Every year over 100 million people undergo surgery worldwide, most under general anesthesia with an inhaled drug. These drugs clearly affect cognitive ability at least in the short term, but the growing concern is that inhaled anesthetics may affect a person well beyond the perioperative period, even permanently. Several factors appear to play a role in this subtle loss of cognitive ability, most notably age.
A specific effect of these drugs on dementias like Alzheimer's disease, though suspected for many years, has only been recently supported by data. In 2003, Eckenhoff's group showed that the inhaled anesthetics enhance the aggregation and cytotoxicity of the amyloid beta peptide. Just last month, a study reported that these drugs also enhance the production of amyloid beta in isolated cells. But these protein and cell culture studies are a long way from showing that an effect occurs in vivo. This new study provides the first evidence that the predicted effect occurs in animals.