Your saliva could hold clues about health problems

The next time you spit, consider this: Your saliva might one day be used to diagnose or prevent a heart attack.

PHOTO BY RICARDO B. BRAZZIELL / COX NEWS SERVICE University of Texas professor John McDevitt is the co-inventor of nanochip technology that he hopes will be on board ambulances in a few years to diagnose heart attacks. If research by scientists and dentists in Texas and Kentucky bears out, in several years, heart attack patients could be diag- nosed in an ambulance by analyzing a few drops of saliva, saving precious time at the hospital, researchers said.

"It could save time - and lives," said Dr. Chris Ziebell, chief of emergency medicine at University Medical Center at Brackenridge in Austin, Texas.

Right now, heart attacks can be diagnosed in the ambulance with an electrocardiogram with the results transmitted by cellphone. But less severe heart attacks can be missed by EKGs, requiring blood tests that now take more than two hours at the hospital, Ziebell said. The spit test would take 15 minutes in the ambulance, said John McDevitt, a University of Texas chemistry professor who is spearheading the new research.

He envisions ambulances being equipped with a toaster-size LabNow computer that he designed to analyze the saliva, which would be placed on a small computer chip embedded in a credit-cardsized device. The LabNow computer - initially designed to diagnose AIDS patients in Africa - would spit out the results, showing whether certain chemicals or cardiac enzymes are high, indicating a heart attack, he said.

As far as the researchers know, no one else has discovered the heart disease markers in saliva. The team, which unveiled the research at a dental research meeting in Dallas recently, has found similar uses for saliva in diagnosing several cancers affecting women: uterine, cervical and breast, McDevitt said.

"Saliva's been a poor cousin to whole blood and serum" as a tool for diagnosing diseases, said McDevitt, a shareholder in the LabNow company developing the computer. But many of the same disease markers that "you can see in blood, you can see in saliva," he said. "You just have to look for it harder."

The team found 32 chemicals, or proteins, in saliva that are known to be related to heart activity, McDevitt said. Of those, the team studied eight that were significantly elevated during a heart attack and narrowed that to four that were "the most diagnostic of a heart attack," said Dr. Craig Miller, a professor of oral dentistry at the University of Kentucky College of Dentistry in Lexington, Ky.

Because most of the 56 heart attack patients in the researchers' study, which is being prepared for publication in peer-reviewed journals, had their saliva analyzed within 24 to 48 hours after the heart attack, the team needs to find out whether those same markers can be detected within minutes to hours of a heart attack. That's crucial information, said Dr. Blase Carabello, a cardiologist and chief of medicine at the Michael E. DeBakey VA Medical Center in Houston.

If McDevitt's team is right about saving time, "that's great," Carabello said. But he said ambulances could just as easily be equipped with laptop-size analyzers that also can detect high levels of proteins in blood indicating a heart attack. He added that the researchers still need to prove their findings through clinical studies.

The saliva technology will be road-tested in San Antonio ambulances this summer, said a collaborator, Dr. Spencer Redding, professor and chairman of the Department of Dental Diagnostic Science at the UT Health Science Center at San Antonio.

They think that the high cardiac enzymes they found in saliva in patients having a heart attack also might be present in people at risk of a heart attack. They have asked some of the 56 heart attack victims in the study to freeze their saliva over the next six months so it can be tested, Miller said.

"About 15 percent of the people who had a heart attack will have another heart attack in six months," Miller said.

The good news, Redding said, is that there's lots of saliva. The average person, he said, makes about a quart of saliva a day while talking, eating and drooling on the pillow at night.