Background information on presentation by M.R. Malinow, M.D., Oregon Regional Primate Research Center and Oregon Health Sciences University, at AAAS symposium on "Gene-Diet Interactions in Coronary Heart Disease"

Homocysteine (Hcy) is an amino acid generated in the body from the metabolism of methionine, an essential amino acid ingested with food. Homocysteine, normally exported from body cells into blood, occurs in all humans, and probably in all animals. Homocysteine in the blood is the sum of several molecular species, called total homocysteine (tHcy) or homocyst(e)ine [H(e)].

The interest of the scientific community in homocysteine is illustrated by the number of publications dealing with that subject. Figure 1 shows the rate of publications listed in MedLine under Homocysteine/blood since 1966. It indicates that the annual rate of publications has increased about 168-fold in the last 31 years. If such a trend continues, would homocysteine be "the cholesterol of the next century"?

Although it is difficult to know exactly why this surge in interest, it likely stems from the fact that blood concentration of homocyst(e)ine is elevated in 10-40% of people with heart attack, stroke or peripheral atherosclerosis (atherosclerosis in leg blood vessels). Thus, blood homocyst(e)ine may be a risk factor for atherosclerosis, in a similar fashion as smoking, high blood pressure and high cholesterol levels.

Several other reasons for this interest also are probably important. For instance, Figure 2 shows that the risk of death was 6.5 times higher over the course of 4.6 years in patients with coronary heart disease having levels of plasma homocyst(e)ine > 15.0 pmol/L, compared to those patients with homocyst(e)ine below 9 pmol/L.

Figure 3 shows that there is no threshold for the risk of having heart attack according to homocyst(e)ine levels, or as defined more precisely, the risk is graded across the
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Contact: Cathy Yarbrough
cathyy@amhrt.org
214-706-1340
American Heart Association
14-Feb-1998