Delirium causes confusion and behavior changes, affects millions of patients each year and can increase a patient’s risk of long-term neurological problems. It is common in hospitalized patients who are placed on ventilators to assist their breathing.

“Microglia, the resident immune cells in the brain, can be destructive to brain cells in some neurological diseases, but also can be protective,” said Shouri Lahiri, MD, director of the Neuroscience Critical Care Unit and director of Neurocritical Care Research in the Department of Neurology at Cedars-Sinai and senior author of the study. “While previous research has suggested that the action of microglia may cause or worsen delirium, we found that the opposite is true. When we depleted levels of microglia in laboratory animal experiments, delirium-associated brain changes and behaviors increased. And when we restored microglia levels to normal, the changes were almost completely reversed.”

Medications that activate neuron-protecting microglia could be one option for managing delirium. Investigators previously determined that a protein called interleukin-6 damages neurons, and future studies could clarify whether it or other proteins activate neuron-protecting microglia. Future research is also planned to help determine the conditions under which microglia can cause damage to neurons, said Lahiri, an associate professor in the departments of Neurology, Neurosurgery, and Biomedical Sciences.

First authors: Landon Scott, Kevin D. Winzey

Additional authors: Debbie Moreira, Catherine Bresee, Jean‐Philippe Vit, Warren G. Tourtellotte, S. Ananth Karumanchi, and Shouri Lahiri

Funding: F. Widjaja Foundation

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