Avaliação do potencial terapêutico e estudo da atividade imunomodulatória e antimicrobiana in vitro e in vivo de diferentes formas de clavaninas

Abstract

Healthcare-associated infections (HAIs) are a major cause of mortality, also increasing hospital costs in developed and developing countries. When a patient acquires HAIs and this is not properly handled, disease may clearly worst, leading to sepsis and consequently in major to death. Despite of sepsis represents an important public health problem, any effective treatment for this syndrome was obtained until now. In this view, antimicrobial peptides have been reported as modulators of immune response to bacterial infection in sepsis, with independent activity of mechanisms that lead to antibiotic. Thus, the immunomodulatory activity of two different forms of clavanins over RAW 264.7 monocytes, as well the in vitro antimicrobial and cytotoxic activities were here investigated. Furthermore, in vivo genotoxicity assays, the evaluation of clavanins activity on neutrophil migration and also the efficacy of treatment with clavanins in a wound S. aureus infection model and severe polymicrobial sepsis were also evaluated. Moreover, in vitro studies demonstrated that clavanins are able of inhibit the growth of E. coli, K. pneumoniae and S. aureus. Clavanins also prevented the secretion of proinflammatory cytokines (TNF-α, IL-12) and NO, and increased the IL-10secretion. In addition, clavanins showed none cytotoxicity on RAW 264.7 cells. During in vivo experiments, the clavanins showed no genotoxicity, showing however, a clear chemotactic effect for neutrophils. Clavanins also significantly reduced the colony-forming units of S. aureus in an experimental model of surgical wound infection and reduced the mortality of septic animals in more than 50 %, when compared to control group. Due to their direct activities over immune cells and microorganisms, clavanins are potential compounds for the treatment of serious bacterial infections such as sepsis, showing an enormous and remarkable biotechnological value.