title: Enhanced glutathione PEGylated liposomal brain delivery of an anti-amyloid single domain antibody fragment in a mouse model for Alzheimer's disease.
abstract: Treatment of neurodegenerative disorders such as Alzheimer's disease is hampered by the blood-brain barrier (BBB). This tight cerebral vascular endothelium regulates selective diffusion and active transport of endogenous molecules and xenobiotics into and out of the brain parenchyma. In this study, glutathione targeted PEGylated (GSH-PEG) liposomes were designed to deliver amyloid-targeting antibody fragments across the BBB into the brain. Two different formulations of GSH-PEG liposomes based on 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and egg-yolk phosphatidylcholine (EYPC) were produced. Both formulations encapsulate 15kDa amyloid beta binding llama single domain antibody fragments (VHH-pa2H). To follow the biodistribution of VHH-pa2H rather than the liposome, the antibody fragment was labeled with the radioisotope indium-111. To prolong the shelf life of the construct beyond the limit of radioactive decay, an active-loading method was developed to efficiently radiolabel the antibody fragments after encapsulation into the liposomes, with radiolabeling efficiencies of up to 68% after purification. The radiolabeled liposomes were administered via a single intravenous bolus injection to APPswe/PS1dE9 double transgenic mice, a mouse model of Alzheimer's disease, and their wildtype littermates. Both GSH-PEG DMPC and GSH-PEG EYPC liposomes significantly increased the standard uptake values (SUV) of VHH-pa2H in the blood of the animals compared to free VHH-pa2H. Encapsulation in GSH-PEG EYPC liposomes resulted in the highest increase in SUV in the brains of transgenic animals. Overall, these data provide evidence that GSH-PEG liposomes may be suitable for specific delivery of single domain antibody fragments over the BBB into the brain.
authors: Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands; Department of Radiology (Molecular Imaging Laboratories Leiden & Nuclear Medicine), Leiden University Medical Center, Leiden, The Netherlands.
authors: Maarten
authors: M
authors: Rotman
authors: Department of Radiology (Molecular Imaging Laboratories Leiden & Nuclear Medicine), Leiden University Medical Center, Leiden, The Netherlands.
authors: Mick M
authors: MM
authors: Welling
authors: Department of Radiology (Interventional Molecular Imaging Laboratory), Leiden University Medical Center, Leiden, The Netherlands.
authors: Anton
authors: A
authors: Bunschoten
authors: to-BBB technologies BV, Leiden, The Netherlands.
authors: Maaike E
authors: ME
authors: de Backer
authors: to-BBB technologies BV, Leiden, The Netherlands.
authors: Jaap
authors: J
authors: Rip
authors: Department of Radiology (Molecular Imaging Laboratories Leiden & Nuclear Medicine), Leiden University Medical Center, Leiden, The Netherlands.
authors: Rob J A
authors: RJ
authors: Nabuurs
authors: to-BBB technologies BV, Leiden, The Netherlands.
authors: Pieter J
authors: PJ
authors: Gaillard
authors: Department of Radiology (Molecular Imaging Laboratories Leiden & Nuclear Medicine), Leiden University Medical Center, Leiden, The Netherlands.
authors: Mark A
authors: MA
authors: van Buchem
authors: Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
authors: Silvère M
authors: SM
authors: van der Maarel
authors: Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands; Department of Radiology (Molecular Imaging Laboratories Leiden & Nuclear Medicine), Leiden University Medical Center, Leiden, The Netherlands. Electronic address: l.van_der_weerd@lumc.nl.
authors: Louise
authors: L
authors: van der Weerd
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism / Q000628:therapy*; D016229:Amyloid beta-Peptides / Q000037:antagonists & inhibitors*; D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002161:Camelids, New World; D004195:Disease Models, Animal; D016503:Drug Delivery Systems; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000008:administration & dosage / Q000627:therapeutic use; D008081:Liposomes / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D011092:Polyethylene Glycols / Q000378:metabolism; D057127:Single-Chain Antibodies / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000627:therapeutic use; D014018:Tissue Distribution
chemical_list: D016229:Amyloid beta-Peptides; D007143:Immunoglobulin Heavy Chains; D008081:Liposomes; D057127:Single-Chain Antibodies; D011092:Polyethylene Glycols; D005978:Glutathione
keywords: (111)In labeling; APP(swe)/PS1dE9 mice; G-Technology; Glutathione PEGylated liposomes; Llama antibodies; VHH