Kazuhiro Moriyama

In Vitro Evaluation of High Mobility Group Box 1 Protein Removal with Various Membranes for Continuous Hemofiltration

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 and devices are currently in practical use. We hypothesized that hemofilters composed of porous membranes or cytokine‐adsorbing membranes could remove HMGB1 from the blood. We performed experimental hemofiltration in vitro using four types of hemofilters composed of different membranes specifically designed for continuous hemofiltration. The test solution was a 1000‐mL substitution fluid containing 100 µg of HMGB1 and 35 g of bovine serum albumin. Experimental hemofiltration was conducted for 360 min in a closed loop circulation system. Among the four membranes, surface‐treated polyacrylonitrile (AN69ST) showed the highest capacity to adsorb HMGB1; it adsorbed nearly 100 µg of HMGB1 in the initial 60 min and showed a markedly high clearance rate (60.8 ± 5.0 mL/min) at 15 min. The polymethylmethacrylate membrane had half of the adsorption capacity of the AN69ST membrane. Although the highest sieving coefficient for HMGB1 was obtained with the high cut‐off polyarylethersulfone membrane, which correlated with a constant filtrate clearance rate, albumin loss was observed. However, no such removal of both HMGB1 and albumin was observed with the polysulfone membrane and tubing. We conclude that continuous hemofiltration using the AN69ST membrane is a promising approach for HMGB1‐related sepsis.

Sustained High-Efficiency Daily Diafiltration Using a Mediator-Adsorbing Membrane (SHEDD-fA) in the Treatment of Patients with Severe Sepsis

Sustained high-efficiency daily diafiltration using a mediator-adsorbing membrane (SHEDD-fA) is an effective, intensive modality for sepsis treatment. Here we describe the effectiveness of SHEDD-fA, which makes the best use of three principles: dialysis, filtration and adsorption, for mediator removal in the treatment of severe sepsis. SHEDD-fA was initiated after adequate fluid resuscitation and catecholamine support had been provided. A large (2.1 m(2)) polymethylmethacrylate membrane dialyzer was placed in the blood circuit. Operation conditions were as follows: blood flow rate 150 ml/min, filtration rate 1,500 ml/h (post-dilution), and dialysate flow rate 300-500 ml/min over 8-12 h daily. 55 consecutive patients with severe sepsis were studied. The following results were obtained: pressure catecholamine index significantly decreased at 3 h after initiation of septic shock, PaO(2)/F(IO2) significantly increased at 1 h after initiation of septic acute respiratory distress syndrome, a significant decrease in interleukin (IL)-6 level for 3 days was observed, and IL-6 was effectively adsorbed in one pass through the filter. The average sequential organ failure assessment score of patients was 10.1 and the mortality at 28 days was 16.4% (46 survived, 9 died). Because SHEDD-fA is an intensive and high-efficiency modality, removal of useful drugs or nutrients may be observed. Despite the fact that removal of useful substances cannot be ignored, we believe that an appropriate stage or timing can be identified so that we can avoid a vicious cycle and use blood purification with effective diffusion, filtration and adsorption. We demonstrate that SHEDD-fA may be an effective, intensive modality for the treatment of patients with severe sepsis and is a possible modality for cytokine modulation therapy.

Novel Blood Purification System for Regulating Excessive Immune Reactions in Severe Sepsis and Septic Shock: An Ex Vivo Pilot Study

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‐1β, 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.

Influence of Blood Purification and Differential Injection Sites of Cold Saline on Transpulmonary Thermodilution Values: Hemodynamics During Blood Purification

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.

In Vitro Study of Endotoxin Adsorption by a Polymyxin B-Immobilized Fiber Column

Background: Polymyxin B-immobilized fiber (PMX-F) columns are used as therapeutic interventions for septic shock. The clinical efficacy has been reported for 2-h applications, but their ability to adsorb endotoxin over longer treatments has not been fully elucidated. We hypothesized that PMX-F columns are capable of endotoxin removal for more than 2 h. Method: We designed closed circuits incorporating either a PMX-F column with an 8.5-mL priming volume (PMX-01R) or a sham-control column, and used inactivated fetal bovine serum as the circulating perfusate. Endotoxin was continuously injected at a fixed rate for 24 h, and perfusate endotoxin concentrations were measured at fixed time points. PMX-01R endotoxin adsorption was calculated from the difference in the endotoxin concentrations. Results: PMX-01R endotoxin adsorption increased continuously in a virtually linear manner. Conclusions: The PMX-01R column showed sustained endotoxin adsorption for at least 24 h. This indicated that PMX-F columns would be capable of clinical endotoxin removal for 24 h.