Administration of Lactobacillus helveticus NS8 improves behavioral, cognitive, and biochemical aberrations caused by chronic restraint stress

Effects of orally administered cortisol and norepinephrine on weanling piglet gut microbial populations and Salmonella passage

Stress and anxiety have been associated with changes in the microbiota of the gut and ultimately diminished resistance to pathogens. The objective of this study was to observe intestinal microbiota and susceptibility to Salmonella associated with stress hormones, cortisol (CORT), and norepinephrine (NE), in piglets. At weaning, 90 piglets (15 for a Salmonella challenge) were trained to take the carrier (apple juice) orally. At 2 wk after weaning, pens of piglets were assigned randomly to 1 of 3 treatments: control (CNT), NE, or CORT. Blood samples were collected prior to treatment, then piglets were dosed orally with treatments twice on day 0; at 0800 and 1600 h. Control piglets were administered 6.1 mL of the carrier only, NE pigs were administered 40 mg/mL of NE-bitartrate salt dissolved in the carrier, and CORT pigs were administered 12 mg/mL of hydrocortisone acetate dissolved in the carrier. Jugular blood samples were collected prior to necropsies (n = 5/treatment) at 0800 and 1600 h on day 1, and at 0800 h on days 2, 7, and 14 after treatments were started. A subset of pigs were subjected to a 24-h Salmonella challenge. Jejunal and ileal tissues and jejunal, ileal, cecal, and rectal contents were collected and colonies were counted. Microbial data and blood samples were analyzed using mixed models with fixed effects of treatment and day. Cortisol-treated piglets exhibited a spike in plasma CORT concentrations at 0800 h day 1 (P = 0.001) accompanied by greater concentrations of cecal Escherichia coli (P < 0.05) and a shift in intestinal environment to favor coliforms on day 2 (P < 0.05). Salmonella concentrations from rectal contents tended (P = 0.07) to be suppressed by CORT. Lactic acid-producing bacteria rectal concentrations were greater (P = 0.03) in CORT pigs on 0800 h on day 1 then NE pigs and tended to be greater than CNT (P = 0.09) and were greater on day 14 for both CNT (P = 0.003) and NE (P = 0.02). Norepinephrine spiked in NE piglets at 0800 h on day 1 (P = 0.001), 1600 h day 1 (P = 0.004), through day 2 (P = 0.04). Intestinal environment of NE pigs shifted to favor ileal anaerobes (P ≤ 0.05) and facultative anaerobes (E. coli; P = 0.01) compared to CNT. However, Salmonella concentrations in rectal contents were suppressed by NE compared to CNT (P = 0.05). Oral administration of NE and CORT had the desired effect of increasing concentrations of stress hormones and resulted in microbiome shifts throughout the intestines.

Antidepressant-Like and Neuroprotective Effects of Ethanol Extract from the Root Bark of Hibiscus syriacus L

Hibiscus syriacus L. (Malvaceae) is an important ornamental shrub in horticulture and has been widely used as a medical material in Asia. The aim of this study was to assess the antidepressant and neuroprotective effects of a root bark extract of H. syriacus (HSR) and to investigate the underlying molecular mechanisms. Using an animal model of restraint stress, we investigated the effects of HSR on depressive-like behaviors and on the expression levels of serotonin, corticosterone, and neurotrophic factors in the brain. The mice were exposed to restraint stress for 2 h per day over a period of 3 weeks and orally treated with HSR (100, 200, or 400 mg/kg/day). We also examined the neuroprotective effect of HSR using corticosterone-treated human neuroblastoma SK-N-SH cells. The cells were incubated with the extract for 24 h, followed by corticosterone stimulation for 1 h, and then cell viability assay, cellular ATP assay, mitochondrial membrane potential (MMP) assay, cellular reactive oxygen species (ROS) assay, and western blotting were used to investigate the neuroprotective effects of HSR. Administration of HSR not only reduced the immobility times of the restraint-stressed mice in the forced swimming and tail suspension tests, but also significantly increased sucrose preference in the sucrose preference test. In addition, HSR significantly reduced the plasma levels of corticosterone and increased the brain levels of serotonin. The extract also increased the phosphorylation level of cyclic AMP response element-binding (CREB) protein and the expression level of brain-derived neurotrophic factor (BDNF). The in vitro assays showed that HSR pretreatment increased cell viability and ATP levels, recovered MMP, decreased ROS levels, and increased the expression of CREB and BDNF in corticosterone-induced neurotoxicity. Taken together, our data suggest that HSR may have the potential to control neuronal cell damage and depressive behaviors caused by chronic stress.

Oral Probiotics Ameliorate the Behavioral Deficits Induced by Chronic Mild Stress in Mice via the Gut Microbiota-Inflammation Axis

In recent years, a burgeoning body of research has revealed links between depression and the gut microbiota, leading to the therapeutic use of probiotics for stress-related disorders. In this study, we explored the potential antidepressant efficacy of a multi-strain probiotics treatment (Lactobacillus helveticus R0052, Lactobacillus plantarum R1012, and Bifidobacterium longum R0175) in a chronic mild stress (CMS) mouse model of depression and determined its probable mechanism of action. Our findings revealed that mice subjected to CMS exhibited anxiety- and depressive-like behaviors in the sucrose preference test, elevated plus maze, and forced swim test, along with increased interferon-γ, tumor necrosis factor-α, and indoleamine 2,3-dioxygenase-1 levels in the hippocampus. Moreover, the microbiota distinctly changed from the non-stress group and was characterized by highly diverse bacterial communities associated with significant reductions in Lactobacillus species. Probiotics attenuated CMS-induced anxiety- and depressive-like behaviors, significantly increased Lactobacillus abundance, and reversed the CMS-induced immune changes in the hippocampus. Thus, the possible mechanism involved in the antidepressant-like activity of probiotics is correlated with Lactobacillus species via the gut microbiota-inflammation-brain axis.

The Gut-Microglia Connection: Implications for Central Nervous System Diseases

The importance of the gut microbiome in central nervous system (CNS) diseases has long been recognized; however, research into this connection is limited, in part, owing to a lack of convincing mechanisms because the brain is a distant target of the gut. Previous studies on the brain revealed that most of the CNS diseases affected by the gut microbiome are closely associated with microglial dysfunction. Microglia, the major CNS-resident macrophages, are crucial for the immune response of the CNS against infection and injury, as well as for brain development and function. However, the current understanding of the mechanisms controlling the maturation and function of microglia is obscure, especially regarding the extrinsic factors affecting microglial function during the developmental process. The gut microflora has been shown to significantly influence microglia from before birth until adulthood, and the metabolites generated by the microbiota regulate the inflammation response mediated by microglia in the CNS; this inspired our hypothesis that microglia act as a critical mediator between the gut microbiome and CNS diseases. Herein, we highlight and discuss current findings that show the influence of host microbiome, as a crucial extrinsic factor, on microglia within the CNS. In addition, we summarize the CNS diseases associated with both the host microbiome and microglia and explore the potential pathways by which the gut bacteria influence the pathogenesis of CNS diseases. Our work is thus a comprehensive theoretical foundation for studies on the gut-microglia connection in the development of CNS diseases; and provides great potential for researchers to target pathways associated with the gut-microglia connection and overcome CNS diseases.

