Oxidative Stress and Metabolic Syndrome: Cause or Consequence of Alzheimer's Disease?

Alzheimer's disease (AD) is a major neurodegenerative disease affecting the elderly. Clinically, it is characterized by a progressive loss of memory and cognitive function. Neuropathologically, it is characterized by the presence of extracellular beta-amyloid (A beta) deposited as neuritic plaques (NP) and neurofibrillary tangles (NFT) made of abnormal and hyperphosphorylated tau protein. These lesions are capable of generating the neuronal damage that leads to cell death and cognitive failure through the generation of reactive oxygen species (ROS). Evidence indicates the critical role of A beta metabolism in prompting the oxidative stress observed in AD patients. However, it has also been proposed that oxidative damage precedes the onset of clinical and pathological AD symptoms, including amyloid-beta deposition, neurofibrillary tangle formation, vascular malfunction, metabolic syndrome, and cognitive decline. This paper provides a brief description of the three main proteins associated with the development of the disease (A beta, tau, and ApoE) and describes their role in the generation of oxidative stress. Finally, we describe the mitochondrial alterations that are generated by A beta and examine the relationship of vascular damage which is a potential prognostic tool of metabolic syndrome. In addition, new therapeutic approaches targeting ROS sources and metabolic support were reported.