Maternal separation (MS) has been developed as a model for inducing stress and depression in studies using rodents. The concept of the gut-brain axis suggests that gut health is essential for brain health. Here, we present the effects of administration of a probiotic, Lactobacillus paracasei PS23 (PS23), to MS mice against psychological traits including anxiety and depression. The administration of live and heat-killed PS23 cells showed positive behavioural effects on MS animals, where exploratory tendencies and mobility were increased in behavioural tests, indicating reduced anxiety and depression compared to the negative control mice (P<0.05). Mice administered with both live and heat-killed PS23 cells also showed lower serum corticosterone levels accompanied by higher serum anti-inflammatory interleukin 10 (IL-10) levels, compared to MS separated mice (P<0.05), indicating a stress-elicited response affiliated with increased immunomodulatory properties. Assessment of neurotransmitters in the brain hippocampal region revealed that PS23 affected the concentrations of dopaminergic metabolites differently than the control, suggesting that PS23 may have improved MS-induced stress levels via neurotransmitter pathways, such as dopamine or other mechanisms not addressed in the current study. Our study illustrates the potential of a probiotic in reversing abnormalities induced by early life stress and could be an alternative for brain health along the gut-brain axis.
Probiotics have been reported to exert beneficial effects along the gut-brain axis. This randomised, double-blind and placebo-controlled human study aimed to evaluate such properties of Lactobacillus plantarum DR7 and its accompanying mechanisms in stressed adults. One hundred and eleven (n=111; DR7 n=56, placebo n=55) stressed adults were recruited based on moderate stress levels using the PSS-10 questionnaire. The consumption of DR7 (1×109 cfu/day) for 12 weeks reduced symptoms of stress (P=0.024), anxiety (P=0.001), and total psychological scores (P=0.022) as early as 8 weeks among stressed adults compared to the placebo group as assessed by the DASS-42 questionnaire. Plasma cortisol level was reduced among DR7 subjects as compared to the placebo, accompanied by reduced plasma pro-inflammatory cytokines, such as interferon-γ and transforming growth factor-α and increased plasma anti-inflammatory cytokines, such as interleukin 10 (P<0.05). DR7 better improved cognitive and memory functions in normal adults (>30 years old), such as basic attention, emotional cognition, and associate learning (P<0.05), as compared to the placebo and young adults (<30 years old). The administration of DR7 enhanced the serotonin pathway, as observed by lowered expressions of plasma dopamine β-hydroxylase (DBH), tyrosine hydroxylase (TH), indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase accompanied by increased expressions of tryptophan hydroxylase-2 and 5-hydroxytryptamine receptor-6, while stabilising the dopamine pathway as observed via stabilised expressions of TH and DBH over 12 weeks as compared to the placebo (P<0.05). Our results indicated that DR7 fulfil the requirement of a probiotic strain as per recommendation of FAO/WHO and could be applicable as a natural strategy to improve psychological functions, cognitive health and memory in stressed adults.
Individuals in a community who developed irritable bowel syndrome (IBS) after major floods have significant mental health impairment. We aimed to determine if Bifidobacterium infantis M-63 was effective in improving symptoms, psychology and quality of life measures in flood-affected individuals with IBS and if the improvement was mediated by gut microbiota changes. Design was non-randomised, open-label, controlled before-and-after. Of 53 participants, 20 with IBS were given B. infantis M-63 (1×109 cfu/sachet/day) for three months and 33 were controls. IBS symptom severity scale, hospital anxiety and depression scale, SF-36 Questionnaire, hydrogen breath testing for small intestinal bacterial overgrowth and stools for 16S rRNA metagenomic analysis were performed before and after intervention. 11 of 20 who were given probiotics (M-63) and 20 of 33 controls completed study as per-protocol. Mental well-being was improved with M-63 vs controls for full analysis (P=0.03) and per-protocol (P=0.01) populations. Within-group differences were observed for anxiety and bodily pain (both P=0.04) in the M-63 per-protocol population. Lower ratio of Firmicutes/Bacteroidetes was observed with M-63 vs controls (P=0.01) and the lower ratio was correlated with higher post-intervention mental score (P=0.04). B. infantis M-63 is probably effective in improving mental health of victims who developed IBS after floods and this is maybe due to restoration of microbial balance and the gut-brain axis. However, our conclusion must be interpreted within the context of limited sample size. The study was retrospectively registered on 12 October 2017 and the Trial Registration Number (TRN) was NCT03318614.
