Clinical trial of a probiotic and herbal supplement for lung health.

Introduction: Dysbiosis of the gut microbiome may augment lung disease via the gut-lung axis. Proteobacteria may contribute to tissue proteolysis followed by neutrophil recruitment, lung tissue injury, and perpetuation of chronic inflammation. To study the effects of probiotics across the gut-lung axis, we sought to determine if a Lactobacillus probiotic and herbal blend was safe and well-tolerated in healthy volunteers and asthmatic patients. Methods: We conducted a 1-month randomized, open-label clinical trial in Cork, Ireland with healthy and asthmatic patients who took the blend twice a day. The primary endpoint was safety with exploratory endpoints including quality of life, lung function, gut microbiome ecology, and inflammatory biomarkers. Results: All subjects tolerated the blend without adverse events. Asthmatic subjects who took the blend showed significant improvements in lung function as measured by forced expiratory volume and serum short chain fatty acid levels from baseline to Week 4. The gut microbiome of asthmatic subjects differed significantly from controls, with the most prominent difference in the relative abundance of the proteobacteria Escherichia coli. Administration of the probiotic maintained overall microbial community architecture with the only significant difference being an increase in absolute abundance of the probiotic strains measured by strain-specific PCR. Conclusion: This study supports the safety and efficacy potential of a Lactobacillus probiotic plus herbal blend to act on the gut-lung axis. However, due to the lack of a control group, a longer blinded, placebo-controlled study will be warranted to confirm the efficacy improvements observed in this trial. Clinical trial registration: https://clinicaltrials.gov/, identifier NCT05173168.

Supplementation with milk fat globule membrane from early life reduces maternal separation-induced visceral pain independent of enteric nervous system or intestinal permeability changes in the rat.

Nutritional approaches have emerged over the past number of years as suitable interventions to ameliorate the enduring effects of early life stress. Maternal separation (MS) is a rodent model of early life stress which induces widespread changes across the microbiota-gut-brain axis. Milk fat globule membrane (MFGM) is a neuroactive membrane structure that surrounds milk fat globules in breast milk and has been shown to have positive health effects in infants, yet mechanisms behind this are not fully known. Here, we investigated the effects of MFGM supplementation from birth on a variety of gut-brain signalling pathways in MS and non-separated control animals across the lifespan. Specifically, visceral sensitivity as well as spatial and recognition memory were assessed in adulthood, while gut barrier permeability, enteric nervous system (ENS) and glial network structure were evaluated in both early life and adulthood. MS resulted in visceral hypersensitivity, which was ameliorated to a greater extent by supplementation with MFGM from birth. Modest effects of both MS and dietary supplementation were noted on spatial memory. No effects of MS were observed on enteric neuronal or glial networks in early life or adulthood, however an increase in the immunoreactivity of ßIII-tubulin in adult colonic myenteric ganglia was noted in the MFGM intervention non-separated group. In conclusion, dietary supplementation with MFGM from birth is sufficient to block MS-induced visceral hypersensitivity, highlighting its potential value in visceral pain-associated disorders, but future studies are required to fully elucidate the mechanistic role of this supplementation on MS-induced visceral pain.

Bifidobacterium longum counters the effects of obesity: Partial successful translation from rodent to human.

BACKGROUND: The human gut microbiota has emerged as a key factor in the development of obesity. Certain probiotic strains have shown anti-obesity effects. The objective of this study was to investigate whether Bifidobacterium longum APC1472 has anti-obesity effects in high-fat diet (HFD)-induced obese mice and whether B. longum APC1472 supplementation reduces body-mass index (BMI) in healthy overweight/obese individuals as the primary outcome. B. longum APC1472 effects on waist-to-hip ratio (W/H ratio) and on obesity-associated plasma biomarkers were analysed as secondary outcomes. METHODS: B. longum APC1472 was administered to HFD-fed C57BL/6 mice in drinking water for 16 weeks. In the human intervention trial, participants received B. longum APC1472 or placebo supplementation for 12 weeks, during which primary and secondary outcomes were measured at the beginning and end of the intervention. FINDINGS: B. longum APC1472 supplementation was associated with decreased bodyweight, fat depots accumulation and increased glucose tolerance in HFD-fed mice. While, in healthy overweight/obese adults, the supplementation of B. longum APC1472 strain did not change primary outcomes of BMI (0.03, 95% CI [-0.4, 0.3]) or W/H ratio (0.003, 95% CI [-0.01, 0.01]), a positive effect on the secondary outcome of fasting blood glucose levels was found (-0.299, 95% CI [-0.44, -0.09]). INTERPRETATION: This study shows a positive translational effect of B. longum APC1472 on fasting blood glucose from a preclinical mouse model of obesity to a human intervention study in otherwise healthy overweight and obese individuals. This highlights the promising potential of B. longum APC1472 to be developed as a valuable supplement in reducing specific markers of obesity. FUNDING: This research was funded in part by Science Foundation Ireland in the form of a Research Centre grant (SFI/12/RC/2273) to APC Microbiome Ireland and by a research grant from Cremo S.A.