Antidepressant Effects of Rosemary Extracts Associate With Anti-inflammatory Effect and Rebalance of Gut Microbiota

It is currently believed that inflammation acts as a central part in the pathophysiology of depression. Rosemary extracts (RE), the crucial active constituents extracted from Rosmarinus officinalis Linn, have drawn wide concerns because of their potential for anti-inflammatory effects. However, no study has highlighted the antidepressant effects of RE on chronic restraint stress (CRS) mice, and the inflammatory mechanisms related to gut microbiome have not yet been elucidated. This study showed that depressive-like behaviors, gut microbiota dysbiosis, and activation of inflammatory reactions in the hippocampus and serum of CRS mice, as well as activation of inflammatory reactions in BV-2 microglia cells induced by lipopolysaccharide (LPS), could be attenuated by RE. We found that the pretreatment with RE increased the time in the center of open field test (OFT), and decreased immobility duration in tail suspension test (TST) as well as forced swimming test (FST). Furthermore, RE enhanced the sequences proportion of Lactobacillus and Firmicutes, and reduced the sequences proportion of Bacteroidetes and Proteobacteria in feces. Moreover, RE obviously suppressed protein expression of IL-1β, TNF-α, p-NF-κ B p65 and Iba1 in hippocampus, and elevated BDNF as well as p-AKT/AKT expression. Importantly, pre-incubation with RE protected microglia by alleviating protein expression of IL-1β, TNF-α and p-NF-κ B p65 induced by LPS. Additionally, RE downregulated the level of IL-1β and TNF-α in serum. In conclusion, this study showed the antidepressant effects of RE are mediated by anti-inflammatory effects in hippocampus, serum and BV-2 microglia as well as rebalancing gut microbiota.

The microbial metabolite indole-3-propionic acid improves glucose metabolism in rats, but does not affect behaviour

CONTEXT

We have previously shown that an antidepressant-like effect of probiotics in rats was associated with a higher plasma level of the microbial tryptophan metabolite indole-3-propionic acid (IPA).

OBJECTIVE

We therefore wanted to study the isolated effect of IPA on behaviour and glucose metabolism in rats.

METHODS

Male Sprague-Dawley rats were fed control or IPA-enriched diet for six weeks (n = 12 per group) and assessed in the elevated plus maze, open field and forced swim test. Blood glucose, metabolic hormones and the white blood cell (WBC) composition were analysed.

RESULTS

IPA (mean intake 27.3 mg/kg/day) significantly lowered fasting blood glucose level by 0.42 mM (95% CI 0.11-0.73). Similarly, fasting plasma insulin levels and the homeostatic model assessment (HOMA) index of insulin resistance were reduced, whereas plasma metabolic hormones, behaviour and WBC composition remained unaffected by IPA.

CONCLUSIONS

Our findings highlight IPA as a promising candidate for treatment of metabolic disorders associated with insulin resistance.

Immunization with Mycobacterium vaccae induces an anti-inflammatory milieu in the CNS: Attenuation of stress-induced microglial priming, alarmins and anxiety-like behavior

Exposure to stressors induces anxiety- and depressive-like behaviors, which are mediated, in part, by neuroinflammatory processes. Recent findings demonstrate that treatment with the immunoregulatory and anti-inflammatory bacterium, Mycobacterium vaccae (M. vaccae), attenuates stress-induced exaggeration of peripheral inflammation and stress-induced anxiety-like behavioral responses. However, the effects of M. vaccae on neuroimmune processes have largely been unexplored. In the present study, we examined the effect of M. vaccae NCTC11659 on neuroimmune regulation, stress-induced neuroinflammatory processes and anxiety-like behavior. Adult male rats were immunized 3× with a heat-killed preparation of M. vaccae (0.1 mg, s.c.) or vehicle. M. vaccae induced an anti-inflammatory immunophenotype in hippocampus (increased interleukin (Il)4, Cd200r1, and Mrc1 mRNA expression) and increased IL4 protein 8 d after the last immunization. Central administration of recombinant IL4 recapitulated the effects of M. vaccae on Cd200r1 and Mrc1 mRNA expression. M. vaccae reduced basal levels of genes (Nlrp3 and Nfkbia) involved in microglial priming; thus, we explored the effects of M. vaccae on stress-induced hippocampal microglial priming and HMGB1, which mediates priming. We found that M. vaccae blocked stress-induced decreases in Cd200r1, increases in the alarmin HMGB1, and priming of the microglial response to immune challenge. Furthermore, M. vaccae prevented stress-induced increases in anxiety-like behavior. The present findings suggest that M. vaccae enhances immunomodulation in the CNS and mitigates the neuroinflammatory and behavioral effects of stress, which may underpin its capacity to impart a stress resilient phenotype.

Moody microbiome: Challenges and chances

Growing evidence link gut microbiome to the development and maturation of the central nervous system, which are regulated by microbiota potentially through stress response, neurotransmitter, neuroimmune, and endocrine pathways. The dysfunction of such microbiota-gut-brain axis is implicated in neuropsychiatric disorders, depression, and other stress-related conditions. Using affective disorders as our primary outcomes, we inspect the current evidence of microbiota studies mainly in human clinical samples. Additionally, to restore microbiome equilibrium in bacteria diversity and abundance might represent a novel strategy to prevent or treat mood symptoms. We reviewed findings from clinical trials regarding efficacy of probiotics supplement with or without antidepressant treatment, and adjuvant antimicrobiotics treatment. In microbiota studies, the considerations of host-microbiota interaction and bacteria-bacteria interaction are discussed. In conclusion, the roles of microbiota in depression and mania state are not fully elucidated. One of the challenges is to find reliable targets for functional analyses and experiments. Notwithstanding some inconsistencies and methodological limitations across studies, results from recent clinical trials support for the beneficial effects of probiotics on alleviating depressive symptoms and increasing well-beings. Moreover, modifying the composition of gut microbiota via antibiotics can be a viable adjuvant treatment option for individuals with depressive symptoms.

Mechanisms underlying the effects of stress on tumorigenesis and metastasis (Review)

Stress is one of the fundamental survival mechanisms in nature. Although chronic or long-lasting stress can be detrimental to health, acute or short-term stress can have health benefits. The aim of the present review was to address the complexity and significance of stress in tumorigenesis. The review covers an evaluation of previously used and reported experimental animal models of stress, as well as the effects of stress on the neuroendocrine system, immune function, gut microbiota, and inflammation and multidrug resistance, all of which are closely associated with cancer occurrence, progression and treatment. The review concludes that understanding the efficacy of stress management (prevention and rehabilitation) is crucial to the development of comprehensive and individualized strategies for cancer prevention and treatment.

The Gut Microbiota and Dysbiosis in Autism Spectrum Disorders

PURPOSE OF REVIEW

There is a growing body of evidence indicating the gut microbiota influence neurodevelopment and behavior. The purposes of this review are to provide an overview of studies analyzing the microbiota and their metabolites in autism spectrum disorders (ASD) and to discuss the possible mechanisms of action involved in microbial influence on the brain and behavior.

RECENT FINDINGS

The microbiota-gut-brain (MGB) axis has been extensively studied in animal models, and it is clear that alterations in the composition of microbiota alter neurological and behavioral outcomes. However, findings in human studies are less abundant. Although there are several studies so far showing altered microbiota (dysbiosis) in ASD, the results are heterogeneous and often contradictory. Intervention studies such as fecal microbiota transplant therapies show promise and lend credence to the involvement of the microbiota in ASD. A role for the microbiota in ASD is likely; however, further studies elucidating microbial or metabolomic signatures and mechanisms of action are needed. Future research should focus on intervention studies that can identify specific metabolites and immune mediators that improve with treatment to help identify etiologies and pathological mechanisms of ASD.

Ginsenoside Rb1 exerts neuroprotective effects through regulation of Lactobacillus helveticus abundance and GABAA receptor expression

Background

Ginsenoside Rb1 (Rb1), one of the most abundant protopanaxadiol-type ginsenosides, exerts excellent neuroprotective effects even though it has low intracephalic exposure.

Purpose

The present study aimed to elucidate the apparent contradiction between the pharmacokinetics and pharmacodynamics of Rb1 by studying the mechanisms underlying neuroprotective effects of Rb1 based on regulation of microflora.

