Clinical and Angiographic Features of Patients With Out-of-Hospital Cardiac Arrest and Acute Myocardial Infarction.

BACKGROUND: Sudden cardiac arrest is a serious complication of acute myocardial infarction (MI). Although in-hospital mortality from MI has decreased, the mortality of MI patients complicated with out-of-hospital cardiac arrest (OHCA) remains high. However, the features of acute MI patients with OHCA have not been well known. OBJECTIVES: We sought to characterize the clinical and angiographic features of acute MI patients with OHCA comparing with those without OHCA. METHODS: We retrospectively analyzed 480 consecutive patients with acute MI undergoing percutaneous coronary intervention. Patients complicated with OHCA were compared with patients without OHCA. RESULTS: Of the patients, 141 (29%) were complicated with OHCA. Multivariate analysis revealed that age (odds ratio [OR]: 0.8; 95% confidence interval [CI]: 0.7 to 0.9 per 5 years; p < 0.001), estimated glomerular filtration rate (OR: 0.8; 95% CI: 0.7 to 0.8 per 10 ml/min/1.73 m2; p < 0.001), peak creatine kinase-myocardial band (OR: 1.3; 95% CI: 1.2 to 1.4 per 102 U/l; p < 0.001), calcium-channel antagonists use (OR: 0.4; 95% CI: 0.2 to 0.7; p = 0.002), the culprit lesion at the left main coronary artery (OR: 5.3; 95% CI: 1.9 to 15.1; p = 0.002), and the presence of chronic total occlusion (OR: 2.9; 95% CI: 1.5 to 5.7; p = 0.001) were significantly associated with OHCA. CONCLUSIONS: Younger age, no use of calcium-channel antagonists, worse renal function, larger infarct size, culprit lesion in the left main coronary artery, and having chronic total occlusion were associated with OHCA.

Endogenous metalloprotease solubilizes IL-13 receptor alpha2 in airway epithelial cells.

IL-13 receptor alpha2 (IL-13Ralpha2) has been postulated to be a decoy receptor. The precise mechanisms for the generation of soluble IL-13Ralpha2 and the biological activity of the endogenous soluble form have not been reported. Hypothesizing that the soluble form of IL-13Ralpha2 is generated by proteolytic cleavage of membrane-bound receptors, we transfected human airway epithelial cells with adenoviral vectors encoding full-length IL-13Ralpha2. Eotaxin production from IL-13Ralpha2-transfected cells was suppressed, and soluble IL-13Ralpha2 in the supernatants was increased time-dependently after the transfection. The transfer of conditioned media from IL-13Ralpha2-transfected cells inhibited IL-13-induced eotaxin production and STAT6 phosphorylation in non-transfected cells. PMA enhanced the release of soluble IL-13Ralpha2, and metalloprotease inhibitors inhibited this release. These findings suggest that airway epithelial cells with upregulation of membrane-bound IL-13Ralpha2 secrete soluble IL-13Ralpha2 into its supernatant, causing the autocrine and paracrine downregulation of the IL-13/STAT6 signal. Metalloprotease(s) are responsible for the proteolytic cleavage of cell surface IL-13Ralpha2.

Niflumic acid suppresses interleukin-13-induced asthma phenotypes.

RATIONALE: Chloride channels have been implicated in the regulation of mucus production in epithelial cells. Expression of hCLCA1, a calcium-activated chloride channel, has been reported to be increased in the airway epithelium of patients with asthma. Interleukin (IL)-13 induces the cardinal features of bronchial asthma, and glucocorticoids are not sufficient to suppress IL-13-induced airway hyperresponsiveness or goblet cell hyperplasia. OBJECTIVES: We studied the effects of chloride channel inhibitors in IL-13-induced asthma. METHODS: The effects of niflumic acid (NA), a relatively specific blocker of calcium-activated chloride channel (CLCA), on goblet cell hyperplasia, eosinophil accumulation, and airway hyperresponsiveness were evaluated after IL-13 instillation into the airways. Because IL-13-dependent features rely on JAK/STAT6 signaling, the effect of NA on phosphorylation of JAK2 and STAT6 after IL-13 stimulation was examined in airway epithelial cells in vitro. The expression of the mCLCA family in mouse lung after IL-13 local administration in vivo was analyzed using reverse transcription-polymerase chain reaction. MEASUREMENTS AND MAIN RESULTS: Treatment with NA inhibited not only IL-13-induced goblet cell hyperplasia but also airway hyperresponsiveness and eosinophilic infiltration. NA suppressed the eotaxin levels in bronchoalveolar lavage fluids and overexpression of the MUC5AC gene, a marker of goblet cell hyperplasia, in the lung after IL-13 instillation. NA suppressed JAK2 activation, STAT6 activation, and eotaxin expression in epithelial cells. The expression of mCLCA3 (mouse homolog hCLCA1), but not that of other CLCA family members, was up-regulated by IL-13. CONCLUSIONS: These findings suggest that a chloride channel inhibitor can control IL-13-mediated airway features at least by suppressing JAK/STAT6 activation.

Expression of B7-H1 and B7-DC on the airway epithelium is enhanced by double-stranded RNA.

Viral infection in the airway provokes various immune responses, including Th1 and Th2 responses, which are partly initiated by double-stranded RNA (dsRNA), a viral product for its replication. B7-H1 (PD-L1) and B7-DC (PD-L2) are B7-family molecules that bind to programmed death-1 (PD-1) on lymphocytes and are implicated in peripheral tolerance. We investigated the effect of dsRNA on the expression of B7-H1 and B7-DC on airway epithelial cell lines. B7-H1 and B7-DC were constitutively expressed on the cells, and their expression was profoundly upregulated by stimulation with an analog of viral dsRNA, polyinosinic-polycytidylic acid. B7-H1 and B7-DC were also upregulated by stimulation with IFN-gamma, IL-13, and the supernatant from T cell clones. A relatively high concentration of dexamethasone (1 microM) was required to suppress the upregulation of B7-H1 or B7-DC. These results suggest that epithelial B7-H1 and B7-DC play a role in virus-associated immune responses in the airways.