Nutraceuticals to promote neuronal plasticity in response to corticosterone-induced stress in human neuroblastoma cells.

Objectives: To search for novel compounds that will protect neuronal cells under stressed conditions that may help to restore neuronal plasticity. Methods: A model of corticosterone (CORT)-induced stress in human neuroblastoma cells (SH-SY5Y) was used to compare the efficacy of 6 crude extracts and 10 pure compounds (6 polyphenols, 2 carotenoids, 1 amino acid analogue, and 1 known antidepressant drug) to increase neuronal plasticity and to decrease cytotoxicity. Results: Astaxanthin (among pure compounds) and phlorotannin extract of Fucus vesiculosus (among crude extracts) showed a maximum increase in cell viability in the presence of excess CORT. BDNF-VI mRNA expression in SH-SY5Y cells was significantly improved by pretreatment with quercetine, astaxanthin, curcumin, fisetin, and resveratrol. Among crude extracts, xanthohumol, phlorotannin extract (Ecklonia cava), petroleum ether extract (Nannochloropsis oculata), and phlorotannin extract (F. vesiculosus) showed a significant increase in BDNF-VI mRNA expression. CREB1 mRNA expression was significantly improved by astaxanthin, ß-carotene, curcumin, and fluoxetine whereas none of the crude extracts caused significant improvement. As an adjunct of fluoxetine, phlorotannin extract (F. vesiculosus), ß-carotene, and xanthohumol have resulted in significant improvement in BDNF-VI mRNA expression and CREB1 mRNA expression was significantly improved by phlorotannin extract (F. vesiculosus). Significant improvement in mature BDNF protein expression by phlorotannin extract (F. vesiculosus) and ß-carotene as an adjunct of fluoxetine confirm their potential to promote neuronal plasticity against CORT-induced stress. Discussion: The carotenoids, flavonoids, namely quercetine, curcumin, and low molecular weight phlorotannin-enriched extract of F. vesiculosus may serve as potential neuroprotective agents promoting neuronal plasticity in vitro. Graphical abstract: Cascade of events associated with disturbed homeostatic balance of glucocorticoids and impact of phlorotannin extract (F. vesiculosus) and ß-carotene in restoring neuronal plasticity. Abbreviation: TrKB, tropomyosin receptor kinase B; P-ERK, phosphorylated extracellular signal-related kinase; PI3K, phosphatidylinositol 3-kinase; Akt, protein kinase B; Ca++/CaMK, calcium/calmodulin-dependent protein kinase; pCREB, phosphorylated cAMP response element-binding protein; CRE, cAMP response elements, CORT, corticosterone; and BDNF; brain-derived neurotrophic factor.

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.

Deficiency of essential dietary n-3 PUFA disrupts the caecal microbiome and metabolome in mice.

n-3 PUFA are lipids that play crucial roles in immune-regulation, cardio-protection and neurodevelopment. However, little is known about the role that these essential dietary fats play in modulating caecal microbiota composition and the subsequent production of functional metabolites. To investigate this, female C57BL/6 mice were assigned to one of three diets (control (CON), n-3 supplemented (n3+) or n-3 deficient (n3-)) during gestation, following which their male offspring were continued on the same diets for 12 weeks. Caecal content of mothers and offspring were collected for 16S sequencing and metabolic phenotyping. n3- male offspring displayed significantly less % fat mass than n3+ and CON. n-3 Status also induced a number of changes to gut microbiota composition such that n3- offspring had greater abundance of Tenericutes, Anaeroplasma and Coriobacteriaceae. Metabolomics analysis revealed an increase in caecal metabolites involved in energy metabolism in n3+ including α-ketoglutaric acid, malic acid and fumaric acid. n3- animals displayed significantly reduced acetate, butyrate and total caecal SCFA production. These results demonstrate that dietary n-3 PUFA regulate gut microbiota homoeostasis whereby n-3 deficiency may induce a state of disturbance. Further studies are warranted to examine whether these microbial and metabolic disturbances are causally related to changes in metabolic health outcomes.

