Lycium barbarum polysaccharide attenuates emotional injury of offspring elicited by prenatal chronic stress in rats via regulation of gut microbiota.

Stress during pregnancy is not only detrimental to a woman's own physical and mental health, but can also cause changes in the intrauterine environment and even have an impact on later growth and development, this study was designed to understand the changes of gut microbiota in the maternal and offspring caused by prenatal chronic stress, and to explore the regulatory effect of LBP on gut microbiota, and then to improve the emotional damage caused by prenatal chronic stress in the offspring. A rat model of prenatal chronic stress was made and used LBP to intervene by gavage. Fresh feces of offspring were collected, the concentration of microbial metabolites were tested by ELISA. Illumina MiSeqPE300 sequencing technology was used to determine the sequence of 16S rRNA V3-V4 of microorganisms. On the PND 42, the emotional function of offspring were tested by open-field test (OFT), sucrose preference test (SPT) and tail of suspend test (TST). Results indicated that stress factors increased the plasma corticosterone level of rats during pregnancy and they appeared depressive behaviors. The body weight of offspring during prenatal chronic stress was lower than the control group, and the plasma corticosterone level was increased. Prenatal chronic stress had a significant impact on emotional performance of the offspring on OFT, SPT and TST. Alpha diversity of gut microbiota and microbiota composition in offspring of prenatal chronic stress was attenuated and some relationships existed between these parameters. LBP treatment reduced offspring's plasma corticosterone level and improved their body weight, changed the emotional function, increased the diversity of gut microbiota. Collectively, these findings disclose that prenatal chronic stress not only causes emotional injury on the offspring, but also changes the gut microbiota of the mother and offspring; LBP may regulate the intestinal flora of the mother, then reducing the influence of stress factors on the emotional injury of offspring.

Stress gets into the belly: Early life stress and the gut microbiome.

Research has established that stress "gets under the skin," impacting neuroendocrine and neuroimmune pathways to influence risk for physical and mental health outcomes. These effects can be particularly significant for early life stress (ELS), or adverse childhood experiences (ACEs). In this review, we explore whether stress gets "into the belly," that is, whether psychosocial stress affects the gut microbiome. We review animal and human research utilizing a variety of stress paradigms (acute laboratory stressors, chronic stress, stressful life events, perceived stress, ELS, in utero stress) and their impacts on the gut microbiota, with a particular focus on ELS. We also review data on dietary interventions to moderate impact of stress on the gut microbiome. Our review suggests strong evidence that acute laboratory stress, chronic stress, and ELS affect the gut microbiota in rodents, and growing evidence that perceived stress and ELS may impact the gut microbiota in humans. Emerging data also suggests, particularly in rodents, that dietary interventions such as omega-3 fatty acids and pre- and pro-biotics may buffer against the effects of stress on the gut microbiome, but more research is needed. In sum, growing evidence suggests that stress impacts not only the neuroendocrine and neuroimmune axes, but also the microbiota-gut-brain-axis, providing a pathway by which stress may get "into the belly" to influence health risk.

Anti-depressive effects of Xiaoyaosan, Shugan and Jianpi herbal treatments: Role on the gut microbiome of CUMS rats.

