RESUMEN
Research toward a next-generation HCV NS5A inhibitor has identified fluorobenzimidazole analogs that demonstrate potent, broad-genotype in vitro activity against HCV genotypes 1-6 replicons as well as HCV NS5A variants that are orders of magnitude less susceptible to inhibition by first-generation NS5A inhibitors in comparison to wild-type replicons. The fluorobenzimidazole inhibitors have improved pharmacokinetic properties in comparison to non-fluorinated benzimidazole analogs. Discovery of these inhibitors was facilitated by exploring SAR in a structurally simplified inhibitor series.
Asunto(s)
Antivirales/química , Antivirales/farmacología , Bencimidazoles/química , Bencimidazoles/farmacología , Hepacivirus/efectos de los fármacos , Proteínas no Estructurales Virales/antagonistas & inhibidores , Animales , Antivirales/farmacocinética , Bencimidazoles/farmacocinética , Perros , Genotipo , Halogenación , Hepacivirus/genética , Hepacivirus/metabolismo , Hepatitis C/tratamiento farmacológico , Humanos , Ratones , Ratas , Replicón/efectos de los fármacos , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismoRESUMEN
Leucine is an essential branched-chain amino acid that acts as a substrate for protein synthesis and as a signaling molecule. Leucine not incorporated into muscle protein is ultimately oxidized through intermediates such as ß-hydroxy-ß-methylbutyrate (HMB) which itself is reported to enhance muscle mass and function in rats and humans. HMB has been reported in the plasma following oral leucine administration in sheep and pigs but not in Sprague-Dawley rats, the standard preclinical model. Therefore, we conducted radiolabeled absorption, distribution, metabolism and excretion (ADME) studies in rats using a low (3 mg/kg) or high dose (1,000 mg/kg) of (14)C-leucine. Blood, tissue, and urine samples were analyzed for (14)C-leucine and its metabolites by HPLC-MS. Our results show for the first time that (14)C-HMB appears in plasma and urine of rats following an oral dose of (14)C-leucine. (14)C-leucine appears in plasma as (14)C-α-ketoisocaproic acid (KIC) with a slower time course than (14)C-HMB, a putative product of KIC. Further, two novel metabolites of leucine were detected in urine, N-acetyl leucine and glycyl leucine. Mass balance studies demonstrate that excretory routes accounted for no more than 0.9 % of the radiolabel and approximately 61 % of the dose was recovered in the carcass. Approximately 65 % of the dose was recovered in total, suggesting that approximately one-third of the leucine dose is oxidized to CO2. In conclusion, this study demonstrates endogenous production of HMB from leucine in adult rats, a standard preclinical model used to guide design of clinical trials in nutrition.
Asunto(s)
Dipéptidos/orina , Cetoácidos/sangre , Leucina/análogos & derivados , Leucina/farmacocinética , Valeratos/sangre , Animales , Transporte Biológico , Radioisótopos de Carbono , Cromatografía Líquida de Alta Presión , Dipéptidos/sangre , Absorción Intestinal/fisiología , Cetoácidos/orina , Leucina/sangre , Leucina/orina , Masculino , Espectrometría de Masas , Oxidación-Reducción , Ratas , Ratas Sprague-Dawley , Valeratos/orinaRESUMEN
The synthesis and structure-activity relationships of a novel aryl uracil series which contains a fused 5,6-bicyclic ring unit for HCV NS5B inhibition is described. Several analogs display replicon cell culture potencies in the low nanomolar range along with excellent rat pharmacokinetic values.
Asunto(s)
Compuestos Bicíclicos con Puentes/química , Compuestos Bicíclicos con Puentes/farmacología , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Uracilo/antagonistas & inhibidores , Proteínas no Estructurales Virales/antagonistas & inhibidores , Animales , Compuestos Bicíclicos con Puentes/síntesis química , Compuestos Bicíclicos con Puentes/farmacocinética , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacocinética , Hepacivirus/enzimología , ARN Polimerasa Dependiente del ARN/antagonistas & inhibidores , ARN Polimerasa Dependiente del ARN/metabolismo , Ratas , Relación Estructura-Actividad , Uracilo/farmacología , Proteínas no Estructurales Virales/metabolismoRESUMEN
A series of quinoline derivatives was synthesized as potential bioisosteric replacements for the benzothiadiazine moiety of earlier Hepatitis C NS5B polymerase inhibitors. Several of these compounds exhibited potent activity in enzymatic and replicon assays.
