Scientist Tries to Restrain Platelets That Form Killer Clots and Help Spread Cancer

Platelets, the blood cells that help a cut finger stop bleeding, can also take a deadly turn as they course through veins and arteries. When platelets in the bloodstream clump together as a clot, they can trigger a heart attack or a stroke. When platelets stick to a moving cancer cell, they may hide it from the body's natural defenses.

A Johns Hopkins University scientist is working on ways to disable platelets' unhealthy habits while preserving their ability to halt blood loss. The goal, says Konstantinos Konstantopoulos, is to unlock the secrets of the tacky molecules that platelets use to cling to each other and to the walls of blood vessels.

To do this, Konstantopoulos, an assistant professor of chemical engineering, has set up equipment that simulates the flow of human blood beneath a microscope. A video camera attached to the microscope lets him record and study cells that are moving as they would through blood vessels. With this equipment, he has begun testing medications that could keep platelets from using their stickiness in ways that jeopardize human health.

Under normal conditions, platelets simply circulate through the body along with red and white blood cells, posing no threat. "If you look inside the blood vessels of a healthy person, you'll see the platelets moving passively without interacting with each other or with the walls of the blood vessel," Konstantopoulos explains.

If the skin is cut, sticky molecules appear on the surface of the platelets, which rush to the site and adhere to the broken vessel wall to prevent blood loss. But sometimes, a medical disorder can set off the sticky response. If these platelets stick to each other and form a clot that stops critical blood flow to the heart or the brain, cardiac arrest or a stroke may occur. This leaves researchers with a challenge: Can pla
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Contact: Phil Sneiderman
prs@jhu.edu
(410) 516-7160
Johns Hopkins University
25-Aug-1998