Tag: gut microbiota

Categories : Gastrointestinal Mental HealthTags :

IBD and Depression is a Two-way Street

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Photo by Andrea Piacquadio on Pexels

While irritable bowel disease (IBD) and depression are known to occur together, scientists report a clinical overlap of these conditions in the Journal of Gastroenterology and Hepatology, implying the existence of a two-way relationship. Patients diagnosed with IBD were nine times as likely to develop depression than the general population. Their siblings who did not suffer from IBD were almost two times as likely to develop depression.

Conversely, patients with depression were two times as likely to develop IBD, and their siblings without depression were more than one and a half times as likely to develop IBD.

“This research reveals a clinical overlap between both conditions, and is the first study to investigate the two-way association between IBD and depression in siblings,” said Bing Zhang, MD, a gastroenterologist with Keck Medicine and co-lead author of the study.

The researchers drew on the data of more than 20 million people from Taiwan’s National Health Insurance Research Database. For 11 years, they tracked patients with either IBD or depression and their siblings without either condition, comparing onset of depression or IBD with a control group of people without either condition, but with similar age, sex and socioeconomic status.

Zhang hypothesises that many factors may contribute to the bidirectional nature of the disorders, including environmental stressors, the gut microbiome and genetics.

“The finding that people with IBD are more prone to depression makes sense because IBD causes constant gastrointestinal symptoms that can be very disruptive to a patient’s life,” he said. “And the elevated depression risk among siblings of IBD patients may reflect caregiver fatigue if the siblings have a role in caring for the patient.”

What surprised researchers was that patients with depression were prone to IBD. Zhang speculates that this discovery may have to do with what is known as the gut-brain axis, a scientifically established connection between the gastrointestinal system and the central nervous system, which consists of the spinal cord and the brain.

For example, he said, inflammation of the brain, which plays a role in depression, may be linked to the inflammation of the gastrointestinal tract, a hallmark of IBD.

The researchers are not sure why siblings of patients with depression are more likely to be diagnosed with IBD. Zhang surmises that there may be a shared genetic susceptibility for either disease that presents differently in family members.

Zhang hopes that the study findings will encourage health care professionals to take both family history and the relationship between gastrointestinal and mood disorders into consideration when evaluating or treating patients with either IBD or depression.

Through more research and better understanding of the gut-brain axis, he envisions leveraging the newfound connection between the conditions to improve the prevention, diagnosis and treatment of IBD and mental disorders.

Source: University of Southern California – Health Sciences

Categories : AntibioticsTags :

Faecal Microbiota Transplantation is Effective for Recurrent C. Diff

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C difficile. Source: CDC

Research just published in Clinical Infectious Diseases has found that Faecal Microbiota Transplantation, or FMT, is an optimal cost-effective treatment for first recurrent Clostridioides difficile infection (CDI).

“The most effective therapies for CDI are also the cost effective therapies,” said co-investigator Radha Rajasingham, MD. “FMT should be moved earlier in the treatment algorithm for CDI. Our model suggests it is effective and cost effective when used in patients after a single episode of recurrent CDI.”

Mathematical modelling was used to understand both the effectiveness and cost effectiveness of earlier use of FMT in the treatment of CDI, which normally arises from the disruption of healthy gut bacteria.

While this disease is caused by antibiotics, it is often treated with antibiotics, including fidaxomicin for initial, non-severe CDI or vancomycin for severe CDI, followed by FMT for any recurrent CDI.s. Unfortunately in many cases, CDI recurs in the same person again. This cycle of infection is called recurrent CDI.

Current guidelines recommend using FMT as a last resort for people with recurrent CDI. The goal of this research was to examine the benefits of using FMT earlier in the cycle of CDI.

“Based on this analysis, we would recommend that rather than waiting for multiple recurrent CDI, providers should consider FMT use for any recurrent CDI,” said co-author Byron Vaughn, MD, MS.

The authors suggest future research examine the role of FMT to prevent all recurrent CDI or even as primary prevention of CDI in high risk individuals.

