Precursor proadrenomedullin influences cardiomyocyte survival and local inflammation related to myocardial infarction.

Increased adrenomedullin (ADM) levels are associated with various cardiac diseases such as myocardial infarction (MI). ADM is cleaved off from the full-length precursor protein proadrenomedullin (ProADM) during its posttranslational processing. To date, no biological effect of ProADM is reported, while ADM infusion leads to antiapoptotic effects and improved cardiac function. Using an MI mouse model, we found an induction of ProADM gene as well as protein expression during the early phase of MI. This was accompanied by apoptosis and increasing inflammation, which substantially influence the post-MI remodeling processes. Simulating ischemia in vitro, we demonstrate that ProADM expression was increased in cardiomyocytes and cardiac fibroblasts. Subsequently, we treated ischemic cardiomyocytes with either ProADM or ADM and found that both proteins increased survival. This effect was diminishable by blocking the ADM1 receptor. To investigate whether ProADM and ADM play a role in the regulation of cardiac inflammation, we analyzed chemokine expression after treatment of cells with both proteins. While ProADM induced an expression of proinflammatory cytokines, thus promoting inflammation, ADM reduced chemokine expression. On leukocytes, both proteins repressed chemokine expression, revealing antiinflammatory effects. However, ProADM but not ADM dampened concurrent activation of leukocytes. Our data show that the full-length precursor ProADM is biologically active by reducing apoptosis to a similar extent as ADM. We further assume that ProADM induces local inflammation in affected cardiac tissue but attenuates exaggerated inflammation, whereas ADM has low impact. Our data suggest that both proteins are beneficial during MI by influencing apoptosis and inflammation.

Application of the SCAI classification in a cohort of patients with cardiogenic shock.

BACKGROUND: The Society of Cardiovascular Angiography and Interventions (SCAI) have recently proposed a new classification of cardiogenic shock (CS) dividing patients into five subgroups. OBJECTIVE: Aim of this study was to apply the SCAI classification to a cohort of patients presenting with CS and to evaluate its ability to predict 30-day survival. METHODS: SCAI CS subgroups were interpreted based on the recent consensus statement and then applied to N = 1,007 consecutive patients presenting with CS or large myocardial infarction (MI) between October 2009 and October 2017. The association between SCAI classification and 30-day all-cause mortality was assessed by logistic regression analysis. RESULTS: Mean age in the study cohort was 67 (±15) years, 72% were male. Mean lactate at baseline was 6.05 (±5.13) mmol/l and 51% of the patients had prior cardiac arrest. Overall survival probability was 50.6% (95% confidence interval [CI] 47.5-54.0%). In view of the SCAI classification, the survival probability was 96.4% (95% CI 93.7-99.0%) in class A, 66.1% (95% CI 50.2-87.1%) in class B, 46.1% (95% CI 40.6-52.4%) in class C, 33.1% (95% CI 26.6-41.1%) in class D, and 22.6% (95% CI 17.1-30.0%) in class E. Higher SCAI classification was significantly associated with lower 30-day survival (p < .01). CONCLUSION: In this large clinical cohort, the SCAI classification was significantly associated with 30-day survival. This finding supports the rationale of the SCAI CS classification and calls for a validation in a prospective trial.

A Novel Role for IL-6 Receptor Classic Signaling: Induction of RORγt+Foxp3+ Tregs with Enhanced Suppressive Capacity.

BACKGROUND: New therapies blocking the IL-6 receptor (IL-6R) have recently become available and are successfully being used to treat inflammatory diseases like arthritis. Whether IL-6 blockers may help patients with kidney inflammation currently remains unknown. METHODS: To learn more about the complex role of CD4+ T cell-intrinsic IL-6R signaling, we induced nephrotoxic nephritis, a mouse model for crescentic GN, in mice lacking T cell-specific IL-6Ra. We used adoptive transfer experiments and studies in reporter mice to analyze immune responses and Treg subpopulations. RESULTS: Lack of IL-6Ra signaling in mouse CD4+ T cells impaired the generation of proinflammatory Th17 cells, but surprisingly did not ameliorate the course of GN. In contrast, renal damage was significantly reduced by restricting IL-6Ra deficiency to T effector cells and excluding Tregs. Detailed studies of Tregs revealed unaltered IL-10 production despite IL-6Ra deficiency. However, in vivo and in vitro, IL-6Ra classic signaling induced RORγt+Foxp3+ double-positive Tregs (biTregs), which carry the trafficking receptor CCR6 and have potent immunoregulatory properties. Indeed, lack of IL-6Ra significantly reduced Treg in vitro suppressive capacity. Finally, adoptive transfer of T cells containing IL-6Ra-/- Tregs resulted in severe aggravation of GN in mice. CONCLUSIONS: Our data refine the old paradigm, that IL-6 enhances Th17 responses and suppresses Tregs. We here provide evidence that T cell-intrinsic IL-6Ra classic signaling indeed induces the generation of Th17 cells but at the same time highly immunosuppressive RORγt+ biTregs. These results advocate caution and indicate that IL-6-directed therapies for GN need to be cell-type specific.

