The recently developed radiopharmaceutical carbon 11-labeled Pittsburgh Compound B ([ 11 C]PiB), has enabled researchers to image fibrillar (fiber) forms of the β-amyloid (Aβ) protein.
Susan M. Landau, Ph.D., at the University of California in Berkeley and the Lawrence Berkeley National Laboratory, and her team performed [ 11 C]PiB PET (positron emission tomography) and neuropsychological testing in a sample of cognitively normal older participants. The researchers defined Aβ as average cortical [ 11 C]PiB PET uptake. They assessed 65 healthy elderly people, with an average age of 76.1 years, and compared them with 11 young participants, with an average age of 24.5 years, and 10 patients with Alzheimer disease (AD) aged on average 74.8 years. The researchers surveyed all participants in terms of their different lifestyle practices, including the frequency in which they participated in cognitively engaging activities at different phases throughout their life, starting from the age of 6 years to their current age.
"We report a direct association between cognitive activity and [ 11 C]PiB uptake, suggesting that lifestyle factors found in individuals with high cognitive engagement may prevent or slow deposition of β-amyloid, perhaps influencing the onset and progression of AD."
According to the findings, a greater participation in cognitively stimulating activities throughout a person's life, particularly in early and middle life, seems to be linked to reduced [ 11 C]PiB uptake. The researchers noted that the [ 11 C]PiB uptake was similar between elderly individuals with the highest cognitive activity and young people in the control group, whilst those with the lowest cognitive activity had [ 11 C]PiB uptake similar to AD patients.
The researchers note that even though a greater cognitive activity was linked to more physical exercise, it was not linked to [ 11 C]PiB uptake. They indicate that the likelihood of engaging in cognitively stimulating activities tends to be linked to various lifestyle practices, which have been implicated in other studies with a decreased risk of AD-related pathology.
The researchers conclude:
"It is unlikely that our results reflect a single unitary cause of AD, which is a complex disease with many potential pathogenetic processes. Furthermore, cognitive activity is just one component of a complex set of lifestyle practices linked to AD risk that may be examined in future work. However, the present findings extend previous findings that link cognitive stimulation and AD risk (an indirect downstream effect of Aβ) by providing evidence that is consistent with a model in which cognitive stimulation is linked directly to the AD-related pathology itself."
Written Petra Rattue