Search Results (246)

Background: Insomnia is prevalent and difficult to treat safely over the long term. Given the role of the microbiota–gut–brain axis in melatonin and hypothalamic–pituitary–adrenal (HPA) regulation, and preclinical evidence for Limosilactobacillus fermentum PS150, we evaluated whether a heat-treated formulation (HT-PS150) could improve sleep and modulate endocrine/circadian markers in adults with poor sleep. Methods: In a randomized, double-blind, placebo-controlled trial, 84 adults aged 20–60 years with PSQI ≥ 5 and ISI < 22 were assigned to receive either placebo or HT-PS150 for eight weeks. Outcomes included patient-reported sleep (PSQI, ISI), anxiety/depression (GAD-7, PHQ-9), quality of life (QLESQ-SF), gastrointestinal symptoms (VAS-GI), wrist actigraphy (Fitbit Inspire 3), and sleep-relevant biomarkers measured from urine, saliva, and/or blood samples (melatonin, cortisol, orexin, serotonin, GABA, and/or norepinephrine). Repeated measures were analyzed using generalized estimating equations. An exploratory proportional regulation analysis classified individual biomarker changes as up- or down-regulated and compared proportions between study arms. Per-protocol analyses required ≥80% compliance. Results: Improvements in the primary outcomes, PSQI and ISI, were observed over time in both groups, while no significant group × time interactions were detected. In exploratory proportional analyses, a higher proportion of participants in the HT-PS150 group exhibited up-regulated nocturnal melatonin secretion and improved daytime plasma orexin levels, as well as a tendency toward greater reductions in nocturnal salivary cortisol compared with placebo. In subgroup analyses with higher baseline insomnia severity (ISI ≥ 8), HT-PS150 was associated with greater improvements in PSQI (notably sleep duration and efficiency) and reduction in anxiety (GAD-7) upon post hoc testing. Conclusions: Although group mean scores on sleep symptom scales did not differ significantly in the full cohort, HT-PS150 appeared to modulate sleep–wake regulation by enhancing nocturnal melatonin secretion, attenuating HPA-axis activity, and stabilizing wakefulness. Clinical benefits were most evident among participants with greater baseline symptom burden, suggesting potential utility in more symptomatic populations. Full article

The gut-brain axis is a complex communication network linking the gastrointestinal tract and the central nervous system, in which the gut microbiota plays a pivotal role in regulating intestinal homeostasis, immune responses and neuroendocrine functions. This review summarizes current knowledge on the role of the porcine gut microbiota in the functioning of the gut-brain axis and examines nutritional strategies aimed at its modulation. Key production-related stressors, such as weaning, transport and handling, disrupt microbiota composition, increase intestinal permeability and activate the hypothalamic-pituitary-adrenal (HPA) axis, leading to heightened stress responses, impaired immunity and behavioral disturbances. Evidence indicates that supplementation with probiotics, prebiotics, or postbiotics stabilizes the gut microbiota, enhances the production of bioactive metabolites, supports intestinal barrier integrity and alleviates oxidative stress. Such interventions improve adaptation to environmental stress, animal welfare and performance, while potentially reducing the need for antibiotics. Maintaining a balanced gut microbiota is therefore essential for the proper functioning of the neuroendocrine and immune systems in pigs. An integrated approach utilizing omics technologies (metagenomics, metabolomics, proteomics) may further elucidate microbiota-brain interactions and support the development of sustainable and ethical swine production strategies. Full article

