The new study contradicted the expectations of researchers, who were hoping to learn why brain injury is linked to higher risk of Alzheimer's disease, as they found recovery from brain injury, rather than the injury itself, seemed to increase amyloid.
"Proving that we can directly measure amyloid beta in the human brain is an important step forward for both clinical and basic research, and that may be true not just in Alzheimer's disease but also in other serious neurological disorders," said co-first author David L. Brody, M.D., Ph.D., a Washington University.
During the study, the researchers were measured the amyloid beta levels wit the help of a technique called microdialysis that involves placing a small catheter into the brain tissue to sample the fluid in the spaces between cells.
The Italian group, headed by Sandra Magnoni, M.D., and Nino Stocchetti, M.D., and located at the Ospedale Maggiore Policlinico, a major trauma centre in Milan, brought substantial previous experience with microdialysis to the study.
In the study, 18 patients recovering from traumatic brain injuries or ruptured brain aneurysms had microdialysis catheters placed in their brain tissues to measure amyloid beta while they were in the intensive care unit.
"The results have potentially important clinical implications because the measurement of amyloid beta in the human brain may turn out to be a good indicator of how well brain cells are communicating with each other, even in very sick patients," said senior author David M. Holtzman, M.D., the Andrew B. and Gretchen P. Jones Professor and head of the Department of Neurology at Washington University.
"If the results are validated in further studies, this may assist physicians in making important patient management decisions in patients with acute neurological disorders," he added.