Liposome-Encapsulated Neuropeptides for Site-Specific Microinjection

Abstract

This paper describes an experimental approach based on nanotechnology for assessing the chronic actions of short-lived neuropeptides at specific sites of the brain. This methodology combines the advantages of two different techniques: the microinjection of a suspension of peptide-containing liposomes into a specific site of the brain, and the use of liposomes as a local and sustained release nanosystem of the peptide.

Liposome-entrapped GABA modulates the expression of nNOS in NG108-15 cells

“…Accordingly, in vivo release study, with this same preparation (Vaz et al, 2015) indicated a sustained release of GABA from liposomes, with only ~60% of GABA release after 5 days of incubation at 37°C. Other important characteristics of these liposomes are their mean diameter of 200 nm and the incorporation of a pegylated lipid, to slow down their capture by cells for endocytosis/phagocytosis and the cell-mediated release of encapsulated drug (Frezard et al, 2011). However, the early response after exposure of NG108-15 to GL suggests that liposome capture by these cells takes place and exerts a significant effect on the proteins measured in this study.…”

GABA-containing liposomes: neuroscience applications and translational perspectives for targeting neurological diseases

“…Liposomes are microscopic spherical vesicles, consisting of one or more concentric lipid bilayers, which isolate one or more internal aqueous compartments from external medium (Figure 1) [3,22]. They may encapsulate hydrophilic and/or lipophilic substances in the inner aqueous compartment and in the membrane respectively.…”

“…Importantly, the membrane fluidity and surface of liposomes can be manipulated to control the drug release from liposomes. For instance, more rigid membranes usually result in lower rates of drug release [3]. When the cell-mediated drug release mechanism predominates, PEGylated liposomes also promote slower drug release.…”

“…The formulation employed was developed only with natural phosphatidylserine [32,33]. Natural phosphatidylserine is expected to form less stable and more leaky vesicles [3] and to favor the capture of liposomes by macrophages [34]. Furthermore, important characteristics such as size and kinetic of GABA release were not determined [32,33].…”

“…Accordingly, in vitro results indicate a very slow release of GABA from liposomes, with only 60% of GABA release after 5 days of incubation at 37°C. Other important characteristics of these liposomes were their mean diameter of 200 nm and the incorporation of a pegylated lipid, to slow down their capture by cells, by endocytosis/phagocytosis and the cell-mediated release of encapsulated drug [3].…”