Originally Published MDDI February 2002
R & D DIGEST
Researchers speculate that the ability to detect and monitor Alzheimer's disease (AD) as it unfolds would speed diagnosis and aid in intervention. It would also enable the use of new therapies for the disorder, which is estimated to afflict 10% of people older than 65. Now, researchers at the University of California, Los Angeles have combined use of a new chemical marker called FDDNP with positron emission tomography (PET) to see for the first time the brain lesions indicative of AD in living patients.
According to principal investigator Jorge R. Barrio, MD, UCLA professor of medical and molecular pharmacology, "We have developed the first tracer molecule that visually zeroes in on the brain lesions caused by Alzheimer's disease." Coinvestigator Gary Small, Parlow-Solomon Professor of Aging and UCLA professor of psychiatry and biobehavioral sciences, explains that the "noninvasive method will help us monitor new vaccines and drugs designed to prevent and treat the brain damage caused by Alzheimer's disease."
Using PET, Barrio and Small detected high concentrations of FDDNP in the memory centers of nine Alzheimer's patients' brains. To verify their findings, they performed a brain autopsy after one of the patients died. The postmortem tissue revealed that FDDNP-stained lesions were present in the brain's memory centers, thus confirming the results of the patient's PET scan.
Barrio and Small also discovered that PET scans of patients injected with FDDNP showed the presence of early brain lesions, before the plaques are believed to destroy brain cells. The researchers believe that if current hypotheses about the role of lesions in the disease process prove accurate, the technique may be capable of identifying when medical intervention can delay or prevent the onset of the disease.
Conventional methods for making a definitive Alzheimer's diagnosis require that pathologists conduct a brain autopsy. As a result, physicians are only able to treat Alzheimer's disease after the disease has caused apparent damage to the patient's memory. Such symptom-based diagnoses produce accurate results only 55% of the time. According to Small, "Most forms of dementia clinically look the same. But if we can pinpoint the specific form of dementia, we can use the appropriate medication to postpone onset of the disease."
"Combining the FDDNP marker with PET scans will enable us to better screen participants for clinical trials and produce more-accurate research results," Barrio adds. "This will bring new drugs to market faster with lower cost and improved accuracy for patients."
Barrio's and Small's next step will be to refine the FDDNP–PET scan technique to enable monitoring of treatment with therapeutic drugs. The research team is comparing the PET scans of a larger group of Alzheimer's patients with those of unaffected individuals and patients with other dementias.
Copyright ©2002 Medical Device & Diagnostic Industry