Treatment Of Human Sepsis Research Articles

Kallistatin treatment attenuates lethality and organ injury in mouse models of established sepsis.

IntroductionKallistatin levels in the circulation are reduced in patients with sepsis and liver disease. Transgenic mice expressing kallistatin are resistant to lipopolysaccharide (LPS)-induced mortality. Here, we investigated the effect of kallistatin on survival and organ damage in mouse models of established sepsis.MethodsMice were rendered septic by cecal ligation and puncture (CLP), or endotoxemic by LPS injection. Recombinant human kallistatin was administered intravenously six hours after CLP, or intraperitoneally four hours after LPS challenge. The effect of kallistatin treatment on organ damage was examined one day after sepsis initiation, and mouse survival was monitored for four to six days.ResultsHuman kallistatin was detected in mouse serum of kallistatin-treated mice. Kallistatin significantly reduced CLP-induced renal injury as well as blood urea nitrogen, serum creatinine, interleukin-6 (IL-6), and high mobility group box-1 (HMGB1) levels. In the lung, kallistatin decreased malondialdehyde levels and HMGB1 and toll-like receptor-4 (TLR4) synthesis, but increased suppressor of cytokine signaling-3 (SOCS3) expression. Moreover, kallistatin attenuated liver injury, serum alanine transaminase (ALT) levels and hepatic tumor necrosis factor-α (TNF-α) synthesis. Furthermore, delayed kallistatin administration improved survival in CLP mice by 38%, and LPS-treated mice by 42%. In LPS-induced endotoxemic mice, kallistatin attenuated kidney damage in association with reduced serum creatinine, IL-6 and HMGB1 levels, and increased renal SOCS3 expression. Kallistatin also decreased liver injury in conjunction with diminished serum ALT levels and hepatic TNF-α and TLR4 expression. In cultured macrophages, kallistatin through its active site increased SOCS3 expression, but this effect was blocked by inhibitors of tyrosine kinase, protein kinase C and extracellular signal-regulated kinase (ERK), indicating that kallistatin stimulates a tyrosine-kinase-protein kinase C-ERK signaling pathway.ConclusionsThis is the first study to demonstrate that delayed human kallistatin administration is effective in attenuating multi-organ injury, inflammation and mortality in mouse models of polymicrobial infection and endotoxemia. Thus, kallistatin therapy may provide a promising approach for the treatment of sepsis in humans.

A Historical Perspective on Sepsis

In North America, approximately 700,000 cases of sepsis occur each year, with mortality ranging between 30% and 50%. The American Journal of Pathology has featured numerous articles on the topic, revealing mechanistic insights gleaned from both experimental rodent models and human sepsis. Nonetheless, there remains urgent need to determine the basis for sepsis-related complications and how they can be avoided, as well as how they can be most effectively treated once recognized. This historical perspective reviews what we currently understand about the mechanisms of sepsis, as well as the barriers that remain in our treatment strategies.

Forsythoside B Protects Against Experimental Sepsis by Modulating Inflammatory Factors

The present study investigated the effects of Forsythoside B on an experimental model of sepsis induced by caecal ligation and puncture (CLP) in rats and elucidated the potential mechanism in cultured RAW 264.7 cells. Results showed that Forsythoside B concentration-dependently down-regulated the levels of TNF-α, IL-6 and high-mobility group-box 1 protein (HMGB1) in lipopolysaccharide (LPS)-stimulated RAW264.7 cells, inhibited the IκB kinase (IKK) pathway and modulated nuclear factor (NF)- κB. Intravenous injection (i.v.) of Forsythoside B alone or plus Imipenem reduced serum levels of TNF-α, IL-6, HMGB1, triggering receptor expressed on myeloid cells (TREM-1) and endotoxin, while the serum level of IL-10 was up-regulated and myeloperoxidase (MPO) in lung, liver and small intestine was reduced. Meanwhile, i.v. of Forsythoside B alone or plus Imipenem reduced CLP-induced lethality in rats. These data indicated that the antisepsis effect of Forsythoside B is mediated by decreasing local and systemic levels of a wide spectrum of inflammatory mediators. Its antisepsis mechanism may be that Forsythoside B binds to LPS and reduces the biological activity of serum LPS, and inhibits NF-κB activition. Our studies enhance the case for the use of Forsythoside B in sepsis. Forsythoside B itself has promise as a therapy for the treatment of sepsis in humans.

