with a blood test it can be anticipated if an elderly person will develop the disease

This Monday, science took another important step in its fight to detect Alzheimer’s disease on time and respond to one of the greatest concerns that the medical community in the world has studied about this disease: why do many individuals with flooded brains of toxic amyloid aggregates —a biomarker of this disease— never develop dementia associated with this pathology?

Well, a group of scientists from the University of Pittsburgh School of Medicine assure through an article published in the journal Nature Medicinehave an answer: There are star-shaped brain cells in the brain, called astrocytes, which determine whether or not a person develops the disease.

The result of this research was possible after analyzing the blood of more than a thousand elderly people without cognitive deterioration, with and without amyloid pathology. In this way, the scientists discovered that only those with a combination of amyloid burden and blood markers of abnormal astrocyte activation would develop Alzheimer’s. This is a discovery of great importance for the development of drugs to stop the progression.

“Our study argues that analysis of the presence of brain amyloid in conjunction with blood biomarkers of astrocyte reactivity is the optimal screening method to identify patients at increased risk of progressing to Alzheimer’s disease,” says Tharick Pascoal, Associate Professor of Psychiatry and Neurology at Pitt.

“That is, astrocytes are key regulators of disease progression. Amyloid alone is not enough to trigger Alzheimer’s disease, ”she stresses.

It is believed that throughout the world there 46.8 million people living with Alzheimer’s disease or other dementias. By 2030, if there are no new discoveries, we will see an increase, reaching almost 74.7 million. By 2050, the rates could exceed 131.5 million.

Alzheimer’s is a neurodegenerative disorder that causes progressive memory loss and dementia, significantly reducing quality of life.

It is a disease characterized by the accumulation of amyloid plaques (protein aggregates that lodge between nerve cells in the brain) and groups of disordered protein fibers, called tau tangles, that form inside neurons.

For decades, neuroscientists have believed that the buildup of amyloid plaques and tau tangles is not only a sign of Alzheimer’s disease, but also its cause, which is why existing drugs have targeted amyloid and tau and ignored others. brain processes.

But recent findings from groups like Pascoal’s suggest that some alterations in the brain, such as increased brain inflammation, could be just as important as amyloid burden.

The direct cause of deterioration

Two years ago, Pascoal and his group discovered that inflammation of brain tissue triggers the spread of pathologically misfolded proteins in the brain and is a direct cause of eventual cognitive decline in patients with Alzheimer’s disease.

Now this team has discovered that cognitive decline can be predicted by a blood test.

Astrocytes are cells in brain tissue that supply neurons with oxygen and nourishment and protect them from pathogens. But, because they do not conduct electricity and did not appear to play a direct role in communication between neurons, their role in disease had been overlooked.

The team analyzed several blood samples from a group of participants in three independent studies of older adults without cognitive impairment for biomarkers of astrocyte reactivity—a glial fibrillary acidic protein, or GFAP—along with the presence of pathological tau.

The study demonstrated that only those who were positive for both amyloid and astrocytic reactivity showed evidence of progressive development of tau pathology, indicating a predisposition to clinical symptoms of Alzheimer’s disease.

The results have direct implications for future clinical trials of Alzheimer’s drug candidates.

The inclusion of other markers in diagnostic tests will improve the selection of patients likely to progress to later stages of Alzheimer’s and will help refine the selection of candidates for therapeutic interventions most likely to benefit.