A large study led by Lund University in Sweden has shown that people with Alzheimer’s disease can now be identified before they experience any symptoms. It is now also possible to predict who will deteriorate in the coming years. The study is published in Nature Medicine and is very timely in light of the recent development of new drugs for Alzheimer’s disease.
It has long been known that there are two proteins related to Alzheimer’s: beta-amyloid, which forms plaques in the brain, and tau, which at a later stage accumulates inside brain cells. Elevated levels of these proteins in combination with cognitive impairment have previously been the basis for diagnosing Alzheimer’s.
“Changes occur in the brain ten to twenty years before the patient experiences any clear symptoms, and it is only when tau begins to spread that nerve cells die and the person in question experiences the first cognitive problems. This is why Alzheimer’s is so difficult to diagnose in its early stages,” explains Oskar Hansson, senior physician in neurology at Skåne University Hospital and professor at Lund University.
He has now led a large international research study that was conducted with 1,325 participants from Sweden, the US, the Netherlands and Australia. Participants had no cognitive impairment at the start of the study. By using PET scans, the presence of tau and amyloid in the brains of the participants could be visualized. They found that people in whom both proteins were discovered had a 20- to 40-fold greater risk of developing the disease at follow-up a few years later, compared to participants who had no biological changes.
“When both beta-amyloid and tau are present in the brain, it can no longer be considered a risk factor, but rather a diagnosis. A pathologist examining brain samples like this would immediately diagnose the patient with Alzheimer’s,” he says . Rik Ossenkoppele, who is the first author of the study and is a senior researcher at Lund University and the University Medical Center Amsterdam.
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 decline begins. There’s also the group to which he and his colleagues belong, who say a diagnosis can be based solely on biology and what can be seen in the brain.
“You can, for example, compare our results with prostate cancer. If you do a biopsy and find cancer cells, the diagnosis will be cancer, even if the person in question has not yet developed symptoms,” says Rik Ossenkoppele.
Recently, positive results have appeared in clinical trials of a new Alzheimer’s drug, Lecanemab, which has been evaluated in Alzheimer’s patients. Based on this, the Lund University study is particularly interesting, say the researchers:
“If we can diagnose the disease before the cognitive challenges appear, we may be able to use the drug to slow down the disease at a very early stage. In combination with physical activity and good nutrition, we would have a better chance of preventing or slowing down the disease. future cognitive impairment. However, more research is needed before a treatment can be recommended for people who have not yet developed memory loss,” concludes Oskar Hansson.
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