This 10-months randomised, double-blind, parallel and placebo-controlled study evaluated the effects of Bifidobacterium longum BB536 on diarrhoea and/or upper respiratory illnesses in 520 healthy Malaysian pre-school children aged 2-6 years old. The subjects randomly received a one-gram sachet containing either BB536 (5×109 cfu) or placebo daily. Data analysis was performed on 219 subjects who fully complied over 10-months (placebo n=110, BB536 n=109). While BB536 did not exert significant effects against diarrhoea in children, Poisson regression with generalised estimating equations model indicated significant intergroup difference in the mean number of times of respiratory illnesses over 10 months. The duration of sore throat was reduced by 46% (P=0.018), with marginal reduction for duration of fever (reduced by 27%, P=0.084), runny nose (reduced by 15%, P=0.087) and cough (reduced by 16%, P=0.087) as compared to the placebo. Principal coordinate analysis at genus level of the gut microbiota revealed significant differences between 0 and 10 months in the BB536 group (P<0.01) but not in placebo group (P>0.05). The abundance of the genus Faecalibacterium which is associated with anti-inflammatory and immuno-modulatory properties was significantly higher in the BB536 group (P<0.05) compared to the placebo group. Altogether, our present study illustrated the potential protective effects of BB536 against upper respiratory illnesses in pre-school Malaysian children, with gut microbiota modulating properties.
There is growing interest in the use of probiotic lactic acid bacteria (LAB) for prevention of hypercholesterolaemia. This study assessed the cholesterol lowering ability of Pediococcus acidilactici LAB4 and Lactobacillus plantarum LAB12 in growth media. Both LAB yielded >98% (39.2 μg/ml) cholesterol lowering in growth media. Nile Red staining indicated direct assimilation of cholesterol by the LAB. The LAB were then explored for their prophylactic (pre-treatment of HT29 cells with LAB prior to cholesterol exposure) and biotherapeutic (treatment of HT29 cells with LAB after exposure to cholesterol) use against short and prolonged exposure of HT29 cells to cholesterol, respectively. For HT29 cells pre-treated with LAB, cholesterol lowering was accompanied by down-regulation of ATP-binding cassette family transporter-type A1 (ABCA1), cluster of differentiation 36 (CD36) and scavenger receptor class B member 1 (SCARB1). HT29 cells treated with LAB after prolonged exposure to cholesterol source, on the other hand, was associated with up-regulation of ABCA1, restoration of CD36 to basal level and down-regulation of Neimann-Pick C1-Like 1 (NPC1L1). The present findings implied the potential use of LAB4 and LAB12 as part of the strategies in prevention and management of hypercholesterolaemia.
Increasing levels of antibiotic resistance by Staphylococcus aureus have posed a need to search for non-antibiotic alternatives. This study aimed to assess the inhibitory effects of crude and fractionated cell-free supernatants (CFS) of locally isolated lactic acid bacteria (LAB) against a clinical strain of S. aureus. A total of 42 LAB strains were isolated and identified from fresh vegetables, fresh fruits and fermented products prior to evaluation of inhibitory activities. CFS of LAB strains exhibiting a stronger inhibitive effect against S. aureus were fractionated into crude protein, polysaccharide and lipid fractions. Crude protein fractions showed greater inhibition against S. aureus compared to polysaccharide and lipid fractions, with a more prevalent effect from Lactobacillus plantarum 8513 and L. plantarum BT8513. Crude protein, polysaccharide and lipid fractions were also characterised with glycine, mannose and oleic acid being detected as the major component of each fraction, respectively. Scanning electron microscopy revealed roughed and wrinkled membrane morphology of S. aureus upon treatment with crude protein fractions of LAB, suggesting an inhibitory effect via the destruction of cellular membrane. This research illustrated the potential application of fractionated extracts from LAB to inhibit S. aureus for use in the food and health industry.
