The Callicam
Current Common Marmoset Research
Current Research - Page 5
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III. Biomedical Research
A) Coronary Heart Disease Model
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Heart disease is the result of deposition of fat or cholesterol in the heart
artery that causes the decrease in blood flow.
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From the heart disease studies of marmosets researchers have begun to notice
beneficial effects of dietary fish oils
Coronary heart disease (CHD) is the most frequent cause of death in the
United States. In 1997, it caused one out of every five deaths. CHD is caused by
an atherosclerotic narrowing of the heart artery.
Atherosclerosis
is the build-up of hardened fat or cholesterol within a blood vessel that causes
the decrease of blood flow. Many health authorities recommend a diet low in
cholesterol as a way to decrease chances of heart disease. Researchers have been
studying dietary components in the common marmoset to try and predict what types
of food will reduce the risks of heart disease. To do this researchers fed the
marmosets diets containing one of the following:
- saturated animal fats
- polyunsaturated fatty acids from marine fish oil
- polyunsaturated fatty acids from plants
- low fat
These diets were tested by comparison of cardiac functions such as heart-rate
(your pulse rate per minute) or systolic blood pressure (the blood pressure
measured while the heart is contracting).
In addition to these tests researchers have developed a way to test the
stability of the heart and its vulnerability to disturbances in its normal
rhythm that cause the heart to pump less effectively. Disturbance in the heart
rhythm is called
cardiac arrhythmia and can be caused when the arteries to the heart are blocked, as
they are in heart disease. Researchers can test the stability of the heart in
marmosets by slowly increasing electrical stimulation to the marmoset heart of
common marmosets until the electrical stimulation causes heart muscle
contractions. The less stable heart will start showing muscle contractions at a
lower electrical stimulation than a stable heart because it is not as strong
and, therefore, not as resistant to electrical disruption. Researchers measure
the impact of diets on the stability of the marmoset heart by employing this
electrical stimulation technique. Animals fed the different diets listed above
were compared on the basis of the electrical stimulation to see how the diets
affected heart function. The hearts that required more stimulation were stronger
than the others. The results implied that the diets of marmosets with more
stable heart rhythms were more beneficial for reducing heart disease and the
abnormal heart rhythms. From these techniques, researchers have begun to notice
an effect of fish oils, obtained from a diet rich in fish, as having a
beneficial and protective effect on heart disease. With continuing research in
this area using marmoset monkeys, perhaps the leading cause of death in the
United States will no longer be CHD.
Further Reading:
Charnock, J. S. (1999). Fish Oil Supplemented Diets and Cardiac Function in
Marmoset Monkeys: A Non-human Primate Model for the Study of Cardiac Arrhythmia.
Nutrition Research, 19 (9), 1429-1435.
McLennan, P. L., Barnden, L. R., Bridle, T. M., Abeywardena, M. Y., &
Charnock, J. S. (1992). Dietary fat Modulation of Left Ventricular Ejection
Fraction in the Marmoset Due to Enhanced Filling. Cardiovascular Research, 26,
871-877.
Additional Related Links:
American Heart Association:
http://www.americanheart.org
Center for Disease Control and Prevention:
http://www.cdc.gov/od/oc/media/fact/cardiova.htm
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Text by Rebecca Dallwig.
