Bad gut bacteria named as Crohn's culprit

Hopeful news

Researchers believe they have uncovered the identity of the bacteria involved in the inflammatory bowel disease known as Crohn's.

The findings could help predict how severe the disease will be and lead to more targeted treatments, say Dr Ramnik Xavier of Harvard University, who is senior author of a new study published today in Cell Host and Microbe.

"What we have is a microbial atlas of Crohn's Disease - obviously the next step is to find out how these bacteria cause inflammation," says Xavier.

In Crohn's Disease the walls of the intestine become inflamed, which can lead to cramping pain in the abdomen, diarrhoea and bleeding from the rectum, among other symptoms.

Both genetic and environmental factors are believed to lead to Crohn's, says Xavier.

He says the current hypothesis is that people with certain gene variants can develop an abnormal immune response to gut bacteria, when there is a change in the profile of their gut bacteria - their 'microbiome'.

To investigate the microbiome involved in Crohn's Disease, Xavier and colleagues from 28 gastroenterology centres across North America, investigated gut bacteria in 447 children who had just recently acquired the disease and had yet to be treated.

Tissue biopsies

In the largest study of its kind, the researchers compared biopsies taken from different locations of the gastrointestinal tract of the children with Crohn's and compared these with samples taken from 221 non-affected children. They collected samples from inflamed and non-inflamed sites of the gut, and from patients' stools.

"We then also validated the findings that we identified in this cohort in an independent children and adult population of about 800 patients," says Xavier.

They found in patients with Crohn's disease, there was an increase in pathological bacteria (such as Enterobacteriaceae, Pasteurellaceae, Veillonellaceae, and Fusobacteriaceae), and a decrease in less beneficial ones (such as Erysipelotrichales, Bacteroidales, and Clostridiales).

"There is an increase in the so-called inflammation-associated bacteria and there is a decrease in bacteria that are good for health," says Xavier.

Interestingly, the researchers found that giving antibiotics actually increased pathological microbes while killing off beneficial ones.

"This suggests the use of antibiotics in early-onset Crohn's Disease probably needs to be revisited," says Xavier.

Currently the conventional treatment for Crohn's is immunosuppressive drugs.

Xavier says the findings may provide a "blueprint to develop microbial therapeutics" in which, for example, drugs are developed to target specific metabolites from the pathological microbes.

The study also found the more pathological bacteria present, the more inflammation there was, suggesting the ratio between the two types of bacteria could be used to help predict the severity of the disease, says Xavier.

Important findings

Australian gastroenterologist, Professor Warwick Selby, from the Royal Prince Alfred Hospital and the University of Sydney says the new study addresses the limitations of previous research.

Most previous studies have looked at bacterial profiles in stools but Xavier and colleagues show the need to look at bacteria in tissue biopsies from the site of the disease, says Selby.

"The fact they had consistent changes found on tissue samples is very important," he says.

Also previous studies have tended to be in people who have already commenced treatment, which itself may affect the microbiome, adds Selby.

But, he says, it's still unclear whether the changed microbiome found by Xavier and team was there before the people developed Crohn's or came as a result of inflammation.

"Is it the chicken or the egg?" says Selby. "Are these bacteria driving the inflammation or are they there because the tissue is inflamed and that's the environment that they like to live in?"

He says answering this would require a study of tissue samples from family members who don't have Crohn's disease to see if they have these changes as well. Other future studies should also look at whether treatment alters the microbiome.

Selby agrees that if the bacteria identified are indeed causing inflammation, the findings could help the development of more targeted treatments for Crohn's Disease.

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Could getting married save your life? Women are far less likely to die from heart disease if they have a partner, researchers claim

Or is it that healthier people are more likely to get married?

Married women are 28% less likely to die from heart disease than unmarried women - and it's all down to nagging.

Researchers say that even though marriage makes no difference to women's chances of developing heart disease, they are more likely to get treatment early is a partner constantly encourages them to.

They also believe that getting married can lead to lifestyle changes, and mean women are more likely to take medication.

The findings come from the latest analysis of data from a large UK study of women's health run by Oxford University researchers, the Million Women Study.

This new study, published in the journal BMC Medicine, included 730,000 women who were on average 60 years old.

Over a nine-year period, 30,000 of these women developed heart disease and 2,000 died from the condition.

The scientists behind the study admit they do now know the reasons for this difference.

However, Dr Sarah Floud and colleagues at Oxford University's Cancer Epidemiology Unit suggest one explanation could be that the partners of married women may encourage them to seek early medical treatment for symptoms.

'Married women were no less likely to develop heart disease than women who were not married, but they were less likely to die from it,' Dr Floud said.

'This means that, over 30 years, about three in 100 married women would die from heart disease compared with about four in 100 women who are not married or living with a partner.'

Other studies have also shown that partners tend to encourage their spouses to take medication and make changes in unhealthy lifestyles.

The findings come from the latest analysis of data from a large UK study of women's health run by Oxford University researchers, the Million Women Study.

This new study, published in the journal BMC Medicine, included 730,000 women who were on average 60 years old.

Over a nine-year period, 30,000 of these women developed heart disease and 2,000 died from the condition.

The researchers found that married women, or those living with a partner, had the same risk of developing heart disease as unmarried women (this included single, widowed and divorced women).

But the chance of dying from heart disease was 28% lower.

The study took many factors into account that could have influenced the results, such as age, socio-economic status and lifestyle, but the lower risk of death from heart disease remained.

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