BACKGROUND: Xiaoyaosan (XYS), a classic traditional Chinese medicine (TCM) prescription that contained eight Chinese herbs, has been used for treating depression for thousands of years. Yet, the underlying mechanisms are still unclear, which need to be investigated from various perspectives. Disassembling a prescription is one of the effective approaches to study the effects and the mechanisms of TCM prescriptions. By disassembling the prescription, we can find effective combinations of individual herbs to simplify the scale of a given prescription. Accordingly, herein, XYS was disassembled into Shugan and Jianpi groups. PURPOSE: This study aimed to explore the anti-depressive effects of XYS and its disassembled groups on the digestive system functions and the cecal microbiota of rats. METHODS: XYS was divided into two efficacy groups, i.e., the Shugan (SG) and the Jianpi (JP) groups. A depression model was applied by using the chronic unpredictable mild stress (CUMS) method. Various classic behavioral tests were performed to assess the anti-depressive effects of the XYS, the SG, and the JP. Afterward, the effects of the three groups on the digestive system functions and the cecum microbiota of depression rats were evaluated. On top of this, correlation analyses between behavioral and digestive system function indexes and cecum microbiota were conducted. RESULTS: The XYS, the SG, and the JP had significant callback effects on depressive behaviors and gastrointestinal dysfunctions of CUMS rats. The compositions of the gut bacterial community were variable among the five groups. The community composition of the SG was the most similar to that of NC, followed by the XYS and the JP. At phylum, family, and genus levels, 31 potential microbial biomarkers associated with CUMS were identified. Twenty biomarkers were significantly reversed by the SG while 16 and 11 biomarkers were reversed by the XYS and the JP, respectively. The results of degrees of regulatory effects showed that the SG had the highest efficacy index (EI) than the XYS and the JP. CONCLUSION: Regarding the regulation of cecal microbiota of depression rats, the SG treatment was better than XYS and JP. Therefore, SG could be used individually for the clinical treatment of depression, especially in patients with gastrointestinal and gut microbiota disorders.

A combination of cecum microbiome and metabolome in CUMS depressed rats reveals the antidepressant mechanism of traditional Chinese medicines: A case study of Xiaoyaosan.

ETHNOPHARMACOLOGICAL RELEVANCE: Xiaoyaosan (XYS), a representative and classic prescription in traditional Chinese medicines (TCMs), has been used for thousands of years for treating depression. The anti-depression effect of XYS has been demonstrated both clinically and experimentally. However, it is still unclear that whether XYS could regulate the abnormalities of gut microbiota and metabolites of cecum induced by depression, and in which way. This study aimed to explore the underlying mechanism of the anti-depressant effects of XYS from the perspective of cecal microbiota and metabolites. MATERIALS AND METHODS: Chronic unpredictable mild stress (CUMS)-induced depression-like rats were used as the depression animal model. Various classic behavioral tests were performed to assess the anti-depressant effects of XYS. Additionally, the composition, the richness, and the diversity of the cecum microbiota were assessed by 16S rRNA gene sequencing technology. Besides, the metabolic profiling of cecum samples was analyzed by 1H-NMR metabolomics. Multivariate data analysis was then applied to screen the differential metabolites and to characterize the changes in cecum metabolites. Moreover, a correlation analysis between differential metabolites and crucial microbiota was conducted. RESULTS: XYS significantly improved depressive behaviors and the abnormal diversity of cecum microbiota induced by CUMS. At the phylum level, XYS could significantly increase the abundance of Firmicutes while decrease the abundance of Actinobacteria in depressed rats. XYS significantly regulated the abundances of 9 out of 13 potential microbial biomarkers at the genus level. Cecal metabolomics showed that XYS could also regulate the abnormal levels of alanine, proline, lactate, and valine of depression rats. CONCLUSIONS: This study revealed, for the first time, from the perspectives of microbiota and cecum metabolites, the anti-depression mechanisms of XYS. This study is of significance for not only comprehensively understanding the anti-depression effects and mechanisms of XYS, but also for providing a research approach for revealing the underlying mechanisms of action of TCMs, i.e. to apply a combination of 16S rRNA gene sequencing and metabolomics.

Nutritional interventions for promoting stress resilience: Recent progress using psychosocial stress models of rodents.

Prevention of stress-induced adverse effects is important for animals and humans to maintain their quality of life (QOL). Stress decreases the productivity of farm animals and induces abnormal behaviors, which is one of the major problems in animal welfare. In humans, stress increases the risk of mental illness which adversely impacts QOL. Stress is, thus, a common health problem for both animals and humans, and stress prevention and promotion of stress resilience could improve animal and human health and QOL. Among various stresses, psychosocial stress experienced by individuals is particularly difficult to prevent and it could, thus, prove beneficial to attempt to increase resilience to psychosocial stress. There exist a few critical interventions for promoting such resilience, environmental enrichment being one. However, this review describes recent progress in nutritional interventions that could confer resilience to psychosocial stress. The efficacy of this intervention is studied in the social defeat model mouse, which is a standard model for studying psychosocial stress. Several nutrients were found to rescue stress vulnerability using the models. Furthermore, probiotics and prebiotics became crucial dietary interventions for combating psychosocial stress. Collectively, dietary intake of appropriate nutrients will be more important for maintaining QOL in animals and humans.

