RESUMEN
In murine severe experimental autoimmune encephalomyelitis (EAE), an animal model for the human disease multiple sclerosis (MS), we tested the efficacy of a 5-halo-6-phenyl pyrimidinone compound, bropirimine (PNU-54461). We observed that the compound is active in suppressing EAE when administered orally, a significant pharmacological advantage compared to some current therapies for the treatment of MS. Furthermore, bropirimine was most efficacious when dosing was begun 5-10 days after injection of myelin basic protein, the protein isolated from the central nervous system and used for inducing EAE in our model. This is a period of time following the initial immunological events leading to the disease, when large-scale leukocyte infiltration into the central nervous system begins. Following oral dosing, bropirimine peaked in the blood within 3 h and was cleared to undetectable concentrations within 16-18 h. Despite the pharmacokinetics in the blood, bropirimine was fully efficacious when dosed orally every two or three days. Surprisingly, bropirimine treatment did not result in a statistically significant decrease in leukocyte infiltration into the lower spinal cord, unless the compound was dosed daily at a high concentration. We also observed the concentration and time course of alpha-interferon in blood following oral dosing of bropirimine. The kinetics of interferon in the blood are similar to, but clearly distinguishable from, the pharmacokinetics of bropirimine in the blood. It is not clear whether or not the induction of interferon plays a key role in the efficacy of bropirimine. Nevertheless, the results using bropirimine in EAE suggest that the compound may be useful for the treatment of multiple sclerosis.
Asunto(s)
Adyuvantes Inmunológicos/farmacología , Citosina/análogos & derivados , Encefalomielitis Autoinmune Experimental/prevención & control , Animales , Citosina/farmacocinética , Citosina/farmacología , Relación Dosis-Respuesta a Droga , Femenino , Hidroxiquinolinas/farmacología , Inmunohistoquímica , Interferones/sangre , Ratones , Esclerosis Múltiple/tratamiento farmacológicoRESUMEN
We showed previously that a 5-halo-6-phenyl-pyrimidinone, bropirimine (PNU-54461), inhibited progression of severe experimental autoimmune encephalomyelitis (EAE), an animal model of human multiple sclerosis. In the work presented here, we examined the activity of a group of chemically-related bropirimine analogues. First, the pharmacokinetic properties of the bropirimine analogues were examined in normal mice following oral dosing. After equal oral doses, both PNU-56169 and PNU-63693 were found in the blood of normal mice at equal or higher concentrations than bropirimine, but PNU-54462 and PNU-56359 were present in blood only at very low concentrations. Next, we examined the bropirimine analogues for activity in our model of severe EAE. At a dose of 400 mg/kg administered orally every second day PNU-56169 nearly completely blocked EAE progression, but was ineffective at 100 mg/kg. PNU-63693 was effective in EAE at concentrations of 200 mg/kg, 100 mg/kg, 50 mg/kg, and as low as 25 mg/kg. Histopathology was examined by observing leukocyte infiltration into the lower spinal cords of the mice. Treatment with 400 mg/kg of PNU-56169 and doses of 25, 50, 100, and 200 mg/kg of PNU-63693 significantly inhibited leukocyte infiltration into the lower spinal cord of treated mice in a dose-dependent manner. Orally administered PNU-56169 and PNU-63693 also stimulated significant concentrations of IFNalpha in the serum of treated mice, which may be related to the efficacy of the compounds in EAE. However, the correlation between IFNalpha in the blood and efficacy in treating EAE was not exact. Thus, PNU-56169 and PNU-63693 were delivered to the blood following oral dosing, induced significant concentrations of IFNalpha in the blood, and were equally or more potent than PNU-54461 in inhibiting clinical signs of EAE. The results suggest that 5-halo-6-phenyl-pyrimidinones are an interesting class of compounds to investigate for development in the treatment of multiple sclerosis.
Asunto(s)
Citosina/análogos & derivados , Citosina/uso terapéutico , Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Inductores de Interferón/uso terapéutico , Animales , Citosina/farmacocinética , Relación Dosis-Respuesta a Droga , Encefalomielitis Autoinmune Experimental/inmunología , Encefalomielitis Autoinmune Experimental/patología , Femenino , Inductores de Interferón/farmacocinética , Interferón gamma/sangre , Leucocitos/patología , Ratones , Médula Espinal/efectos de los fármacos , Médula Espinal/patologíaRESUMEN
Bisphosphonate ester 2 is an inhibitor of inflammation, but is devoid of antiarthritic effects. SAR studies on a series of related bisphosphonate esters resulted in compounds 6e, 6i, 6j, and 6m, which exhibited excellent inhibition of an arthritis model, in addition to potent anti-inflammatory effects.
