questionnaire. Resting inflammation and inflammatory reactivity to painful movement were evaluated using serum interleukin-6, tissue necrosis factor alpha, and C-reactive protein (CRP). Laboratory MEP was defined by aggregate pain intensity with a movement provocation test. Daily MEP was measured for the next 7 days using ecological momentary assessment.

Results

Laboratory MEP was strongly correlated with daily MEP (ρ = 0.780, P = <0.001). C-reactive protein (Hedges [g] = 0.266) and interleukin-6 (g = 0.433) demonstrated small to moderate reactivity to painful movement. After controlling for age and multimorbidity, pain catastrophizing and pain self-efficacy explained 24% to 37% variance in laboratory and daily MEP. Resting inflammatory markers were not associated with MEP; however, C-reactive protein reactivity to painful movement explained 19% to 25% variance in laboratory and daily MEP.

Conclusion

Preliminary indication is that laboratory and daily MEP may be proxy measures for one another, and that MEP is influenced by psychological and immunological factors. Future studies will aim to (1) validate findings among older adults with persistent LBP and (2) for clinical phenotyping, clarify complex relationships among psychological and immunological factors with disability pathway components like MEP.

Non-aversive handling in laboratory animals and its effects on depressive-like and anxiety-related behaviors: A scoping review

Stress is an adaptive response to environmental demands, but increased intensity and frequency can lead to impaired adaptive functions. Stress is considered a risk factor for Major Depressive Disorder, a multifactorial disorder that often coexists with anxiety. Picking up laboratory mice by the tail is the most common method for animal capture and may create background stress. Non-aversive handling (NAH) includes capturing the animal with the help of a tunnel or by capturing the animal with cupped hands. Given the importance of stress-induced models in the investigation of depressive-like and anxiety-related behaviors, we conducted a literature review to investigate the current knowledge on the behavioral effects of NAH in laboratory animals. While the ability of NAH to counteract depressive-like behavior has yielded mixed results, its ability to induce anxiolytic-like effects in mice has been confirmed by several studies. Some of the studies also investigated the impact of NAH on stress-related molecules (e.g. corticosterone) and physiological parameters (i.e. adrenal gland mass and body weight). The anxiolytic-like effect elicited by NAH seems to be well established in the literature, but little is known about the biochemical pathways underlying it and its antidepressant potential.

Identifying the most effective acute stress induction methods for producing SAM- and HPA-related physiological responses: a meta-analysis

BACKGROUND AND OBJECTIVES

Laboratory-based stress inductions are commonly used to elicit acute stress but vary widely in their procedures and effectiveness. We compared the effects of stress induction techniques on measures of two major biological stress systems: the early sympathetic-adrenal-medullary (SAM) and the delayed hypothalamic-pituitary-adrenal (HPA) axis response.

DESIGN

A review and meta-analysis to examine the relationship between stress induction techniques on cardiorespiratory and salivary measures of SAM and HPA system activity.

METHODS

A systematic literature search identified 245 reports and 700 effects.

RESULTS

The overall effect of stress induction techniques on the stress response was moderate (Fisher's zr = 0.44), inducing stronger SAM-related (zr = 0.48) versus HPA-related (zr = 0.37) responses. Three factors moderated these associations: the stress system examined (SAM vs HPA), the specific stress induction technique employed (e.g., Cold Pressor), the physiological sampling time relative to the stress induction, and participant sex. Loud music elicited the most robust SAM-related effects, whereas combined stress inductions elicited the most robust HPA-related effects. Men showed stronger stress responses than women.

CONCLUSIONS

Stress induction techniques variably elicit SAM - and HPA-related responses. Results recommend specific induction techniques for targeting stress systems, highlighting the importance of carefully selecting methodologies in laboratory contexts.

Quadratic associations between cardiovascular stress reactivity and development of cool and hot executive functions in adolescents

Stress affects executive functions and exploring the association between stress-induced physiological reactivity and executive functions could highlight the potential mechanism of the stress-cognitive function link. Our study examined the linear and nonlinear associations between cardiovascular stress reactivity and cool and hot executive functions among adolescents. In November 2021 (T1), 273 Chinese adolescents between 11 and 14 (Mage = 12.93, SDage = 0.79) underwent a speech task during which their cardiovascular data were recorded, and they completed a Flanker task and an Emotional Stroop task. In May 2023 (T2), 253 adolescents again completed the Flanker and Emotional Stroop tasks. Cool and hot executive functions were assessed using the intra-individual reaction time variability of the Flanker task and Emotional Stroop task, respectively. Results showed that cardiovascular stress reactivity was positively linearly associated with cool executive functions at T1 and quadratically (inverted U-shaped) associated with cool executive functions at T1 and hot executive functions at T1 and T2. These findings suggest that compared to very high and very low cardiovascular reactivity, moderate to high cardiovascular reactivity to a structured social challenge is associated with better cool and hot executive functions.

Blunted Cold Pressor-Induced Cortisol but not Total Ghrelin Response in Women with Bulimia Nervosa following a Standardized Sweet-Fat Liquid Meal

BACKGROUND

Bulimia nervosa (BN) involves recurrent episodes of uncontrolled eating followed by compensatory behaviors. Stress is implicated in BN, affecting the hypothalamic-pituitary-adrenal (HPA) axis and ghrelin, a key appetite-regulating hormone. Studies report conflicting HPA axis findings in BN, necessitating further investigation.

OBJECTIVE

To examine the impact of acute stress on cortisol and serum ghrelin and eating disorder symptoms in women with BN and healthy controls (HC).

METHODS

Participants underwent a socially evaluated cold pressor test (CPT) and control condition (quiet rest) before consuming a sweet-fat liquid meal (530 Kcal milkshake). Hormonal responses and subjective measures of stress, interoception, and appetite were assessed.

RESULTS

In BN but not HC, desire to binge remained consistently high in both conditions and correlated with perceived hunger. There were no group differences in total ghrelin levels and levels were not influenced by the CPT. Baseline cortisol levels were similar for HC and BN groups, however BN subjects did not demonstrate a CPT-induced elevation in cortisol.

CONCLUSION

HPA axis dysregulation is present in BN, and meal-related total ghrelin does not appear to be involved in the stress response in women with or without BN. Desire to binge is persistent in BN, irrespective of the presence of an acute stressor with sweet-fat meal and may be associated with heightened emotional states in general.

Deletion of Fgf14 confers resilience to basal and stress-induced depressive-like behavior and reduces anxiety in mice

Depression is a mental illness characterized by despair behavior, inability to feel pleasure, and social withdrawal. Causes are not yet clarified, but stress is a condition that induces depression. Neuronal alterations, comprising maladaptive neuronal plasticity and excitability, are present in both responses to stress and depression. Fibroblast growth factor 14 (Fgf14) controls neuronal excitability and proper action potential firing by stabilizing voltage-dependent sodium (Nav) channels into the axon. Fgf14-Nav channels complex is regulated by glycogen synthase kinase 3. Recently, Fgf14 has been genetically associated to depression. However, little is known about its role in controlling stress-induced depression. This study demonstrates that female Fgf14-/- mice are resilient to depression, as reported by reduced level of despair behavior, anhedonia, and increased sociability. Also, a reduction of anxious-like behavior was highlighted. Fgf14-/- mice showed increased expression of cannabinoid receptor without alterations of dopaminergic system in mPFC, suggesting a link between Fgf14 and endocannabinoid system in the control mechanisms underlying depression. Neuronal activity was assessed by analyzing cFOS expression during basal and following acute stress induced by tail suspension test (TST). The analysis revealed that neuronal activation in mPFC and VTA was correlated to immobility, where ratio of cFOS expression over immobility was significantly higher in Fgf14-/- mice. This suggests that higher neuronal activity might be involved in resilience to depression. In resilient Fgf14-/- mice, TST-induced acute stress caused activation only in pyramidal neurons. Our findings suggest that Fgf14 is involved in stress-coping mechanisms and could be targeted to improve resilience to depression.

