11 healthy subjects
|
Fecal sample analysis via 16S rRNA |
Microbiota composition may change based on diet. |
David et al. [23] |
Wistar rats
|
Feeding patterns, food preference, locomotor activity, and body temperature |
Olanzapine leads to increases in the levels of Firmicutes and decreases in the levels of Protobacteria and Actinobacteria. |
Davey et al. [26] |
Male Sprague Dawley rat pups
|
Endocrine and immune measurements, polymerase chain reaction of partial 16S ribosomal RNA gene fragments and analysis by denaturing gradient gel electrophoresis |
The stress caused by separation from the mother reduces the levels of Bifidobacteria and Lactobacilli in newborn rat guts. |
O’Mahony et al. [28] |
Male CD-1 mice
|
Social disruption tests, real-time PCR, bacterial tag-encoded FLX amplicon pyrosequencing |
Bacteroides species decrease and Clostridium species increase in the feces of mice that are exposed to chronic stress. |
Bailey et al. [29] |
Adult male Sprague-Dawley rats
|
Porsolt’s test, levels of components of the toll-like receptor 4 (TLR-4) signaling pathway, of lipopolysaccharide (LPS), and of different inflammatory, oxidative/nitrosative, and anti-inflammatory mediators were measured by RT-PCR, Western blot and/or ELISA in brain prefrontal cortex. |
Plasma LPS, LPS-binding protein, brain LPS receptor and TLR4 levels were found to be high. |
Garate et al. [30] |
871 European mothers and their children
|
Maternal interview, The Strengths and Difficulties Questionnaire, Conners Rating Scales Revised, The Centre for Epidemiological Studies Depression Scale for Children, intelligence tests |
Correlation between usage of antibiotics before the age of one year and adulthood depression. |
Slykerman et al. [31] |
NIH Swiss mice
|
Novel object recognition test, light/dark box test, acute restraint stress analysis, corticosterone immunoassay, DNA extraction, and high-throughput DNA sequencing |
Long-term usage of broad-spectrum antibiotics change gut microbiota composition permanently. |
Desbonnet et al. [32] |
Ninety-two patients with early stage schizophrenia
|
Scale for the Assessment of Negative Symptoms (SANS), Positive and Negative Syndrome Scale (PANSS), Clinical Global Impression Scale (CGI), and cognitive tests. |
Minocycline creates antipsychotic-like effect. |
Liu et al. [33] |
112 depressed patients and 28 normal controls
|
Hamilton Depression Rating Scale. Indirect ELISA method was employed to assay the immunoglobulin M (IgM) and IgA responses against the LPS of the commensal bacteria |
Due to leaky gut, endotoxins originated from microorganisms join the systemic circulation. |
Maes et al. [47] |
Female Wistar rats
|
Partial restraint stress tests, oral administration of Lactobacillus farciminis
|
Lactobacillus farciminis suppressed stress-induced hyperpermeability, endotoxemia and prevented hypothalamic–pituitary–adrenal (HPA) axis stress response and neuroinflammation. |
Ait-Belgnaoui et al. [48] |
Specific pathogen-free mice
|
Open field test, real-time PCR analysis to assess neuroinflammation, HPLC for analysis of 5-HT and 5-HIAA in brain and intestine |
In autistic mice, neuroinflammatory parameters increase. |
de Theije et al. [50] |
Pregnant C57BL/6N mice
|
Intestinal permeability assay, 16S rRNA gene sequence analysis, behavioral tests |
Autistic behaviors can be eliminated by adding Bacteroides fragilis to the microbiota. Bacteroides fragilis can repair leaky gut. |
Hsiao et al. [53] |
Male Wistar rats, healthy subjects
|
Hopkins Symptom Checklist-90, Hospital Anxiety and Depression Scale, Perceived Stress Scale, Coping Checklist, urinary free cortisol levels |
Lactobacillus helveticus and Bifidobacteria longum reduced the anxiety levels in rats and psychological distress in volunteers. |
Messaoudi et al. [54] |
Germ-free mice
|
Acute restraint test, maternal behavior observation |
Brain-derived neurotrophic factor (BDNF), N-methyl D-aspartate (NMDA) 2a levels decreased in the hippocampus of germ-free mice. |
Sudo et al. [63] |
Healthy volunteers
|
Hospital Anxiety and Depression Scale, Hopkins Symptoms Checklist, urinary free cortisol levels |
Anxiety levels recessed, and urine free cortisol levels decreased. |
Messaoudi et al. [64] |
37 depressed patients, and 18 non-depressed controls
|
Montgomery-Asberg Depression Rating Scale, Illumina deep sequencing of 16S rRNA gene amplicons |
Bacteroides levels are high and Lachnospiraceae levels are low in the stool of depression patients. |
Naseribafrouei et al. [72] |
Specific pathogen–free BALB/c mice, germ-free BALB/c mice
|
Levels of serotonin, noradrenaline, dopamine, and brain-derived neurotropic factor were assessed by enzyme-linked immunosorbent assay |
In germ-free mice BDNF levels and 5HT1A expression are low. |
Bercik et al. [80] |
Germ free mice, Specific pathogen-free mice
|
Elevated plus maze |
In germ-free mice anxiety levels are low. |
Neufeld et al. [90] |
Germ free mice
|
Open field test, elevated plus maze, light–dark box test |
Microbial colonization affects brain development and behavior. |
Diaz Heijtz et al. [92] |
Sprague–Dawley rat pups
|
Forced swim test, corticosterone enzyme immunoassay, brain monoamine analysis, plasma tryptophan pathway analysis |
Bifidobacterium infantis led to decreases in anxiety and depression levels and increases in central norepinephrine levels. |
Desbonnet et al. [94] |
Healthy male participants
|
Self-report stress measures, cognitive assessments, resting electroencephalography, plasma interleukin 10 (IL10), IL1β, IL6, IL8, and TNFα levels, whole blood toll-like receptor-4 agonist-induced cytokines, salivary cortisol analysis. |
Lactobacillus rhamnosus was not found to be superior to placebo. |
Kelly et al. [108] |
Patients with major depression and healthy subjects
|
Hamilton’s Depression Scale, Montgomery–Asberg Depression Rating Scale, Serum tumor necrosis factor-a, IL-1b, IL-6, brain-derived neurotrophic factor analysis, polymerase chain reaction and pyrosequencing |
Increases in the levels of Alistipes, Enterobacteriaceae Bacteroides, Proteobacteria and Actinobacteria and decreases in the levels of Faecalibacterium and Firmicutes in the fecal samples of depression patients. |
Jiang et al. [114] |
Male germ-free Kunming mice and Specific pathogen-free Kunming mice
|
Open-field test, Y-maze, tail suspension test, forced swimming test |
After stool transplantation from depression patients to germ-free mice started to show depression-like behaviors. |
Zheng et al. [116] |
Patients with major depression and healthy subjects, adult male Sprague-Dawley rats
|
Plasma C-reactive protein, panel of cytokines, salivary cortisol levels, plasma tryptophan and kynurenine, plasma lipopolysaccharide binding protein, 16sRNA metagenomic sequencing for fecal samples |
After fecal microbiota transplantation from depressed persons to rats, depression- and anxiety-like behaviors were observed in the laboratory animals. |
Kelly et al. [117] |