Publications by authors named "Ho-Young Song"

248 Publications

Acetazolamide-eluting biodegradable tubular stent prevents pancreaticojejunal anastomotic leakage.

J Control Release 2021 Jul 10;335:650-659. Epub 2021 Jun 10.

Biomedical Engineering Research Center, Asan Institute for Life Sciences, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea; Division of Hepatobiliary Pancreas Surgery, Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea; Asan Medical Institute of Convergence Science and Technology (AMIST), Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea. Electronic address:

Postoperative pancreatic fistula at the early stage can lead to auto-digestion, which may delay the recovery of the pancreaticojejunal (PJ) anastomosis. The efficacy and safety of an acetazolamide-eluting biodegradable tubular stent (AZ-BTS) for the prevention of self-digestion and intra-abdominal inflammatory diseases caused by pancreatic juice leakage after PJ anastomosis in a porcine model were investigated. The AZ-BTS was successfully fabricated using a multiple dip-coating process. Then, the drug amount and release profile were analyzed. The therapeutic effects of AZ were examined in vitro using two kinds of pancreatic cancer cell lines, AsPC-1 and PANC-1. The efficacy of AZ-BTS was assessed in a porcine PJ leakage model, with animals were each assigned to a leakage group, a BTS group and an AZ-BTS group. The overall mortality rates in these three groups were 44.4%, 16.6%, and 0%, respectively. Mean α-amylase concentrations were significantly higher in the leakage and BTS groups than in the AZ-BTS group on day 2-5 (p < 0.05 each all). The luminal diameters and areas of the pancreatic duct were significantly larger in the leakage group than in the BTS and AZ-BTS groups (p < 0.05 each all). These findings indicate that AZ-BTS can significantly suppress intra-abdominal inflammatory diseases caused by pancreatic juice leakage and also prevent late stricture formation at the PJ anastomotic site in a porcine model.
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http://dx.doi.org/10.1016/j.jconrel.2021.06.010DOI Listing
July 2021

Efficacy and tolerability of metallic stent in patients with malignant prostatic obstruction secondary to prostatic cancer.

Low Urin Tract Symptoms 2021 Jul 25;13(3):329-334. Epub 2021 Mar 25.

Department of Urology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Objective: To evaluate the efficacy and tolerability of a self-expandable covered metallic stent in patients with malignant prostatic obstruction secondary to prostate cancer (PC).

Methods: We reviewed 22 cases of insertion of self-expandable covered metallic stents with barbs. Data were collected about PC status. Uroflowmetry variables, residual urine volume, International Prostate Symptom Score (IPSS), quality of life (QOL), and duration from stent insertion to removal were surveyed. These clinical parameters were compared before and after stent insertion.

Results: The patients with PC showed a mean age of 75.5 ± 6.5 years and mean 5.1 ± 1.9 Charlson comorbidity index. The average flow rate (2.4 ± 1.9 vs 5.9 ± 2.4 mL/s, P = .005), peak flow rate (6.9 ± 6.2 vs 14.1 ± 5.5 mL/s, P = .003), flow time (54.6 ± 29.1 vs 23.6 ± 13.7 s, P = .002), residual urine volume (178.7 ± 195.5 vs 7.0 ± 7.1 mL, P = .004), IPSS (26.2 ± 8.1 vs 8.0 ± 6.5 points, P = .001), and QOL (4.7 ± 1.3 vs 2.4 ± 2.1 points, P = .030) improved between before and after stent insertion, respectively. Pain was the most common complication, but 60% of the patients were managed without any intervention. There were hematuria, urinary retention, urinary frequency, obstruction, and urinary incontinence. However, there was no urinary tract infection due to the stent. The median time to stent removal was 5.7 months.

Conclusions: The stent was maintained for about 6 months with improved objective and subjective outcomes. The patients with PC, who had a poor comorbidity index and advanced PC status showed a tolerable maintenance period. Self-expandable covered metallic stents can be used for PC patients with a short life expectancy and unsuitability for general anesthesia.
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http://dx.doi.org/10.1111/luts.12367DOI Listing
July 2021

Creation of an ex-vivo bovine kidney flow model for testing embolic agents: work in progress.