Source: University of Minnesota Medical School

Categories : Antibiotics ExerciseTags :

Antibiotic Use Impedes Athletes’ Performance

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Tired woman after exercise
Photo by Ketut Subiyanto on Pexels

New research published in the journal Behavioural Processes demonstrates that by killing essential gut bacteria, antibiotics ravage athletes’ motivation and endurance. This study, which examined mice, suggests there is a big difference in the gut microbiome of athletes and couch potatoes.

Much research has been done on how exercise impacts the gut microbiome, but this study is one of few to examine the reverse – how gut bacteria also impact voluntary exercise behaviours. Engaging in voluntary exercise involves both motivation and athletic ability.

“We believed an animal’s collection of gut bacteria, its microbiome, would affect digestive processes and muscle function, as well as motivation for various behaviours, including exercise,” said Theodore Garland, UCR evolutionary physiologist in whose lab the research was conducted. “Our study reinforces this belief.”

Researchers confirmed through faecal samples that after 10 days of antibiotics, gut bacteria were reduced both in a group of ‘athletic’ mice bred for running on wheels and those that were not. Since no sickness behaviour was seen in the mice, exercise changes were ascribed solely to changes in antibiotic-induced changes in the gut bacteria.

Wheel running in the athletic mice was reduced by 21%, and the high runner mice did not recover their running behaviour even 12 days after the antibiotic treatment stopped.

Meanwhile, for the normal mice, antibiotics caused no difference in the running behaviour.

“A casual exerciser with a minor injury wouldn’t be affected much. But on a world-class athlete, a small setback can be much more magnified,” said Monica McNamara, UCR evolutionary biology doctoral student and the paper’s first author. “That’s why we wanted to compare the two types of mice.” Knocking out the normal gut microbiome might be compared with an injury.

One way the microbiome might affect exercise in mice or in humans is how carbohydrate metabolites are used by the muscles.

“Metabolic end products from bacteria in the gut can be reabsorbed and used as fuel,” Garland said. “Fewer good bacteria means less available fuel.”

The researchers would next like to identify the gut bacteria contributing to increased athletic performance. “If we can pinpoint the right microbes, there exists the possibility of using them as a therapeutic to help average people exercise more,” Garland said.

Lack of exercise is a risk factor for many diseases, and researchers would like to find ways of encouraging it more.

“Though we are studying mice, their physiology is very similar to humans. The more we learn from them, the better our chances of improving our own health,” Garland said.

Research into foods that can increase desirable gut bacteria is ongoing, and Garland recommends a balanced diet in addition to regular exercise to promote health.

Source: University of California, Riverside

Categories : Antibiotics Cardiovascular DiseaseTags :

Gut Bacteria can Reduce Effectiveness of Antihypertensive Drugs

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A new study published this month in the journal Hypertension has shown gut bacteria can reduce the effectiveness of certain antihypertensive drugs. The research provides the first clues into why some people not respond well to medication.

Among those with hypertension, an estimated 20% have resistant hypertension, where their blood pressure remains high despite aggressive treatment.

“The only thing doctors can really do in these patients is adding or switching medications and increasing the dose with the hope they can find something that works,” said Dr Tao Yang, an assistant professor at University of Toledo and the study’s first and lead author. “Until now, we haven’t had any clear indication what the mechanism is for resistant hypertension. Our research could provide a first step toward identifying new ways to effectively overcome treatment-resistant hypertension.”

Recent research has focused on the link between blood pressure and the gut microbiome. That work has helped to unravel potential causes of hypertension beyond diet and exercise. However, Dr Yang’s research is the first to examine the impact of gut bacteria on blood pressure medication itself.

In the study, UToledo scientists compared the effectiveness of the antihypertensive drug quinapril in rats with normal gut bacteria against those with gut microbiota depleted by high doses of antibiotics.

Researchers found a clear difference between the two, with animals that were given antibiotics first responding much better to quinapril.

Analysis of the gut bacteria composition in the animals identified the bacteria Coprococcus as the culprit. Laboratory experiments proved that Coprococcus comes, a dominant bacteria species in this genus, can break down quinapril and ramipril, resulting in the compromised blood pressure-lowering effects.

While the study was confined to animal models and lab experiments, researchers did find at least one intriguing case study that seems to support the notion that this could be applicable to humans.

