Astrocytes Found to Influence Progression of Alzheimer’s Disease, Challenging Previous Beliefs
According to groundbreaking research conducted by the University of Pittsburgh School of Medicine, star-shaped brain cells known as astrocytes play a crucial role in the progression of Alzheimer’s disease. This finding challenges the long-held belief that the accumulation of amyloid plaques alone triggers the development of Alzheimer’s.
For many years, scientists have been puzzled by the fact that some individuals with toxic amyloid accumulations in the brain do not exhibit dementia symptoms associated with Alzheimer’s disease. The study conducted by the University of Pittsburgh School of Medicine may have finally provided an answer to this perplexing question.
By testing the blood of over 1,000 cognitively unimpaired elderly individuals with and without amyloid pathology, the research team found that only those who had a combination of amyloid burden and blood markers indicating abnormal astrocyte activation would progress to symptomatic Alzheimer’s in the future. This discovery is crucial for the development of drugs aimed at halting the progression of the disease.
Senior author Tharick Pascoal, M.D., Ph.D., associate professor of psychiatry and neurology at Pitt, stated, “Our study argues that testing for the presence of brain amyloid along with blood biomarkers of astrocyte reactivity is the optimal screening to identify patients who are most at risk for progressing to Alzheimer’s disease. This puts astrocytes at the center as key regulators of disease progression, challenging the notion that amyloid is enough to trigger Alzheimer’s disease.”
Alzheimer’s disease is a neurodegenerative condition characterized by progressive memory loss and dementia. The accumulation of amyloid plaques and tau tangles in the brain has long been considered the primary cause of the disease. However, recent research suggests that other factors, such as heightened brain inflammation, may also play a significant role in the progression of Alzheimer’s.
Previous research by Pascoal and his group showed that brain tissue inflammation triggers the spread of pathologically misfolded proteins and eventually leads to cognitive impairment in Alzheimer’s patients. Now, their latest study reveals that cognitive impairment can be predicted through a blood test.
Astrocytes are specialized brain cells that support neuronal cells by supplying them with nutrients and oxygen. Until now, their role in health and disease had been overlooked. However, the research from the University of Pittsburgh School of Medicine indicates that astrocytes play a crucial role in coordinating the relationship between amyloid and tau, like a conductor directing an orchestra.
The findings of this study have direct implications for future clinical trials of Alzheimer’s drug candidates. With trials moving to earlier stages of pre-symptomatic disease, it is crucial to correctly diagnose the risk of developing Alzheimer’s. The inclusion of astrocyte reactivity markers in diagnostic tests will improve the selection of patients who are likely to progress to later stages of the disease, allowing for more targeted therapeutic interventions.
The research was funded by the National Institute on Aging and the Alzheimer’s Association. The study was published in the journal Nature Medicine.