Controlling the Source of Inflammatory Signaling in a Burn Model

摘要

Abstract Severe thermal insult induces a major disturbance in homeostatic and regulatory mechanisms. Since an aberrant systemic inflammatory activation appears to be the underlying mechanism for ultimate organ failure, most studies have focused on systemic modulation of this over-exuberant immune response. However, systemic administration of several anti-inflammatory or immunomodulatory agents has failed to demonstrate improvement in survival or organ failure in various conditions. In addition, since these agents are not tissue specific and act on multiple organs, systemic administration may have unpredictable deleterious results in a complex interacting system of cell-specific pathways. We therefore have focused on a novel approach which calls for "inflammatory source control". We have demonstrated that there is a strong interaction between the local-dermal and systemic inflammatory response; hence, controlling the local inflammatory signaling at the burn wound would attenuate the subsequent complications such as acute lung injury. The over arching hypothesis for this application is that the burn-wound inflammatory stress shielding with topical immunomodulation attenuates systemic inflammatory activation and end-organ dysfunction, whereas systemic administration of the same immunomodulators will have unpredictable results. In a post burn injury model, we will investigate the interaction between dermal and systemic inflammatory response by topical administration of inhibitors of intracellular stress signaling to the burn wound. The agents used are inhibitors of p38 and c-Jun N- terminal kinase (JNK), which are recognized as mitogen-activated protein kinases that are activated in response to physiological stress. We will compare topical application of these immunomodulators to post-burn systemic administration. We further hypothesize that topical inhibition of the inflammatory signaling does not affect the innate immune system's ability to resist subsequent bacterial infections, while systemic administration will interfere with the normal immune response. Thus this proposal sets out to elucidate the mechanisms responsible for the activation of systemic inflammatory response after a large thermal insult and the potential therapeutic approach by topical application of immunomodulators post-burn. Understanding the interaction between local and subsequent systemic inflammatory response in this model may be applicable to other pathophysiological systems, which are initiated by a more localized inflammatory stimulus. Furthermore, topical burn-wound inhibition of inflammatory signaling as an experimental strategy for inhibition of end-organ injury is a promising therapy that is practical and fits the current clinical practice of daily application of topical antimicrobial agents. This topical treatment is easy to apply and can be initiated early post injury, even at the scene.