Inflammation: a bridge between postoperative cognitive dysfunction and Alzheimer's disease.

Postoperative cognitive dysfunction (POCD) which is a decline in cognitive function after surgery can present days to weeks after surgery and may remain a permanent disorder. The exact pathophysiological mechanism of POCD is still unknown. In view the incidence of POCD does not seem to be influenced by the depth and the type of anesthesia, many investigators believe that inflammatory response plays a key role in the pathogenesis of POCD. Animals and human studies show POCD associates with peripheral inflammatory and neuroinflammatory response. Alzheimer's disease (AD) is a insidious and progressive neurodegenerative disorder of the elderly. In clinical practice AD trials have not provided a satisfactory approach for the prevention and therapy. It is because we still do not know its exact etiological factor and pathogenesis. Similarly, neuroinflammatory response is involved in the pathophysiological process of AD. The activation of microglia may be the common pathogenesis of POCD and AD. We hypothesize that inflammatory response is the initial factor of the occurrence and development of POCD and AD. Neuroinflammatory response associates with POCD and AD. The effective pathway to prevention and therapy of POCD and AD should consider measures against inflammatory response, especially against neuroinflammatory response. (c) 2009 Elsevier Ltd. All rights reserved.