Inflammation-Induced IL-6 Functions as a Natural Brake on Macrophages and Limits GN.

IL-6 can mediate proinflammatory effects, and IL-6 receptor (IL-6R) blockade as a treatment for inflammatory diseases has entered clinical practice. However, opposing effects of IL-6 have been observed in models of GN. Although IL-6 is proinflammatory in murine lupus nephritis, protective effects have been observed for IL-6 in the nephrotoxic nephritis (NTN) model of acute crescentic GN. In light of the potential dangers of IL-6-directed treatment, we studied the mechanisms underlying the contradictory findings in GN. IL-6 can signal through the membrane-bound IL-6R, which is expressed only on hepatocytes and certain leukocytes (classic), or through the soluble IL-6R, which binds the ubiquitously expressed gp130 (alternative). Preemptive treatment of mice with anti-IL-6R or anti-IL-6 worsened NTN, whereas selective blockade of alternative IL-6 signaling by the fusion protein sgp130Fc did not. FACS analysis of mouse spleen cells revealed proinflammatory macrophages express the highest levels of IL-6Rα, and in vitro treatment with IL-6 blocked macrophage proliferation. Furthermore, proinflammatory macrophages were expanded during inflammation in IL-6(-/-) mice. Late application of anti-IL-6 after establishment of adaptive nephritogenic immunity was sufficient to aggravate NTN within 2.5 days, a period when macrophages are active. Finally, NTN was aggravated in mice with macrophage-specific impairment of IL-6 classic signaling, coincident with enhanced macrophage proliferation and accumulation in the kidney. Our data thus reveal a novel mechanism in which IL-6-mediated dampening of macrophage activation protects tissues from overshooting immune responses. This finding has important implications for potential IL-6-directed therapies and supports the careful choice of recipient patients and timing.

IL-6 controls the innate immune response against Listeria monocytogenes via classical IL-6 signaling.

The cytokine IL-6 plays a protective role in immune responses against bacterial infections. However, the mechanisms of IL-6-mediated protection are only partially understood. IL-6 can signal via the IL-6R complex composed of membrane-bound IL-6Rα (mIL-6Rα) and gp130. Owing to the restricted expression of mIL-6Rα, classical IL-6 signaling occurs only in a limited number of cells such as hepatocytes and certain leukocyte subsets. IL-6 also interacts with soluble IL-6Rα proteins and these IL-6/soluble IL-6Rα complexes can subsequently bind to membrane-bound gp130 proteins and induce signaling. Because gp130 is ubiquitously expressed, this IL-6 trans-signaling substantially increases the spectrum of cells responding to IL-6. In this study, we analyze the role of classical IL-6 signaling and IL-6 trans-signaling in the innate immune response of mice against Listeria monocytogenes infection. We demonstrate that L. monocytogenes infection causes profound systemic IL-6 production and rapid loss of IL-6Rα surface expression on neutrophils, inflammatory monocytes, and different lymphocyte subsets. IL-6-deficient mice or mice treated with neutralizing anti-IL-6 mAb displayed impaired control of L. monocytogenes infection accompanied by alterations in the expression of inflammatory cytokines and chemokines, as well as in the recruitment of inflammatory cells. In contrast, restricted blockade of IL-6 trans-signaling by application or transgenic expression of a soluble gp130 protein did not restrain the control of infection. In summary, our results demonstrate that IL-6Rα surface expression is highly dynamic during the innate response against L. monocytogenes and that the protective IL-6 function is dependent on classical IL-6 signaling via mIL-6Rα.

