Insanity is doing the same thing over and over again and expecting different results.
—Albert Einstein (1879–1955)
Severe sepsis and septic shock is responsible for significant morbidity, mortality, and health care resource consumption worldwide. Although mortality has decreased over the last decade largely through early diagnosis (1), interventions, and supportive care, it continues to be unacceptable. Sepsis is the most expensive diagnosis necessitating hospitalization, with hospital costs exceeding $60 billion per year in the United States (2).
Sepsis is initiated by an infectious agent stimulating the expression of a wide and complex array of proinflammatory, anti-inflammatory, and apoptotic biomarkers (3). Elevated circulatory concentrations of these biomarkers have been implicated in the pathogenesis of organ dysfunction and mortality. Logically, these observations have given rise to numerous trials based on the hypothesis that antagonizing these biomarkers will improve outcomes. Although showing great promise in animal models, these therapies have been either equivalent or inferior to placebo in humans. After many decades and billions of dollars invested in animal models and clinical immunotherapy therapeutic trials (4); a product does not exist for clinical use. In the last year alone, three large multicenter randomized control trials have resulted in no outcome benefit. These trials include human recombinant activated protein C (5), eritoran tetrasodium (E5564, a Toll-like receptor 4 [TLR-4] antagonist) (6), and talactoferrin α (recombinant human lactoferrin) (7).
Improving the time to diagnosis and intervention has been shown to have a significant impact on outcomes in acute myocardial infarction, stroke, and trauma. This was made possible through a better understanding of the early pathogenesis of these diseases, leading to more specific targeting for adjunctive therapies. Over the last decade, a similar paradigm shift in clinical management has occurred for sepsis and has robustly led to significant mortality reduction (8). Although the causes for previously failed immunotherapy trials are numerous; a prolonged and inconsistent time from disease onset to therapeutic intervention is a common feature.
To maximize the use of targeted adjunctive immunotherapy, a comprehensive examination of early circulatory biomarker activity is needed to realize the optimal outcome benefit. The purpose of this article was to present new patient-level data on the early natural history of circulatory biomarker activity in the most proximal phases of severe sepsis and septic shock presentation. These findings will then be superimposed upon previous human outcome trials identified in the current literature targeting these specific biomarkers. It is quite possible that the timing of enrollment and intervention may be a significant underlying cause for repeated failures of these immunotherapy trials.
MATERIALS AND METHODS
Description of patient cohort
Plasma samples were obtained from a serum repository including patients enrolled in the study examining early goal-directed therapy (EGDT) in severe sepsis and septic shock (8, 9). To understand the natural pattern of biomarker activity and limit the influence of hemodynamic optimization on inflammation, only control patients (not receiving EGDT) were examined (9). Patients were excluded if they were on immunosuppressive therapy or replacement corticosteroid therapy or had care limitations provided on admission. No patients received recombinant activated protein C.
Timing of data collection
Demographics, baseline characteristics, and organ dysfunction scores were obtained at enrollment. Plasma samples and laboratory data were collected at 0, 3, 6, 12, 24, 48, 60, and 72 h after patient enrollment. Patients were followed up until hospital discharge and at 28 and 60 days.
The following biomarkers were assayed (Table 1): interleukin 1β (IL-1β), IL-1ra, IL-6, IL-8, IL-10, intercellular adhesion molecule (ICAM), tumor necrosis factor-α (TNF-α), caspase 3, D-dimer, high-mobility group protein 1 (HMGB1), vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP), and myeloperoxidase (MPO). Assay results were sent to the Henry Ford Hospital Department of Public Health Sciences, which maintained the database and performed the statistical analyses independent of the study investigators. The demographics, baseline clinical data, organ dysfunction scores, and mortality were examined by descriptive statistics.
We reviewed the literature for randomized immunotherapy trials to examine the timing of targeted immunomodulatory interventions in each study. We searched PubMed, MEDLINE, and Google Scholar for adult trials published in the last 25 years. Search terms used alone and in combination were “sepsis,” “severe sepsis,” “septic shock,” “biomarker activity,” “animal model of sepsis,” “human model of sepsis,” “immunotherapy trials,” “randomized trial,” “interleukins,” “timing of biomarker activity,” “immune-modulation,” “recombinant human activated protein C (rh-APC or drotrecogin alfa activated),” “IL-1ra,” “TNF-α,” “IL-6,” “IL-1β,” “IL-8,” “D-dimer,” “HMGB1,” “MMP-9,” “VEGF,” “ICAM-1,” “MPO,” “caspase 3,” and “IL-10.” We focused on these previously mentioned biomarkers during our search because of the available data from our own patient cohort. In addition, some of the biomarkers have been prominent targets in clinical trials examining immunotherapy. A secondary search focused on animal models of sepsis and sepsis simulations to determine the timing of targeted biomarker in the randomized immunotherapy sepsis trials. The findings of these two searches were then superimposed upon published and unpublished early biomarker activity of human severe sepsis and septic shock patients (8, 9). We excluded review articles, pediatric studies, studies enrolling healthy volunteers, studies without specified time frame of enrollment, and studies examining statin or dietary supplements. We identified a total of 39 studies for our analysis (Fig. 1).
Complete biomarker data were available in 104 patients from the control group in the EDGT study. The mean age was 63.0 ± 17.1 years, and there was an enrollment time of 1.7 ± 2.2 h after hospital arrival (Table 2). Organ dysfunction scores, including Acute Physiology and Chronic Health Evaluation II score, Simplified Acute Physiology Score II, Multiple Organ Dysfunction Score, Sequential Organ Failure Assessment, were commensurate with previous sepsis immunotherapy outcome trials. The majority of patients met criteria for septic shock at enrollment, with overall in-hospital mortality of 39.2%.