Stress and gender differences in brain development

This chapter investigates the ways in which male and female brains are differently affected by stress during early development, which in turn affects how susceptible each group is to stress-related illnesses. When examining the structure and function of the brain, gender differences and stress must be taken into account. Male and female brain development differs in response to the prenatal testis's secretion of androgen. It appears that when it comes to responding to stress, encoding memories, feeling emotions, solving specific issues, and making decisions, men and women use distinct areas of the brain. Findings revealed that stress led to specific changes in brain structure and function, with gender-specific differences observed. The prefrontal cortex, the hippocampus, and the amygdala are among the brain regions connected to the stress response. The stress response has been linked to the presentation of numerous mental and psychosomatic conditions. The way men and women respond to stress varies on a biological and psychological level. To gain more insight into the gender differences seen throughout brain development, these disparities must also be investigated. This chapter implies that gender-specific vulnerabilities should be addressed and healthy brain development should be promoted by stress-related interventions.

Heat Stress and Its Impact on Corpus Luteum (CL) Function and Reproductive Efficiency in Mammals: A Critical Review

Heat stress is considered as one of the most crucial environmental stressors affecting reproductive efficiency in mammals through modulation of the function of Corpus Luteum (CL) that plays a vital role in progesterone production and pregnancy maintenance. Therefore, this detailed systematic review seeks to bring forward the interdisciplinary perspectives on the impact of heat stress exposure on CL function regarding hormonal shift, luteal phase distortion and fertility receptivity. High temperatures are shown to impose oxidative stress, change blood perfusion within the CL, signal transduction which converts the signal from the signaling molecule into an intracellular reaction and impaired luteal activity. This review incorporates various scientific studies on these effects to different mammalian species concerning the associated physiological mechanisms. Besides this, it also considers the overall impact in warm stressed population in livestock breeding in the agricultural system as well as their conservation from a general perspective. Some of the prevention and control measures for heat related reproductive problems are also covered here, addressing the importance of finding the impact on the CL in order to put in place these interventions. This review may be used to inform future developments that may improve the CL function with regards to heat stress and possible solutions to help mammals reproduced under climate change tender environment and even rising temperatures globally.

Neurophysiology of adaptative and maladaptive stress: Relations with psychology of stress

OBJECTIVES

The stress reaction is an integrated response to a change in the environment that enables each individual to adapt to demand. While this response is physiologically coordinated by the brain, its phenomenology is expressed in the field of psychology and psychopathology. This interrelation between neurophysiological mechanisms and psychological processes is complex as dynamic interpersonal, biological, and psychocognitive systems interact with contextual and environmental factors to shape adaptation over the life constraints.

METHOD

This article aims to present the actors of the adjusted stress response, such as coping and coping flexibility, mindfulness and resilience, and their respective neurophysiology.

RESULTS

A model of the relationship between resilience, mindfulness and coping was proposed for optimizing adaptation to stress response.

DISCUSSION

These focuses are prerequisites for understanding and supporting human adaptation in the everyday environment and promoting efficient management of stress for mental and physical health.

Transgenerational transmission of prenatal maternal stress across three generations of male progeny alters inflammatory stress markers in reproductive tissues

Prenatal maternal stress may lead to adverse pregnancy outcomes such as preterm birth and low birth weight. Our team has demonstrated in multiple rat models that prenatal maternal stress modifies the expression of inflammatory and stress regulators in the uterus and that this is transgenerationally passed over multiple generations through the female progeny. In this study, we investigated if male progeny exposed to ancestral prenatal maternal stress could also transmit changes to cause fetal programming of reproductive organs, leading to adverse pregnancy outcomes. We created a paternal transgenerational prenatal stress rat model. Dams (F0) were exposed to chronic variable stress during pregnancy, and their F1 male offspring stressed in utero were bred with control females for two generations. Gestational lengths and litter sizes were unchanged. Elevated gene expression of pro-inflammatory molecules in the uteri of F2 and F3 offspring was observed. Uterine expression of stress markers in the F2 and F3 females also increased even though plasma corticosterone levels were unchanged. Changes in the testicular expression of inflammatory and stress markers were also transmitted through the paternal lineage. These changes, however, tended to bear anti-inflammatory and adaptive functions, indicating compensatory mechanisms at play. These results demonstrate that fetal programming of uterine and testicular gene expression patterns can be transmitted through male progeny exposed to prenatal maternal stress.

Genetic, Epigenetic, and Hormonal Regulation of Stress Phenotypes in Major Depressive Disorder: From Maladaptation to Resilience

Major Depressive Disorder (MDD) is a complex psychiatric disorder with varied molecular mechanisms underlying its aetiology, diagnosis, and treatment. This review explores the crucial roles of stress, genetics, epigenetics, and hormones in shaping susceptibility and resilience to mood disorders. We discuss how acute stress can be beneficial, while prolonged stress disrupts brain function, leading to MDD. The review also highlights the significance of various animal models in understanding depression pathophysiology, including zebrafish, mice, and rats, which exhibit distinct sex differences in stress responses. Furthermore, we delve into the molecular bases of susceptible and resilient phenotypes, focusing on genetic aspects such as gene polymorphisms, mutations, and telomere length alterations. The review also examines epigenetic aspects including DNA methylation, histone acetylation and deacetylation, histone methylation and HMTs, and miRNA, which contribute to the development of MDD. Additionally, we explore the role of hormones such as estrogen, progesterone, and prolactin in modulating stress responses and influencing MDD susceptibility and resilience. Finally, we discuss the clinical implications of these findings, including recent clinical methods for determining MDD susceptibility and resiliency phenotypes. By consolidating the current knowledge and insights, this review aims to provide a comprehensive understanding of the molecular basis of susceptibility and resilience in mood disorders, contributing to the ongoing efforts in combating this debilitating disorder.

A Scoping Review of Studies Reporting Heart Rate Variability Measurement Among Pregnant and Postpartum People Using Wearable Technology

Maternal mental health conditions significantly contribute to pregnancy-related mortality in the United States. Approximately 20-25% of postnatal women exhibit symptoms of depressive and anxiety disorders. Mental health is influenced by stress, which affects mood, cognition, and behavior. Heart rate variability (HRV), the time interval between consecutive heartbeats, is a physiological marker for assessing stress levels, providing critical insights into the body's autonomic responses. Wearable devices measuring HRV offer a non-invasive method to monitor stress and mental health, enabling early detection of maternal stress dynamics to facilitate timely interventions. In this scoping review, we aimed to capture the current state of science on two areas of focus: (1) utilization of wearable technology for HRV monitoring in pregnant and postpartum women, (2) findings from these perinatal HRV studies, including observed HRV trends throughout pregnancy and postpartum, as well as the association between HRV, perinatal stress, and mental health. The six included perinatal HRV studies employed five fitness tracking wearables, utilizing either periodic or continuous 24-h monitoring. Findings include evidence that HRV declines during pregnancy, with a return to normal levels postpartum. Associations between HRV and stress were inconsistent across studies, with some demonstrating correlations and others reporting no relationship. Postpartum HRV measurements effectively differentiated between women with postpartum depression (PPD) versus those with adjustment disorder (AJD), demonstrating high diagnostic accuracy. In this scoping review, HRV shows promise as a stress biomarker among pregnant/postpartum people, although more work is needed to standardize optimal methods of wearable HRV measurement in this population.

Does Vagal Nerve Activity Predict Performance in a Naval Commando Selection Test?

Special operations forces (SOF) soldiers are elite fighters and tactical professionals who perform in high-stress environments. SOF selection processes aim to identify candidates who can sustain performance in high-stress and changing conditions. The vagal nerve is a crucial moderator of stress responses, and its activity (indexed by heart rate variability, HRV) has been shown to predict performance and psycho-physiological resilience in various settings. However, its predictive validity needs to be clarified. This study examined the relationship between HRV and success in an intensive selection procedure. In a historical prospective study, we derived an HRV parameter (root mean square of successive differences between normal heartbeats, RMSSD) from a 10-second ECG of 365 candidates for an SOF naval unit. The ECG was taken approximately two months before the selection procedure. The predictive validity of other routinely obtained measures was also considered. High RMSSD was significantly associated with success, but this relation disappeared after controlling for confounders (e.g., running score). However, after matching pairs of successful and non-successful candidates on confounders, HRV was again significantly related to course performance. The results of this study support the predictive value of HRV for tactical professionals. Given the high cost of training elite soldiers and the burden they undergo, improving accuracy of the selection processes may reduce the burden on candidates and lead to resource savings. Future studies should measure HRV at several time points with longer ECG records.

