Your browser does not allow saving data (e.g. private mode): bookmarks will be lost when the tab closes.
Search PubMed
Keywords, author, journal, years — results from PubMed, abstracts with Russian translation, bookmarks in your browser.
Found: 3 214
Page 286 of 322-
Gut Feelings: Vagal Stimulation Reduces Emotional Biases.
The vagus nerve is a key physical constituent of the gut-brain axis. Increasing attention has recently been paid to the role that the gut, and the microorganisms inhabiting it, play in emotion and cognition. Animal studies have revealed the importance of the vagus nerve in mediating communication between the gut microbiome and the central nervous system, resulting in changes in emotional behaviour. This has renewed interest in understanding the role of vagal signalling in human emotion, particularly since human studies have also shown that alterations in gut microbiome composition can affect emotion. While stimulating the vagus nerve can help treat some cases of severe depression, here we investigate whether vagal afferent signalling can influence emotional processing in healthy subjects. We use the dot-probe task to determine the effect of transcutaneous vagus nerve stimulation on attentional biases towards emotional stimuli in 42 volunteers. Participants received both active and sham treatments using a within-subject design. We show that transcutaneous vagus nerve stimulation reduces the emotional bias towards faces expressing sadness and happiness, indicating a decrease in emotional reactivity. While our novel findings reveal the effect that vagal signalling can have on emotional biases in healthy subjects, future studies should seek to develop our understanding of the ways in which the microbiome interacts with, and stimulates, the vagus nerve. Since we find a reduction in emotional bias, most notably towards sadness, this may partly account for the effective use of vagus nerve stimulation in treatment-resistant depression. While its clinical application currently involves surgical stimulation, our results support the potential benefit of transcutaneous vagus nerve stimulation as a non-invasive, intermittent adjunctive therapy for patients with depression, given its frequent association with emotional biases.
-
The aryl hydrocarbon receptor and kynurenine pathway: connecting inflammatory bowel disease and depression via the microbiota gut brain axis.
Inflammatory bowel disease (IBD) is a disorder characterized by chronic inflammation in the gastrointestinal (GI) tract. This disease has a complex etiology with major contributing factors including genetics, host-microbiome interactions, dysregulation of the immune response, and various environmental triggers. The negative impacts of IBD are not limited to the GI tract however, as IBD patients also develop extraintestinal manifestations involving multiple organs and organ systems. In support of this, IBD patients have increased incidence of mood and behavioral disorders, such as depression, which are often attributed to the concept known as the microbiota gut brain axis (MGBA). This concept refers to the bidirectional communication between the GI tract and central nervous system (CNS) via key components. While it is clear IBD and depression often manifest together, it remains unclear what major mechanisms drive this relationship. Growing evidence suggests that the aryl hydrocarbon receptor (AhR) impacts disease severity in both IBD and behavioral disorders. The purpose of this review is to summarize IBD and depression with emphasis on the potential role AhR plays in both disorders. In addition, evidence of the kynurenine pathway (KP) in IBD and depression will be discussed with particular focus on how this biochemical pathway is linked to both the activation of AhR and its regulation, thus making it an interesting connection requiring further investigation. This review will also summarize key mechanisms of the MGBA implicated in the comorbidity of IBD and depression highlighting the impact, if any, AhR and KP play in these factors. Lastly, the review will discuss limitations of this current topic and any potential future directions to better understand the roles of AhR and KP in comorbid IBD and depression.
-
Microbiome-Driven Proline Biogenesis in Plants under Stress: Perspectives for Balanced Diet to Minimize Depression Disorders in Humans.
According to the World Health Organization (WHO), depression is a leading cause of disability worldwide and a major contributor to the overall global burden of mental disorders. An increasing number of studies have revealed that among 20 different amino acids, high proline consumption is a dietary factor with the strongest impact on depression in humans and animals, including insects. Recent studies acknowledged that gut microbiota play a key role in proline-related pathophysiology of depression. In addition, the multi-omics approach has alleged that a high level of metabolite proline is directly linked to depression severity, while variations in levels of circulating proline are dependent on microbiome composition. The gut-brain axis proline analysis is a gut microbiome model of studying depression, highlighting the critical importance of diet, but nothing is known about the role of the plant microbiome-food axis in determining proline concentration in the diet and thus about preventing excessive proline intake through food consumption. In this paper, we discuss the protocooperative potential of a holistic study approach combining the microbiota-gut-brain axis with the microbiota-plant-food-diet axis, as both are involved in proline biogenesis and metabolism and thus on in its effect on mood and cognitive function. In preharvest agriculture, the main scientific focus must be directed towards plant symbiotic endophytes, as scavengers of abiotic stresses in plants and modulators of high proline concentration in crops/legumes/vegetables under climate change. It is also implied that postharvest agriculture-including industrial food processing-may be critical in designing a proline-balanced diet, especially if corroborated with microbiome-based preharvest agriculture, within a circular agrifood system. The microbiome is suggested as a target for selecting beneficial plant endophytes in aiming for a balanced dietary proline content, as it is involved in the physiology and energy metabolism of eukaryotic plant/human/animal/insect hosts, i.e., in core aspects of this amino acid network, while opening new venues for an efficient treatment of depression that can be adapted to vast groups of consumers and patients. In that regard, the use of artificial intelligence (AI) and molecular biomarkers combined with rapid and non-destructive imaging technologies were also discussed in the scope of enhancing integrative science outcomes, agricultural efficiencies, and diagnostic medical precisions.
