Disease ⇒ Depression ⇒ Major depressive disorder {40000197}

Shared Reference Notes

• [1.1] 
  -The levels of fecal GABA and its relevant metabolites (N-acetylornithine, proline, oxoproline, and glutathione) were consistently decreased in MDD relative to HCs, suggesting a decrease in GABA content in the intestine. - A microbial enzyme–related gene (BetB) that participated in arginine metabolism to GABA was down-regulated in MDD. - Three microbial genes involved in the metabolism of glutamine to GABA was up-regulated in MDD. - Fecal GABA level in the patients with MDD may be modulated by a panel of gut microbes, which may be implicated in the development of MDD. - Majority of genes involved in the phenylalanine catabolic pathways were decreased in MDD, suggesting an inhibition of fecal phenylalanine degradation. - A downstream catabolic product of homovanillate was also decreased in MDD. These findings were consistent with disturbances of phenylalanine metabolism in MDD. - A gene (kynu) involved in kynurenic acid to quinolinic acid was enriched in MDD subjects relative to HCs, yielding an increased synthesis of the neurotoxic metabolite quinolinic acid. - A lower fecal quinolinic acid level in MDD. - These preliminary findings may account for the higher blood level of quinolinic acid observed in MDD. - Microbial GABA, phenylalanine, and quinolinic acid metabolisms were linked with MDD onset
• [1.2] 
  - Major depression and anxiety states, are common in patients presenting with irritable bowel syndrome (IBS)
• [1.3] 
  - Patients with major depressive disorder showed a statistically significant overrepresentation of #Bacteroides enterotype 2 compared to controls.
• [1.4] 
  - γ-aminobutyric acid (#GABA) production by human-derived #Bacteroides is widespread, and there is a correlation between brain signatures of #Depression and fecal #Bacteroides levels in patients with major depressive disorder
• - γ-aminobutyric acid (#GABA) production by human-derived #Bacteroides is widespread, and there is a correlation between brain signatures of depression and fecal #Bacteroides levels in patients with major depressive disorder.
• [1.5] 
  - MDD is associated with higher relative abundance of Clostridiales , OTU16802 Bacteroides and Prevotellaceae. - Similar association directions of for Blautia with MDD and SCZ. - Increased Bacilli is potentially associated with a higher risk of MDD, possibly involving dopamine metabolism which might play a role in the major symptoms of MDD. - Animal models found increased levels of Gammaproteobacteria were also associated with higher MDD risk and fluoxetine treatment was effective, implying strong correlations between gut microbiota and anxiety- and depression-like behaviors. (6)
• [1.6] 
  - Mendelian randomization analysis indicated a potential causal effect of #Morganella on major depressive disorder, consistent with observational incident
• [1.7] 
  - #Actinobacteria were found to be increased, whereas #Bacteroidetes were decreased in relation to other phyla, and some studies suggested decreased microbial diversity in MDD patients
• [1.8] 
  - a 37-year-old female diagnosed with perioral dermatitis treated with minocycline, who within 1 week suffered from severe depersonalization symptoms.
• [1.9] [#Bipolar disorder, #Schizophrenia] 
  - MDD was often characterized by higher #Alistipes and #Parabacteroides and lower #Prevotella; BD by higher #Bifidobacterium and #Oscillibacter; and SZ by higher #Prevotella and lower #Bacteroides, #Haemophilus, and #Streptococcus
• [#Bipolar disorder, #Schizophrenia] - Gut microbiota in BD, MDD and SZ > increase in #Eggerthella and #Lactobacillus, together with a decrease in #Coprococcus was common for the three conditions in comparison to controls.
• [#Bipolar disorder, #Schizophrenia] - MDD and SZ shared higher levels of #Escherichia/#Shigella and #Veillonella whereas increased #Megasphaera and lower #Roseburia are common for BD and SZ.
• [#Bipolar disorder, #Schizophrenia] [#Quinolinic acid, #kynurenine] - shift in the #Tryptophan metabolism from #Serotonin to the kyn pathway is associated with BD, MDD and SZ, but only in mood disorders (BD and MDD) there was a preferential metabolism of Kyn to the potentially neurotoxic QA.
• [#Bipolar disorder] [#Bifidobacterium infantis] - the abundance of #Fusobacteriaceae, #Escherichia blattae DSM 4481 and #Klebsiella oxytoca were significantly augmented, whereas the #Bifidobacterium longum subsp. infantis ATCC 15697 = JCM 1222 was significantly reduced in BD group compared with MDD group
