Caspase-3 activation, Bcl-2 contents, and soluble FAS-ligand are not related to the inflammatory marker profile in patients with sepsis and septic shock

The current comparative investigation analyses markers of inflammation and apoptosis in peripheral blood of intensive care unit (ICU) patients with postoperative/posttraumatic SIRS (systemic inflammatory response syndrome), sepsis, severe sepsis, or septic shock. Inflammatory markers (C-reactive protein [CRP], cytokines, metalloproteinases [MMPs]) and soluble FAS-Ligand (sCD178) were determined in plasma, and apoptosis-relevant antigens such as active caspase-3, Bcl-2, and sCD178 were quantified in whole-blood cell lysates. These parameters were analyzed daily in 20 postoperative/posttraumatic patients: 2 patients had SIRS, 5 suffered from sepsis (2 died), and 13 had septic shock (5 died). Active caspase-3, Bcl-2, and sCD178 were determined by ELISAand by fluorescence-activated cell sorting (FACS)-array kits using bead-assisted flow cytometry. Cytokines and MMPs were quantified by Luminex-assisted Beadlyte assays. Active caspase-3 was identified in defined samples of whole-blood lysates covering, for example, 5/7, 8/18, and 6/11 consecutive days during the patients' stay on the ICU. Also, sCD178 was detected on successive days. Peaks of active caspase-3 antigen contents in whole blood occurred independently of CRP and inflammatory cytokines such as tumor necrosis factor (TNF)-α and IL-6. In addition, high MMPs 1-3, 7-10, and 13 concentrations were detected. Interestingly, active caspase-3 and cell-associated sCD178 were either elevated simultaneously or in a close time window. The same was true for Bcl-2. In conclusion, activation of apoptosis can be determined in whole blood of postoperative/posttraumatic patients by active caspase-3 and by Bcl-2. Pro- and antiapoptotic effects during sepsis may occur independently of peaks in inflammatory markers. Apoptosis could explain modeling and remodeling of leukocyte subpopulations.