RESUMO
Exposure to moderately selective p38alpha mitogen-activated protein kinase (MAPK) inhibitors in the Beagle dog results in an acute toxicity consisting of mild clinical signs (decreased activity, diarrhea, and fever), lymphoid necrosis and depletion in the gut-associated lymphoid tissue (GALT), mesenteric lymph nodes and spleen, and linear colonic and cecal mucosal hemorrhages. Lymphocyte apoptosis and necrosis in the GALT is the earliest and most prominent histopathologic change observed, followed temporally by neutrophilic infiltration and acute inflammation of the lymph nodes and spleen and multifocal mucosal epithelial necrosis and linear hemorrhages in the colon and cecum. These effects are not observed in the mouse, rat, or cynomolgus monkey. To further characterize the acute toxicity in the dog, a series of in vivo, in vitro, and immunohistochemical studies were conducted to determine the relationship between the lymphoid and gastrointestinal (GI) toxicity and p38 MAPK inhibition. Results of these studies demonstrate a direct correlation between p38alpha MAPK inhibition and the acute lymphoid and gastrointestinal toxicity in the dog. Similar effects were observed following exposure to inhibitors of MAPK-activated protein kinase-2 (MK2), further implicating the role of p38alpha MAPK signaling pathway inhibition in these effects. Based on these findings, the authors conclude that p38alpha MAPK inhibition results in acute lymphoid and GI toxicity in the dog and is unique among the species evaluated in these studies.
Assuntos
Gastroenteropatias/induzido quimicamente , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Doenças Linfáticas/induzido quimicamente , Inibidores de Proteínas Quinases/toxicidade , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores , Animais , Linfócitos B/metabolismo , Western Blotting , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Colo/efeitos dos fármacos , Colo/patologia , Cães , Feminino , Gastroenteropatias/patologia , Hemorragia Gastrointestinal/induzido quimicamente , Humanos , Imuno-Histoquímica , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Modelos Lineares , Linfonodos/efeitos dos fármacos , Linfonodos/patologia , Doenças Linfáticas/patologia , Macaca fascicularis , Masculino , Camundongos , Proteínas Serina-Treonina Quinases/metabolismo , Ratos , Ratos Sprague-Dawley , Baço/citologia , Baço/metabolismo , Linfócitos T/metabolismo , Testes de Toxicidade Aguda , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Relationships between physicochemical drug properties and toxicity were inferred from a data set consisting of animal in vivo toleration (IVT) studies on 245 preclinical Pfizer compounds; an increased likelihood of toxic events was found for less polar, more lipophilic compounds. This trend held across a wide range of types of toxicity and across a broad swath of chemical space.
