Schematic to show biomarker identification in Down syndrome patients that link to Alzheimer’s disease. Image provided by Tiziana Cabras.
In a paper just out in Molecular & Cellular Proteomics, researchers report to have identified molecules in the saliva from people with Down syndrome that differ from those in healthy people. The tantalizing thing is that some of the identified molecules are thought to play roles in Alzheimer’s disease. As I briefly note in my latest cover story in ASBMB Today, Down syndrome patients can be particularly susceptible to Alzheimer’s disease.
Saliva contains biomarkers that act as early indicators for various conditions. The appealing thing about saliva is that it’s easy to collect — just spit into a tube and you’re done.
Because of saliva’s importance as a diagnostic fluid, a team led by Tiziana Cabras at the University of Cagliari in Italy wanted to see if it could find differences in biomarkers in those with Down syndrome. The investigators used a method called top-down proteomics to analyze all the salivary proteins in samples taken from 36 Down syndrome people. They then compared the salivary proteomes to those of sex- and age-matched control groups
Most intriguingly, Cabras and colleagues found that the levels of three proteins involved in immune responses, S100A7, S100A8 and S100A12, were increased significantly in the saliva of those with Down syndrome. The increase “may be of particular interest as biomarkers of the early onset Alzheimer’s disease, which is frequently associated with Down syndrome,” says Cabras. S100A7 has been previously shown to be a possible biomarker for Alzheimer’s disease.
Given this tantalizing, preliminary observation, Cabras says the researchers will recruit more patients to their study to see if the observation holds out. They also want to check to see if the same proteins also are increased in the saliva of Alzheimer’s disease patients and those with other neurological diseases. This would confirm that these proteins can act as salivary biomarkers to track the onset and progression of such diseases.