It has been demonstrated that prolonged exposure to stress engenders a plethora of neuropsychiatric, immune and metabolic disorders. However, its pathophysiology transcends the conventional hypothalamic–pituitary–adrenal (HPA) axis. This review addresses the central question of how integrated neural and microbial pathways regulate stress responses and resilience. We present a model in which the parasympathetic nervous system (particularly the vagus nerve) and the gut microbiota interact to form a bidirectional neuroimmune network that modulates the HPA axis, immune function, neurotransmitter balance, and metabolic adaptation. Key molecular pathways include nitric oxide synthesis via the classical nitric oxide synthase (NOS)-dependent and microbiota-mediated nitrate–nitrite routes, inducible nitric oxide synthase (iNOS) regulation, nuclear factor erythroid 2-related factor 2 (Nrf2) signalling, lysosomal function, autophagy and the cholinergic anti-inflammatory reflex. Other pathways include the gamma-aminobutyric acid (GABA) and serotonin (5-HT) systems, NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) signalling, polyamine metabolism and peroxisome proliferator-activated receptor gamma (PPARγ). Intermittent hypoxia training (IHT) enhances mitochondrial function, oxidative stress responses, autonomic balance and gut microbiota composition. This promotes parasympathetic activity and stress resilience that is tailored to the individual. These adaptations support the concept of personalised stress response profiles based on hypoxic adaptability. Clinical implications include combining IHT with vagus nerve stimulation, probiotics, dietary strategies, and stress reduction techniques. Monitoring vagal tone and microbiota composition could also serve as predictive biomarkers for personalised interventions in stress-related disorders. This integrative framework highlights the therapeutic potential of targeting the parasympathetic system and the gut microbiota to modulate stress. Full article

The resin extract of Garcinia nigrolineata (GNR-E), a tropical plant used in Southeast Asian traditional medicine, was evaluated for its antidepressant-like effects in a chronic mild stress (CMS) mouse model, with imipramine as a reference drug. GNR-E dose-dependently alleviated CMS-induced anhedonia (sucrose preference test) and behavioral despair (forced swimming and tail suspension tests). Neurochemical analyses revealed that GNR-E increased serotonin (5-HT) and norepinephrine (NE) levels, reduced expression of their transporters (SERT, NET) and receptors (5-HT1A, 1B, 2A, 2C, 7; α2A, 2C) in the frontal cortex and hippocampus, and normalized HPA-axis hyperactivity by lowering serum corticosterone and modulating glucocorticoid receptor (GR) and SGK-1 mRNA expression. In vitro, GNR-E inhibited monoamine oxidase (MAO)-A and -B (Ki = 2.33 and 1.55 µg/mL, respectively). Phytochemical analysis identified xanthones, particularly cowanin, as key constituents. These findings highlight GNR-E’s potential as a novel plant-based antidepressant, warranting further investigation into its active compounds and clinical applications. Full article

Obesity and depression are two of the most prevalent diseases with increasing trends worldwide; it has been some time since the first epidemiological associations were first described. Currently, there is abundant evidence showing the physiology and the molecular aspects that intersect the biology of both ailments. This narrative review aims to synthesize current evidence on the epidemiology and shared pathophysiology of obesity and major depressive disorder, emphasizing convergent inflammatory, neuroendocrine, metabolic, genetic, and gut–brain mechanisms. We aggregate evidence for a bidirectional relationship mediated by: (1) chronic low-grade inflammation (elevated CRP, IL-6, TNF-α; microglial activation); (2) HPA axis dysregulation (hyper/corticosteronemia, impaired feedback, altered CRH/ACTH signaling); (3) metabolic and neurotrophic signaling deficits (insulin and leptin resistance, dysregulated adipokines such as leptin/adiponectin, impaired BDNF and synaptic plasticity); (4) lipid-derived neurotoxicity and mitochondrial stress (saturated fatty acids, ceramides, oxidative stress); and (5) gut–brain axis perturbations (microbiota dysbiosis, increased intestinal permeability, LPS-driven endotoxemia, altered short-chain fatty acids and tryptophan–kynurenine metabolism). We highlight how these convergent pathways promote neuroinflammation and mood dysregulation in individuals with obesity and summarize clinical consequences for screening, integrated management, and targeted interventions that modulate immune, neuroendocrine, metabolic, and microbial processes. Finally, we outline priorities for identifying shared biomarkers and advancing personalized strategies via multi-omics and systems medicine to improve prevention, diagnosis, and treatment. Full article

