Dietary fibre inulin promotes allergy-related inflammation in lung, gut: Study
Title description, 2022-11-04
November 4, 2022
According to researchers, a type of dietary fibre called inulin, which is used in health supplements and have certain anti-inflammatory properties, can also promote an allergy-related type of inflammation in the lung and gut, as well as other parts of the body. Researchers from Friedman Centre for Nutrition and Inflammation and Jill Roberts Institute for Inflammatory Bowel Disease at Weill Cornell Medicine and in the Boyce Thompson Institute on Cornell"s Ithaca campus published their findings in the journal Nature.
The study found that dietary inulin fiber alters the metabolism of certain gut bacteria, which in turn triggers what scientists call type 2 inflammation in the gut and lungs. This type of inflammation is thought to have evolved in mammals chiefly to defend against parasitic worm ("helminth") infections, and is also part of normal wound-healing, although its inappropriate activation underlies allergies, asthma and other inflammatory diseases.
"There"s a lot to think about here, but, in general, these findings broaden our understanding of the relationship between diet, immunity, and the normally beneficial microorganisms that constitute our microbiota and colonize our bodies," said study co-senior author Dr David Artis, director of the Friedman Center for Nutrition and Inflammation and the Michael Kors Professor of Immunology at Weill Cornell Medicine.
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The study"s scientific participants reflect the Friedman Center"s highly cross-collaborative research mission, drawing on expertise in bacterial genetics, biochemistry and immunology at Weill Cornell Medicine in New York City and Cornell"s Ithaca campus. Dr Chun-Jun Guo, assistant professor of immunology in medicine at Weill Cornell Medicine, and Dr Frank Schroeder, professor at the Boyce Thompson Institute and in the Department of Chemistry and Chemical Biology in the College of Arts and Sciences on Cornell"s Ithaca campus teamed up with the Artis laboratory to gain a detailed understanding of how an important dietary component affects the microbiome and the immune response. The study"s first author is Dr Mohammad Arifuzzaman, a postdoctoral researcher in the Artis laboratory.Dr. Artis is also director of the Jill Roberts Institute for Inflammatory Bowel Disease at Weill Cornell Medicine.
Small amounts of inulin are present in a wide variety of fruits and vegetables, including bananas, asparagus, and garlic. It is also frequently concentrated in commonly available high-fiber dietary supplements. Previous studies have found that inulin boosts populations of beneficial gut bacterial species which in turn boost levels of anti-inflammatory immune cells called regulatory T (Treg) cells.
In this new study, the researchers examined inulin"s effects more comprehensively. They gave mice an inulin-based, high-fiber diet for two weeks, and then analysed the many differences between these mice and mice that had been fed a diet lacking inulin. A major difference was that the inulin diet, while increasing Treg cells, also induced markedly higher levels of white blood cells called eosinophils in the gut and lungs. A high level of eosinophils is a classic sign of type 2 inflammation and is typically seen in the setting of seasonal allergies and asthma.
Ultimately the researchers found that the eosinophil response was mediated by immune cells called group 2 innate lymphoid cells (ILC2s), which were activated by elevated levels of small molecules called bile acids in the blood. The bile acid levels were elevated due to the inulin-induced growth of certain bacterial species--a group called Bacteroidetes, found in both mice and humans--which have a bile acid-metabolizing enzyme.
"We were amazed to find such a strong association between inulin supplementation and increased bile acid levels," Dr Schroeder said. "We then found that deletion of the bile acid receptor abrogates the inulin-induced inflammation, suggesting that microbiota-driven changes in bile acid metabolism underlie the effects of inulin."
"When we colonized germ-free mice (mice without microbiota) with one of these bacterial species, and then knocked out the gene for one bacterial enzyme that promotes bile acid production, the whole pathway leading from inulin to eosinophilia and allergic inflammation was blocked," Dr Guo said.
The finding that inulin promotes type 2 inflammation does not mean that this type of fiber is always "bad," the researchers said. They found that inulin did worsen allergen-induced type 2 airway inflammation in mice. But the experiments also confirmed inulin"s previously reported effect at boosting anti-inflammatory Treg cells, which may in many cases, outweigh some pro-inflammatory impact. Moreover, a type 2 immune response, which in the gut and lungs involves an increased production of tissue-protecting mucus, is not necessarily harmful in healthy people--indeed, the researchers found in their mouse experiments that the inulin-induced type 2 inflammation enhances the defense against helminth infection.
