Quintet of proteins forms new, early-warning blood test before heart atta...( (Sunday Morning Program Presentation...),Health

(Sunday Morning Program, Presentation #183, Room #283-285, Ernest N. Morial Convention Center)

A team of Johns Hopkins biochemists has identified a mixed bag of five key proteins out of thousands secreted into blood draining from the heart's blood vessels that may together or in certain quantities form the basis of a far more accurate early warning test than currently in use of impending heart attack in people with severely reduced blood flow, or ischemia.

The work, involving more than a dozen scientists and taking more than a year to perform, is believed to be the largest protein analysis ever done at Hopkins. It was based on 76 arterial blood samples from 19 men and women taken immediately before and after a period of medically induced ischemia lasting as long as 45 minutes.

All had ischemia induced through accelerated pacing of the heart's main chambers. Blood samples were provided by cardiologists at the University of Texas Southwestern.

Key to the researchers' selection criteria for which proteins to analyze from among tens of thousands in the blood was what they call "a pipeline approach."

"From the start, we knew that we were looking for rare, almost unique biomarkers that bore some direct relationship with ischemia," says study senior investigator Jennifer Van Eyk, Ph.D., whose first step was to remove from the analysis common blood proteins, such as albumin and globulins. That left batches of 400 proteins for in-depth measure of any changes before and after ischemia.

Their analysis, to be presented Nov. 9 at the at the American Heart Association's (AHA) annual Scientific Sessions in New Orleans, found that only the five proteins were present in significantly increased amounts after ischemia occurred, with at least a doubling in the blood concentration, compared with those recorded during healthy blood flow. These were lumican, semenogelin, angiogenin, extracellular matrix protein, and
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