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1.
Int J Biol Macromol ; 189: 324-334, 2021 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-34419549

RESUMO

Chitosan is a polymer derived from the partial deacetylation of chitin with particular characteristics, such as mucoadhesiveness, tolerability, biocompatibility and biodegradability. Biomedical uses of chitosan cover a wide spectrum of applications as dietary fiber, immunoadjuvant and regulator of the intestinal microbiota or delivery agent. Chemical modification of chitosan is feasible because its reactive amino and hydroxyl groups can be modified by a diverse array of ligands, functional groups and molecules. This gives rise to numerous derivatives that allow different formulation types influencing their activity. Considering the multiple events resulting from the interaction with mucosal tissues, chitosan is a singular candidate for strategies targeting immune stimulation (i.e., tolerance induction, vaccination). Its role as a prebiotic and probiotic carrier represents an effective option to manage intestinal dysbiosis. In the intestinal scenario where the exposure of the immune system to a wide variety of antigens is permanent, chitosan increases IgA levels and favors a tolerogenic environment, thus becoming a key ally for host homeostasis.


Assuntos
Quitosana/farmacologia , Mucosa Intestinal/imunologia , Adjuvantes Imunológicos/farmacologia , Animais , Sistemas de Liberação de Medicamentos , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/microbiologia , Microbiota/efeitos dos fármacos , Probióticos/farmacologia
2.
Cell Prolif ; 42(6): 780-7, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19689471

RESUMO

OBJECTIVE: After oral administration of chitosan (a copolymer of glucosamine and N-acetylglucosamine), mesenteric lymph node (MLN) lymphocytes exhibited traits of anergy, a process coupled with inability of mature T cells to proliferate. We wondered whether biological activity of chitosan could be affecting division of lymphocytes at the mucosal inductive sites. MATERIALS AND METHODS: We studied the effect of chitosan on proliferation of carboxyfluorescein diacetate-labelled MLN lymphocytes stimulated with concanavalin A in vitro. We assessed expression of CD25 and CD71 activation markers and pro-apoptotic molecule CD95L. Moreover, we studied the effect of chitosan ex vivo, in carboxyfluorescein diacetate-labelled MLN cells isolated after feeding single or repetitive doses of the polysaccharide, and we evaluated cell cycle parameters. RESULTS: Chitosan suppressed cell proliferation and down-modulated expression of CD25 in these MLN CD4+ cells isolated from normal rats. After in vivo contact, chitosan inhibited proliferation of MLN cells and reduced secretion of interferon-gamma. Furthermore, sustained feeding produced reduction in percentage of CD4+ cells in S phase of the cell cycle. CONCLUSION: Here we demonstrate the ability of chitosan to suppress proliferation of CD4+ lymphocytes from mucosal inductive sites in vivo and in vitro This effect could be relevant in modulatory activity of chitosan in the intestinal microenvironment.


Assuntos
Linfócitos T CD4-Positivos/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Quitosana/farmacologia , Animais , Linfócitos T CD4-Positivos/citologia , Ciclo Celular , Citocinas/biossíntese , Citometria de Fluxo , Técnicas In Vitro , Ratos , Ratos Wistar
3.
Clin Exp Immunol ; 155(1): 79-87, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19076832

RESUMO

Chitosan is a mucoadhesive polysaccharide that promotes the transmucosal absorption of peptides and proteins. At mucosal sites chitosan exhibits immunomodulatory activities and stimulates the release of regulatory cytokines. Herein we evaluated the effect of the co-administration of chitosan in the tolerance to type II collagen (CII) using an experimental model of arthritis. Rats were fed diluent (acetic acid), 1 mg CII, 1 mg chitosan or 1 mg CII + 1 mg chitosan during 5 days before immunization with CII in Freund's complete adjuvant. Systemic effects were evaluated in draining lymph nodes after antigenic challenge or during the clinical evolution of arthritis. Specific antibodies, proliferation against CII and the production of interferon (IFN)-gamma and interleukin-10 were assessed. Clinical signs were observed 13-15 days after primary immunization. The CII : chitosan group presented the lowest incidence and developed moderate arthritis, with reduced levels of immunoglobulin (Ig)G2a anti-CII, a limited proliferation in draining lymph nodes and a lower release of IFN-gamma after restimulation with CII. Our results demonstrate that chitosan enhances the tolerance to an articular antigen with a decrease in the inflammatory responses and, as a consequence, an improvement in clinical signs.


Assuntos
Artrite Experimental/imunologia , Quitosana/administração & dosagem , Colágeno Tipo II/imunologia , Ácido Acético , Administração Oral , Animais , Quimiocina CCL2/imunologia , Quitosana/imunologia , Feminino , Adjuvante de Freund , Tolerância Imunológica/efeitos dos fármacos , Imunização , Imunoglobulina G/sangue , Interferon gama/imunologia , Interleucina-10/imunologia , Linfonodos/imunologia , Ratos , Ratos Wistar , Baço/imunologia
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