Asunto(s)
Benzotiadiazinas/farmacología , Inhibidores de Proteasas/farmacología , Proteínas no Estructurales Virales/antagonistas & inhibidores , Benzotiadiazinas/química , Hepacivirus/enzimología , Hepacivirus/fisiología , Inhibidores de Proteasas/química , Replicación ViralRESUMEN
A highly potent and selective DGAT-1 inhibitor was identified and used in rodent models of obesity and postprandial chylomicron excursion to validate DGAT-1 inhibition as a novel approach for the treatment of metabolic diseases. Specifically, compound 4a conferred weight loss and a reduction in liver triglycerides when dosed chronically in DIO mice and depleted serum triglycerides following a lipid challenge in a dose-dependent manner, thus, reproducing major phenotypical characteristics of DGAT-1(-/-) mice.
Asunto(s)
Fármacos Antiobesidad/síntesis química , Cicloheptanos/síntesis química , Diacilglicerol O-Acetiltransferasa/antagonistas & inhibidores , Hipolipemiantes/síntesis química , Cetoácidos/síntesis química , Urea/análogos & derivados , Urea/síntesis química , Animales , Fármacos Antiobesidad/farmacocinética , Fármacos Antiobesidad/farmacología , Compuestos de Bifenilo/síntesis química , Compuestos de Bifenilo/farmacocinética , Compuestos de Bifenilo/farmacología , Cicloheptanos/farmacocinética , Cicloheptanos/farmacología , Diacilglicerol O-Acetiltransferasa/genética , Ingestión de Alimentos/efectos de los fármacos , Humanos , Hipolipemiantes/farmacocinética , Hipolipemiantes/farmacología , Isoenzimas/antagonistas & inhibidores , Isoenzimas/genética , Cetoácidos/farmacocinética , Cetoácidos/farmacología , Hígado/metabolismo , Ratones , Ratones Mutantes , Estereoisomerismo , Relación Estructura-Actividad , Triglicéridos/metabolismo , Urea/farmacocinética , Urea/farmacología , Pérdida de PesoRESUMEN
4,4-Dialkyl-1-hydroxy-3-oxo-3.4-dihydronaphthalene-3-yl benzothiadiazine derivatives were synthesized and evaluated as inhibitors of genotypes 1a and 1b HCV NS5B polymerase. A number of these compounds exhibited potent activity against genotypes 1a and 1b HCV polymerase in both enzymatic and cell culture activities. A representative compound also showed favorable pharmacokinetics in the rat.
Asunto(s)
Antivirales/síntesis química , Antivirales/farmacocinética , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacocinética , Proteínas no Estructurales Virales/antagonistas & inhibidores , Administración Oral , Animales , Área Bajo la Curva , Química Farmacéutica/métodos , Diseño de Fármacos , Genotipo , Infusiones Intravenosas , Concentración 50 Inhibidora , Modelos Químicos , Ratas , Proteínas no Estructurales Virales/genéticaRESUMEN
ABT-072 is a non-nucleoside HCV NS5B polymerase inhibitor that was discovered as part of a program to identify new direct-acting antivirals (DAAs) for the treatment of HCV infection. This compound was identified during a medicinal chemistry effort to improve on an original lead, inhibitor 1, which we described in a previous publication. Replacement of the amide linkage in 1 with a trans-olefin resulted in improved compound permeability and solubility and provided much better pharmacokinetic properties in preclinical species. Replacement of the dihydrouracil in 1 with an N-linked uracil provided better potency in the genotype 1 replicon assay. Results from phase 1 clinical studies supported once-daily oral dosing with ABT-072 in HCV infected patients. A phase 2 clinical study that combined ABT-072 with the HCV protease inhibitor ABT-450 provided a sustained virologic response at 24 weeks after dosing (SVR24) in 10 of 11 patients who received treatment.
