Activated microglia, protein oxidation, accumulation of protein material and an increase in inflammatory processes and decreased proteolysis are all parameters found in neurodegeneration. This evidence suggests an important connection between protein oxidation, proteolytic processes and microglial activation. Activated microglial cells not only further damage extracellular proteins and increase the oxidative burden to the brain, but also change their ability to degrade oxidized and AGE-modified proteins.

The role of microglial cell in the brain, the effects of their activation and the intracellular changes in these cells related to the expression of uptake and proteolytic mechanisms and to the degradation efficiency of various materials is reviewed in this chapter.