Yoshihisa Tateishi

Gram-negative bacteremia induces greater magnitude of inflammatory response than Gram-positive bacteremia

IntroductionBacteremia is recognized as a critical condition that influences the outcome of sepsis. Although large-scale surveillance studies of bacterial species causing bacteremia have been published, the pathophysiological differences in bacteremias with different causative bacterial species remain unclear. The objective of the present study is to investigate the differences in pathophysiology and the clinical course of bacteremia caused by different bacterial species.MethodsWe reviewed the medical records of all consecutive patients admitted to the general intensive care unit (ICU) of a university teaching hospital during the eight-year period since introduction of a rapid assay for interleukin (IL)-6 blood level to routine ICU practice in May 2000. White blood cell count, C-reactive protein (CRP), IL-6 blood level, and clinical course were compared among different pathogenic bacterial species.ResultsThe 259 eligible patients, as well as 515 eligible culture-positive blood samples collected from them, were included in this study. CRP, IL-6 blood level, and mortality were significantly higher in the septic shock group (n = 57) than in the sepsis group (n = 127) (P < 0.001). The 515 eligible culture-positive blood samples harbored a total of 593 isolates of microorganisms (Gram-positive, 407; Gram-negative, 176; fungi, 10). The incidence of Gram-negative bacteremia was significantly higher in the septic shock group than in the sepsis group (P < 0.001) and in the severe sepsis group (n = 75, P < 0.01). CRP and IL-6 blood level were significantly higher in Gram-negative bacteremia (n = 176) than in Gram-positive bacteremia (n = 407) (P < 0.001, <0.0005, respectively).ConclusionsThe incidence of Gram-negative bacteremia was significantly higher in bacteremic ICU patients with septic shock than in those with sepsis or severe sepsis. Furthermore, CRP and IL-6 levels were significantly higher in Gram-negative bacteremia than in Gram-positive bacteremia. These findings suggest that differences in host responses and virulence mechanisms of different pathogenic microorganisms should be considered in treatment of bacteremic patients, and that new countermeasures beyond conventional antimicrobial medications are urgently needed.

Treatment of Severe Sepsis and Septic Shock by CHDF Using a PMMA Membrane Hemofilter as a Cytokine Modulator

It has been reported that various types of blood purification intended for the removal of humoral mediators, such as cytokines, were performed in patients with severe sepsis/septic shock. While high-volume hemofiltration, hemofiltration using high cut-off membrane filters, and direct hemoperfusion with a polymyxin-B immobilized column are widely used in the treatment of severe sepsis/septic shock, we perform continuous hemodiafiltration using a polymethylmethacrylate membrane hemofilter (PMMA-CHDF), which shows an excellent cytokine-adsorbing capacity, for the treatment of severe sepsis/septic shock. In our previous study, it was found that PMMA-CHDF could efficiently remove various pro-inflammatory cytokines such as TNFalpha, IL-6 and IL-8 from the bloodstream, resulting in early recovery from septic shock. Furthermore, PMMA-CHDF could remove anti-inflammatory cytokines such as IL-10 from bloodstream, suggesting that it might improve immunoparalysis as well. These findings suggest that PMMA-CHDF is useful for the treatment of patients with severe sepsis/septic shock as a cytokine modulator.

