Diagnostic dream: Researchers developing blood test for Alzheimer’s

Imagine being able to diagnose diseases such as Alzheimer’s, Parkinson’s, multiple sclerosis and early stage breast cancer by analyzing one drop of blood.

That’s the long-term goal of researchers at Rowan University School of Osteopathic Medicine (RowanSOM) in Stratford, New Jersey, who are currently working to develop a blood test for Alzheimer’s disease. The idea, says RowanSOM cell biology professor Robert Nagele, PhD, is to detect Alzheimer’s in its early stages, when patients are not yet exhibiting symptoms.

Analyzing biomarkers to detect disease

The blood test works by examining the makeup of the nearly 2,000 autoantibodies found in each person’s blood. Dr. Nagele’s team believes autoantibodies serve to clear the debris that’s constantly being generated by the body.

Diseased organs create extra debris, leading to the deployment of more autoantibodies. Thus, analyzing a person’s autoantibody makeup can help identify the presence of illness.

To analyze blood samples, the researchers used a protein microarray with more than 9,000 human protein targets, which acted as bait to attract autoantibodies.

The microarray can hold up to 20,000 protein targets and only 20 to 50 autoantibodies are needed to conduct each diagnostic, Dr. Nagele pointed out, so one blood test could potentially screen for hundreds of different conditions at once.

Promising accuracy

Based on analysis of autoantibody data, the researchers identified 10 biomarkers that can differentiate patients with Alzheimer’s disease from patients who don’t have dementia with 96% accuracy.

The test was also 93% accurate in identifying patients with Parkinson’s.

Ultimately, Dr. Nagele said, the blood test could be used not only for early detection of disease, but also to evaluate how effectively treatment is working.

How the blood-brain barrier protects against Alzheimer’s

The cause of Alzheimer’s is unknown, but one key element of the disease is the presence of amyloid plaques in the brain. Dr. Nagele likened these amyloids to graves marking the spot where a neuron used to be and said their accumulation seems to be related to leaks in the brain-blood barrier.

“In a healthy brain, everything stays in the blood vessel—it’s like Vegas,” Dr. Nagele explained. “I’ve worked with over one hundred brains with Alzheimer’s, and in every one, the blood-brain barrier had been breached.”

Breakdowns in the blood-brain barrier are caused by vascular issues like diabetes, hypertension, vascular inflammation and plaque in the arteries, Dr. Nagele said, which highlights the importance of diet and exercise in maintaining health.

For some geriatric patients, anesthesia can also lead to severe short-term damage to the blood-brain barrier. Dr. Nagele believes this damage is probably what triggers post-operative delirium, a condition marked by sudden cognitive changes after surgery.