ABSTRACT
Objectives@#. Using tissue-engineered materials for esophageal reconstruction is a technically challenging task in animals that requires bioreactor training to enhance cellular reactivity. There have been many attempts at esophageal tissue engineering, but the success rate has been limited due to difficulty in initial epithelialization in the special environment of peristalsis. The purpose of this study was to evaluate the potential of an artificial esophagus that can enhance the regeneration of esophageal mucosa and muscle through the optimal combination of a double-layered polymeric scaffold and a custom-designed mesenchymal stem cell-based bioreactor system in a canine model. @*Methods@#. We fabricated a novel double-layered scaffold as a tissue-engineered esophagus using an electrospinning technique. Prior to transplantation, human-derived mesenchymal stem cells were seeded into the lumen of the scaffold, and bioreactor cultivation was performed to enhance cellular reactivity. After 3 days of cultivation using the bioreactor system, tissue-engineered artificial esophagus was transplanted into a partial esophageal defect (5×3 cm-long resection) in a canine model. @*Results@#. Scanning electron microscopy (SEM) showed that the electrospun fibers in a tubular scaffold were randomly and circumferentially located toward the inner and outer surfaces. Complete recovery of the esophageal mucosa was confirmed by endoscopic analysis and SEM. Esophagogastroduodenoscopy and computed tomography also showed that there were no signs of leakage or stricture and that there was a normal lumen with complete epithelialization. Significant regeneration of the mucosal layer was observed by keratin-5 immunostaining. Alpha-smooth muscle actin immunostaining showed significantly greater esophageal muscle regeneration at 12 months than at 6 months. @*Conclusion@#. Custom-designed bioreactor cultured electrospun polyurethane scaffolds can be a promising approach for esophageal tissue engineering.
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Background@#Extracellular vesicles (EVs) derived from plants have emerged as potential candidates for cosmetic and therapeutic applications. In this study, we isolated EVs from Aloe vera peels (A-EVs) and investigated the antioxidant and wound healing potential of A-EVs. @*Methods@#A-EVs were isolated by ultracentrifugation and tangential flow filtration and were characterized using transmission electron microscopy, nanoparticle tracking analysis. The cytotoxicity and cellular uptake of A-EVs were investigated by WST-1 assay and flow cytometry. The antioxidant effect of A-EVs was evaluated by superoxide dismutase (SOD) activity assay and cellular antioxidant activity (CAA) assay. The wound healing potential was assessed by in vitro scratch assay using human keratinocytes (HaCaT) and fibroblasts (HDF). The expression of nuclear factor erythroid 2–related factor 2 (Nrf2) and their associated genes was analyzed by quantitative RT-PCR. @*Results@#A-EVs displayed a round shape and had diameters from 50 to 200 nm. A-EVs showed good cytocompatibility on human skin cells and were internalized into HaCaT cells via clathrin-, caveolae-mediated endocytosis, and membrane fusion. The SOD activity and CAA assays exhibited that A-EVs had antioxidant activity and reduced intracellular ROS levels in H2O2-treated HaCaT cells in a dose-dependent manner. A scratch assay showed that A-EVs enhanced the migration ability of HaCaT and HDF. Moreover, A-EVs significantly upregulated the mRNA expression of Nrf2, HO-1, CAT, and SOD genes in H2O2-treated HaCaT cells. Our findings reveal that A-EVs could activate the antioxidant defense mechanisms and wound healing process via the Nrf2 activation. @*Conclusion@#Overall results suggest that the A-EVs are promising as a potential agent for skin regeneration.
