Relationship between the inflammation and coagulation pathways in patients with severe sepsis: implications for therapy with activated protein C

Plasma thrombin activatable fibrinolysis inhibitor and tissue factor pathway inhibitor changes following sepsis

Sepsis-induced systemic inflammation results in coagulation abnormalities that may be different in gram-positive and gram-negative infections. We used ciprofloxacin to induce a predominantly gram-positive Enterococcus faecalis polymicrobial sepsis in rats. Ciprofloxacin-untreated rats exhibited a predominantly gram-negative polymicrobial sepsis. Rats were subjected to 30% body surface area burn (B), cecal ligation puncture (CLP) with a 22-gauge needle, and B + CLP. Ciprofloxacin-treated B + CLP rats showed a significant decrease in plasma thrombin activatable fibrinolysis inhibitor (TAFI) levels compared with sham rats. However, plasma tissue factor pathway inhibitor (TFPI) levels decreased significantly in B, CLP, and B + CLP groups compared with sham rats. The ciprofloxacin-untreated group showed a significant decrease in plasma TAFI levels in CLP and B + CLP and plasma TFPI levels decreased in all 3 groups compared with sham rats. Histological changes in the liver and kidney included vascular congestion and parenchyma bleed following B + CLP in ciprofloxacin-untreated rats. These results suggest that plasma TAFI and TFPI levels differ depending on the type of bacteria involved in the septic process.

Recombinant human activated protein C resets thrombin generation in patients with severe sepsis - a case control study

Introduction

Recombinant human activated protein C (rhAPC) is the first drug for which a reduction of mortality in severe sepsis has been demonstrated. However, the mechanism by which this reduction in mortality is achieved is still not clearly defined. The aim of the present study was to evaluate the dynamics of the anticoagulant, anti-inflammatory and pro-fibrinolytic action of rhAPC in patients with severe sepsis, by comparing rhAPC-treated patients with case controls.

Methods

In this prospectively designed multicenter case control study, 12 patients who were participating in the ENHANCE study, an open-label study of rhAPC in severe sepsis, were treated intravenously with rhAPC at a constant rate of 24 μg/kg/h for a total of 96 h. Twelve controls with severe sepsis matching the inclusion criteria received standard therapy. The treatment was started within 48 h after the onset of organ failure. Blood samples were taken before the start of the infusion and at 4, 8, 24, 48, 96 and 168 h, for determination of parameters of coagulation and inflammation.

Results

Sepsis-induced thrombin generation as measured by thrombin-antithrombin complexes and prothrombin fragment F1+2, was reset by rhAPC within the first 8 h of infusion. The administration of rhAPC did not influence parameters of fibrinolysis and inflammation. There was no difference in outcome or occurrence of serious adverse events between the treatment group and the control group.

Conclusion

Sepsis-induced thrombin generation in severely septic patients is reset by rhAPC within the first 8 h of infusion without influencing parameters of fibrinolysis and inflammation.

A new family of synthetic diterpenes that regulates cytokine synthesis by inhibiting IkappaBalpha phosphorylation

The synthesis and the biological evaluation of a new family diterpenes are presented. The synthetic studies were inspired by the structural framework of acanthoic acid (1) and yielded a family of compounds that were evaluated as anti-inflammatory agents. Among them, compounds 2, 10, 12, and 16 exhibited a very low nonspecific cytotoxicity and inhibited the synthesis of TNF-alpha with greater than 65 % efficacy at low micromolar concentrations. Cytokine-specificity studies revealed that these compounds also inhibited the synthesis of the proinflammatory cytokines IL-1beta and IL-6, while inhibition of IL-1ra and IL-8 synthesis was marginal and only occurred at high concentrations. Further studies, through EMSA and Western blot analyses, indicated that these compounds decreased the extent of phosphorylation of IkappaBalpha; this suggests that they exert their anti-inflammatory profile by inhibiting NF-kappaB-mediated cytokine synthesis. These findings imply that these diterpenes represent promising leads for the development of novel anti-inflammatory agents.

The puzzle of sepsis: fitting the pieces of the inflammatory response with treatment

Sepsis is a complex syndrome characterized by simultaneous activation of inflammation and coagulation in response to microbial insult. These events manifest as systemic inflammatory response syndrome (SIRS)/sepsis symptoms through release of proinflammatory cytokines, procoagulants, and adhesion molecules from immune cells and/or damaged endothelium.Conventional treatments have focused on source control, antimicrobials, vasopressors, and fluid resuscitation; however, a new treatment paradigm exists: that of treating the host response to infection with adjunct therapies including early goal directed therapy, drotrecogin alfa (activated), and immunonutrition. The multimechanistic drotrecogin alfa (activated) has been shown to reduce mortality in the severely septic patient when combined with traditional treatment. Therapies targeting improved oxygen and blood flow and reduction of apoptosis and free radicals are under investigation. Early sepsis diagnosis through detection of pro calcitonin, C reactive protein, sublingual CO2, and genetic factors may be beneficial. Ultimately, intervention timing may be the most important factor in reducing severe sepsis mortality.

Drotrecogin alfa (activated): a pharmacoeconomic review of its use in severe sepsis

Drotrecogin alfa (activated) [Xigris] (DAA), the recombinant form of human activated protein C, is approved as an adjunctive therapy for patients with severe sepsis (sepsis associated with > or = 1 organ system failure [OSF]). In the international, randomised, double-blind, placebo-controlled PROWESS (Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis) study, the absolute reduction in 28-day all-cause mortality with intravenous DAA 24 micro g/kg/h for 96 hours plus conventional care versus conventional care alone was 6.1%. Although lacking statistical power, a prospectively planned subgroup analysis of this study suggested that the absolute reduction in mortality increased in patients with a baseline APACHE (Acute Physiology and Chronic Health Evaluation) II score of > or = 25 or > or = 2 OSFs, with no clear treatment effect in patients with an APACHE II score of < or = 24 or 1 OSF. Three fully published cost-effectiveness/cost-utility models of DAA plus conventional care relative to conventional care alone adopted a national healthcare payer's and/or societal perspective in North America. The base-case (baseline) discounted incremental cost per life-year gained (LYG) with DAA for all patients with severe sepsis was $US15,801-33,300 (year of costing 2000-2002). The results were more favourable for patients with an APACHE II score of > or = 25 ($US10,833-19,723 per LYG), but considerably worse for patients with an APACHE II score of < or = 24 based on a post hoc reanalysis by the US FDA. Among several fully or partly published cost-effectiveness/cost-utility models that adopted a national healthcare payer's perspective in continental Western European countries, the base-case (baseline) undiscounted incremental cost per LYG was broadly similar and more favourable for patients with > or = 2 OSFs (9660-11,300 euros; year of costing/publication 1998/1999, 2000, 2002 or 2003) than for all patients with severe sepsis (13,436-15,071 euros) in those studies that reported both analyses. The DAA acquisition cost accounts for up to 95% of the additional cost of using the drug. In conclusion, DAA is a major advance in the treatment of severe sepsis, based on the significant mortality reduction observed in the PROWESS study. From a hospital/hospital pharmacy perspective, the drug is associated with a high acquisition cost and a small increase in other short-term costs. From a societal or national healthcare payer's perspective, however, its administration to patients who meet the PROWESS study inclusion criteria, especially individuals with more severe disease (e.g APACHE II score of > or =25 and/or > or = 2 OSFs), has a lifetime cost-effectiveness profile that compares well to that of many widely accepted therapies.