Asunto(s)
Citosina/análogos & derivados , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Hepacivirus/enzimología , Estilbenos/química , Sulfonamidas/síntesis química , Sulfonamidas/farmacología , Proteínas no Estructurales Virales/antagonistas & inhibidores , Administración Oral , Disponibilidad Biológica , Técnicas de Química Sintética , Citosina/síntesis química , Citosina/química , Citosina/farmacocinética , Citosina/farmacología , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacocinética , Humanos , Permeabilidad , Estereoisomerismo , Sulfonamidas/química , Sulfonamidas/farmacocinética , Distribución Tisular , Proteínas no Estructurales Virales/químicaRESUMEN
Dipeptidyl peptidase IV (DPP4) inhibitors are emerging as a new class of therapeutic agents for the treatment of type 2 diabetes. They exert their beneficial effects by increasing the levels of active glucagon-like peptide-1 and glucose-dependent insulinotropic peptide, which are two important incretins for glucose homeostasis. Starting from a high-throughput screening hit, we were able to identify a series of piperidinone- and piperidine-constrained phenethylamines as novel DPP4 inhibitors. Optimized compounds are potent, selective, and have good pharmacokinetic profiles.
Asunto(s)
Inhibidores de la Adenosina Desaminasa , Inhibidores de la Dipeptidil-Peptidasa IV , Glicoproteínas/antagonistas & inhibidores , Fenetilaminas/síntesis química , Piperidinas/síntesis química , Animales , Disponibilidad Biológica , Cristalografía por Rayos X , Dipeptidil Peptidasa 4 , Humanos , Conformación Molecular , Fenetilaminas/farmacocinética , Fenetilaminas/farmacología , Piperidinas/farmacocinética , Piperidinas/farmacología , Piperidonas/síntesis química , Piperidonas/farmacocinética , Piperidonas/farmacología , Ratas , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
A preliminary safety evaluation of ACC2 inhibitor 1-(S) revealed serious neurological and cardiovascular liabilities of this chemotype. A systematic structure-toxicity relationship study identified the alkyne linker as the key motif responsible for these adverse effects. Toxicogenomic studies in rats showed that 1-(R) and 1-(S) induced gene expression patterns similar to that seen with several known cardiotoxic agents such as doxorubicin. Replacement of the alkyne with alternative linker groups led to a new series of ACC inhibitors with drastically improved cardiovascular and neurological profiles.
Asunto(s)
Acetil-CoA Carboxilasa/antagonistas & inhibidores , Presión Sanguínea/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Convulsiones/inducido químicamente , Tiazoles/síntesis química , Administración Oral , Animales , Expresión Génica/efectos de los fármacos , Infusiones Intravenosas , Masculino , Miocardio/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , Ratas , Ratas Sprague-Dawley , Estereoisomerismo , Relación Estructura-Actividad , Tiazoles/efectos adversos , Tiazoles/químicaRESUMEN
Starting from a rapidly metabolized adamantane 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) inhibitor 22a, a series of E-5-hydroxy-2-adamantamine inhibitors, exemplified by 22d and (+/-)-22f, was discovered. Many of these compounds are potent inhibitors of 11beta-HSD1 and are selective over 11beta-HSD2 for multiple species (human, mouse, and rat), unlike other reported species-selective series. These compounds have good cellular potency and improved microsomal stability. Pharmacokinetic profiling in rodents indicated moderate to large volumes of distribution, short half-lives, and a pharmacokinetic species difference with the greatest exposure measured in rat with 22d. One hour postdose liver, adipose, and brain tissue 11beta-HSD1 inhibition was confirmed with (+/-)-22f in a murine ex vivo assay. Although 5,7-disubstitued-2-adamantamines provided greater stability, a single, E-5-position, polar functional group afforded inhibitors with the best combination of stability, potency, and selectivity. These results indicate that adamantane metabolic stabilization sufficient to obtain short-acting, potent, and selective 11beta-HSD1 inhibitors has been discovered.
