BLOOD TEST PREDICTS ALZHEIMER’S DISEASE 10 YEARS BEFORE SYMPTOMS APPEAR

The presence of a substance released by brain cells could be an early warning sign for the condition

The presence of a specific biomarker in the blood may be an early indicator of Alzheimer’s disease, researchers from Sweden’s Karolinska Institutet have found. The discovery could lead to earlier diagnosis of the condition via blood tests, and increase the chance of slowing down its progression.

Alzheimer’s disease is responsible for around 60 to 70 per cent of all dementia cases. It is caused by beta-amyloid and tau proteins building up in the brain and damaging nerve cells. These build-ups can begin up to 25 years before they lead to noticeable symptoms such as memory loss and issues with speech.

The team analysed blood plasma samples from 75 patients, 33 that carried a genetic mutation that predisposes them to develop a rare inherited form of Alzheimer’s and 42 without the mutation.

They found that an increase in glial fibrillary acidic protein (GFAP) in the blood was a potential early warning sign for those that went on to develop Alzheimer’s. GFAP is produced by cells called astrocytes in the brain and spinal cord. The levels of GFAP was seen to increase around 10 years before the emergence of the first symptoms.

“Our results suggest that GFAP, a presumed biomarker for activated immune cells in the brain, reflects changes in the brain due to Alzheimer’s disease that occur before the accumulation of tau protein and measurable neuronal damage,” said lead researcher Charlotte Johansson, doctoral student at the department of neurobiology, care sciences and society, Karolinska Institutet, Sweden. “In the future it could be used as a non-invasive biomarker for the early activation of immune cells such as astrocytes in the central nervous system, which can be valuable to the development of new drugs and to the diagnostics of cognitive diseases.”