Xiaoyaosan slows cancer progression and ameliorates gut dysbiosis in mice with chronic restraint stress and colorectal cancer xenografts.

Depression is a risk factor for colorectal cancer (CRC) progression. Xiaoyaosan (XYS) is a traditional Chinese medicine prescription for treating depression. Our present study aimed to investigate the effect of XYS on chronic restraint stress (CRS) in mice with CRC xenografts and explore its underlying mechanisms. XYS treatment for 21 consecutive days successfully reduced the tumour volume and tumour weight in mice and prolonged the overall survival time. In addition, the intestinal permeability in the XYS group was significantly improved after administration. The 16S rRNA high-throughput sequencing method was used to sequence stool samples to check the structure and changes of gut bacteria. XYS mainly regulated the abundance of Bacteroides, Lactobacillus, Desulfovibrio and Rikenellaceae. Taken together, these results provide direct strong evidence that XYS effectively improves the progression of CRC in CRS-handled mice, and its efficacy is associated with the modulation of gut dysbiosis. The application of XYS can be a novel therapeutic strategy for CRC patients with depression.

Chinese medicine formula Kai-Xin-San ameliorates depression-like behaviours in chronic unpredictable mild stressed mice by regulating gut microbiota-inflammation-stress system.

ETHNOPHARMACOLOGICAL RELEVANCE: Kai-Xin-San (KXS) has been prescribed by TCM doctors for treating psychiatric diseases with the core symptoms of anhedonia, amnesia, and dizziness. According to the symptoms of patients, KXS series formulae are created by varying the compatible ratio of herbs. Today, these formulae are still used in the clinic to treat major depressive disorders. AIM OF THE STUDY: We hoped to evaluate the antidepressant-like effect of Kai-Xin-San via regulation of the gut-brain axis. MATERIALS AND METHODS: Standardized extracts of three representative compatible ratios of KXS had been prepared, and quality control of the extracts was performed by HPLC-MS/MS. Chronic unpredictable mild stress (CUMS)-induced depression-like mice were used as the depression animal model. After KXS treatment, the antidepressant-like effects of KXS were assessed by behavioural tests. The gut microbiota compositions in the faeces were determined by 16S rRNA sequencing technology. The levels of LPS, pro-inflammatory cytokines and HPA-axis-related hormones were measured by ELISA kits, and the expression of barrier proteins in the small intestines and prefrontal cortex were determined by Western blot analysis. Furthermore, antibiotics were used to determine the correlation between KXS exerting an antidepressant-like effect and regulating the gut-brain axis. RESULTS: KXS alleviated depression-like behaviours in CUMS-exposed mice. Furthermore, these parameters were also found to be changed after KXS treatment. Alteration of the gut microbiota composition were found in the small intestines. A decrease in the LPS and the pro-inflammatory cytokines were found in both the small intestine and brain. An increase in the tight junction proteins was found in the gut epithelium barrier and the blood-brain barrier. A decrease in the stress-related hormones was found in the central nervous system. Furthermore, antibiotic treatment attenuated the antidepressant-like effect of KXS in CUMS-exposed mice. CONCLUSIONS: KXS exerted an antidepressant-like effect regulating the gut-brain axis, which included gut micro-environment modification, suppression of neuronal inflammation in the brain and inhibition of HPA axis activation in CUMS-induced depression-like mice.

Stress and the brain-gut axis in functional and chronic-inflammatory gastrointestinal diseases: A transdisciplinary challenge.