Asunto(s)
11-beta-Hidroxiesteroide Deshidrogenasa de Tipo 1/antagonistas & inhibidores , Adamantano/análogos & derivados , Adamantano/síntesis química , Piperazinas/síntesis química , 11-beta-Hidroxiesteroide Deshidrogenasa de Tipo 1/genética , Adamantano/farmacocinética , Animales , Línea Celular , Humanos , Técnicas In Vitro , Ratones , Microsomas Hepáticos/metabolismo , Piperazinas/farmacocinética , Ratas , Estereoisomerismo , Relación Estructura-Actividad , Distribución TisularRESUMEN
Stearoyl-CoA desaturase 1 (SCD1) catalyzes the committed step in the biosynthesis of monounsaturated fatty acids from saturated, long-chain fatty acids. Studies with SCD1 knockout mice have established that these animals are lean and protected from leptin deficiency-induced and diet-induced obesity, with greater whole body insulin sensitivity than wild-type animals. In this work, we have discovered a series of potent, selective, orally bioavailable SCD1 inhibitors based on a known pyridazine carboxamide template. The representative lead inhibitor 28c also demonstrates excellent cellular activity in blocking the conversion of saturated long-chain fatty acid-CoAs (LCFA-CoAs) to monounsaturated LCFA-CoAs in HepG2 cells.
Asunto(s)
Oxadiazoles/síntesis química , Piridazinas/síntesis química , Estearoil-CoA Desaturasa/antagonistas & inhibidores , Acilcoenzima A/metabolismo , Animales , Disponibilidad Biológica , Línea Celular Tumoral , Humanos , Técnicas In Vitro , Ratones , Microsomas Hepáticos/metabolismo , Oxadiazoles/farmacocinética , Oxadiazoles/farmacología , Piridazinas/farmacocinética , Piridazinas/farmacología , Ratas , Ratas Sprague-Dawley , Relación Estructura-ActividadRESUMEN
Ghrelin, a gut-derived orexigenic hormone, is an endogenous ligand of the growth hormone secretagogue receptor (GHS-R). Centrally administered ghrelin has been shown to cause hunger and increase food intake in rodents. Inhibition of ghrelin actions with ghrelin antibody, peptidyl GHS-R antagonists, and antisense oligonucleosides resulted in weight loss and food intake decrease in rodents. Here we report the effects of GHS-R antagonists, some of which were potent, selective, and orally bioavailable. A structure-activity relationship study led to the discovery of 8a, which was effective in decreasing food intake and body weight in several acute rat studies.
Asunto(s)
Pirimidinas/farmacología , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Animales , Células CHO , Cricetinae , Evaluación Preclínica de Medicamentos , Humanos , Ligandos , Estructura Molecular , Pirimidinas/síntesis química , Pirimidinas/química , Receptores de Ghrelina , Estereoisomerismo , Relación Estructura-Actividad , Factores de TiempoRESUMEN
Dipeptidyl peptidase IV (DPP4) deactivates glucose-regulating hormones such as GLP-1 and GIP, thus, DPP4 inhibition has become a useful therapy for type 2 diabetes. Optimization of the high-throughput screening lead 6 led to the discovery of 25 (ABT-341), a highly potent, selective, and orally bioavailable DPP4 inhibitor. When dosed orally, 25 dose-dependently reduced glucose excursion in ZDF rats. Amide 25 is safe in a battery of in vitro and in vivo tests and may represent a new therapeutic agent for the treatment of type 2 diabetes.
