In an advance toward a much-needed early diagnostic test for Alzheimer's disease (AD), scientists have discovered that older women destined to develop AD have high blood levels of a protein linked to pregnancy years before showing symptoms. Their report appears in ACS' Journal of Proteome Research.
Theo Luider and colleagues explain that more than 26 million people worldwide already have AD, and the numbers are rising with the graying of the population. Doctors can prescribe any of several drugs to slow the disease's advance. But it is important to start treatment as early as possible. Unfortunately, however, no test exists to diagnose patients before obvious memory loss and other symptoms appear. Luider's team decided to look for proteins in the blood that might be used in such a test.
They looked for those proteins in blood samples of 86 people aged 60-90 who participated in a larger study of aged-related brain changes conducted in The Netherlands. Surprisingly, Luider's group found that significant elevations in pregnancy zone protein (PZP) occurred in women an average of 4 years before diagnosis of AD. Scientists long have known that PZP levels rise during pregnancy, but this was the first link with AD. Luider further discovered the apparent source of the PZP in the brain of these women, who were not pregnant: PZP was being produced in senile plaques, degenerated areas of the brain associated with AD.