New studies suggest that novel [18F] ligands used with positron emission tomography (PET) may shed important light on the neural basis of memory impairment in the preclinical stages of Alzheimer's disease (AD).
Keith A. Johnson, MD, professor, radiology and neurology, and co-leader, Neuroimaging Program, Massachusetts Alzheimer's Disease Research Center, Harvard Medical School, Boston, Massachusetts, reported results for an initial small series of patients with and those without cognitive impairment imaged using one of these agents, T807, during the 6th Clinical Trials conference on AD (CTAD).
There are reasons to believe tau imaging may eventually be an even better tool for determining cognitive impairment than amyloid imaging, and that is what they are trying to determine with this work, Dr. Johnson told Medscape Medical News.
There's long been a suggestion in the literature that tau tangles "are actually closer to the action in the sense that when you see them, they relate more closely to the cognitive status of the subject," he said.
Together with amyloid-β (Aβ) plaques, tau neurofibrillary tangles represent the hallmark neuropathologic signs of AD. Both appear many years before the onset of symptoms of clinically evident cognitive impairment. A normal component of nerve cells, tau helps to stabilize the internal neural transport system and supports the architecture of neural cells.
"Under certain circumstances, the protein is transformed chemically for reasons we don't understand and begins to accumulate in abnormal forms," Dr. Johnson told Medscape Medical News. This transformation is associated with the cell death that is seen in many tau pathologies, with AD being just one of them.