Methods

A pseudo germ-free (PGF) rat model was established, and neuroprotective effects of Rb1 were compared between conventional and PGF rats. The relative abundances of common probiotics were quantified to reveal the authentic probiotics that dominate in the neuroprotection of Rb1. The expressions of the gamma-aminobutyric acid (GABA) receptors, including GABAA receptors (α2, β2, and γ2) and GABAB receptors (1b and 2), in the normal, ischemia/reperfusion (I/R), and I/R+Rb1 rat hippocampus and striatum were assessed to reveal the neuroprotective mechanism of Rb1.

Results

The results showed that microbiota plays a key role in neuroprotection of Rb1. The relative abundance of Lactobacillus helveticus (Lac.H) increased 15.26 fold after pretreatment with Rb1. I/R surgery induced effects on infarct size, neurological deficit score, and proinflammatory cytokines (IL-1β, IL-6, and TNF-α) were prevented by colonizing the rat gastrointestinal tract with Lac.H (1 × 10⁹ CFU) by gavage 15 d before I/R surgery. Both Rb1 and Lac.H upregulated expression of GABA receptors in I/R rats. Coadministration of a GABA_A receptor antagonist significantly attenuated neuroprotective effects of Rb1 and Lac.H.

Conclusion

In sum, Rb1 exerts neuroprotective effects by regulating Lac.H and GABA receptors rather than through direct distribution to the target sites.

The Microbiota-Gut-Brain Axis in Neuropsychiatric Disorders: Pathophysiological Mechanisms and Novel Treatments

Background

The human gut microbiome comprise a huge number of microorganisms with co-evolutionary associations with humans. It has been repeatedly revealed that bidirectional communication exists between the brain and the gut and involves neural, hormonal, and immunological pathways. Evidences from neuroscience researches over the past few years suggest that microbiota is essential for the development and maturation of brain systems that are associated to stress responses.

Method

This review provides that the summarization of the communication among microbiota, gut and brain and the results of preclinical and clinical studies on gut microbiota used in treatments for neuropsychiatric disorders.

Result

Recent studies have reported that diverse forms of neuropsychiatric disorders (such as autism, depression, anxiety, and schizophrenia) are associated with or modulated by variations in the microbiome, by microbial substrates, and by exogenous prebiotics, antibiotics, and probiotics.

Conclusion

The microbiota–gut–brain axis might provide novel targets for prevention and treatment of neuropsychiatric disorders. However, further studies are required to substantiate the clinical use of probiotics, prebiotics and FMT.

Gut-Brain Psychology: Rethinking Psychology From the Microbiota-Gut-Brain Axis

Mental disorders and neurological diseases are becoming a rapidly increasing medical burden. Although extensive studies have been conducted, the progress in developing effective therapies for these diseases has still been slow. The current dilemma reminds us that the human being is a superorganism. Only when we take the human self and its partner microbiota into consideration at the same time, can we better understand these diseases. Over the last few centuries, the partner microbiota has experienced tremendous change, much more than human genes, because of the modern transformations in diet, lifestyle, medical care, and so on, parallel to the modern epidemiological transition. Existing research indicates that gut microbiota plays an important role in this transition. According to gut-brain psychology, the gut microbiota is a crucial part of the gut-brain network, and it communicates with the brain via the microbiota-gut-brain axis. The gut microbiota almost develops synchronously with the gut-brain, brain, and mind. The gut microbiota influences various normal mental processes and mental phenomena, and is involved in the pathophysiology of numerous mental and neurological diseases. Targeting the microbiota in therapy for these diseases is a promising approach that is supported by three theories: the gut microbiota hypothesis, the "old friend" hypothesis, and the leaky gut theory. The effects of gut microbiota on the brain and behavior are fulfilled by the microbiota-gut-brain axis, which is mainly composed of the nervous pathway, endocrine pathway, and immune pathway. Undoubtedly, gut-brain psychology will bring great enhancement to psychology, neuroscience, and psychiatry. Various microbiota-improving methods including fecal microbiota transplantation, probiotics, prebiotics, a healthy diet, and healthy lifestyle have shown the capability to promote the function of the gut-brain, microbiota-gut-brain axis, and brain. It will be possible to harness the gut microbiota to improve brain and mental health and prevent and treat related diseases in the future.

Mind the gut: probiotics in paediatric neurogastroenterology

The gut-brain axis has recently emerged as a key modulator of human health and the intestinal microbiome has a well-recognised pivotal role in this strong connection. The aim of this narrative review is to update and summarise the effect and clinical applicability of probiotics in paediatric neurogastroenterology. The Cochrane Database and PubMed were searched using keywords relating to different subtypes of functional gastrointestinal disorders (FGIDs) and their symptoms, those relating to the CNS and related neurological or behavioural dysfunction as well as 'probiotic' OR 'probiotics'. Included papers were limited to those including children (aged 0-18 years) and using English language. Although significant effects of specific strains have been reported in infants with FGIDs, heterogeneity amongst the studies (different products and concentrations used and FGID subtypes), has limited the ability to draw an overall conclusion on the clinical value of probiotics. According to different meta-analyses of randomised controlled trials, the use of Lactobacillus reuteri (DSM 17938) was associated with a significant decrease in average crying time in infantile colic. There is moderate evidence for this strain and LGG and limited evidence (based on one study each) for the beneficial effect of VSL#3 and a three-strain bifidobacteria mix in abdominal pain FGIDs, particularly in the irritable bowel disease subgroup of children, but not in functional dyspepsia. There is currently no clear evidence of positive effects of oral probiotics in autistic spectrum disorder. Efficacy and safety of other strains or beneficial effects in other conditions still need to be proven, as probiotic properties are strain-specific, and data cannot be extrapolated to other brain-gut or mood diseases or to other probiotics of the same or different species. To transform the use of probiotics from a tempting suggestion to a promising treatment modality in neurogastroenterological disorders more accurate differentiation of the efficacy-proven strains, clarification of dose, duration, and outcome and a careful selection of the target patients are still necessary.

Neuropsychiatric Disorders: Influence of Gut Microbe to Brain Signalling

The microbiome gut brain (MGB) axis consists of bidirectional routes of communication between the gut and the brain. It has emerged as a potential therapeutic target for multiple medical specialties including psychiatry. Significant numbers of preclinical trials have taken place with some transitioning to clinical studies in more recent years. Some positive results have been reported secondary to probiotic administration in both healthy populations and specific patient groups. This review aims to summarise the current understanding of the MGB axis and the preclinical and clinical findings relevant to psychiatry. Significant differences have been identified between the microbiome of patients with a diagnosis of depressive disorder and healthy controls. Similar findings have occurred in patients diagnosed with bipolar affective disorder and irritable bowel syndrome. A probiotic containing Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium bifidum produced a clinically measurable symptom improvement in patients with depressive disorder. To date, some promising results have suggested that probiotics could play a role in the treatment of stress-related psychiatric disease. However, more well-controlled clinical trials are required to determine which clinical conditions are likely to benefit most significantly from this novel approach.

Gut microbiota, cognitive frailty and dementia in older individuals: a systematic review

Cognitive frailty, defined as the coexistence of mild cognitive impairment symptoms and physical frailty phenotype in older persons, is increasingly considered the main geriatric condition predisposing to dementia. Recent studies have demonstrated that gut microbiota may be involved in frailty physiopathology by promoting chronic inflammation and anabolic resistance. The contribution of gut microbiota to the development of cognitive impairment and dementia is less defined, even though the concept of "gut-brain axis" has been well demonstrated for other neuropsychiatric disorders. The aim of this systematic review was to summarize the current state-of-the-art literature on the gut microbiota alterations associated with cognitive frailty, mild cognitive impairment and dementia and elucidate the effects of pre- or probiotic administration on cognitive symptom modulation in animal models of aging and human beings. We identified 47 papers with original data (31 from animal studies and 16 from human studies) suitable for inclusion according to our aims. We concluded that several observational and intervention studies performed in animal models of dementia (mainly Alzheimer's disease) support the concept of a gut-brain regulation of cognitive symptoms. Modulation of vagal activity and bacterial synthesis of substances active on host neural metabolism, inflammation and amyloid deposition are the main mechanisms involved in this physiopathologic link. Conversely, there is a substantial lack of human data, both from observational and intervention studies, preventing to formulate any clinical recommendation on this topic. Gut microbiota modulation of cognitive function represents, however, a promising area of research for identifying novel preventive and treatment strategies against dementia.

