The Latest Research on the Human Microbiome

salmonellaHave you kept up-to-date with the latest research on the human microbiome? If not, here’s your chance to catch up. As always, I’ve picked out a selection of scientific papers and articles that I found interesting and think the readers of www.Darwinian-Medicine.com will enjoy. Leave a comment in the comment section if you have any opinions or questions related to the information in today’s post or if you’ve come across interesting new research that you think deserves to be mentioned. 

The microbiome in health and disease

Connections between gut microbiota and the brain

Intestinal bacteria that can boost bravery or trigger multiple sclerosis: An increasing body of research results confirms the importance of the “gut-brain axis” for neurology and indicates that the triggers for a number of neurological diseases may be located in the digestive tract. Read more…

Bugging inflammation: role of the gut microbiota

The advent of vaccination and improved hygiene have eliminated many of the deadly infectious pathogens in developed nations. However, the incidences of inflammatory diseases, such as inflammatory bowel disease, asthma, obesity and diabetes are increasing dramatically. Research in the recent decades revealed that it is indeed the lack of early childhood microbial exposure, increase use of antibiotics, as well as increase consumption of processed foods high in carbohydrates and fats, and lacking fibre, which wreak havoc on the proper development of immunity and predispose the host to elevated inflammatory conditions. Although largely unexplored and under-appreciated until recent years, these factors impact significantly on the composition of the gut microbiota (a collection of microorganisms that live within the host mucosal tissue) and inadvertently play intricate and pivotal roles in modulating an appropriate host immune response. The suggestion that shifts in the composition of host microbiota is a risk factor for inflammatory disease raises an exciting opportunity whereby the microbiota may also present as a potential modifiable component or therapeutic target for inflammatory diseases. Read more…

Posttraumatic Stress Disorder: Does the Gut Microbiome Hold the Key?

Recent experimental and clinical data converge on the hypothesis that imbalanced gut microbiota in early life may have long-lasting immune and other physiologic effects that make individuals more susceptible to develop PTSD after a traumatic event and contribute to the disorder. This suggests that it may be possible to target abnormalities in these systems by manipulation of certain gut bacterial communities directly through supplementation or indirectly by dietary and other novel approaches. Read more…

Fecal Microbiota Transplants Sends Ulcerative Colitis Patients to Remission

Patients with active UC [Ulcerative Colitis] who were resistant to standard treatments received a single FMT or placebo colonoscopy infusion on day one, followed by either FMT or placebo enemas five times per week for eight weeks. Each enema was developed from three to seven unrelated donors. The researchers measured the patients’ rectal bleeding, stool frequency and endoscopic appearance after the full eight weeks, in addition to their clinical response, quality of life and safety.

The researchers reported that steroid free clinical remission and endoscopic remission or response was reached in 11 of 41 FMT patients (27 percent) compared to just three of 40 placebo patients (8%). The rate of steroid free clinical remission was 44% vs. 20%, respectively, while the rate of clinical response was 54% vs. 23%, respectively. Read more…

Genetic variants in patients with crohn’s disease prevent ‘good’ gut bacteria from working

A major type of inflammatory bowel disease (IBD) may be caused in part by genetic variants that prevent beneficial bacteria in the gut from doing their job, according to a new study published today in the journal Science. Read more…

From IBS to DBS: The Dysbiotic Bowel Syndrome.

Irritable bowel syndrome is a chronic gastrointestinal disorder characterized by abdominal pain and altered bowel habits in the absence of organic disease. We present 2 cases where diarrhea-predominant irritable bowel syndrome occurred in association with earlier intestinal infection or antibiotic treatment. Both were successfully treated with instillation of an anaerobic cultivated human intestinal microbiota. Thereafter, they were symptom free for at least 12 months. We now introduce the term dysbiotic bowel syndrome covering cases where a disturbed intestinal microbiota is assumed to be present. We recommend that restoration of the dysbiotic gut microbiota should be first-line treatment in these conditions. Read more…

The impact of diet and lifestyle on the gut microbiota

Dietary fiber intake tied to successful aging, research reveals

Using data compiled from the Blue Mountains Eye Study, a benchmark population-based study that examined a cohort of more than 1,600 adults aged 50 years and older for long-term sensory loss risk factors and systemic diseases, the researchers explored the relationship between carbohydrate nutrition and healthy aging.