Bipolar disorder (BD) is a severe psychiatric illness characterized by recurrent mood episodes and significant psychosocial impairment. Emerging evidence supports a bidirectional link between diet and mental health, with growing interest in nutritional psychiatry. This narrative review examines the psychological and psychiatric impact of diet in BD, focusing on biological mechanisms (gut–brain axis, neuroinflammation, oxidative stress, neurotransmitter synthesis, and HPA axis dysregulation) and the role of specific dietary patterns, including Western, Mediterranean, ketogenic, and anti-inflammatory diets. Key micronutrients such as omega-3 fatty acids, B-vitamins, magnesium, and vitamin D are explored in relation to mood regulation. This review also addresses psychological factors, including emotional eating, disordered eating behaviors, and the symbolic meaning of food in BD. Furthermore, it highlights the integration of nutritional psychoeducation into psychotherapy, the impact of comorbidities (e.g., obesity, metabolic syndrome), and the role of lifestyle factors such as sleep and physical activity. Despite promising findings, current research is limited by methodological heterogeneity. Future perspectives should include interdisciplinary, personalized interventions that incorporate nutritional strategies into standard care for BD. Full article

Chronic low-grade systemic inflammation is increasingly recognized as a key mediator linking stress, pain sensitivity, and cognitive decline. Central to this process are the acute-phase reactants interleukin-6 (IL-6) and C-reactive protein (CRP), which serve as biomarkers of systemic inflammation while promoting neuroimmune dysregulation. Emerging evidence implicates the IL-6–CRP axis in the amplification of pain perception, central sensitization, and stress hypersensitivity, ultimately promoting neurodegenerative processes such as those observed in Alzheimer’s disease (AD) and vascular dementia. Monomeric CRP (mCRP), a proinflammatory isoform generated under mechanical or oxidative stress, can trigger histone modifications (e.g., H3 citrullination), activate endothelial and immune cells, and exacerbate inflammatory pain pathways. These mechanisms are further modulated by genetic and epigenetic factors, including IL-6/CRP/NR3C1 gene variant expression; promoter methylation; and stress-responsive microRNAs, which intersect with dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis, impairing immune resolution and neurocognitive resilience. Psychosocial stressors, such as the burden of caregiving or perfectionistic cognitive patterns, amplify IL-6 and CRP levels, particularly when pain is present, suggesting a synergistic interaction between emotional distress and somatic inflammation. Specifically, elevated CRP is associated with increased pain sensitivity, lower pain thresholds, and cognitive decline even in subclinical populations, providing a feedforward model in which chronic stress and pain potentiate systemic inflammation, disrupt neuroendocrine feedback, and accelerate neurodegenerative pathology. However, in this model, the potentially critical mechanistic and pathological role of mCRP remains to be discovered. This review addresses the missing elements of these overlapping pathways and discusses the therapeutic potential of targeting IL-6–CRP signaling, stress regulation, and epigenetic modifiers as strategies to ameliorate inflammation-driven cognitive decline and enhance stress resistance in chronic disease contexts. We propose that plasma mCRP or more likely the isoform-aware metric, the mCRP/CRP ratio, will provide a biologically anchored, potentially more discriminative approach to vascular-neuroimmune risk and capture the propensity for local effector signaling, likely outperforming hs-CRP or IL-6 alone for risk stratification across neurovascular and stress-sensitized pain phenotypes. Full article