Bifidobacterium breve with α-linolenic acid alters the composition, distribution and transcription factor activity associated with metabolism and absorption of fat.

This study focused on the mechanisms that fatty acid conjugating strains - Bifidobacterium breve NCIMB 702258 and Bifidobacterium breve DPC 6330 - influence lipid metabolism when ingested with α-linolenic acid (ALA) enriched diet. Four groups of BALB/c mice received ALA enriched diet (3% (w/w)) either alone or in combination with B. breve NCIMB 702258 or B. breve DPC 6330 (109 CFU/day) or unsupplemented control diet for six weeks. The overall n-3 PUFA score was increased in all groups receiving the ALA enriched diet. Hepatic peroxisomal beta oxidation increased following supplementation of the ALA enriched diet with B. breve (P < 0.05) and so the ability of the strains to produce c9t11 conjugated linoleic acid (CLA) was identified in adipose tissue. Furthermore, a strain specific effect of B. breve NCIMB 702258 was found on the endocannabinoid system (ECS). Liver triglycerides (TAG) were reduced following ALA supplementation, compared with unsupplemented controls (P < 0.01) while intervention with B. breve further reduced liver TAG (P < 0.01), compared with the ALA enriched control. These data indicate that the interactions of the gut microbiota with fatty acid metabolism directly affect host health by modulating n-3 PUFA score and the ECS.

Microbes, Immunity, and Behavior: Psychoneuroimmunology Meets the Microbiome.

There is now a large volume of evidence to support the view that the immune system is a key communication pathway between the gut and brain, which plays an important role in stress-related psychopathologies and thus provides a potentially fruitful target for psychotropic intervention. The gut microbiota is a complex ecosystem with a diverse range of organisms and a sophisticated genomic structure. Bacteria within the gut are estimated to weigh in excess of 1 kg in the adult human and the microbes within not only produce antimicrobial peptides, short chain fatty acids, and vitamins, but also most of the common neurotransmitters found in the human brain. That the microbial content of the gut plays a key role in immune development is now beyond doubt. Early disruption of the host-microbe interplay can have lifelong consequences, not just in terms of intestinal function but in distal organs including the brain. It is clear that the immune system and nervous system are in continuous communication in order to maintain a state of homeostasis. Significant gaps in knowledge remain about the effect of the gut microbiota in coordinating the immune-nervous systems dialogue. However, studies using germ-free animals, infective models, prebiotics, probiotics, and antibiotics have increased our understanding of the interplay. Early life stress can have a lifelong impact on the microbial content of the intestine and permanently alter immune functioning. That early life stress can also impact adult psychopathology has long been appreciated in psychiatry. The challenge now is to fully decipher the molecular mechanisms that link the gut microbiota, immune, and central nervous systems in a network of communication that impacts behavior patterns and psychopathology, to eventually translate these findings to the human situation both in health and disease. Even at this juncture, there is evidence to pinpoint key sites of communication where gut microbial interventions either with drugs or diet or perhaps fecal microbiota transplantation may positively impact mental health.

Omega-3 polyunsaturated fatty acids critically regulate behaviour and gut microbiota development in adolescence and adulthood.