Frustration and its impact on search and rescue canines

Despite advances in modern technology, dogs remain the primary detection tool in search and rescue (SAR) missions, locating missing persons across diverse and dynamic environments, including wilderness, avalanche zones, water, and disaster areas. Their exceptional olfactory abilities, combined with their capacity to process complex discrimination tasks and adapt to varied environmental stimuli, make them uniquely suited for this work. However, SAR operations can be both physically and psychologically demanding, requiring sustained focus, endurance, and consistent performance under stressful conditions. Frustration, a form of psychological stress, arises when a dog encounters blocked access to a goal or when an expectation is violated, triggering physiological and behavioral changes that may impact performance. This study investigated the physiological and behavioral responses of SAR dogs to two distinct stress conditions: psychological stress induced by frustration and physiological stress induced by moderate exercise. We measured heart rate variability as an indicator of autonomic nervous system response to stress and analyzed search task performance to assess how frustration and exercise affected the dogs' latency and accuracy in executing their trained final response to the target odor. Our results revealed significant decreases in heart rate variability following frustration and increased latency in the search task, suggesting that frustration had a more pronounced impact on the dogs' physiological state and performance compared to exercise. By examining the effects of psychological and physiological stress, this study contributes to a deeper understanding of how different stressors influence SAR dog performance and welfare. These findings provide valuable insights for optimizing training methodologies and operational preparedness, ensuring both the effectiveness and well-being of SAR dogs in the field.

On the role of epigenetic modifications of HPA axis in posttraumatic stress disorder and resilience

Stress is a fundamental adaptive response that invokes amygdala and hypothalamus-pituitary-adrenal (HPA) axis along with other brain regions. Extreme or chronic stress, however, can result in a multitude of neuropsychiatric disorders, including anxiety, paranoia, bipolar disorder (BP), major depressive disorder (MDD), and posttraumatic stress disorder (PTSD). Despite widespread exposure to trauma (70.4%), the incidence of PTSD is relatively low (6.8%), suggesting that either individual susceptibility or adaptability driven by epigenetic and genetic mechanisms are likely at play. PTSD takes hold from exposure to traumatic events, such as death threats or severe abuse, with its severity being impacted by the magnitude of trauma, its frequency, and the nature. This comprehensive review examines how traumatic experiences and epigenetic modifications in hypothalamic-pituitary axis (HPA), such as DNA methylation, histone modifications, noncoding RNAs, and chromatin remodeling, are transmitted across generations, and impact genes such as FKBP prolyl isomerase 5 (FKBP5), nuclear receptor subfamily 3 group C member 1 (NR3C1), brain-derived neurotrophic factor (BDNF), and solute carrier family 6 member 4 (SLC6A4). It also provides a comprehensive overview on trauma reversal, resilience mechanisms, and pro-resilience factors such as histone acetyltransferases (HATs)/histone deacetylases (HDACs) ratio, dehydroepiandrosterone (DHEA)/cortisol ratio, testosterone levels, and neuropeptide Y, thus highlighting potential therapeutic approaches for trauma-related disorders. The studies highlighted here underscore the narrative, for the first time, that the examination and treatment of PTSD and other depressive disorders must invoke a multitude of approaches to seek out the most effective and personalized strategies. We also hope that the discussion emanating from this review will also inform government policies directed toward intergenerational trauma and PTSD.

The impact of limited sucrose intake on perineuronal nets of parvalbumin interneurons in the basolateral amygdala: A potential role in stress resilience

Natural rewards like regular sucrose consumption can buffer physiological and behavioral stress responses, likely mediated, at least in part, by increased plasticity in parvalbumin-positive (PV+) interneurons in the basolateral amygdala (BLA). As PV+ interneuron plasticity is tightly regulated by specialized extracellular matrix structures called perineuronal nets (PNNs), this study investigated the impact of regular sucrose consumption vs. repetitive stress on the PNNs that surround PV+ interneurons in the BLA, as well as the number of glutamatergic (vGLUT1) and GABAergic (vGAT) appositions that PV+ cells receive. Male rats were given an established limited sucrose intake (LSI) feeding paradigm (vs. water-fed controls) and were co-exposed to a brief restraint stress (vs. no stress controls), daily for 14 days. Sucrose consumption increased the proportion of PV+ cells that were surrounded by PNNs, independent of stress exposure. PV+ cells with PNNs had more vGLUT1-positive and fewer vGAT-positive appositions compared to those lacking PNNs. Additionally, sucrose consumption increased the ratio of excitatory/inhibitory appositions onto PV+ cells, suggesting the possibility of elevated PV+ interneuron tone, leading to greater inhibition of the BLA's stress-excitatory output. These findings indicate that sucrose consumption influences PNN formation and structural plasticity on PV+ interneurons in the BLA, which has implications for understanding the neurological mechanisms underlying stress resilience by natural rewards.

From Discrimination to Disease: The Role of Inflammation

ABSTRACT

Discrimination is an established social determinant of mental health that contributes to psychiatric illness disparities among marginalized populations. There is emerging research elucidating the biological mechanisms connecting discrimination to mental health outcomes, revealing inflammation as a key pathway. This column synthesizes evidence from existing literature on the links between discrimination and inflammation, and outlines both the opportunities and challenges in this field. The discussion highlights the necessity of a multifaceted approach to address discrimination, and thus, reduce inflammation at both individual and population levels.

Circulating Stress Hormones, Brain Health, and Cognition in Healthy Older Adults: Cross-Sectional Findings and Sex Differences in Age-Well

Background

Increased stress is a proposed risk factor for Alzheimer's disease (AD). We examined cross-sectional associations between circulating stress biomarkers and multimodal measures of brain health and cognition susceptible to AD in older adults and sex-specific subgroups.

Methods

Baseline data from 132 cognitively unimpaired participants without depression (age, mean ± SD = 74.0 ± 4.0 years, women: n = 80) in the Age-Well trial (NCT02977819) were included. Stress hormone levels were measured in overnight fasting blood serum (cortisol, dehydroepiandrosterone sulfate) and blood plasma (epinephrine, norepinephrine) samples. AD-sensitive measures of brain health, including glucose metabolism (n = 89), cerebral perfusion, gray matter volume, amyloid deposition in a priori regions of interest, and cognitive markers were evaluated. Models were adjusted for age, sex, education, trait anxiety, and depressive symptoms.

Results

Higher epinephrine levels were associated (false discovery rate-corrected p < .05) with lower glucose metabolism in the anterior cingulate cortex (β = -0.26, p = .008), posterior cingulate cortex (β = -0.32, p = .006), and precuneus (β = -0.27, p = .021) and lower perfusion in the posterior cingulate cortex (β = -0.23, p = .013). Interactions between stress hormones and sex showed (false discovery rate-corrected p < .05) that in women only, higher epinephrine was associated with larger anterior cingulate cortex volume (interaction: β = 0.32, p = .016), whereas in men only, higher cortisol was associated with lower episodic memory performance (interaction: β = 0.98, p = .012).

Conclusions

The current study demonstrates the involvement of circulating stress hormones, particularly epinephrine and cortisol, in greater resilience or vulnerability of brain health and cognitive indicators of susceptibility to AD in older adults. The identification of sex-specific patterns in these associations may inform the development of more effective and tailored interventions.

I "Gut" Rhythm: the microbiota as a modulator of the stress response and circadian rhythms

Modern habits are becoming more and more disruptive to health. As our days are often filled with circadian disruption and stress exposures, we need to understand how our responses to these external stimuli are shaped and how their mediators can be targeted to promote health. A growing body of research demonstrates the role of the gut microbiota in influencing brain function and behavior. The stress response and circadian rhythms, which are essential to maintaining appropriate responses to the environment, are known to be impacted by the gut microbiota. Gut microbes have been shown to alter the host's response to stress and modulate circadian rhythmicity. Although studies demonstrated strong links between the gut microbiota, circadian rhythms and the stress response, such studies were conducted in an independent manner not conducive to understanding the interface between these factors. Due to the interconnected nature of the stress response and circadian rhythms, in this review we explore how the gut microbiota may play a role in regulating the integration of stress and circadian signals in mammals and the consequences for brain health and disease.

