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.

Valores seriados de galectina-3 a corto plazo en pacientes hospitalizados por insuficiencia cardiaca aguda / Short-term serial measurement of galectin-3 in hospitalized patients with acute heart failure

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Involvement of ferritin heavy chain in the preventive effect of metformin against doxorubicin-induced cardiotoxicity.

Doxorubicin is a wide-spectrum chemotherapeutic agent, although a cumulative dose may cause cardiac damage and lead to heart failure. Doxorubicin cardiotoxicity is dependent on the intracellular iron pool and manifests itself by increasing oxidative stress. Our group has recently shown the ability of metformin, an oral antidiabetic with cardiovascular benefits, to protect cardiomyocytes from doxorubicin-induced damage. This work aimed to study whether metformin is able to modulate the expression of ferritin, the major intracellular iron storage protein, in cardiomyocytes and whether it is involved in their protection. The addition of metformin to adult mouse cardiomyocytes (HL-1 cell line) induced both gene and protein expression of the ferritin heavy chain (FHC) in a time-dependent manner. The silencing of FHC expression with siRNAs inhibited the ability of metformin to protect cardiomyocytes from doxorubicin-induced damage, in terms of the percentage of cell viability, the levels of reactive oxygen species, and the activity of antioxidant enzymes (catalase, glutathione peroxidase, and superoxide dismutase). In addition, metformin induced the activation of NF-κB in HL-1 cells, whereas preincubation with SN50, an inhibitor of NF-κB, blocked the upregulation of the FHC and the protective effect mediated by metformin. Taken together, these results provide new knowledge on the protective actions of metformin against doxorubicin-induced cardiotoxicity by identifying FHC and NF-κB as the major mediators of this beneficial effect.