The broad role of stress in the brain-gut axis is widely acknowledged, with implications for multiple prevalent health conditions that are characterized by chronic gastrointestinal symptoms. These include the functional gastrointestinal disorders (FGID), such as irritable bowel syndrome and functional dyspepsia, as well as inflammatory bowel diseases (IBD) like ulcerative colitis and Crohn's disease. Although the afferent and efferent pathways linking the gut and the brain are modulated by stress, the fields of neurogastroenterology and psychoneuroendocrinology (PNE)/ psychoneuroimmunology (PNI) remain only loosely connected. We aim to contribute to bringing these fields closer together by drawing attention to a fascinating, evolving research area, targeting an audience with a strong interest in the role of stress in health and disease. To this end, this review introduces the concept of the brain-gut axis and its major pathways, and provides a brief introduction to epidemiological and clinical aspects of FGIDs and IBD. From an interdisciplinary PNE/PNI perspective, we then detail current knowledge regarding the role of chronic and acute stress in the pathophysiology of FGID and IBD. We provide an overview of evidence regarding non-pharmacological treatment approaches that target central or peripheral stress mechanisms, and conclude with future directions, particularly those arising from recent advances in the neurosciences and discoveries surrounding the gut microbiota.

Impact of traditional Chinese medicine treatment on chronic unpredictable mild stress-induced depression-like behaviors: intestinal microbiota and gut microbiome function.

Gut microbiota dysbiosis is a recognized contributing factor to many noncommunicable diseases, but more evidence is still needed to illustrate its causative impact on mental and brain health disorders and mechanism(s) for targeted mitigation. Traditional Chinese Medicine (TCM) has been used in the management of neuropsychiatric diseases for many years in China. In this study, a randomized, controlled trial was conducted to examine the impact of stress on gut microbiota dysbiosis and depression, and TCM in alleviating the damage using Chronic Unpredictable Mild Stress (CUMS) rats, a well-established rodent model for depression. The behaviors of rats and the profiles of the fecal microbiota were assessed by an array of behavioral tests and 16S rRNA gene sequencing, and the intestinal microbial function was assessed by shotgun sequencing-based metagenomic analysis of microbial DNA from fecal samples. Data on brain targeted metabolites by liquid chromatography-mass spectrometry (LC-MS) were also discussed. Depressive and anxiety-like behaviors and changes in the fecal microbiota profile were observed in CUMS rats, which were then significantly reversed in CUMS rats that received TCM. Specifically, TCM treatment reduced the levels of Firmicutes, and Ruminococcus, and increased the abundance of Bacteroidetes and Roseburia, reportedly being associated with relieving psychiatric disorders. Furthermore, the levels of brain metabolites perturbed by CUMS were reversed by TCM treatment, and Spearman's correlation analysis illustrated strong correlation between brain metabolites and perturbed fecal microbiota genera. Finally, the fecal microbiome of CUMS rats was characterized by alterations in amino acid metabolism and evaluation of bile acid biosynthesis, and TCM-treated rats showed elevation of cysteine and methionine metabolism. Overall, these results indicated that administration of the TCM may mitigate CUMS-induced depression-behaviors, and it is correlated with reversing CUMS-induced intestinal microbiota dysbiosis; evidence also supported related changes in brain metabolites. These findings set up the foundation to further reveal the exact causal relationship among the TCM formula, host responses, gut microbiota dysbiosis and the levels of brain metabolites, and enabled scientific interpretation of the therapeutic function of the TCM.

Xiaoyaosan improves depressive-like behavior in rats with chronic immobilization stress through modulation of the gut microbiota.

Depression has become the leading cause of disability worldwide and a growing public health problem in China. In addition, intestinal flora may be associated with depression. This study investigated the effect of the decoction Xiaoyaosan (XYS) against depressive behavior through the regulation of intestinal flora. Fifty-two healthy male Sprague-Dawley rats were randomly divided into four groups (i.e., control, model, XYS, and fluoxetine). The latter three groups were subjected to 21 days of chronic restraint stress to produce the stress depression model. Rats in the XYS and fluoxetine groups received intragastric administration of XYS and fluoxetine, respectively. The behavioral changes of the rats were observed after 21 days. Stool specimens were sequenced using the 16S rDNA high-throughput method to detect the structure and changes in intestinal flora. There was no difference observed in alpha diversity among the groups. At the phylum level, XYS regulated the abundance of Bacteroidetes, Proteobacteria, Firmicutes, Chloroflexi, and Planctomycetes. At the genus level, XYS reduced the abundance of the Prevotellaceae_Ga6A1_group, Prevotellaceae_UCG-001, and Desulfovibrio. On the contrary, it increased the abundance of the Ruminococcaceae family to improve depression-like behavior. The mechanism involved in this process may be related to short-chain fatty acids, lipopolysaccharides, and intestinal inflammation.