That 2015 report, published in the International Journal of Cardiology, described a woman with a long history of treatment-resistant hypertension whose blood pressure was controlled without any antihypertensive medication for the two weeks she was taking antibiotics for a post-surgical infection. Her blood pressure was able to be controlled with only one medication for six months after stopping antibiotics, before again becoming treatment-resistant.

“This is just one report and more research is needed. However, this suggests that gut bacteria can play a very real and very important role in regulating the efficacy of blood pressure medication,” Dr Yang said.

The research group intends to further explore the interaction between additional blood pressure medications and other common types of gut bacteria.

Though long-term use of antibiotics isn’t a realistic strategy for addressing treatment-resistant hypertension, Dr Yang said it should be possible for someone to alter their microbiota through probiotics, prebiotics and changes in diet.

“The ultimate goal of my research is to identify ways we can specifically target the bacteria in an individual’s gut to improve drug efficacy,” he said. “This has the potential to benefit a lot of people.”

Source: University of Toledo

Categories : Allergies Obstetrics & GynaecologyTags :

No Food Allergy Link to Caesarean Delivery

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Man holding newborn baby
Photo by Jonathan Borba on Unsplash

A new study found that caesarean delivery, either with or without labour, or elective or emergency, compared to vaginal birth does not impact on the likelihood of food allergy at 12 months of age. Led by the Murdoch Children’s Research Institute (MCRI), the study was published in the Journal of Allergy and Clinical Immunology: In Practice.

Associate Professor Rachel Peters of the Children’s Research Institute (MCRI) said the association between food allergy and mode of delivery remained unclear due to the lack of studies with food challenge outcomes.

The study involved 2045 infants from the HealthNuts study, with data linked to a perinatal database for detailed information on birth factors.

The study found that, of the 30% born by caesarean, 12.7% had a food allergy compared to 13.2% born vaginally.

“We found no meaningful differences in food allergy for infants born by caesarean delivery compared to those born by vaginal delivery,” Associate Professor Peters said. “Additionally, there was no difference in the likelihood of food allergy if the caesarean was performed before or after the onset of labour, or whether it was an emergency or elective caesarean.”

Associate Professor Peters said it was thought a potential link between caesarean birth and allergy could reflect differences in early microbial exposure from the mother’s vagina during delivery.

“The infant immune system undergoes rapid development during the neonatal period,” she said. Caesarean delivery may interfere with the normal development of the immune system, as there is less exposure to the mother’s vagina and gut bacteria, influencing the baby’s own microbiome. “However, this doesn’t appear to play a major role in the development of food allergy.”

Australia has the highest rates of childhood food allergy in the world, with about one in 10 infants and one in 20 children over five years of age having a food allergy.

These findings come as other MCRI-led research found 30% of peanut allergy and 90% of egg allergy resolves naturally by age six.

Associate Professor Peters said the resolution rates were great news for families and were even a little higher than what was previously thought.

The results, published in the Journal of Allergy and Clinical Immunology, found infants with early-onset and severe eczema and multiple allergies were less likely to outgrow their egg and peanut allergies.

Associate Professor Peters said these infants should be targeted for early intervention trials that evaluate new treatments for food allergy such as oral immunotherapy.

“Prioritising research of these and future interventions for infants less likely to naturally outgrow their allergy would yield the most benefit for healthcare resources and research funding,” she said.

Source: SciTech Daily

Categories : AntibioticsTags :

Fungal Microbiota May Explain Antibiotics’ Long Term Effects in Infants

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Gut microbiome. Credit: Darryl Leja, NIH

In infants treated with antibiotics, fungal gut microbiota are more abundant and diverse compared with the control group even six weeks following the start of the antibiotic course, according to a study published in the Journal of Fungi. The study’s authors suggest that reduced competition from gut bacteria being killed by antibiotics left more space for fungi to multiply.

“The results of our research strongly indicate that bacteria in the gut regulate the fungal microbiota and keep it under control. When bacteria are disrupted by antibiotics, fungi, Candida in particular, have the chance to reproduce,” explained PhD student Rebecka Ventin-Holmberg from the University of Helsinki.

A new key finding in the study was that the changes in the fungal gut microbiota, together with the bacterial microbiota, may be partly responsible for the long-term adverse effects of antibiotics on human health.

Antibiotics are the most commonly prescribed drugs for infants, causing changes in the gut microbiota at its most important developmental stage. These changes are more long-term compared to those in adults.