-
The role of gut microbiota in the pathogenesis and treatment of postpartum depression.
Postpartum depression (PPD) is a common complication of pregnancy in women, and its pathogenesis mainly involves disturbances of the neuroendocrine regulation, immune system, neurotransmitters, hormone secretion, and the gut microbiome. Gut microbes play essential physiological and pathological roles in the gut-brain axis' pathways which are involved in various central nervous system (CNS) and psychiatric disorders, including PPD. Numerous studies have identified the fundamental role of the gut-brain axis in the pathogenesis and treatment of PPD patients and also correlates with other pathogenic mechanisms of PPD. Disturbances in gut microbes are associated with the disruption of multiple signaling pathways and systems that ultimately lead to PPD development. This review aimed to elucidate the potential connections between gut microbes and the established PPD network, and this might serve as a guide for the development of new efficient diagnostic, therapeutic, and prognostic strategies in the management of PPD.
-
Stressor-Specific Microbiota Intervention.
To date, mental disorders are diagnosed and treated by the subjective judgment of psychiatrists based on diagnostic criteria and treatment guidelines, respectively. Mental disorders are heterogeneous illnesses with a substantial treatment-refractory rate. Thus, there is a great need for novel treatment approaches. This article proposes a treatment approach centered on the concept of the gut-brain axis. There is mounting evidence indicating an association between stressors, microbiota, microglia, and mental disorders. Stressors might facilitate dysbiosis, inflammation, and the occurrence of mental disorders. This novel treatment approach is based on the idea that stressor types instead of the heterogeneous psychiatric diagnosis might be closer to the neurobiological underpinnings of mental disorders. First of all, patients with treatment-resistant mental disorders will be asked to describe their major stressors. Then, clinicians will calculate the total threat score and the total deprivation score. Subsequently, treatment tailored to the major stressor type will be administered to restore a healthy gut microbiome. Presumably, treatment will be aimed at increasing microbiota diversity in those who mainly have deprivation stressors and boosting Actinobacteria in those who have mainly threat stressors. Large-scale clinical trials are warranted to test this hypothetical approach.
-
Lactobacillus fermentum HNU312 alleviated oxidative damage and behavioural abnormalities during brain development in early life induced by chronic lead exposure.
Lead exposure is a global public health safety issue that severely disrupts brain development and causes damage to the nervous system in early life. Probiotics and gut microbes have been highlighted for their critical roles in mitigating lead toxicity. However, the underlying mechanisms by which they work yet to be fully explored. Here, we designed a two-stage experiment using the probiotic Lactobacillus fermentum HNU312 (Lf312) to uncover how probiotics alleviate lead toxicity to the brain during early life. First, we explored the tolerance and adsorption of Lf312 to lead in vitro. Second, the adsorption capacity of the strain was determined and confirmed in vivo. The shotgun metagenome sequencing showed lead exposure-induced imbalance and dysfunction of the gut microbiome. In contrast, Lf312 intake significantly modulated the structure of the microbiome, increased the abundance of beneficial bacteria and short-chain fatty acids (SCFAs)-producing bacteria, and upregulated function-related metabolic pathways such as antioxidants. Notably, Lf312 enhanced the integrity of the blood-brain barrier by increasing the levels of SCFAs in the gut, alleviated inflammation in the brain, and ultimately improved anxiety-like and depression-like behaviours induced by lead exposure in mice. Subsequently, the effective mechanism was confirmed, highlighting that Lf312 worked through integrated strategies, including ionic adsorption and microbiota-gut-brain axis regulation. Collectively, this work elucidated the mechanism by which the gut microbiota mitigates the toxic effects of lead in the brain and provides preventive measures and intervention measures for brain damage due to mass lead poisoning in children.
-
Probiotics reduce negative mood over time: the value of daily self-reports in detecting effects.