BACKGROUND: Neurodevelopment is strongly influenced by maternal and early-postnatal diet. Omega-3 polyunsaturated fatty acids (n-3 PUFA) are vital structural and functional components of the developing brain. The gut microbiota is also influenced by n-3 PUFA status, however, little is known about the role of maternal and early-life n-3 PUFA intake on offspring gut microbiota development and subsequent interactions with central nervous system functioning and behavioural outcomes. METHODS: Pregnant female C57BL/6 mice and their male offspring were fed a control (CON), omega-3 deficient (O3-) or omega-3 supplemented (O3+) diet. Cognitive, depressive and social behaviours were assessed through a battery of behaviour tests in the male offspring at both adolescence (week 4-5) and adulthood (week 11-13). Hypothalamic-pituitary-adrenal axis (HPA) activation was assessed by analysis of stress-induced corticosterone production. Fecal microbiota composition was analysed by 16S sequencing at both adolescent and adulthood. In addition, stimulated spleen cytokine levels were assessed. RESULTS: n-3 PUFA interventions induced subtle changes in offspring early-life and adolescent behaviours, which were further evident in adulthood, such that O3- animals displayed impaired communication, social and depression-related behaviours and O3+ animals displayed enhanced cognition. O3- mice displayed an elevated Firmicutes:Bacteroidetes ratio and blunted systemic LPS responsiveness. Contrastingly, O3+ mice displayed greater fecal Bifidobacterium and Lactobacillus abundance and dampened HPA-axis activity. CONCLUSIONS: Neurobehavioural development related to cognitive, anxiety and social behaviours, is highly dependent upon in utero and lifelong n-3 PUFA availability. In addition, neurobehavioural changes induced by altering n-3 PUFA status are closely associated with comprehensive alterations in gut microbiota composition, HPA-axis activity and inflammation.

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.

n-3 PUFAs have beneficial effects on anxiety and cognition in female rats: Effects of early life stress.

Stressful life events, especially those in early life, can exert long-lasting changes in the brain, increasing vulnerability to mental illness especially in females. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) play a critical role in the development and function of the central nervous system (CNS). Thus, we investigated the influence of an eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) (80% EPA, 20% DHA) n-3 PUFAs mixture on stress-related behavioural and neurobiological responses. Sprague-Dawley female rats were subjected to an early-life stress, maternal separation (MS) procedure from postnatal days 2 to 12. Non-separated (NS) and MS rats were administered saline, EPA/DHA 0.4g/kg/day or EPA/DHA 1g/kg/day, respectively. In adulthood, EPA/DHA treated animals had a dose dependent reduction in anxiety in NS rats. Furthermore, cognitive performance in the novel object recognition task (NOR) was improved by EPA/DHA treatment in NS animals only. EPA/DHA 1g/kg/day decreased behavioural despair in the forced swim test. Notably, EPA/DHA high dose increased the translocation of GRs into the nucleus of NS rat hippocampus. However, the levels of mBDNF remained unchanged in all the experimental groups. The corticosterone response to an acute stress was blunted in MS rats and this was further attenuated by pre-treatment with EPA/DHA. Immune response and monoamine neurotransmission were significantly altered by early-life stress. In conclusion, our study supports the view that n-3 PUFAs are beneficial in neurodevelopmentally normal animals but have little positive benefit in animals exposed to early life stress.

Ghrelin's Orexigenic Effect Is Modulated via a Serotonin 2C Receptor Interaction.

Understanding the intricate pathways that modulate appetite and subsequent food intake is of particular importance considering the rise in the incidence of obesity across the globe. The serotonergic system, specifically the 5-HT2C receptor, has been shown to be of critical importance in the regulation of appetite and satiety. The GHS-R1a receptor is another key receptor that is well-known for its role in the homeostatic control of food intake and energy balance. We recently showed compelling evidence for an interaction between the GHS-R1a receptor and the 5-HT2C receptor in an in vitro cell line system heterologously expressing both receptors. Here, we investigated this interaction further. First, we show that the GHS-R1a/5-HT2C dimer-induced attenuation of calcium signaling is not due to coupling to GαS, as no increase in cAMP signaling is observed. Next, flow cytometry fluorescence resonance energy transfer (fcFRET) is used to further demonstrate the direct interaction between the GHS-R1a receptor and 5-HT2C receptor. In addition, we demonstrate colocalized expression of the 5-HT2C and GHS-R1a receptor in cultured primary hypothalamic and hippocampal rat neurons, supporting the biological relevance of a physiological interaction. Furthermore, we demonstrate that when 5-HT2C receptor signaling is blocked ghrelin's orexigenic effect is potentiated in vivo. In contrast, the specific 5-HT2C receptor agonist lorcaserin, recently approved for the treatment of obesity, attenuates ghrelin-induced food intake. This underscores the biological significance of our in vitro findings of 5-HT2C receptor-mediated attenuation of GHS-R1a receptor activity. Together, this study demonstrates, for the first time, that the GHS-R1a/5-HT2C receptor interaction translates into a biologically significant modulation of ghrelin's orexigenic effect. This data highlights the potential development of a combined GHS-R1a and 5-HT2C receptor treatment strategy in weight management.