Differential pattern of cell-surface and soluble TREM-1 between sepsis and SIRS

OBJECTIVE Triggering receptor expressed on myeloid cells-1 (TREM-1) was reported to play a key roll in amplification of production of inflammatory cytokines. TREM-1 is suggested to be a specific biomarker for sepsis for this reason, but the clinical significance of TREM-1 has not been elucidated. We investigated TREM-1 expression on the cell-surface, and plasma levels of soluble TREM-1 (sTREM-1) in patients with non-infectious systemic inflammatory response syndrome (SIRS) and sepsis admitted to the ICU. METHODS Thirty-five patients with SIRS and 21 patients with sepsis admitted to ICU were subjected to the study. TREM-1 expressions on the surfaces of monocytes and neutrophils were measured by flow cytometry. Plasma sTREM-1 level and serum interleukin (IL)-6 level were measured. RESULTS Septic patients had decreased TREM-1 expression, clearly on neutrophils or to a lesser extent on monocyte compared to SIRS patients on ICU admission (neutrophils p<0.001, monocyte p<0.05). TREM-1 expression on neutrophils had a significant inverse correlation with serum IL-6 level (r=-0.64, p<0.0001). Plasma sTREM-1 level in septic patients was significantly higher than that in SIRS patients (p<0.05). Plasma sTREM-1 level positively correlated with severity score and non-survivors had increased plasma sTREM-1 level compared to survivors in all SIRS/sepsis patients (p<0.05). CONCLUSIONS Patients with sepsis had increased soluble TREM-1 and decreased TREM-1 expression on neutrophil compared to SIRS patients. sTREM-1 may be useful to evaluate disease severity and outcome of patients with SIRS or sepsis.

Non-Renal Indications for Continuous Renal Replacement Therapy: Current Status in Japan

Continuous renal replacement therapy (CRRT) has been extensively used in Japan as renal support for critically ill patients managed in the ICU. In Japan, active research has also been conducted on non-renal indications for CRRT, i.e. the use of CRRT for purposes other than renal support. Various methods of blood purification have been attempted to remove inflammatory mediators, such as cytokines, in patients with severe sepsis or septic shock. In these attempts, efficacy was demonstrated for continuous hemodiafiltration(CHDF) using a polymethyl methacrylate (PMMA) membrane hemofilter which is capable of adsorbing and removing various cytokines, plasma diafiltration, and online CHDF. Furthermore, a recently developed cytokine-adsorbing column is now under clinical evaluation. Definite evidence for the efficacy of CRRT for non-renal indications has not been established. In evaluating the efficacy of CRRT for non-renal indications, it is essential to focus on patients subjected to be studied, such as severe sepsis or septic shock, and to evaluate its indication, commencement, termination of therapy and also its therapeutic effects based on analysis of blood levels of the target substances to be removed (e.g. cytokines). IL-6 blood level appears to be useful as a variable for this evaluation. It is expected that evidence endorsing the validity of these methods now being attempted in Japan will be reported near future.

Autophagy-Related IRGM Polymorphism Is Associated with Mortality of Patients with Severe Sepsis

Objective Autophagy is the regulated catabolic process for recycling damaged or unnecessary organelles, which plays crucial roles in cell survival during nutrient deficiency, and innate immune defense against pathogenic microorganisms. Autophagy has been also reported to be involved in various conditions including inflammatory diseases. IRGM (human immunity-related GTPase) has an important function in eliminating Mycobacterium tuberculosis from host cells via autophagy. We examined the association between genetic polymorphism and clinical course/outcome in severely septic patients. Methods The study included 125 patients with severe sepsis/septic shock (SS) and 104 non-sepsis patients who were admitted to the intensive care unit (ICU) of Chiba University Hospital between October 2001 and September 2008 (discovery cohort) and 268 SS patients and 454 non-sepsis patients who were admitted to ICUs of five Japanese institutions including Chiba University Hospital between October 2008 and September 2012 (multi-center validation cohort). Three hundred forty seven healthy volunteers who consented to this study were also included. Genotyping was performed for a single-nucleotide polymorphism (SNP) within the coding region of IRGM, IRGM(+313) (rs10065172). Lipopolysaccharide challenge of whole blood from randomly selected healthy volunteers (n = 70) was performed for comparison of IRGM mRNA expression among different genotypes. Results No significant difference in genotypic distributions (CC/CT/TT) at the IRGM(+313) locus was observed among the three subject groups (SS, non-sepsis, and healthy volunteers) in either cohort. When mortality were compared, no significant difference was observed in the non-sepsis group, while TT homozygotes exhibited a significantly higher mortality than the CC+CT genotype category in the SS group for both cohorts (P = 0.043, 0.037). Lipopolysaccharide challenge to whole blood showed a significant suppression of IRGM mRNA expression in TT compared with the CC+CT genotype category (P = 0.019). Conclusions The data suggest that the IRGM(+313), an autophagy-related polymorphic locus, influences outcome in severely septic patients, with the possible involvement of autophagy in sepsis exacerbation.