Probiotics are live microorganisms that confer health benefits through the gastrointestinal microbiota. This nutritional supplement may benefit athletes who undergo rigorous training by maintaining their gastrointestinal functions and overall health. In this study the influence of moderate physical exercise using a graded treadmill exercise, alone or in combination with the consumption of a soy product fermented with Lactobacillus plantarum LAB12 (LAB12), on tumour necrosis factor alpha (TNF-α) responses was investigated in a murine model. Male BALB/c mice were randomly divided into four groups of six mice each (control, exercise alone, LAB12 and LAB12 + exercise). Mice treated with the potential probiotic LAB12 were orally gavaged for 42 days. At autopsy, blood and spleen from the animals were collected. The splenocytes were cultured in the presence of a mitogen, concanavalin A (Con A). The amount of TNF-α produced by the Con A-stimulated splenocytes was quantified using ELISA, while their proliferation was determined using the [(3)H]-thymidine incorporation method. This study shows that LAB12-supplemented and exercise-induced mice showed marked increase (P<0.05) in cell proliferation compared to the control animals. TNF-α production was suppressed (P<0.05) in the LAB12 group compared to the untreated mice. These results demonstrate that supplementation with LAB12 has immunomodulatory effects, under conditions of moderate physical exercise, which may have implications for human athletes. Further investigation in human trials is warranted to confirm and extrapolate these findings.
The present study investigated the effects of Bifidobacterium longum BB536 on lipid profile, liver and kidney function, and body fat in hypercholesterolaemic rats. 40 Sprague-Dawley rats were randomly divided into five groups. The negative control group received a standard diet. The positive control group received a cholesterol-enriched diet, whereas the intervention groups received a cholesterol-enriched diet supplemented with B. longum BB536 alone or in combination with inulin or Mangifera pajang fibrous polysaccharides. After 8 weeks, plasma lipids, and liver and kidney function were tested. Intake of the cholesterol-enriched diet increased total cholesterol, alanine aminotransferase, gamma-glutamyl transferase, creatinine, urea, liver weight, adipose tissue weight, liver lipid deposition and adipocyte size. B. longum BB536 supplementation significantly reduced total cholesterol, liver lipid deposition and adipocyte size, and positively affected liver and kidney function. These effects were significantly increased in the presence of inulin and M. pajang fibrous polysaccharides.
Consumption of probiotics has been associated with decreased risk of colon cancer and reported to have antimutagenic/ anti-carcinogenic properties. One possible mechanism for this effect involves physical binding of the mutagenic compounds, such as heterocyclic amines (HCAs), to the bacteria. Therefore, the objective of this study was to examine the binding capacity of bifidobacterial strains of human origin on mutagenic heterocyclic amines which are suspected to play a role in human cancers. In vitro binding of the mutagens Trp-p-2, IQ, MeIQx, 7,8DiMeIQx and PhIP by three bacterial strains in two media of different pH was analysed using high performance liquid chromatography. Bifidobacterium pseudocatenulatum G4 showed the highest decrease in the total HCAs content, followed by Bifidobacterium longum, and Escherichia coli. pH affects binding capacity; the highest binding was obtained at pH 6.8. Gram-positive tested strains were found to be consistently more effective than the gram-negative strain. There were significant decreases in the amount of HCAs in the presence of different cell concentrations of B. pseudocatenulatum G4; the highest decrease was detected at the concentration of 10(10) cfu/ml. The results showed that HCAs were able to bind with all bacterial strains tested in vitro, thus it may be possible to decrease their absorption by human intestine and increase their elimination via faeces.