The burgeoning field of the microbiome-gut-brain axis has inspired research into how the gut microbiome can affect human emotion. Probiotics offer ways to investigate microbial-based interventions but results have been mixed, with more evidence of beneficial effects in clinically depressed patients. Using a randomised, double-blind, placebo-controlled design in 88 healthy volunteers, we conduct a comprehensive study into effects of a multispecies probiotic on emotion regulation and mood through questionnaires, emotional processing tests and daily reports. We find clear evidence that probiotics reduce negative mood, starting after two weeks, based on daily monitoring, but few other changes. Our findings reconcile inconsistencies of previous studies, revealing that commonly used pre- versus post-intervention assessments cannot reliably detect probiotic-induced changes in healthy subjects' emotional state. We conclude that probiotics can benefit mental health in the general population and identify traits of individuals who derive greatest benefit, allowing future targeting of at-risk individuals.
-
Gut Microbiome Signatures of Risk and Prodromal Markers of Parkinson Disease.
OBJECTIVE: Alterations of the gut microbiome in Parkinson disease (PD) have been repeatedly demonstrated. However, little is known about whether such alterations precede disease onset and how they relate to risk and prodromal markers of PD. We investigated associations of these features with gut microbiome composition. METHODS: Established risk and prodromal markers of PD as well as factors related to diet/lifestyle, bowel function, and medication were studied in relation to bacterial α-/β-diversity, enterotypes, and differential abundance in stool samples of 666 elderly TREND (Tübingen Evaluation of Risk Factors for Early Detection of Neurodegeneration) study participants. RESULTS: Among risk and prodromal markers, physical inactivity, occupational solvent exposure, and constipation showed associations with α-diversity. Physical inactivity, sex, constipation, possible rapid eye movement sleep behavior disorder (RBD), and smoking were associated with β-diversity. Subthreshold parkinsonism and physical inactivity showed an interaction effect. Among other factors, age and urate-lowering medication were associated with α- and β-diversity. Constipation was highest in individuals with the Firmicutes-enriched enterotype, and physical inactivity was most frequent in the Bacteroides-enriched enterotype. Constipation was lowest and subthreshold parkinsonism least frequent in individuals with the Prevotella-enriched enterotype. Differentially abundant taxa were linked to constipation, physical inactivity, possible RBD, smoking, and subthreshold parkinsonism. Substantia nigra hyperechogenicity, olfactory loss, depression, orthostatic hypotension, urinary/erectile dysfunction, PD family history, and the prodromal PD probability showed no significant microbiome associations. INTERPRETATION: Several risk and prodromal markers of PD are associated with gut microbiome composition. However, the impact of the gut microbiome on PD risk and potential microbiome-dependent subtypes in the prodrome of PD need further investigation based on prospective clinical and (multi)omics data in incident PD cases. ANN NEUROL 2021;90:E1-E12.
-
The role of probiotics and prebiotics in modulating of the gut-brain axis.
Pro-and prebiotics have been indicated to modulate the gut-brain axis, which have supportive impacts on central nervous systems, and decrease or control the incidence of some mental disorders such as depression, anxiety, autism, Schizophrenia, and Alzheimer's. In this review, complex communications among microbiota, gut, and the brain, and also recent scientific findings of the impacts and possible action mechanisms of pro-and prebiotics on mental disorders have been discussed. The results have shown that pro-and prebiotics can improve the function of central nervous system and play an important role in the prevention and treatment of some brain disorders; however, in order to prove these effects conclusively and firmly and to use these compounds in a therapeutic and supportive way, more studies are needed, especially human studies/clinical trials.
-
Investigating the Microbiome in Relation to Mental Distress Across Two Points During Pregnancy: Data From U.S. and Swedish Cohorts.
BACKGROUND: In this study, we aimed to characterize the gut microbiome and its potential functioning in 2 populations at 2 time points during pregnancy in relation to mental distress. METHODS: During the second and third trimester, individuals from the United States and Sweden completed the Edinburgh Postnatal Depression Scale and provided fecal samples for whole-genome metagenomics. A total of 832 and 161 samples were sequenced and analyzed from the Swedish cohort and the U.S. cohort, respectively. Multiple characterizations of the microbial community were analyzed in relation to distress measured using the Edinburgh Postnatal Depression Scale. Principal coordinate analysis and distance-based redundancy analysis assessed variation in functional gut-brain modules. For the U.S. cohort, the Trier Social Stress Test was administered 8 weeks postpartum while collecting salivary cortisol. RESULTS: Principal coordinate analysis identified 4 sample clusters based on the gut-brain modules distinguished by functions such as short-chain fatty acid synthesis and cortisol degradation. While with distance-based redundancy analysis, mental distress subtypes did not significantly contribute to variation in gut-brain modules (p = .085 for Sweden, p = .23 for the U.S.), a U.S. sample cluster distinguished by lower cortisol degradation from another cluster with higher gut microbial cortisol degradation abundance had significantly higher odds of being associated with depression (p = .024). The U.S. sample cluster with lower gut microbial cortisol degradation abundance also had significantly higher cortisol levels after a postpartum social stressor. CONCLUSIONS: Further studies are warranted to investigate the potential for the gut microbiome to serve as biomarkers of gut-brain axis health during pregnancy across disparate populations.