Childhood adversity impact on gut microbiota and inflammatory response to stress during pregnancy.

BACKGROUND: Adverse childhood experiences (ACEs), such as abuse or chronic stress, program an exaggerated adult inflammatory response to stress. Emerging rodent research suggests that the gut microbiome may be a key mediator in the association between early life stress and dysregulated glucocorticoid-immune response. However, ACE impact on inflammatory response to stress, or on the gut microbiome, have not been studied in human pregnancy, when inflammation increases risk of poor outcomes. The aim of this study was to assess the relationships among ACE, the gut microbiome, and cytokine response to stress in pregnant women. METHODS: Physically and psychiatrically healthy adult pregnant women completed the Adverse Childhood Experiences Questionnaire (ACE-Q) and gave a single stool sample between 20 and 26 weeks gestation. Stool DNA was isolated and 16S sequencing was performed. Three 24-hour food recalls were administered to assess dietary nutrient intake. A subset of women completed the Trier Social Stress Test (TSST) at 22-34 weeks gestation; plasma interleukin-6 (IL-6), interleukin-1ß (IL-1ß), high sensitivity C-reactive protein (hsCRP), tumor necrosis factor α (TNF-α), and cortisol were measured at four timepoints pre and post stressor, and area under the curve (AUC) was calculated. RESULTS: Forty-eight women completed the ACE-Q and provided stool; 19 women completed the TSST. Women reporting 2 or more ACEs (high ACE) had greater differential abundance of gut Prevotella than low ACE participants (q = 5.7 × 10^-13). Abundance of several gut taxa were significantly associated with cortisol, IL-6, TNF-α and CRP AUCs regardless of ACE status. IL-6 response to stress was buffered among high ACE women with high intake of docosahexaenoic acid (DHA) (p = 0.03) and eicosapentaenoic acid (EPA) (p = 0.05). DISCUSSION: Our findings suggest that multiple childhood adversities are associated with changes in gut microbiota composition during pregnancy, and such changes may contribute to altered inflammatory and glucocorticoid response to stress. While preliminary, this is the first study to demonstrate an association between gut microbiota and acute glucocorticoid-immune response to stress in a clinical sample. Finally, exploratory analyses suggested that high ACE women with high dietary intake of ω-3 polyunsaturated fatty acids (PUFAs) had a dampened inflammatory response to acute stress, suggesting potentially protective effects of ω-3s in this high-risk population. Given the adverse effects of inflammation on pregnancy and the developing fetus, mechanisms by which childhood adversity influence the gut-brain axis and potential protective factors such as diet should be further explored.

Intestinal Microbiome in Irritable Bowel Syndrome before and after Gut-Directed Hypnotherapy.