Stat3 programs Th17-specific regulatory T cells to control GN.

A pathogenic role for Th17 cells in inflammatory renal disease is well established. The mechanisms underlying their counter-regulation are, however, largely unknown. Recently, Th17 lineage-specific regulatory T cells (Treg17) that depend on activation of the transcription factor Stat3 were identified. We studied the function of Treg17 in the nephrotoxic nephritis (NTN) model of crescentic GN. The absence of Treg17 cells in Foxp3(Cre)×Stat3(fl/fl) mice resulted in the aggravation of NTN and skewing of renal and systemic immune responses toward Th17. Detailed analysis of Stat3-deficient Tregs revealed that the survival, activation, proliferation, and suppressive function of these cells remained intact. However, Tregs from Foxp3(Cre)×Stat3(fl/fl) mice lacked surface expression of the chemokine receptor CCR6, which resulted in impaired renal trafficking. Furthermore, aggravation of NTN was reversible in the absence of Th17 responses, as shown in CD4(Cre)×Stat3(fl/fl) mice lacking both Treg17 and Th17 cells, suggesting that Th17 cells are indeed the major target of Treg17 cells. Notably, immunohistochemistry revealed CCR6-bearing Treg17 cells in kidney biopsy specimens of patients with GN. CCR6 expression on human Treg17 cells also appears dependent on STAT3, as shown by analysis of Tregs from patients with dominant-negative STAT3 mutations. Our data indicate the presence and involvement of Stat3/STAT3-dependent Treg17 cells that specifically target Th17 cells in murine and human crescentic GN, and suggest the kidney-specific action of these Treg17 cells is regulated by CCR6-directed migration into areas of Th17 inflammation.

Short-term TNFα shedding is independent of cytoplasmic phosphorylation or furin cleavage of ADAM17.

Proteolysis of transmembrane molecules is an irreversible post-translational modification enabling autocrine, paracrine and endocrine signaling of many cytokines. The pro-inflammatory activities of membrane bound TNFα (pro-TNFα) strongly depend on ectodomain shedding mediated by the A Disintegrin And Metalloprotease family member ADAM17. Despite the well-documented role of ADAM17 in pro-TNFα cleavage during inflammation, little is known about its regulation. Mitogen-activated protein kinase-induced phosphorylation of the ADAM17 cytoplasmic tail has been described to be required for proper activation. To address, if pro-TNFα shedding depends on cytosolic phosphorylation we analyzed ADAM17 mutants lacking the cytoplasmic domain. ADAM17 mediated shedding of pro-TNFα was induced by PMA, Anisomycin and the phosphatase inhibitors Cantharidin and Calyculin A. Deletion of the entire cytoplasmic portion of ADAM17 abolished furin-dependent proteolytic maturation and pro-TNFα cleavage. Interestingly, we could exclude that resistance to proconvertase processing is the reason for the enzymatic inactivity of ADAM17 lacking the cytoplasmic portion as furin-resistant ADAM17 mutants rescued genetic ADAM17 deficiency after mitogen-activated protein kinase activation. Adding only 6 cytoplasmic amino acids completely restored ADAM17 maturation and shedding of pro-TNFα as well as of both TNF-receptors Finally, we showed that a pro-TNFα mutant lacking the cytoplasmic portion was also shed from the cell surface. We conclude that pro-TNFα cleavage by its major sheddase ADAM17 does not depend on cytosolic phosphorylation and/or interaction. These results have general implications on understanding the activation mechanism controlling the activity of ADAM17.

Early risk stratification in patients with cardiogenic shock irrespective of the underlying cause - the Cardiogenic Shock Score.