Background: Post-traumatic stress disorder (PTSD) is a mental disorder that can develop after experiencing or witnessing a traumatic event. Dysfunction of the hypothalamic–pituitary–adrenal (HPA) axis and alterations in neurotransmitters (gamma-aminobutyric acid (GABA) and glutamate) are the main pathologies of PTSD. In particular, altered GABAergic neurotransmission and reduced GABA activity are linked to PTSD. Given the low efficacy and side effects of serotonin reuptake inhibitors—the most common treatment for PTSD—a safer and more effective treatment is urgently needed. Bojungikgi-tang (BJIGT) is well-known herbal prescription in East Asia, which used to boost immunity and to alleviated symptoms such as chronic fatigue, poor appetite, and indigestion. However, its role in PTSD remains largely unexamined. This study aimed to investigate the effects of BJIGT in single-prolonged stress with shock (SPSS)-induced PTSD male mice for 2 weeks. Methods: To assess PTSD-like behaviors, we conducted open field, forced swimming, Y-maze, and contextual fear conditioning tests. To investigate the underlying mechanisms, we performed ELISA, Western blot, and immunohistochemistry. Results: BJIGT significantly ameliorated PTSD-like behaviors, including emotional and cognitive decline. Additionally, it restored serum corticosterone levels, regulated neuronal functions (c-Fos, DCX, and Prox1), and GABAergic neurotransmission-related factors (vGAT, GAD67, and parvalbumin) in the hippocampus of PTSD mice. Notably, in SPSS-induced PTSD mice, BJIGT effectively ameliorated pathological changes by modulating JNK-CaMKII and Pin1–β-catenin intracellular signaling. Conclusions: These findings revealed that BJIGT effectively improved PTSD-like emotional and cognitive decline by regulating the HPA axis and GABAergic neurotransmission in SPSS-induced PTSD mice, thereby promising to be an effective strategy for the treatment of PTSD. Full article

Stress is a non-specific systemic response to internal or external challenges. Recent studies show that stress can disrupt iron metabolism and that iron dyshomeostasis is implicated in many diseases-particularly within the nervous system, where iron distribution and regulation intersect tightly with oxidative stress and inflammation. Activation of the hypothalamic–pituitary–adrenal (HPA) axis by stress can upregulate hepatic hepcidin and reprogram systemic iron fluxes, leading to functional iron deficiency and, in the brain, reduced iron availability, which affects myelination and neurotransmitter metabolism. Conversely, iron dyshomeostasis also contributes to neurodegenerative pathology. In this review, we synthesize recent evidence of how stress reprograms brain iron distribution and regulation, and we outline the mechanistic links between stress-induced iron dysregulation and neurological pathology. We also discuss the therapeutic implications (such as iron-chelation strategies) and highlight the three-way interplay among stress, iron metabolism, and neurodegeneration. These insights suggest that managing iron homeostasis may offer new therapeutic avenues for stress-related neural disorders. Full article

In birds, light can penetrate the cranial bones and reach deep brain regions, where non-visual photoreceptors, especially in the hypothalamus, detect spectral and photoperiodic cues. Alongside retinal photoreception, deep-brain light sensing contributes to circadian entrainment and regulates melatonin secretion by the pineal gland. These light-driven pathways modulate endocrine activity, playing a key role in muscle development. This review explores how monochromatic light-emitting diode (LED) illumination, particularly green and blue wavelengths, affects the somatotropic axis (growth hormone-releasing hormone [GHRH]-growth hormone [GH]-insulin-like growth factor 1 [IGF-1]), the gonadal axis (gonadotropin-releasing hormone [GnRH]-luteinizing hormone [LH]/follicle-stimulating hormone [FSH]-sex steroids [testosterone, estrogen, progesterone]), the thyroid axis (thyrotropin-releasing hormone [TRH]-thyroid-stimulating hormone [TSH]-thyroxine [T₄]/triiodothyronine [T₃]), and the hypothalamic-pituitary-adrenal (HPA) axis (corticotropin-releasing hormone [CRH]-adrenocorticotropic hormone [ACTH]-corticosterone). Green light enhances early-stage muscle growth via GHRH and IGF-1 upregulation, while blue light supports later myogenic activity and oxidative balance. Light schedules also influence melatonin dynamics, which in turn modulate endocrine axis responsiveness to photic cues. Furthermore, variations in photoperiod and exposure to artificial lights at night (ALAN) affect thyroid activity and HPA axis reactivity, influencing metabolism, thermoregulation, and stress resilience. Together, ocular and intracranial photoreception form a complex network that links environmental light to hormonal regulation and muscle growth. These insights support the strategic use of LED lighting to optimize broiler performance and welfare. Full article

