Septic shock is a systemic inflammatory response syndrome associated with circulation failure leading to organ failure with a mortality rate of 40%. Early diagnosis and prognosis of septic shock are necessary for timely and specific treatment but no predictive biomarkers are available. The plasma proteome is easily accessible and may contain biomarkers that can be studied with non-targeted “omic” strategies.

We aim to decipher a relevant proteome signature through a non-targeted mass spectrometry (MS) analysis in a rat septic shock model.

In 10-week-old Wistar rats (n=11/group), 30min post-buprenorphine (0.05mg/kg, s) endotoxemic shock was induced by lipopolysaccharides injection (LPS, S. enterica typhi, 0.5mg/kg, iv) and compared to controls (NaCl 0.9%, iv). Under isoflurane anesthesia, carotid cannulation allowed mean arterial blood pressure (MAP), heart rate (HR) monitoring and blood sampling (T0, 50 and 150 min-EDTA with protease inhibitor). Each plasma was prepared for RPHPLC/MS by performing Proteominer, dialysis and trypsin digestion. RPHPLC-MS analysis was performed on a ESI-Q-Exactive mass spectrometer (ThermoFisher) according to a non-targeted label-free MS analysis. Data were analyzed with PEAKS and R software.

LPS group present circulation failure (−40% MAP, +20% of HR vs Ctrl, P<0.05) and an increase in lactate levels (LPS: 6.00±0.86mM, Ctrl: 1.70±0.26mM, P<0.05). Proteomic analyses revealed 106 deregulated (21 down and 80 up-regulated) proteins with LPS. The interactome map highlighted pathways involved, as vascular homeostasis or stress responses. Some of these proteins have already been described in human septic proteome signature, demonstrating the relevance of this approach.

This preliminary study revealed propose a new approach to identify relevant deregulated proteins in septic shock. The investigation of the link between our results and patients’ clinical features is in progress.