Cerebrospinal Fluid Biomarker Could Help Identify Early Alzheimer’s Disease
A new study out of Michigan points to the pro nerve growth factor (proNGF) as a possible biomarker that could aid in the diagnosis of early Alzheimer’s disease (AD). The article, “Cerebrospinal fluid proNGF: A putative biomarker for early Alzheimer’s disease,“ appeared in the journal Current Alzheimer’s Research.
AD is a degenerative neurological condition in which neurons die in regions that process memory such as the hippocampus and cerebral cortex. Current treatments serve only to marginally delay the onset of disease symptoms, which includes memory loss. New methods for identifying early Alzheimer’s disease could aid in treatments that prevent neuron loss from occurring in the first place. Biomarkers, including those found in the cerebral spinal fluid that bathes the brain, may be helpful for aiding in early diagnosis.
Researchers have already identified increases in the proteins beta-amyloid and phosphorylated tau in the cerebrospinal fluid of people with AD. Both of these molecules likely contribute to the brain cell death found in AD. Additional markers may further aid in early identification of Alzheimer’s disease, such as nerve growth factor (NGF), a molecule produced by neurons that also helps them survive.
Researchers led by Scott E. Counts of the Department of Translational Science and Molecular Medicine at Michigan State University tested whether different levels of an NGF-related protein (proNGF) could be measured in the cerebrospinal fluid (CSF) of people with Alzheimer’s disease. They used a standard test known as an immunoblot to measure pro nerve growth factor in CSF taken from people with early signs of Alzheimer’s: no cognitive impairment; some cognitive impairment (possible pre-Alzheimer’s); and mild or moderate Alzheimer’s.
In the pre-AD group, pro nerve growth factor increased by 55 percent compared to the group with no cognitive impairment, and by 70 percent in the group with AD. They also found higher levels of the pathological Alzheimer’s protein beta-amyloid in the cerebrospinal fluid of people with pre-Alzheimer’s and Alzheimer’s disease, but did not find higher levels of the Alzheimer’s protein phosphorylated tau. They also failed to find any differences in a different growth factor, known as brain-derived neurotrophic factor (BDNF).
“Taken together, these results suggest that proNGF protein levels may augment the diagnostic accuracy of currently used CSF biomarker panels,” the authors wrote in their study.
The research suggests that pro nerve growth factor might be an additional diagnostic tool to help physicians identify Alzheimer’s at an earlier stage, possibly leading to better interventions that could prevent the progression of the disease.