27 Jul 2000

Joseph F. Poduslo and colleagues at Mayo Clinic report in the August issue of Nature Biotechnology (pp. 868-872) on a technique for imaging Aβ deposits in living brain. The approach may allow an earlier diagnosis of Alzheimer's disease, thus opening the door to early therapeutic interventions. Using a transgenic mouse model that develops Aβ deposits, the Mayo scientists showed that neuritic-type plaques can be radioactively labeled. They injected synthetic Aβ labeled with a radioactive isotope of iodine (125I), which crossed the blood-brain barrier and bound to neuritic plaques. Although the results are encouraging, the researchers need to improve plaque labeling efficiency to achieve more widespread plaque labeling, perhaps through experiments with other probes or different types and modification of Aβ protein, and use of 123I, an isotope that is more suitable for diagnostic imaging.—Hakon Heimer