Crohn's caused by showers and rivers?

New research from Lancaster University has found the MAP pathogen associated with Crohn's Disease to be present in 10% of domestic showers sampled and in the spray from a Welsh river. It is suggested that these may be mechanisms by which people can be infected, and that this may be a trigger for Crohn's.

It has long been suspected that the consumption of milk may be the route for MAP to enter the human body, but this appears to be the first research into infection through inhalation. However, it should be noted that it has yet to be proven that MAP is the cause of Crohn's. Even if MAP is present in most people in Crohn's it does not necessarily mean that it was the cause rather than a result of the condition.

Full details of this research can be read for free in the open access journal Pathogens.

Worms trial terminated

A disappointing report from Medpage Today indicates that a German trial of whipworm for the control of Crohn's Disease has been cancelled due to poor results. Whilst there were no safety concerns from the trial the hoped for response to the treatment had not occurred.

Although there is plenty of anecdotal evidence of the effectiveness of helminths, to date I know of no full-scale clinical trials which have proven successful. I hope the failure of this trial will prompt researchers to investigate further and propose further avenues of to explore in this promising area.

Crohn's vaccine

Mycobacterium avium subspecies paratuberculosis (MAP) has been a contender as a cause of Crohn's for a while, but nothing conclusive has been determined. It causes the Crohn's-like Johne’s disease in cattle, and people with Crohn's are significantly more likely to have MAP in their intestines than non-sufferers. The theory is that susceptible people who drink MAP-contaminated milk will may develop Crohn's. Pasteurisation of milk does not eliminate MAP, but ultra-heat treatment, as used in long-life milks, does.

The Western Farm Press has an interview with veterinary professor William Davis which outlines why he believes the MAP link to Crohn's should be investigated further.

"We know the incidence of Johne’s is on the rise, as is the incidence of Crohn’s,” said Davis, whose research has included collaboration with physicians and immunologists. "The problem is too important and the theory is sufficiently plausible that we need to be taking a closer look. More research is necessary to resolve exactly what the link is.”

He also notes that preliminary work has found that his vaccine against MAP in cattle has seemed effective. If it is successful then this may eliminate MAP entering the human food chain, and possibly reducing the incidence of Crohn's.

Note, however, that antibiotics to combat MAP have thus far been ineffective against Crohn's, and the MAP link is far from proven.

Vitamin D may reduce risk of developing Crohn's

Two years after two previous reports on the role vitamin D may play in the development of Crohn's Disease, Medscape has noted the results of a new study. It found that women deficient in vitamin D were far more likely to develop Crohn's. The researchers went on to suggest that this would make vitamin D supplements a potential area of interest in the treatment of active Crohn's or the maintenance of remission.

New Scientist calls for worm investigation

An editorial in the latest New Scientist, Let them eat worms, calls for a relaxation of regulations so that full-scale clinical trials into the use of parasitic worms called helminths can be undertaken. A story in issue 2824, Citizen scientists eat worms to treat disorders (subscription required) [titled "One sugar or two with your parasites?" in the print edition], further explains why helminthic therapy is so promising.

Small trials run in the past ten years, including those by Joel Weinstock of Tufts University, and John Crease of Townsville Hospital, have shown promising results. The expansion to larger trials has not occurred because of the safety issues involved in infecting large groups of volunteers with living organisms, with the potential for severe illness to result. Some researchers feel that the mechanism by which helminths subdue the immune system should be determined and replicated with medication, rather than introducing worms into the patients.

The usage of worms to treat Crohn's disease has been a promising avenue of investigation for a number of years now, but not much progress has been made. Anecdotally, worms seem to be more successful and produce fewer side-effects than many of the current medicines. However, people should not have to experiment on themselves to find if worm therapy is their best course of action. Full-scale clinical trials are needed, and proper scientific analysis to work out if it should be added to the mainstream options available for the treatment of Crohn's.