Akebia quinata Decaisne aqueous extract acts as a novel anti-fatigue agent in mice exposed to chronic restraint stress

ETHNOPHARMACOLOGICAL RELEVANCE

Akebia quinata Decaisne extract (AQE; Lardizabalaceae) is used in traditional herbal medicine for stress- and fatigue-related depression, improvement of fatigue, and mental relaxation.

AIM OF THE STUDY

To clarify the effects of AQE on stress-induced fatigue, we investigated the neuroprotective pharmacological effects of A. quinata Decaisne in mice exposed to chronic restraint stress.

MATERIALS AND METHODS

Seven-week old C57BL/6 mice chronically stressed by immobilization for 3 h daily for 15 d and non-stressed control mice underwent daily oral administration of AQE or distilled water. The open field, sucrose preference, and forced swimming behavioral tests were carried out once weekly, and immunohistochemical analyses of NeuN, brain-derived neurotrophic factor (BDNF), phosphorylated cAMP response element-binding (CREB) protein, and BDNF receptor tropomyosin receptor kinase B (TrkB) in striatum and hippocampus were performed at the end of the experimental period. Brain levels of serotonin, adrenaline, and noradrenaline as well as serum levels of corticosterone were measured.

RESULTS

Behavioral tests showed that treatment with AQE improved all lethargic behaviors examined. AQE significantly attenuated the elevated levels of adrenaline, noradrenaline, and serotonin in the brain and corticosterone, alanine transaminase, and aspartate transaminase levels in the serum. Histopathological analysis showed that AQE reduced liver injury and lateral ventricle size in restraint-stress mice via inhibition of neuronal cell death. Immunohistochemical analysis showed increased phosphorylation of CREB and expression of BDNF and its receptor TrkB in striatum and hippocampus. Chlorogenic acid, isochlorogenic acid A, and isochlorogenic acid C were identified as the primary components of AQE. All three agents increased expression of BDNF in SH-SY5Y cells and PC12 cells with H₂O₂-induced neuronal cell damage.

CONCLUSIONS

AQE may have a neuroprotective effect and ameliorate the effects of stress and fatigue-associated brain damage through mechanisms involving regulation of BDNF-TrkB signaling.

Clostridium butyricum Attenuates Chronic Unpredictable Mild Stress-Induced Depressive-Like Behavior in Mice via the Gut-Brain Axis

Abnormal gut microbiome has been associated with depression. The mechanism of probiotics against depression remains unclear. This study aimed to determine whether Clostridium butyricum (Cb) could attenuate chronic unpredictable mild stress-induced depressive-like behavior and its possible mechanisms. Male C57BL/6 mice were subjected to chronic unpredictable mild stress (CUMS) and were treated with Cb. Depressive-like behavior was evaluated by a series of behavioral tests. The levels of cerebral 5-hydroxytryptamine (5-HT), brain derived neurotrophic factor (BDNF), glucagon-like peptide-1 (GLP-1) receptor and intestinal were measured. Cb treatment significantly improved CUMS-induced depressive-like behavior in mice. Meanwhile, Cb treatment exhibited prominent effects, increasing 5-HT and GLP-1 and upregulating BDNF expression. Furthermore, Cb-treated mice showed increased secretion of GLP-1 and upregulated GLP-1R expression. Taken together, our results demonstrate an antidepressive effect of Cb in CUMS mice partially attributed to stimulation of intestinal GLP-1 secretion and activation of cerebral GLP-1R.

Probiotic treatment reduces the autistic-like excitation/inhibition imbalance in juvenile hamsters induced by orally administered propionic acid and clindamycin

Increasing evidence suggests that the gut microbiota plays a key role in the central nervous system (CNS), and alterations of the gut microbiota composition due to environmental factors can contribute to neurodevelopmental disorders. Animal modeling may help to identify drugs that can normalize the altered gut microbiota and thereby ameliorate abnormal brain signaling pathways. The purpose of the present study was to investigate the therapeutic potency of probiotics such as Bifidobacteria and Lactobacilli on glutamate excitotoxicity as a neurotoxic effect induced by clindamycin and propionic acid (PPA) in juvenile hamsters. Fifty young golden Syrian hamsters weighing between 60 and 70 g were enrolled in the study. The hamsters were randomly divided into five groups, each with ten hamsters. The hamsters in the control group only received phosphate-buffered saline orally. The PPA-treated group received a neurotoxic dose of 250 mg PPA/kg body weight (BW)/day for three days. The clindamycin-treated group received 30 mg clindamycin/kg BW as a single orogastric dose on the day the experiment started. The two therapeutic groups received the same doses of PPA and clindamycin followed by 0.2 g probiotic/kg BW for three weeks. Biochemical parameters related to glutamate excitotoxicity were investigated in brain homogenates from each group of hamsters. Additionally, the development of pathogenic bacteria was monitored in stool samples from all groups. The microbiology results of the present study revealed descriptive changes in the fecal microbiota and the appearance of Clostridium species in the hamsters treated with clindamycin and PPA. Additionally, the effectiveness of the probiotic in the restoration of the normal gut microbiota was demonstrated. Moreover, clindamycin and PPA were found to induce a significant depletion of Mg²⁺ and γ-aminobutyric acid (GABA) and a remarkable increase in the Na⁺/Mg²⁺ and glutamate/GABA ratios but non-significant changes in the absolute levels of K⁺, Na⁺ and glutamate. The bacteria overgrowth induced by PPA and clindamycin in the present study effectively showed signs of neuronal toxicity. The study indicates that probiotics can be used safely to ameliorate glutamate excitotoxicity mostly through increasing depleted GABA and Mg²⁺ and decreasing the excitatory neurotransmitter, glutamate.

Impact of gut microbiota on neurological diseases: Diet composition and novel treatments

Gut microbiota has significant effects on the structure and function of the enteric and central nervous system including human behaviour and brain regulation. Herein, we analyze the role of this intestinal ecosystem, the effects of dietary changes and the administration of nutritional supplements, such as probiotics, prebiotics, or fecal transplantation in neuropsychiatric disorders. Numerous factors have been highlighted to influence gut microbiota composition, including genetics, health status, mode of birth delivery and environment. However, diet composition and nutritional status has been repeatedly shown to be one of the most critical modifiable factors of this ecosystem. A comprehensively analysis of the microbiome-intestine-brain axis has been performed, including the impact of intestinal bacteria in alterations in the nervous, immune and endocrine systems and their metabolites. Finally, we discuss the latest literature examining the effects of diet composition, nutritional status and microbiota alterations in several neuropsychiatric disorders, such as autism, anxiety, depression, Alzheimer's disease and anorexia nervosa.

Future Direction for Using Artificial Intelligence to Predict and Manage Hypertension

PURPOSE OF REVIEW

Evidence that artificial intelligence (AI) is useful for predicting risk factors for hypertension and its management is emerging. However, we are far from harnessing the innovative AI tools to predict these risk factors for hypertension and applying them to personalized management. This review summarizes recent advances in the computer science and medical field, illustrating the innovative AI approach for potential prediction of early stages of hypertension. Additionally, we review ongoing research and future implications of AI in hypertension management and clinical trials, with an eye towards personalized medicine.

