Proteomics in sepsis: a pilot study - Critical Care Science (CCS)

Gene expression is disrupted by sepsis. Genetic markers can only reveal a patient’s genotype, and they are not affected by environmental biological processes. These processes are expressed by proteins. This study was aimed to advance the insight into the molecular foundations of sepsis. It employed proteomic techniques to identify and analyze differential serum protein expressions taken from a patient throughout the stages of sepsis (sepsis, severe sepsis and septic shock). Serum samples were collected at each stage of sepsis and submitted to one-dimensional electrophoresis, on gradient strips of immobilized pH, followed by two-dimensional 12.5% polyacrylamide gel electrophoresis. The gels obtained were stained, scanned and analyzed by the ImageMasterPlatinum program. Proteins that were differentially expressed in the gels were excised, digested with trypsin and identified through mass spectrometry. Fourteen differentially expressed proteins were identified throughout the stages of sepsis, as well as a protein that was not expressed in all stages, suggesting the potential existence of a biomarker. The differentially expressed proteins identified were: serum amyloid A, apolipoprotein A-1 (2 isoforms), zinc finger protein 222, human albumin, PRO 2619, immunoglobulin kappa light chain VLJ region, monoclonal immunoglobulin M cold agglutinin, 7 proteinase inhibitors – alpha-1 antitrypsin. The findings of this pilot study demonstrate the involvement of the complement and coagulation pathways, of the lipid metabolism and of genetic information in sepsis. The vast majority of proteins identified are involved in the immune system and the proteinase inhibitor proteins are predominant.