"It could be that this inulin to type-2-inflammation pathway represents an adaptive, beneficial response to endemic helminth parasite infection, though its effects in a more industrialized, helminth-free environment are more complex and harder to predict," said Dr Arifuzzaman.
The researchers now plan to use their multi-disciplinary, multi-platform approach to study systematically the immune effects of the different types of dietary fiber as well as a range of other dietary supplements in different states of health and disease. (ANI)
Single dose of magic mushrooms helps treat depression in some, shows trial
Title description, 2022-11-04
November 4, 2022
Researchers have been looking into ways to treat depression with psilocybin for years. Although some studies have shown promising results, psychiatrists aren’t prescribing magic mushrooms as an antidepressant yet. Why? In short, they haven’t found enough evidence that any positive effects they’ve observed would be translatable to the wider population. (Also read: 8 positive things to tell a person struggling with depression)
But that’s changing. New trial results published Wednesday in the New England Journal of Medicine tested the effects of psilocybin in treating depression symptoms in 233 people. The results were encouraging — a single dose of the drug reduced depressive symptoms for three weeks in nearly a third of patients with treatment-resistant depression.
Psilocybin — often referred to as "shrooms" or magic mushrooms — induce a change in perception, hallucinations and euphoria, with effects lasting up to six hours. Magic mushrooms aren’t thought to cause addiction and can be safe in moderation if correctly distinguished from other more poisonous types of mushrooms.
Side effects common
Despite the positive results, the study authors offered a sobering conclusion to the study.
Negative side effects were very common, they wrote: During the six-hour psilocybin trip, 77% of people experienced some sort of negative response to the drug, including headache, nausea and dizziness.
More worryingly, a small number of patients experienced suicidal thoughts and ideation during the trip.
However, experts cast doubt on whether it was the psilocybin itself causing the suicidal thoughts, but rather the depression itself.
One question going forward is whether people can cope with the temporary effects of the trip for the long-term benefits to depressive symptoms.
In an accompanying editorial piece, study author Bertha Madras discussed the need for therapists to identify the right patients for the treatment, and to guide a person’s experience with psilocybin.
Magic mushrooms increase brain connectivity
But how does psilocybin help treat depression? In short: Researchers aren’t quite sure yet. But they have some ideas.
According to a study published April 2022 in the journal Nature Medicine, psilocybin appears to make the brain more interconnected.
The researchers analyzed the functional magnetic resonance imaging (fMRI) of patients with depression from two previous independent clinical trials using psilocybin therapy. An fMRI is a brain scan in which the active regions of the brain can be visualized on a computer screen.
The study found that in patients undergoing psilocybin treatment for depression, brain regions appeared to be more interconnected than before the treatment. This means that parts of the brain that had previously exhibited connectivity limited within isolated regions became more connected with other regions.
Researchers say that after taking psilocybin, these patients" brain connectivity became dispersed over the whole brain.
Despite this progress, scientists are still trying to understand what it means for people who suffer from depression. It is not clear, for example, how brain connectivity impacts a person’s well-being.
Matthias Liechti, a professor of clinical pharmacology at Switzerland’s University Hospital Basel and consultant for New York-based psychedelic medicine startup MindMed, suggests this interconnectivity “could correspond to a described subjective increased flexibility and emotional relaxation.”
But researchers are far from a consensus.
Still a long trip ahead
The positive effects of psilocybin and other psychedelic drugs like LSD and ayahuasca are not limited to depression. They have also shown promising results for treating anxiety, neuropsychiatric diseases and abuse of substances like morphine and alcohol.
Many groups are calling for the endorsement of psychedelic drugs as treatment options for psychological problems. Part of this is a political response to shape access in the wake of the ‘war on drugs’.
However, many experts are calling for moderation, emphasizing the need for rigorous medical studies to ensure the drugs are effective and safe to use.
Work is underway. Nearly 200 clinical trials are currently testing the effects of medical psychedelic drugs on a range of psychological and neuropsychiatric disorders. So far, the results are encouraging, but time will tell whether they make it into clinical practice.