MT3 and Alzheimer disease: It is proposed that the reduced MT-3 contribute to the loss of its protective effects and/or repair functions, leading to an exacerbation of the pathogenic processes, and the up-regulation of MT-1 and MT-2 may be a host defense response to elevated free intracellular Zn2+ levels, reflecting the pathology and inflammatory signals, and that all these changes imply a close relationship between MT and AD.