RECENT FINDINGS

Although recent studies demonstrate that AI in hypertension research is feasible and possibly useful, AI-informed care has yet to transform blood pressure (BP) control. This is due, in part, to lack of data on AI's consistency, accuracy, and reliability in the BP sphere. However, many factors contribute to poorly controlled BP, including biological, environmental, and lifestyle issues. AI allows insight into extrapolating data analytics to inform prescribers and patients about specific factors that may impact their BP control. To date, AI has been mainly used to investigate risk factors for hypertension, but has not yet been utilized for hypertension management due to the limitations of study design and of physician's engagement in computer science literature. The future of AI with more robust architecture using multi-omics approaches and wearable technology will likely be an important tool allowing to incorporate biological, lifestyle, and environmental factors into decision-making of appropriate drug use for BP control.

Sex-Based Differences in Gut Microbiota Composition in Response to Tuna Oil and Algae Oil Supplementation in a D-galactose-Induced Aging Mouse Model

Our previous work indicated that a mixture of tuna oil and algae oil treatment in male mice effectively relieved D-galactose (D-gal)-induced aging and resulted in gut microbiota alterations, and that the best anti-aging effects were observed for a tuna oil to algae oil ratio of 1:2. However, the possibility of a sex-based difference in the anti-aging effect of the tuna oil and algae oil mixture or gut microbiota variation, has rarely been investigated. In this study, the anti-aging effect of an oil mixture (1:2) in male and female mice was measured, and oil treatment improved the learning and cognition of mice that were damaged by D-gal, increased the activities of anti-oxidative enzymes, and decreased the level of MDA, which acted as a hallmark of oxidative damage to lipids. Male mice showed better anti-aging effects than female mice with a specific oil mixture ratio, and the clinical drug donepezil showed a similar or better effect on aging alleviation than oil treatments in both sexes. On the other hand, the same oil treatment led to different gut microbiota composition alterations in male and female mice. Redundancy analysis (RDA) identified 31 and 30 key operational taxonomic units (OTUs) in the male and female mice, respectively, and only three of these OTUs overlapped. Moreover, the abundance of Lactobacillus and several probiotic-like butyric acid producers was higher in male mice than in female mice, whereas the abundance of some inflammation-related genera, such as Clostridium XlVa, was lower in male mice. In conclusion, this study indicated the sex-based differences related to the anti-aging effects of tuna oil and algae oil treatment are accompanied by sex-based differences in gut microbiota modulation.

The anxiolytic effect of probiotics: A systematic review and meta-analysis of the clinical and preclinical literature

Background

Probiotics have generated intensive research interest in recent years as a novel mode of treatment for physical and mental illness. Nevertheless, the anxiolytic potential of probiotics remains unclear. The present systematic review and meta-analysis aimed to evaluate the clinical and preclinical (animal model) evidence regarding the effect of probiotic administration on anxiety.

Methods

The PubMed, PsycINFO, and Web of Science databases were reviewed for preclinical and clinical studies that met the defined inclusion and exclusion criteria. The effects of probiotics on anxiety-like behavior and symptoms of anxiety were analyzed by meta-analyses. Separate subgroup analyses were conducted on diseased versus healthy animals, specific preclinical probiotic species, and clinical versus healthy human samples.

Results

Data were extracted from 22 preclinical studies (743 animals) and 14 clinical studies (1527 individuals). Overall, probiotics reduced anxiety-like behavior in animals (Hedges’ g = -0.47, 95% CI -0.77 –-0.16, p = 0.004). Subgroup analyses revealed a significant reduction only among diseased animals. Probiotic species-level analyses identified only Lactobacillus (L.) rhamnosus as an anxiolytic species, but these analyses were broadly under-powered. Probiotics did not significantly reduce symptoms of anxiety in humans (Hedges’ g = -0.12, 95% CI -0.29–0.05, p = 0.151), and did not differentially affect clinical and healthy human samples.

Conclusions

While preclinical (animal) studies suggest that probiotics may help reduce anxiety, such findings have not yet translated to clinical research in humans, perhaps due to the dearth of extant research with clinically anxious populations. Further investigation of probiotic treatment for clinically relevant anxiety is warranted, particularly with respect to the probiotic species L. rhamnosus.

Long-Term Diet Supplementation with Lactobacillus paracasei K71 Prevents Age-Related Cognitive Decline in Senescence-Accelerated Mouse Prone 8

This study aimed to assess the suppressive effect of long-term diet supplementation with Lactobacillus strains on cognitive decline in the senescence-accelerated mouse prone 8 (SAMP8) model. For 43 weeks, fourteen-week-old female SAMP8 mice were fed a standard diet containing 0.05% (w/w) Lactobacillus casei subsp. casei 327 (L. 327) or Lactobacillusparacasei K71 (L. K71) derived from rice grains and sake lees, respectively. SAMP8 mice that were fed a L. K71-supplemented diet had better cognitive performance compared with the control and L. 327 groups in the Barnes maze and passive avoidance tests. An ELISA analysis revealed that the levels of serotonin were elevated in the serum and brain tissue of L. K71-fed mice. The protein expression levels of brain-derived neurotrophic factor (BDNF), cAMP response element binding protein (CREB), and phosphorylated CREB were evaluated using western blot. Long-term administration of L. K71 resulted in increased protein expression of BDNF and CREB phosphorylation in the hippocampus. These results suggest that prolonged intake of a diet supplemented with a Lactobacillus strain derived from sake lees may prevent age-dependent cognitive decline by upregulating BDNF expression in the hippocampus.

Long-Term Diet Supplementation with Lactobacillus paracasei K71 Prevents Age-Related Cognitive Decline in Senescence-Accelerated Mouse Prone 8

This study aimed to assess the suppressive effect of long-term diet supplementation with Lactobacillus strains on cognitive decline in the senescence-accelerated mouse prone 8 (SAMP8) model. For 43 weeks, fourteen-week-old female SAMP8 mice were fed a standard diet containing 0.05% (w/w) Lactobacillus casei subsp. casei 327 (L. 327) or Lactobacillusparacasei K71 (L. K71) derived from rice grains and sake lees, respectively. SAMP8 mice that were fed a L. K71-supplemented diet had better cognitive performance compared with the control and L. 327 groups in the Barnes maze and passive avoidance tests. An ELISA analysis revealed that the levels of serotonin were elevated in the serum and brain tissue of L. K71-fed mice. The protein expression levels of brain-derived neurotrophic factor (BDNF), cAMP response element binding protein (CREB), and phosphorylated CREB were evaluated using western blot. Long-term administration of L. K71 resulted in increased protein expression of BDNF and CREB phosphorylation in the hippocampus. These results suggest that prolonged intake of a diet supplemented with a Lactobacillus strain derived from sake lees may prevent age-dependent cognitive decline by upregulating BDNF expression in the hippocampus.

The Ramazzini Institute 13-week pilot study on glyphosate and Roundup administered at human-equivalent dose to Sprague Dawley rats: effects on the microbiome

BACKGROUND

Glyphosate-based herbicides (GBHs) are broad-spectrum herbicides that act on the shikimate pathway in bacteria, fungi, and plants. The possible effects of GBHs on human health are the subject of an intense public debate for both its potential carcinogenic and non-carcinogenic effects, including its effects on microbiome. The present pilot study examines whether exposure to GBHs at doses of glyphosate considered to be "safe" (the US Acceptable Daily Intake - ADI - of 1.75 mg/kg bw/day), starting from in utero, may modify the composition of gut microbiome in Sprague Dawley (SD) rats.

METHODS

Glyphosate alone and Roundup, a commercial brand of GBHs, were administered in drinking water at doses comparable to the US glyphosate ADI (1.75 mg/kg bw/day) to F0 dams starting from the gestational day (GD) 6 up to postnatal day (PND) 125. Animal feces were collected at multiple time points from both F0 dams and F1 pups. The gut microbiota of 433 fecal samples were profiled at V3-V4 region of 16S ribosomal RNA gene and further taxonomically assigned and assessed for diversity analysis. We tested the effect of exposure on overall microbiome diversity using PERMANOVA and on individual taxa by LEfSe analysis.

