Erik T. Askevold

The NLRP3 inflammasome is up-regulated in cardiac fibroblasts and mediates myocardial ischaemia–reperfusion injury

AIMS Nucleotide-binding oligomerization domain-Like Receptor with a Pyrin domain 3 (NLRP3) is considered necessary for initiating a profound sterile inflammatory response. NLRP3 forms multi-protein complexes with Apoptosis-associated Speck-like protein containing a Caspase recruitment domain (ASC) and Caspase-1, which activate pro-interleukin-1β (IL-1β) and pro-IL-18. The role of NLRP3 in cardiac cells is not known. Thus, we investigated the expression and function of NLRP3 during myocardial ischaemia. METHODS AND RESULTS Myocardial infarction (MI) was induced in adult C57BL/6 mice and Wistar rats by ligation of the coronary artery. A marked increase in NLRP3, IL-1β, and IL-18 mRNA expression was found in the left ventricle after MI, primarily located to myocardial fibroblasts. In vitro studies in cells from adult mice showed that myocardial fibroblasts released IL-1β and IL-18 when primed with lipopolysaccharide and subsequently exposed to the danger signal adenosine triphosphate, a molecule released after tissue damage during MI. When hearts were isolated from NLRP3-deficient mice, perfused and subjected to global ischaemia and reperfusion, a marked improvement of cardiac function and reduction of hypoxic damage was found compared with wild-type hearts. This was not observed in ASC-deficient hearts, potentially reflecting a protective role of other ASC-dependent inflammasomes or inflammasome-independent effects of NLRP3. CONCLUSION This study shows that the NLRP3 inflammasome is up-regulated in myocardial fibroblasts post-MI, and may be a significant contributor to infarct size development during ischaemia-reperfusion.

The association between neutrophil gelatinase-associated lipocalin and clinical outcome in chronic heart failure: results from CORONA*.

Abstract.  Nymo SH, Ueland T, Askevold ET, Flo TH, Kjekshus J, Hulthe J, Wikstrand J, McMurray J, Van Veldhuisen DJ, Gullestad L, Aukrust P, Yndestad A (Oslo University Hospital Rikshospitalet; University of Oslo; Oslo; Norwegian University of Technology and Science, Trondheim, Norway; Gothenburg University, Gothenburg; AstraZeneca, Mölndal, Sweden; University of Glasgow, UK; and University Medical Center Groningen, University of Groningen, The Netherlands). The association between neutrophil gelatinase‐associated lipocalin and clinical outcome in chronic heart failure: results from CORONA. J Intern Med 2012; 271: 436–443.

Lumican is increased in experimental and clinical heart failure, and its production by cardiac fibroblasts is induced by mechanical and proinflammatory stimuli

During progression to heart failure (HF), myocardial extracellular matrix (ECM) alterations and tissue inflammation are central. Lumican is an ECM‐localized proteoglycan associated with inflammatory conditions and known to bind collagens. We hypothesized that lumican plays a role in the dynamic alterations in cardiac ECM during development of HF. Thus, we examined left ventricular cardiac lumican in a mouse model of pressure overload and in HF patients, and investigated expression, regulation and effects of increased lumican in cardiac fibroblasts. After 4 weeks of aortic banding, mice were divided into groups of hypertrophy (AB) and HF (ABHF) based on lung weight and left atrial diameter. Sham‐operated mice were used as controls. Accordingly, cardiac lumican mRNA and protein levels were increased in mice with ABHF. Similarly, cardiac biopsies from patients with end‐stage HF revealed increased lumican mRNA and protein levels compared with control hearts. In vitro, mechanical stretch and the proinflammatory cytokine interleukin‐1β increased lumican mRNA as well as secreted lumican protein from cardiac fibroblasts. Stimulation with recombinant glycosylated lumican increased collagen type I alpha 2, lysyl oxidase and transforming growth factor‐β1 mRNA, which was attenuated by costimulation with an inhibitor of the proinflammatory transcription factor NFκB. Furthermore, lumican increased the levels of the dimeric form of collagen type I, decreased the activity of the collagen‐degrading enzyme matrix metalloproteinase‐9 and increased the phosphorylation of fibrosis‐inducing SMAD3. In conclusion, cardiac lumican is increased in experimental and clinical HF. Inflammation and mechanical stimuli induce lumican production by cardiac fibroblasts and increased lumican altered molecules important for cardiac remodeling and fibrosis in cardiac fibroblasts, indicating a role in HF development.

