E. Coli Linked to Inflammatory Bowel

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Thought this may be interesting to some... It was

posted here with permision from anouther group I am

on.

 

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E. Coli Linked to Inflammatory Bowel

Disease

Tue Feb 5,12:00 PM ET

 

By Nicolle Charbonneau

HealthScoutNews Reporter

 

TUESDAY, Feb. 5 (HealthScoutNews) -- An intestinal

infection caused

by

strains of a common

bacterium may be linked to the development of

inflammatory bowel

disease, a new study says.

 

French researchers report that a heightened immune

interaction

between

Escherichia coli and the

cells lining the intestine may result in the

symptoms experienced by

people with inflammatory bowel

disease (IBD). They suggest their work indicates

antibiotics might be a

useful tool when treating IBD.

 

The findings appear in today's issue of the

Proceedings of the National

Academy of Sciences.

 

IBD refers to a group of conditions that cause

inflammation of the

intestinal tract. The group includes

Crohn's disease, irritable bowel syndrome and

ulcerative colitis.

 

Symptoms of these disorders include changes in bowel

habits,

particularly diarrhea, as well as

abdominal pain, fever, joint pain and skin lesions.

 

IBD affects approximately 2 million Americans, with

symptoms

generally

appearing in a person's 20s

or 30s. There is evidence that a predisposition to

these conditions can

be

inherited, with the diseases

being particularly common in people of eastern

European and Jewish

descent.

 

A research team led by Dr. Antoine Toubert suggests

that in

genetically

susceptible people, the immune

system's response to bacteria could trigger the

inflammation

associated

with these diseases.

 

Toubert, an associate professor of immunology and

histocompatibility

at

the Hôpital Saint-Louis in

Paris, studied this response in two

laboratory-cultured strains of human

cells.

 

The researchers found that when certain strains of

E. coli bind to a

molecule called CD55 on the

surface of cells lining the interior of the

intestine using a protein

called

afaE, it causes a sudden increase

in production of an immune molecule called MICA.

 

The boosted MICA levels prompt " natural killer " (NK)

immune cells to

release gamma interferon. This

protein triggers the production of immune cells

called macrophages,

which

the researchers suspect

could be linked to the chronic inflammation

associated with this

digestive

disorder.

 

" We believe that it could be one of the parameters ?

which could

increase and perpetuate the local

inflammation in the bowel, " says Toubert.

 

His team also examined samples of colon tissue

surgically removed

from 18

patients with Crohn's

disease and compared them to normal colon tissue

removed during

colon

cancer surgery. They found

increased MICA production in the cells taken from

patients with Crohn's

disease, compared to the

normal colon tissue samples.

 

He suspects other bacteria may have the same effect.

" We have seen

this effect with [diffusely

adherent] E. coli, but it may be the case for other

strains which we

have

 

not tested, " he says.

 

Dr. R. Balfour Sartor, a professor of medicine,

microbiology and

immunology at the University of

North Carolina at Chapel Hill, studies the

relationship between bacteria

and inflammatory bowel

disease.

 

" They're establishing a possible mechanism by which

a bacteria that

adheres to the surface of an

[intestinal lining] cell could then activate a

response in NK cells, " as

well

as certain classes of cells that

mediate immunity, says Sartor.

 

He says the findings, while consistent with animal

studies of a bacterial

 

agent stimulating inflammation

that could potentially lead to IBD, don't show that

this type of

inflammation

occurs only in IBD.

 

However, he notes that studies have shown that a

high percentage of IBD

patients showing early

reactivation of disease after surgery have a form of

E.coli in their

system.

 

Toubert stresses these findings are preliminary, but

says it may

indicate

 

that antibiotic treatments in

some patients with IBD would be beneficial.

 

According to Sartor, " it's clear that antibiotics do

have a role in

treating

Crohn's patients, particularly

those that have colonic involvement. " The

antibiotics Flagyl

(metronidazole) and Cipro (ciprofloxacin)

are most commonly used, he says, but he notes Flagyl

doesn't affect

E.

coli, suggesting other bacterial

agents are at work.

 

Toubert now plans to carry out more detailed studies

of immune cells

from

 

inflammatory lesions in the

intestinal lining of IBD patients.

 

What To Do

 

The National Institute of Diabetes & Digestive &

Kidney Diseases

provides this information on

Crohn's disease, irritable bowel syndrome and

ulcerative colitis.

 

You can also check out this information from the

Crohn's & Colitis

Foundation of America.

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