RESUMO
BACKGROUND AND OBJECTIVE: Chitosan is a naturally derived polymer that may be applied in periodontal therapy for tissue-reconstruction purposes. Previous studies have shown that chitosan may stimulate tissue healing. However, reports exploring the cellular responses stimulated by chitosan are lacking. In the present study we analyzed whether chitosan may promote cell proliferation in primary cultures of human gingival fibroblasts. MATERIAL AND METHODS: Chitosan particles were generated, and their size, zeta potential and morphology were characterized using transmission and scanning electron microscopy and zetasizer analysis. The biocompatibility of chitosan particles was analyzed using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) cell-viability assay and by detecting the release of lactate dehydrogenase into the cell-culture medium. The total number of cells was estimated by staining with crystal violet followed by measurement of the absorbance at 560 nm on a microplate reader. Cell proliferation was studied by detecting proliferating cell nuclear antigen protein levels, immunofluorescence for Ki67 and incorporation of 5'-bromo-2'-deoxyuridine. RESULTS: The sizes of the chitosan particles generated were in the micrometer and nanometer ranges. Cell viability was increased in the presence of chitosan. Moreover, the combination of chitosan and platelet-derived growth factor (PDGF-BB) potently stimulated cell viability, cell proliferation and activation of the ERK1/2 pathway involved in cell proliferation. CONCLUSIONS: The present study shows that chitosan is well tolerated by gingival fibroblasts and is able to stimulate cell proliferation through the ERK1/2 signaling pathway. A synergistic response between chitosan and growth factors (such as PDGF-BB) may stimulate cell proliferation in gingival fibroblasts exposed to this biomaterial.
Assuntos
Indutores da Angiogênese/farmacologia , Materiais Biocompatíveis/farmacologia , Quitosana/farmacologia , Fibroblastos/efeitos dos fármacos , Gengiva/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-sis/farmacologia , Becaplermina , Materiais Biocompatíveis/química , Bromodesoxiuridina , Contagem de Células , Técnicas de Cultura de Células , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Quitosana/química , Corantes , Sinergismo Farmacológico , Violeta Genciana , Gengiva/citologia , Humanos , Antígeno Ki-67/análise , Antígeno Ki-67/efeitos dos fármacos , L-Lactato Desidrogenase/análise , L-Lactato Desidrogenase/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanopartículas/química , Tamanho da Partícula , Antígeno Nuclear de Célula em Proliferação/análise , Antígeno Nuclear de Célula em Proliferação/efeitos dos fármacos , Sais de Tetrazólio , TiazóisRESUMO
Immune thrombocytopenic purpura (ITP) is a bleeding disorder characterized by accelerated splenic removal of platelets opsonized with autoantibodies. Several different treatments have been tried in acute ITP patients, including intravenous immunoglobulin (IVIG) therapy. The aim of this paper was to assess the therapeutic efficacy, clinical tolerance and viral safety of Inmunoglobulina G Endovenosa-UNC, manufactured by Laboratorio de Hemoderivados, Cordoba National University, in the treatment of acute ITP patients. A prospective longitudinal study was carried out on 8 children, who were admitted to the Hospital de Niños de Córdoba, from July 1998 to June 1999. A dose of 1 g/Kg/day of Inmunoglobulina G Endovenosa-UNC was administered to those children whose platelet values remained < or = 20,000/mm3, 21 days after the first IVIG cycle. The observed results led us to conclude that Inmunoglobulina G Endovenosa-UNC is well tolerated and therapeutically effective in the treatment of acute ITP in children, with platelet values recovery, similar to those obtained with other IVIG. Moreover, it proved to be virally safe since the 8 patients were non reactive for viral markers of hepatitis B, hepatitis C and human immunodeficiency, 12 months after ending the treatment.
Assuntos
Imunoglobulinas Intravenosas/uso terapêutico , Púrpura Trombocitopênica Idiopática/tratamento farmacológico , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Estudos Longitudinais , Masculino , Contagem de Plaquetas , Estudos Prospectivos , Púrpura Trombocitopênica Idiopática/sangue , Resultado do TratamentoRESUMO
Immune thrombocytopenic purpura (ITP) is a bleeding disorder characterized by accelerated splenic removal of platelets opsonized with autoantibodies. Several different treatments have been tried in acute ITP patients, including intravenous immunoglobulin (IVIG) therapy. The aim of this paper was to assess the therapeutic efficacy, clinical tolerance and viral safety of Inmunoglobulina G Endovenosa-UNC, manufactured by Laboratorio de Hemoderivados, Cordoba National University, in the treatment of acute ITP patients. A prospective longitudinal study was carried out on 8 children, who were admitted to the Hospital de Niños de Córdoba, from July 1998 to June 1999. A dose of 1 g/Kg/day of Inmunoglobulina G Endovenosa-UNC was administered to those children whose platelet values remained < or = 20,000/mm3, 21 days after the first IVIG cycle. The observed results led us to conclude that Inmunoglobulina G Endovenosa-UNC is well tolerated and therapeutically effective in the treatment of acute ITP in children, with platelet values recovery, similar to those obtained with other IVIG. Moreover, it proved to be virally safe since the 8 patients were non reactive for viral markers of hepatitis B, hepatitis C and human immunodeficiency, 12 months after ending the treatment.