Irritable bowel syndrome (IBS) is a disorder with brain-gut-microbiome alterations. Gut-directed hypnotherapy (GHT) has been shown to improve quality of life and symptoms in IBS. This therapy targets psychological coping, central nervous processing and brain-gut interaction. Studies have also demonstrated effects of hypnosis on intestinal transit and the mucosal immune system. So far, no study has examined the effect of GHT on the intestinal microbiome. This study aimed at examining microbial composition, IBS symptoms, and psychological distress before and after GHT. METHODS: Fecal samples were collected from 38 IBS patients (Rome-III criteria, mean age 44 years, 27 female, 11 male, 22 diarrhea-dominant, 12 alternating-type and 4 constipation-dominant IBS) before and after 10 weekly group sessions of GHT. Assessments in psychological (perceived stress, PSQ; psychological distress, HADS-D; quality of life, visual analogue scales) and IBS symptom-related variables (IBS severity, IBS-SSS; single symptoms, visual analogue scales) were performed with validated questionnaires. Fecal samples underwent microbial 16S rRNA analyses (regions V1⁻2). RESULTS: Microbial alpha diversity was stable before and after GHT (chao1 2591 ± 548 vs. 2581 ± 539, p = 0.92). No significant differences were found in relative bacterial abundances but trends of reduced abundance of Lachnospiraceae 32.18 (4.14⁻39.89) Median (Q1⁻Q3) vs. 28.11 (22.85; 35.55) and Firmicutes: Bacteroidetes ratio after GHT were observable. Significant reductions in symptom severity (323 (266⁻371) vs. 264 (191⁻331), p = 0.001) and psychological distress 17.0 (12.6⁻21.8) vs. 12.0 (8.3⁻18.0), p = 0.001, and increased well-being were found after GHT. Adequate relief after therapy was reported by 32 (84%) patients. CONCLUSION: Reductions in IBS symptoms and psychological burden were observed after gut-directed hypnotherapy, but only small changes were found in intestinal microbiota composition. The findings suggest that hypnosis may act by central nervous impact and other factors largely independent from microbiota composition modulating the brain-gut axis, possibly alterations in vagus nerve functioning and microbiota metabolism.

Short-chain fatty acids: microbial metabolites that alleviate stress-induced brain-gut axis alterations.

KEY POINTS: Chronic (psychosocial) stress changes gut microbiota composition, as well as inducing behavioural and physiological deficits. The microbial metabolites short-chain fatty acids (SCFAs) have been implicated in gastrointestinal functional, (neuro)immune regulation and host metabolism, but their role in stress-induced behavioural and physiological alterations is poorly understood. Administration of SCFAs to mice undergoing psychosocial stress alleviates enduring alterations in anhedonia and heightened stress-responsiveness, as well as stress-induced increases in intestinal permeability. In contrast, chronic stress-induced alterations in body weight gain, faecal SCFAs and the gene expression of the SCFA receptors FFAR2 and FFAR3 remained unaffected by SCFA supplementation. These results present novel insights into mechanisms underpinning the influence of the gut microbiota on brain homeostasis, behaviour and host metabolism, informing the development of microbiota-targeted therapies for stress-related disorders. ABSTRACT: There is a growing recognition of the involvement of the gastrointestinal microbiota in the regulation of physiology and behaviour. Microbiota-derived metabolites play a central role in the communication between microbes and their host, with short-chain fatty acids (SCFAs) being perhaps the most studied. SCFAs are primarily derived from fermentation of dietary fibres and play a pivotal role in host gut, metabolic and immune function. All these factors have previously been demonstrated to be adversely affected by stress. Therefore, we sought to assess whether SCFA supplementation could counteract the enduring effects of chronic psychosocial stress. C57BL/6J male mice received oral supplementation of a mixture of the three principle SCFAs (acetate, propionate and butyrate). One week later, mice underwent 3 weeks of repeated psychosocial stress, followed by a comprehensive behavioural analysis. Finally, plasma corticosterone, faecal SCFAs and caecal microbiota composition were assessed. SCFA treatment alleviated psychosocial stress-induced alterations in reward-seeking behaviour, and increased responsiveness to an acute stressor and in vivo intestinal permeability. In addition, SCFAs exhibited behavioural test-specific antidepressant and anxiolytic effects, which were not present when mice had also undergone psychosocial stress. Stress-induced increases in body weight gain, faecal SCFAs and the colonic gene expression of the SCFA receptors free fatty acid receptors 2 and 3 remained unaffected by SCFA supplementation. Moreover, there were no collateral effects on caecal microbiota composition. Taken together, these data show that SCFA supplementation alleviates selective and enduring alterations induced by repeated psychosocial stress and these data may inform future research into microbiota-targeted therapies for stress-related disorders.

Psychological Stress, Immunity, and the Effects on Indigenous Microflora.