Dietary trans-10, cis-12-conjugated linoleic acid alters fatty acid metabolism and microbiota composition in mice.

The main aim of the present study was to investigate the effects of dietary trans-10, cis-12-conjugated linoleic acid (t10c12-CLA) on intestinal microbiota composition and SCFA production. C57BL/6 mice (n 8 per group) were fed a standard diet either supplemented with t10c12-CLA (0·5 %, w/w) (intervention) or with no supplementation (control), daily for 8 weeks. Metabolic markers (serum glucose, leptin, insulin and TAG, and liver TAG) were assessed by ELISA commercial kits, tissue long-chain fatty acids and caecal SCFA by GC, and microbial composition by 16S rRNA pyrosequencing. Dietary t10c12-CLA significantly decreased visceral fat mass (P< 0·001), but did not affect body weight (intervention), when compared with no supplementation (control). Additionally, lipid mass and composition were affected by t10c12-CLA intake. Caecal acetate, propionate and isobutyrate concentrations were higher (P< 0·05) in the t10c12-CLA-supplemented group than in the control group. The analysis of the microbiota composition following 8 weeks of t10c12-CLA supplementation revealed lower proportions of Firmicutes (P= 0·003) and higher proportions of Bacteroidetes (P= 0·027) compared with no supplementation. Furthermore, t10c12-CLA supplementation for 8 weeks significantly altered the gut microbiota composition, harbouring higher proportions of Bacteroidetes, including Porphyromonadaceae bacteria previously linked with negative effects on lipid metabolism and induction of hepatic steatosis. These results indicate that the mechanism of dietary t10c12-CLA on lipid metabolism in mice may be, at least, partially mediated by alterations in gut microbiota composition and functionality.

A natural solution for obesity: bioactives for the prevention and treatment of weight gain. A review.

OBJECTIVES: Obesity and obesity-related disorders are reaching epidemic proportions worldwide. In this review, we summarize the accumulating studies that have emerged in the last few decades demonstrating that bioactives from different natural sources could potentially have anti-obesity effects. METHODS: We carried out an extensive search of relevant literature from Pubmed, Web of Knowledge, and other online databases for studies where anti-obesity effects were shown by compounds from natural sources. RESULTS: Appetite suppression, lipid metabolism regulation, and increase of energy expenditure are the main mechanisms by which anti-obesity effects are exerted. Plants represent the most studied natural source of anti-obesity bioactives. Camellia sinensis is the most representative species exerting several anti-obesity effects. Moreover, probiotics (bacteria which bestow health benefit), such as strains of Bifidobacteria and Lactobacillus families, and certain prebiotics (non-viable food components that confers a health benefit on the host associated with modulation of the microbiota effects), such as insulin-type fructans, have also shown capability to combat obesity. Finally, compounds from animal sources, in particular bioactive peptides derived from milk-derived whey and casein protein digestion, high dietary calcium, and omega-3s polyunsaturated fatty acids (n-3 PUFA) present in fish oils, have also shown potential anti-obesity effects. DISCUSSION: Several anti-obesity effects have been observed in different natural bioactives providing an interesting and potentially safer and more desirable treatment strategy for the development of anti-obesity functional or medical foods.

Gut microbiota, the pharmabiotics they produce and host health.

A healthy gut microbiota plays many crucial functions in the host, being involved in the correct development and functioning of the immune system, assisting in the digestion of certain foods and in the production of health-beneficial bioactive metabolites or 'pharmabiotics'. These include bioactive lipids (including SCFA and conjugated linoleic acid) antimicrobials and exopolysaccharides in addition to nutrients, including vitamins B and K. Alterations in the composition of the gut microbiota and reductions in microbial diversity are highlighted in many disease states, possibly rendering the host susceptible to infection and consequently negatively affecting innate immune function. Evidence is also emerging of microbially produced molecules with neuroactive functions that can have influences across the brain-gut axis. For example, γ-aminobutyric acid, serotonin, catecholamines and acetylcholine may modulate neural signalling within the enteric nervous system, when released in the intestinal lumen and consequently signal brain function and behaviour. Dietary supplementation with probiotics and prebiotics are the most widely used dietary adjuncts to modulate the gut microbiota. Furthermore, evidence is emerging of the interactions between administered microbes and dietary substrates, leading to the production of pharmabiotics, which may directly or indirectly positively influence human health.