RESULTS

Microbiome profiling revealed that low-dose exposure to Roundup and glyphosate resulted in significant and distinctive changes in overall bacterial composition in F1 pups only. Specifically, at PND31, corresponding to pre-pubertal age in humans, relative abundance for Bacteriodetes (Prevotella) was increased while the Firmicutes (Lactobacillus) was reduced in both Roundup and glyphosate exposed F1 pups compared to controls.

CONCLUSIONS

This study provides initial evidence that exposures to commonly used GBHs, at doses considered safe, are capable of modifying the gut microbiota in early development, particularly before the onset of puberty. These findings warrant future studies on potential health effects of GBHs in early development such as childhood.

Recognizing Depression from the Microbiota⁻Gut⁻Brain Axis

Major depression is one of the leading causes of disability, morbidity, and mortality worldwide. The brain⁻gut axis functions are disturbed, revealed by a dysfunction of the brain, immune system, endocrine system, and gut. Traditional depression treatments all target the brain, with different drugs and/or psychotherapy. Unfortunately, most of the patients have never received any treatment. Studies indicate that gut microbiota could be a direct cause for the disorder. Abnormal microbiota and the microbiota⁻gut⁻brain dysfunction may cause mental disorders, while correcting these disturbance could alleviate depression. Nowadays, the gut microbiota modulation has become a hot topic in treatment research of mental disorders. Depression is closely related with the health condition of the brain⁻gut axis, and maintaining/restoring the normal condition of gut microbiota helps in the prevention/therapy of mental disorders.

Current and future uses of probiotics

The relationship between host and gut microbiota has been the topic of research in recent decades, with particular emphasis on various species of bacteria and their distinct role in health promotion. Early promising research led to the new term probiotic, coined to describe these beneficial bacteria. This early research has laid the foundation for various proposed mechanisms of probiotic effects on health. This article describes current areas of established probiotic use and introduces areas of current investigation, including psychobiotics, which may help patients suffering from psychiatric illness.

Beneficial psychological effects of novel psychobiotics in diabetic rats: the interaction among the gut, blood and amygdala

Type 2 diabetes mellitus (T2DM) can lead to major complications such as psychiatric disorders which include depressive and anxiety-like behaviors. The association of the gut-brain axis in the development of such disorders, especially in T2DM, has been elucidated; however, gut dysbiosis is also reported in patients with T2DM. Hence, the regulation of the gut-brain axis, in particular, the gut-amygdala, as a vital region for the regulation of behavior is essential. Thirty-five male Wistar rats were divided into six groups. To induce T2DM, treatment groups received high-fat diet and 35 mg/kg streptozotocin. Then, supplements of Lactobacillus plantarum, inulin or their combination were administered to each group for 8 weeks. Finally, the rats were sacrificed for measurement of blood and tissue parameters after behavioral testing. The findings demonstrated the favorable effects of the psychobiotics (L. plantarum, inulin or their combination) on oxidative markers of the blood and amygdala (superoxide dismutase, glutathione peroxidase, malondialdehyde and total antioxidant capacity), as well as on concentrations of amygdala serotonin and brain-derived neurotrophic factor, in the diabetic rats. In addition, beneficial effects were observed on the elevated plus maze and forced swimming tests with no change in locomotor activity of the rats. There was a strong correlation between the blood and amygdala oxidative markers, insulin and fasting blood sugar with depressive and anxiety-like behaviors. Our results identified L. plantarum ATCC 8014 and inulin or their combination as novel psychobiotics that could improve the systemic and nervous antioxidant status and improve amygdala performance and beneficial psychotropic effects.

The Gut Microbiota and Alzheimer's Disease

The gut microbiota comprises a complex community of microorganism species that resides in our gastrointestinal ecosystem and whose alterations influence not only various gut disorders but also central nervous system disorders such as Alzheimer's disease (AD). AD, the most common form of dementia, is a neurodegenerative disorder associated with impaired cognition and cerebral accumulation of amyloid-β peptides (Aβ). Most notably, the microbiota-gut-brain axis is a bidirectional communication system that is not fully understood, but includes neural, immune, endocrine, and metabolic pathways. Studies in germ-free animals and in animals exposed to pathogenic microbial infections, antibiotics, probiotics, or fecal microbiota transplantation suggest a role for the gut microbiota in host cognition or AD-related pathogenesis. The increased permeability of the gut and blood-brain barrier induced by microbiota dysbiosis may mediate or affect AD pathogenesis and other neurodegenerative disorders, especially those associated with aging. In addition, bacteria populating the gut microbiota can secrete large amounts of amyloids and lipopolysaccharides, which might contribute to the modulation of signaling pathways and the production of proinflammatory cytokines associated with the pathogenesis of AD. Moreover, imbalances in the gut microbiota can induce inflammation that is associated with the pathogenesis of obesity, type 2 diabetes mellitus, and AD. The purpose of this review is to summarize and discuss the current findings that may elucidate the role of the gut microbiota in the development of AD. Understanding the underlying mechanisms may provide new insights into novel therapeutic strategies for AD.

Extracellular signal-regulated kinase activation in the spinal cord contributes to visceral hypersensitivity induced by craniofacial injury followed by stress

BACKGROUND

We previously developed an animal model to examine mechanisms that underlie the emergence of visceral hypersensitivity modeling pain characteristics of temporomandibular disorder (TMD) patients with comorbid irritable bowel syndrome (IBS). In ovariectomized (OVx) rats with estradiol (E2) replacement, visceral hypersensitivity developed subsequent to masseter muscle inflammation followed by repeated forced swim (FS) stress. The purpose of this study was to investigate whether activation of extracellular signal-regulated kinase (ERK) in the spinal cord contributes to visceral hypersensitivity in this overlapping pain model.

METHODS

In OVx with E2 replacement rats masseter muscle inflammation was followed by 3 day FS (comorbid condition). Depression-like behaviors were assessed by sucrose preference and in the elevated plus maze, and visceral sensitivity was measured by the visceromotor response (VMR) to colorectal distention. The protein level of ERK1/2 and phosphorylated ERK1/2 (p-ERK1/2) in the L6-S2 dorsal spinal cord was analyzed by western blot.

KEY RESULTS

FS stress decreased sucrose consumption in E2 replaced rats in sucrose preference test. The expression of p-ERK1/2 in the L6-S2 dorsal spinal cord increased significantly in E2 with comorbid rats. Intrathecal injection of mitogen-activated protein kinase (MAPK) kinase (MEK) inhibitor PD98059 blocked the visceral hypersensitivity induced by masseter muscle inflammation combined with FS stress.

CONCLUSIONS & INFERENCES

These data indicate that ERK1/2 activation contributes to the visceral hypersensitivity evoked by craniofacial inflammation pain combined with stress. The results may provide a new therapeutic avenue for alleviating overlapping pain conditions.

Influence of Altered Gut Microbiota Composition on Aging and Aging-Related Diseases

The gut microbiota forms a large community that coexists with all species, including humans and rodents. Genome projects have been conducted by many researchers in nearly every country to better understand and treat diseases that lead to death in humans. However, the gut microbiota is known as a "second genome" because it includes microbes, genomic DNA, proteins, and metabolites. A large number of studies have revealed the importance of the gut microbiota. In elderly people, the diversity of the gut microbiota is reduced and there is an increased incidence of degenerative diseases, including Alzheimer's and Parkinson's, and decreased cognitive and memory functions. However, the administration of pre/probiotics can help to improve the symptoms of these diseases. Therefore, we believe that the gut microbiota is important for maintaining homeostasis and diversity, as well as for avoiding gastrointestinal tract-derived diseases and improving health in the elderly population.