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BACKGROUND@#Long segmental tracheal repair is challenging in regenerative medicine due to low adhesion of stem cells to tracheal scaffolds. Optimal transplantation of stem cells for tracheal defects has not been established. We evaluated the role of hyaluronic acid (HA) coating of tracheal scaffolds in mesenchymal stem cell (MSC) adhesion and tracheal regeneration in a rabbit model. @*METHODS@#A three-dimensionally printed tubular tracheal prosthesis was incubated with dopa-HA-fluorescein isothiocyanate in phosphate-buffered saline for 2 days. MSCs were incubated with an HA-coated scaffold, and their adhesion was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. HA coated scaffolds with or without MSC seeding were transplanted at the circumferential tracheal defect in rabbits, and survival, rigid bronchoscopy, radiologic findings, and histologic findings were compared between the two groups. @*RESULTS@#HA-coated scaffolds showed better MSC adhesion than non-coated scaffolds. The HA-coated scaffolds with MSC group showed a wider airway and greater mucosal regeneration compared to the HA-coated scaffolds without MSC group. @*CONCLUSION@#HA coating of scaffolds can promote MSC adhesion and tracheal regeneration.
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Objectives@#. A polydioxanone (PDO) stent was developed to treat tracheomalacia in pediatric patients. However, its safety and efficacy need to be verified in animal studies before clinical trials in patients can be conducted. This study evaluated the safety and efficacy of a PDO stent in normal and tracheomalacia-model rabbits. @*Methods@#. In total, 29 New Zealand white rabbits were used: 13 for evaluating the biocompatibility of the PDO stent in normal rabbits and 16 for the creation of a tracheomalacia model. The tracheomalacia model was successfully established in 12 rabbits, and PDO stents were placed in eight of those rabbits. @*Results@#. The PDO stent was successfully positioned in the trachea of the normal rabbits using an endoscopic approach, and its degradation was observed 10 weeks later. The stent fragments did not induce distal airway obstruction or damage, and the mucosal changes that occurred after stent placement were reversed after degradation. The same procedure was performed on the tracheomalacia-model rabbits. The survival duration of the tracheomalacia rabbits with and without stents was 49.0±6.8 and 1.0±0.8 days, respectively. Thus, the PDO stent yielded a significant survival gain (P=0.001). In the tracheomalacia rabbits, stent degradation and granulation tissue were observed 7 weeks after placement, leading to airway collapse and death. @*Conclusion@#. We successfully developed a PDO stent and an endoscopic guide placement system. The degradation time of the stent was around 10 weeks in normal rabbits, and its degradation was accelerated in the tracheomalacia model. The mucosal changes associated with PDO stent placement were reversible. Placement of the PDO stent prolonged survival in tracheomalacia-model rabbits.
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Background@#Extracellular vesicles (EVs) derived from plants have emerged as potential candidates for cosmetic and therapeutic applications. In this study, we isolated EVs from Aloe vera peels (A-EVs) and investigated the antioxidant and wound healing potential of A-EVs. @*Methods@#A-EVs were isolated by ultracentrifugation and tangential flow filtration and were characterized using transmission electron microscopy, nanoparticle tracking analysis. The cytotoxicity and cellular uptake of A-EVs were investigated by WST-1 assay and flow cytometry. The antioxidant effect of A-EVs was evaluated by superoxide dismutase (SOD) activity assay and cellular antioxidant activity (CAA) assay. The wound healing potential was assessed by in vitro scratch assay using human keratinocytes (HaCaT) and fibroblasts (HDF). The expression of nuclear factor erythroid 2–related factor 2 (Nrf2) and their associated genes was analyzed by quantitative RT-PCR. @*Results@#A-EVs displayed a round shape and had diameters from 50 to 200 nm. A-EVs showed good cytocompatibility on human skin cells and were internalized into HaCaT cells via clathrin-, caveolae-mediated endocytosis, and membrane fusion. The SOD activity and CAA assays exhibited that A-EVs had antioxidant activity and reduced intracellular ROS levels in H2O2-treated HaCaT cells in a dose-dependent manner. A scratch assay showed that A-EVs enhanced the migration ability of HaCaT and HDF. Moreover, A-EVs significantly upregulated the mRNA expression of Nrf2, HO-1, CAT, and SOD genes in H2O2-treated HaCaT cells. Our findings reveal that A-EVs could activate the antioxidant defense mechanisms and wound healing process via the Nrf2 activation. @*Conclusion@#Overall results suggest that the A-EVs are promising as a potential agent for skin regeneration.
