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Kim J.-Y.,Catholic Research Institutes of Medical Science | Park Y.-J.,Catholic University of Korea | Kim K.-J.,Catholic University of Korea | Choi J.-J.,Korea University | And 3 more authors.
Arthritis and Rheumatism | Year: 2013

Objective Elevated serum osteoprotegerin (OPG) levels represent an independent risk factor for atherosclerotic disease, although the underlying mechanism is not clear. The aim of this study was to investigate the association of serum OPG levels and circulating endothelial progenitor cell (EPC) numbers, and to explore the effect of OPG on EPC apoptosis and its underlying mechanisms. Methods Flow cytometry was used to enumerate EPCs in the peripheral blood of 91 patients with systemic lupus erythematosus (SLE). Cultured EPCs, isolated from peripheral blood, were challenged with OPG, and apoptosis was evaluated by TUNEL staining. Expression of apoptosis-related proteins was measured by real-time quantitative polymerase chain reaction (qPCR) and Western blotting. Reactive oxygen species (ROS) were detected by flow cytometry, and the expression of NADPH oxidase (NOX) and MAP kinases (MAPK) was measured by qPCR and Western blotting. Results The serum OPG level was independently associated with reduced numbers of EPCs in patients with SLE. In vitro treatment with OPG significantly induced apoptosis of EPCs; this effect was mediated by syndecan 4. OPG-induced apoptosis was abolished by the ROS scavenger N-acetylcysteine and the NOX inhibitor diphenyleniodonium. OPG increased ROS production through activation of NOX-2 and NOX-4 and triggered phosphorylation of ERK-1/2 and p38 MAPK. Quenching of ROS by knockdown of NOX-2 or NOX-4 transcripts inhibited phosphorylation of ERK-1/2 and p38 MAPK. Moreover, inhibitors of ERK-1/2 and p38 MAPK decreased ROS production and subsequent EPC apoptosis, indicating a feed-forward loop between NOX and MAPK to amplify ROS production related to apoptosis. Conclusion Elevated OPG levels increase apoptosis of EPCs by induction of oxidative stress. Copyright © 2013 by the American College of Rheumatology. Source


Jung Y.-E.,Catholic University of Korea | Min J.-A.,Catholic University of Korea | Shin A.Y.,Catholic Research Institutes of Medical Science | Han S.Y.,Catholic Research Institutes of Medical Science | And 12 more authors.
Stress and Health | Year: 2012

The Connor-Davidson Resilience Scale (CD-RISC) is a brief self-rating questionnaire for measuring resilience. The aims of the present study were to describe the development of a Korean version of the CD-RISC (K-CD-RISC) and to more firmly establish its psychometric properties in terms of reliability and validity. The participants consisted of a general population sample (n = 194) and psychiatric outpatients (n = 127) with non-psychotic mood or anxiety disorders. The K-CD-RISC score means (standard deviation) were 65.9 (13.6) in the general population and 50.4 (20.5) in the psychiatric outpatients. The mean score of the general population was significantly higher than that of the psychiatric outpatients. Exploratory factor analysis revealed five factors, and the obtained factor structure was verified through confirmatory factor analysis. In the general population, the Cronbach's α coefficient of the K-CD-RISC was found to be 0.92. Greater resilience was found to be associated with less perceived stress, anxiety and depression and with higher levels of positive affect and purpose in life. Taken together, our findings suggest that the K-CD-RISC has good psychometric properties and is a valid and reliable tool for assessing resilience. Copyright © 2011 John Wiley & Sons, Ltd. Source

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