Infliximab effective after surgery

Research published in Clinical Gastroenterology and Hepatology shows the continuation of infliximab after surgery is effective and useful, even at a low dose.

Patients were given infliximab for three years after surgery, and those with no symptoms then ceased the medication. 83% of those then showed clinical symptoms after a few months, and they were put back onto a low dose of infliximab. This controlled the disease in all patients.

Whilst it's disappointing that most patients were unable to remain in remission without medication, the success of a lower than standard dosage is good news.

Vitamin D to combat Crohn's

Two new studies have pointed to Vitamin D having a role in fighting Crohn's. Scientists believe that the boost to the immune system provided by Vitamin D could benefit Crohn's sufferers, and perhaps ensuring adequate Vitamin D levels could prevent Crohn's from occurring.

As noted in Science Daily:

Dr. White and his team found that Vitamin D acts directly on the beta defensin 2 gene, which encodes an antimicrobial peptide, and the NOD2 gene that alerts cells to the presence of invading microbes. Both Beta-defensin and NOD2 have been linked to Crohn's disease. If NOD2 is deficient or defective, it cannot combat invaders in the intestinal tract.

The Telegraph states:

“Scientists have known for a long time that vitamin D is important for calcium absorption and the vitamin has also been implicated in diseases such as cancer and multiple sclerosis, but what we didn’t realise is how crucial vitamin D is for actually activating the immune system – which we know now, ” said the researchers.

It's interesting that these different mechanisms for Vitamin D to enhance the immune systems have been reported on almost simultaneously. Although their link to Crohn's is speculative, it opens further avenues for research. Who wouldn't hope for a cod liver oil tablet cure?

Genes causing defective gut lining

The BBC reports that research comparing the genes of thousands of people with or without ulcerative colitis has found four genes of interest. They affect the lining of the intestine, and in those with ulcerative colitis the lining may be letting excessive bacteria through.

Researcher Dr Miles Parkes, Consultant Gastroenterologist at Addenbrooke's Hospital, Cambridge, said: "We have long suspected that genetic defects in the epithelial barrier are important in ulcerative colitis.

"This large scale genetic study provides the first robust genetic evidence that this is the case."

More detailed information about this research is available from the Wellcome Trust.

With the ever increasing knowledge of genetic factors influencing inflammatory bowel disorders it's only a matter of time before more effective and better targeted treatments can be found.

Ineffective interleukin-10?

The Atlanta Journal-Constitution reports that a small study of children with severe colitis has found a genetic mutation that reduced the effectiveness of interleukin-10 in their immune systems. Researchers are now considering whether a subset of adult Crohn's cases have a similar cause. If so, then a more direct treatment could be found.

One child in the study was completely cured by a bone marrow transplant. Although such transplants have been used for severe Crohn's cases, they are highly risky. This research should assist in determining the efficacy of such a treatment.

Interleukins have been implicated in Crohn's in the past, but this is the first study to target IL-10 in particular. It has been suggested that Crohn's is a blanket term for a variety of IBD conditions of various causes, and this research is another indication that this may be true.

Weak immune response blamed

In the long-running debate over whether Crohn's is caused by over-active or under-active immune systems the New Scientist reports on research that tips it in favour of the under-active hypothesis.

Segal and his colleagues got their first clue when they noticed a weaker immune response in people with Crohn's than in healthy people after both groups were injected with heat-killed Escherichia coli. The team reasoned that this lukewarm response might allow an infection to build up and eventually trigger a debilitating secondary immune response, resulting in Crohn's.

...

The team concluded that ineffectual rallying of immune cells in people with defective macrophages is what allows intestinal bacteria to run amok in the early stages of an infection, setting in motion the series of events that leads to Crohn's disease.

The full research published in the The Journal of Experimental Medicine contains the juicy details in addition to good background information on the current status of Crohn's research. Although they don't specifically mention new treatments resulting from this discovery, it seems likely to open new avenues for scientists to explore.