People with dementia often exhibit a ‘dropping off’ of cognitive abilities after surgery. In fact, caregivers of people with dementia sometimes identify surgery as the point in time where cognitive problems initially began. But the exact cause of the post-surgical cognitive decline is not fully understood. Multiple factors may be at play, including anesthesia, inflammation and oxygen levels.
Past research suggests that Alzheimer’s pathology might be increased in patients after surgery and anesthesia, but did not provide insights into exactly what was behind the increase. New research from the University of Pennsylvania, using mouse models of Alzheimer’s disease, indicates that inflammation, not anesthesia, may be the culprit.
Using mice with human Alzheimer’s disease genes but no outward symptoms of Alzheimer’s, a team of researchers led by Roderic Eckenhoff, MD, exposed the mice to anesthesia alone or anesthesia and surgery. They found that surgery caused a lasting increase of Alzheimer’s pathology due to brain inflammation. Compared to mice that were exposed to anesthesia alone, those that had surgery showed significant cognitive impairment that persisted for at least 14 weeks after surgery. Mice without the Alzheimer’s gene had neither changes in the brain nor cognitive impairment.
As this Alzheimer’s mouse model more closely represents the familial form of Alzheimer’s disease, which causes a small minority of Alzheimer’s cases, it is not clear whether the results of this study would represent the majority of people who develop late-onset ‘sporadic’ Alzheimer’s disease.