• [#Bipolar disorder] - MDD and BD had more commonalities, including higher #Enterococcus, #Flavonifractor, and #Streptococcus, and lower #Faecalibacterium and #Ruminococcus.
• [#Bipolar disorder] - #Prevotella 2 and #Ruminococcaceae UCG-002 are more prevalent in patients with MDD than BD patients.
• [#Depression] [#Lipopolysaccharide] - elevated GIT permeability with an increased translocation of LPS from gram-negative bacteria plays a significant role in the pathophysiology of MDD
• [1.11] 
  - in MDD > Changes observed in lipoproteins, were consistent with the differential composition of gut microbiota belonging to the order #Clostridiales and the phyla #Proteobacteria/Pseudomonadota and #Bacteroidetes/#Bacteroidota.
• - #Citrate was significantly decreased and #Pyruvate was significantly increased in individuals with MDD.
• [1.12] 
  - abundance of #Enterobacteriaceae and #Alistipes was increased, and #Faecalibacterium abundance was decreased in patients with major depressive disorder
• [1.13] [#Depression] 
  - Microbial signals, pathological neurobiological changes, and depressive emotions can activate the HPA axis, increasing the synthesis and release of cortisol. - As a part of the brain-gut axis, excessive levels of cortisol promote gut pathology by modulating intestinal barrier function and inflammatory responses, resulting in a leaky gut
• [#Short Chain Fatty Acid] - SCFAs were reported to be depleted in patients with MDD,2,32 while their administration resulted in antidepressant effects by ameliorating #Depression-related intestinal permeability and hypothalamic–pituitary–adrenal (HPA) axis reactivity, in particular #Butyrate
• - Shifts in the composition of bacteriophages in MDD patients have been documented, particularly changes in #Caudovirales bacteriophages.
• - An increase in #Eggerthella and decrease in #Sutterella were also consistently demonstrated in patients with MDD.
• - the increasing abundances of #Morganella predicted to have a causal effect on MDD.
• - isolated #Mycobacterium neoaurum, which can degrade testosterone by expressing the 3β-Hydroxysteroid dehydrogenase enzyme, from the feces of male MDD patients, and found that administering this strain to rats via oral gavage, induced depressive-like behaviors.
• [1.14] [#Depression, #Schizophrenia] [#Candida albicans] 
• [1.15] [#Gender] 
  - Women with MDD display higher levels of #Actinobacteria compared to healthy women, whereas men with MDD exhibited lower levels of #Bacteroidetes.
• [1.16] [#Bacteroides ovatus, #Bacteroides thetaiotaomicron] 
  - MDD > An enzyme (α-L-arabinofuranosidase) in the GH51 family, encoded by two dominant Bacteroides (B. ovatus V975 and B. thetaiotaomicron VPI-5482)
• - gut microbiota of MDD have a greater mucin-utilization capacity relative to HC. It may because of the high concentration of #Bacteroides in MDD population.
• [#Bacteroides fragilis, #Bacteroides thetaiotaomicron] - the increased availability of mucin may weaken the mucous layer of the intestinal wall, and some #Bacteroides can degrade mucin during survival, such as B. thetaiotaomicron, B. fragilis, as a result, harmful molecules in MDD are more likely to cross the gut and enter the circulatory or endocrine system
• [#Bacteroides ovatus, #Bacteroides thetaiotaomicron] - #Bacteroides, especially #Bacteroides thetaiotaomicron and #Bacteroides ovatus, dedicate about 6% of their genomes to encode these two CAZymes. - These results suggesting that alternations of #Bacteroides species was a hallmark of MDD,
• - MDD was associated with enriched Glycoside Hydrolases and #Polysaccharide Lyases.
• [1.17] [#Parkinson’s Disease] 
  - #Isoprene is involved in the mevalonate pathway of #Cholesterol synthesis. - decreased exhaled levels of #Isoprene have been detected in patients with #Lung cancer. - #Isoprene > a key role in cell membrane integrity, which has been linked to several neurologic and psychiatric disorders, such as #Schizophrenia and #Bipolar disorder, as well as Parkinson disease and #Multiple Sclerosis. - A possible neuroprotective function of #Isoprene might explain its absence in the breath of patients with #Schizophrenia and MDD, indicating a disturbance in neuroprotection in psychiatric disorders.
• - significant downregulation of TAAR5 in the prefrontal cortex of patients with MDD, but no expression imbalances of TAAR5 for those with #Bipolar disorder or #Schizophrenia.

References Notes