RESUMO
PURPOSE: Recombinant osteoprotegerin (OPG) has been proven to be useful for treating various bone disorders such as osteoporosis. To improve its in vivo pharmacological effect, OPG was conjugated to novel comb-shaped co-polymers of polyethylene glycol (PEG) allylmethylether and maleamic acid (poly(PEG), 5 kDa). Biodistribution and bioactivity were evaluated. METHODS: OPG was conjugated via lysine to poly(PEG) and to linear PEG (0.5 kDa and 5 kDa). Poly(PEG)-OPG was compared with linear PEG0.5k-OPG and PEG5k-OPG in terms of in vitro and in vivo efficacy and bone distribution. RESULTS: The in vitro receptor binding study showed that poly(PEG)-OPG could be the most bioactive among the three PEG-OPG derivatives. Pharmacokinetic studies in ovariectomized (OVX) rats showed that serum half-life and AUC of poly(PEG)-OPG were comparable with those of linear PEG-OPG derivatives. For in vivo pharmacological effect, poly(PEG)-OPG showed the strongest inhibitory effect on bone resorption activity in OVX rats. Poly(PEG)-OPG demonstrated enhanced bone marrow distribution with higher selectivity than linear PEG5k-OPG. CONCLUSION: Poly(PEG) modification could provide longer residence time in serum and higher bone-marrow specific delivery of OPG, leading to a higher in vivo pharmacological effect.
Assuntos
Osso e Ossos/efeitos dos fármacos , Osso e Ossos/metabolismo , Osteoclastos/efeitos dos fármacos , Osteoprotegerina/administração & dosagem , Osteoprotegerina/química , Polietilenoglicóis/administração & dosagem , Administração Intravenosa , Animais , Medula Óssea/efeitos dos fármacos , Medula Óssea/metabolismo , Reabsorção Óssea/tratamento farmacológico , Reabsorção Óssea/metabolismo , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Feminino , Humanos , Maleatos/administração & dosagem , Maleatos/química , Osteoclastos/metabolismo , Osteoprotegerina/farmacocinética , Ovariectomia/métodos , Polietilenoglicóis/química , Polímeros/administração & dosagem , Polímeros/química , Ratos , Ratos Endogâmicos F344 , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacocinética , Relação Estrutura-Atividade , Distribuição TecidualRESUMO
OBJECTIVES: Our aim was to investigate the effect of PEGylation on the uptake of osteoprotegerin/osteoclastogenesis inhibitory factor (OPG/OCIF) into rat liver, kidney and spleen, and human liver. METHODS: Copolymer of polyethyleneglycol allylmethylether and maleamic acid sodium salt with OCIF (poly(PEG)-OCIF) (0.5 mg/kg) was administered to rats and the concentrations of poly(PEG)-OCIF in the liver, kidney and spleen at 15 min after administration were measured by ELISA. For human liver uptake, the liver perfusion of OCIF and (3)H-labelled poly(PEG)-OCIF was conducted using fresh human liver block. KEY FINDINGS: The tissue uptake of poly(PEG)-OCIF in rats was significantly lower compared with that of OCIF. In fresh human liver perfusion, (3)H-poly(PEG)-OCIF was rarely taken up into the liver. On the other hand, more than 50% of the perfused OCIF was taken up. CONCLUSIONS: PEGylation of OCIF using poly(PEG) dramatically suppressed the uptake of OCIF into human liver as well as into rat liver and could be a promising approach for improving the pharmacokinetic and pharmacological effects of OCIF in the clinical setting.