They found that out of all the factors they examined — which included a person’s total carbohydrate intake, total fiber intake, glycemic index, glycemic load, and sugar intake — it was the fiber that made the biggest difference to what the researchers termed “successful aging.”

Successful aging was defined as including an absence of disability, depressive symptoms, cognitive impairment, respiratory symptoms, and chronic diseases including cancer, coronary artery disease, and stroke. Read more…

Why Processed Foods May Promote Gut Inflammation

In the study, researchers looked at ingredients called emulsifiers, which are added to many processed foods, including ice cream and peanut butter, to improve those foods’ texture and extend their shelf life. The researchers used a special piece of lab equipment that’s intended to simulate the human gut, including its bacteria, and consists of a series of pumps and glass containers. The scientists added two emulsifiers called carboxymethylcellulose (CMC) and polysorbate-80 (P80), to a simulation of normal gut contents. Adding the emulsifiers led to a dramatic increase in a marker of gut inflammation, said study co-author Benoit Chassaing… Read more…

Gut bust
Intesinal microbes in peril

The Sonnenburgs are concerned that our modern ways — and most particularly our diet — have caused the diversity of our intestinal biota to shrink substantially. Worse, new experiments they’ve conducted suggest that this shrinkage may be handed down over the generations. Read more…

Western diet induces a shift in microbiota composition enhancing susceptibility to Adherent-Invasive E. coli infection and intestinal inflammation.

Recent advances have shown that the abnormal inflammatory response observed in CD [Crohn’s disease] involves an interplay among intestinal microbiota, host genetics and environmental factors. The escalating consumption of fat and sugar in Western countries parallels an increased incidence of CD during the latter 20th century. The impact of a HF/HS diet in mice was evaluated for the gut micro-inflammation, intestinal microbiota composition, function and selection of an E. coli population. The HF/HS diet created a specific inflammatory environment in the gut, correlated with intestinal mucosa dysbiosis characterized by an overgrowth of pro-inflammatory Proteobacteria such as E. coli, a decrease in protective bacteria, and a significantly decreased of SCFA concentrations. Read more…

The influence of a short-term gluten-free diet on the human gut microbiome

Conclusions: We have identified eight taxa and 21 bacterial pathways associated with a change from a habitual diet to a GFD [Gluten-Free Diet] in healthy individuals. We conclude that the effect of gluten intake on the microbiota is less pronounced than that seen for a shift from a meat-based diet to a vegetarian diet (or vice versa). However, a GFD diet clearly influences the abundance of several species, in particular those involved specifically in carbohydrate and starch metabolism. Our study illustrates that variations in diet could confound the results of microbiome analysis in relation to disease phenotypes, so dietary variations should be carefully considered and reported in such studies. The short-term GFD did not influence the levels of inflammatory gut biomarkers in healthy individuals. Further research is needed to assess the impact of a GFD on inflammatory and metabolic changes in gut function in individuals with gastrointestinal conditions such as IBS and gluten-related disorders. Read more…

Breast milk hormones found to impact bacterial development in infants’ guts
Intestinal microbiome of children born to obese mothers significantly different from those born to mothers of healthy weight

“This is the first study of its kind to suggest that hormones in human milk may play an important role in shaping a healthy infant microbiome,” said Bridget Young, co-first author and assistant professor of pediatric nutrition at CU Anschutz. “We’ve known for a long time that breast milk contributes to infant intestinal maturation and healthy growth. This study suggests that hormones in milk may be partly responsible for this positive impact through interactions with the infant’s developing microbiome.”