Expression and function of triggering receptor expressed on myeloid cells-1 (TREM-1) on canine neutrophils

The dog is both a valued veterinary species and a widely used translational model for sepsis research. However, relatively little work has been performed evaluating potential biomarkers present during canine infection. Triggering receptor expressed on myeloid cells-1 (TREM-1) has shown promise as a biomarker for infection and pneumonia in humans. Here we describe, for the first time, the expression and function of the canine orthologue of TREM-1. Expression of TREM-1 on canine neutrophils is significantly up-regulated by stimulation with microbial agonists of TLR2/6, TLR1/2, and TLR4/MD2. Kinetics of TREM-1 protein up-regulation are rapid, with significant increases observed within 2 hr of neutrophil activation. Functionally, canine TREM-1 synergistically enhances LPS-induced production of IL-8, TNF-α and a canine orthologue of CXCL1. Collectively, these data suggest that TREM-1 expression in dogs, as it is in humans, is an amplifier of pro-inflammatory responses to microbial products. These results have direct application to veterinary diagnostics as well as the potential to enhance the utility of canine disease models in the assessment of potential therapeutics in the treatment of human sepsis.

Comparative study between intravenous immunoglobulins and standard treatment in septic patients

The use of intravenous immunoglobulins (IVIG) in the treatment of human sepsis remains controversial. The aim of this study was to assess the effects of IVIG in patients with severe sepsis with or without septic shock on mortality and morbidity compared with standard treatment of sepsis.

Ethyl Pyruvate: A Novel Treatment for Sepsis

Pyruvic acid is a three-carbon alpha-ketocarboxylic acid that plays a central role in intermediary metabolism, being the final product of glycolysis and the starting substrate for the tricarboxylic acid cycle. Ethyl pyruvate, which is a simple aliphatic ester derived from pyruvic acid, has been shown to improve survival and ameliorate organ system dysfunction in mice with peritonitis induced by cecal ligation and perforation, even when treatment is started as late as 12-24 hours after the onset of sepsis. In studies using lipopolysaccharide-stimulated RAW 264.7 murine macrophage-like cells, ethyl pyruvate inhibits activation of the pro-inflammatory transcription factor, NF-kappaB, and down-regulates secretion of a number of pro-inflammatory cytokines, such as TNF. In this reductionist in vitro system, ethyl pyruvate also blocks secretion of the late-appearing pro-inflammatory cytokine-like molecule, high mobility group B1 (HMGB1). In murine models of endotoxemia or sepsis, treatment with ethyl pyruvate decreases circulating levels of TNF and HMGB1. While the molecular events responsible for the salutary effects of ethyl pyruvate remain to be elucidated, one mechanism may involve covalent modification of a critical thiol residue in the p65 component of NF-kappaB. Ethyl pyruvate warrants evaluation as a therapeutic agent for the treatment of sepsis in humans.

A Cardiovascular Drug Rescues Mice from Lethal Sepsis by Selectively Attenuating a Late-Acting Proinflammatory Mediator, High Mobility Group Box 1

The pathogenesis of sepsis is mediated in part by bacterial endotoxin, which stimulates macrophages/monocytes to sequentially release early (e.g., TNF, IL-1, and IFN-gamma) and late (e.g., high mobility group box 1 (HMGB1) protein) proinflammatory cytokines. The recent discovery of HMGB1 as a late mediator of lethal sepsis has prompted investigation for development of new experimental therapeutics. We found that many steroidal drugs (such as dexamethasone and cortisone) and nonsteroidal anti-inflammatory drugs (such as aspirin, ibuprofen, and indomethacin) failed to influence endotoxin-induced HMGB1 release even at superpharmacological concentrations (up to 10-25 microM). However, several steroid-like pigments (tanshinone I, tanshinone IIA, and cryptotanshinone) of a popular Chinese herb, Danshen (Salvia miltiorrhiza), dose dependently attenuated endotoxin-induced HMGB1 release in macrophage/monocyte cultures. A water-soluble tanshinone IIA sodium sulfonate derivative (TSNIIA-SS), which has been widely used as a Chinese medicine for patients with cardiovascular disorders, selectively abrogated endotoxin-induced HMGB1 cytoplasmic translocation and release in a glucocorticoid receptor-independent manner. Administration of TSNIIA-SS significantly protected mice against lethal endotoxemia and rescued mice from lethal sepsis even when the first dose was given 24 h after the onset of sepsis. The therapeutic effects were partly attributable to attenuation of systemic accumulation of HMGB1 (but not TNF and NO) and improvement of cardiovascular physiologic parameters (e.g., decrease in total peripheral vascular resistance and increase in cardiac stroke volume) in septic animals. Taken together, these data re-enforce the pathogenic role of HMGB1 in lethal sepsis, and support a therapeutic potential for TSNIIA-SS in the treatment of human sepsis.

