Abstract 193: First Demonstration that Hepatic Apob100 and Intestinal Apob48 Colocalize with Macrophages in Human Carotid Atherosclerotic Plaques

Abstract

Background: We previously demonstrated the presence and localization of hepatic apoB100 and intestinal apoB48 in human carotid atherosclerotic plaques by immunoperoxidase, immunofluorescence (IF), immunoelectron microscopy, and western blot; however, co-localization of apoB48 and apoB100 with macrophages has not been shown. Methods: In 3 patients undergoing carotid endarterectomy (CEA), plaques were stained for apoB100/CD68 and apoB48/CD68 dual stain (DS)-IF. CD68 was used to localize macrophages. Slides were processed for antigen retrieval and incubated with primary antibodies(ApoB100: ab50069-100 rabbit polyclonal antibody recognizing the C-terminal; apoB48:Shibayagi AKHB48E goat monoclonal antibody recognizing the C-terminal; CD68: Santa Cruz Biotechnologies SC-20060 mouse monoclonal antibody) and species-specific secondary antibodies (Invitrogen;A21447,A21235,A21244, or A11010 ).Confocal microscopy was used to visualize DS-IF. Results: There is intense CD68 staining throughout the plaques, demonstrating the presence of macrophages(B,E). As previously demonstrated, both apoB100 and apoB48 are present in plaques(A,D). Importantly, while CD68 staining is present throughout the plaque and in areas independent of apoB100 and apoB48, both apoB100 and apoB48 are always co-localized with CD68(C,F). Conclusions: This is the first demonstration that both hepatic apoB100 and intestinal apoB48 co-localize with macrophages in human carotid atherosclerotic plaques.