Flammulina velutipes polysaccharides improve scopolamine-induced learning and memory impairment in mice by modulating gut microbiota composition

Flammulina velutipes polysaccharides (FVP) and the FVP-induced microbiota have been proved to be effective in improving learning and memory impairment in mice.

Effects of the Oral Ingestion of Probiotics on Brain Damage in a Transient Model of Focal Cerebral Ischemia in Mice

BACKGROUND

Probiotics are microorganisms that may influence brain function via altering brain neurochemistry. New research evidence suggests that probiotic bacteria might protect tissue damage through diminishing the production of free radicals and/or inflammatory cytokines. Therefore, this study was designed to evaluate the effects of probiotic bacteria on the prevention or reduction of brain damage in an experimental model of stroke in mice.

METHODS

In this study, 30 male BLC57 mice were randomly divided into 6 equal groups. Focal cerebral ischemia was induced via middle cerebral artery occlusion for 45 minutes, followed by 24 hours of reperfusion, in the mice. Probiotics at a concentration of 10⁷ CFU/mL were administered by oral gavage daily for 14 days before ischemia. Infarct size, neurological outcome, and biochemical markers were measured 24 hours after brain ischemia. Statistical analysis were performed using the one-way ANOVA and/or Kruskal-Wallis ANOVA on rank by Sigma Stat (2.0; Jandel Scientific) software.

RESULTS

Our results indicated that pretreatment with probiotics significantly reduced infarct size by 52% (P=0.001) but could not improve neurological function (P=0.26). Moreover, the administration of probiotics significantly decreased the malondialdehyde content (P=0.001) and the tumor necrosis factor-alpha level (P=0.004) in the ischemic brain tissue.

CONCLUSION

The findings of the present study showed that probiotic supplements might be useful in the prevention or attenuation of brain ischemic injury in patients at risk of stroke. Probiotics may open new therapeutic alternatives for the prevention of stroke. More preclinical and clinical studies are, however, needed to clarify their efficacy in cerebral stroke.

The stress concept in gastroenterology: from Selye to today

More than eighty years after Hans Selye (1907-1982) first developed a concept describing how different types of environmental stressors affect physiological functions and promote disease development (called the "general adaptation syndrome") in 1936, we herein review advances in theoretical, mechanistic, and clinical knowledge in stress research, especially in the area of gastroenterology, and summarize progress and future perspectives arising from an interdisciplinary psychoneurobiological framework in which genetics, epigenetics, and other advanced ( omics) technologies in the last decade continue to refine knowledge about how stress affects the brain-gut axis in health and gastrointestinal disease. We demonstrate that neurobiological stress research continues to be a driving force for scientific progress in gastroenterology and related clinical areas, inspiring translational research from animal models to clinical applications, while highlighting some areas that remain incompletely understood, such as the roles of sex/gender and gut microbiota in health and disease. Future directions of research should include not only the genetics of the stress response and resilience but also epigenetic contributions.

Metagenome Analysis of Bodily Microbiota in a Mouse Model of Alzheimer Disease Using Bacteria-derived Membrane Vesicles in Blood

Emerging evidence has suggested that the gut microbiota contribute to brain dysfunction, including pathological symptoms of Alzheimer disease (AD). Microbiota secrete membrane vesicles, also called extracellular vesicles (EVs), which contain bacterial genomic DNA fragments and other molecules and are distributed throughout the host body, including blood. In the present study, we investigated whether bacteria-derived EVs in blood are useful for metagenome analysis in an AD mouse model. Sequence readings of variable regions of 16S rRNA genes prepared from blood EVs in Tg-APP/PS1 mice allowed us to identify over 3,200 operational taxonomic units corresponding to gut microbiota reported in previous studies. Further analysis revealed a distinctive microbiota landscape in Tg-APP/PS1 mice, with a dramatic alteration in specific microbiota at all taxonomy levels examined. Specifically, at the phylum level, the occupancy of p_Firmicutes increased, while the occupancy of p_Proteobacteria and p_Bacteroidetes moderately decreased in Tg-APP/PS1 mice. At the genus level, the occupancy of g_Aerococcus, g_Jeotgalicoccus, g_Blautia, g_Pseudomonas and unclassified members of f_Clostridiale and f_Ruminococcaceae increased, while the occupancy of g_Lactobacillus, unclassified members of f_S24-7, and g_Corynebacterium decreased in Tg-APP/PS1 mice. A number of genus members were detected in Tg-APP/PS1 mice, but not in wild-type mice, while other genus members were detected in wild-type mice, but lost in Tg-APP/PS1 mice. The results of the present study suggest that the bodily microbiota profile is altered in Tg-APP/PS1 mice, and that blood EVs are useful for the metagenome analysis of bodily microbiota in AD.

Psychobiotics: A new approach for treating mental illness?

Gut microbiomes may have a significant impact on mood and cognition, which is leading experts towards a new frontier in neuroscience. Studies have shown that increase in the amount of good bacteria in the gut can curb inflammation and cortisol level, reduces symptoms of depression and anxiety, lowers stress reactivity, improves memory and even lessens neuroticism and social anxiety. This shows that, probably the beneficial gut bacteria or probiotics function mechanistically as delivery vehicles for neuroactive compounds. Thus, a psychobiotic is a live organism, when ingested in adequate amounts, produces a health benefit in patients suffering from psychiatric illness. Study of these novel class of probiotics may open up the possibility of rearrangement of intestinal microbiota for effective management of various psychiatric disorders.

Scutellarin Prevents Nonalcoholic Fatty Liver Disease (NAFLD) and Hyperlipidemia via PI3K/AKT-Dependent Activation of Nuclear Factor (Erythroid-Derived 2)-Like 2 (Nrf2) in Rats

Background

Nonalcoholic fatty liver disease (NAFLD) is a condition characterized by excessive fat accumulation in the form of triglycerides. The incidence of NAFLD and hyperlipidemia, with their associated risks of end-stage liver and cardiovascular diseases, is increasing rapidly. This study aimed to investigate the effects of scutellarin on the experimental NAFLD in high-fat diet fed and chronic stress rats, and its possible mechanism.

Material/Methods

Sprague-Dawley rats were fed with high-fat diet and subjected to chronic stress for 12 weeks, and administered orally with scutellarin for 4 weeks (n=8), and then blood and livers were harvested for analyzing. Enzyme activity assay, immunofluorescence, Western blot, and quantitative RT-PCR were performed to analyze the factors of the oxidant/antioxidant system and pathway.

Results

After the high-fat diet and chronic stress administration for 12 weeks, serum and liver lipid metabolism of treatment groups with the different doses of SCU effectively improved and the degree of oxidative damage reduced. Using Western blot assay and immunofluorescence (IF) staining assay, Nrf2, HO-1, and PI3K, and AKT proteins significantly increased after SCU treatment for 4 weeks (P<0.01). The hepatic mRNA expression of HO-1, NQO1, and Nrf2 in SCU treatment groups was upregulated significantly through quantitative RT-PCR assay (P<0.05). However, compared to the positive control group, no difference was detected in the SCU (100 or 300 mg/kg) groups (P>0.05). These results indicate that SCU protects against NAFLD in rats via attenuation of oxidative stress.

Conclusions

The antioxidant effects of SCU on NAFLD are possibly dependent on PI3K/AKT activation with subsequent Nrf2 nuclear translocation, which increases expression of HO-1 and NQO1. We therefore suggest that breviscapine may be a potentially useful therapeutic strategy for NAFLD and hyperlipidemia.