Asunto(s)
Antiinflamatorios no Esteroideos/síntesis química , Artritis Experimental/tratamiento farmacológico , Difosfonatos/síntesis química , Inflamación/tratamiento farmacológico , Animales , Antiinflamatorios no Esteroideos/química , Antiinflamatorios no Esteroideos/uso terapéutico , Difosfonatos/química , Difosfonatos/uso terapéutico , Diseño de Fármacos , Granuloma/tratamiento farmacológico , Granuloma/inmunología , Hipersensibilidad Tardía , Indicadores y Reactivos , Ratones , Estructura Molecular , Relación Estructura-ActividadRESUMEN
A study of the decomposition of the pyrazoline bisphosphonate ester 2 identified 3 as the sole bisphosphonate component. Evaluation in a delayed-type hypersensitivity granuloma model of chronic inflammation in mice (DTH-GRA) showed 3 to be a potent inhibitor of granuloma formation (sc, 10 mg/kg, 45%), but in a murine model of antigen-induced arthritis (AIA), no significant inhibition was observed. As a result, new ketonic bisphosphonate tetraethyl esters were synthesized from vinylidenebisphosphonic acid tetraethyl ester 4 and activated carbonyl compounds in 13-84% yield. 6 significantly inhibited the pathology of both the DTH-GRA (sc, 25 mg/kg, 45%) and AIA models (sc, 25 mg/kg, 55%). Other compounds in the series were not as potent. Our results show that bisphosphonate ester 6 can inhibit the chronic inflammatory response associated with cutaneous granuloma formation and erosive arthritis.
Asunto(s)
Antiinflamatorios no Esteroideos/síntesis química , Artritis/tratamiento farmacológico , Difosfonatos/síntesis química , Animales , Antiinflamatorios no Esteroideos/farmacología , Difosfonatos/farmacología , Relación Dosis-Respuesta a Droga , Femenino , Ratones , Ratones Endogámicos C57BL , Relación Estructura-ActividadRESUMEN
Diphosphonates (DP) are synthetic pyrophosphates with a P-C-P backbone and are predominantly used for the treatment of bone diseases. Several DP have also been shown to exert significant antiarthritic effects in the rat adjuvant-induced polyarthritis model; however, there is no direct evidence for the anti-inflammatory effects of these compounds. We therefore tested the effects of dichloromethylene diphosphonate on delayed-type hypersensitivity granuloma elicited by s.c. implantation of antigen-soaked hydroxyapatite disks in antigen-sensitized mice. Dichloromethylene diphosphonate induced a dose-related inhibition of the delayed-type hypersensitivity granuloma response (38-64% at 25-100 mg/kg/day s.c. or p.o.); novel DP analogs, U-81581, U-82579 and U-84849 were also effective in the same dose range. In contrast, all DP failed to suppress 24-hr delayed-type hypersensitivity paw edema in mice. In addition to rat adjuvant-induced polyarthritis, mouse antigen-induced erosive arthritis was also significantly suppressed by s.c. administration of all four DP. Toxicity was minimal for each DP (> 600 mg/kg p.o. or s.c.). We conclude that DP represent a novel class of anti-inflammatory agents with excellent therapeutic potential for chronic inflammatory diseases including rheumatoid arthritis.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Artritis Experimental/tratamiento farmacológico , Difosfonatos/farmacología , Animales , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Edema/tratamiento farmacológico , Femenino , Granuloma de Cuerpo Extraño/tratamiento farmacológico , Hipersensibilidad Tardía/tratamiento farmacológico , Inflamación/tratamiento farmacológico , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos , Ratas , Ratas WistarRESUMEN
Vinylidenebisphosphonic acid tetraethyl ester (1) and diazo ketones 7a-1 in ether at 22 degrees C yield pyrazoline bisphosphonate tetraethyl esters 8a-1 in moderate to good yield. These compounds were evaluated in animal models of arthritis: rat adjuvant-induced polyarthritis (AIP) and murine antigen-induced arthritis (AIA) and a murine model of chronic inflammation, the delayed type hypersensitivity granuloma reaction (DTH-GRA). (5-Benzoyl-2,4-dihydro-3H-pyrazol-3-ylidene)-bisphosphonic acid tetraethyl ester (8a), and [5-(3-fluorobenzoyl)-2,4-dihydro-3H-pyraxol-3-ylidene]- bisphosphonic acid tetraethyl ester (8d) significantly inhibited the arthritis models, AIP (15 mg/kg) and AIA (25 mg/kg), as well as the DTH-GRA (25 mg/kg). Conversion of 8a to the corresponding bisphosphonic acid, 10a, resulted in loss of activity. Compounds with alkyl substituents on the pyrazoline nitrogen, 9a-d, were inactive in the DTH-GRA. These results show that 8a and 8d have novel antiinflammatory activity and are capable of inhibiting chronic arthritis and inflammation in animals. Such compounds might be useful in man for treating chronic tissue injury associated with arthropathies such as inflammatory joint disease as well as other chronic inflammatory diseases.
