A report in the February issue of Archives of Neurology, one of the JAMA/Archives journals states that increases in brain cortical binding of the chemical marker called [18F]FDDNP were related to increases in clinical symptoms of neurodegeneration, whilst regional baseline values of this marker seem to be linked to with future cognitive decline.
The researchers explain:
“Nearly 20 percent of people 65 years or older have mild cognitive impairment (MCI), and 10 percent have dementia. Such a high prevalence has led to recent research on the development of brain imaging tools to track the neuropathologic changes associated with these conditions.
Previous cross-sectional studies have shown that [18F]FDDNP brain binding patterns correspond to the known neuropathologic deposition patterns determined from autopsy studies.”
Gary W. Small, M.D., and colleagues with the David Geffen School of Medicine at the University of California, Los Angeles, analyzed 43 individuals aged between 40 to 87 years old (22 patients with normal aging and 21 patients with mild cognitive impairment [MCI]), in order to evaluated if baseline [18F]FDDNP binding values are predictors of future cognitive decline, and if brain regional binding values increase as cognitive decline progresses.
Among participants in the MCI and normal aging group, the researchers measured longitudinal [18F]FDDNP positron emission tomography (PET) binding values in specific regions of the brain.
At the two-year follow up, the researchers discovered that individuals in the MCI showed considerably increases in [18F]FDDNP binding values in parietal, frontal, global and posterior cingulate regions of the brain, although levels in the medial temporal region did not considerably increase.
In addition, frontal and parietal [18F]FDDNP binding among individuals in the MCI group, showed the greatest diagnostic accuracy in detecting individuals at highest risk of developing Alzheimer’s disease than individuals who were not at risk of converting after two years. The researchers found no considerable binding increases in any region of the brain among individuals in the normal aging group.
Furthermore, the team found that among all participants, increases in global, frontal and posterior cingulate binding at follow-up were linked to progression of memory decline after 2 years. In addition, they found that higher [18F]FDDNP binding at baseline was connected with future decline in most cognitive domains including attention, visuospatial, language and executive abilities.
The researchers conclude:
“Our findings indicate that in vivo regional [18F]FDDNP binding patterns are consistent with known patterns of disease deposition and associated with future disease course. Using [18F]FDDNP PET may not only assist in predicting future cognitive decline and identifying individuals more likely to benefit from prevention treatments, but it may also track the effectiveness of such treatments to accelerate drug discovery efforts.”
Written by Grace Rattue