Vacutainer blood bottles.
(photo credit: Wikimedia Commons)
A biological blood marker linked to Alzheimer’s disease that could eventually serve as a reliable diagnostic blood test for the progressive, fatal dementia has been identified by researchers at Tel Aviv University, Rambam Medical Center/the Techion-Israel Institute of Technology and Harvard University.
“We hope that in the future, it will be possible to use our discovery to develop a simple blood test for this serious disease even in its early stages,” said TAU lead researcher Prof. Illana Gozes.
Today, diagnosing Alzheimer’s is a long and complicated process, and most doctors use subjective memory tests of cognitive and functional abilities and behavior changes, she said on Tuesday. In special cases, expensive brain scans are carried out that are not yet available in Israel.
Sometimes, invasive tests of the brain and spinal fluids are conducted, noted Gozes of the department of human molecular genetics and biochemistry at TAU ’s Sackler Faculty of Medicine and of the Sagol School of Neuroscieces.
The new discovery, just published in the Journal of Alzheimer’s Disease may lead to a significant breakthrough in diagnosing Alzheimer’s, she said. The presence of a certain amount of the biological marker in the blood characterizes the dementia patients. The research focused on a protein named ADNP that was discovered in Gozes’s lab 15 years ago. “In previous studies, we showed that the protein and its derivatives protect the brain from various diseases, In the present study, we decided to first examine whether there is a link between ADNP expression in the patient’s blood and cognitive abilities.”
In the first of three parts, a group of 40 educated and healthy older adults in Boston were tested for their IQ, and blood samples from them were sent to TAU ’s lab.
Surprisingly, the higher the participants’ IQ, the higher the level of ADNP in their blood. In the second stage, also in Boston, the same 40 volunteers underwent scanning of amyloid plaque in their brains. This is the protein that accumulates in the brains of Alzheimer’s patients, said Gozes, but sometimes, it is also found in smaller amounts in the brains of healthy people.
“We sought to compare the amount of amyloid in the brain and the expression of ADNP in their blood,” she continued. This was carried out by TAU researchers, who found a connection between the two. The higher the amount of amyloid in the brain, the lower the amount of RNA genetic material associated with ADNP.
The two experiments on older but healthy people found a link between ADNP levels and its expression in the blood and their cognitive abilities. Thus, the better their cognitive abilities, the higher the ADNP level in the blood, Gozes said.
The third experiment at Rambam tested 17 people suffering from the dementia and compared them with 11 healthy people with normal cognition and 15 with mild cognitive impairment. The researchers had a big surprise: In the white blood cells of Alzheimer’s patients, “we found eight times as much RNA expressing ADNP compared to the others. There is no doubt that this is a clear biological marker of Alzheimer’s that could serve as the basis for a simple blood test to diagnose it. Such a test could make it possible for patients who come out positive to get preventive treatment that delays and moderates the disease.”
As the study was small, on relatively few participants, “one can’t reach sweeping conclusions. We now intend to expand the experiments on additional populations,” Gozes concluded.