Asunto(s)
Antiinflamatorios no Esteroideos/síntesis química , Difosfonatos/síntesis química , Pirazoles/síntesis química , Animales , Artritis/tratamiento farmacológico , Difosfonatos/química , Difosfonatos/farmacología , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Pirazoles/química , Pirazoles/farmacología , Ratas , Ratas Wistar , Relación Estructura-ActividadRESUMEN
We examined the effect of interleukin-1 (IL-1) administration on a mild and transient inflammatory response in the knees of mice injected intraarticularly with methylated bovine serum albumin (mBSA). Injection of mBSA on day 0 into nonsensitized mice caused a weak inflammatory response confined to the infrapatellar fat pads and involved infiltration by mononuclear cells, neutrophils, and eosinophils. The response developed between days 4 and 7 and resolved by day 28. No erosion of cartilage or subchondral bone was seen. In contrast, mBSA-treated mice injected with recombinant human IL-1 beta subcutaneously in the ipsilateral footpad on days 0-3 developed a severe monarticular arthritis in the antigen-injected knee. Pannus developed, extending over the articular surfaces, and extensive erosion of cartilage and subchondral bone occurred. Multinucleated giant cells, together with fibrin-like material, were observed at sites of active bone erosion and debris, and large numbers of neutrophils were seen in the joint space. These pathologic features represent a new arthritis model in which IL-1 profoundly augments a weak inflammatory response and induces acute erosive joint destruction, supporting the hypothesis that IL-1 is an important cytokine in the pathogenesis of arthritis.
Asunto(s)
Artritis Experimental/etiología , Artritis/etiología , Interleucina-1 , Albúmina Sérica Bovina , Enfermedad Aguda , Animales , Artritis Experimental/patología , Cartílago Articular/patología , Femenino , Inyecciones Intraarticulares , Interleucina-1/administración & dosificación , Articulación de la Rodilla/patología , Ratones , Ratones Endogámicos C57BL , Neutrófilos , Albúmina Sérica Bovina/administración & dosificación , Factores de TiempoRESUMEN
The present study examined the effects of five different classes of anti-inflammatory/immunoregulatory drugs using a mouse model of mBSA-induced delayed-type hypersensitivity granuloma (DTH GRA) to measure immune-mediated chronic inflammatory tissue formation. The compounds were administered orally daily following induction of DTH GRA (days 0 to 4); granulomata were quantitated gravimetrically on day 5. NSAIDs, with the exception of flurbiprofen, showed little activity in comparison with the steroids dexamethasone (1-3 mg/kg/day, orally) and prednisolone (3-10 mg/kg/day, orally), which caused significant suppression of DTH GRA tissue (65-76% and 26-68%, respectively). The "immunoregulatory" compounds levamisole and D(-)penicillamine were inactive, whereas cyclophosphamide (5-50 mg/kg/day, orally) reduced the response by 24-83%. The "interferon alpha-inducers" Tilorone, U-54,461, and U-56,499 were also potent inhibitors of the DTH GRA response; U-54,462, a weak interferon alpha-inducer, was inactive. Cyclosporin A (50-100 mg/kg/day, orally) suppressed DTH GRA most effectively when administered on days 3 and 4 (66% and 97%) of the five-day granuloma response (treatment was ineffective when given on days 1 and 2). We conclude that the DTH GRA response described above may be useful for evaluating different types of unique therapeutic agents that are effective in the treatment of chronic immuno-inflammatory disease such as rheumatoid arthritis.