We compared the effects of three pretreatment immunohistochemical techniques (no pretreatment, pepsin predigestion and heat pretreatment (HEAT)) for detecting intracellular β-amyloid42 (Aβ42) in pyramidal neurons of formalin-fixed Alzheimer's disease (AD) cortices (n=25). Although all three protocols immunostained Aβ42 in amyloid plaques using four commercially-obtained Aβ42 specific antibodies, only the HEAT protocol consistently detected prominent intracellular Aβ42 in pyramidal neurons. This suggests that the Aβ42 present in amyloid plaques may be structurally distinct from that located within the neurons perhaps due to differential binding proteins coupling or a consequence of formalin fixation. Detection of an abundant intracellular Aβ42 in neurons may provide alternate explanations for the origin of dense-core amyloid plaques in AD cortices other than the conventional chronic extracellular Aβ42 deposition hypothesis.
All Science Journal Classification (ASJC) codes