NHLBI Study Finds Possible New Indicator of Heart Disease
Levels of a type of adult stem cell in the bloodstream may indicate a person's
risk of developing cardiovascular disease, according to a study supported
by the National Heart, Lung, and Blood Institute (NHLBI), part of the National
Institutes of Health in Bethesda, MD.
The study looked at the blood level of endothelial progenitor cells, which
are made in the bone marrow and may help the body repair damage to blood vessels.
Scientists from NHLBI and Emory University Hospital in Atlanta, GA, found
that cardiovascular disease risk was higher in persons with fewer endothelial
progenitor cells. The cells of those at higher risk also aged faster than
those at lower risk, as determined by the Framingham Heart Study risk factor
score, a standard measurement of cardiovascular risk. Additionally, the study
found that blood vessels were much less likely to dilate and relax appropriately
in persons with low levels of the cells.
Results of the study, which involved 45 healthy men aged 21 and older, some
of whom had standard cardiovascular risk factors, appear in the February 13,
2003, issue of The New England Journal of Medicine. The two main forms
of cardiovascular disease are heart disease and stroke. Standard heart disease
risk factors are age, family history of early heart disease, smoking, high
blood pressure, high blood cholesterol, overweight/obesity, physical inactivity,
"Past research on cardiovascular disease has often focused on what causes
the damage to the blood vessels," said Dr. Toren Finkel, chief of NHLBI's
Cardiology Branch and coauthor of the study. "We looked at the other part
of the equation: How does the body repair damaged blood vessels? What does
that tell us about the cause of the disease?
"We believe that these endothelial progenitor cells patch damaged sites in
blood vessel walls," he continued. "When the cells start to run out, cardiovascular
disease worsens. We don't yet know what causes their depletion but it may
be related to the fact that the risk of cardiovascular disease increases as
people age. For instance, the cells may be used up repairing damage done by
other risk factors or those risk factors could directly affect the survival
of the endothelial cells themselves.
"Much more research needs to be done to better understand this finding,"
Finkel added. "But it's possible that, some day, doctors may be able to test
a person's risk of cardiovascular disease by taking a blood sample and measuring
these cells. If the level is too low, an injection of endothelial cells might
boost the body's ability to repair itself and prevent more blood vessel damage."
Finkel is available for comment on the study. To arrange an interview, call
the NHLBI Communications Office at (301) 496-4236.
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