WASHINGTON, DC - The doctors may have demonstrated why a common drug given to patients with heart failure fails to help nearly half of them: a genetic difference resulting in a change of a single amino acid appears to determine patient response to the drug. The results, announced today at the annual meeting of the American Association for the Advancement of Science, could help doctors better prescribe medication for patients with heart failure, and perhaps for those with pressure high blood well.
In the late 190s, Stephen Liggett pulmonologist from the University of Cincinnati, and his colleagues have identified a genetic variation in humans has not been seen in a variety of species, including mammals, suggesting that it has recently evolved in humans. The change occurs in a single amino acid - Humans or arginine or glycine. Everyone has two copies, inheriting one from each parent; This means that a person may have two copies of glycine, arginine, two, or one of each. Studies have suggested that mice with two copies of arginine were more susceptible to heart failure and more sensitive to beta blockers -. A class of drugs used to treat
Liggett decided to test how this affected human variation. His team found 1,040 volunteers, all people with severe heart failure. Almost half had either two copies of arginine or an arginine and a glycine; the rest had two copies of glycine. Patients were randomized to receive either a placebo or the drug bucindolol, a beta-blocker.
When observed for about 2 years (and in some cases up to 5), 82% survived to drugs, compared to 65% compared to placebo. Those with one copy of each amino acid or two copies of glycine, however, have not helped at all by drugs, fare nearly as badly as placebo. Liggett hopes to establish a larger study to see if the results are robust. All patients received the drug because he believes that the results show that it is unethical to give patients arginine double copy placebo
"He found a polymorphism." - Genetic variation - "that seems to predict response" to bucindolol says Kathy Giacomini from the University of California, San Francisco. The result, she says, is "very exciting" and "very specific." We do not know, Liggett said, if the results are applicable to other beta-blockers, which are also used to treat high blood pressure.
related site
homepage Liggett
0 Komentar