Bacteria in humans play an important role in health and disease. Considerable emphasis has been placed in understanding the role of bacteria in host-microbiome interkingdom communication. Here we show that serotonin, responsible for mood in the brain and motility in the gut, can also act as a bacterial signaling molecule for pathogenic bacteria. Specifically, we found that serotonin acts as an interkingdom signaling molecule via quorum sensing and that it stimulates the production of bacterial virulence factors and increases biofilm formation in vitro and in vivo in a novel mouse infection model. This discovery points out at roles of serotonin both in bacteria and humans, and at phenotypic implications not only manifested in mood behavior but also in infection processes in the host. Thus, regulating serotonin concentrations in the gut may provide with paradigm shifting therapeutic approaches."
Showing posts with label Mood disorder. Show all posts
Showing posts with label Mood disorder. Show all posts
Mild Infection May Raise Risk for Severe Mental Illness
"FLORENCE, Italy — Even mild infections significantly increase the risk of later developing schizophrenia and mood disorders, results of a large, population-based registry study indicate (from the Danish Register).
Regarding the prescribing of anti-infective medications as a proxy for mild infections, the team found that any prior prescription increased the risk for schizophrenia by 37% and the risk for mood disorders by 64%, fitting dose-response and temporal relationships."
Regarding the prescribing of anti-infective medications as a proxy for mild infections, the team found that any prior prescription increased the risk for schizophrenia by 37% and the risk for mood disorders by 64%, fitting dose-response and temporal relationships."
Fermented Food Linked to Mental Health | The Translational Microbiome Research Forum
"Recent research has investigated the intriguing link between mental health and the activity of the human gut’s microbiome, or the microorganisms that share our body space. These organisms outnumber our own cells by ten to one.
A team led by Eva M. Selhub, M.D., of Harvard Medical School and Massachusetts General Hospital, looked at the influence of fermented food and beverages.
They explain in the Journal of Physiological Anthropology that, “As our knowledge of the human microbiome increases, including its connection to mental health (for example, anxiety and depression), it is becoming increasingly clear that there are untold connections between our resident microbes and many aspects of physiology.”
Our intestine contains about 300 to 500 different species of bacteria that can be roughly divided into health-promoting ones, such as Bifidobacteria and Lactobacilli, and harmful ones such as Clostridia.
The team examined the history and application of fermentation “as a means to provide palatability, nutritional value, preservative, and medicinal properties.” This is an ancient practice that continues to the present day, they state.
In recent years, researchers have discovered many ways in which consuming fermented products affects our intestinal microbiota. For example, fermentation-enriched bioactive peptides, derived from whey milk protein, may have anti-inflammatory effects and reduce high blood pressure.
Selhub and colleagues put forward the argument that fermented food partly explains the link between traditional dietary practices and positive mental health.
The link could manifest itself directly through gut-to-brain communication, they say, or indirectly through beneficial bodily changes such as improved glycemic control antioxidant and anti-inflammatory activity, or reduction of intestinal permeability.
A further mechanism of action may be the influence of fermented food on endotoxins called lipopolysaccharide (LPS), large molecules that are found to be particularly important in depression. Lab tests on rodents and human volunteers show that even small increases in LPS levels can trigger depressive symptoms."
A team led by Eva M. Selhub, M.D., of Harvard Medical School and Massachusetts General Hospital, looked at the influence of fermented food and beverages.
They explain in the Journal of Physiological Anthropology that, “As our knowledge of the human microbiome increases, including its connection to mental health (for example, anxiety and depression), it is becoming increasingly clear that there are untold connections between our resident microbes and many aspects of physiology.”
Our intestine contains about 300 to 500 different species of bacteria that can be roughly divided into health-promoting ones, such as Bifidobacteria and Lactobacilli, and harmful ones such as Clostridia.
The team examined the history and application of fermentation “as a means to provide palatability, nutritional value, preservative, and medicinal properties.” This is an ancient practice that continues to the present day, they state.
In recent years, researchers have discovered many ways in which consuming fermented products affects our intestinal microbiota. For example, fermentation-enriched bioactive peptides, derived from whey milk protein, may have anti-inflammatory effects and reduce high blood pressure.
Selhub and colleagues put forward the argument that fermented food partly explains the link between traditional dietary practices and positive mental health.
