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PHILADELPHIA -- The most common strain of
bacteria in dental plaque can cause blood clots that induce heart attacks when
they escape into the bloodstream, researchers reported Monday.
Mark Herzberg of the University of Minnesota said the findings
are the first to link bacteria to the formation of potentially fatal blood
clots.
Previous studies had found the incidence of heart disease is about twice as
high in people with periodontal disease, but scientists didn't know why.
``Now we show a potential biological reason,'' Herzberg told
the 150th annual meeting of American Association for the Advancement of
Science.
In lab tests, Herzberg and colleagues injected bacteria from
dental plaque into the bloodstream of rabbits. The bacteria caused blood clots
to form within minutes. Rabbits are a proven model for testing hypotheses about
human heart disease and heart attacks.
Chronic inflammation of the gums due to plaque also could be
involved in the inflammation of the lining of the blood vessels that is known to
lead to the build-up of plaque in the arteries, Herzberg said.
Additional studies presented at the meeting show that bacteria in plaque also
are linked to:
• A potentially fatal disease called infective
endocarditis in which the sac around the heart becomes
inflamed.
• Lung infections in people
with chronic lung diseases such as chronic obstructive pulmonary
disease.
• A weakened immune system that can slow wound
healing and diminish a person's response to vaccines against
hepatitis B and influenza.
• A higher risk of giving birth to premature, low-birth
weight infants.
Reducing risk of diseases linked to dental bacteria is a
common lesson preached by dentists: Have the teeth cleaned regularly and floss
daily. If necessary, have bone implants to replace dental bone lost from
periodontal disease, says researcher Frank Scannapieco, State University of New
York, Buffalo. Bacteria reside in pockets caused by bone loss where the teeth
are attached.
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