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엄영우,정하윤,오지은,이준원,안민수,윤영진,안성균,김장영,이승환,윤정한,유병수 대한심장학회 2016 Korean Circulation Journal Vol.46 No.1
Background and Objectives: Chronic impairment of β-adrenergic receptor signaling increases cardiac apoptosis, hypertrophy and fibrosis. The aim of this study was to investigate whether isoproterenol (ISO), an agonist of the adrenergic receptor, can enhance tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in human embryonic kidney (HEK) 293 cells. Materials and Methods: HEK 293 cells were treated with ISO and/or TRAIL for 24 hours. Cell viability was evaluated by microscopy and an established viability assay, and apoptotic cell death was analyzed by staining with fluorescein isothiocynate-annexin-V/propidium iodide (PI) and caspase activation. To confirm the mechanism of cell death induced by co-treatment with ISO and TRAIL, expression of TRAIL receptor 2 (death receptor 5, DR5) was evaluated by immunoblotting. Results: Although ISO or TRAIL treatment decreased HEK 293 cell viability by 13% and 17%, respectively, co-treatment with ISO and TRAIL resulted in a markedly higher death rate of 35% after 24 hours. Increases were evident in early apoptotic cells (i.e., annexin-V positive/PI negative; 19.4%), late apoptotic cells (i.e., annexin-V positive/PI positive; 6.3%) and dead cells (i.e., annexin-V negative/PI positive; 1.1%) when cells were co-treated with ISO and TRAIL, compared to cells treated with either ISO or TRAIL. In addition, marked increases of cleaved cas-3, cleaved poly (adenosine diphosphate-ribose) polymerase and DR5 were observed in HEK 293 cells co-treated with ISO and TRAIL. Conclusion: Treatments combining ISO with TRAIL may be responsible for death of HEK 293 cells through DR5 up-regulation. Activation of adrenergic receptors is responsible for the synergistic cell death observed with TRAIL.
엄영우,이재혁,조유환,이중희,김유진,권혁술 대한응급의학회 2018 大韓應急醫學會誌 Vol.29 No.5
Objective: The time to positivity (TTP) of blood culture reflects bacterial load and has been reported to be associated with outcome in bloodstream infections. This study was performed to evaluate the relationship between the TTP of blood culture and the mortality rates associated with sepsis and septic shock according to the site of infection. Methods: We performed a retrospective cohort study on patients with sepsis and septic shock. The rates of blood culture positivity and mortality as well as the relationship between the TTP and 28-day mortality rate were compared among patients with different sites of infection, such as the lungs, abdomen, urogenital tract, and other sites. Results: A total of 2,668 patients were included, and the overall mortality rate was 21.6%. The rates of blood culture positivity and mortality were different among the different infection sites. There was no relationship between the TTP and mortality rates of total, lung, and urogenital infections. Patients with abdominal infections showed a negative correlation between the TTP and 28-day mortality rate. In patients with abdominal infections, a TTP<20 hours was independently associated with 28- day mortality compared with patients with negative blood culture (hazard ratio, 1.73; 95% confidence interval, 1.16-2.58). However, there was no difference in mortality rates of patients with a TTP≥20 hours and a negative blood culture. Conclusion: The shorter TTP in patients with abdominal infections in sepsis and septic shock was associated with a higher 28-day mortality rate.
Mesenchymal stem cell therapy for liver fibrosis
엄영우,심광용,백순구 대한내과학회 2015 The Korean Journal of Internal Medicine Vol.30 No.5
Currently, the most effective treatment for end-stage liver fibrosis is liver transplantation; however, transplantation is limited by a shortage of donor organs, surgical complications, immunological rejection, and high medical costs. Recently, mesenchymal stem cell (MSC) therapy has been suggested as an effective alternate approach for the treatment of hepatic diseases. MSCs have the potential to differentiate into hepatocytes, and therapeutic value exists in their immune-modulatory properties and secretion of trophic factors, such as growth factors and cytokines. In addition, MSCs can suppress inflammatory responses, reduce hepatocyte apoptosis, increase hepatocyte regeneration, regress liver fibrosis and enhance liver functionality. Despite these advantages, issues remain; MSCs also have fibrogenic potential and the capacity to promote tumor cell growth and oncogenicity. This paper summarizes the properties of MSCs for regenerative medicine and their therapeutic mechanisms and clinical application in the treatment of liver fibrosis. We also present several outstanding risks, including their fibrogenic potential and their capacity to promote pre-existing tumor cell growth and oncogenicity.
Adult Stem Cell Therapy in Chronic Liver Diseases
백순구,엄영우 한양대학교 의과대학 2015 Hanyang Medical Reviews Vol.35 No.4
The transplantation of mesenchymal stem cells (MSCs) represents a potentially effective therapy for chronic liver diseases. The potential of MSCs in the treatment of chronic liver disease is based on their ability to differentiate into multiple cell types including hepatocytes, their immunosuppressive properties, and their ability to secrete various trophic factors. This potential has been investigated in clinical and pre-clinical studies. Although the therapeutic mechanisms of MSC transplantation are still not fully characterized, accumulating evidence has revealed that various trophic factors secreted by MSCs play key therapeutic roles in regeneration. These trophic factors not only reduce inflammation, apoptosis, and fibrosis in damaged tissues but also stimulate angiogenesis and tissue regeneration in the impaired liver. In this review, we summarize the basic and therapeutic properties of MSCs, their therapeutic mechanisms of action, and potential transplantation routes for the treatment of chronic liver disease. We also discuss several risks associated with the use of MSCs in therapy, such as their fibrogenic potential and capacity to promote pre-existing tumor cell growth.