Can eating bad chicken cause arthritis?

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Arthritis, Bacteria, and Devious Cells

Rush, Medical Writer

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Can eating bad chicken cause arthritis? Researchers say that invasions

of bacteria in the body, like Salmonella, the kind seen in food

poisoning, can cause people to develop an autoimmune condition called

reactive arthritis. In the February 2000 issue of the journal Nature

Medicine, researchers at s Hopkins University Medical School

reported an important link between some bacterial infections and the

development of arthritis.

" Some of our colleagues at the Uniformed Services University of the

Health Sciences in Bethesda were interested in Salmonella disease, "

reports Mark Soloski, PhD, one of the principal investigators. " And

since we do basic research in the immune system, we decided to join

together to look at possible links between specific bacterial infections

and autoimmune diseases such as arthritis. Very little is known about

how the immune system responds to Salmonella, " Soloski continues, " but

we do know how badly it can affect people. "

If you've ever had Salmonella infection, you know what he means.

Symptoms include fever, abdominal cramps, vomiting, and diarrhea, and

can last 4-7 days, according to the Centers for Disease Control and

Prevention. Common sources of the infection are undercooked eggs,

chicken, and pork.

Soloski's team focused on Salmonella because it is believed to trigger

arthritis in some people. " As many as 10% of those who get Salmonella

poisoning develop a reactive kind of arthritis which lasts a few weeks, "

Soloski says, " but a smaller, significant number of those patients get a

severe, debilitating type of arthritis that's long-lasting. "

Healthy Cells Under Attack

Soloski's research was conducted on laboratory mice because of the

similarity between their immune system and that of humans. In autoimmune

diseases, protective cells are attacked, causing an immune system

breakdown. When the immune system is weakened, so is the body's

protection against illness.

Mice were injected with Salmonella bacteria, and the behavior of their

immune cells was observed. The results were baffling. The scientists

studied the behavior of typical bacteria-fighting immune cells that

normally make it very clear when they are being invaded. " They display

small pieces of bacterial proteins on their surface that say, in effect,

'Hey, here's a sick cell,' " Soloski says. These signals are called

" flags, " and are almost identical to what scientists call a " universal

housekeeping molecule, " which help proteins keep their shape. When the

researchers artificially coaxed the mouse cells to display the

Salmonella " flag, " the bacteria-fighting cells went into action. But

they also charged into battle when this " housekeeping flag " was

displayed, attacking a " good cell " that merely resembled the bacteria

cells.

According to Soloski, the same thing happens in humans. Their next step

is to crack this case of " mistaken identity. " It was reported in the

June 1999 issue of Nature Medicine that a group of scientists from the

University of Goteborg, Sweden, injected E. coli bacteria into the knee

joints of mice. In 2 hours, those mice developed arthritis that lasted

for at least 14 days. Soloski's team also conducted a smaller study in

which they found that normal, uninfected body cells could be attacked by

bacteria-fighting cells if the normal cells were somehow stressed --

exposed to higher temperatures, radiation, or general infection. Though

Soloski reports that they do not know what causes this attack, the

researchers feel it is a good place to study other triggers of

autoimmune disease.

So what does this mean for you? Soloski will only say that " the numbers

are still small. However, if a large group gets exposed to the

Salmonella bacteria at once, the chance for an arthritic response is

great. If something like Salmonella breaks out in a large venue like

hotel dinners, cruise ships, and the like, " he says, " you'll likely see

more incidence of reactive arthritis. "

Body Systems

According to the National Institutes of Health, scientists, in addition

to studying immune systems, are also looking at the complex

relationships between the hormonal and nervous systems in the

development of arthritis. For example, it appears that changes in the

levels of steroid hormones (such as estrogen and testosterone) during a

person's lifetime can affect the disease. Women, for example, are

statistically more likely to develop rheumatoid arthritis than men, and

this may be because of the difference in hormone levels. Rheumatoid

arthritis, some studies show, may improve during pregnancy. Whether this

is due to hormones or differences in certain proteins between a mother

and the fetus is not yet known.

Keep Moving

You don't need to be reminded again that exercise is good for you. Or

maybe you do. Arthritis and lower back pain are often linked in

discussion because what helps one can often help the other. At the 1999

National Scientific Meetings of the American College of Rheumatology, a

study by Brazilian researchers confirmed that walking helps pain

sufferers: Forty-nine patients suffering from lower back pain completed

the study, which compared patients who walked in addition to taking

medication with those who just took medication. Of those who walked for

30 minutes most days (including those who took three 10-minute walks),

92% reported significant reductions in pain, compared to only 40% who

only took medication. Moderate intensity exercise (like walking)

improves fitness and flexibility, reduces pain, and results in less

reliance on medication.

Apr.2000 © 2000 by Medscape Inc. All rights reserved. Rush is a

New York-based writer. He holds a doctorate from Harvard University and

was a member of the clinical faculty at New York University Medical

School and Yale University.