The peak and nadir of the biomarkers examined over the 72-h study period are illustrated in Table 3, relative to the time frames of immunotherapeutic interventions identified in our literature review. Interleukin 6, IL-1β, and IL-10 were highest at presentation. At 3 h after patient enrollment, we observed a peak in IL-1ra, TNF-α, and VEGF levels. Matrix metalloproteinase 9 peaked at 6 h, and IL-8 at 12 h. Within 24 to 48 h, peak levels of D-dimer, HMGB1, ICAM-1, MPO, and caspase 3 were reached. Several markers had a bimodal pattern in their peak levels, with all markers decreasing noticeably to their nadir within 48 h of patient enrollment.
The history of biomarker activity
The immunological pathogenesis of sepsis was eloquently characterized by Bone (3) in two phases—an early proinflammatory phase shifts into a later anti-inflammatory phase. An ideal response occurs when these two phases are balanced. The proinflammatory phase lasts the initial 24 to 72 h following the insult. The anti-inflammatory phase begins after 72 h and can last 2 to 8 weeks or even longer. When there is an exaggerated early response, early mortality associated with shock may be the result. With an excessive later response, immune suppression may occur with later-onset infections and multiorgan failure. In some patients, this late anti-inflammatory response can predominate and lead to “immune-paralysis,” requiring immunomodulation therapy to restore necessary immune integrity. Based on this observed early biomarker activity in animal models and our presented data; the phases of inflammation described by Bone are not distinct and essentially overlap. This observation questions the appropriateness of single treatment target for immunomodulation in sepsis. Furthermore, the greatest biomarker variability is measured in hours, not days, and can be bimodal following the initial presentation. The bimodal peaks of some biomarkers indicate that additional stimuli or interactions may contribute to the natural history of circulatory biomarker concentrations. For example, high levels of TNF-α, IL-6, IL-1ra, and IL-8 are associated with early hemodynamic deterioration and mortality in intensive care unit (ICU)–based studies (9, 10). This hemodynamic deterioration leading to tissue hypoxia can itself be a stimulus for inflammation in the progression septic shock (9, 11). This “second hit,” which is multifactorial, has been previously described in the development of multiorgan failure and, particularly, the delayed need for mechanical ventilation (12) and renal replacement therapy (13). Outcome differences have been observed for early-versus late-onset septic shock (10).
The animal and human models of biomarker activity
In animal models, the sepsis insult is distinct (i.e., cecal perforation), and the elevation of biomarkers is seen within hours. In well-controlled human studies simulating sepsis, the response to an insult (endotoxin) begins with symptoms of the systemic inflammatory response syndrome within 1 h, with biomarker elevation within 3 h after endotoxin introduction (14, 15). Changes in organ function are seen within 3 to 6 h, with many peaking by 3 to 5 h (14, 16). The consistently reproducible insults of these human and animal experimental sepsis models, lack of comorbidities, well-controlled standards of care, and the timing of insult to immunotherapy intervention create a high level of homogeneity. Although this concept is debatable (17), this level of homogeneity is difficult to reproduce in human outcome trials (17). A step toward understanding why successful human and animal models in sepsis have yet to yield success begins with addressing and understanding the variables contributing to this heterogeneity (Table 4).
The clinical reality of sepsis management and its outcome implications
Based on a review of temporal biomarker activity in animal and human models of sepsis and our own observations in patients presenting with community-acquired sepsis; the most effective time to intervention with immunotherapy is immediate or within the first 12 h of onset of severe sepsis and septic shock. This timing is either to directly antagonize or to prevent the peak levels of biomarkers that occur within this period.
However, the reality is that there are significant delays in both diagnosis and therapeutic interventions, with outcome and pathogenic implications when patients are enrolled in clinical trials. The emergency department (ED) is the portal of entry for more than 52.4%, general practice unit (GPU) for 34.8%, and the ICU for 12.8% of all sepsis patients presenting to the hospital (18). The mortality rates are 27.6%, 41.3%, and 46.8% for each of these respective locations. Thus, it is critically important that patients are diagnosed as soon as possible because mortality can almost be 20% higher if a patient is admitted to the GPU instead of the ICU from the ED. Patients with a sepsis diagnosis can frequently have symptoms for up to 24 h before hospital arrival. When this is combined with an ED waiting time from 5 to 24 h, there is significant “incubation” time before definitive care and study enrollment (19).
After hospital presentation, the disease severity can be underestimated, and these patients are not uncommonly admitted to the GPU to later decompensate requiring ICU transfer (20). Carr et al. (21) showed that up to 10% of in-hospital cardiac arrests carry an admission diagnosis of pneumonia. This median time to the cardiac arrest associated with septic shock was 18.9 h after ICU and 24.8 h after GPU admission. Thus, observational studies reveal that 87.2% of severe sepsis and septic shock patients originate outside the ICU (18). This source of heterogeneity in illness severity and location (community- vs. hospital-acquired sepsis) upon enrollment may provide insight into the failure of previous human trials of immunotherapy.
The influence of hemodynamic status and optimization on biomarker activity
The degree of resuscitation impacts biomarker activity before enrollment. The temporal patterns of IL-1ra, ICAM-1, TNF-α, caspase 3, and IL-8 from admission to the first 72 h of hospitalization are significantly associated with the severity of global tissue hypoxia, organ dysfunction, and mortality. These findings identify global tissue hypoxia as an important contributor to the early inflammatory response and support the role of hemodynamic optimization in supplementing other established therapies during this diagnostic and therapeutic window of opportunity (9, 10).
Sevransky et al. (22) noted in a review that clinical trials inconsistently specify hemodynamic goals. The wide range of hemodynamic treatment targets suggests a lack of agreement for management of patients with sepsis. The integral components to hemodynamic optimization such as fluid, vasoactive therapy, transfusion, mechanical ventilation, and sedation may all impact biomarker activity. This lack of consistency in hemodynamic goals may contribute to heterogeneity in treatment effects for clinical trials of novel sepsis therapies (22).