AIMS: Early risk stratification is essential to guide treatment in cardiogenic shock (CS). Existing CS risk scores were derived in selected cohorts, without accounting for the heterogeneity of CS. The aim of this study was to develop a universal risk score (the Cardiogenic Shock Score, CSS) for all CS patients, irrespective of the underlying cause. METHODS AND RESULTS: Within a registry of 1308 CS unselected patients admitted to a tertiary care hospital between 2009 and 2019, a Cox regression model was fitted to derive the CSS, with 30-day mortality as main outcome. The CSS's predictive ability was compared to the IABP-SHOCK II score, the CardShock score and SCAI classification by C-indices and validated in an external cohort of 934 CS patients. Based on the Cox regression, nine predictors were included in the CSS: age, sex, acute myocardial infarction (AMI-CS), systolic blood pressure, heart rate, pH, lactate, glucose and cardiac arrest. The CSS had the highest C-index in the overall cohort (0.740 vs. 0.677/0.683 for IABP-SHOCK II score/CardShock score), in patients with AMI-CS (0.738 vs. 0.675/0.689 for IABP-SHOCK II score/CardShock score) and in patients with non-AMI-CS (0.734 vs. 0.677/0.669 for IABP-SHOCK II score/CardShock score). In the external validation cohort, the CSS had a C-index of 0.73, which was higher than all other tested scores. CONCLUSION: The CSS provides improved information on the risk of death in unselected patients with CS compared to existing scores, irrespective of its cause. Because it is based on point-of-care variables which can be obtained even in critical situations, the CSS has the potential to guide treatment decisions in CS.

Sex differences in patients with cardiogenic shock.

AIMS: Differences between female and male patients in clinical presentation, causes and treatment of cardiogenic shock (CS) are poorly understood. We aimed to investigate sex differences in presentation with and treatment of CS. METHODS AND RESULTS: We analysed data of 978 patients presenting with CS to a tertiary care hospital between October 2009 and October 2017. Multivariable adjusted logistic/Cox regression models were fitted to investigate the association between sex and clinical presentation, use of treatments and 30 day mortality. Median age was 70 years (interquartile range 58-79 years), and 295 (30.2%) patients were female. After adjustment for multiple relevant confounders, female patients were more likely to be older [odds ratio (OR) 1.21, 95% confidence interval (CI) 1.02-1.42, P = 0.027], but other relevant presentation characteristics did not differ between both sexes. Despite the similar presentation, female patients were less likely to be treated with percutaneous left ventricular assist devices (OR 0.78, 95% CI 0.64-0.94, P = 0.010), but more likely to be treated with catecholamines (OR 1.21, 95% CI 1.02-1.44, P = 0.033) or vasopressors (OR 1.26, 95% CI 1.05-1.50, P = 0.012). A 30 day mortality risk in female patients was as high as in male patients (hazard ratio 1.08, 95% CI 1.00-1.18, P = 0.091). CONCLUSIONS: In this large, contemporary cohort, clinical presentation was comparable in female and male patients, and both sexes were associated with a comparably high mortality risk. Nevertheless, female patients received different treatment for CS and were most importantly less likely to be treated with percutaneous left ventricular assist devices.

Temporal trends in incidence, causes, use of mechanical circulatory support and mortality in cardiogenic shock.

AIM: The management of cardiogenic shock remains a clinical challenge even in well-developed healthcare systems, best illustrated by its high mortality despite numerous innovative proposals for management. The aim of this study was to describe temporal trends in incidence, causes, use of mechanical circulatory support, and mortality in cardiogenic shock in Germany. METHODS AND RESULTS: Data on all cardiogenic shock patients treated in German hospitals between 2005 and 2017 were obtained from the Federal Bureau of Statistics. The data set comprised 441 696 patients with cardiogenic shock, mean age 71 (±13.8) years, 171 383 (39%) female patients. Incidence rates increased from 33.1/100 000 population in 2005 (27 246 cases) to 51.7/100 000 population in 2017 (42 779 cases). Acute myocardial infarction was the most common cause of cardiogenic shock in 2005-07 (43 422 of 82 037 cases, 52.9%), but the proportion of cases caused by it decreased until 2014-17 (73 274 of 165 873 cases, 44.2%). Over time, intra-aortic balloon pump (2005: 5104; 2017: 973 cases) was used less frequently, whereas use of extracorporeal-membrane-oxygenation (2007: 35; 2017: 2414 cases) and percutaneous left ventricular assist devices (2005: 27; 2017: 1323 cases) increased. Mortality remained high at around 60% without relevant temporal trends in patients without acute myocardial infarction and slightly decreased in patients with acute myocardial infarction. CONCLUSIONS: In this large, nation-wide study, annual incidence of cardiogenic shock was growing, its causes were changing, and mortality was high despite a shift towards use of novel mechanical circulatory support devices. This highlights the need to address the evidence gap in this field, in particular for cardiogenic shock caused by diseases other than acute myocardial infarction.

Eligibility for mechanical circulatory support devices based on current and past randomised cardiogenic shock trials.

