Development of a smart nano-vehicle to target cerebrovascular amyloid deposits and brain parenchymal plaques observed in Alzheimer's disease and cerebral amyloid angiopathy

Purpose. To design a smart nano-vehicle (SNV) capable of permeating the blood-brain barrier (BBB) to target cerebrovascular amyloid formed in both Alzheimer's disease (AD) and cerebrovascular amyloid angiopathy (CAA). Methods. SNV consists of a chitosan polymeric core prepared through ionic gelation with tripolyphosphate. A polyamine modified F(ab') portion of IgG4.1, an anti-amyloid antibody, was coated as a biosensor on the SNV surface. A similar polymeric core coated with bovine serum albumin (BSA) served as a control nano-vehicle (CNV). The BBB uptake of ¹²⁵I-SNVs and ¹²⁵I-CNVs was evaluated in mice. The uptake and transcytosis of SNVs and CNVs across bovine brain microvascular endothelial cells (BBMECs) was evaluated using flow cytometry and confocal microscopy. Results. Plasma clearance of ¹²⁵I-SNVs was nine times higher than that of the ¹²⁵I- CNVs. However, the uptake of ¹²⁵I-SNVs in various brain regions was about 8 to 11 times higher than that of ¹²⁵I-CNVs. The uptake of FITC-BSA loaded SNVs in BBMECs was twice the uptake of FITC-BSA loaded CNVs. Confocal micrographs demonstrated the uptake and transcytosis of Alexa Fluor 647 labeled SNVs, but not CNVs, across the BBMEC monolayer. Conclusions. SNVs are capable of carrying a payload of model protein across the BBB to target cerebral amyloid.