A high-throughput quantitative multiplex kinase assay for monitoring information flow in signaling networks: application to sepsis-apoptosis.

To treat complex human diseases effectively, a systems-level approach is needed to understand the interplay of environmental cues, intracellular signals, and cellular behaviors that underlie disease states. This approach requires high-throughput, multiplex techniques that measure quantitative temporal variations of multiple protein activities in the intracellular signaling network. Here, we describe a single microtiter-based format that simultaneously quantifies protein kinase activities in the phosphatidylinositol 3-kinase pathway (Akt), nuclear factor-kappaB pathway (IKK), and three core mitogen-activated protein kinase pathways (ERK, JNK1, MK2). These parallel high-throughput assays are stringently linear, redundantly specific, reproducible, and sensitive compared with classical low-throughput techniques. When applied to a model of sepsis-induced colon epithelial apoptosis, this approach identified a late phase of Akt activity as a critical mediator of cell survival that quantitatively contributed to the efficacy of insulin as an anti-apoptotic cue. Thus, sampling parallel nodes in the intracellular signaling network identified part of the molecular mechanism underlying the efficacy of insulin in the treatment of human sepsis.

Non-lethal Sepsis and Nitric Oxide Inhibition in the Guinea Pig

Nitric oxide (NO) is synthesized from arginine by three distinct isoforms of nitric oxide synthase (NOS). Two of these isoforms, endothelial NOS (eNOS, type III NOS) and neuronal NOS (nNOS, type I NOS) are expressed in a constitutive manner and are responsible for regulating physiological functions. The induction of the third isoform of nitric oxide synthase (iNOS) by inflammatory processes and the subsequent overproduction of NO is thought to contribute to the tissue damage that occurs in a number of diseases having an inflammatory component, such as sepsis. As a model of sepsis, non-lethal endotoxemia in Hartley guinea pigs was induced using three serotypes of lipopolysaccharide (LPS, 30 mg/kg, i.p.). Each stimulated an increase in total plasma nitrites 6 h following their administration. Treatment orally with two inhibitors of NOS, L-nitroarginine methyl ester (L-NAME), a non-selective inhibitor and N-iminoethyl-L-lysine (L-NIL), a selective iNOS inhibitor, 30 min after the induction of sepsis, inhibited (p < 0.05) the increase in plasma nitrites with ED50 values of 7 ± 1 and 0.4 ± 0.03 mg/kg, respectively, suggesting that NOS inhibitors may be useful in the treatment of human sepsis, or other diseases where excess NO levels have been implicated, such as asthma, arthritis and inflammatory bowel disease.

A synthetic lipid A analog, B464, provides significant protection against the cardiopulmonary derangements in porcine Gram-negative sepsis

Many of the cardiopulmonary derangements associated with Gram-negative sepsis result from the activation of monocytes and macrophages by endotoxin with the resultant release of humoral mediators such as TNFα. Lipid A has been shown to retain the majority of endotoxin toxicity, however lipid A from nontoxic organisms has been shown, in vitro, to antagonize the action of other toxic endotoxin species. We examined the effects of a synthetic analog of lipid A (B464), on the evolution of hemodynamic derangements and acute lung injury following experimental Gram-negative sepsis. Anesthetized, ventilated swine were made septic with a 1 h intravenous infusion of live Pseudomonas aeruginosa and studied for 5 h. A treatment group received a bolus of B464 (100 μg/kg) prior to sepsis and a 1 h infusion (100 μg/kg/h) during the P. aeruginosa induction. A control group received simply 0.9% saline. All animals were studied for 5 h. B464 treatment failed to alter septic pulmonary hypertension or the decline in cardiac output. Late recovery from systemic hypotension was associated with reversal of arterial acidosis. Septic neutropenia was unaltered and was associated with increased lung neutrophil (PMN) sequestration measured by lung myeloperoxidase activity. However, decreased bronchoalveolar lavage protein content and improved arterial oxygen tension indicated attenuated acute lung injury in B464 treated animals. These preliminary data indicate that B464 may prove to be an effective tool in the treatment of human sepsis.