The link could manifest itself directly through gut-to-brain communication, they say, or indirectly through beneficial bodily changes such as improved glycemic control antioxidant and anti-inflammatory activity, or reduction of intestinal permeability.
A further mechanism of action may be the influence of fermented food on endotoxins called lipopolysaccharide (LPS), large molecules that are found to be particularly important in depression. Lab tests on rodents and human volunteers show that even small increases in LPS levels can trigger depressive symptoms."
Molecular Psychiatry - Long-term inflammation increases risk of common mental disorder: a cohort study
These findings (based on repeated measures of IL6 over a period of time ) support the hypothesis that persistently elevated levels of IL-6 contribute to the development of common mental disorder.The fact that previous studies relied on a single measurement of IL-6 may partially explain the mixed findings: a one-off measure does not reliably capture the chronicity of inflammation. The present study has limitations: common mental disorder measured by a questionnaire is not the same as clinical diagnosis of depression or anxiety. Our data are from an occupational cohort where participants are likely to be healthier than the general population. Loss to follow-up accumulated over the extended follow-up; however, there was no evidence of major differences between the analytic sample and the sample at study recruitment.
Our findings have important clinical implications. If the observed association is causal, then targeting chronic inflammation with anti-inflammatory drugs could be useful in prevention of common mental disorder. Further studies are needed to clarify the underlying mechanisms, such as activation of the tryptophan-degrading enzyme, changes in indoleamine 2,3-dioxygenase, and abnormalities of the hypothalamic–pituitary–adrenal axis. Future investigations should also test the side effects, since anti-inflammatory strategies might increase the risk of infection and malignancy
Our findings have important clinical implications. If the observed association is causal, then targeting chronic inflammation with anti-inflammatory drugs could be useful in prevention of common mental disorder. Further studies are needed to clarify the underlying mechanisms, such as activation of the tryptophan-degrading enzyme, changes in indoleamine 2,3-dioxygenase, and abnormalities of the hypothalamic–pituitary–adrenal axis. Future investigations should also test the side effects, since anti-inflammatory strategies might increase the risk of infection and malignancy
Infections increase risk of mood disorders, study suggests
"New research shows that every third person who is diagnosed for the first time with a mood disorder has been admitted to hospital with an infection prior to the diagnosis. The study is the largest of its kind to date to show a clear correlation between infection levels and the risk of developing mood disorders."
Fetal exposure to excessive stress hormones in the womb linked to adult mood disorders
"Exposure of the developing fetus to excessive levels of stress hormones in the womb can cause mood disorders in later life and now, for the first time, researchers have found a mechanism that may underpin this process, according to research presented April 7 at the British Neuroscience Association Festival of Neuroscience (BNA2013) in London."
Aberrant light directly impairs mood and learning through melanopsin-expressing neurons : Nature : Nature Publishing Group
The daily solar cycle allows organisms to synchronize their circadian rhythms and sleep–wake cycles to the correct temporal niche. Changes in day-length, shift-work, and transmeridian travel lead to mood alterations and cognitive function deficits Sleep deprivation and circadian disruption underlie mood and cognitive disorders associated with irregular light schedules Whether irregular light schedules directly affect mood and cognitive functions in the context of normal sleep and circadian rhythms remains unclear. Here we show, using an aberrant light cycle that neither changes the amount and architecture of sleep nor causes changes in the circadian timing system, that light directly regulates mood-related behaviours and cognitive functions in mice. Animals exposed to the aberrant light cycle maintain daily corticosterone rhythms, but the overall levels of corticosterone are increased. Despite normal circadian and sleep structures, these animals show increased depression-like behaviours and impaired hippocampal long-term potentiation and learning. Administration of the antidepressant drugs fluoxetine or desipramine restores learning in mice exposed to the aberrant light cycle, suggesting that the mood deficit precedes the learning impairments. To determine the retinal circuits underlying this impairment of mood and learning, we examined the behavioural consequences of this light cycle in animals that lack intrinsically photosensitive retinal ganglion cells. In these animals, the aberrant light cycle does not impair mood and learning, despite the presence of the conventional retinal ganglion cells and the ability of these animals to detect light for image formation. These findings demonstrate the ability of light to influence cognitive and mood functions directly through intrinsically photosensitive retinal ganglion cells.
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