AIMS: Mechanical circulatory support devices (MCS) are potentially effective treatments for cardiogenic shock (CS) and are thus evaluated in several randomised controlled trials (RCTs). However, it is not clear how enrolment criteria of these RCTs apply to a real-world CS population. This study aimed to shed light on eligibility to these trials. METHODS AND RESULTS: Pragmatic enrolment criteria for the IABP-SHOCK II, the DanGer-SHOCK, the ECLS-SHOCK and the EURO-SHOCK trials were retrospectively applied to 1305 CS patients admitted to a tertiary care hospital between 2009 and 2019. Based on this, major enrolment criteria were identified and outcome between eligible and ineligible patients was assessed. In this study, 415 (31.8%) patients were eligible for any study. Lowest eligibility was observed for DanGer-SHOCK (11.9%) and the highest for IABP-SHOCK II (26.9%). Over all trials, inclusion criteria were more restrictive than exclusion criteria and absence of CS caused by acute myocardial infarction (AMI) was the primary reason for non-eligibility. However, even in CS caused by AMI, enrolment criteria were only met in 65.4% of patients. Importantly, 30-day mortality was high across all patients/trials, irrespective of eligibility or non-eligibility. CONCLUSION: The present study highlights that current and past RCTs only reflect about a third of the overall CS population. While enrolment criteria are a necessary aspect of RCTs, their application limits generalisability of the trials' findings. More trials on CS sub-populations not represented by current or past trials, e.g. CS not caused by AMI, are needed, especially as mortality is high irrespective of eligibility status.

Patient Characteristics, Treatment and Outcome in Non-Ischemic vs. Ischemic Cardiogenic Shock.

: Aim: Evidence on non-ischemic cardiogenic shock (CS) is scarce. The aim of this study was to investigate differences in patient characteristics, use of treatments and outcomes in patients with non-ischemic vs. ischemic CS. METHODS: Patients with CS admitted between October 2009 and October 2017 were identified and stratified as non-ischemic/ischemic CS based on the absence/presence of acute myocardial infarction. Logistic/Cox regression models were fitted to investigate the association between non-ischemic CS and patient characteristics, use of treatments and 30-day in-hospital mortality. RESULTS: A total of 978 patients were enrolled in this study; median age was 70 (interquartile range 58, 79) years and 70% were male. Of these, 505 patients (52%) had non-ischemic CS. Patients with non-ischemic CS were more likely to be younger and female; were less likely to be active smokers, to have diabetes or decreased renal function, but more likely to have a history of myocardial infarction; and they were more likely to present with unfavorable hemodynamics and with mechanical ventilation. Regarding treatments, patients with non-ischemic CS were more likely to be treated with catecholamines, but less likely to be treated with extracorporeal membrane oxygenation or percutaneous left-ventricular assist devices. After adjustment for multiple relevant confounders, non-ischemic CS was associated with a significant increase in the risk of 30-day in-hospital mortality (hazard ratio 1.14, 95% confidence interval 1.04-1.24, p < 0.01). CONCLUSION: In this large study, non-ischemic CS accounted for more than 50% of all CS cases. Non-ischemic CS was not only associated with relevant differences in patient characteristics and use of treatments, but also with a worse prognosis. These findings highlight the need for effective treatment strategies for patients with non-ischemic CS.

High-Sensitivity Cardiac Troponin I Levels and Prediction of Heart Failure: Results From the BiomarCaRE Consortium.

OBJECTIVES: The aims of this study were to characterize the association of high-sensitivity cardiac troponin I (hs-cTnI) with heart failure (HF), to determine its predictive value beyond classical cardiovascular risk factors (CVRFs) and N-terminal pro-B-type natriuretic peptide, and to derive a relevant cutoff for potential clinical application. BACKGROUND: HF is an important contributor to the overall burden of cardiovascular disease. Early identification of individuals at risk could be beneficial for preventive therapies. METHODS: Based on the Biomarker for Cardiovascular Risk Assessment in Europe consortium, we analyzed individual-level data from 4 prospective population-based cohort studies including 48,455 individuals. Participants with myocardial infarction, HF, and stroke at baseline were excluded. We investigated the value of adding hs-cTnI to CVRFs and N-terminal pro-B-type natriuretic peptide using Cox proportional hazards survival models and for prediction by calculating C-statistics and Brier score. RESULTS: The median age of the study population was 51 years, and the median follow-up time for occurrence of HF was 6.61 years. Cox regression models adjusted for age, sex, and CVRFs revealed a significant association of hs-cTnI with incident HF (hazard ratio: 1.42 per log [ng/l] unit change [95% confidence interval: 1.31 to 1.53]). The best predictive value was achieved in the model with CVRFs (base model) and both biomarkers (C-index = 0.862; 95% confidence interval: 0.841 to 0.882). Optimal hs-cTnI cutoff values of 2.6 ng/l for women and 4.2 ng/l for men were derived for selecting individuals at risk. CONCLUSIONS: In this large dataset from the general population, hs-cTnI could show its independence for the prognosis of HF.