Inflammatory cytokines in chronic heart failure: interleukin-8 is associated with adverse outcome: results from CORONA

We investigated the ability of prototypical inflammatory cytokines to predict clinical outcomes in a large population of patients with chronic systolic heart failure (HF).

Innate immune signaling induces expression and shedding of the heparan sulfate proteoglycan syndecan-4 in cardiac fibroblasts and myocytes, affecting inflammation in the pressure-overloaded heart.

Sustained pressure overload induces heart failure, the main cause of mortality in the Western world. Increased understanding of the underlying molecular mechanisms is essential to improve heart failure treatment. Despite important functions in other tissues, cardiac proteoglycans have received little attention. Syndecan‐4, a transmembrane heparan sulfate proteoglycan, is essential for pathological remodeling, and we here investigated its expression and shedding during heart failure. Pressure overload induced by aortic banding for 24 h and 1 week in mice increased syndecan‐4 mRNA, which correlated with mRNA of inflammatory cytokines. In cardiac myocytes and fibroblasts, tumor necrosis factor‐α, interleukin‐1β and lipopolysaccharide through the toll‐like receptor‐4, induced syndecan‐4 mRNA. Bioinformatical and mutational analyses in HEK293 cells identified a functional site for the proinflammatory nuclear factor‐κB transcription factor in the syndecan‐4 promoter, and nuclear factor‐κB regulated syndecan‐4 mRNA in cardiac cells. Interestingly, tumor necrosis factor‐α, interleukin‐1β and lipopolysaccharide induced nuclear factor‐κB‐dependent shedding of the syndecan‐4 ectodomain from cardiac cells. Overexpression of syndecan‐4 with mutated enzyme‐interacting domains suggested enzyme‐dependent heparan sulfate chains to regulate shedding. In cardiac fibroblasts, lipopolysaccharide reduced focal adhesion assembly, shown by immunohistochemistry, suggesting that inflammation‐induced shedding affects function. After aortic banding, a time‐dependent cardiac recruitment of T lymphocytes was observed by measuring CD3, CD4 and CD8 mRNA, which was reduced in syndecan‐4 knockout hearts. Finally, syndecan‐4 mRNA and shedding were upregulated in failing human hearts. Conclusively, our data suggest that syndecan‐4 plays an important role in the immune response of the heart to increased pressure, influencing cardiac remodeling and failure progression.

Disturbed carnitine regulation in chronic heart failure — Increased plasma levels of palmitoyl-carnitine are associated with poor prognosis

BACKGROUND/OBJECTIVES Heart failure is characterized by disturbed energy metabolism and impaired mitochondrial function. L-carnitine plays a critical role in fatty acid transport into the mitochondria and may thus influence inflammation and myocardial function. The aim of this study was to investigate carnitine metabolism in relation to progression of heart failure (HF). METHODS AND RESULTS We examined plasma levels of free L-carnitine as well as several of its precursors and derivates in HF patients (n=183) and matched healthy controls (n=111) as well as their relationship with cardiac dysfunction as assessed by echocardiographic measurements, inflammation (CRP) and neurohormonal activation (NT-proBNP) in addition to the prognostic value of carnitine derivates in relation to mortality in these patients. High levels of the carnitine derivates acetyl-carnitine and in particular palmitoyl-carnitine were associated with the degree of HF as evaluated by clinical (NYHA functional class) and neurohormonal assessments. Moreover, plasma levels of palmitoyl-carnitine were associated with serious adverse events (i.e., all-cause mortality and heart transplantation) during follow-up, independently of more established risk markers such as CRP and NT-proBNP, when analyzed by cox-regression and continous net reclassification improvement, but not c-statistics. CONCLUSIONS Our findings support a role for disturbed carnitine metabolism in the pathogenesis of HF, and suggest that some of its derivates could give prognostic information in these patients.

