Differential diagnosis of systemic inflammation versus sepsis is based primarily on clinical criteria and laboratory tests that lack the required sensitivity and specificity. This dilemma holds true for medical as well as surgical patients, for example after bypass surgery or autoimmune disease. Both populations are characterized by the presence of signs of systemic inflammation or by increased risk for nosocomial infection and, thus, reflect patient populations at risk for sepsis with significant diagnostic uncertainty. Novel and robust biomarkers are urgently needed to correctly and timely identify infection as the underlying cause of a systemic host response because each hour of delay of anti-infectious therapy leads to increased mortality.

HomeCirculationVol. 113, No. 19Response to Letter Regarding Article by Tomic et al, "Transcriptomic and Proteomic Patterns of Systemic Inflammation in On-Pump and Off-Pump Coronary Artery Bypass Grafting" Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBResponse to Letter Regarding Article by Tomic et al, "Transcriptomic and Proteomic Patterns of Systemic Inflammation in On-Pump and Off-Pump Coronary Artery Bypass Grafting" V. Tomic, MD, S. Rußwurm, MD, R.A. Claus, PhD, F.M. Brunkhorst, MD, K. Bode, BS, F. Bloos, MD, PhD, K. Reinhart, MD and M. Bauer, MD E. Möller, PhD, M. Blaess, BS and H.-P. Deigner, PhD M. Bruegel, MD and J. Thiery, MD J. Wippermann, MD and T. Wahlers, MD V. TomicV. Tomic Department of Anesthesiology and Intensive Care Medicine, Friedrich-Schiller-University, Jena, Germany , S. RußwurmS. Rußwurm Department of Anesthesiology and Intensive Care Medicine, Friedrich-Schiller-University, Jena, Germany , R.A. ClausR.A. Claus Department of Anesthesiology and Intensive Care Medicine, Friedrich-Schiller-University, Jena, Germany , F.M. BrunkhorstF.M. Brunkhorst Department of Anesthesiology and Intensive Care Medicine, Friedrich-Schiller-University, Jena, Germany , K. BodeK. Bode Department of Anesthesiology and Intensive Care Medicine, Friedrich-Schiller-University, Jena, Germany , F. BloosF. Bloos Department of Anesthesiology and Intensive Care Medicine, Friedrich-Schiller-University, Jena, Germany , K. ReinhartK. Reinhart Department of Anesthesiology and Intensive Care Medicine, Friedrich-Schiller-University, Jena, Germany and M. BauerM. Bauer Department of Anesthesiology and Intensive Care Medicine, Friedrich-Schiller-University, Jena, Germany E. MöllerE. Möller SIRS-Lab GmbH, Jena, Germany , M. BlaessM. Blaess SIRS-Lab GmbH, Jena, Germany and H.-P. DeignerH.-P. Deigner SIRS-Lab GmbH, Jena, Germany M. BruegelM. Bruegel Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital Leipzig, Leipzig, Germany and J. ThieryJ. Thiery Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital Leipzig, Leipzig, Germany J. WippermannJ. Wippermann Department of Cardiothoracic and Vascular Surgery, Friedrich-Schiller-University, Jena, Germany and T. WahlersT. Wahlers Department of Cardiothoracic and Vascular Surgery, Friedrich-Schiller-University, Jena, Germany Originally published16 May 2006https://doi.org/10.1161/CIRCULATIONAHA.105.615328Circulation. 2006;113:e766We thank Dr O'Dwyer and colleagues for their letter in which they raise concerns regarding interpretation of the discordance between protein and cytokine mRNA levels in patients undergoing coronary bypass surgery and regarding the isolation of RNA from whole blood by the PaxGene methodology.1 We would like to use this opportunity to clarify that RNA was isolated for all experiments by the PaxGene whole blood method, including the positive control, ie, ex vivo endotoxin-spiked whole blood cultures. We agree that the legend to Figure 3 in our original article is somewhat misleading because we refer to "total RNA isolated from [peripheral blood mononuclear cells]," although as is increasingly acknowledged, RNA might also be derived from sources other than peripheral blood mononuclear cells exclusively.2,3Preparation of RNA for microarrays is indeed a critical preanalytical step, as differences attributable to the mode of RNA isolation might even outweigh changes in transcript expression caused by a biological insult, as shown by the Glue Grant consortium.4 Nevertheless, although there are changes that clearly depend on the method of RNA preparation, the question remains which of the established methods may best reflect the cell response