Philadelphia - The possibility that anesthesia and surgery produces lasting cognitive losses has gained attention over past decades, but direct evidence has remained ambiguous and controversial. Now, researchers at the Perelman School of Medicine at the University of Pennsylvania provide further evidence that Alzheimer's pathology may be increased in patients after surgery. The new research is published in the October 2011 issue of the journal Anesthesiology.

"We have long sought a clearer picture of the true impact of anesthesia and surgery on the central nervous system," said lead study author Roderic Eckenhoff, MD, Austin Lamont Professor of Anesthesia at Penn. "Although not definitive, this human biomarker study gives some credibility to the notion that anesthesia and surgery produce an inflammatory insult on the brain and accelerate chronic neurodegenerative diseases like Alzheimer's."

Clinical observation of postoperative cognitive dysfunction in patients and studies in animals have long suggested that anesthetics could interact with Alzheimer neuropathology, but the decades-long refractory period, when Alzheimer pathology is developing in the absence of detectable cognitive symptoms, has made research difficult.

With advances in diagnostic tests led by Penn Medicine's Leslie Shaw, PhD, professor of Pathology and Laboratory Medicine, there is now a validated biomarker test that is able to detect the presence of Alzheimer's disease (AD) biomarkers found in cerebral spinal fluid (CSF). This 'signature' combination of Alzheimer's disease indicators – amyloid beta and tau protein – can find disease markers before Alzheimer's symptoms appear and reliably predicts which patients will progress from mild cognitive impairment to full blown Alzheimer's disease. Generally speaking, highly increased CSF tau protein and decreased beta-amyloid are indicative of AD pathology.

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