Outcome prediction in sepsis combined use of genetic polymorphisms - A study in Japanese population.

Genetic polymorphisms have recently been found to be related to clinical outcome in septic patients. The present study investigated to evaluate the influence of genetic polymorphisms in Japanese septic patients on clinical outcome and whether use of genetic polymorphisms as predictors would enable more accurate prediction of outcome. Effects of 16 genetic polymorphisms related to pro-inflammatory mediators and conventional demographic/clinical parameters (age, sex, past medical history, and APACHE II score) on ICU mortality as well as disease severity during ICU stay were examined in the septic patients (n=123) admitted to the ICU between October 2001 and November 2007 by multivariable logistic regression analysis. ICU mortality was significantly associated with TNF -308GA, IL1β -31CT/TT, and APACHE II score. Receiver-operating characteristics (ROC) analysis demonstrated that, compared with APACHE II score alone (ROC-AUC=0.68), use of APACHE II score and two genetic parameters (TNF -308 and IL1β -31) enabled more accurate prediction of ICU mortality (ROC-AUC=0.80). Significant association of two genetic polymorphisms, TNF -308 and IL1β -31, with ICU mortality was observed in septic patients. In addition, combined use of these genetic parameters with APACHE II score may enable more accurate prediction of outcome in septic patients.

The role of hypercytokinemia in the pathophysiology of tumor lysis syndrome (TLS) and the treatment with continuous hemodiafiltration using a polymethylmethacrylate membrane hemofilter (PMMA-CHDF).

OBJECTIVE To examine the role of hypercytokinemia in the pathophysiology of tumor lysis syndrome (TLS) and the efficacy of continuous hemodiafiltration in the treatment of TLS. DESIGN AND SETTING Retrospective observational study in a general intensive care unit of a university hospital. PATIENTS Four patients with hematological disorder developing TLS after the treatment of anti-tumor chemotherapy. INTERVENTIONS Continuous hemodiafiltration using a polymethylmethacrylate membrane hemofilter (PMMA-CHDF) was performed at the onset of TLS. Blood samples were collected daily after ICU admission, and clinical parameters and blood levels of cytokines were evaluated. MEASUREMENTS AND RESULTS All four patients underwent induction anti-tumor chemotherapy, during which they developed hyperuricemia, hyperkalemia, and acute renal failure. Two of them also developed multiple organ failure. Serum levels of tumor necrosis factor (TNF) -alpha, interleukin-6 (IL-6), and IL-10 prior to the initiation of PMMA-CHDF were 102+/-85 pg/mL, 1097+/-546 pg/mL, and 98+/-83 pg/mL, respectively (mean +/- SD). After three days of PMMA-CHDF treatment, corresponding blood levels were 37+/-55 pg/mL, 326+/-511pg/mL, and 9+/-8 pg/mL, respectively. Thus, all cytokine levels were significantly decreased by three days of PMMA-CHDF treatment (p<0.05, paired t-test). Following three days of PMMA-CHDF treatment, blood urea nitrogen (BUN) and serum creatinine (Cre.) were significantly decreased (pre/post BUN 42.3+/-15.4/16.5+/-8.4 mg/dL, p<0.05, pre/post Cre. 2.7+/-1.2/1.2+/-0.6 mg/dL, mean +/- SD, p<0.05). Furthermore, the clinical condition of each patient was improved after the treatment of PMMA-CHDF, and all of four patients were survived. CONCLUSION Hypercytokinemia plays a pivotal role in the pathophysiology of TLS and PMMA-CHDF may be an effective therapeutic modality for TLS patients not only as renal replacement therapy but also as a cytokine modulator.

Comparison of interleukin-6 removal properties among hemofilters consisting of varying membrane materials and surface areas: an in vitro study.

