San Antonio Scientists Discover Pathway for Alzheimer’s Treatment

Researchers at the University of Texas at San Antonio have uncovered significant insights into the mechanisms of Alzheimer’s disease, potentially paving the way for new treatment approaches. The study, co-led by Juan Pablo Palavicini, an assistant professor in the Department of Cellular and Integrative Physiology, reveals that lipid abnormalities may play a crucial role in the disease’s progression, a focus that has been largely overlooked in previous research.

Alzheimer’s disease is characterized by the accumulation of amyloid plaques and twisted tau proteins in the brain, which disrupt normal cellular function. While much attention has been given to these proteins, Palavicini argues that lipids, which constitute more than half of the brain’s dry weight, deserve equal scrutiny. He stated, “They are largely ignoring the lipids, which, in my view, is a big mistake.”

Together with his colleague Xianlin Han and researchers from the University of California at Irvine, Palavicini’s team discovered that brain cells known as microglia are pivotal in managing lipid levels in the context of Alzheimer’s. Microglia serve as the brain’s immune cells, responsible for clearing away cellular debris. Under normal circumstances, they function like custodians, maintaining a clean environment for neurons.

As people age, microglia face an increasing burden of debris, which can overwhelm their capacity to function effectively. In Alzheimer’s patients, this overload can lead to microglial exhaustion, transitioning their role from beneficial to detrimental. “Instead of being the good guys that were helping us to clear the debris, they become bad guys and just start releasing inflammatory stimuli,” Palavicini explained.

One lipid of particular interest is Bis(monoacylglycero)phosphate, or BMP, which has been found to spike in Alzheimer’s conditions. The researchers hypothesize that this increase is an attempt by microglia to enhance their ability to clear the accumulating debris. In their study published in October 2023 in Nature Communications, they examined the impact of microglial activity on lipid behavior in both genetically modified mice and post-mortem brain samples from humans.

The findings indicated that when microglia were either deactivated or absent, levels of BMP did not rise in response to the presence of lipid debris or amyloid plaques. “When we depleted microglia, the levels came back completely to baseline,” Palavicini noted. This demonstrates that the increase in BMP observed in Alzheimer’s disease is indeed driven by microglial activity.

This unexpected discovery holds promise for future Alzheimer’s treatments. Current therapies primarily target amyloid plaques, which, by the time of diagnosis, have often already caused significant damage. “Even though you may clear the amyloid, it already caused a lot of trouble,” Palavicini explained, emphasizing the need for comprehensive approaches that address the resulting lipid debris.

As Alzheimer’s progresses, the breakdown of myelin—a protective sheath around neurons—can hinder communication between nerve cells. “If you start losing that myelin, then the neurons stop communicating well,” Palavicini said. This loss is exacerbated when microglia become overwhelmed, impairing their ability to repair myelin.

Palavicini’s research suggests that therapies aimed at supporting microglial function and enhancing debris clearance could slow cognitive decline in Alzheimer’s patients. “We need to find ways in which we can clear them better so that the brain can remyelinate,” he asserted. By bolstering the role of microglia, researchers might develop strategies that not only address amyloid plaques but also improve overall brain health in the context of aging and Alzheimer’s disease.

The collaborative efforts of Palavicini’s lab with institutions such as the University of California at Irvine mark a significant step forward in Alzheimer’s research. As scientists continue to explore the intricate interactions between lipids and microglial activity, new therapeutic pathways may soon emerge, offering hope to millions affected by this devastating disease.