CVIR Endovasc 2021 Feb 3;4(1):20. Epub 2021 Feb 3.

Long School of Medicine, University of Texas Health Science Center, 7703 Floyd Curl Drive San Antonio, San Antonio, TX, 78229, USA.

Objectives: To develop an ex- vivo perfusion flow model using a bovine kidney for future testing of embolic agents in an inexpensive and easy way.

Methods: Six bovine adult kidneys were used for this study. Kidneys were cannulated and perfused via a roller pump. Three embolic agents, coils, Gelfoam, and a glue mixture of Histoacryl + Lipiodol, were deployed by targeting three secondary segmental arteries per kidney via a 5Fr catheter under fluoroscopic guidance. Cannulation time, success rate of segmental artery selection and embolic agent deployment, total operational time, and fluoroscopy dose were recorded.

Results: Average kidney weight was 0.752 +/- 0.094 kg. All six bovine kidneys were successfully cannulated in 21.6 min +/- 3.0 min. Deployment of coils and glue was achieved in every case (12/12); however, Gelfoam injection was not successful in one instance (5/6, 83%). Coil deployment demonstrated no embolic effect while Gelfoam and glue injections demonstrated decreased distal contrast filling post-embolization. Mean dose area product was 12.9 ± 1.8 Gy·cm2, fluoroscopy time was 10 ± 4 min and operational time was 27 ± 8 min.

Conclusions: We describe the creation of an ex vivo bovine kidney flow model for the preclinical evaluation of different embolic materials. The flow model can be modified to provide extensive bench testing and it is a promising tool for hands -on training in basic and advanced embolization techniques .
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http://dx.doi.org/10.1186/s42155-021-00210-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7859154PMC
February 2021

Local Heat Treatment for Suppressing Gastroduodenal Stent-Induced Tissue Hyperplasia Using Nanofunctionalized Self-Expandable Metallic Stent in Rat Gastric Outlet Model.

ACS Biomater Sci Eng 2020 04 19;6(4):2450-2458. Epub 2020 Mar 19.

Departments of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea.

Despite the promising results from the placement of covered or uncovered self-expandable metallic stent (SEMS) as a nonsurgical therapeutic option for the malignant gastric outlet obstruction (GOO), the long patency of the stent is still limited because of stent-induced tissue hyperplasia. Here, a local heat treatment using a nanofunctionalized SEMS is proposed for suppressing stent-induced tissue hyperplasia during GOO treatment. Highly efficient photothermal gold nanoparticle (GNP) transducer-coated SEMSs (GNP-SEMSs) were prepared for local heat treatment in rat gastric outlet. The in vivo heating temperature in rat gastric outlet model was evaluated and compared with in vitro heating temperature. Three groups of our developed 45 rat gastric outlet models were used: group A, noncoated SEMS only; group B, GNP-SEMS plus local heating; and group C, GNP-SEMS only to investigate in vivo efficacy of GNP-SEMS mediated local heating. Ten rats per group were sacrificed for 4 weeks, and five rats per group were sacrificed immediately after local heat treatment. The in vivo heating temperature was found to be 10.8% lower than the in vitro heating temperatures. GNP-SEMSs were successfully placed through a percutaneous approach into the rat gastric outlet ( = 45). The therapeutic effects of GNP-SEMS were assessed by histologic examination including hematoxylin-eosin, Masson trichrome, immunohistochemistry (TUNEL and CD31), and immunofluorescence (Ki67), and the results showed significant prevention of tissue hyperplasia following stent placement without adjacent gastrointestinal tissue damage. GNP-SEMS-mediated local heating could be an alternative therapeutic option for the suppression of tissue hyperplasia following stent placement in benign and malignant GOOs.
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http://dx.doi.org/10.1021/acsbiomaterials.0c00307DOI Listing
April 2020

The Establishment of a Fast and Safe Orthotopic Colon Cancer Model Using a Tissue Adhesive Technique.

Cancer Res Treat 2021 Jul 15;53(3):733-743. Epub 2020 Dec 15.

Department of Biomedical Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Purpose: We aimed to develop a novel method for orthotopic colon cancer model, using tissue adhesive in place of conventional surgical method.