Asunto(s)
Compuestos de Bifenilo/farmacología , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Dipeptidil Peptidasa 4/metabolismo , Hipoglucemiantes/farmacología , Inhibidores de Serina Proteinasa/farmacología , Triazoles/farmacología , Animales , Compuestos de Bifenilo/síntesis química , Compuestos de Bifenilo/farmacocinética , Ciclohexenos/química , Diabetes Mellitus Tipo 2/genética , Relación Dosis-Respuesta a Droga , Diseño de Fármacos , Evaluación Preclínica de Medicamentos , Femenino , Hipoglucemiantes/síntesis química , Hipoglucemiantes/farmacocinética , Modelos Moleculares , Ratas , Ratas Zucker , Inhibidores de Serina Proteinasa/síntesis química , Inhibidores de Serina Proteinasa/farmacocinética , Relación Estructura-Actividad , Triazoles/síntesis química , Triazoles/farmacocinética , Difracción de Rayos XRESUMEN
A series of (5-substituted pyrrolidinyl-2-carbonyl)-2-cyanopyrrolidine (C5-Pro-Pro) analogues was discovered as dipeptidyl peptidase IV (DPPIV) inhibitors as a potential treatment of diabetes and obesity. X-ray crystallography data show that these inhibitors bind to the catalytic site of DPPIV with the cyano group forming a covalent bond with the serine residue of DPPIV. The C5-substituents make various interactions with the enzyme and affect potency, chemical stability, selectivity, and PK properties of the inhibitors. Optimized analogues are extremely potent with subnanomolar K(i)'s, are chemically stable, show very little potency decrease in the presence of plasma, and exhibit more than 1,000-fold selectivity against related peptidases. The best compounds also possess good PK and are efficacious in lowering blood glucose in an oral glucose tolerance test in ZDF rats.
Asunto(s)
Fármacos Antiobesidad/síntesis química , Dipeptidil Peptidasa 4/metabolismo , Hipoglucemiantes/síntesis química , Nitrilos/síntesis química , Inhibidores de Proteasas/síntesis química , Pirrolidinas/síntesis química , Animales , Fármacos Antiobesidad/farmacocinética , Fármacos Antiobesidad/farmacología , Glucemia/análisis , Dominio Catalítico , Cristalografía por Rayos X , Estabilidad de Medicamentos , Prueba de Tolerancia a la Glucosa , Humanos , Hipoglucemiantes/farmacocinética , Hipoglucemiantes/farmacología , Modelos Moleculares , Nitrilos/farmacocinética , Nitrilos/farmacología , Inhibidores de Proteasas/farmacocinética , Inhibidores de Proteasas/farmacología , Pirrolidinas/farmacocinética , Pirrolidinas/farmacología , Ratas , Ratas Sprague-Dawley , Ratas Zucker , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
The discovery and pharmacological evaluation of potent, selective, and orally bioavailable growth hormone secretagogue receptor (GHS-R) antagonists are reported. Previously, 2,4-diaminopyrimidine-based GHS-R antagonists reported from our laboratories have been shown to be dihydrofolate reductase (DHFR) inhibitors. By comparing the X-ray crystal structure of DHFR docked with our GHS-R antagonists and GHS-R modeling, we designed and synthesized a series of potent and DHFR selective GHS-R antagonists with good pharmacokinetic (PK) profiles. An amide derivative 13d (Ca2+ flux IC50 = 188 nM, [brain]/[plasma] = 0.97 @ 8 h in rat) showed a 10% decrease in 24 h food intake in rats, and over 5% body weight reduction after 14-day oral treatment in diet-induced obese (DIO) mice. In comparison, a urea derivative 14c (Ca2+ flux IC50 = 7 nM, [brain]/[plasma] = 0.0 in DIO) failed to show significant effect on food intake in the acute feeding DIO model. These observations demonstrated for the first time that peripheral GHS-R blockage with small molecule GHS-R antagonists might not be sufficient for suppressing appetite and inducing body weight reduction.
Asunto(s)
Aminopiridinas/síntesis química , Fármacos Antiobesidad/síntesis química , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Administración Oral , Amidas/síntesis química , Amidas/farmacología , Aminopiridinas/farmacología , Animales , Fármacos Antiobesidad/farmacología , Depresores del Apetito/síntesis química , Depresores del Apetito/farmacología , Disponibilidad Biológica , Peso Corporal/efectos de los fármacos , Línea Celular , Cristalografía por Rayos X , Ingestión de Alimentos/efectos de los fármacos , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Obesos , Modelos Moleculares , Estructura Molecular , Ratas , Ratas Sprague-Dawley , Receptores de Ghrelina , Relación Estructura-Actividad , Urea/análogos & derivados , Urea/síntesis química , Urea/farmacologíaRESUMEN
Dipeptidyl peptidase-IV (DPP-IV) inhibitors are poised to be the next major drug class for the treatment of type 2 diabetes. Structure-activity studies of substitutions at the C5 position of the 2-cyanopyrrolidide warhead led to the discovery of potent inhibitors of DPP-IV that lack activity against DPP8 and DPP9. Further modification led to an extremely potent (Ki(DPP)(-)(IV) = 1.0 nM) and selective (Ki(DPP8) > 30 microM; Ki(DPP9) > 30 microM) clinical candidate, ABT-279, that is orally available, efficacious, and remarkably safe in preclinical safety studies.