“Antibiotics can have adverse effects on both the bacterial and the fungal microbiota, which can result in, for example, antibiotic-associated diarrhoea,” Ventin-Holmberg said.

“In addition, antibiotics increase the risk of developing chronic inflammatory diseases, such as inflammatory bowel disease (IBD), and they have been found also to have a link to overweight,” she added.

These long-term effects are thought to be caused, at least in part, by an imbalance in the gut microbiota.

This study involved infants with a respiratory syncytial virus (RSV) infection who had never previously received antibiotics. While some of the children were given antibiotics due to complications, others received no antibiotic therapy throughout the study.

“Investigating the effects of antibiotics is important for the development of techniques that can be used to avoid chronic inflammatory diseases and other disruptions to the gut microbiota in the future,” Ventin-Holmberg emphasised.

While there have been many studies on the effect of antibiotics on bacterial microbiota, there has been a lack of studies on fungal microbiota. This study’s findings indicate that fungal microbiota may also have a role in the long-term effects of imbalance in the gut microbiota.

“Consequently, future research should focus on all micro-organisms in the gut together to better understand their interconnections and to obtain a better overview of the microbiome as a whole,” Ventin-Holmberg noted.

Source: University of Helsinki

Categories : AntibioticsTags :

New Insights on Antibiotic-caused Diarrhoea

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Streptococcus pneumoniae. Credit: CDC

A study may have found that a effects on a key gut bacteria are the reason why some patients experience diarrhoea after receiving the widely prescribed antibiotic amoxicillin-clavulanate. 

Researchers, reporting in the journal iScience, found that the level of gut Ruminococcaceae, which plays a role in maintaining an individual’s gut health, strongly impacts diarrhoeal outcomes following antibiotic treatment.

One in three patients prescribed amoxicillin-clavulanate will develop diarrhoea. In some cases, it may be so severe that doctors have to prematurely halt the antibiotic, inadequately treating the infection or else forcing a change in antibiotics. The diarrhoea could also prolong patients’ hospital stays and further exposing them to hospital-acquired infections.

“The problem is very real for patients who are unable to take amoxicillin-clavulanate because it gives them diarrhoea, even though it is an effective and affordable antibiotic for their infection. Knowing why may help us identify those at risk of antibiotic-associated diarrhoea, and devise treatment strategies in the future to minimise or avoid such adverse effects,” said lead researcher Dr Shirin Kalimuddin.

The study recruited 30 healthy volunteers, each receiving a three-day oral course of amoxicillin-clavulanate. Their stool samples were collected over four weeks and analysed using gene sequencing to look for changes in the gut microbiome.

Ruminococcaceae levels in the stools of study volunteers who developed diarrhoea were significantly lower when compared to those who did not, both before and during treatment with amoxicillin-clavulanate. This suggests that individuals may, depending on their gut composition, be predisposed to antibiotic-associated diarrhea. The team further devised a simple polymerase chain reaction (PCR) test based on levels of Faecalibacterium prausnitzii, a species within the Ruminococcaceae family, that could potentially be used in clinical settings to quickly determine an individual’s risk of developing diarrhea with amoxicillin-clavulanate treatment.

“People respond differently to medication. Understanding this response and the ability to predict those at risk will help guide the development of point-of-care diagnostics,” said lead researcher Professor Eric J. Alm.

“While a lot of attention has been paid to how DNA influences a person’s response to medication, the impact of the gut microbiome on the human drug response has not been widely researched. Our findings provide evidence that an individual’s gut microbial composition can influence the risk of developing antibiotics-associated diarrhoea. Tested against amoxicillin-clavulanate, the study provides a framework to identify other potential causes of antibiotic-associated diarrhoea in relation to other classes of antibiotics,” added Prof Alm.

The next step would be a clinical trial to determine whether certain Ruminococcaceae could be used as a probiotic to prevent diarrhoea in patients prescribed antibiotics.

Source: EurekAlert!

Categories : Diseases, Syndromes and Conditions Immune SystemTags :

Meat, Gut Bacteria and Multiple Sclerosis

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Gut microbiome. Credit: Darryl Leja, NIH

There appears to be a link between eating meat, gut bacteria and multiple sclerosis, according to new research published in EBioMedicine. The study teased out subtle connections that could lead to a better understanding of the causes of the disease.

