DEVELOPING THE POTENTIAL:
DIAGNOSTIC FLUID OF THE FUTURE
(Health & Human Development - A Magazine
for Alumni & Friends - Fall 1999)
Steve Infanti
If Dr. Douglas Granger's research is successful, it may be possible in the future to screen for diseases and behavioral problems with a simple sample of saliva.
From health monitoring to drug testing, saliva could become the diagnostic testing fluid of the future. It could revolutionize medical care and its impact could be felt everywhere from medical clinics to businesses interested in monitoring employees' health.
Parents won't have to subject their children to painful blood tests. Rather than go through invasive exams to test for cancer or HIV, patients could just submit a saliva sample. A simple swab of a patient's saliva could be used to screen for everything from cancer to how a child may develop emotionally. It could someday provide an easy, cost-effective method for businesses to test for drugs or for insurance companies to check an applicant's health. "The practical implications of using saliva as a diagnostic fluid are enormous," says Granger. The assistant professor of biobehavioral health has been at the forefront of research on saliva testing. He's also director of Penn State's Behavioral Endocrinology Laboratory.
The laboratory specializes in the design of assays and testing saliva samples for all different kinds of biological markers. These markers are hormonal indicators of changes in the body. Technicians sort through thousands of small tubes, frozen at ultra-cold temperatures that come from as far away as Sweden and Australia for analysis. This research and service laboratory is also unique because it is the first university lab to be located in the new Penn State Research Park.
One of the first applications has been to screen for HIV infection. In the future, it is possible that saliva might be used to diagnose other infections and possibly cancer, says Granger.
"Collecting saliva is considerably less intrusive, painful and inconvenient for the donor than blood or urine samples. It can also be used for testing populations that aren't easy to test using blood, such as infants, hemophiliacs, and those who feel squeamish or uncomfortable with blood," says Granger.
Gathering samples is a simple process, too. The person giving the
sample typically spits into a tube.
The Behavioral Endocrinology Laboratory has become the leader in this research. It focuses exclusively on salivary biomarkers and the integration of these measures into research in health and human development. The laboratory facilitates projects at the cutting edge of biobehavioral science that involve interdisciplinary research collaborations. The laboratory is currently supporting the studies of more than sixty investigators at major research universities throughout the world.
Ten undergraduate students are expected to take part in hands-on biobehavioral research each semester, and Granger also hopes the laboratory can offer some undergraduate research fellowships in the future.
The laboratory is an interesting case study in university facilities because it is an example of the ultimate "shared" lab, notes Granger. It is supported entirely by user fees assessed to the investigators worldwide who use the unit each year. It is like a giant co-operative. Saliva testinghas been slow to catch on in the United States, but Granger believes that is changing.
"Once more people see the benefits of using saliva instead of blood, they'll convert," says Granger.
Although drug testing is perhaps the most obvious use of saliva tests for employers, saliva could be a means to measure employee stress by testing for stress-related chemicals, such as cortisol. In order to do that, however, the Food and Drug Administration would have to approve the tests as a diagnostic to test for stress levels in jobs, says Granger.
Companies could also use saliva testing while doing trials for new products. For instance, testing nicotine patches requires multiple samples of a biological fluid. With saliva testing, product developers could monitor hormonal changes every day so they can fine-tune dosages, explains Granger.
Granger and other researchers in the laboratory are working on various projects that can have major health implications. Saliva tests can be used to measure testosterone levels. Higher levels of testosterone have significant health benefits for some middle-aged men.
Men with higher testosterone are less vulnerable to high blood pressure, heart attacks, frequent colds and obesity. In addition, they are more likely to rate their health as excellent or good rather than fair or poor.
Studies show self ratings of health correlate highly with physicians' assessments. However, some, but not all, men with higher levels of testosterone are more likely to engage in behavior that cancels out the beneficial effects of testosterone, such as being more likely to smoke.
Granger is also using saliva assays to test cortisol levels. Cortisol is a hormone linked to stress, anxiety, depression, and socially withdrawn behavior. Granger has shown in past research that children who are more socially withdrawn or anxious are more likely to have an increasedlevel of cortisol in their bodies. This is in response to stresses like social conflicts with their parents. Other research has shown that high levels of cortisol are associated with changes in the immune system, emotional problems, and perhaps memory impairments.
Granger and his colleagues at the laboratory are also studying DHEA (dehydroepiandrosterone) levels in children and adults.
"Many people look at DHEA as a supplement to enhance aspects of their cognition, mood, and health," explains Granger. Research also shows that DHEA plays a key role in the physiology of stress, is associated with major developmental milestones during middle childhood that set the stage of the transition to puberty, and DHEA is the major precursor of testosterone in females.
The researchers also recently discovered that DHEA can be accurately measured in saliva. This is important, Granger says, because researchers can now monitor the levels of this hormone in people's everyday social worlds. By studying hormones and behavior in social context, researchers expect to learn new information about how biology and behavior interact with the environment to produce differences in developmental and health outcomes.
"We're just starting to see the impact this research can have on the quality of our lives," says Granger. He even co-founded a State College-based company, Salimetrics, that is the first in the world devoted exclusively to saliva testing. Currently, the company markets to researchers around the world who are interested in analyzing saliva samples for biological markers. The company offers saliva-testing kits, a full line of analytical controls for saliva, consultation to help researchers properly collect saliva, and a facility to test saliva.
"Saliva testing is readily accepted in Europe and it is just a matter of time before it catches on in the U.S.," says Granger.