Evaluation of micro RNA profile and expression of genes related to oxidative stress and inflammatory response in septic patients' microparticles

Abstract

Sepsis' pathogenesis is characterized by exacerbated inflammatory response and increased production of reactive oxygen species (ROS). ROS may be released by circulating microparticles produced upon activation of several cell types. We previously demonstrated the presence of a subtype of microparticles (exosomes) in the circulation of septic shock patients. Exosomes may induce apoptosis in cultured vascular cells and myocardial dysfunction ex vivo. Studies have also shown that these microparticles carry on messenger RNA (RNAm) and micro RNA (miRNA), thus indicating that they may act as transmitters of distant cell signaling. However, the importance of this mechanism during sepsis has not been evaluated. This study aims to analyze the pattern of global miRNA expression and the presence of genes related to oxidative stress and inflammatory response in microparticles isolated from sepsis patients. Our objective is to compare these results with normal volunteers and to correlate our findings with the disease severity and organ failure. Blood (20 ml) will be collected from 40 patients with septic shock in the first 48 hours of sepsis and, for the survivors, after 7 days. Twenty volunteers will serve as controls. After isolation of microparticles, their miRNA and mRNA contents will be evaluated by real time polymerase chain reaction (qPCR). For evaluation of global miRNA expression by qPCR, the TaqMan MicroRNA Array will be used. Inflammatory response will be screened by the kit Human Immune Array (Applied Biosystems) and oxidative stress by the kit Human Oxidative Stress and Antioxidant Defense Array (SABiosciences). (AU)