The influence of antibiotic therapy on inflammation
Antibiotic-induced endotoxin release has been observed in both animal and human models of sepsis after antibiotic administration (23). The antibiotic ceftazidime exerts an antioxidant effect in vitro. It inhibits perferryl-mediated lipoperoxidation iron scavenging, neutralizes hydrogen peroxide chloride, and quenches singlet oxygen (24). Multiple animal studies have shown a reduction in levels of IL-1 and TNF-α and mortality, when administering tetracycline (a proposed inhibitor of MMP-9) 20 min before i.v. lipopolysaccharide (LPS) with repeat half dose at 6 and 24 h, compared with controls (25). These effects were no longer statistically significant when tetracycline administration was delayed as little as 1 h following LPS (40%–60% survival), and at 4 h after LPS, tetracycline offered no benefit over controls (10%–20% survival). Similar findings have been shown up to 12 h in the cecal perforation model (26). Experimental studies of gram-negative sepsis have shown considerable attenuation of the systemic inflammatory response following i.v. administration of macrolides such as clarithromycin (27). Thus, the influence of antibiotic administration refers not only to its outcome implications (28) but also to its contribution to the heterogeneity in early biomarker levels (18).
Generalized immune modulation
Toll-like receptors bind to pathogen-associated molecular patterns and initiate intracellular signaling cascades that result in the synthesis and release of proinflammatory biomarkers such as TNF-α, IL-1, IL-6, and IL-8. Toll-like receptor 4, in particular, binds LPS and other ligands, forming a TLR-4–CD14 complex, which plays a prominent role in the inflammatory reaction to infection (29). TAK-242, a TLR-4–mediated signaling inhibitor, interferes with signal transduction mediated through the CD14–TLR-4 complex without directly inhibiting the binding of LPS to TLR-4 and has been shown to provide a survival advantage in vitro (29). Despite promising phase II trials, the most recent phase III trial of eritoran tetrasodium treatment blocking TLR-4 has failed to reduce mortality (6, 30). The mean time from shock or respiratory failure was approximately 19 h with initiation of the study drug within 36 h of onset of shock or respiratory failure (31).
Glucocorticoids have a range of anti-inflammatory actions leading to general suppression of inflammation. Glucocorticoids can inhibit the intracellular upregulation of necrosis factor κB, which stimulates the production of key proinflammatory biomarkers TNF-α and IL-1. They also inhibit production of the inducible nitric oxide synthase and decrease the release of other biomarkers including platelet activating factor (32). High-dose corticosteroids in sepsis have not consistently resulted in outcome benefit (33). The two most recent multicenter trials examining low-dose corticosteroids in septic shock show conflicting results in regard to outcome (34, 35). The time of intervention, 8 h in the first trial (positive benefit) versus up to 72 h in the second trial (no benefit), may hold an explanation for these divergent findings.
Outcome studies examining ibuprofen (36) administered up to 24 h after organ failure and cyclooxygenase inhibitor (lornoxicam), which allowed for enrollment up to 8 h following ICU admission, have shown no differences in mortality between treatment and control arm (37). Despite a recent trial showing no outcome benefit (5), it is plausible that the beneficial effects may be realized if drotrecogin alfa activated is administered at an even earlier period.
Talactoferrin, an iron-binding protein found not only in mucosal secretions but also in secondary granules of neutrophils, has been shown to have anti-infective and anti-inflammatory properties. Among various immunomodulatory properties of recombinant human lactoferrin is the ability to compete with E-selectin for LPS binding. This binding has been shown to downregulate to production of reactive oxygen species in neutrophils and has been associated with the prevention of further tissue damage following infection if administered early. The phase 2 trial of oral talactoferrin in patients with severe sepsis and septic shock achieved an absolute 28-day all-cause mortality reduction of 12.5% (placebo group mortality 26.9%, talactoferrin group 14.4%, P = 0.05) and in patients without cardiovascular dysfunction (23.3% placebo vs. 2.6% talactoferrin group) (30). The most recent phase II/III trial of oral talactoferrin in sepsis (OASIS trial) was discontinued because of no observed mortality benefit (38). Randomization had to occur within 24 h of severe sepsis or septic shock onset with an additional 4 h to initiation of treatment representing a significant lead time based on the dynamic nature of early biomarker activity.
Other approaches of generalized immunomodulation have yet to show that they are feasible for the general sepsis population. Smaller trials of hemofiltration show promising results in a well-defined surgical population (39). Trials with granulocyte-macrophage colony-stimulating factor have been shown to be safe and effective in restoring the monocytic immunocompetence (40). The treatment, however, was not able to demonstrate significant mortality reductions.
LIMITATIONS AND FUTURE DIRECTIONS
Biomarkers may have significant effects at the receptor or tissue level, which suggest that detectable circulatory levels may not accurately reflect disease activity within the cell. The development of diagnostic tools that allow real-time and accurate determination of biomarker concentrations may significantly contribute to improved characterization of the individual inflammatory state of the patient. Some of the larger failed trials did not publish their data, and others did not detail the time to treatment from patient presentation. These limitations hinder investigators who seek methodological information to avoid continued failure in the design of future sepsis clinical trials.
At the most proximal point of hospital presentation, patients presenting with community-acquired severe sepsis and septic shock already have elevated circulatory biomarker levels. These circulatory biomarkers overlap, have bimodal patterns, and generally peak between 3 and 36 h while diminishing over the subsequent 72 h of observation. When this early natural history and the clinical realities of sepsis care are taken into account, prior sepsis immunotherapy trial enrollment is generally delayed after the window of peak circulatory biomarker concentrations. Thus, there is a need to recalibrate the timing of enrollment and intervention in future immunotherapy trials that still may hold great promise for this deadly disease.
The authors thank the EGDT Collaborative Group for this study composed of the following: Quanniece Rivers, BS; Katie Floyd, MA; Shajuana Rivers; Stacie Young; Ruben Flores, PhD; Scott Rongey, PhD; Scok-Won Lee, PhD; H. Matilda Horst, MD, Kandis K. Rivers, MD; Khalil K. Rivers, Arturo Suarez, MD, Damon Goldsmith, Peter Nwoke, MD, Bernhard Knoblich, MD; the nursing, technical, administrative, and support staff in the ED and ICUs. They also thank the patients and their families; the Department of Emergency Medicine nurses, residents, senior staff attending physicians, pharmacists, patient advocates, technicians, billing and administration personnel, and medical and surgical ICU nurses and technicians; and the Departments of Respiratory Therapy, Pathology, Medical Records, and Admitting and Discharge for their patience and cooperation in making this study possible.