Obsessive‒compulsive symptoms and associated factors among people with schizophrenia attending services at referral hospitals in Eastern Ethiopia

BACKGROUND

Obsessive-compulsive symptoms are mental health conditions marked by the presence of obsessions and/or compulsions. Even though significant portion people with schizophrenia are reportedly affected by obsessive-compulsive symptoms, there is scarce of information related to this topic in Africa, and particularly in study area.

OBJECTIVE

This study aimed to assess the magnitude and associated factors of obsessive‒compulsive symptoms among people with schizophrenia attending services at referral hospitals in Eastern Ethiopia from February 15 to March 15, 2024.

METHODS

An institutional-based, cross-sectional study was conducted among adults with schizophrenia. Systematic sampling was used to select 422 study participants. The Yale-Brown Obsessive-Compulsive Scale was used to assess obsessive-compulsive symptoms. Data entry and analysis were performed by EpiData 4.6 and STATA 14, respectively. Bivariable and multivariable logistic regression were performed, and variables with p values < 0.05 were considered statistically significant.

RESULTS

The proportion with obsessive‒compulsive symptoms in this study was 44.07% (95% CI, 39.33%-48.92%). After adjusting for possible confounders, duration of schizophrenia from 3-4 years (AOR = 3.41; 95% CI, 1.28-9.05), duration of schizophrenia 5 years and above (AOR = 6.08; 95% CI, 2.26-16.31), current use of alcohol (AOR = 2.12; 95% CI, 1.09-4.12), current use of khat (AOR = 6.09; 95% CI, 3.15-11.74), being a probable case of anxiety (AOR = 3.57; 95% CI, 1.95-6.53), being a probable case of depression (AOR = 4.56; 95% CI, 2.39-8.66), being on Risperidone (AOR = 5.08; 95% CI, 2.52-10.23) and being on Olanzapine (AOR = 5.95; 95% CI, 2.72-13.04) were significantly associated with obsessive‒compulsive symptoms. CONCLUSIONS AND RECOMMENDATION: The prevalence of obsessive‒compulsive symptoms was relatively high. Timely detection and appropriate interventions are crucial and special consideration is better to be given for those with comorbid substance use, comorbid anxiety and depression, as well as those taking second-generation antipsychotics.

Neuronal stress-coping mechanisms in postpartum females

Animals exhibit a wide range of stress responses aimed at restoring homeostasis and promoting adaptation. In response to stress, they employ coping mechanisms to maintain physiological balance. Dysregulated stress-coping strategies have been associated with mental disorders, including depression, anxiety, and post-traumatic stress disorder. Understanding the neuronal mechanisms that regulate stress-coping is critical for elucidating normal physiological responses and addressing the pathological processes underlying these disorders. Stress responses are influenced by sex and life stage, with notable variability in the prevalence and severity of mental disorders based on these factors. Stress-coping mechanisms are pivotal in determining the vulnerability or resilience of an individual to stress. Thus, identifying differences in stress-coping strategies between sexes and across life stages is essential for advancing prevention and treatment strategies for stress-related mental disorders. This review explores the neuronal mechanisms underlying stress responses, emphasizing the distinct stress-coping strategies utilized by postpartum females. Highlighting these differences underscores the need for targeted prevention and treatment approaches that consider sex- and life stage-specific variations in stress-coping mechanisms.

Molecular mechanism underlying stress response and adaptation

Stress, a common life experience, impacts both mental and physical health, contributing to conditions such as anxiety and cardiovascular disease. It triggers physiological and psychological responses, primarily through the Hypothalamic-Pituitary-Adrenal (HPA) and Sympathetic-Adrenal-Medullary (SAM) axes, which are coordinated by the autonomic nervous system. Dysregulation of the glucocorticoid system, mediated by mineralocorticoid and glucocorticoid receptors, plays a critical role in neurodegenerative disorders like Alzheimer's disease. Cellular pathways like PI3K/Akt, NF-κB, and AP-1 transcription factors maintain homeostasis during stress and are targets for therapeutic research. Epigenetic influences and genomic modifications highlight the long-lasting effects of stress on gene expression. Adaptive responses, such as allostasis, allow the body to maintain stability amid stress. However, excessive stress leads to allostatic load, negatively impacting the immune, endocrine, and nervous systems. Current treatments include pharmacological and lifestyle interventions, with emerging approaches such as psychobiotics and precision medicine offering future potential.

Architecturally Mediated Allostasis and Neurosustainability: A Proposed Theoretical Framework for the Impact of the Built Environment on Neurocognitive Health

The global rise in mental health-related disorders represents a significant health and wellbeing challenge, imposing a substantial social and economic burden on individuals, communities, and healthcare systems. According to the World Health Organization, one in four people globally will be affected by mental or neurological disorders at some point in their lives, highlighting a significant global health concern that warrants carefully considered and innovative responses. While mental health challenges arise from complex, multifaceted factors, emerging research indicates that the built environment-the architecture of our homes, workplaces, and public spaces-may exert a critical but underappreciated influence on mental health outcomes. This paper outlines a novel theoretical framework for how visual stressors in the built environment might trigger neurophysiological stress responses via the HPA and SAM axes, potentially contributing over time to allostatic load. In this paper, it is proposed that chronic physiological strain can alter neuroplastic processes and neurogenesis in key brain regions-such as the hippocampus, prefrontal cortex (PFC), anterior cingulate cortex (ACC), and amygdala-thereby affecting cognitive health, emotional regulation, and overall mental wellbeing. Drawing on the principle of neurosustainability, this paper suggests that long-term exposure to stress-inducing environments may create feedback loops, particularly involving the amygdala, that have downstream effects on other brain areas and may be linked to adverse mental health outcomes such as depression. By presenting this framework, this paper aims to inspire further inquiry and applied experimental research into the intersection of neurophysiology, mental health, and the built environment, with a particular emphasis on rigorous testing and validation of the proposed mechanisms, that may then be translated into practical architectural design strategies for supporting health and wellbeing. In doing so, it is hoped that this work may contribute to a more holistic approach to improving mental health that integrates the creation of nurturing, resilient spaces into the broader public health agenda.

Chronic Stress and Headaches: The Role of the HPA Axis and Autonomic Nervous System

Chronic stress significantly influences the pathogenesis of headache disorders, affecting millions worldwide. This review explores the intricate relationship between stress and headaches, focusing on the dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS). Persistent stress could lead to neuroinflammation, increased pain sensitivity, and vascular changes that could contribute to headache development and progression. The bidirectional nature of this relationship creates a vicious cycle, with recurrent headaches becoming a source of additional stress. Dysregulation of the HPA axis and ANS imbalance could amplify susceptibility to headaches, intensifying their frequency and severity. While pharmacological interventions remain common, non-pharmacological approaches targeting stress reduction, such as cognitive-behavioral therapy, biofeedback, and relaxation techniques, offer promising avenues for comprehensive headache management. By addressing the underlying stress-related mechanisms, these approaches provide a sustainable strategy to reduce headache frequency and improve patients' quality of life.

Climate-smart livestock nutrition in semi-arid Southern African agricultural systems

Climate change is disrupting the semi-arid agricultural systems in Southern Africa, where livestock is crucial to food security and livelihoods. This review evaluates the bioenergetic and agroecological scope for climate-adaptive livestock nutrition in the region. An analysis of the literature on climate change implications on livestock nutrition and thermal welfare in the regional agroecological context was conducted. The information gathered was systematically synthesized into tabular summaries of the fundamentals of climate-smart bioenergetics, thermoregulation, livestock heat stress defence mechanisms, the thermo-bioactive feed components, and potentially climate-smart feed resources in the region. The analysis supports the adoption of climate-smart livestock nutrition when conceptualized as precision feeding combined with dietary strategies that enhance thermal resilience in livestock, and the adaptation of production systems to the decline in availability of conventional feedstuffs by incorporating climate-smart alternatives. The keystone potential climate-smart alternative feedstuffs are identified to be the small cereal grains, such as sorghum (Sorghum bicolor) and pearl millet (Pennisetum glaucum) as dietary energy sources, the native legumes, such as the cowpea (Vigna unguiculata) and the marama bean (Tylosema esculentum) as protein sources, wild browse Fabaceae trees such as Vachellia spp. and Colophospermum mopane, which provide dry season and drought supplementary protein, minerals, and antioxidants, the non-fabaceous tree species such as the marula tree (Sclerocarya birrea), from which animals consume the energy and electrolyte-rich fresh fruit or processed pulp. Feedstuffs for potential circular feeding systems include the oilseed cakes from the macadamia (Macadamia integrifolia) nut, the castor (Ricinus communis), and Jatropha (Jatropha curcas) beans, which are rich in protein and energy, insect feed protein and energy, primarily the black soldier fly larvae (Hermetia illucens), and microbial protein from phototrophic algae (Spirulina, Chlorella), and yeasts (Saccharomyces cerevisiae). Additives for thermo-functionally enhanced diets include synthetic and natural anti-oxidants, phytogenics, biotic agents (prebiotics, probiotics, synbiotics, postbiotics), and electrolytes. The review presents a conceptual framework for climate-smart feeding strategies that enhance system resilience across the livestock-energy-water-food nexus, to inform broader, in-depth research, promote climate-smart farm practices and support governmental policies which are tailored to the agroecology of the region.

