These days, it is common to know of someone suffering from, or affected by Alzheimer’s disease. That is because it is the leading cause of dementia, and affects more than 5 million people in the United States alone (Kirkwood et al, 2016). Alzheimer’s disease occurs when there is progressive degeneration of specific neurons in the brain, and results in memory loss, a decline in cognitive function, and behavioural changes; all which worsen as the disease progresses. There is still much to learn about this devastating disease that affects so many people, and research on the disease is continually ongoing.
One study by Kirkwood et al. (2016) focused on the expression of the neuronal calcium-sensing protein Vilip-1 in the brains of people with Alzheimer’s disease. Previous studies have indicated that Vilip-1 may be a peripheral early stage biomarker for the disease. A biomarker is a substance whose presence indicates the occurrence of a disease or infection. Kirkwood et al. (2016) were interested in how the expression of Vilip-1 in certain brain tissues is associated with neuronal loss. In their study, they focused on Vilip-1 levels in two brain regions which have varying levels of neuronal loss in early to moderate stage Alzheimer’s patients. These regions were the entorhinal cortex (ERC), which is located in the temporal lobe, and the superior frontal gyrus (SF), which is located in the frontal lobe. They looked at these brain regions in patients with early to moderate stage Alzheimer’s disease, frontotemporal lobar degeneration (FTLD), and normal elderly controls. In early stage Alzheimer’s, the ERC has greater neuronal loss, while in FTLD there is more neuronal loss in the SF.
The researchers used targeted and quantitative mass spectrometry to measure the Vilip-1 levels in the different brain regions. They found that there was a significant decrease in Vilip-1 levels in the ERC of Alzheimer’s patients, but no difference in Vilip-1 levels in the SF when compared to the normal control group. This means that the levels of Vilip-1 were decreased in the brain region where more neuronal loss had occurred. In the patients with FTLD, they found decreased levels of Vilip-1 in the SF brain region, which is the region that has more neuronal loss in FTLD cases. These results supported that Vilip-1 levels are altered in Alzheimer’s patients, and are associated with neuronal loss. In addition to the decreased levels of Vilip-1 in the ERC, Vilip-1 levels were elevated in the cerebral spinal fluid of Alzheimer’s patients. Kirkwood et al. (2016) concluded that Vilip-1 is released upon neuronal death in the ERC, and diffuses from the interstitial fluid of the ERC into the cerebral spinal fluid. Simply put, a decrease of Vilip-1 in the ERC results in an increase of Vilip-1 in the cerebral spinal fluid.
These results indicate that the presence of elevated levels of Vilip-1 in the cerebral spinal fluid can act as a biomarker for neuronal loss in the ERC, which is characteristic of Alzheimer’s disease. As well, this study suggests that cerebral spinal fluid measurements of Vilip-1 could be used as a direct indication for the amount of neuronal death in the ERC in early to moderate stages of Alzheimer’s disease. As a result, Vilip-1 levels might be able to be used in the future as a biomarker for Alzheimer’s disease, and to measure how much neuron loss has occurred in the early stages of the disease.
Source: Kirkwood, C.M., MacDonald, M.L., Schempf, T.A., Vatsavayi, A.V., Ikonomovic, M.D., Koppel, J.L., Ding, Y., Sun, M., Kofler, J.K., Lopez, O.L., Yates, N.A., Sweet, R.A. (2016). Altered Levels of Visinin-Like Protein 1 Correspond to Regional Neuronal Loss in Alzheimer Disease and Frontotemporal Lobar Degeneration. J Neuropathol Exp Neurol 75 (2): 175-182.
