The Interleukin-1 Axis and Risk of Death in Patients With Acutely Decompensated Heart Failure.

BACKGROUND: Soluble ST2 (sST2), which is the soluble form of interleukin (IL)-1 receptor-like 1, identifies risk in acutely decompensated heart failure (ADHF). IL-1ß is an inflammatory cytokine that has deleterious effects in myocardial remodeling and function. IL-1ß inhibition has beneficial effects after acute myocardial infarction. However, the role of IL-1ß in ADHF and its relationship to ST2 remain unclear. OBJECTIVES: This study sought to investigate the relationship between IL-1ß and sST2, and the prognostic impact of such a relationship in patients with ADHF. METHODS: This study examined 316 consecutive patients who were hospitalized with ADHF (72 ± 12 years of age, 57% male, and left ventricular ejection fraction 45 ± 17%). Blood samples were collected at presentation, and IL-1ß and sST2 levels were measured. All-cause mortality was obtained for all patients at 1 year. RESULTS: The IL-1ß concentration at presentation was associated with prior HF hospitalizations, functional impairment, and higher N-terminal pro-B-type natriuretic peptide and high-sensitivity troponin T concentrations. IL-1ß was higher in patients who died during the year after hospitalization (n = 52, 16.5%) (p = 0.005), and the optimal threshold was identified with levels over 49.1 pg/ml (hazard ratio: 2.5; 95% confidence interval: 1.43 to 4.49; p = 0.0014). Circulating IL-1ß positively correlated with sST2 (ρ = 0.65; p < 0.001). Considering the prognostic thresholds of IL-1ß (≥49.1 pg/ml) and sST2 (≥35.0 ng/ml) concentrations: all patients with low sST2 also presented with low IL-1ß; among patients with high sST2, only those with also high IL-1ß had a significantly higher risk of death (30% vs. 14%; hazard ratio: 2.52; 95% confidence interval: 1.40 to 4.56; p = 0.002). CONCLUSIONS: Circulating IL-1ß concentrations are clinically meaningful in ADHF patients and interplay with the predictive ability of sST2. IL-1 axis-related inflammation signaling may represent a therapeutic target in ADHF.

Pulmonary Production of Soluble ST2 in Heart Failure.

BACKGROUND: Serum concentrations of ST2 (interleukin-1 receptor-like 1) represent a meaningful prognostic marker in cardiac diseases. Production of soluble ST2 (sST2) may be partially extracardiac. Identification of sST2 sources is relevant to design strategies for modulating its signaling. METHODS AND RESULTS: An experimental model of ischemic heart failure was used. sST2, membrane-bound ST2 (ST2L), and IL-33 were measured in lungs, heart, kidney, and liver by quantifying mRNA and protein expression in tissue samples obtained at different times (1, 2, 4, and 24 weeks). Primary human type II pneumocyte cell cultures were subjected to strain. sST2 was measured in samples of bronchial aspirate and serum obtained from patients treated with invasive respiratory support. In the experimental model, sST2 increased significantly from the first week in both lungs and myocardium, whereas ST2L/IL-33 response was unfavorable in lungs (decrease) and favorable in myocardium (increase). No changes were observed in liver and kidneys. ST2 immunostaining was intensely observed in alveolar epithelium, and sST2 was secreted by primary human type II pneumocytes in response to strain. sST2 levels in lung aspirates were substantially higher in the presence of cardiogenic pulmonary edema (median, 228 [interquartile range, 28.4-324.0] ng/mL; P<0.001) than bronchopneumonia (median, 5.5 [interquartile range, 1.6-6.5]) or neurological disorders (median, 2.9 [interquartile range, 1.7-10.1]), whereas sST2 concentrations in serum did not differ. CONCLUSIONS: The lungs are a relevant source of sST2 in heart failure. These results may have implications for the progression of disease and the development of therapies targeting the ST2 system in patients with heart failure.

Mineralocorticoid receptor antagonists modulate galectin-3 and interleukin-33/ST2 signaling in left ventricular systolic dysfunction after acute myocardial infarction.

OBJECTIVES: This study aimed to evaluate the specific role of the 2 available mineralocorticoid receptor antagonists (MRAs), eplerenone and spironolactone, on the modulation of galectin-3 (Gal-3) and interleukin (IL)-33/ST2 signaling in an experimental model of left ventricular systolic dysfunction after acute myocardial infarction (MI). BACKGROUND: The molecular mechanisms of benefits of MRAs in patients with left ventricular systolic dysfunction after MI not well understood. METHODS: MI and left ventricular systolic dysfunction were induced by permanent ligation of the anterior coronary artery in 45 male Wistar rats, randomly assigned to no therapy (MI group, n = 15) or to receive MRAs (100 mg/kg/day) for 4 weeks; either eplerenone (n = 15) or spironolactone (n = 15) was used. A sham group was used as a control (n = 8). Elements of the pathway for Gal-3 including transforming growth factor (TGF)-ß and SMAD3, as well as that for IL-33/ST2 (including IL-33 and soluble ST2 [sST2]) were analyzed in the infarcted and noninfarcted myocardium by quantitative real-time reverse transcription polymerase chain reaction. Expression of markers of fibrosis (collagen types I and III, tissue inhibitor of metalloproteinase-1) and inflammation (IL-6, tumor necrosis factor-α, monocyte chemotactic protein-1) was also examined. RESULTS: In the infarcted myocardium, compared with sham animals, the MI group had higher concentrations of Gal-3, TGF-ß, SMAD3, IL-33, and sST2, as well as higher concentrations of markers of fibrosis and inflammation. Treatment with MRAs down-regulated Gal-3, TGF-ß, and SMAD3 and enhanced IL-33/ST2 signaling with lower expression of sST2; protective IL-33 up-regulation was unaffected by MRAs. Modulation of Gal-3 and IL-33/ST2 signaling induced by MRAs correlated with lower expression levels of fibrosis and inflammatory markers. No differences were found between eplerenone and spironolactone. In the noninfarcted myocardium, compared with sham animals, the MI group exhibited a higher expression of Gal-3 and IL-33, but no signs of inflammation or fibrosis were observed; in the presence of MRAs, IL-33 expression was significantly up-regulated, but Gal-3 was unaffected. CONCLUSIONS: MRAs play a pivotal role in the Gal-3 and IL-33/ST2 modulation in post-MI cardiac remodeling.