Researchers found that levels of insulin and leptin in the breast milk were positively associated with greater microbial diversity and families of bacteria in the infants’ stool. Insulin and leptin were associated with bacterial functions that help the intestine develop as a barrier against harmful toxins, which help prevent intestinal inflammation. By promoting a stronger intestinal barrier early in life, these hormones also may protect children from chronic low-grade inflammation, which can lead to a host of additional digestive problems and diseases. Read more…

Fermented Milk Containing Lactobacillus casei Strain Shirota Preserves the Diversity of the Gut Microbiota and Relieves Abdominal Dysfunction in Healthy Medical Students Exposed to Academic Stress.

Stress-induced abdominal dysfunction is an attractive target for probiotics. To investigate the effects of the probiotic Lactobacillus casei strain Shirota on abdominal dysfunction, a double-blind, placebo-controlled trial was conducted with healthy medical students undertaking an authorized nationwide examination for academic advancement. Read more…

Antibiotics that kill gut bacteria also stop growth of new brain cells

Antibiotics strong enough to kill off gut bacteria can also stop the growth of new brain cells in the hippocampus, a section of the brain associated with memory, reports a new study in mice. Researchers also uncovered a clue to why — a type of white blood cell seems to act as a communicator between the brain, the immune system, and the gut. Read more…

Other topics

Do microbiotas warm their hosts?

All natural animals and plants are holobionts, consisting of a host and abundant and diverse microbiota. During the last 20 years, numerous studies have shown that microbiotas participate in the ability of their hosts to survive and reproduce in a particular environment in many ways, including contributing to their morphology, development, behavior, physiology, resistance to disease and to their evolution. Here we posit another possible contribution of microbiotas to their hosts, which has been underexplored – the generation of heat. We estimate that microbial metabolism in the human gut, for example, produces 61 kcal/h, which corresponds to approximately 70% of the total heat production of an average person at rest. Read more…

Federal Microbiome Project Aims to Solve Tiny Riddles of Science

The Obama administration on Friday will announce the latest in its scientific “moonshots,” this one in the red-hot field of microbiomes — the trillions of micro-organisms in places like soil and the human gut.

The new National Microbiome Initiative is intended to create scientific tools, discoveries and training techniques that could advance efforts to cure asthma and depression, clean up oil spills and even increase crop yields. The initiative will involve more than a dozen federal agencies, top universities, major philanthropies and corporate giants. Read more…

Twin study finds that gut microbiomes run in families

A genome-wide association analysis of over 1,000 twins in the UK supports that some parts of our microbiomes are inherited and shaped — not through a spread of microbes from parent to child, but through our genes. The results, reveal new examples of heritable bacterial species including those related to diet preference, metabolism, and immune defense. Read more…

Most Gut Microbes Can Be Cultured

Overall, the team isolated 137 distinct species, 90 of which were on the Human Microbiome Project’s “most wanted” list of previously uncultured and unsequenced microbes. Collectively, the bacterial colonies the researchers isolated and preserved represent 90 percent of the bacterial population identified across the six study participants. “Before this, the common dogma has been that you can only culture 1 [percent] to 5 percent of the microbiota,” said Lawley. “But what we claim is that you can actually culture the vast majority of it.” Read more…

Your Invisible Neighbors: Each City Has Unique Microbes

If you’re like most people in North America, you probably spend most of your time indoors. Leave home in the morning, drive to work, stay in your cube all day, head home again. Ninety percent of our lives are spent inside a built environment of some kind – ones that we share with millions of invisible microbes.

Scientists increasingly recognize that rooms and buildings have their own microbiomes, and that those microbial roommates may affect the health of human inhabitants. Those microbes vary depending on what city you’re in, according to a study published Tuesday. Read more…

Comments

  1. i like this article…. so amazing

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