RESUMO
Phosphodiesterase (PDE) inhibition has been broadly investigated as a target for a wide variety of indications including central nervous system (CNS) disorders. Cyclic nucleotide (cNT) changes within associated tissues may serve as a biomarker of PDE inhibition. We recently developed robust sample harvesting and bioanalytical methods to quantify cNT levels in rodent brain and cerebrospinal fluid (CSF). Herein, we report on the application of those methods to study rodent species-specific and rodent brain region-specific cNT changes following individual or concomitant PDE inhibitor administration. Male Sprague Dawley (Crl:CD® [SD]) rats were dosed subcutaneously (sc) with a PDE1B inhibitor (DNS-0056), a PDE2A inhibitor (PF-05180999), a PDE9A inhibitor (PF-4447943), and a PDE10A inhibitor (MP10), each at a single dose of 10 or 30â¯mg/kg, or concomitantly with all 4 inhibitors at 10â¯mg/kg each. Male Carworth Farms (Crl:CF1 ®[CF-1]) mice were dosed intraperitoneally (ip) with the four individual inhibitors at a single dose of 10â¯mg/kg or concomitantly with all 4 inhibitors at 10â¯mg/kg each. The doses studied are generally adequate for affecting measurable cNT levels in the tissues of interest and were thereby chosen for this investigation. Measured 3',5'-cyclic adenosine monophosphate (cAMP) changes were generally statistically insignificant in the brain, striatum and CSF after administration of the aforementioned PDE inhibitors. However, the levels of 3',5'-cyclic guanosine monophosphate (cGMP) increased in both rat and mouse striatum (2.2-, 2.1- and 1.7-fold and 6.4-, 2.8- and 1.7-fold, respectively) after PDE2A, 9A, and 10A inhibitor dosing. In all cases, the cNT changes followed the same trend in the brain, striatum and CSF after PDE inhibitor dosing and dose response was observed in rats. Concomitant treatment with PDE1B, PDE2A, PDE9A and PDE10A inhibitors resulted in a 4.4- and 36.7-fold increase of cGMP in rat and mouse striatum. The drug exposures after concomitant treatment were also higher than in the individual inhibitor-treated animals. cGMP enhancement observed could be due to synergistic effects, though an additive effect of the combined inhibitor concentrations may also contribute.
Assuntos
Sistema Nervoso Central/efeitos dos fármacos , Nucleotídeo Cíclico Fosfodiesterase do Tipo 1/antagonistas & inibidores , Inibidores de Fosfodiesterase/farmacologia , Diester Fosfórico Hidrolases/efeitos dos fármacos , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Sistema Nervoso Central/metabolismo , AMP Cíclico/metabolismo , GMP Cíclico/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 1/metabolismo , Masculino , Camundongos , Inibidores de Fosfodiesterase/química , Diester Fosfórico Hidrolases/metabolismo , Ratos Sprague-DawleyRESUMO
BACKGROUND: Treatment of rare severe side effects of vaccinia virus (VACV) immunization in humans is currently very challenging. VACV possesses two immunologically distinct virion forms in vivo - intracellular mature virion (MV, IMV) and extracellular virion (EV, EEV). METHODS: Antibody-mediated therapeutic efficacy was determined against VACV infection in a small animal model of progressive vaccinia. The model consisted of severe combined immunodeficiency mice infected with VACV New York City Board of Health vaccine strain and treated with monoclonal antibodies (mAbs). RESULTS: Here, we show that combination therapy with two fully human mAbs against an immunodominant MV antigen, H3 (H3L), and an EV antigen, B5 (B5R), provides significantly better protection against disease and death than either single human monoclonal or human vaccinia immune globulin, the currently licensed therapeutic for side effects of smallpox vaccination. CONCLUSIONS: The preclinical studies validate that this combination of mAbs against H3 and B5 is a promising approach as a poxvirus infection treatment for use in humans.