in vivo and yield the de facto transcription pattern. Although PaxGene offers a number of technical advantages, increased noise and reduced responsiveness reflect possible limitations. However, immediate-early gene response during and after isolation are likely to result in false-positive results for all protocols that involve cell enrichment. Furthermore, induction of genes on density gradient centrifugation or magnetic sorting, for example, might depend on the functional state of leukocytes, and thus would be different for naïve as opposed to primed leukocytes. Therefore, RNA isolation for reliable transcriptional profiling will likely be plagued by the lack of an accepted methodology for the near future. On the basis of our recent results in stabilized whole blood, it will be a challenge to investigate gene expression in subclasses of leukocytes and in platelets from patients undergoing coronary bypass surgery.DisclosuresNone.1 Tomic V, Rußwurm S, Moller E, Claus RA, Blaess M, Brunkhorst F, Bruegel M, Bode K, Bloos F, Wippermann J, Wahlers T, Deigner HP, Thiery J, Reinhart K, Bauer M. Transcriptomic and proteomic patterns of systemic inflammation in on-pump and off-pump coronary artery bypass grafting. Circulation. 2005; 112: 2912–2920.LinkGoogle Scholar2 Jozsef L, Khreiss T, El Kebir D, Filep JG. Activation of TLR-9 induces IL-8 secretion through peroxynitrite signaling in human neutrophils. J Immunol. 2006; 176: 1195–1202.CrossrefMedlineGoogle Scholar3 Gnatenko DV, Dunn JJ, McCorkle SR, Weissmann D, Perrotta PL, Bahou WF. Transcript profiling of human platelets using microarray and serial analysis of gene expression. Blood. 2003; 101: 2285–2293.CrossrefMedlineGoogle Scholar4 Feezor RJ, Baker HV, Mindrinos M, Hayden D, Tannahill CL, Brownstein BH, Fay A, MacMillan S, Laramie J, Xiao W, Moldawer LL, Cobb JP, Laudanski K, Miller-Graziano CL, Maier RV, Schoenfeld D, Davis RW, Tompkins RG; Inflammation and Host Response to Injury, Large-Scale Collaborative Research Program. Whole blood and leukocyte RNA isolation for gene expression analyses. Physiol Genomics. 2004; 19: 247–254.CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetails May 16, 2006Vol 113, Issue 19 Advertisement Article InformationMetrics https://doi.org/10.1161/CIRCULATIONAHA.105.615328 Originally publishedMay 16, 2006 PDF download Advertisement

Background-Coronary artery bypass grafting (CABG) using cardiopulmonary bypass (CPB) provides controlled operative conditions but induces a whole-body inflammatory response capable of initiating devastating morbidity and mortality. Although technically more demanding, deliberate avoidance of CPB in off-pump surgery attenuates the physiological insult associated with CABG.Methods and Results-To systematically assess the molecular mechanisms underlying the better-preserved remote organ function, we studied gene expression patterns in leukocytes and plasma proteomic response to on-pump and off-pump CABG. Proteomic analysis confirmed ( tumor necrosis factor-alpha, interleukin [IL]-6, IL-10) and expanded (eg, interferon [ IFN]-gamma, granulocyte colony - stimulating factor [G-CSF], monocyte chemotactic protein-1, macrophage inflammatory protein-1 beta)the mediators released on CPB, whereas blood leukocyte transcriptomics suggested that circulating leukocytes are not primarily responsible for this response. Interestingly, release of some cytokines (eg, IL-6, IFN-gamma, G-CSF) was observed on off-pump surgery to a similar extent but with delayed kinetics. A total of 45 of 4868 transcripts were identified to be significantly altered as a result of initiation of CPB. Systematic analysis of transcriptional activation by CPB revealed primarily genes involved in inflammation-related cell - cell communication ( such as L-selectin or intercellular adhesion molecule-2)and signaling ( such as IL-1, IL-8, or IL-18 receptors and toll-like receptors 4, 5, and 6), thus confirming a "primed" phenotype of circulating peripheral blood mononuclear cells.Conclusions-Gene array and multiplex protein analysis, only in concert, can illuminate the molecular mechanisms responsible for systemic sequelae of CPB and indicate that circulating leukocytes overexpress adhesion and signaling factors after contact with CPB, which potentially facilitates their trapping, eg, in the lungs and may promote a subsequent tissue-associated inflammatory response.