Control of Listeria monocytogenes infection requires classical IL-6 signaling in myeloid cells.

IL-6 is required for the response of mice against Listeria monocytogenes. Control of infection depends on classical IL-6 signaling via membrane IL-6Rα, but IL-6 target cells and protective mechanisms remain unclear. We used mice with IL-6Rα-deficiency in T cells (Il6rafl/fl×CD4cre) or myeloid cells (Il6rafl/fl×LysMcre) to define the role of these cells in IL-6-mediated protection. Abrogation of IL-6Rα in T cells did not interfere with bacteria control and induction of TH1 and CD8+ T-cell responses. IL-6Rα-deficiency in myeloid cells caused significant defects in listeria control. This defect was not associated with reduced recruitment of granulocytes and inflammatory monocytes, and both cell populations were activated and not impaired in cytokine production. However, IL-6Rα-deficient inflammatory monocytes displayed diminished expression of IL-4Rα and of CD38, a protein required for phagocytosis and innate control of listeria. In vitro studies revealed that IL-4 and IL-6 cooperated in induction of CD38. In listeria-infected mice, phagocytic activity of inflammatory monocytes correlated with CD38 expression levels on cells and inflammatory monocytes of Il6rafl/fl×LysMcre mice were significantly impaired in phagocytosis. In conclusion, we demonstrate that inhibition of classical IL-6 signaling in myeloid cells causes alterations in differentiation and function of these cells, which subsequently prevent effective control of L. monocytogenes.

Right ventricular temporal assist device for cardiac recompensation.

In this case report, we discuss treatment of a 66-year-old patient with right heart failure due to chronic left heart failure caused by ischemic cardiomyopathy. We decided to manage this patient by implanting a temporary right ventricular assist device (Impella RP®) as a novel therapeutic option for acute on chronic right heart decompensation.

ADAM17 controls IL-6 signaling by cleavage of the murine IL-6Rα from the cell surface of leukocytes during inflammatory responses.

The cytokine IL-6 is part of a regulatory signaling network that controls immune responses. IL-6 binds either to the membrane-bound IL-6 receptor-α (classic signaling) or to the soluble IL-6 receptor-α (trans-signaling) to initiate signal transduction via gp130 activation. Because classic and trans-signaling of IL-6 fulfill different tasks during immune responses, controlled shedding of the membrane-bound IL-6 receptor-α from the surface of immune cells can be considered a central regulator of IL-6 function. The results from cell culture-based experiments have implicated both a disintegrin and metalloprotease 10 and a disintegrin and metalloprotease 17 in IL-6 receptor-α shedding. However, the nature of the protease mediating IL-6 receptor-α release in vivo is not yet known. We used hypomorphic a disintegrin and metalloprotease 17 mice and conditional a disintegrin and metalloprotease 10 knock-out mice to identify the natural protease of the murine IL-6 receptor-α. Circulating homeostatic soluble IL-6 receptor-α levels are not dependent on a disintegrin and metalloprotease 10 or 17 activity. However, during Listeria monocytogenes infection, IL-6 receptor-α cleavage by the α-secretase a disintegrin and metalloprotease 17 is rapidly induced from the surface of different leukocyte populations. In contrast, CD4-Cre-driven a disintegrin and metalloprotease 10 deletion in T cells did not influence IL-6 receptor-α shedding from these cells after L. monocytogenes infection. A disintegrin and metalloprotease 17 was also required for IL-6 receptor-α ectodomain cleavage and release during endotoxemia. These results demonstrate a novel physiologic role for a disintegrin and metalloprotease 17 in regulating murine IL-6 signals during inflammatory processes.