Burnout is increasingly recognized as both a psychosocial and a chronobiological disorder characterized by endocrine dysregulation and circadian disruption. It arises from chronic occupational stress and manifests through psychological, physical, and physiological symptoms. Although psychosocial determinants are well established, the biological and chronobiological mechanisms, particularly those involving cortisol and melatonin, remain less explored. This systematic review synthesizes current evidence on hormonal and circadian dysregulation in burnout and complements it with exploratory observational data from healthcare professionals. Peer-reviewed studies evaluating endocrine or circadian biomarkers in individuals with burnout were systematically reviewed. In addition, an exploratory observational analysis was carried out among 195 Romanian clinicians using an adapted Maslach Burnout Inventory. Morning salivary cortisol was measured once at 9 a.m. in a small subsample (n = 26) to provide preliminary physiological data. Because only a single time point was obtained, these values were interpreted as indicative of stress-related activation rather than circadian rhythm. Thirty-seven studies met the inclusion criteria. Across the literature, burnout was associated with altered HPA-axis activity, blunted diurnal cortisol variation, and irregular melatonin secretion related to shift work and disrupted sleep–wake cycles. Complementary exploratory data from our Romanian cohort indicated strong correlations between burnout severity, physical symptoms, and higher morning cortisol values among shift-working clinicians. These findings are preliminary and not representative of full circadian profiles. Burnout should be considered both a psychosocial and a systemic disorder influenced by endocrine and circadian dysregulation. Recognizing alterations in cortisol and melatonin as objective indicators may facilitate earlier detection and inform chronobiological interventions such as optimized scheduling, light exposure management, or melatonin therapy. The observational data presented here is preliminary and intended to generate hypotheses; future research should employ repeated cortisol sampling under controlled Zeitgeber conditions to confirm circadian associations. Full article

Treatment-resistant depression (TRD) affects 20–30% of patients with major depressive disorder and presents a significant clinical challenge due to its biological diversity. This review highlights standard mechanisms that contribute to treatment resistance beyond traditional monoaminergic models. Evidence supports serotonergic dysregulation, including 5-HT1A autoreceptor dysfunction and “serotonin flooding” as well as dopaminergic deficits linked to anhedonia and an imbalance between glutamate and GABA that impair synaptic plasticity. Changes in neurotrophic signaling, such as reduced BDNF and VEGF activity, complicate recovery by limiting neural repair and regeneration. Chronic inflammation and oxidative stress contribute to neuronal dysfunction, while HPA axis dysregulation may exacerbate depressive symptoms and resistance to antidepressants. Emerging evidence suggests that obesity and gut microbiota imbalance reduce the production of short-chain fatty acids by bacteria and increase intestinal permeability, thereby influencing neuroinflammatory and neurochemical processes in TRD. Neuroimaging studies reveal hyperconnectivity within the default mode network and impaired reward circuits, both of which are associated with persistent symptoms and a poor treatment response. By combining evidence on inflammation, oxidative stress, neuroendocrine disturbances, microbiome changes, and brain connectivity issues, this review develops a comprehensive framework for understanding TRD. It emphasizes the importance of biomarker-based subtyping to guide personalized future treatments. Full article