ABSTRACT
BACKGROUND@#Long segmental tracheal repair is challenging in regenerative medicine due to low adhesion of stem cells to tracheal scaffolds. Optimal transplantation of stem cells for tracheal defects has not been established. We evaluated the role of hyaluronic acid (HA) coating of tracheal scaffolds in mesenchymal stem cell (MSC) adhesion and tracheal regeneration in a rabbit model. @*METHODS@#A three-dimensionally printed tubular tracheal prosthesis was incubated with dopa-HA-fluorescein isothiocyanate in phosphate-buffered saline for 2 days. MSCs were incubated with an HA-coated scaffold, and their adhesion was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. HA coated scaffolds with or without MSC seeding were transplanted at the circumferential tracheal defect in rabbits, and survival, rigid bronchoscopy, radiologic findings, and histologic findings were compared between the two groups. @*RESULTS@#HA-coated scaffolds showed better MSC adhesion than non-coated scaffolds. The HA-coated scaffolds with MSC group showed a wider airway and greater mucosal regeneration compared to the HA-coated scaffolds without MSC group. @*CONCLUSION@#HA coating of scaffolds can promote MSC adhesion and tracheal regeneration.
ABSTRACT
Objectives@#. A polydioxanone (PDO) stent was developed to treat tracheomalacia in pediatric patients. However, its safety and efficacy need to be verified in animal studies before clinical trials in patients can be conducted. This study evaluated the safety and efficacy of a PDO stent in normal and tracheomalacia-model rabbits. @*Methods@#. In total, 29 New Zealand white rabbits were used: 13 for evaluating the biocompatibility of the PDO stent in normal rabbits and 16 for the creation of a tracheomalacia model. The tracheomalacia model was successfully established in 12 rabbits, and PDO stents were placed in eight of those rabbits. @*Results@#. The PDO stent was successfully positioned in the trachea of the normal rabbits using an endoscopic approach, and its degradation was observed 10 weeks later. The stent fragments did not induce distal airway obstruction or damage, and the mucosal changes that occurred after stent placement were reversed after degradation. The same procedure was performed on the tracheomalacia-model rabbits. The survival duration of the tracheomalacia rabbits with and without stents was 49.0±6.8 and 1.0±0.8 days, respectively. Thus, the PDO stent yielded a significant survival gain (P=0.001). In the tracheomalacia rabbits, stent degradation and granulation tissue were observed 7 weeks after placement, leading to airway collapse and death. @*Conclusion@#. We successfully developed a PDO stent and an endoscopic guide placement system. The degradation time of the stent was around 10 weeks in normal rabbits, and its degradation was accelerated in the tracheomalacia model. The mucosal changes associated with PDO stent placement were reversible. Placement of the PDO stent prolonged survival in tracheomalacia-model rabbits.
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BACKGROUND: This study uses the relevance index to understand the condition of regional medical service use for cardiovascular surgery and to identify the medical service use imbalance between regions. METHODS: This study calculated the relevance index of 16 metropolitan cities and provinces using resident registration address data from the Ministry of Government Administration and Home Affairs and the 2010–2014 health insurance, medical care assistance, and medical benefits claims data from the Health Insurance Review and Assessment Service. We identified developments over the 5-year time period and analyzed the level of regional imbalance regarding cardiovascular surgery through the relative comparison of relevance indexes between cardiovascular and other types of surgery. RESULTS: The relevance index was high in large cities such as Seoul, Daegu, and Gwangju, but low in regions that were geographically far from the capital area, such as the Gangwon and Jeju areas. Relevance indexes also fell as the years passed. Cardiovascular surgery has a relatively low relevance index compared to key types of surgery of other fields, such as neurosurgery and colorectal surgery. CONCLUSION: This study identified medical service use imbalance between regions for cardiovascular surgery. Results of this study demonstrate the need for political intervention to enhance the accessibility of necessary special treatment, such as cardiovascular surgery.