ALI — acute lung injury
ARDS — acute respiratory distress syndrome
CD14 — cluster of differentiation 14
ED — emergency department
EGDT — early goal-directed therapy
GPU — general practice unit
HMGB1 — high-mobility group protein 1
ICAM-1 — intercellular adhesion molecule 1
ICU — intensive care unit
IL-1ra — interleukin 1 receptor antagonist
IL-1β — interleukin 1beta
IL-6 — interleukin 6
IL-8 — interleukin 8
IL-10 — interleukin 10
LPS — lipopolysaccharide
MMP — matrix metalloproteinase
MPO — myeloperoxidase
NO — nitric oxide
TLR-4 — Toll-like receptor 4
TNF-α — tumor necrosis factor alpha
VEGF — vascular endothelial growth factor
1. Kumar G, Kumar N, Taneja A, Kaleekal T, Tarima S, McGinley E, Jimenez E, Mohan A, Khan RA, Whittle J, et al.: Nationwide trends of severe sepsis in the 21st century (2000–2007). Chest
140: 1223–31, 2011.
2. Andrews R, Elixhauser A. The national hospital bill: growth trends and 2005 update on the most expensive conditions by payer. Healthcare Cost and Utilization Project. 2007. Available at: http://www.hcup-us.ahrq.gov/reports/statbriefs/sb42.pdf
:1–13. Last accessed May 2012.
3. Bone RC: Immunologic dissonance: a continuing evolution in our understanding of the systemic inflammatory response syndrome (SIRS) and the multiple organ dysfunction syndrome (MODS) [see comments]. Ann Intern Med
125: 680–687, 1996.
4. Nasraway SA: The problems and challenges of immunotherapy in sepsis. Chest
123: 451S–459S, 2003.
5. Ranieri VM, Thompson BT, Barie PS, Dhainaut JF, Douglas IS, Finfer S, Gardlund B, Marshall JC, Rhodes A, Artigas A, et al.: Drotrecogin alfa (activated) in adults with septic shock. N Engl J Med
366: 2055–2064, 2012.
8. Rivers E, Nguyen B, Havstad S, Ressler J, Muzzin A, Knoblich B, Peterson E, Tomlanovich M: Early goal-directed therapy in the treatment of severe sepsis and septic shock. N Engl J Med
345: 1368–1377, 2001.
9. Rivers EP, Kruse JA, Jacobsen G, Shah K, Loomba M, Otero R, Childs EW: The influence of early hemodynamic optimization on biomarker patterns of severe sepsis and septic shock. Crit Care Med
35: 2016–2024, 2007.
10. Roman-Marchant O, Orellana-Jimenez CE, De Backer D, Melot C, Vincent JL: Septic shock of early or late onset: does it matter? Chest
126: 173–178, 2004.
11. Brun-Buisson C, Doyon F, Carlet J, Dellamonica P, Gouin F, Lepoutre A, Mercier JC, Offenstadt G, Regnier B: Incidence, risk factors, and outcome of severe sepsis and septic shock in adults. A multicenter prospective study in intensive care units. French ICU Group for Severe Sepsis. JAMA
274: 968–974, 1995.
12. Estenssoro E, Gonzalez F, Laffaire E, Canales H, Saenz G, Reina R, Dubin A: Shock on admission day is the best predictor of prolonged mechanical ventilation in the ICU. Chest
127: 598–603, 2005.
13. Kiers HD, Griesdale DE, Litchfield A, Reynolds S, Gibney RT, Chittock D, Pickkers P, Sweet DD: Effect of early achievement of physiologic resuscitation goals in septic patients admitted from the ward on the kidneys. J Crit Care
25: G563–G569, 2010.
14. Dorresteijn MJ, van Eijk LT, Netea MG, Smits P, van der Hoeven JG, Pickkers P: Iso-osmolar prehydration shifts the cytokine response towards a more anti-inflammatory balance in human endotoxemia. J Endotoxin Res
11: 287–293, 2005.
15. Hollenberg SM: Mouse models of resuscitated shock. Shock
24 (Suppl 1): 58–63, 2005.
16. Martich GD, Boujoukos AJ, Suffredini AF: Response of man to endotoxin. Immunobiology
187: 403–416, 1993.
17. Dyson A, Singer M: Animal models of sepsis: why does preclinical efficacy fail to translate to the clinical setting? Crit Care Med
37: S30–S37, 2009.
18. Levy MM, Dellinger RP, Townsend SR, Linde-Zwirble WT, Marshall JC, Bion J, Schorr C, Artigas A, Ramsay G, Beale R, et al.: The Surviving Sepsis Campaign: results of an international guideline-based performance improvement program targeting severe sepsis. Crit Care Med
38: 367–374, 2010.
19. Chalfin DB, Trzeciak S, Likourezos A, Baumann BM, Dellinger RP: Impact of delayed transfer of critically ill patients from the emergency department to the intensive care unit. Crit Care Med
35: 1477–1483, 2007.
20. Lundberg JS, Perl TM, Wiblin T, Costigan MD, Dawson J, Nettleman MD, Wenzel RP: Septic shock: an analysis of outcomes for patients with onset on hospital wards versus intensive care units. Crit Care Med
26: 1020–1024, 1998.
21. Carr GE, Edelson DP, Yuen TC, McConville JF, Kress JP, VandenHoek TL, Hall JB: In-Hospital cardiac arrest among patients with coexisting pneumonia: a report from the American Heart Association’s get with the guidelines—resuscitation program. Am J Respir Crit Care Med
183: A6339, 2011.
22. Sevransky JE, Nour S, Susla GM, Needham DM, Hollenberg S, Pronovost P: Hemodynamic goals in randomized clinical trials in patients with sepsis: a systematic review of the literature. Crit Care
11: R67, 2007.
