RESUMO
Thioredoxin is one of the most important cellular antioxidant systems known to date, and is responsible of maintaining the reduced state of the intracellular space. Trx-1 is a small cytosolic protein whose transcription is induced by stress. Therefore it is possible that this antioxidant plays a protective role against the oxidative stress caused by an increase of reactive oxygen species concentration, as occurs during the reperfusion after an ischemic episode. However, in addition to its antioxidant properties, it is able to activate other cytoplasmic and nuclear mediators that confer cardioprotection. It is remarkable that Trx-1 also participates in myocardial protection mechanisms such as ischemic preconditioning and postconditioning, activating proteins related to cellular survival. In this sense, it has been shown that Trx-1 inhibition abolished the preconditioning cardioprotective effect, evidenced through apoptosis and infarct size. Furthermore, ischemic postconditioning preserves Trx-1 content at reperfusion, after ischemia. However, comorbidities such as aging can modify this powerful cellular defense leading to decrease cardioprotection. Even ischemic preconditioning and postconditioning protocols performed in aged animal models failed to decrease infarct size. Therefore, the lack of success of antioxidants therapies to treat ischemic heart disease could be solved, at least in part, avoiding the damage of Trx system.
Assuntos
Pós-Condicionamento Isquêmico , Precondicionamento Isquêmico , Traumatismo por Reperfusão Miocárdica/metabolismo , Tiorredoxinas/metabolismo , Envelhecimento/metabolismo , Envelhecimento/fisiologia , Animais , Vasos Coronários/fisiologia , Coração/fisiopatologia , Humanos , Miocárdio/metabolismo , Tiorredoxinas/fisiologiaRESUMO
The different theories about the mechanisms involved in the development of metabolic disease and its complications converge in the presence of an etiologic chronic proinflammatory state. Chronic inflammation is, at present, the central pathophysiological mechanism involved in the genesis of metabolic diseases. The multiple interactions between the immune system, adipose tissue, the vascular wall and the pancreas are the issues addressed in this review, focusing on specific intracellular and molecular aspects that may become new therapeutic targets. These lead to a proinflammatory, prothrombotic state as well as to proapoptotic endothelial damage that allows the development of atherosclerosis and, consequently, cardiovascular disease. The multiple immunopathological processes associated with the etiology and pathophysiology of different chronic diseases is still in the process of being fully elucidated, allowing the development of new therapeutic targets.