Changes in the brain indicate Alzheimer’s
At present, there is no cure for Alzheimer’s disease. Researchers in Turku have mapped out the mechanics of the early stages of the disease.
Alzheimer’s disease is a progressive disease which damages memory and information processing. Approximately 80,000 people have been diagnosed with Alzheimer’s disease in Finland, and the number is growing due to the aging of the population. Consequently, the search for new treatments is more important than ever.
- We have found that people suffering from Alzheimer’s disease exhibit amyloid protein deposition in their brain. The exact role of the amyloid deposits is still unclear, but they may be an early development of the disease, says MD Noora Scheinin whose research concentrates on Alzheimer’s disease.
A new research method
In her research, Scheinin used PET imaging and tracer 11C-PIB which sticks to the amyloid deposits. This amyloid tracer is used in specialised research centres around the world. Testing whether the method can be used for early detection of the disease formed a part of her dissertation.
- Only a handful of researchers in Finland are working on this particular topic because we only have one PET centre.
The method is already in clinical use to some extent. Imaging can confirm diagnoses in cases where the symptoms point to Alzheimer’s disease but other methods fail to yield a certain result.
- However, imaging is not routinely used in diagnosis, Scheinin says.
Scheinin studied 17 pairs of twins, both identical and unidentical. One twin in a pair suffered from Alzheimer’s type cognitive impairment, while the other twin’s memory functions were normal. There was also a control group of nine healthy individuals.
- My research showed an increase in the number of amyloid deposits in the twin suffering from Alzheimer’s. In addition, the identical twin who did not exhibit any symptoms had more amyloid deposition than the other healthy subjects.
The results indicate that genotype affects the formation of the deposits. The study also supports the view that amyloid protein accumulation is an early development of the disease, since amyloid deposits may be found in a person who does not exhibit any other signs of Alzheimer’s disease.
In addition, Scheinin screened the formation of amyloid deposits in Alzheimer’s patients for a few years without seeing an increase. This also indicates that the deposits form before any other signs of the disease.
Noora Scheinin
Hard to predict
It is impossible to give a certain prognosis even if amyloid deposits are found. The patient is at a heightened risk compared to people who do not exhibit amyloid deposition, but there may be decades between the formation of the deposits and the onset of the disease. Furthermore, individuals with amyloid deposition do not necessarily contract the disease due to other, protective factors. Research on these factors is still ongoing.
- A negative predictive value is a good sign: if no amyloid deposits are found in the patient, the onset of Alzheimer’s disease is unlikely, at least for the following couple of years. Furthermore, patients with amyloid deposition do not always contract the disease.
Noora Scheinin wrote her dissertation on the "Early Detection of Alzheimer's Disease Beta-amyloid Pathology - Applicability of Positron Emission Tomography with the Amyloid Radioligand 11C-PIB".
Text: Joni Tauriainen
Photos: Daniela Hartmann & Noora Scheinin
Translation: Suvi Kauppila