Blood test for protein could identify early stages of Alzheimer’s disease

Surjit kumar Dhal, Bhubaneswar, Jan 23: A simple blood test may soon detect Alzheimer’s years in advance.

        This was what an international group of scientists concluded after evaluating the simple test that used blood samples from people with a rare form of Alzheimer’s disease that they had inherited, health magazine Medical News Today reported on Wednesday.

The team included researchers from Washington University School of Medicine in St. Louis, MO and the German Center for Neurodegenerative Diseases in Tübingen, Germany.

The test looks for changes in levels of the neurofilament light chain (NfL) protein. The protein normally resides inside brain cells, or neurons, as part of their internal skeleton.

However, damaged and dying cells can leak NfL into surrounding cerebrospinal fluid. The protein then travels from the fluid into the bloodstream.

Others have already shown that raised levels of NfL in cerebrospinal fluid is a strong sign that some brain damage has occurred. Doctors can test for the protein using a lumbar puncture, or spinal tap, but many people are reluctant to undergo the procedure.

Now, in a Nature Medicine paper about the recent study, the authors report how they demonstrated that NfL levels in spinal fluid correlated with levels in blood and “are elevated at the presymptomatic stages of familial Alzheimer’s disease.”

“This could be,” says co-first study author Stephanie A. Schultz, who is a graduate student at Washington University, “a good preclinical biomarker to identify those who will go on to develop clinical symptoms.”

The researchers suggest that the quick and inexpensive method could one day also test for other conditions involving brain damage, such as traumatic brain injury, multiple sclerosis, and stroke.

Alzheimer’s disease is a major cause of dementia that destroys brain cells and tissue. As the brain damage spreads, it leads to symptoms such as confusion, memory loss, and diminishing capacity to function. Eventually, the person can no longer lead an independent life.

Estimates from the National Institute on Aging suggest that there could be at least 5.5 million people with Alzheimer’s in the United States.

Leaky blood vessels in the brain could have a role in Alzheimer’s disease that is separate from the buildup of toxic protein.

Postmortem exams of the brains of people with Alzheimer’s disease reveal three typical hallmarks: plaques of beta-amyloid protein, tangles of tau protein, and loss of connections between brain cells.

Alzheimer’s disease mostly strikes people aged 65 years and older, but there are rarer forms that can strike earlier.

Scientists do not fully understand the causes of Alzheimer’s disease, especially the forms that strike people later in life. They suggest that these forms likely arise from a complex interplay of genes, environment, and lifestyle.

Around 1 in 20 people who develop Alzheimer’s disease will have an early-onset form that begins to show symptoms before the age of 65 years.

The most common cause of these early-onset forms of Alzheimer’s disease is gene mutations that parents pass on to their offspring.