Psychological stress is an intrinsic part of life that affects all organs of the body through direct nervous system innervation and the release of neuroendocrine hormones. The field of PsychoNeuroImmunology (PNI) has clearly demonstrated that the physiological response to psychological stressors can dramatically impact the functioning of the immune system, thus identifying one way in which susceptibility to or severity of diseases are exacerbated during stressful periods. This chapter describes research at the interface between the fields of PNI and Microbial Endocrinology to demonstrate that natural barrier defenses, such as those provided by the commensal microflora, can be disrupted by exposure to psychological stressors. These stress effects are evident in the development of the intestinal microflora in animals born from stressful pregnancy conditions, and in older animals with fully developed microbial populations. Moreover, data are presented demonstrating that exposure to different types of stressors results in the translocation of microflora from cutaneous and mucosal surfaces into regional lymph nodes. When considered together, a scenario emerges in which psychological stressors induce a neuroendocrine response that has the potential to directly or indirectly affect commensal microflora populations, the integrity of barrier defenses, and the internalization of microbes. Finally, a hypothesis is put forth in which stressor-induced alterations of the microflora contribute to the observed stressor-induced increases in inflammatory markers in the absence of overt infection.

N-3 Polyunsaturated Fatty Acids (PUFAs) Reverse the Impact of Early-Life Stress on the Gut Microbiota.

BACKGROUND: Early life stress is a risk factor for many psychiatric disorders ranging from depression to anxiety. Stress, especially during early life, can induce dysbiosis in the gut microbiota, the key modulators of the bidirectional signalling pathways in the gut-brain axis that underline several neurodevelopmental and psychiatric disorders. Despite their critical role in the development and function of the central nervous system, the effect of n-3 polyunsaturated fatty acids (n-3 PUFAs) on the regulation of gut-microbiota in early-life stress has not been explored. METHODS AND RESULTS: Here, we show that long-term supplementation of eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) (80% EPA, 20% DHA) n-3 PUFAs mixture could restore the disturbed gut-microbiota composition of maternally separated (MS) female rats. Sprague-Dawley female rats were subjected to an early-life stress, maternal separation procedure from postnatal days 2 to 12. Non-separated (NS) and MS rats were administered saline, EPA/DHA 0.4 g/kg/day or EPA/DHA 1 g/kg/day, respectively. Analysis of the gut microbiota in adult rats revealed that EPA/DHA changes composition in the MS, and to a lesser extent the NS rats, and was associated with attenuation of the corticosterone response to acute stress. CONCLUSIONS: In conclusion, EPA/DHA intervention alters the gut microbiota composition of both neurodevelopmentally normal and early-life stressed animals. This study offers insights into the interaction between n-3 PUFAs and gut microbes, which may play an important role in advancing our understanding of disorders of mood and cognitive functioning, such as anxiety and depression.

[Condition of protective intestinal microbiota populations under stress exposure in rats received different diets with bioactive food components].