Devil's Claw to suppress appetite--ghrelin receptor modulation potential of a Harpagophytum procumbens root extract.

Ghrelin is a stomach-derived peptide that has been identified as the only circulating hunger hormone that exerts a potent orexigenic effect via activation of its receptor, the growth hormone secretagogue receptor (GHS-R1a). Hence, the ghrelinergic system represents a promising target to treat obesity and obesity-related diseases. In this study we analysed the GHS-R1a receptor activating potential of Harpagophytum procumbens, popularly known as Devil's Claw, and its effect on food intake in vivo. H. procumbens is an important traditional medicinal plant from Southern Africa with potent anti-inflammatory and analgesic effects. This plant has been also used as an appetite modulator but most evidences are anecdotal and to our knowledge, no clear scientific studies relating to appetite modulation have been done to this date. The ghrelin receptor activation potential of an extract derived from the dried tuberous roots of H. procumbens was analysed by calcium mobilization and receptor internalization assays in human embryonic kidney cells (Hek) stably expressing the GHS-R1a receptor. Food intake was investigated in male C57BL/6 mice following intraperitoneal administration of H. procumbens root extract in ad libitum and food restricted conditions. Exposure to H. procumbens extract demonstrated a significant increased cellular calcium influx but did not induce subsequent GHS-R1a receptor internalization, which is a characteristic for full receptor activation. A significant anorexigenic effect was observed in male C57BL/6 mice following peripheral administration of H. procumbens extract. We conclude that H. procumbens root extract is a potential novel source for potent anti-obesity bioactives. These results reinforce the promising potential of natural bioactives to be developed into functional foods with weight-loss and weight maintenance benefits.

Strain differences in stress-induced changes in central CRF1 receptor expression.

The Wistar Kyoto (WKY) rat is genetically predisposed to increased sensitivity to psychological and physical stressors. Evidence points towards the importance of corticotropin-releasing factor (CRF), a peptide secreted by the paraventricular nucleus of the hypothalamus, in this strain's aberrant response to stress. CRF binds to CRF1 and 2 receptors (CRFR1 and CRFR2) which are expressed in both hypothalamic and extra-hypothalamic brain regions. Phosphorylation of the signal transduction molecule, extracellular signal regulated kinase (ERK)1/2 has been linked with stress and the actions of CRF. Western blotting techniques were employed to examine changes in protein expression of CRFR1 and phosphorylated ERK1/2 in hypothalamic and extra-hypothalamic brain regions of open field-stressed Sprague Dawley (SD) and WKY rats. Stress exposure resulted in increased hypothalamic ERK1/2 phosphorylation and subsequent increases in CRFR1 expression in SD but not WKY rats. In extra-hypothalamic brain regions, the stressor caused decreased or unchanged ERK 1/2 phosphorylation in both strains. A potentiated increase in CRFR1 expression was noted in the frontal cortex of WKY rats following the stressor and expression of CRFR1 was reduced in the hippocampus of WKY rats. These data demonstrate region-specific differences in stress-induced changes in expression of CRF receptors and intracellular signaling molecules in stress-sensitive WKY rats and stress-resilient SD rats.

Bifidobacterium breve with α-linolenic acid and linoleic acid alters fatty acid metabolism in the maternal separation model of irritable bowel syndrome.

The aim of this study was to compare the impact of dietary supplementation with a Bifidobacterium breve strain together with linoleic acid & α-linolenic acid, for 7 weeks, on colonic sensitivity and fatty acid metabolism in rats. Maternally separated and non-maternally separated Sprague Dawley rats (n = 15) were orally gavaged with either B. breve DPC6330 (10(9) microorganisms/day) alone or in combination with 0.5% (w/w) linoleic acid & 0.5% (w/w) α-linolenic acid, daily for 7 weeks and compared with trehalose and bovine serum albumin. Tissue fatty acid composition was assessed by gas-liquid chromatography and visceral hypersensitivity was assessed by colorectal distension. Significant differences in the fatty acid profiles of the non-separated controls and maternally separated controls were observed for α-linolenic acid and arachidonic acid in the liver, oleic acid and eicosenoic acid (c11) in adipose tissue, and for palmitoleic acid and docosahexaenoic acid in serum (p<0.05). Administration of B. breve DPC6330 to MS rats significantly increased palmitoleic acid, arachidonic acid and docosahexaenoic acid in the liver, eicosenoic acid (c11) in adipose tissue and palmitoleic acid in the prefrontal cortex (p<0.05), whereas feeding B. breve DPC6330 to non separated rats significantly increased eicosapentaenoic acid and docosapentaenoic acid in serum (p<0.05) compared with the NS un-supplemented controls. Administration of B. breve DPC6330 in combination with linoleic acid and α-linolenic acid to maternally separated rats significantly increased docosapentaenoic acid in the serum (p<0.01) and α-linolenic acid in adipose tissue (p<0.001), whereas feeding B. breve DPC6330 with fatty acid supplementation to non-separated rats significantly increased liver and serum docosapentaenoic acid (p<0.05), and α-linolenic acid in adipose tissue (p<0.001). B. breve DPC6330 influenced host fatty acid metabolism. Administration of B. breve DPC6330 to maternally separated rats significantly modified the palmitoleic acid, arachidonic acid and docosahexaenoic acid contents in tissues. The effect was not observed in non-separated animals.

