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Microspheres prepared with different co-polymers of poly(lactic-glycolic acid) (PLGA) or with chitosan cause distinct
Claudia da Silva Bitencourt1, Letícia Bueno da Silva2, Priscilla Aparecida Tartari Pereira2
1Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo. Ribeirão Preto, SP, 14040-903, Brazil; Centro Universitário das Faculdades Associadas ao Ensino (UNIFAE), São João da Boa Vista, SP, 13870-377, Brazil.
Abstract:
Microencapsulation of bioactive molecules for modulating the immune response during infectious or inflammatory events is a promising approach, since microspheres (MS) protect these labile biomolecules against fast degradation, prolong the delivery over longer periods of time and, in many situations, target their delivery to site of action, avoiding toxic side effects. Little is known, however, about the influence of different polymers used to prepare MS on macrophages. This paper aims to address this issue by evaluating in vitro cytotoxicity, phagocytosis profile and cytokines release from alveolar macrophages (J-774.1) treated with MS prepared with chitosan, and four different co-polymers of PLGA [poly (lactic-co-glycolic acid)]. The five MS prepared presented similar diameter and zeta potential each other. Chitosan-MS showed to be cytotoxic to J-774.1 cells, in contrast to PLGA-MS, which were all innocuous to this cell linage. PLGA 5000-MS was more efficiently phagocytized by macrophages compared to the other MS tested. PLGA 5000-MS and 5002-MS induced significant production of TNF-α, while 5000-MS, 5004-MS and 7502-MS decreased spontaneous IL-6 release. Nevertheless, only PLGA 5002-MS induced significant NFkB/SEAP activation. These findings together show that MS prepared with distinct PLGA co-polymers are differently recognized by macrophages, depending on proportion of lactic and glycolic acid in polymeric chain, and on molecular weight of the co-polymer used. Selection of the most adequate polymer to prepare a microparticulate drug delivery system to modulate immunologic system may take into account, therefore, which kind of immunomodulatory response is more adequate for the required treatment.
Insights
This study reveals that different poly (lactic-co-glycolic acid) [PLGA] microspheres influence macrophage behavior, impacting immune responses. PLGA microspheres offer a safer alternative to chitosan for drug delivery systems targeting the immune system.
Area of Science:
- Biomaterials Science
- Immunology
- Drug Delivery Systems
Background:
- Microencapsulation using microspheres (MS) protects bioactive molecules, prolongs delivery, and targets action sites, minimizing side effects.
- The impact of various polymers used in MS preparation on macrophage behavior remains largely unexplored.
Purpose of the Study:
- To investigate the in vitro effects of chitosan and different poly (lactic-co-glycolic acid) [PLGA] microspheres on alveolar macrophages.
- To evaluate cytotoxicity, phagocytosis, and cytokine release profiles of macrophages exposed to various MS formulations.
Main Methods:
- Preparation of five types of microspheres (MS): one chitosan-based and four based on different PLGA co-polymers.
- In vitro assessment of J-774.1 macrophage response including cytotoxicity assays, phagocytosis efficiency, and quantification of released cytokines (TNF-α, IL-6) and NFkB/SEAP activation.
Main Results:
- Chitosan-MS exhibited cytotoxicity, while all PLGA-MS were non-toxic to J-774.1 cells.
- PLGA 5000-MS demonstrated higher phagocytosis rates compared to other MS.
- Specific PLGA co-polymers differentially modulated cytokine release (TNF-α, IL-6) and NFkB/SEAP activation, indicating varied immune responses.
Conclusions:
- The composition and molecular weight of PLGA co-polymers significantly influence macrophage recognition and response.
- PLGA-based microspheres offer tunable immunomodulatory properties for developing targeted drug delivery systems.
- Careful selection of PLGA co-polymers is crucial for designing effective microparticulate systems to modulate the immune system for specific therapeutic outcomes.