Background/Aims: We sought to identify the most relevant hemofilter for cytokine removal based on the mechanisms of filtration and adsorption. Methods: Ascites were filtered using four types of hemofilters composed of different membrane materials (polymethyl methacrylate, PMMA, cellulose triacetate, CTA, or polysulfone, PS) and different surface areas (1.0 or 2.1 m2) to investigate the rate of interleukin-6 (IL-6) filtration. Next, ascites were perfused through each hemofilter without obtaining a filtrate to study each filter’s adsorptive capability. Results: The PMMA hemofilters resulted in a marginal observed IL-6 filtration rates, whereas the CTA and PS hemofilters resulted in highly effective IL-6 filtration. Regarding the IL-6 adsorptive capabilities of the filters, the PMMA hemofilter with a large surface area showed the highest level of IL-6 clearance. Conclusion: The present findings suggest that when cytokine removal based on filtration is desired, CTA or PS hemofilters should be selected. When IL-6 removal based on adsorption is desired, a PMMA hemofilter with a large surface area should be selected.

Blood purification in fulminant hepatic failure.

Fulminant hepatic failure (FHF) can be described as a potentially fatal condition presenting with hepatic encephalopathy (HE) and coagulopathy associated with acute hepatic dysfunction, regardless of its etiology. Blood purification (BP) is expected to be effective against HE and coagulopathy in FHF. In this paper, we outline the objectives and methods of BP in the treatments of cases with FHF and indicate a concrete method for and outcomes of BP at our facility. In high-flow dialysate continuous hemodiafiltration (HFCHDF), the conventional CHDF bedside console is connected to a personal dialysis console to induce a high flow rate of dialysate. With this method, the dialysate flow rate is about 500 ml/min at maximum, equivalent to about 50 times the dialysate flow rate during ordinary CHDF. The role of plasma exchange (PE) is considered a means of replacing useful substances, such as clotting factors in fresh frozen plasma rather than a means of removing pathogenic substances. As needed, slow PE (SPE) can be incorporated by connection in series. Analysis of data from 90 patients with FHF who underwent BP at our facility after 1990 revealed that restoration of consciousness was achieved in 33 (70.2%) of 47 cases when treated with HFCHDF. This survival in the HFCHDF group was significantly higher than that in the CHDF group. Analysis of data from cases in which ammonia could be measured continuously revealed that blood ammonia level decreased over time following HFCHDF. We also revealed that HFCHDF was useful for preventing the side effects of PE, such as hypernatremia, metabolic alkalosis, and sharp decrease in colloid osmotic pressure. It is concluded that HFCHDF is useful in the treatment of HE and for preventing the side effects of PE. Therefore, we suggested that HFCHDF + SPE should be standardized for the treatment of FHF.

Effects of a peripheral cholinesterase inhibitor on cytokine production and autonomic nervous activity in a rat model of sepsis

PURPOSE Recently, cholinergic anti-inflammatory pathway manipulation has been proposed as a new strategy to control cytokine production in sepsis. We investigated whether hypercytokinemia can be controlled via this pathway in an animal model of sepsis, with concomitant monitoring of autonomic nervous activity involving heart rate variability (HRV) analysis of electrocardiographic R-R intervals. METHODS Sixty-eight adult male Sprague-Dawley rats were used (28 for examination of cytokine production and autonomic nervous activity; 40 for survival analysis). Each part of the study involved four animal groups, including two control groups without drug administration. Sepsis was induced by cecal ligation and puncture (CLP). Distigmine bromide, a peripheral, non-selective cholinesterase inhibitor (0.01mg/kg), was administered subcutaneously 90 min after surgery. Continuous electrocardiograms were recorded for 5 min before and after surgery (at intervals of 5h) in CLP and sham-operated animals for HRV analysis. Blood samples were collected 20 h after surgery for serum cytokine and catecholamine assay. RESULTS On HRV analysis, distigmine inhibited reduction of total power and high-frequency components in CLP animals (P<0.05). Distigmine significantly inhibited cytokine induction (IL-6 and IL-10) (P<0.01) as well as increase in serum levels of noradrenaline and dopamine (P<0.05). Distigmine did not significantly improve CLP animal survival rate. CONCLUSIONS The cholinesterase inhibitor distigmine inhibited induction of inflammatory cytokines and catecholamines as well as HRV suppression in a rat CLP model, suggesting that an agent modulating the cholinergic anti-inflammatory pathway can control excess cytokine production involved in the pathogenesis of severe sepsis/septic shock.