Stress-induced neurodegeneration and behavioral alterations in Caenorhabditis elegans: Insights into the evolutionary conservation of stress-related pathways and implications for human health

Stress is a significant determinant for a range of neurological and psychiatric illnesses, and comprehending its influence on the brain is vital for developing effective interventions. Caenorhabditis elegans (C. elegans), a tiny nematode, has become a potent model system for investigating the impact of stress on neuronal integrity, behavior, and lifespan. This chapter presents a comprehensive summary of the existing understanding of stress-induced neurodegeneration, behavioral abnormalities, and changes in lifespan in C. elegans. We explored the stress response pathways in C. elegans, specifically focusing on the heat shock response and insulin-like signaling (ILS) pathway, targeting how these pathways affect neural integrity and functions. Additionally, this chapter highlighted behavioral modifications such as changes in locomotion, feeding, pharyngeal pumping, defecation, and copulation behaviors that occur in C. elegans following exposure to stressors, and how these findings contribute to our comprehension of stress-related illnesses. Furthermore, the evolutionary preservation of stress responses in both C. elegans and humans, underscoring the significance of C. elegans studies for translational research were highlighted. In conclusion, the possible implications of C. elegans research on human well-being, with a specific emphasis on the discovery of targets for treatment and the creation of innovative approaches to address stress-related conditions are discussed in this chapter.

Introduction to neurobiology and pharmacology of stress

In order to improve individual and community health outcomes, stress research is crucial for developing our understanding of human biology, psychology, and social dynamics. It also informs therapeutic practices, public health campaigns, and educational activities. The chapter explores how neurotransmitters, including glutamate, GABA, adrenaline, norepinephrine, serotonin, dopamine, and adrenaline, mediate stress responses, impact mood and behavior, and play a part in a number of stress-related disorders. The relevance of focused research and therapy approaches aimed at reestablishing equilibrium within these systems is highlighted by the fact that dysregulation of these neurotransmitters can exacerbate health problems. Additionally, it is investigated how the amygdala, hippocampus, and prefrontal cortex interact to process emotions, build resilience, and determine an individual's susceptibility to stress. These interactions are regulated by both neuroplasticity and hereditary and epigenetic factors. The chapter discusses the pharmaceutical approach to stress management, which includes a variety of drugs such as beta-blockers, anxiolytics, and antidepressants that work by targeting different neurotransmitter systems to reduce anxiety and mood disorders. Even while these therapies work, they may have negative consequences and side effects that should be carefully considered in clinical settings. The chapter promotes a comprehensive approach to stress management that combines medication, lifestyle changes, psychotherapy, and stress-reduction methods. Healthcare workers can improve patient care and ultimately the health and quality of life for people with stress-related disorders by knowing the complexity of pharmaceutical therapies and how they affect the stress response.

Current Strategies and Future Directions of Wearable Biosensors for Measuring Stress Biochemical Markers for Neuropsychiatric Applications

Most wearable biosensors aimed at capturing psychological state target stress biomarkers in the form of physical symptoms that can correlate with dysfunction in the central nervous system (CNS). However, such markers lack the specificity needed for diagnostic or preventative applications. Wearable biochemical sensors (WBSs) have the potential to fill this gap, however, the technology is still in its infancy. Most WBSs proposed thus far target cortisol. Although cortisol detection is demonstrated as a viable method for approximating the extent and severity of psychological stress, the hormone also lacks specificity. Multiplex WBSs that simultaneously target cortisol alongside other viable stress-related biochemical markers (SBMs) can prove to be indispensable for understanding how psychological stress contributes to the pathophysiology of neuropsychiatric illnesses (NPIs) and, thus, lead to the discovery of new biomarkers and more objective clinical tools. However, none target more than one SBM implicated in NPIs. Till this review, cortisol's connection to dysfunctions in the CNS, to other SBMs, and their implication in various NPIs has not been discussed in the context of developing WBS technology. As such, this review is meant to inform the biosensing and neuropsychiatric communities of viable future directions and possible challenges for WBS technology for neuropsychiatric applications.

Physicochemical and microbiological characteristics of pork meat exposed to SoRegen® Technology

Background and Aim

Quantum entanglement has been explored as a novel approach in food technology to enhance the quality and nutritional properties of animal products. SoRegen® Technology applies quantum entanglement signals to food products, aiming to induce physicochemical modifications. This study investigates the effects of SoRegen® Technology on the physicochemical and microbiological characteristics of pork meat, focusing on meat quality attributes and cholesterol levels.

Materials and Methods

Pork meat samples were exposed to a quantum entanglement signal from a SoRegen® chip for 20 min in an electromagnetic field chamber. Physicochemical properties, including water-holding capacity (WHC), pH, drip loss, and cooking loss, were analyzed. Cholesterol levels, including total cholesterol and high-density lipoprotein (HDL) cholesterol, were measured using enzyme-linked immunosorbent assay kits. Microbiological analysis included total plate count (TPC), Escherichia coli, and Listeria monocytogenes enumeration. Data were statistically analyzed using an independent sample t-test with significance set at p < 0.05.

Results

Pork meat exposed to SoRegen® Technology exhibited significant improvements in physicochemical properties. WHC increased, indicating better moisture retention, while drip loss and cooking loss were reduced, suggesting improved meat texture and quality. Minor but statistically significant fluctuations in pH were observed at specific time points. Cholesterol analysis revealed a significant 35% reduction in total cholesterol levels, alongside a significant increase in HDL cholesterol levels, indicating potential health benefits. Microbiological analysis indicated no significant differences between exposed and unexposed pork samples in terms of E. coli, L. monocytogenes, and TPC, suggesting that the technology does not directly affect microbial contamination.

Conclusion

The application of SoRegen® Technology significantly improved the physicochemical and nutritional attributes of pork meat, particularly by enhancing WHC and reducing cholesterol levels. However, no significant changes were observed in microbiological characteristics. These findings highlight the potential of quantum entanglement technology in food science, though further research is required to elucidate the mechanisms underlying these effects and explore commercial applications.

Behavioral, metabolic, and biochemical alterations caused by an acute stress event in a zebrafish larvae model

Animal welfare is a growing concern in aquaculture practices. Stress induced by handling or transportation can lead to negative impacts on the sector. Zebrafish has raised as an important aquaculture model, but still with few focus on its stress response in early life stages. Therefore, the objective of this study was to improve the evaluation of different markers of the stress response after a stress event in a zebrafish larvae model. Zebrafish larvae (96 hpf) were vortex-stimulated for 1 min at 200 rpm for acute stress induction. After 10 min, 1- and 4-h behavioral larvae outcomes and larvae were sampled to the following quantification: levels of cortisol, lactate, glucose and biochemical biomarkers (reactive oxygen species, superoxide dismutase, catalase, glutathione peroxidase, lipidic oxidation level and protein carbonylation, glutathione s-transferase, acetylcholinesterase, lactate dehydrogenase and ATPase), and the metabolic rate. The cortisol, glucose, and lactate levels had no alterations. At the behavioral level, an increase in the distance swam and in the speed was observed and the metabolic rate also increased according to the behavioral outcomes. The ATPase and GST activity showed a decrease in their activity, probably through osmoregulation changes related to the hypothetic adrenocorticotropic hormone downregulation. Overall, the acute vortex stimulation at low speed induced an early stress response independent of the HPI-cortisol pathway. In addition, this study shows zebrafish early life stages as a sensitive model to acute vortex stimulation, identifying altered parameters which can be used in future work to assess the effect on animal welfare in similar acute situations.