This review aims to synthesize current evidence on the role of chronic stress and hypothalamic–pituitary–adrenal (HPA) axis dysregulation in the pathogenesis of chronic kidney disease (CKD). The focus is on the interplay between cortisol, oxidative stress, inflammation, and metabolic risk factors within the psycho-neuro-endocrine-immune (PNEI) system. CKD is a multifactorial disease characterized by oxidative stress, chronic low-grade inflammation, and neuroendocrine imbalance. These processes interact to accelerate renal injury and systemic complications. Pro-inflammatory mediators such as tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6), together with oxidative stress markers including malondialdehyde (MDA), advanced oxidation protein products (AOPPs), and 8-hydroxy-2′-deoxyguanosine (8-OHdG), are strongly associated with disease progression. Altered cortisol dynamics—assessed in serum, saliva, and hair—further reflect chronic HPA activation and contribute to immune dysfunction, metabolic disturbances, and cardiovascular risk. By integrating experimental and clinical findings, this review highlights how stress-induced dysregulation of the PNEI system amplifies CKD progression. Understanding these interconnected mechanisms underscores the potential of combining oxidative, inflammatory, and neuroendocrine biomarkers for improved risk stratification and targeted therapeutic interventions. Full article

Many individuals suffer from sleep disorders associated with chronic pain, neuroendocrine diseases, and primary sleep disorders. Although cervical manual therapy (CMT) is frequently presumed to enhance sleep quality in clinical settings, evidence regarding its effects on sleep remains inconclusive. We aimed to evaluate the therapeutic effect of CMT and clinical patterns, providing novel insights into its applicability for sleep disorders and further mechanism studies. Methods: A comprehensive literature survey was conducted by using 6 databases through February 2025, to identify randomized controlled trials (RCTs) assessing the effect of CMT on sleep quality as clinical outcome, regardless of primary diseases. Results: Among 1220 initial studies, a total of 10 RCTs involving 552 participants were included. All included RCTs assessed sleep quality using patient-reported outcome measures, while only one study utilized objective assessment via polysomnography. Among them, seven RCTs (70.0%) reported significant improvements in sleep quality that were not dependent on alleviating the primary diseases, with notable enhancements in subjective sleep depth and efficiency rather than sleep duration or latency. Sleep benefits were pronounced in primary sleep disorders, such as obstructive sleep apnea and bruxism, and in sleep disturbances secondary to other conditions, with limited effects in fibromyalgia (FM). Conclusions: With the dysregulated hypothalamic–pituitary–adrenal axis and aberrant serotonergic activity in FM, in this review, we formed a hypothesis and explored the potential effects of CMT on sleep-related serotonergic activity and HPA axis regulation. This scoping review underscores the need for further research to clarify the neuroendocrinological mechanisms underlying CMT’s role in sleep modulation and its potential applications in sleep-related disorders. Full article

Endocrine axes are pathways of interactions involved in various aspects of the organism’s functioning, also implicated in deviations from physiological states leading to pathological conditions. The hypothalamic–pituitary–adrenal (HPA) axis releases corticosteroid hormones promoting adaptation to environmental stimuli (acute stress) or inducing altered conditions due to long-term noxious solicitations (chronic stress). The HP–gonadal (HPG) axis regulates reproductive activities by releasing gonadal steroids. These axes have been shown to engage in reciprocal inhibition under certain conditions, particularly when they rise beyond normal ultradian and circadian fluctuations. Based on the literature data, we reconstructed a neuroendocrine network responsible for this type of interaction. Thereafter, we developed a model of the HPA-HPG inhibition based on a series of nonlinear interactions represented by a system of differential equations in the Matlab environment. The quantitative analysis of the system’s behavior revealed the occurrence of bifurcations leading to bistable behavior, allowing us to detect bifurcation parameters. Bifurcation arises as the system’s components increase hypersensitivity and sustained activity in response to activating inputs. This involves transition from a single low-activity attractor to two distinct attractors, with a new high-activity state representing a breakdown of homeostasis. These results provide insights into the potential involvement of the HPA-HPG interaction in neuroendocrine disorders, and the identification of therapeutic targets from bifurcation parameters. Full article