Soluble Glycoprotein 130 Predicts Fatal Outcomes in Chronic Heart Failure Analysis From the Controlled Rosuvastatin Multinational Trial in Heart Failure (CORONA)

Background— Glycoprotein 130 (gp130) is the common signal-transducing receptor subunit of the interleukin-6 (IL-6) family, which may be involved in the progression of heart failure (HF). We hypothesized that soluble gp130 would provide prognostic information beyond that of IL-6 in a population with HF from the Controlled Rosuvastatin Multinational Trial in Heart Failure (CORONA). Methods and Results— The associations of soluble gp130 and IL-6 with morbidity, mortality, and mode of death were assessed by immunoassays in a subset of 1452 patients enrolled in the CORONA trial, which included patients with HF, aged ≥60 years, in New York Heart Association classes II to IV, who had ischemic heart disease and a reduced left ventricular ejection fraction. In multivariable analyses, including C-reactive protein, IL-6, troponin T, and N-terminal pro-B-type natriuretic peptide, elevated soluble gp130 (fifth quintile versus all lower quintiles) was associated with all-cause mortality (hazard ratio, 1.47 [1.11–1.93]; P =0.006), cardiovascular mortality (hazard ratio, 1.38 [1.01–1.87]; P =0.042), and death from worsening HF (hazard ratio, 1.85 [1.09–3.14]; P =0.002), but not with the primary end point (composite of death from cardiovascular causes, nonfatal myocardial infarction, and nonfatal stroke; hazard ratio, 1.12 [0.84–1.50]; P =0.44). Plasma IL-6 was not associated with outcomes in multivariable analyses. Conclusions— Marked elevations in soluble gp130 are associated with total and cardiovascular mortality, as well as deaths from worsening HF, in elderly patients with HF of ischemic cause Clinical Trial Registration— URL: . Unique identifier: [NCT00206310][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00206310&atom=%2Fcirchf%2F6%2F1%2F91.atomBackground— Glycoprotein 130 (gp130) is the common signal-transducing receptor subunit of the interleukin-6 (IL-6) family, which may be involved in the progression of heart failure (HF). We hypothesized that soluble gp130 would provide prognostic information beyond that of IL-6 in a population with HF from the Controlled Rosuvastatin Multinational Trial in Heart Failure (CORONA). Methods and Results— The associations of soluble gp130 and IL-6 with morbidity, mortality, and mode of death were assessed by immunoassays in a subset of 1452 patients enrolled in the CORONA trial, which included patients with HF, aged ≥60 years, in New York Heart Association classes II to IV, who had ischemic heart disease and a reduced left ventricular ejection fraction. In multivariable analyses, including C-reactive protein, IL-6, troponin T, and N-terminal pro-B-type natriuretic peptide, elevated soluble gp130 (fifth quintile versus all lower quintiles) was associated with all-cause mortality (hazard ratio, 1.47 [1.11–1.93]; P=0.006), cardiovascular mortality (hazard ratio, 1.38 [1.01–1.87]; P=0.042), and death from worsening HF (hazard ratio, 1.85 [1.09–3.14]; P=0.002), but not with the primary end point (composite of death from cardiovascular causes, nonfatal myocardial infarction, and nonfatal stroke; hazard ratio, 1.12 [0.84–1.50]; P=0.44). Plasma IL-6 was not associated with outcomes in multivariable analyses. Conclusions— Marked elevations in soluble gp130 are associated with total and cardiovascular mortality, as well as deaths from worsening HF, in elderly patients with HF of ischemic cause Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00206310.

Increased Systemic and Local Interleukin 9 Levels in Patients with Carotid and Coronary Atherosclerosis

Objective Atherosclerosis is a chronic inflammatory disorder that involves a range of inflammatory mediators. Although interleukin (IL)-9 has been related to inflammation, there are at present no data on its role in atherosclerosis. Here we have examined IL-9 and IL-9 receptor (IL-9R) systemically and locally in patients with coronary and carotid atherosclerosis. Methods Plasma IL-9 was quantified by enzyme immunoassay and multiplex technology. IL-9 and IL-9R mRNA were quantified by real-time RT-PCR, and their localization within the lesion was assessed by immunohistochemistry. Results The main findings were: (i) Patients with carotid atherosclerosis had significantly raised IL-9 plasma levels compared with healthy controls (n = 28), with no differences between asymptomatic (n = 56) and symptomatic (n = 88) patients. (ii) On admission, patients with acute ST-elevation myocardial infarction (STEMI) (n = 42) had markedly raised IL-9 plasma levels which gradually declined during the first week post-MI. (iii) T cells and monocytes from patients with unstable angina (n = 17) had increased mRNA levels of IL-9 as compared with controls (n = 11). (iv) Carotid plaques (n = 68) showed increased mRNA levels of IL-9 and IL-9R compared to non-atherosclerotic vessels (n = 10). Co-localization to T cells (IL-9 and IL-9R) and macrophages (IL-9) were shown by immunohistochemistry. (v) IL-9 increased IL-17 release in peripheral blood mononuclear cells from patients with unstable angina (n = 5) and healthy controls (n = 5) with a particularly enhancing effect in cells from the patient group. Conclusion Our findings show increased IL-9 levels in different atherosclerotic disorders both systemically and within the lesion, suggesting a role for the IL-9/IL-9R axis in the atherosclerotic process, potentially involving IL-17 mediated mechanisms. However, the functional consequences of these findings should be further investigated.