The autoimmune disease multiple sclerosis (MS) is more prevalent in specific regions, particularly the northern mid-latitudes, suggesting that geography is somehow linked to the disease, perhaps involving diet. However, the exact relationships between diet, immune response, and MS has been a mystery. What exactly triggers the body to attack the myelin sheaths in MS in the first place is unknown.

Growing evidence suggests that bacteria might play a role. Gut bacteria affect the immune system, and diet affects the gut. Researchers studied the gut microbiome, immune systems, diet, and blood metabolites in 25 MS patients and 24 healthy controls to look for any subtle but important correlations.

“We found a number of gut bacteria associated with MS and severity of disability of MS patients,” said Dr Yanjiao Zhou. “We also found increased autoimmune markers and signature metabolites in MS. But what is really interesting is how these systems connect with each other, and how diet is involved in these connections. Using multi-OMICS approaches, we try to close the loop and show the associations between multiple systems.”

Meat eating was the strongest link in their analysis, where higher meat consumption saw a decrease in the population of Bacteroides thetaiotaomicron, a bacteria associated with digesting carbohydrates from vegetables.

Higher meat consumption, seen in the MS patients, was also linked to an increase in T-helper 17 cells in the immune system, and an increase in S-adenosyl-L-methionine (SAM) in their blood.

Meat eating was not a predictor of MS. But the evidence suggested that, in MS, something causes gut bacteria to disassociate with the immune system, leading to heightened T-helper 17 cells and autoimmune attacks on the nervous system. And it tends to be associated with eating meat.

Future research aims to recruit more volunteers, including those with more severe MS. Eventually they hope to understand more of the cause-and-effect between diet, bacterial ecosystems in the gut, and immune response, and potentially help prevent or mitigate MS symptoms in people suffering from the disease.

Source: University of Connecticut

Categories : GastrointestinalTags :

Commonly Used Drugs Have a Significant Impact on Gut Microbiome

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Source: Pixabay CC0

Many commonly used drugs have powerful effects on the human gut microbiome, according to a large cohort study published in the journal Nature. These include drugs used to treat cardiometabolic disorders and antibiotics.

The human microbiome is composed of microbes that reside in and on our bodies, which have tremendous potential to impact our physiology, both in health and in disease. They contribute metabolic functions, protect against pathogens, educate the immune system, and, through these basic functions, affect directly or indirectly most of our physiologic functions.

“We analysed the effects of 28 different drugs and several drug combinations,” explained Professor Peer Bork, Director of Scientific Activities at EMBL Heidelberg, “Many drugs negatively impact the composition and state of the gut bacteria, but others, including aspirin, can have a positive influence on the gut microbiome. We found that drugs can have a more pronounced effect on the host microbiome than disease, diet, and smoking combined.”

While the negative and lasting impact of antibiotics on gut bacteria is already well-known, this study showed that such effects likely accumulate over time. “We found that the gut microbiome of patients taking multiple courses of antibiotics over five years became less healthy. That included signs indicating antimicrobial resistance,” said co-first author of the study Dr Sofia Forslund.

“We wanted to disentangle the effect that diseases have on host microbiomes from the effect of medications, particularly in patients taking more than one drug at the same time,” said co-first author Dr Maria Zimmermann-Kogadeeva. “Being part of the MetaCardis consortium enabled us to use multi-omics data from more than 2000 patients with cardiometabolic diseases,” she added. The cohort’s large size also let the researchers establish that drug dosage also has a significant effect on the level of impact on the microbiome.

“We know that the microbiome can reflect the status of a patient’s health and provide a range of biomarkers to assess the severity of diseases. What is often overlooked, however, is that the medication used to treat a disease also affects the state of the microbiome,” added Dr Rima Chakaroun, one of the lead authors.

The researchers came up with a statistical approach to tease out the effects of drugs and disease separately. “We now have a robust methodological framework that makes it possible to get rid of many of the standard errors,” said Professor Bork. “That allowed us to show that medication can mask the signatures of disease and conceal potential biomarkers or therapeutic targets.”

