Even more importantly, the highest release of MCP-1 is associated to the lowest concentration of PCT. Also cell count was carried out at beginning and at the end

of each experiment and these values were not significantly different. Therefore a decrease of cell number should be excluded as a possible cause of reduced cytokine release, during the experiments which involved PCT. Despite the interest and novelty of the present findings, the LPS neutralization might be only one of the major modulatory mechanisms of PCT on “cytokine storm” during sepsis. As the present study is based on an in vitro model, some limitations regarding the drawing of more general conclusions, the extrapolation to the in vivo activity and the potential role of PCT in the therapy of systemic inflammatory diseases are acknowledged. LGX818 datasheet Conclusions In conclusion our data indicate a direct LPS neutralizing selleck chemicals llc effect of PCT, which suggests a significant PCT-induced inhibition on major mediators of the Th1, Treg and monocyte activation cascade stimulated by LPS. Any agent, including PCT, with the capability

to neutralize an early stimulus such as a bacterial product (e.g. LPS) and reduce the release of sepsis mediators deserves further investigation. These reported findings may provide new insights into biological and clinical events of the physiopathology of sepsis. Methods Chemicals The VS-4718 concentration LPS of E. coli strain O111:B4 was from Cambrex (Walkersville, USA); the LPS of S. typhimurium strain SL1102 was extracted and purified as previously described [17]. Recombinant next human procalcitonin was a generous gift of Randox (Randox Laboratories Ltd., Crumlin, UK). RPMI 1640 medium was obtained from Invitrogen (Carlsbad, CA). LAL test For

the evaluation of the LPS-neutralizing activity of PCT, LPS from S. typhimurium and E. coli were dissolved in sterile water for injection and then diluted in apyrogenic saline fluid (SF). Serial dilutions of PCT (5000, 500 and 50 pg/ml) in SF were incubated with 100 pg/ml of LPS from S. typhimurium and E. coli in a sterile conic tube at 37°C for 30 min. In preliminary experiments the reactivity of S. typhimurium and E. coli LPS was tested at different time points following LPS-PCT co-incubation. An incubation time of 30 min was found to be optimal based on higher LPS reactivity in the LAL test and more obvious PCT effect on such reactivity (Quirino A. personal observation). The LPS-neutralizing activity of PCT was analyzed using the chromogenic LAL-test (QCL-1000, Cambrex, Walkersville, USA) following manufacturer’s instructions, but the results were reported as optical density (O.D.) at 405 nm and were not corrected for the dilution factor [10]. PBMC stimulation For the study of the effects of PCT-pre-incubated LPS in cytokine release, human PBMC were obtained from blood samples of healthy donors, who gave informed consent.