加藤 由布

We aimed to investigate the effects of blood purification and cold saline injection sites on the transpulmonary thermodilution values. We measured the cardiac output of eight pigs in every combination of cold saline injection (left jugular and femoral veins) and blood purification sites (right jugular and femoral veins), with or without blood purification. We examined the influence of the difference between the presence and absence of blood purification, vascular sites for blood purification, and sites for cold saline injection on the transpulmonary thermodilution values. Cardiac output measured during blood purification using transpulmonary thermodilution was underestimated however, there was no difference between vascular sites. Cardiac output measured via injection of cold saline into the femoral vein was higher than that obtained through injection of cold saline into the jugular vein, with or without blood purification.

The aim of this study was to investigate the effects of recombinant human-soluble thrombomodulin (rTM) on lipopolysaccharide (LPS)-induced, platelet-dependent neutrophil extracellular trap (NET) formation (NETosis). Human peripheral blood neutrophils and platelets were co-incubated with or without LPS (0.2 μg/ml) in the presence and absence of rTM (2 μg/ml). NETosis was confirmed by immunostaining and confocal microscopy. In the absence of platelets, LPS did not induce NETosis in the neutrophils. NETosis, however, was induced by LPS when neutrophils were co-cultured with platelets (64 % of neutrophils). Notably, rTM was able to fully inhibit NETosis in neutrophils cultured with platelets and in the presence of LPS. rTM did not induce NETosis in this co-culture system (p &lt 0.01 versus LPS in the absence of rTM). These results show that rTM can suppress LPS-induced platelet-dependent NETosis in vitro.

Promising results have been reported with blood purification as adjuvant treatment; however, the immunological mechanisms remain unclear. We have been developing a new blood purification system for regulating excessive immune reactions in severe sepsis and septic shock using a granulocyte adsorbing column (Adacolumn [Ada]), and a cytokine-adsorbing hemofilter (AN69ST hemofilter [AN69]). Fresh porcine blood was circulated for 6 h in five experimental groups including Ada and AN69 to assess the effects of leukocyte adsorption, phagocytic activity and adhesiveness of granulocytes. In the present study, we found that Ada mainly adsorbed granulocytes and monocytes, but not lymphocytes. The phagocytic activity level of granulocytes decreased, and adhesiveness increased, but the number of CD11b-positive cells markedly decreased in the current system. Elevated cytokine levels (IL-1 beta, IL-8 and IL-10) at the outlet of Ada were significantly lower than at the outlet of AN69 due to cytokine adsorption. Further studies are needed to better understand cellular interactions.

The high mobility group box 1 protein (HMGB1) is an alarmin that plays an important role in sepsis and has been recognized as a promising target with a wide therapeutic window ; however, no drugs or devices are currently in practical use. Here we demonstrate the removal capacity of HMGB1 using seven internationally available membranes in vitro. High cut-off (HCO) membrane showed lower clearance than the adsorbing-membranes such as PMMA and AN69ST. AN69ST showed the dramatically high adsorption clearance of 60 mL/min in dealing with 100 mL/min of test solution flow. Similar results were obtained in the case of plasma. Moreover, no saturation of HMGB1 on AN69ST was observed. For the treatment of septic shock, we have selected the high-volume, high flow modality using 2.1 m^2 PMMA dialyser, with sustained high-efficiency daily diafiltration using a mediator-adsorbing membrane (SHEDD-fA), for breaking the vicious cycle of mediators. In our study, subjects were enrolled as septic shock patients and most patients were in septic shock without renal failure. We demonstrated the effectiveness for septic shock and amazingly high clearance of HMGB1, IL-6. IL-8 and IL-10. Adsorption is a promising mechanism to remove large-molecular-weight cytokines such as HMGB1 effectively.