Effect of the inhaled anesthetics isoflurane, sevoflurane and desflurane on the neuropathogenesis of Alzheimer's disease

The incidence of Alzheimer's disease (AD) in individuals >65 years of age is 13% and similar to 66 million individuals in this age group undergo surgery annually under anesthesia. It is therefore important to determine whether commonly used inhaled anesthetics induce cytotoxicity, which may lead to neurodegeneration. Findings from several studies suggest that the anesthetics, isoflurane, sevoflurane and desflurane, may activate caspases, increase the synthesis and accumulation of -amyloid (A) protein, and induce hyperphosphorylation of tau proteins, all of which are cellular responses consistent with the neuropathogenesis of AD. Other studies have arrived at different and occasionally contradictory conclusions. The present review attempts to resolve this discrepancy by reviewing previous studies, which have investigated the effects of commonly used inhaled anesthetics on the synthesis and accumulation of A, tau pathology and cognitive function. The possible underlying mechanism was also reviewed. However, several aspects of this phenomenon remain to be elucidated. Further studies are required to fully examine anesthesia-induced neurotoxicity and elucidate the effect of inhaled anesthetics on the onset and progression of AD.