Exploring the complex relationship between psychosocial stress and the gut microbiome: implications for inflammation and immune modulation

There is growing interest in understanding the complex relationship between psychosocial stress and the human gastrointestinal microbiome (GIM). This review explores the potential physiological pathways connecting these two and how they contribute to a proinflammatory environment that can lead to the development and progression of the disease. Exposure to psychosocial stress triggers the activation of the sympathetic nervous system (SNS) and hypothalamic-pituitary axis (HPA), leading to various physiological responses essential for survival and coping with the stressor. However, chronic stress in susceptible individuals could cause sustained activation of HPA and SNS, leading to immune dysregulation consisting of redistribution of natural killer (NK) cells in the bloodstream, decreased function of T and B cells, and elevation of proinflammatory cytokines such as interleukin-1, interleukin-6, tumor necrotic factor-α, interferon-gamma. It also leads to disruption of the GIM composition and increased intestinal barrier permeability, contributing to GIM dysbiosis. The GIM dysbiosis and elevated cytokines can lead to reciprocal effects and further stimulate the HPA and SNS, creating a positive feedback loop that results in a proinflammatory state underlying the pathogenesis and progression of stress-associated cardiovascular, gastrointestinal, autoimmune, and psychiatric disorders. Understanding these relationships is critical for developing new strategies for managing stress-related health disorders.

The Role of Chronic Stress in the Pathogenesis of Ischemic Heart Disease in Women

Psychological stress has emerged as a critical risk factor for cardiovascular disease, especially in women. While female participation in clinical research has improved, sex-specific data analysis and reporting often remain inadequate, limiting our ability to draw definitive conclusions for women. Conversely, preclinical studies consistently demonstrate adverse effects of stress on female health, yet the molecular mechanisms underlying this association remain elusive. Evidence suggests that female IHD pathogenesis is more complex than in males, involving multiple factors, including inflammation, contractile dysfunction, bioenergetic impairment, and remodeling. However, many of these mechanisms are primarily derived from male studies, and molecular investigations in female models are limited, hindering our understanding of the underlying biological pathways. This is particularly concerning given the increasing prevalence of ischemic heart disease in postmenopausal women. In order to fully elucidate the impact of stress on female cardiac health and develop targeted interventions, further preclinical research on female models is essential.

Mushrooms, Microdosing, and Mental Illness: The Effect of Psilocybin on Neurotransmitters, Neuroinflammation, and Neuroplasticity

The incidence of mental health disorders is increasing worldwide. While there are multiple factors contributing to this problem, neuroinflammation underlies a significant subset of psychiatric conditions, particularly major depressive and anxiety disorders. Anti-inflammatory interventions have demonstrated benefit in these conditions. Psilocin, the active ingredient of mushrooms in the Psilocybe genus, is both a potent serotonin agonist and anti-inflammatory agent, increases neuroplasticity, and decreases overactivity in the default mode network. Studies using hallucinogenic doses of psilocin under the supervision of a therapist/guide have consistently demonstrated benefits to individuals with depression and end-of-life anxiety. Microdosing psilocybin in sub-hallucinogenic doses has also demonstrated benefit in mood disorders, and may offer a safe, less expensive, and more available alternative to full doses of psilocybin for mood disorders, as well as for other medical conditions in which inflammation is the principal pathophysiology.

Pituitary adenylyl cyclase-activating polypeptide modulates the stress response: the involvement of different brain areas and microglia

Stress is necessary for survival. However, chronic unnecessary stress exposure leads to cardiovascular, gastrointestinal and neuropsychiatric disorders. Thus, understanding the mechanisms involved in the initiation and maintenance of the stress response is essential since it may reveal the underpinning pathophysiology of these disorders and may aid in the development of medication to treat stress-mediated diseases. Pituitary adenylyl cyclase activating polypeptide (PACAP) and its receptors (PAC1, VPAC1 and VPAC2) are expressed in the hypothalamus and other brain areas as well as in the adrenal gland. Previous research has shown that this peptide/receptor system serves as a modulator of the stress response. In addition to modulating the stress response, this system may also be connected to its emerging role as neuroprotective against hypoxia, ischemia, and neurodegeneration. This article aims to review the literature regarding the role of PACAP and its receptors in the stress response, the involvement of different brain regions and microglia in PACAP-mediated modulation of the stress response, and the long-term adaptation to stress recognizable clinically as survival with resilience while manifested in anxiety, depression and other neurobehavioral disorders.

Stress regulatory hormones and cancer: the contribution of epinephrine and cancer therapeutic value of beta blockers

The word "cancer" evokes myriad emotions, ranging from fear and despair to hope and determination. Cancer is aptly defined as a complex and multifaceted group of diseases that has unapologetically led to the loss of countless lives and affected innumerable families across the globe. The battle with cancer is not only a physical battle, but also an emotional, as well as a psychological skirmish for patients and for their loved ones. Cancer has been a part of our history, stories, and lives for centuries and has challenged the ingenuity of health and medical science, and the resilience of the human spirit. From the early days of surgery and radiation therapy to cutting-edge developments in chemotherapeutic agents, immunotherapy, and targeted treatments, the medical field continues to make significant headway in the fight against cancer. However, even after all these advancements, cancer is still among the leading cause of death globally. This urges us to understand the central hallmarks of neoplastic cells to identify novel molecular targets for the development of promising therapeutic approaches. Growing research suggests that stress mediators, including epinephrine, play a critical role in the development and progression of cancer by inducing neoplastic features through activating adrenergic receptors, particularly β-adrenoreceptors. Further, our experimental data has also shown that epinephrine mediates the growth of T-cell lymphoma by inducing proliferation, glycolysis, and apoptosis evasion via altering the expression levels of key regulators of these vital cellular processes. The beauty of receptor-based therapy lies in its precision and higher therapeutic value. Interestingly, the enhanced expression of β-adrenergic receptors (ADRBs), namely ADRB2 (β2-adrenoreceptor) and ADRB3 (β3-adrenoreceptor) has been noted in many cancers, such as breast, colon, gastric, pancreatic, and prostate and has been reported to play a pivotal role in facilitating cancer growth mainly by promoting proliferation, evasion of apoptosis, angiogenesis, invasion and metastasis, and chemoresistance. The present review article is an attempt to summarize the available findings which indicate a distinct relationship between stress hormones and cancer, with a special emphasis on epinephrine, considered as a key stress regulatory molecule. This article also discusses the possibility of using beta-blockers for cancer therapy.

Improving brain health via the central executive network

Cognitive and physical stress have significant effects on brain health, particularly through their influence on the central executive network (CEN). The CEN, which includes regions such as the dorsolateral prefrontal cortex, anterior cingulate cortex and inferior parietal lobe, is central to managing the demands of cognitively challenging motor tasks. Acute stress can temporarily reduce connectivity within the CEN, leading to impaired cognitive function and emotional states. However a rebound in these states often follows, driven by motivational signals through the mesocortical and mesolimbic pathways, which help sustain inhibitory control and task execution. Chronic exposure to physical and cognitive challenges leads to long-term improvements in CEN functionality. These changes are supported by neurochemical, structural and systemic adaptations, including mechanisms of tissue crosstalk. Myokines, adipokines, anti-inflammatory cytokines and gut-derived metabolites contribute to a biochemical environment that enhances neuroplasticity, reduces neuroinflammation and supports neurotransmitters such as serotonin and dopamine. These processes strengthen CEN connectivity, improve self-regulation and enable individuals to adopt and sustain health-optimizing behaviours. Long-term physical activity not only enhances inhibitory control but also reduces the risk of age-related cognitive decline and neurodegenerative diseases. This review highlights the role of progressive physical stress through exercise as a practical approach to strengthening the CEN and promoting brain health, offering a strategy to improve cognitive resilience and emotional well-being across the lifespan.