23. Holzheimer RG: Antibiotic induced endotoxin release and clinical sepsis: a review. J Chemother
13 (Spec. No. 1): 159–172, 2001.
24. Mathy-Hartert M, Deby-Dupont G, Deby C, Jadoul L, Vandenberghe A, Lamy M: Cytotoxicity towards human endothelial cells, induced by neutrophil myeloperoxidase: protection by ceftazidime. Mediators Inflamm
4: 437–443, 1995.
25. Milano S, Arcoleo F, D’Agostino P, Cillari E: Intraperitoneal injection of tetracyclines protects mice from lethal endotoxemia downregulating inducible nitric oxide synthase in various organs and cytokine and nitrate secretion in blood. Antimicrob Agents Chemother
41: 117–121, 1997.
26. Halter JM, Pavone LA, Steinberg JM, Gatto LA, DiRocco J, Landas S, Nieman GF: Chemically modified tetracycline (COL-3) improves survival if given 12 but not 24 hours after cecal ligation and puncture. Shock
26: 587–591, 2006.
27. Kanoh S, Rubin BK: Mechanisms of action and clinical application of macrolides as immunomodulatory medications. Clin Microbiol Rev
23: 590–615, 2010.
28. Kumar A, Roberts D, Wood KE, Light B, Parrillo JE, Sharma S, Suppes R, Feinstein D, Zanotti S, Taiberg L, et al.: Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock. Crit Care Med
34: 1589–1596, 2006.
29. Tsujimoto H, Ono S, Efron PA, Scumpia PO, Moldawer LL, Mochizuki H: Role of Toll-like receptors in the development of sepsis. Shock
29: 315–321, 2008.
30. Tidswell M, Tillis W, Larosa SP, Lynn M, Wittek AE, Kao R, Wheeler J, Gogate J, Opal SM: Phase 2 trial of eritoran tetrasodium (E5564), a Toll-like receptor 4 antagonist, in patients with severe sepsis. Crit Care Med
38: 72–83, 2010.
31. Rice TW, Wheeler AP, Bernard GR, Vincent JL, Angus DC, Aikawa N, Demeyer I, Sainati S, Amlot N, Cao C, et al.: A randomized, double-blind, placebo-controlled trial of TAK-242 for the treatment of severe sepsis. Crit Care Med
38: 1685–1694, 2010.
32. Vincent JL, Sun Q, Dubois MJ: Clinical trials of immunomodulatory therapies in severe sepsis and septic shock. Clin Infect Dis
34: 1084–1093, 2002.
33. Effect of high-dose glucocorticoid therapy on mortality in patients with clinical signs of systemic sepsis. The Veterans Administration Systemic Sepsis Cooperative Study Group. N Engl J Med
317: 659–665, 1987.
34. Annane D, Sebille V, Charpentier C, Bollaert PE, Francois B, Korach JM, Capellier G, Cohen Y, Azoulay E, Troche G, et al.: Effect of treatment with low doses of hydrocortisone and fludrocortisone on mortality in patients with septic shock. JAMA
288: 862–871, 2002.
35. Sprung CL, Annane D, Keh D, Moreno R, Singer M, Freivogel K, Weiss YG, Benbenishty J, Kalenka A, Forst H, et al.: Hydrocortisone therapy for patients with septic shock. N Engl J Med
358: 111–124, 2008.
36. Arons MM, Wheeler AP, Bernard GR, Christman BW, Russell JA, Schein R, Summer WR, Steinberg KP, Fulkerson W, Wright P, et al.: Effects of ibuprofen on the physiology and survival of hypothermic sepsis. Ibuprofen in Sepsis Study Group. Crit Care Med
27: 699–707, 1999.
37. Memis D, Karamanlioglu B, Turan A, Koyuncu O, Pamukcu Z: Effects of lornoxicam on the physiology of severe sepsis. Crit Care
8: R474–R482, 2004.
39. Shimizu T, Hanasawa K, Sato K, Umeki M, Koga N, Naganuma T, Sato S, Shimonishi T, Ikeda T, Matsuno N, et al.: Direct hemoperfusion with polymyxin-B–immobilized fiber columns improves septic hypotension and reduces inflammatory mediators in septic patients with colorectal perforation. Langenbecks Arch Surg
394: 303–311, 2009.
40. Meisel C, Schefold JC, Pschowski R, Baumann T, Hetzger K, Gregor J, Weber-Carstens S, Hasper D, Keh D, Zuckermann H, et al.: Granulocyte-macrophage colony-stimulating factor to reverse sepsis-associated immunosuppression: a double-blind, randomized, placebo-controlled multicenter trial. Am J Respir Crit Care Med
180: 640–648, 2009.
41. Dinarello CA: The role of interleukin-1 in host responses to infectious diseases. Infect Agents Dis
1: 227–236, 1992.
42. Boermeester MA, van Leeuwen PA, Coyle SM, Wolbink GJ, Hack CE, Lowry SF: Interleukin-1 blockade attenuates mediator release and dysregulation of the hemostatic mechanism during human sepsis. Arch Surg
130: 739–748, 1995.
43. Fisher CJ, Jr, Dhainaut JF, Opal SM, Pribble JP, Balk RA, Slotman GJ, Iberti TJ, Rackow EC, Shapiro MJ, Greenman RL, et al.: Recombinant human interleukin 1 receptor antagonist in the treatment of patients with sepsis syndrome. Results from a randomized, double-blind, placebo-controlled trial. Phase III rhIL-1ra Sepsis Syndrome Study Group. JAMA 271: 1836–1843, 1994.
44. Opal SM, Fisher CJ, Jr, Dhainaut JF, Vincent JL, Brase R, Lowry SF, Sadoff JC, Slotman GJ, Levy H, Balk RA, et al.: Confirmatory interleukin-1 receptor antagonist trial in severe sepsis: a phase III, randomized, double-blind, placebo-controlled, multicenter trial. The Interleukin-1 Receptor Antagonist Sepsis Investigator Group. Crit Care Med 25: 1115–1124, 1997.