Subject(s)
Colorectal Surgery , Insurance, Health , Neurosurgery , SeoulABSTRACT
BACKGROUND: This study analyzed the association between the volume of heart surgeries and treatment outcomes for hospitals in the last five years. METHODS: Hospitals that perform heart surgeries were chosen throughout Korea as subjects using from the Health Insurance Review and Assessment Service. The treatment outcome of the heart surgeries was defined as the mortality within 30 postoperative days, while the annual volume of the surgeries was categorized. Logistic regression was used as the statistical analysis method, and the impacts of the variables on the heart surgery treatment outcomes were then analyzed. RESULTS: The chance of death of patients who received surgery in a hospital that performed 50 or more surgeries annually was noticeably lower than patients receiving operations from hospitals that performed fewer than 50 surgeries annually, indicating that the chance of death decreases as the annual volume of heart surgeries in the hospital increases. In particular, the mortality rate in hospitals that performed more than 200 surgeries annually was less than half of that in hospitals that performed 49 or fewer surgeries annually. CONCLUSION: These results indicate that accumulation of a certain level of heart surgery experience is critical in improving or maintaining the quality of heart surgeries. In order to improve the treatment outcomes of small hospitals, a support policy must be implemented that allows for cooperation with experienced professionals.
Subject(s)
Humans , Heart , Insurance, Health , Korea , Logistic Models , Methods , Mortality , Quality of Health Care , Thoracic Surgery , Treatment OutcomeABSTRACT
BACKGROUND: This study aimed to develop the models for regional cardiac surgery centers, which take regional characteristics into consideration, as a policy measure that could alleviate the concentration of cardiac surgery in the metropolitan area and enhance the accessibility for patients who reside in the regions. METHODS: To develop the models and set standards for the necessary personnel and facilities for the initial management plan, we held workshops, debates, and conference meetings with various experts. RESULTS: After partitioning the plan into two parts (the operational autonomy and the functional comprehensiveness), three models were developed: the ‘independent regional cardiac surgery center’ model, the ‘satellite cardiac surgery center within hospitals’ model, and the ‘extended cardiac surgery department within hospitals’ model. Proposals on personnel and facility management for each of the models were also presented. A regional cardiac surgery center model that could be applied to each treatment area was proposed, which was developed based on the anticipated demand for cardiac surgery. The independent model or the satellite model was proposed for Chungcheong, Jeolla, North Gyeongsang, and South Gyeongsang area, where more than 500 cardiac surgeries are performed annually. The extended model was proposed as most effective for the Gangwon and Jeju area, where more than 200 cardiac surgeries are performed annually. CONCLUSION: The operation of regional cardiac surgery centers with high caliber professionals and quality resources such as optimal equipment and facility size, should enhance regional healthcare accessibility and the quality of cardiac surgery in South Korea.
