Sunday, April 27, 2008
Gene that prolong life after heart failure
About 5 million people in the United States have heart failure, and it results in about 300, 000 deaths each year.
About 40% of African Americans have a genetic variant that can protect them after heart failure and prolong their lives by years, according to research conducted at Washington University School of Medicine in St. Louis and collaborating institutions. This race specific variant has an effect that resembles that of beta blockers, drugs widely prescribed for heart failure.
Adrenaline is a hormone released from the adrenal glands that prompts the fight-or-flight response- it increases cardiac output to give a sudden burst of energy. In heart failure patients decreased blood flow from the struggling heart ramps up, the body’s secretion of adrenaline to compensate for a lower blood flow. Overproduction of the hormone makes the weakened heart pump harder, but eventually worsens the heart failure.
The gene variant present in 40% of African Americans codes for an enzyme called GRK- Lev 41 which depresses the heart’s response to adrenaline in the same way beta blockers do; by blocking adrenaline at its receptor in heart and blood vessels.
Beta blockers prolong life to the same degree as the protective GRK 5 variant, but did not further increase the already improved survival of those with the variant. So, people with this variant can survive without beta blocker therapy as they have nature working for them already.
This discovery adds to the accumulating evidence that genetic differences contribute to the way people respond to medications. In addition it’s also a step toward individualized therapy.
To view the complete article follow the link below.