Conclusion
The EVs-DNZ formulation was more efficient to inhibit the AChE enzyme activity in the zebrafish larvae head. Thus, the bioinspired delivery system (EVs) is a promising alternative strategy for brain-targeted delivery by substantially improving the activity of DNZ for the treatment of AD.
Methods
EVs were isolated from human plasma and PLA-PEG NPs were synthesized by nanoprecipitation. The toxicity, brain targeting capacity and cholinergic activities of the formulations were evaluated both in vitro and in vivo.
Results
EVs and NPs-PLA-PEG were designed to be similar in size and charge, efficiently encapsulated DNZ and allowed sustained drug release. In vitro study showed that both formulations EVs-DNZ and NPs-PLA-PEG-DNZ were highly internalized by the endothelial cells bEnd.3. These cells cultured on the Transwell® model were used to analyze the transcytosis of both formulations after validation of the presence of tight junctions, the transendothelial electrical resistance (TEER) values and the permeability of the Dextran-FITC. In vivo study showed that both formulations were not toxic to zebrafish larvae (Danio rerio). However, hyperactivity was evidenced in the NPs-PLA-PEG-DNZ and free DNZ groups but not the EVs-DNZ formulations. Biodistribution analysis in zebrafish larvae showed that EVs were present in the brain parenchyma, while NPs-PLA-PEG remained mainly in the bloodstream.