Asunto(s)
Inhibidores de la Adenosina Desaminasa , Inhibidores de la Dipeptidil-Peptidasa IV , Glicoproteínas/antagonistas & inhibidores , Hipoglucemiantes/síntesis química , Piridinas/síntesis química , Pirrolidinas/síntesis química , Adenosina Desaminasa/química , Administración Oral , Animales , Sitios de Unión , Células CACO-2 , Cristalografía por Rayos X , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Dipeptidil Peptidasa 4/química , Perros , Femenino , Intolerancia a la Glucosa/tratamiento farmacológico , Glicoproteínas/química , Humanos , Hipoglucemiantes/farmacocinética , Hipoglucemiantes/farmacología , Macaca fascicularis , Modelos Moleculares , Estructura Molecular , Piridinas/farmacocinética , Piridinas/farmacología , Pirrolidinas/farmacocinética , Pirrolidinas/farmacología , Ratas , Ratas Sprague-Dawley , Ratas Zucker , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
The mechanism of liver injury in endotoxemia is unclear. Previous studies have shown that splenectomy protects the liver from endotoxin-induced injury. The purpose of this study was to determine the relationship of TNFalpha and IFNgamma release and endotoxin-induced liver injury in splenectomized and nonsplenectomized rats. Splenectomized and nonsplenectomized (Sham) rats with chronic catheters in the aorta and inferior vena cava (IVC) were parenterally infused with 10 to 5000 microg/kg endotoxin. TNFalpha, IFNgamma, and alanine aminotransferase (ALT), a marker of hepatocellular damage, were measured in aortic blood. Compared to sham controls, splenectomized animals demonstrated significantly reduced endotoxin-induced ALT concentrations at endotoxin doses >10 microg/kg. Peak endotoxin-induced TNFalpha concentrations were not significantly different between the splenectomized and sham groups. In contrast, peak endotoxin-induced IFNgamma concentrations were significantly decreased in the splenectomized group. These data suggest a relationship between endotoxin-induced IFNgamma and liver injury. We speculate that the spleen contributes to the endotoxin-induced liver injury by modulating release of IFNgamma.
Asunto(s)
Endotoxinas/toxicidad , Interferón gamma/biosíntesis , Hígado/efectos de los fármacos , Hígado/lesiones , Bazo/fisiología , Alanina Transaminasa/sangre , Animales , Interferón gamma/sangre , Hígado/fisiopatología , Masculino , Ratas , Ratas Sprague-Dawley , Esplenectomía , Factor de Necrosis Tumoral alfa/biosíntesisRESUMEN
We have previously shown that systemic infusion of the bacterial toxins Staphylococcal enterotoxin B (SEB) and endotoxin (LPS) induces hepatic dysfunction as measured by decreased biliary indocyanine green (ICG) excretion. In this study, we compare the effects of these bacterial toxins after infusion into the portal and systemic circulation and directly measure biliary bile acid excretion as a measure of cholestasis. We hypothesized that bacterial toxins infused into the portal vein would induce greater hepatic dysfunction than toxins infused into the systemic circulation. Using a chronically catheterized rat model, biliary bile acid excretion was directly measured after infusion of LPS at 10 and 100 microg/kg with and without 50 microg/kg SEB into the portal vein (IPV) or inferior vena cava (IV) at baseline, and at 6 and 24 h. We found that when LPS was infused alone, only IPV administration caused a significant decrease in bile acid excretion at 6 h. There was no change in bile acid excretion after IV administration of LPS. In contrast, when the combination of LPS and SEB was infused, both IV and IPV administration significantly decreased bile acid excretion at 6 and 24 h. At 6 h post-LPS and -SEB administration, the decrease in bile acid excretion was significantly greater after IPV than IV administration. There was no site-specific difference in IFN-gamma release after infusion of toxins. However, peak TNFalpha release was decreased in IPV-infused rats [10 microg/kg (P < 0.05) or 100 microg/kg (P = ns) LPS with SEB] compared with the same doses in IV-infused rats. These data question the role of systemic TNF-alpha and IFN-gamma in regulating hepatic dysfunction and suggest a differential functional response of the liver to systemic and gut-derived septic events. This study also further explains the frequent development of liver dysfunction in patients with sepsis, multisystem organ failure, and other diseases with altered intestinal permeability.
