March 25, 2008

Saliva Could Replace Blood in Disease Testing

Human saliva could replace blood in future diagnostic testing procedures due to recent U.S. research.

The collaboration of researchers of five universities reported on Tuesday that it has cataloged all 1,116 unique proteins found in human saliva glands, approximately 20 percent of which are also found in blood, said Fred Hagan, a researcher at the University of Rochester Medical Center in New York who worked on the study.

Researchers hope the results will usher in a new wave of saliva-based testing to diagnose a wide array of conditions including cancer, heart disease and diabetes.

"This is potentially a large field that has many clinical implications in the area of disease diagnostics," said Hagan.

"To be able to diagnose disease using saliva, you really have to have a comprehensive understanding of the saliva proteome."

The proteome is a complete map of proteins expressed by a genome, cell, tissue or organ. Proteins carry out actions given by genes to regulate cellular processes.

"Past studies established that salivary proteins heal the mouth, amplify the voice, develop the taste buds and kill bacteria and viruses," said James E. Melvin, D.D.S., Ph.D., director of the Center for Oral Biology at the University of Rochester Medical Center, and an author of the paper.

"Our work, and the work of our partners, has shown that salivary proteins may represent new tools for tracking disease throughout the body"”tools that are potentially easier to monitor in saliva than in blood."

By comparing saliva samples collected from 23 healthy men and women with recent protein maps of human blood and tears, researchers found a number of proteins related to the body's response to a variety of diseases.

Saliva-based tests to detect HIV and hepatitis infections already exist, Hagan said, adding that he hopes the new research will allow for the development of new ways to track other diseases in the body.

"Monitoring disease as well as drug use could be more easily done with saliva as opposed to blood or urine," he said.

Another test by a separate group seeks to test for breast cancer by locating a protein fragment from the HER2 protein is already under way.

"We envision in the future spitting in a tube and looking for a marker like this breast cancer marker. It would be much easier to do, potentially at home," he said.

"Given that we've made this information publicly available, we fully expect a number of research groups will be picking their favorite targets and developing their own tests. That is the intent -- to create a wealth of data to stimulate more research and increase the chances of producing better diagnostic tests," Hagan said.

Results were published in the Journal of Proteome Research.


On the Net:

University of Rochester Medical Center

Journal of Proteome Research