Implications of the gut microbiota in vulnerability to the social avoidance effects of chronic social defeat in male mice

Appreciable evidence suggests that perturbations within the gut microbiome and the immune system may play a key role in the pathogenesis of depression stemming from earlier stressful experiences. In the present investigation we examined whether microbial changes in cecum contents were associated with social avoidance behaviors, a feature of depression, and pro-inflammatory variations among socially stressed mice. Male C57BL/6 mice experienced social defeat or a control condition once a day for 10 consecutive days. Social avoidance behaviors were examined three weeks after the last defeat or control episode and blood, brain, and cecum contents were collected 24h afterward for the determination of corticosterone, pro-inflammatory cytokines, and microbial populations. Mice that were most susceptible to the behavioral effects of chronic social defeat (reflected by severe social avoidance behaviors) displayed the greatest changes within particular sets of bacteria at the phylum and genus taxonomic ranks. Although plasma and brain cytokines were not significantly altered in socially defeated mice, changes in the mRNA expression of interleukin (IL)-1β and IL-6 within the prefrontal cortex were associated with elevated abundance of Flavobacterium spp. and reduced abundance of Turicibacter spp., which were also strongly correlated to social avoidance severity. Although at this time a causal connection cannot be inferred, these results point to the possibility that specific clusters of bacterial communities in cecum contents may be linked to vulnerability to social deficits stemming from prolonged social stressor experiences.

Microbiota abnormalities and the therapeutic potential of probiotics in the treatment of mood disorders

Major depressive disorder (MDD) and bipolar disorder (BD) are among the leading causes of burden and disability worldwide. Despite intensified research efforts to improve the treatment options and remission rates in mood disorders, no disease modifying treatment exists for these disorders. Accumulating evidence implicates the involvement of the gut microbiota in processes relevant to etiopathology of central nervous system-based disorders. The objective of this article was to critically evaluate the evidence supporting the link between gastrointestinal microbiota and mood disorders and to discuss the potential benefits of using probiotics in the treatment of MDD and BD. The concept of psychobiotics, which is bacterial-based interventions with mental health benefit, is emerging in the field. On the other hand, while probiotics might potentially represent a significant advance, specific roles of microbiota in the pathophysiology of mood disorders still need further investigation along with intervention studies.

Probiotic treatment protects against the pro-depressant-like effect of high-fat diet in Flinders Sensitive Line rats

Major depressive disorder (MDD) is highly associated with dysmetabolic conditions, such as obesity and diabetes mellitus type 2, and the gut microbiota may interact with both disease entities. We have previously shown that a high-fat diet (HFD) exacerbated depressive-like behaviour uniquely in Flinders Sensitive Line (FSL) rats that inherently present with an increased level of depressive-like behaviour compared with Flinders Resistant Line (FRL) rats. We therefore investigated whether multispecies probiotics possessed anti-depressant-like effect in FSL rats or protected against the pro-depressant-like effect of HFD. We also examined blood and cerebral T cell subsets as well as plasma cytokines. Lastly, we investigated the effect of HFD in outbred Sprague-Dawley (SD) rats to substantiate the association between depressive-like behaviour and any immunological measures affected by HFD. HFD exacerbated the depressive-like behaviour in FSL rats in the forced swim test, whereas SD rats remained unaffected. Probiotic treatment completely precluded the pro-depressant-like effect of HFD, but it did not affect FSL rats on control diet. Cerebral T lymphocyte CD4/8 ratios closely mirrored the behavioural changes, whereas the proportions of Treg and Th17 subsets were unaltered. No association between blood and brain CD4/8 ratios were evident; nor did plasma cytokine levels change as a consequence of HFD of probiotic treatment. Our findings suggest that MDD may hold a dysmetabolic component that responds to probiotic treatment. This finding has wide implications owing to the high metabolic comorbidity in MDD. Furthermore, the close association between depressive-like behaviour and cerebral T cell populations demonstrate lymphocyte-brain interactions as a promising future research area in the field of psychoneuroimmunology.

Anti-oxidative effects of safranal on immobilization-induced oxidative damage in rat brain

Safranal, a major constituent of saffron, possesses antioxidant and anti-apoptotic properties showing considerable neuroprotective effects. The present study was designed to investigate the effects of safranal against restraint stress induced oxidative damage in the rat brain. For inducing the chronic restraint stress, rats were kept in the restrainers for 1h every day, for 21 consecutive days, then, the animals received systemic administrations of vehicle (0.1% DMSO) acted as the control group or safranal daily for 21days. Results indicated that the rats submitted to restraint stress showed an increase in the immobility time versus the non-stress rats. In addition, stress decreased number of crossing in the rats submitted to restraint stress versus the non-stress animals. Treatment with safranal (0.75mg/kg) showed a significant reduction in the immobility time compared to the non-treated stress group, while, the treatment improved the number of crossing in rats submitted to restraint stress versus the vehicle-treated stress rats. In the stressed animals that received vehicle, the MDA level was significantly higher and the levels of GSH and antioxidant enzymes were significantly lower than the non-stressed rats. Safranal ameliorated the changes in the stressed animals as compared with the control groups. The present findings indicate that safranal might be effective against depressant-like effects induced by chronic stress via modulating brain oxidative response.

Vasopressin deletion is associated with sex-specific shifts in the gut microbiome

Brattleboro rats harbor a spontaneous deletion of the arginine-vasopressin (Avp) gene. In addition to diabetes insipidus, these rats exhibit low levels of anxiety and depressive behaviors. Recent work on the gut-brain axis has revealed that gut microbiota can influence anxiety behaviors. Therefore, we studied the effects of Avp gene deletion on gut microbiota. Since Avp gene expression is sexually different, we also examined how Avp deletion affects sex differences in gut microbiota. Males and females show modest but differentiated shifts in taxa abundance across 3 separate Avp deletion genotypes: wildtype (WT), heterozygous (Het) and AVP-deficient Brattleboro (KO) rats. For each sex, we found examples of taxa that have been shown to modulate anxiety behavior, in a manner that correlates with anxiety behavior observed in homozygous knockout Brattleboro rats. One prominent example is Lactobacillus, which has been reported to be anxiolytic: Lactobacillus was found to increase in abundance in inverse proportion to increasing gene dosage (most abundant in KO rats). This genotype effect of Lactobacillus abundance was not found when females were analyzed independently. Therefore, Avp deletion appears to affect microbiota composition in a sexually differentiated manner.

Effect of Fluoxetine on the Hippocampus of Wistar Albino Rats in Cold Restraint Stress Model

INTRODUCTION

Stress has been known to be a potential modulator of learning and memory. Long term stress can lead to depression. Fluoxetine is a selective serotonin reuptake inhibitor group of drug used in the treatment of depression.

AIM

The present study was conducted to evaluate the potential of Fluoxetine on cold restraint induced stress in the hippocampus of Wistar rats.

MATERIALS AND METHODS

A total of 18 male wistar albino rats were divided randomly into three groups (n=6). Group 1 was the control group which were kept in normal laboratory conditions. Group 2 was the negative control group which were given cold restraint stress for period of four weeks. Group 3 was the experimental group, where the animals were pretreated with fluoxetine 10 mg/kg for a period of one week followed by cold restraint stress for 30 minutes and cotreated with fluoxetine 10 mg/kg for a period of four weeks. The whole study was done for a period of five weeks followed by behavioural studies and subsequently sacrificed with removal of brain for various histological, Immunohistochemical (IHC), neurochemical and antioxidant analysis. The values were expressed as Mean±SEM. One-way analysis of variance followed by Tukey's multiple comparisons test was used for the comparison of means. A probability of 0.05 and less was taken as statistically significant using Prism Graphpad software version 6.01.

RESULTS

The results show there was significant improvement in the Morris water maze test after treatment with fluoxetine in Group 2. Similar results were also noted in the levels of neurotransmitters and antioxidant levels in brain and also in the number of cells counted in IHC and histological studies by H&E when Group 3 was compared with Group 2. The treatment reversed the damage in Group 2 which was comparable with the control group.

CONCLUSION

The results revealed that administration of fluoxetine 10 mg/kg given orally has a potential antistressor effect by improving the neurogenic and neuroprotective effect on the cold restraint stress induced hippocampal damage.