A new study from Lund University in Sweden has found that the first changes in the brain of a person with Alzheimer’s can be observed as much as 10 years before the person is diagnosed with the disease.
The research group is led by Oskar Hansson, M.D., Ph.D. and is studying biomarkers — substances present in spinal fluid linked to Alzheimer’s disease.
The researchers in the current study studied about 140 people with mild memory impairment and found that a certain combination of markers, including low levels of beta-amyloid and high levels of the protein tau, indicate a high risk of developing Alzheimer’s in the future.
The researcher found that as many as 91 percent of patients with mild memory impairment who had these risk markers went on to develop Alzheimer’s within a 10-year period. In contrast, those who had memory impairment but normal values for the markers did not run a higher risk of getting Alzheimer’s than healthy individuals.
“This is a very important finding with regard to the development of new therapies against the disease,” Hansson said. “All prospective therapies have so far shown to be ineffective in stopping the disease, and many people are concerned that the pharmaceutical companies will give up their efforts in this field.
“But these failures may depend on the fact that the new therapies were initiated too late. When a patient receives a diagnosis today, the damage has already gone too far.”
Using biomarkers, pharmaceutical companies will be able to identify the people with mild symptoms who run the highest risk of developing Alzheimer’s within a 10-year period, the researcher notes. These patients can then be offered the opportunity to take part in trials for new medicines, while those who run a low risk of developing the disease do not need to be involved.
The 90 percent accuracy of the risk markers means that they are not sufficient as the only method for early diagnosis of Alzheimer’s, Hansson noted.
But if they can be combined with a clinical assessment and other diagnostic tools, such as imaging of the blood flow in the brain, it should be possible to increase the level of accuracy, he said.
However, this will only be relevant once drugs that are effective in slowing the disease have been developed, he added.
By observing how the levels of the biomarkers develop over the 10 years before the patient’s diagnosis, the researchers also were able to map the progression of the disease in the brain.
The results indicate that it starts with a modified turnover of beta-amyloid. Only later is this followed by changes in the tau protein and damage to nerve cells. This can be important information for those developing new therapies for Alzheimer’s, Hansson concluded.
The study has been published in the Archives of General Psychiatry.
Source: Lund University