Influence of Functional Variations in Genes of Neurotrophins and Neurotransmitter Systems on the Development of Retinopathy of Prematurity

Retinal neurodevelopment, vascularization, homeostasis, and stress response are influenced by factors such as nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), tyrosine hydroxylase (TH), and erythropoietin (EPO). As retinopathy of prematurity (ROP) is a neurovascular retinal disease, this study analyzed the contributions of NGF (rs6330), BDNF (rs7934165), TH (rs10770141), and EPO (rs507392) genetic functional polymorphisms to the modulation of hematological and biochemical parameters of the first week of life and their association with ROP development. A multicenter cohort of 396 preterm infants (gestational age < 32 weeks or birth weight < 1500 g) was genotyped using MicroChip DNA and iPlex MassARRAY® platform. Multivariate regression followed univariate assessment of ROP risk factors. NGF (GG) genotype was associated with a higher ROP risk (OR = 1.79), which increased further (OR = 2.38) when epistatic interactions with TH (allele C) and BDNF (allele G) were present. Significant circulating biomarker differences, including bilirubin, erythrocytes, monocytes, neutrophils, lymphocytes, and platelet markers, were found between ROP and non-ROP groups, with variations depending on the polymorphism. These findings suggest that NGF (rs6330) and its interactions with related genes contribute to ROP risk, providing valuable insights into the genetic and biological mechanisms underlying the disease and identifying potential predictive biomarkers.

Concussion and the Autonomic, Immune, and Endocrine Systems: An Introduction to the Field and a Treatment Framework for Persisting Symptoms

A significant proportion of patients who sustain a concussion/mild traumatic brain injury endorse persisting, lingering symptoms. The symptoms associated with concussion are nonspecific, and many other medical conditions present with similar symptoms. Medical conditions that overlap symptomatically with concussion include anxiety, depression, insomnia, chronic pain, chronic fatigue, fibromyalgia, and cervical strain injuries. One of the factors that may account for these similarities is that these conditions all present with disturbances in the optimal functioning of the autonomic nervous system and its intricate interactions with the endocrine system and immune system-the three primary regulatory systems in the body. When clinicians are working with patients presenting with persisting symptoms after concussion, evidence-based treatment options drawn from the literature are limited. We present a framework for the assessment and treatment of persisting symptoms following concussion based on the available evidence (treatment trials), neuroanatomical principles (research into the physiology of concussion), and clinical judgment. We review the research supporting the premise that behavioral interventions designed to stabilize and optimize regulatory systems in the body following injury have the potential to reduce symptoms and improve functioning in patients. Foundational concussion rehabilitation strategies in the areas of sleep stabilization, fatigue management, physical exercise, nutrition, relaxation protocols, and behavioral activation are outlined along with practical strategies for implementing intervention modules with patients.

Prophylactic effects of Tibetan goat kefir on depression-like behaviors in chronic unpredictable stress model through the gut-brain axis

BACKGROUND

Depression is a common psychological disorder, and traditional therapeutic drugs often result in side effects such as emesis, dry mouth, headache, dysentery and constipation. Probiotics and goat milk have garnered widespread attention for their ability to modulate immune function and regulate the endocrine system, and for their anti-inflammatory effects. In this work, the effects of Tibetan goat kefir on the behavior, immune status, neuroendocrine response and gut microbiological composition of chronic unpredictable mild stress (CUMS) mouse models were evaluated.

RESULTS

The results indicated that Tibetan kefir goat milk significantly alleviated behavioral despair in mice. Furthermore, the results demonstrated that Tibetan kefir goat milk mitigated the inflammatory response in the mice and moderated the hyperactivity of the hypothalamic-pituitary-adrenal axis and the expression of brain-derived neurotrophic factor. Meanwhile, chronic stress-induced gut microbial abnormalities were restored. In addition, the correlation between gut microbiota and nervous system was evaluated.

CONCLUSION

These results explained the potential mechanism of Tibetan kefir in the antidepressant effect on the CUMS model and enriched diets for depressed patients. © 2024 Society of Chemical Industry.

Differential effects of chronic unpredictable stress on behavioral and molecular (cortisol and microglia-related neurotranscriptomic) responses in adult leopard (leo) zebrafish

Stress plays a key role in mental, neurological, endocrine, and immune disorders. The zebrafish (Danio rerio) is rapidly gaining popularity as s model organism in stress physiology and neuroscience research. Although the leopard (leo) fish are a common outbred zebrafish strain, their behavioral phenotypes and stress responses remain poorly characterized. Here, we examined the effects of a 5-week chronic unpredictable stress (CUS) exposure on adult leo zebrafish behavior, cortisol levels, and brain gene expression. Compared to their unstressed control leo counterparts, CUS-exposed fish showed paradoxically lower anxiety-like, but higher whole-body cortisol levels and altered expression of multiple pro- and anti-inflammatory brain genes. Taken together, these findings suggest that behavioral and physiological (endocrine and genomic) responses to CUS do differ across zebrafish strains. These findings add further complexity to systemic effects of chronic stress in vivo and also underscore the importance of considering the genetic background of zebrafish in stress research.

Early psilocybin intervention alleviates behavioral despair and cognitive impairment in stressed Wistar rats

Chronic stress exerts profound effects on mental health, contributing to disorders such as depression, anxiety, and cognitive impairment. This study examines the potential of psilocybin to alleviate behavioral despair and cognitive deficits in a rodent model of chronic stress, focusing on the interplay between the Hypothalamic-Pituitary-Adrenal (HPA) axis and the Endocannabinoid System (ECS). Twenty-two male Wistar rats were divided into control and stress groups. Animals within the stress group were exposed to predator odor and chronic social instability to induce chronic stress, and were either sham treated, or given psilocybin. Behavioral assessments were conducted using the Open Field Test, Sucrose Preference Test, Novel Object Recognition, Elevated Plus Maze, and Forced Swimming Test to evaluate locomotion, anhedonia, memory, anxiety, and behavioral despair, respectively. Blood and brain samples were analyzed for biochemical markers. Results indicated that psilocybin significantly reduced stress-induced behavioral despair and cognitive impairments, likely through ECS-mediated downregulation of the HPA axis. These findings suggest that early intervention with psilocybin has sustained beneficial effects on stress-related behavioral and cognitive disturbances, underscoring its potential as a novel therapeutic approach for stress-related mental health disorders.

Allopregnanolone and intrusive memories: A potential therapeutic target for PTSD treatment?

Significant amounts of research have been devoted to treatment of post-traumatic stress disorder (PTSD) and the understanding of its fear and stress-related symptoms. However, current interventions are only effective in 60 % of the patient population. Allopregnanolone has become a topic of interest for PTSD due to its influences on inhibitory neurotransmission and the physiological stress response. This review explores available literature that suggests that allopregnanolone has an influence on (a) chronic stress and anxiety-like symptoms, (b) fear conditioning and contextual fear, and (c) intrusive and emotional memories. A relationship between allopregnanolone and PTSD is suggested, postulating that allopregnanolone is a potential target for the treatment of PTSD. This very exciting prospect calls for the expansion of research investigating a direct relationship between allopregnanolone and PTSD.

Gut microbiota regulates stress responsivity via the circadian system

Stress and circadian systems are interconnected through the hypothalamic-pituitary-adrenal (HPA) axis to maintain responses to external stimuli. Yet, the mechanisms of how such signals are orchestrated remain unknown. Here, we uncover the gut microbiota as a regulator of HPA-axis rhythmicity. Microbial depletion disturbs the brain transcriptome and metabolome in stress-responding pathways in the hippocampus and amygdala across the day. This is coupled with a dysregulation of the circadian pacemaker in the brain that results in perturbed glucocorticoid rhythmicity. The resulting hyper-activation of the HPA axis at the sleep/wake transition drives time-of-day-specific impairments of the stress response and stress-sensitive behaviors. Finally, microbiota transplantation confirmed that diurnal oscillations of gut microbes underlie altered glucocorticoid secretion and that L. reuteri is a candidate strain for such effects. Our data offer compelling evidence that the microbiota regulates stress responsiveness in a circadian manner and is necessary to respond adaptively to stressors throughout the day.

The effects of stress on surgical performance: a systematic review

INTRODUCTION

Acute stress, the psychological response to short-term challenging stimuli, is frequently encountered in the high-pressure environment of the operating theatre. Surgeon stress is associated with deterioration in surgical performance, surgical team working and compromised patient safety. Given these concerns, the aim of this review was to understand the impact of acute stress on surgical performance in technical and non-technical domains as well as patient outcomes.

