Indeed, a highly significant ( p < 0.0001) diagnosis × location interaction (i.e., the closer to ThioS+ plaques from AD donors the higher the MAO-B area fraction versus no change in MAO-B area fraction with distance to sham plaques in CTRL donors) supports this interpretation.
A multivariate regression analysis with MAO-B area fraction as outcome variable, Aβ+ area fraction, number of pTau+ neurofibrillary tangles, GFAP+ reactive astrocytes, and CD68+ reactive microglia, and cortical thickness as independent variables, and adjusted by age at death, confirmed that MAO-B expression level is independently associated with cortical thickness and number of CD68+ reactive microglia and showed a trend ( p = 0.0546) toward a positive independent association with the number of GFAP+ reactive astrocytes, but no significant association with either total Aβ plaque burden or the number of neurofibrillary tangles (Table 6 ).
Lastly, we found a marginally significant ( p = 0.0590) increase in GFAP+ area fraction and a significant increase in CD68+ area fraction in high ADNC burden versus not AD/low ADNC burden donors, with intermediate ADNC burden donors exhibiting intermediate levels of reactive gliosis.