45. Hein OV, Misterek K, Tessmann JP, van Dossow V, Krimphove M, Spies C: Time course of endothelial damage in septic shock: prediction of outcome. Crit Care
9: R323–R330, 2005.
46. Abraham E, Anzueto A, Gutierrez G, Tessler S, San Pedro G, Wunderink R, Dal Nogare A, Nasraway S, Berman S, Cooney R, et al.: Double-blind randomised controlled trial of monoclonal antibody to human tumour necrosis factor in treatment of septic shock. NORASEPT II Study Group. Lancet 351: 929–933, 1998.
47. Abraham E, Wunderink R, Silverman H, Perl TM, Nasraway S, Levy H, Bone R, Wenzel RP, Balk R, Allred R, et al.: Efficacy and safety of monoclonal antibody to human tumor necrosis factor alpha in patients with sepsis syndrome. A randomized, controlled, double-blind, multicenter clinical trial. TNF-alpha MAb Sepsis Study Group. JAMA
273: 934–941, 1995.
48. Cohen J, Carlet J: INTERSEPT: an international, multicenter, placebo-controlled trial of monoclonal antibody to human tumor necrosis factor-alpha in patients with sepsis. International Sepsis Trial Study Group. Crit Care Med 24: 1431–1440, 1996.
49. Fisher CJ Jr, Opal SM, Dhainaut JF, Stephens S, Zimmerman JL, Nightingale P, Harris SJ, Schein RM, Panacek EA, Vincent JL, et al.: Influence of an anti-tumor necrosis factor monoclonal antibody on cytokine levels in patients with sepsis. The CB0006 Sepsis Syndrome Study Group. Crit Care Med 21: 318–327, 1993.
50. Panacek EA, Marshall JC, Albertson TE, Johnson DH, Johnson S, MacArthur RD, Miller M, Barchuk WT, Fischkoff S, Kaul M, et al.: Efficacy and safety of the monoclonal anti-tumor necrosis factor antibody F(ab′)2 fragment afelimomab in patients with severe sepsis and elevated interleukin-6 levels. Crit Care Med
32: 2173–2182, 2004.
51. Reinhart K, Karzai W: Anti-tumor necrosis factor therapy in sepsis: update on clinical trials and lessons learned. Crit Care Med
29: S121–S125, 2001.
52. Rice TW, Wheeler AP, Morris PE, Paz HL, Russell JA, Edens TR, Bernard R: Safety and efficacy of affinity-purified, anti-tumor necrosis factor-alpha, ovine Fab for injection (CytoFab) in severe sepsis. Crit Care Med
34: 2271–2281, 2006.
53. Staubach KH, Schroder J, Stuber F, Gehrke K, Traumann E, Zabel P: Effect of pentoxifylline in severe sepsis: results of a randomized, double-blind, placebo-controlled study. Arch Surg
133: 94–100, 1998.
54. Kirschenbaum L, Astiz M, Rackow EC: Antibodies to TNF-alpha: too little, too late? Crit Care Med 26: 1625–1626, 1998.
55. Suffredini AF, Fantuzzi G, Badolato R, Oppenheim JJ, O’Grady NP: New insights into the biology of the acute phase response. J Clin Immunol
19: 203–214, 1999.
56. Mees ST, Toellner S, Marx K, Faendrich F, Kallen KJ, Schroeder J, Haier J, Kahlke V: Inhibition of interleukin-6–transsignaling via gp130-Fc in hemorrhagic shock and sepsis. J Surg Res
157: 235–242, 2009.
57. Dandona P, Nix D, Wilson MF, Aljada A, Love J, Assicot M, Bohuon C: Procalcitonin increase after endotoxin injection in normal subjects. J Clin Endocrinol Metab
79: 1605–1608, 1994.
58. Hein O, Misterek K, Tessmann J-P, van Dossow V, Krimphove M, Spies C: Time course of endothelial damage in septic shock: prediction of outcome. Critical Care 9: R323–R330, 2005.
59. Abraham E, Naum C, Bandi V, Gervich D, Lowry SF, Wunderink R, Schein RM, Macias W, Skerjanec S, Dmitrienko A, et al.: Efficacy and safety of LY315920Na/S-5920, a selective inhibitor of 14-kDa group IIA secretory phospholipase A2, in patients with suspected sepsis and organ failure. Crit Care Med
31: 718–728, 2003.
60. Zeiher BG, Steingrub J, Laterre PF, Dmitrienko A, Fukiishi Y, Abraham E: LY315920NA/S-5920, a selective inhibitor of group IIA secretory phospholipase A2, fails to improve clinical outcome for patients with severe sepsis. Crit Care Med
33: 1741–1748, 2005.
61. Jenkins JK, Carey PD, Byrne K, Sugerman HJ, Fowler AA 3rd: Sepsis-induced lung injury and the effects of ibuprofen pretreatment. Analysis of early alveolar events via repetitive bronchoalveolar lavage. Am Rev Respir Dis
143: 155–161, 1991.
62. Ikuta N, Taniguchi H, Kondoh Y, Takagi K, Hayakawa T: Sustained high levels of circulatory interleukin-8 are associated with a poor outcome in patients with adult respiratory distress syndrome. Intern Med
35: 855–860, 1996.
63. Sheu CC, Gong MN, Zhai R, Chen F, Bajwa EK, Clardy PF, Gallagher DC, Thompson BT, Christiani DC: Clinical characteristics and outcomes of sepsis-related vs non–sepsis-related ARDS. Chest 138: 559–567, 2010.
64. Folkesson HG, Matthay MA, Hebert CA, Broaddus VC: Acid aspiration-induced lung injury in rabbits is mediated by interleukin-8–dependent mechanisms. J Clin Invest
96: 107–116, 1995.
65. Walkey AJ, Summer R, Ho V, Alkana P: Acute respiratory distress syndrome: epidemiology and management approaches. Clin Epidemiol
4: 159–169, 2012.
66. Afshari A, Brok J, Moller AM, Wetterslev J: Inhaled nitric oxide for acute respiratory distress syndrome (ARDS) and acute lung injury in children and adults. Cochrane Database Syst Rev CD002787, 2010.