METHODS

A systematic review was conducted following PRISMA guidelines. Electronic databases were searched for studies examining acute stress in medical professionals during real or simulated surgical procedures that reported performance outcomes in technical and non-technical skills. Risk of bias assessment was conducted using appropriate tools for each study design.

RESULTS

Out of 1445 identified studies, 19 met the inclusion criteria. In simulated environments, acute stress consistently led to impairment in both technical and non-technical skills during surgical procedures. Technical skill deterioration included higher procedural error rates, longer task completion times and diminished instrument handling. Non-technical skills, such as teamwork and communication, also were impaired under stress conditions. Real-world studies echoed these findings, demonstrating acute stress resulting in higher error rates and impaired non-technical skills. No studies identified surgeon stress as having a causal relationship with patient outcomes.

CONCLUSION

Acute stress significantly impacts both technical and non-technical skills during surgical procedures, impairing performance in simulated and real-world surgical environments. Despite the growing understanding of the detrimental effects of stress, gaps remain in comprehensively assessing its impact on patient outcomes. Further research is warranted to develop reliable stress measurement methods applicable in surgical settings and explore effective stress management strategies.

Mitochondrial Functioning: Front and Center in Defining Psychosomatic Mechanisms of Allostasis in Health and Disease

There is increased awareness among basic and clinical scientists that psychological and social stress can have detrimental effects on physical, cognitive, and mental health. Data have been published indicating that social, economic, psychological, and physical environmental stress can influence behavior that has biological and physiological consequences-yet there are major gaps in understanding the physiological and cellular processes that drive increased morbidity and mortality. The potential role of mitochondria has been highlighted in psychosomatic medicine, as their functionality in various biological and physiological processes has earned recognition. This review outlines the essential role of mitochondria by considering the numerous intracellular, extracellular, and physiological functions it regulates that position the organelle as a central mediator in responses to psychological stress. We then connect these functions to mitochondrial allostasis and allostatic load for further examination of the limitations of mitochondria to an adaptive psychological stress response where mitochondrial allostatic load may eventually lead to systemic pathophysiology. This review emphasizes how chronic social, economic, and psychological stress can contribute to mitochondrial dysfunction and predispose individuals to poorer health outcomes and death. Mitochondrial capacity, function, and activity may therefore serve as biomarkers for identifying individuals at high risk for developing comorbid conditions related to their psychosocial environment.

Behavioral Consequences of Hippocampal 5-HT7 Receptors Blockade in Stressed Rats

Serotonin (5-HT) has long been involved in response to stress and its effect may be, in part, mediated by 5-HT1a and 5-HT7 receptor subtypes in different brain structures. Both pre- and post-synaptic activation of 5-HT1a receptor, respectively, in the rat median raphe nucleus (MnRN) and hippocampus, lead to adaptation to acute inescapable stressors such as restraint and forced swim. 5-HT7 receptor (5HT7r), a stimulatory G-protein coupled receptor, has also been investigated as a possible candidate for mediating stress response. In the MnRN, activation of 5-HT7r has antidepressant effects, while in the hippocampus, 5HT7r mRNA expression is increased after exposure to restraint stress, but the functional significance of these receptors remains to be determined. Therefore, the aim of this study was to investigate whether blockade of hippocampal 5HT7r would prevent and/or attenuate the behavioral effects of stress. Male adult Wistar rats with bilateral cannulas aimed at the dorsal hippocampus were restrained for 2 h and tested in the elevated plus maze (EPM) 24 h later. SB 258741 (3 nmoles/0.5 μL/side; selective 5HT7r antagonist) was administered bilateraly into the hippocampus according to the experimental protocol: immediately before or after stress, or 24 h after it (immediately before the test). In a second experiment, rats were exposed to 15 min. of forced swim, and tested 24 h later. Intra-hippocampal treatment was performed as described for the restraint stress protocol. We found that blockade of hippocampal 5-HT7r immediately after, but not before, the exposure to restraint or forced swim attenuated stress-induced behavioral changes. Similar results were obtained when SB was administered before the test in previously stressed rats. Our data suggest that activation of hippocampal 5-HT7r is crucial for the consolidation and retrieval of aversive stimulus-related memories, such as those caused by a stressful experience, probably through mechanisms involving stress-induced changes in 5-HT7r expression.

Nervous system in colorectal cancer

A malignant tumor is a complex systemic disease involving the nervous system, which regulates nerve signals. Cancer neuroscience is a field that explores the interactions between tumors and the nervous system. The gastrointestinal tract is a typical peripheral organ with abundant neuroregulation and is regulated by the peripheral, enteric, and central nervous systems (PNS, ENS, and CNS, respectively). The physiological functions of the gastrointestinal tract are maintained via complex neuromodulation. Neuroregulatory imbalance is the primary cause of gastrointestinal diseases, including colorectal cancer (CRC). In CRC, there is a direct interaction between the nervous system and tumor cells. Moreover, this tumor-nerve interaction can indirectly regulate the tumor microenvironment, including the microbiota, immunity, and metabolism. In addition to the lower nerve centers, the stress response, emotion, and cognition represented by the higher nerve centers also participate in the occurrence and progression of CRC. Herein, we review some basic knowledge regarding cancer neuroscience and elucidate the mechanism underlying tumor-nerve interactions in CRC.

Trait Anxiety Leads to "Better" Performance? A Study on Acute Stress and Uncertain Decision-Making

In uncertain situations, individuals seek to maximize rewards while managing risks. Yet, the effects of acute stress and anxiety on decision-making in ambiguous and risky contexts are unclear. This study aims to contribute to the exploration of how acute stress influences sensitivity to immediate vs. delayed rewards, risk management strategies, and the role of anxiety in these processes. This study used the laboratory acute stress induction paradigm to analyze the direction of influence of acute stress on ambiguity decision-making and risky decision-making in males and then used moderating effect analysis to study the impact of anxiety on this process. The results show that a combination of the Socially Evaluated Cold Pressor Test and the Sing-a-Song Stress Test can successfully induce acute stress, which reduces both the proportion of the options selected that represent long-term rewards and risk-adjustment ability. Additionally, trait anxiety had a moderating effect on the influence of stress on ambiguity decision-making. Acute stress reduces focus on long-term rewards while increasing focus on short-term rewards, leading to impulsivity and impaired risk-adjustment. Additionally, to some extent, high trait anxiety scores predict better performance in making decisions under ambiguity during stress.

Psychometric properties of the Arabic Stress Numerical Rating Scale (SNRS-11) in adolescents

Meta-analytic results have revealed a significant influence of stress on a wide array of psychological and behavioral markers, underscoring its considerable clinical importance. Providing a simple and cost-effective tool assessing stress for the Arabic-speaking population would be immensely beneficial. Therefore, our research objective was to examine the psychometric properties of an Arabic version of the Stress Numerical Rating Scale-11 (Arabic SNRS-11), including its reliability, and construct validity. 763 adolescents were recruited during November 2023. An anonymous self-administered Google Forms link was distributed via social media networks. The results of the EFA revealed two factors, which explained 66.43% of the common variance. When adding the SNRS-11, Bartlett's test of sphericity, χ2(55) = 4127.1, p < 0.001, and KMO (0.88) remained adequate. The two-factor solution obtained explained 63.28% of the variance. The same structure was obtained in both males and females separately. McDonald's ω and Cronbach's α were very good for all models. Both PSS and Arabic SNRS-11 scores correlated significantly and positively with each other, as well as with higher depression, anxiety and stress scores. Finally, no significant difference was found between males and females in terms of PSS (27.08 ± 6.43 vs. 27.72 ± 6.06; p = 0.163; Cohen's d = 0.102) and Arabic SNRS-11 (4.68 ± 2.56 vs. 4.97 ± 2.52; p = 0.125; Cohen's d = 0.113) scores. The findings indicate that the Arabic SNRS-11 is a cost-effective, valid, and reliable tool for assessing stress. Therefore, it is recommended to use this single item to assess momentary or day-to-day stress among Arabic-speaking adolescents in Arab clinical and research settings. To evaluate the practical effectiveness of the Arabic SNRS-11 and to further enhance the data on its construct validity, future studies should assess the measure in diverse contexts and among specific populations.