MMP2 and Alzheimer disease: The hypothesis that a down-regulation of MMP-2 is a linking bridge between stress and AD pathology is supported by the evidence that i) MMP-2 expression was reduced in cortical neurons treated with corticosterone (Lee et al., 2009); ii) infusion of the MMP inhibitor, GM6001, increases Aβ formation in Tg2576 mice (Yin et al., 2006); and iii) MMP-2 was reduced in the parietal cortex of Tg2576 mice (Lee et al., 2009).