67. Cepkova M, Matthay MA: Pharmacotherapy of acute lung injury and the acute respiratory distress syndrome. J Intensive Care Med
21: 119–143, 2006.
68. Carney DE, McCann UG, Schiller HJ, Gatto LA, Steinberg J, Picone AL, Nieman GF: Metalloproteinase inhibition prevents acute respiratory distress syndrome. J Surg Res
99: 245–252, 2001.
69. Parsons PE, Eisner MD, Thompson BT, Matthay MA, Ancukiewicz M, Bernard GR, Wheeler AP: Lower tidal volume ventilation and plasma cytokine markers of inflammation in patients with acute lung injury. Crit Care Med 33: 1–6; discussion 230–232, 2005.
70. Paterson RL, Galley HF, Webster NR: The effect of N
-acetylcysteine on nuclear factor-kappa B activation, interleukin-6, interleukin-8, and intercellular adhesion molecule-1 expression in patients with sepsis. Crit Care Med
31: 2574–2578, 2003.
71. Poeze M, Froon AH, Ramsay G, Buurman WA, Greve JW: Decreased organ failure in patients with severe SIRS and septic shock treated with the platelet-activating factor antagonist TCV-309: a prospective, multicenter, double-blind, randomized phase II trial. TCV-309 Septic Shock Study Group. Shock
14: 421–428, 2000.
72. Bartlett RH: Extracorporeal life support in the management of severe respiratory failure. Clin Chest Med
21: 555–561, 2000.
73. Singer P, Shapiro H: Enteral omega-3 in acute respiratory distress syndrome. Curr Opin Clin Nutr Metab Care
12: 123–128, 2009.
74. Kacmarek RM, Wiedemann HP, Lavin PT, Wedel MK, Tutuncu AS, Slutsky AS: Partial liquid ventilation in adult patients with acute respiratory distress syndrome. Am J Respir Crit Care Med
173: 882–889, 2006.
75. Kesecioglu J, Beale R, Stewart TE, Findlay GP, Rouby JJ, Holzapfel L, Bruins P, Steenken EJ, Jeppesen OK, Lachmann B: Exogenous natural surfactant for treatment of acute lung injury and the acute respiratory distress syndrome. Am J Respir Crit Care Med
180: 989–994, 2009.
76. Shorr AF, Thomas SJ, Alkins SA, Fitzpatrick TM, Ling GS: D-Dimer correlates with proinflammatory cytokine levels and outcomes in critically ill patients. Chest
121: 1262–1268, 2002.
77. Riewald M, Petrovan RJ, Donner A, Mueller BM, Ruf W: Activation of endothelial cell protease activated receptor 1 by the protein C pathway. Science
296: 1880–1882, 2002.
78. Bernard GR, Vincent JL, Laterre PF, LaRosa SP, Dhainaut JF, Lopez-Rodriguez A, Steingrub JS, Garber GE, Helterbrand JD, Ely EW, et al.: Efficacy and safety of recombinant human activated protein C for severe sepsis. N Engl J Med
344: 699–709, 2001.
79. Warren BL, Eid A, Singer P, Pillay SS, Carl P, Novak I, Chalupa P, Atherstone A, Penzes I, Kubler A, et al.: Caring for the critically ill patient. High-dose antithrombin III in severe sepsis: a randomized controlled trial. JAMA
286: 1869–1878, 2001.
80. Mantell LL, Parrish WR, Ulloa L: HMGB-1 as a therapeutic target for infectious and inflammatory disorders. Shock
25: 4–11, 2006.
81. Yang H, Ochani M, Li J, Qiang X, Tanovic M, Harris HE, Susarla SM, Ulloa L, Wang H, DiRaimo R, et al.: Reversing established sepsis with antagonists of endogenous high-mobility group box 1. Proc Natl Acad Sci U S A
101: 296–301, 2004.
82. Tang Y, Lv B, Wang H, Xiao X, Zuo X: PACAP inhibit the release and cytokine activity of HMGB1 and improve the survival during lethal endotoxemia. Int Immunopharmacol
8: 1646–1651, 2008.
83. Sunden-Cullberg J, Norrby-Teglund A, Rouhiainen A, Rauvala H, Herman G, Tracey KJ, Lee ML, Andersson J, Tokics L, Treutiger CJ: Persistent elevation of high mobility group box-1 protein (HMGB1) in patients with severe sepsis and septic shock. Crit Care Med
33: 564–573, 2005.
84. Vanlaere I, Libert C: Matrix metalloproteinases as drug targets in infections caused by gram-negative bacteria and in septic shock. Clin Microbiol Rev 22: 224–239, Table of contents, 2009.
85. Albert J, Radomski A, Soop A, Sollevi A, Frostell C, Radomski MW: Differential release of matrix metalloproteinase-9 and nitric oxide following infusion of endotoxin to human volunteers. Acta Anaesthesiol Scand 47: 407–410, 2003.
86. Lalu MM, Csont T, Schulz R: Matrix metalloproteinase activities are altered in the heart and plasma during endotoxemia. Crit Care Med
32: 1332–1337, 2004.
87. Shapira L, Soskolne WA, Houri Y, Barak V, Halabi A, Stabholz A: Protection against endotoxic shock and lipopolysaccharide-induced local inflammation by tetracycline: correlation with inhibition of cytokine secretion. Infect Immun
64: 825–828, 1996.
88. Nakamura T, Ebihara I, Shimada N, Shoji H, Koide H: Modulation of plasma metalloproteinase-9 concentrations and peripheral blood monocyte mRNA levels in patients with septic shock: effect of fiber-immobilized polymyxin B treatment. Am J Med Sci 316: 355–360, 1998.
89. Cruz DN, Antonelli M, Fumagalli R, Foltran F, Brienza N, Donati A, Malcangi V, Petrini F, Volta G, Bobbio Pallavicini FM, et al.: Early use of polymyxin B hemoperfusion in abdominal septic shock: the EUPHAS randomized controlled trial. JAMA
301: 2445–2452, 2009.
