title: Docosahexaenoic acid loaded lipid nanoparticles with bactericidal activity against Helicobacter pylori.
abstract: Docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid present in fish oil, has been described as a promising molecule to the treatment of Helicobacter pylori gastric infection. However, due to its highly unsaturated structure, DHA can be easily oxidized loosing part of its bioactivity. This work aims the nanoencapsulation of DHA to improve its bactericidal efficacy against H. pylori. DHA was loaded into nanostructured lipid carriers (NLC) produced by hot homogenization and ultrasonication using a blend of lipids (Precirol ATO5®, Miglyol-812®) and a surfactant (Tween 60®). Homogeneous NLC with 302±14nm diameter, -28±3mV surface charge (dynamic and electrophoretic light scattering) and containing 66±7% DHA (UV/VIS spectroscopy) were successfully produced. Bacterial growth curves, performed over 24h in the presence of different DHA concentrations (free or loaded into NLC), demonstrated that nanoencapsulation enhanced DHA bactericidal effect, since DHA-loaded NLC were able to inhibit H. pylori growth in a much lower concentrations (25μM) than free DHA (>100μM). Bioimaging studies, using scanning and transmission electron microscopy and also imaging flow cytometry, demonstrated that DHA-loaded NLC interact with H. pylori membrane, increasing their periplasmic space and disrupting membrane and allowing the leakage of cytoplasmic content. Furthermore, the developed nanoparticles are not cytotoxic to human gastric adenocarcinoma cells at bactericidal concentrations. DHA-loaded NLC should, therefore, be envisaged as an alternative to the current treatments for H. pylori infection.
authors.affiliation: i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Portugal; IPATIMUP-Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Portugal; ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Portugal.
authors.forename: Catarina Leal
authors.initials: CL
authors.lastname: Seabra
authors.affiliation: UCIBIO, REQUIMTE, Laboratório de Química Aplicada, Faculdade de Farmácia, Universidade do Porto, Portugal.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Nunes
authors.affiliation: i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Portugal.
authors.forename: Maria
authors.initials: M
authors.lastname: Gomez-Lazaro
authors.affiliation: Escola da Saúde, Universidade do Algarve, Portugal.
authors.forename: Marta
authors.initials: M
authors.lastname: Correia
authors.affiliation: i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; IPATIMUP-Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Portugal; Faculdade de Medicina, Universidade do Porto, Portugal.
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Machado
authors.affiliation: i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Portugal.
authors.forename: Inês C
authors.initials: IC
authors.lastname: Gonçalves
authors.affiliation: i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; IPATIMUP-Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Portugal; ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Portugal; Faculdade de Medicina, Universidade do Porto, Portugal.
authors.forename: Celso A
authors.initials: CA
authors.lastname: Reis
authors.affiliation: UCIBIO, REQUIMTE, Laboratório de Química Aplicada, Faculdade de Farmácia, Universidade do Porto, Portugal.
authors.forename: Salette
authors.initials: S
authors.lastname: Reis
authors.affiliation: i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Portugal; IPATIMUP-Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Portugal. Electronic address: cmartins@ineb.up.pt.
authors.forename: M Cristina L
authors.initials: MCL
authors.lastname: Martins
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D045744:Cell Line, Tumor; D004281:Docosahexaenoic Acids / Q000737:chemistry* / Q000494:pharmacology*; D004337:Drug Carriers / Q000737:chemistry; D005395:Fish Oils / Q000737:chemistry; D016481:Helicobacter Infections / Q000188:drug therapy; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D008055:Lipids / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry; D010316:Particle Size; D011136:Polysorbates / Q000737:chemistry; D013270:Stomach / Q000382:microbiology; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D004337:Drug Carriers; D005395:Fish Oils; D008055:Lipids; D011136:Polysorbates; D013501:Surface-Active Agents; D004281:Docosahexaenoic Acids
keywords: Docosahexaenoic acid (DHA); Helicobacter pylori; Nanostructured lipid carriers (NLC); Polyunsaturated fatty acid (PUFA)