The evaluation of the levels of major colon microbiota populations (lactobacilli, bifidobacteria, enterobacteria) was carried out in two 15-days experiments on Wistar rats, exposed to stress factor (electric shock) and fed with different diets with the addition of biologic active micronutrients [extract from the leaves of Serratula coronata L. and Enzymatic hydrolyzate of the mussels meat (EHMM)]. In the first experiment animals were fed with a common vivarium diet. In the experimental group the water extract from leaves of Serratula coronata L. as a phytoecdysteroid source (5 mg per 1 kg body weight) was added to water. In the second experiment rats received balanced semisynthetic diet. In the diet of the experimental group the part of the protein (casein) was replaced by the peptides from EHMM. During the experiment the animal body weight was measured. On the 14th day of the experiment the animals were subjected to stress stimulation [electrodermal stimulation on paws (electric current 0.4 mA for 8 seconds)]. On the last day of the experiment the animals were euthanized by decapitation and micro-ecological research of protective microbiota populations in the cecal contents was carried out. The relative body weight increase was recorded in both experiments. In the second experiment in animals receiving EHMM this index (68.2 ± 3.0%) was considerably higher than in the control group and in the experimental group receiving no EHMM (57.2 ± 4.0 and 59.7 ± 2.8% respectively). The results of the microecological study showed different effect of diets with biologically active micronutrients on the population levels of lactobacilli. In the experiment with common vivarium diet no significant changes of the levels of the studied colon microbiota populations had been recorded in the rats of control group compared with rats of experimental group, exposed to stress factor but received no extract from Serratula coronata L. The decrease of the levels of lactobacilli by the end of the experiment was observed in the experimental group of rats received water extract from the leaves of Serratula coronata L (content of lactobacilli 7.76 ± 0.17 lg CFU/g) compared to those in control group and experimental group of rats received no extract (8.4 ± 0.09 and 8.69 ± 0.07 lg CFU/g respectively). Feeding with the balanced semisynthetic diet with the addition of EHMM or without it had a positive effect on the levels of lactobacilli and their balance with the aerobic component of the Enterobacteriaceae. There was a trend toward increased levels of lactic acid bacteria in the experimental group received EHMM (9.16 ± 0.12 lg CFU/g) compared with the contents in the control group and in the experimental group exposed to stress factor without adding EHMM in the diet (8.74 ± 0.34 and 8.79 ± 0.23 lg CFU/g, respectively). The conclusion about the positive (protective) effect of a semisynthetic diet enriched with peptides from EHMM was made based on the comparison of indicators that reflect the status of non-specific resistance of the organism: the integral criterion of weight gain and the levels of major colon microbiota populations of laboratory animals.

Stress and the periodontal diseases: growth responses of periodontal bacteria to Escherichia coli stress-associated autoinducer and exogenous Fe.

Psychological stress is known to increase the circulating levels of the catecholamine hormones noradrenaline and adrenaline, which have been shown to influence the growth of a large number of bacterial species by acting in a siderophore-like manner or by inducing the production of novel autoinducers of growth. As we have previously demonstrated that periodontal organisms display differing growth responses to noradrenaline and adrenaline, the aim of this study was to determine whether these growth effects were based upon either siderophore-like or autoinducer mechanisms. Initial inocula of 43 microbial organisms normally found within the subgingival biofilm were established under anaerobic conditions (35 degrees C). Each strain was re-inoculated into a serum-based minimal medium and growth was assessed by optical density (OD(600 nm)) with test and control cultures performed in triplicate. Test cultures were supplemented with either 50 mum ferric nitrate or a previously described Escherichia coli autoinducer of growth. Significant growth effects for supplementation with ferric nitrate (13 species responding positively) and E. coli autoinducer (24 species responding positively) were observed, with differences in growth response within bacterial species and within microbial complexes. When data for all organisms were compared with published responses to catecholamines there were only weak correlations with Fe (r = 0.28) and E. coli autoinducer (r = 0.34) responses. However, large positive responses (> 25% increase) to free Fe and/or E. coli autoinducer were significantly more prevalent in the group of organisms (n = 12) known to exhibit similar responses to catecholamine hormones (P < 0.01; chi2 = 4.56). The results support the view that catecholamines may exert their effects on subgingival organisms by initiating autoinducer production, or simply by acting in a siderophore-like manner, scavenging bound iron from the local environment. It is possible that autoinducer mechanisms may play an important role in the response of oral microorganisms to stress hormones, thereby contributing to the clinical course of stress-associated periodontal diseases.

The causes of intestinal dysbiosis: a review.

Alterations in the bowel flora and its activities are now believed to be contributing factors to many chronic and degenerative diseases. Irritable bowel syndrome, inflammatory bowel disease, rheumatoid arthritis, and ankylosing spondylitis have all been linked to alterations in the intestinal microflora. The intestinal dysbiosis hypothesis suggests a number of factors associated with modern Western living have a detrimental impact on the microflora of the gastrointestinal tract. Factors such as antibiotics, psychological and physical stress, and certain dietary components have been found to contribute to intestinal dysbiosis. If these causes can be eliminated or at least attenuated then treatments aimed at manipulating the microflora may be more successful