90. Hao Q, Wang L, Tang H: Vascular endothelial growth factor induces protein kinase D–dependent production of proinflammatory cytokines in endothelial cells. Am J Physiol Cell Physiol 296: C821–C827, 2009.
91. Pickkers P, Sprong T, Eijk L, Hoeven H, Smits P, Deuren M: Vascular endothelial growth factor is increased during the first 48 hours of human septic shock and correlates with vascular permeability. Shock
24: 508–512, 2005.
92. Shapiro NI, Yano K, Okada H, Fischer C, Howell M, Spokes KC, Ngo L, Angus DC, Aird WC, et al.: A prospective, observational study of soluble FLT-1 and vascular endothelial growth factor in sepsis. Shock
29: 452–457, 2008.
93. van der Flier M, van Leeuwen HJ, van Kessel KP, Kimpen JL, Hoepelman AI, Geelen SP: Plasma vascular endothelial growth factor in severe sepsis. Shock
23: 35–38, 2005.
94. Yano K, Liaw PC, Mullington JM, Shih SC, Okada H, Bodyak N, Kang PM, Toltl L, Belikoff B, Buras J, et al.: Vascular endothelial growth factor is an important determinant of sepsis morbidity and mortality. J Exp Med
203: 1447–1458, 2006.
95. Karlsson S, Pettila V, Tenhunen J, Lund V, Hovilehto S, Ruokonen E: Vascular endothelial growth factor in severe sepsis and septic shock. Anesth Analg
106: 1820–1826, 2008.
96. Parent C, Eichacker PQ: Neutrophil and endothelial cell interactions in sepsis. The role of adhesion molecules. Infect Dis Clin North Am
13: 427–447, 1999.
97. van Griensven M, Probst C, Muller K, Hoevel P, Pape HC: Leukocyte-endothelial interactions via ICAM-1 are detrimental in polymicrobial sepsis. Shock
25: 254–259, 2006.
98. Kumasaka T, Quinlan WM, Doyle NA, Condon TP, Sligh J, Takei F, Beaudet A, Bennett CF, Doerschuk CM: Role of the intercellular adhesion molecule-1 (ICAM-1) in endotoxin-induced pneumonia evaluated using ICAM-1 antisense oligonucleotides, anti–ICAM-1 monoclonal antibodies, and ICAM-1 mutant mice. J Clin Invest 97: 2362–2369, 1996.
99. Welty-Wolf KE, Carraway MS, Huang YC, Simonson SG, Kantrow SP, Kishimoto TK, Piantadosi CA: Antibody to intercellular adhesion molecule 1 (CD54) decreases survival and not lung injury in baboons with sepsis. Am J Respir Crit Care Med
163: 665–673, 2001.
100. Endo S, Inada K, Kasai T, Takakuwa T, Yamada Y, Koike S, Wakabayashi G, Niimi M, Taniguchi S, Yoshida M: Levels of soluble adhesion molecules and cytokines in patients with septic multiple organ failure. J Inflamm
46: 212–219, 1995.
101. Kayal S, Jais JP, Aguini N, Chaudiere J, Labrousse J: Elevated circulating E-selectin, intercellular adhesion molecule 1, and von Willebrand factor in patients with severe infection. Am J Respir Crit Care Med
157: 776–784, 1998.
102. Sessler CN, Windsor AC, Schwartz M, Watson L, Fisher BJ, Sugerman HJ, Fowler AA 3rd: Circulating ICAM-1 is increased in septic shock. Am J Respir Crit Care Med
151: 1420–1427, 1995.
103. Friedman G, Jankowski S, Shahla M, Goldman M, Rose RM, Kahn RJ, et al.: Administration of an antibody to E-selectin in patients with septic shock. Crit Care Med
24: 229–233, 1996.
104. Eiserich JP, Baldus S, Brennan ML, Ma W, Zhang C, Tousson A, Castro L, Lusis AJ, Nauseef WM, White CR, et al.: Myeloperoxidase, a leukocyte-derived vascular NO oxidase. Science 296: 2391–2394, 2002.
105. Jepsen S, Herlevsen P, Knudsen P, Bud MI, Klausen NO: Antioxidant treatment with N
-acetylcysteine during adult respiratory distress syndrome: a prospective, randomized, placebo-controlled study. Crit Care Med
20: 918–923, 1992.
106. Angstwurm MW, Engelmann L, Zimmermann T, Lehmann C, Spes CH, Abel P, Strauss R, Meier-Hellmann A, Insel R, Radke J, et al.: Selenium in Intensive Care (SIC): results of a prospective randomized, placebo-controlled, multiple-center study in patients with severe systemic inflammatory response syndrome, sepsis, and septic shock. Crit Care Med
35: 118–126, 2007.
107. Wesche-Soldato DE, Swan RZ, Chung CS, Ayala A: The apoptotic pathway as a therapeutic target in sepsis. Curr Drug Targets 8: 493–500, 2007.
108. Sfeir T, Saha DC, Astiz M, Rackow EC: Role of interleukin-10 in monocyte hyporesponsiveness associated with septic shock. Crit Care Med
29: 129–133, 2001.
109. van der Poll T, Marchant A, Buurman WA, Berman L, Keogh CV, Lazarus DD, Nguyen L, Goldman M, Moldawer LL, Lowry SF: Endogenous IL-10 protects mice from death during septic peritonitis. J Immunol
155: 5397–5401, 1995.
110. Kumar A, Zanotti S, Bunnell G, Habet K, Anel R, Neumann A, Cheang M, Dinarello CA, Cutler D, Parrillo JE: Interleukin-10 blunts the human inflammatory response to lipopolysaccharide without affecting the cardiovascular response. Crit Care Med
33: 331–340, 2005.
111. Gogos CA, Drosou E, Bassaris HP, Skoutelis A: Pro- versus anti-inflammatory cytokine profile in patients with severe sepsis: a marker for prognosis and future therapeutic options. J Infect Dis
181: 176–180, 2000.