Prognostic Effect of High-Sensitive Troponin T Assessment in Elderly Patients With Chronic Heart Failure Results From the CORONA Trial

Background— The incremental prognostic value of high-sensitive troponin T (hs-cTnT) in heart failure (HF) beyond that of high-sensitivity C-reactive protein and amino-terminal probrain natriuretic peptide is debated. We examined the prognostic value of hs-cTnT in a subgroup of patients from the Controlled Rosuvastatin Multinational Trial in HF (CORONA) study. Methods and Results— Hs-cTnT as a risk factor for the primary end point (cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke; n=356), as well as all-cause mortality (n=366), cardiovascular mortality (n=299), and the composite of cardiovascular mortality and hospitalization from worsening of HF (n=465), was investigated in 1245 patients (≥60 years; New York Heart Association [NYHA] class II–IV, ischemic systolic HF) randomly assigned to 10 mg rosuvastatin or placebo. In multivariable analyses, adjusting for left ventricular ejection fraction, NYHA class, age, body mass index, diabetes mellitus, sex, intermittent claudication, heart rate, estimated glomerular filtration rate, apolipoprotein B/apolipoprotein A-1 ratio, amino-terminal probrain natriuretic peptide, high-sensitivity C-reactive protein, and hs-cTnT (both dichotomized according to the 99th percentile and as a continuous variable) was associated with all end points (primary end point: hazard ratio, 1.87 and 1.51, respectively, per SD change; P<0.001; all other end points: hazard ratio, 1.39–1.70). However, improved discrimination as assessed by C-statistics was only seen for the primary end point and all-cause mortality. Conclusions— Elevated hs-cTnT levels provide strong and independent prognostic information in older patients with chronic ischemic HF. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00206310.

Secreted Wnt Modulators in Symptomatic Aortic Stenosis

Background Valve calcification and inflammation play key roles in the development of aortic stenosis (AS). The Wnt pathways have been linked to inflammation, bone metabolism, angiogenesis, and heart valve formation. We hypothesized that soluble Wnt modulators may be dysregulated in symptomatic AS. Methods and Results We measured circulating levels (n=136) and aortic valve tissue expression (n=16) of the secreted Wnt modulators secreted frizzled related protein-3, dickkopf-1 (DKK-1), and Wnt inhibitory factor-1 (WIF-1) by enzyme immunoassay, immunostaining, and RT-PCR in patients with symptomatic, severe AS and investigated associations with echocardiographic parameters of AS and cardiac function. Finally, we assessed the prognostic value of these Wnt modulators in relation to all-cause mortality (n=35) during long-term follow-up (median 4.6 years; survivors, 4.8 years; nonsurvivors, 1.9 years) in these patients. Our main findings were: (1) serum levels of all Wnt modulators were markedly elevated in patients with symptomatic AS (mean increase 231% to 278%, P<0.001), (2) all Wnt modulators were present in calcified aortic valves but correlated poorly with systemic levels or degree of AS, (3) some modulators (ie, WIF-1) were associated with the degree of myocardial function and valvular calcification, (4) all Wnt modulators, and DKK-1 in particular, predicted long-term mortality in these patients also after adjusting for conventional predictors including NT-proBNP. Conclusions Together, these in vivo data support the involvement of Wnt signaling in the development of AS and suggest that circulating Wnt modulators should be further investigated as risk markers in larger AS populations, including patients with asymptomatic disease.