Study Links Zinc to Brain Damage
Schieszer, John, St Louis Post-Dispatch (MO)
Scientists have long wondered why about half the people resuscitated after their hearts stop beating end up with brain damage. Now, Washington University researchers have found the answer: zinc.
The investigators, led by Dr. Dennis Choi, have already devised a way of preventing zinc damage in the brain. Their findings may pave the way for preventing brain injury in hundreds of thousands of patients in the future.
"This is an important study," said Choi, head of the medical school's neurology department. "This identification raises new questions and ideas that were never raised before."
Every year, hundreds of thousands of Americans suffer cardiac arrest in which their hearts simply stop beating. About 250,000 sudden cardiac deaths occur each year. Although tens of thousands have their hearts restarted, about half end up with symptoms of brain damage.
"We believe that zinc is killing the cells (in the brain). It is the mediator," said Choi, who reports his findings in Friday's issue of Science magazine.
When the heart stops beating, the supply of blood to the brain dwindles, prompting a cascade of molecular events that harm brain cells. Until now, neurologists have been at a loss to explain why cardiac arrest damages some parts of the brain and not others even though the entire brain runs short of blood. Choi and his team believe the release of zinc causes damage to the region of the brain known as the hippocampus, which is involved in learning and memory, and the amygdala, which plays a role i n emotion. …