Asunto(s)
Enfermedad Hepática Inducida por Sustancias y Drogas , Endotoxinas/toxicidad , Enterotoxinas/toxicidad , Animales , Bilis/química , Ácidos y Sales Biliares/análisis , Ácidos y Sales Biliares/sangre , Ácidos y Sales Biliares/metabolismo , Endotoxinas/administración & dosificación , Enterotoxinas/administración & dosificación , Inyecciones Intravenosas , Masculino , Vena Porta , Ratas , Ratas Sprague-Dawley , Vena Cava InferiorRESUMEN
Recent studies suggest that prostaglandin E may have the ability to suppress cytokine responsiveness. We examined the effects of prostaglandin E administration on several parameters of the acute and chronic hepatic injury induced by bile duct ligation. Enisoprost, a prostaglandin E(1) analog was found to suppress early hepatic and Ito cell type I collagen gene expression without diminishing the induction of the fibrogenic cytokine, transforming growth factor beta. Overall hepatic inflammation and cell proliferation were not altered, suggesting that prostaglandin E acts distal to the initial injurious event(s). During the later phases, drug administration reduced total collagen accumulation as well as type I collagen periductular infiltration associated with early nodule formation. Ito cell mitogenesis occurs during liver injury and fibrogenesis in vivo coincident with the de novo expression of Ito cell platelet-derived growth factor beta (PDGFbeta) receptor messenger RNA. PDGF-induced mitogenesis was studied in cultured rat hepatic Ito cells which resemble the myofibroblast associated with liver injury. Pretreatment with prostaglandin E markedly suppressed the PDGF response in a dose-dependent fashion. The PDGF-induced cascade was studied plus minus PGE to determine the level of regulation which induced the observed suppression. PGE caused no apparent diminution in the abundance of the surface PDGFbeta receptor nor its subsequent activation and tyrosine phosphorylation following PDGF stimulation. The cytoplasmic "secondary messengers" mitogen-activated protein kinase pp42--44 and raf kinase appeared to be comparably induced and therefore unaffected by PGE. Raf perinuclear translocation was also intact, and comparable degrees of nuclear egr, fos, and jun expression occurred. Because other studies have suggested that many of these features of the PDGF cascade may be causally and sequentially linked, the data collectively suggest that the dominant PGE mitogenic suppressive effect resides at a Raf-MAP parallel pathway or at a nuclear level distal to the induction of these early growth response genes.
RESUMEN
We describe here N-phenylpyrrolidine-based inhibitors of HCV NS5A with excellent potency, metabolic stability, and pharmacokinetics. Compounds with 2S,5S stereochemistry at the pyrrolidine ring provided improved genotype 1 (GT1) potency compared to the 2R,5R analogues. Furthermore, the attachment of substituents at the 4-position of the central N-phenyl group resulted in compounds with improved potency. Substitution with tert-butyl, as in compound 38 (ABT-267), provided compounds with low-picomolar EC50 values and superior pharmacokinetics. It was discovered that compound 38 was a pan-genotypic HCV inhibitor, with an EC50 range of 1.7-19.3 pM against GT1a, -1b, -2a, -2b, -3a, -4a, and -5a and 366 pM against GT6a. Compound 38 decreased HCV RNA up to 3.10 log10 IU/mL during 3-day monotherapy in treatment-naive HCV GT1-infected subjects and is currently in phase 3 clinical trials in combination with an NS3 protease inhibitor with ritonavir (r) (ABT-450/r) and an NS5B non-nucleoside polymerase inhibitor (ABT-333), with and without ribavirin.