Contrasting effects of Bifidobacterium breve NCIMB 702258 and Bifidobacterium breve DPC 6330 on the composition of murine brain fatty acids and gut microbiota.

BACKGROUND: We previously showed that microbial metabolism in the gut influences the composition of bioactive fatty acids in host adipose tissue. OBJECTIVE: This study compared the effect of dietary supplementation for 8 wk with human-derived Bifidobacterium breve strains on fat distribution and composition and the composition of the gut microbiota in mice. METHODS: C57BL/6 mice (n = 8 per group) received B. breve DPC 6330 or B. breve NCIMB 702258 (10(9) microorganisms) daily for 8 wk or no supplement (controls). Tissue fatty acid composition was assessed by gas-liquid chromatography while 16S rRNA pyrosequencing was used to investigate microbiota composition. RESULTS: Visceral fat mass and brain stearic acid, arachidonic acid, and DHA were higher in mice supplemented with B. breve NCIMB 702258 than in mice in the other 2 groups (P < 0.05). In addition, both B. breve DPC 6330 and B. breve NCIMB 702258 supplementation resulted in higher propionate concentrations in the cecum than did no supplementation (P < 0.05). Compositional sequencing of the gut microbiota showed a tendency for greater proportions of Clostridiaceae (25%, 12%, and 18%; P = 0.08) and lower proportions of Eubacteriaceae (3%, 12%, and 13%; P = 0.06) in mice supplemented with B. breve DPC 6330 than in mice supplemented with B. breve NCIMB 702258 and unsupplemented controls, respectively. CONCLUSION: The response of fatty acid metabolism to administration of bifidobacteria is strain-dependent, and strain-strain differences are important factors that influence modulation of the gut microbial community by ingested microorganisms.

Diet-induced obesity blunts the behavioural effects of ghrelin: studies in a mouse-progressive ratio task.

RATIONAL: The ghrelinergic system is implicated in the development of obesity and in modulating central reward systems. It has been reported that diet-induced obesity causes blunted responding on food intake to ghrelin administration, associated with central ghrelin resistance. Here we investigate whether the stimulatory effects of ghrelin on the reward system are altered in diet-induced obese mice. METHODS: Obesity was induced in C57BL/6J mice by feeding high-fat diet for 13 weeks. Mice were trained in an operant fixed and exponential progressive ratio task to respond for sucrose rewards. In an ad libitum fed state, ghrelin and a ghrelin receptor antagonist were administered in the progressive ratio. Alterations in the central ghrelin system in diet-induced obese mice were assessed. RESULTS: Obese mice showed attenuated acquisition and performance in the fixed and progressive ratio paradigm. Most importantly, diet-induced obesity inhibited the stimulatory effects of ghrelin (2 nmol, 3 nmol/10 g) on progressive ratio responding whereas lean animals presented with increased responding. Administration of the ghrelin-receptor antagonist (D-Lys(3))-GHRP-6 (66.6 nmol/10 g) decreased performance in lean but not obese mice. This insensitivity to ghrelin receptor ligands in mice on high-fat diet was further supported by decreased mRNA expression of the ghrelin receptor in the hypothalamus and the nucleus accumbens in obese mice. CONCLUSIONS: This study demonstrates that the modulatory effects of ghrelin receptor ligands are blunted in a mouse model of diet-induced obesity in a progressive ratio task. Thereby, our data extend the previously described ghrelin resistance in these mice from food intake to reward-associated behaviours.