Patterns of cytokines, plasma endotoxin, plasminogen activator inhibitor, and acute-phase proteins during the treatment of severe sepsis in humans.

To study the patterns of plasma concentrations of endotoxin, tumor necrosis factor-alpha (TNF), interleukin-6 (IL-6), plasminogen activator inhibitor-1, C-reactive protein, and serum amyloid A during the treatment of human sepsis. A prospective case series study. ICU of the Department of Internal Medicine, University Hospital Groningen, The Netherlands. Twenty consecutive patients (11 female, 9 male, mean age 67 yrs) with clinically defined sepsis. Eighteen patients were admitted from the outpatient emergency ward; two patients were already inpatients. The control group (n = 7) comprised patients with nonseptic shock. Ten (50%) septic patients had detectable endotoxemia (greater than 5 (ng/L). TNF concentrations on admission were increased in 94% of the septic patients, whereas IL-6 and plasminogen activator inhibitor plasma concentrations were increased in all septic patients. The septic group showed significantly (p less than .05) higher concentrations of TNF, IL-6, plasminogen activator inhibitor-1, C-reactive protein, and serum amyloid A compared with the nonseptic patients. In the septic group, we found a correlation of both IL-6 and plasminogen activator inhibitor concentrations with severity of illness (r2 = .33, p less than .05; r2 = .22, p less than .05, respectively). After the start of antibiotic treatment, high concentrations of TNF and plasminogen activator inhibitor persisted in the nonsurvivors in contrast to decreasing concentrations in most of the survivors. After an initial increase in seven patients, IL-6 concentrations decreased in all septic patients and also in nonsurvivors. This study confirms previous findings that: a) TNF is a major mediator involved in the pathogenesis of septic shock; b) plasminogen activator inhibitor activity is significantly increased in septic patients and might be involved in the pathogenesis of disseminated intravascular coagulation associated with sepsis; and c) IL-6 is involved in the pathophysiology of septic shock, although further studies are needed to determine whether IL-6 is directly involved in mediating the lethal complications of septic shock or whether it should be considered an "alarm hormone" that reflects endothelial cell injury. Our findings also suggest that the concentrations and trends of these mediators during treatment are valuable for monitoring septic patients.

Complement activation and the production of inflammatory mediators during the treatment of severe sepsis in humans.

Sepsis or septic shock is frequently associated with activation of the complement system, coagulation and fibrinolytic changes and the release of several cytokines. In this study we analyzed the relation of complement activation to the inflammatory mediators, hemodynamic and biochemical parameters and severity of illness and outcome in 20 consecutive patients with clinically defined sepsis. Levels of C3a and C3d were elevated in 90% of the patients (median levels 0.19 mg/l and 8.6 mg/l respectively) in comparison to 14% and 42%, respectively of 7 patients with non-septic shock. Levels of C4 were decreased in only 1 of the 20 septic patients. Levels of TNF and IL-6 were elevated in 94% and 100% of the patients, Levels of TNF and IL-6 were elevated in 94% and 100% of the patients, respectively (median levels 122 ng/l and 1300 U/ml) and were clearly interrelated (r = 0.67, p less than 0.01). C3a levels correlated with the APACHE II score (r = 0.57, p less than 0.05) and high C3a levels were associated with fatal outcome (p less than 0.05). C3a was also correlated inversely with mean arterial pressure (r = 0.50, p less than 0.01). Levels of complement C3a and C3d significantly correlated with levels of plasminogen activator inhibitor-1 (PAI) and correlated inversely with AT-III levels. We found no correlation between these complement products and leukocyte counts or lactate levels, nor was there a correlation between C3a or C3d and the cytokines TNF and IL-6. Levels of C3a and C3d did not decrease significantly during the first 24 h of treatment, in contrast to a clear decrease in IL-6 levels in all patients and a decrease in TNF in the surviving patients. TNF levels remained stable or increased in the non-survivors. We conclude that both the complement system and the cytokine system are involved in the pathogenesis of septic shock and may be involved in the development of some of the fatal complications like hypotension and disseminated intravascular coagulation.