Cytokines in neuroinflammation and Alzheimer's disease.

Inflammation has been reported in numerous neurodegenerative disorders such as Parkinson's disease, stroke and Alzheimer's disease (AD). In AD, the inflammatory response is mainly located to the vicinity of amyloid plaques. Cytokines, such as Interleukin-1 (IL-1), Interleukin-6 (IL-6), Tumor Necrosis Factor alpha (TNF-alpha) and Transforminng Growth Factor beta (TGF-beta) have been clearly involved in this inflammatory process. Although their expression is induced by the presence of amyloid-beta peptide, these cytokines are also able to promote the accumulation of amyloid-beta peptide. Altogether, IL-1, IL-6, TNF-alpha and TGF-beta should be considered as key players of a vicious circle leading to the progression of the disease.