Why Anesthesia Is Associated With Cognitive Impairment And Risk Of Alzheimer's Disease

Anesthesia has previously been found to be associated with cognitive impairment and the risk for AD. This study helps elucidate the molecular mechanisms underlying these associations.

The researchers found that in test animals, anesthesia for short periods (30 seconds to 5 minutes) induced tau phosphorylation at some selective phosphorylation sites to a small but significant extent. Anesthesia for a longer time (1 hour) induced much more dramatic phosphorylation at the same sites, possibly as a result of anesthesia-induced hypothermia. The observation that anesthesia did not induce global hyperphosphorylation of brain proteins, but instead specific hyperphosphorylation of tau protein at the AD-related abnormal hyperphosphorylation sites suggests that tau hyperphosphorylation might be the mechanism that links anesthesia and the risk of cognitive impairment and/or AD.

AD is the most common cause of dementia in adults and affects approximately 27 million individuals worldwide and over four million in the United States alone. Most AD cases are sporadic and are believed to be caused by multiple factors. Understanding the mechanism by which anesthesia may increase the risk for cognitive impairment will help in the design of strategies for preventing and treating dementia and AD. “This is a very important finding related to Alzheimer’s disease,” said OMRDD Commissioner Diana Jones Ritter. “I am pleased that these findings will lead to helping people live richer lives through the research findings.”

The study was carried out by the Brain Metabolism Laboratory at IBR. Headed by Dr. Cheng-Xin Gong, the laboratory is focusing its research on the roles of several signaling and metabolic factors in neurodegeneration and deregulated neurodevelopment, especially related to AD and autism.