People with Alzheimer's disease can be identified before symptoms appear

People with Alzheimer's disease can be identified before symptoms appear

A large study led by Lund University in Sweden has shown that people with Alzheimer's disease can now be identified before they show any symptoms. It is now possible to predict who will deteriorate in the next few years. The study was published in Nature Medicine and is very timely given the recent development of new drugs for Alzheimer's disease.

It has long been known that there are two proteins linked to Alzheimer's - beta-amyloid, which forms plaques in the brain, and tau, which accumulates in brain cells at a later stage. Elevated levels of these proteins combined with cognitive impairment previously formed the basis for diagnosing Alzheimer's disease.

Between ten and twenty years, before the patient experiences clear symptoms, changes occur in the brain, and only when dew spreads do the nerve cells die and the person affected begins to have cognitive problems. That’s why early-stage Alzheimer’s is so difficult to diagnose.”

Oskar Hansson, senior physician in neurology at Skåne University Hospital and professor at Lund University

He has now led a large international research study conducted with 1,325 participants from Sweden, the USA, the Netherlands and Australia. The participants had no cognitive impairment at the start of the study. PET scans were used to visualize the presence of tau and amyloid in the participants' brains. It was found that the people in whom the two proteins were detected were 20 to 40 times more likely to develop the disease at follow-up a few years later, compared to participants who had no biological changes.

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"If both beta-amyloid and tau are present in the brain, this can no longer be considered a risk factor but rather a diagnosis. A pathologist examining samples from such a brain would immediately diagnose the patient with Alzheimer's," says Rik Ossenkoppele, first author of the study and senior researcher at Lund University and the University of Amsterdam Medical Center.

He explains that Alzheimer's researchers belong to two schools of thought - on the one hand, those who believe that Alzheimer's disease cannot be diagnosed until cognitive impairment begins. There's also the group that he and his colleagues belong to - who say that a diagnosis can be based purely on biology and what you see in the brain.

"You can compare our results with prostate cancer, for example. If you find cancer cells in a biopsy, the diagnosis is cancer, even if the person in question has not yet developed any symptoms," says Rik Ossenkoppele.

Recently, positive results were reported in clinical trials of a new Alzheimer's disease drug, lecanemab, which was studied in Alzheimer's patients. On this basis, the Lund University study is particularly interesting, say the researchers:

"If we can diagnose the disease before cognitive challenges occur, we may be able to use the drug to slow the disease at a very early stage. Combined with physical activity and good nutrition, we would then have a greater chance of prevention." or slow future cognitive impairment. However, further research is needed before treatment can be recommended for people who have not yet developed memory loss,” concludes Oskar Hansson.

Source:

Lund University

Reference:

Ossenkoppele, R., et al. (2022) Amyloid and tau PET-positive cognitively unimpaired individuals are at high risk for future cognitive decline. Naturopathy. doi.org/10.1038/s41591-022-02049-x.

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