Subject(s)
Humans , Delivery of Health Care , Education , Health Facilities , Health Services Accessibility , Korea , Quality of Health Care , Thoracic SurgeryABSTRACT
BACKGROUND: While demand for cardiovascular surgery is expected to increase gradually along with the rapid increase in cardiovascular diseases with respect to the aging population, the supply of thoracic and cardiovascular surgeons has been continuously decreasing over the past 10 years. Consequently, this study aims to achieve guidance in establishing health care policy by analyzing the supply and demand for cardiovascular surgeries in the medical service area of Korea. METHODS: After investigating the actual number of cardiovascular surgeries performed using the National Health Insurance claim data of the Health Insurance Review and Assessment Service, as well as drawing from national statistics concerning the elderly population aged 65 and over, this study estimated the number of future cardiovascular surgeries by using a cell-based model. To be able to analyze the supply and demand of surgeons, the recent status of new surgeons specializing in thoracic and cardiovascular surgeries and the ratio of their subspecialties in cardiovascular surgeries were investigated. Then, while taking three different scenarios into account, the number of cardiovascular surgeons expected be working in 5-year periods was projected. RESULTS: The number of cardiovascular surgeries, which was recorded at 10,581 cases in 2014, is predicted to increase consistently to reach a demand of 15,501 cases in 2040—an increase of 46.5%. There was a total of 245 cardiovascular surgeons at work in 2014. Looking at 5 year spans in the future, the number of surgeons expected to be supplied in 2040 is 184, to retire is 249, and expected to be working is 309—an increase of −24.9%, 1.6%, and 26.1%, respectively compared to those in 2014. This forecasts a demand-supply imbalance in every scenario. CONCLUSION: Cardiovascular surgeons are the most central resource in the medical service of highly specialized cardiovascular surgeries, and fostering the surgeons requires much time, effort, and resources; therefore, by analyzing the various factors affecting the supply of cardiovascular surgeons, an active intervention of policies can be prescribed for the areas that have failed to meet the appropriate market distributions.
Subject(s)
Aged , Humans , Aging , Cardiovascular Diseases , Delivery of Health Care , Economics, Medical , Foster Home Care , Health Policy , Health Services Needs and Demand , Insurance, Health , Korea , National Health Programs , Surgeons , Thoracic SurgeryABSTRACT
The authors analyze the citation of Journal of Korean Neurosurgical Society, based on Korean Medical Citation Index(KoMCI) from 2000 to 2003. The impact factor of Journal of Korean Neurosurgical Society(JKNS) was 0.079 at 2000, and the score was below average among 69 KoMCI articles. The impact factor remained about the same value at 2001, 2002. However, it rised to 0.176 at 2003. This increase in citation was mostly by self-citation. Although the impact factor showed some improvement, yet it needs more time to conclude that the status of JKNS is in steady state of improvement. In order to make JKNS as a journal with high reputation and authority, the effort of every members of Korean Neurosurgical Society is essential.
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The authors present an analysis of papers published on Journal of Korean Neurosurgical Society(JKNS) in 2004. There were 217 peer reviewed articles. 118 were clinical articles, 78 were case reports, 17 were laboratory investigations, two were technical reports, and the other two were special articles. This distribution was not statistically different from 2003(p=0.53). Number of English articles was increased with statistical significance (p<0.001). There were 46 English clinical articles, 72 English case reports, nine English laboratory investigations, and so on. The trends in papers on JKNS in 2004 are thought to be desirable ones for JKNS to become an internationally evaluated journal.
Subject(s)
Peer ReviewABSTRACT
The authors present an analysis of papers published on Journal of Korean Neurosurgical Society in 2003. Total 236 articles were published and the contents were 114 clinical articles(48.3%), 18 laboratory investigations(7.6%), 99 case reports(42.0%), and five technical notes(2.1%), respectively. Additionally, two review articles and two special articles were published on request from the editorial board. We analyzed the changes in trend of papers from the year 2002.
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The authors analyze the citation of Journal of Korean Neurosurgical Society, which is based on Korean Medical Citation Index(KoMCI)2000. The average number of Korean references were 1.2, and that of Journal of Korean Neurosurgical Society was 1.0. It shared only 3.9% of all references. The impact factor of Journal of Korean Neurosurgical Society was 0.079, and the score was below average among 69 KoMCI articles. In order to improve the status of Journal of Korean Neurosurgical Society, the effort of every members of Korean Neurosurgical Society is essential.
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The authors present an analysis of publications on Journal of Korean Neurosurgical Society in 2002. Total 219 articles were published and the contents were clinical articles 94(42.9%), laboratory investi-gations 22(10.0%), case reports 102(46.6%), and review article one(0.5%), respectively. We hope that this analysis might be one of the stimuli to improve Journal of Korean Neurosurgical Society.