It is hoped that these results could potentially inform drug repurposing as well as in planning individualised treatment and prevention strategies.

The study combined the insight, knowledge and approaches of experts in six countries. “It was very motivating to work with an interdisciplinary team of clinicians, bioinformaticians, and computational systems biologists to advance our understanding of molecular interactions in cardiometabolic disease,” said Dr Zimmermann-Kogadeeva.

Source: European Molecular Biology Lab

Categories : GastrointestinalTags :

IBS Dietary Therapy Works Best with Certain Gut Microbiomes

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Beneficial gut bacteria. Credit: Darryl Leja, National Human Genome Research Institute, National Institutes of Health

People who respond well to the irritable bowel syndrome (IBS) dietary therapy of reduced fermentable carbs have an abundance of particular types of bacteria in their gut, reveals research published online in the journal Gut.

The composition of the gut microbiome is thought to have a major role in the development of IBS. Restricting fermentable carbs, found in many foods including wheat, onions, and milk, is usually recommended to ease symptoms, an approach known as the low FODMAP (fermentable oligo-, di-, mono-saccharides and polyols) diet. But why this diet works is not fully understood.

In a bid to fill this knowledge gap, the researchers analysed stool samples of 56 people with IBS and 56 people who lived with them, but without the condition, to identify the microbial profile and genes involved in converting food into active molecules while on their usual diet.

They then assessed the clinical response in 41 of these pairs after 4 weeks on the low FODMAP diet by reviewing their stool samples again.

Before adoption of the low FODMAP diet, analysis of the stool samples of those with IBS revealed two distinct microbial ‘signatures’, which the researchers referred to as ‘pathogenic-like’ (IBSP) and as ‘health-like’ (IBSH).

The pathogenic microbial signature was abundant in harmful Firmicutes sp, including known disease causing bacteria, such as C. difficile, C. sordellii and C. perfringens, but very low in beneficial Bacteroidetes species.

The lactic acid bacteria Streptococcus parasanguinis and Streptococcus timonensis that are usually found in the mouth were also abundant. And bacterial genes for amino acid and carbohydrate metabolism were overexpressed, which may explain the excess of some metabolites that are linked to IBS symptoms, say the researchers.

The healthy microbial signature of the other IBS patients was similar to that found in the comparison group (household members).

After 4 weeks on the low FODMAP diet, the microbiome of the comparison group and those with the healthy microbial profile stayed the same.

But the microbiome of those with the pathogenic profile became healthier, with an increase in Bacteroidetes, and a fall in Firmicutes species. And the bacterial genes involved in the metabolism of amino acids and carbs were no longer overexpressed.

In 3 out of 4 of IBS patients, symptoms improved. But the clinical response to the low FODMAP diet was greater in those with IBS and a pathogenic microbial signature than it was in those with IBS and a healthy microbial signature in their gut.

“The evidence associating diet, the microbiome and symptoms in [pathogenic IBS] is compelling, but studies following the introduction of candidate organisms into an animal model are needed to prove the relationship is causal,”  the researchers cautioned.

Nevertheless, they suggest their findings could lead to a microbial signature to identify those who would respond best to a low FODMAP diet and better manage those who wouldn’t.

“If the bacteria represented in the [pathogenic] subtype are shown to play a pathogenic role in IBS, perhaps through their metabolic activity, this provides a target for new therapies and an intermediate [marker] by which to assess them,” they suggest.

In a linked editorial, Professor Peter Gibson and Dr Emma Halmos of Melbourne’s Monash University, describe the introduction and adoption of the FODMAP diet as “a major change in the management of patients with irritable bowel syndrome (IBS) towards integrated care.

But while “an effective symptomatic therapy, [it’s] one that carries risks associated with exacerbating disordered eating, challenging nutritional adequacy and putatively inducing dysbiotic gut microbiota,” they added.

They point out some limitations of the research, including that FODMAP intake was poorly assessed, fibre intake,which can also influence the microbiome wasn’t reported and patient drop-out reduced the power of the study.

Nevertheless, the authors concluded that “the beauty of [the study] is not in its definitive nature, but that it enables the creation of feasible innovative hypotheses that can be examined by focused studies. Perhaps the FODMAP diet is not just a symptomatic therapy.” 

Source: BMJ