Drug-Loaded Nanoparticles Targeted to the Colon With Polysaccharide Hydrogel Reduce Colitis in a Mouse Model

Background & Aims

One of the challenges to treating inflammatory bowel disease (IBD) is to target the site of inflammation. We engineered nanoparticles (NPs) to deliver an anti-inflammatory tripeptide Lys-Pro-Val (KPV) to the colon and assessed its therapeutic efficacy in a mouse model of colitis.

Methods

NPs were synthesized by double-emulsion/solvent evaporation. KPV was loaded into the NPs during the first emulsion of the synthesis process. To target KPV to the colon, loaded NPs (NP-KPV) were encapsulated into a polysaccharide gel containing 2 polymers: alginate and chitosan. The effect of KPV-loaded NPs on inflammatory parameters was determined in vitro as well as in the dextran sodium sulfate–induced colitis mouse model.

Results

NPs (400 nm) did not affect cell viability or barrier functions. A swelling degree study showed that alginate-chitosan hydrogel containing dextran–fluorescein isothiocyanate–labeled NPs collapsed in the colon. Once delivered, NPs quickly released KPV on or within the closed area of colonocytes. The inflammatory responses to lipopolysaccharide were reduced in Caco2–BBE (brush border enterocyte) cells exposed to NP-KPV compared with those exposed to NPs alone, in a dose-dependent fashion. Mice given dextran sodium sulfate (DSS) followed by NP-KPV were protected against inflammatory and histologic parameters, compared with mice given only DSS.

Conclusions

Nanoparticles are a versatile drug delivery system that can overcome physiologic barriers and target anti-inflammatory agents such as the peptide KPV to inflamed areas. By using NPs, KPV can be delivered at a concentration that is 12,000-fold lower than that of KPV in free solution, but with similar therapeutic efficacy. Administration of encapsulated drug-loaded NPs is a novel therapeutic approach for IBD.

Keywords: Colon Targeting, Colitis, KPV-Loaded Nanoparticle, Polysaccharide Hydrogel

Abbreviations used in this paper: BSA, bovine serum albumin, COX-2, cyclooxygenase-2, DSS, dextran sodium sulfate, ECIS, electrical impedance sensing, FITC, fluorescein isothiocyanate, IL, interleukin, LPS, lipopolysaccharide, MPO, myeloperoxidase, NP, nanoparticle, PCS, photon correlation spectroscopy, PLA, polylactide, PVA, polyvinyl alcohol, TNF, tumor necrosis factor