Regression of coronary atherosclerosis

Article Abstract:

Evaluation of ways to slow the progress of atherosclerosis, the deposition of fatty plaque on arterial walls, has been hampered by variability among animal models of the disease, as well as by the difficulty of evaluating atherosclerosis in living people. A study in the November 8, 1990 issue of The New England Journal of Medicine reports that drug therapy aimed at reducing cholesterol levels led to a reduction in those levels, as well as a reduction in the number of clinical events, such as death and heart attacks. Another report showed that partial ileal bypass (a surgical procedure performed to shorten the intestine, affecting the absorption of nutrients) also improved cholesterol levels. These two studies are discussed and evaluated. The drug study measured not only blood cholesterol levels, but also changes in the amount of stenosis (narrowing) of the coronary arteries, which supply blood to the heart. The actual changes, while statistically significant, were quite small. Quantitative angiography, measurement of coronary arteries on X-rays taken after the injection of dye into the vessels, has drawbacks that should be considered when such studies are interpreted. One is the need for a 'reference' vessel for comparing arteries that may have changed after a treatment. The reference vessel itself, however, may also undergo atherosclerotic change in a person subject to the disorder. Constriction of the coronary arteries can occur as a result of factors other than atherosclerosis. It is not clear that the type of coronary lesion that improves after drug treatment is the same type that causes heart attacks. In spite of the problems that can be raised in connection with the two studies, the benefits of these treatment approaches are clear. (Consumer Summary produced by Reliance Medical Information, Inc.)

Care and treatment, Evaluation, Measurement, Blood lipids, Coronary arteries

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Nitric oxide and vascular disease

Article Abstract:

Decreased levels of nitric oxide play an important role in the progression of high blood pressure in the lungs, known as pulmonary hypertension. Nitric oxide is produced by the enzyme nitric oxide synthase in the cells lining blood vessels. Nitric oxide causes the dilation of blood vessels by causing smooth muscles in the vessels to relax. Nitric oxide also stimulates growth of blood vessel cells and inhibits clotting. A 1995 study found that patients with pulmonary hypertension had low levels of nitric oxide synthase in the cells lining their blood vessels. However, it remains unclear whether low nitric oxide synthase levels are a cause or a result of pulmonary hypertension. In any case, worsening function of the blood vessel cells probably helps advance the disease. Furthermore, inhaling nitric oxide has been shown to lower blood pressure in the lungs and may lead to effective ways of treating pulmonary hypertension.

Editorial, Peripheral vascular diseases, Nitric oxide, Pulmonary hypertension

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Homocysteine and atherothrombosis

Article Abstract:

The level of homocysteine and related substances in the blood may be associated with the risk of coronary artery and other vascular diseases. Homocysteine is an amino acid formed during protein metabolism. Genetic defects, diseases, medications, and dietary deficiencies in folate and B vitamins can cause an elevation in total homocysteine levels, which may increase the risks of heart disease, heart attack, and stroke. Researchers think that homocysteine damages the lining of blood vessels, promoting the formation of clots and blockages. Dietary folic acid may reduce this risk.

Risk factors, Folic acid, Homocysteine

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