Materials And Methods: RFP HCT 116 cell line were used to establish the colon cancer model. Fresh tumor tissue harvested from a subcutaneous injection was grafted into twenty nude mice, divided into group A (suture method) and group B (tissue adhesive method). For the group A, we fixed the tissue on the serosa layer of proximal colon by 8-0 surgical suture. For the group B, tissue adhesive (10 μL) was used to fix the tumor. The mortality, tumor implantation success, tumor metastasis, primary tumor size, and operation time were compared between the two groups. Dissected tumor tissue was analyzed for the histology and immunohistochemistry. Also, we performed tumor marker analysis.

Results: We observed 30% increase in graft success and 20% decrease in mortality, by using tissue adhesive method, respectively. The median colon tumor size was significantly increased by 4 mm and operation time was shortened by 6.5 minutes. The H&E showed similar tumor structure between the two groups. The immunohistochemistry staining for cancer antigen 19-9, carcinoembryonic antigen, cytokeratin 20, and Ki-67 showed comparable intensities in both groups. Real-time quantitative reverse transcription analysis showed eight out of nine tumor markers are unchanged in the tissue adhesive group. Western blot indicated the tissue adhesive group expressed less p-JNK (apototic marker) and more p-MEK/p-p38 (proliferation marker) levels.

Conclusion: We concluded the tissue adhesive method is a quick and safe way to generate orthotopic, colon cancer model.
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http://dx.doi.org/10.4143/crt.2020.494DOI Listing
July 2021

cIRCR201-dPBD, a Novel Pyrrolobenzodiazepine Dimer-Containing Site-Specific Antibody-Drug Conjugate Targeting c-Met Overexpression Tumors.

ACS Omega 2020 Oct 29;5(40):25798-25809. Epub 2020 Sep 29.

Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul 06355, Republic of Korea.

c-Met, as a receptor expressed on the cell membrane, contributes to the growth and metastasis of tumors, as well as angiogenesis, mainly through the hepatocyte growth factor (HGF)/c-Met axis during tumor progression. Although several c-Met inhibitors, including small molecules and monoclonal antibody inhibitors, are currently being investigated, their clinical outcomes have not been promising. Development of an antibody-drug conjugate (ADC) against c-Met could be an attractive therapeutic strategy that would provide superior antitumor efficacy with broad-spectrum c-Met expression levels. In the present study, site-specific drug-conjugate technology was applied to develop an ADC using the human-mouse cross-reactive c-Met antibody and a prodrug pyrrolobenzodiazepine (PBD). The toxin payload was uniformly conjugated to the light-chain C-terminus of the native cIRCR201 antibody (drug-to-antibody ratio = 2), as confirmed using LC-MS. Using a high-throughput screening system, we found that cIRCR201-dPBD exhibited varying sensitivities depending on the expression levels of c-Met, and it induced receptor-mediated endocytosis and toxin-mediated apoptosis in 47 different cancer cell lines. cIRCR201-dPBD also showed significant antitumor activity on the -amplified cancer cells using in vivo xenograft models. Therefore, cIRCR201-dPBD could be a promising therapeutic strategy for tumors with c-Met expression.
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http://dx.doi.org/10.1021/acsomega.0c03102DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7557224PMC
October 2020

A Novel Intragastric Satiety-Inducing Device to Inhibit Weight Gain in Juvenile Pigs: a Pilot Study.

Obes Surg 2020 11 4;30(11):4643-4651. Epub 2020 Sep 4.

Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea.

Background And Aims: Minimally invasive therapies for obesity are a bridge between lifestyle interventions and bariatric surgery. We developed a novel device to reduce weight gain rate and evaluated its safety and efficacy in juvenile pigs.

Methods: The intragastric satiety-inducing device (ISD) comprises a self-expandable esophageal metal stent connected to a star-shaped disc placed in the stomach fundus. Eight juvenile pigs were randomized into ISD (n = 5) and control (n = 3) groups. Body weight and serum ghrelin hormone were monitored weekly for 6 weeks. One pig was followed up for 4 additional weeks (rebound pig) after ISD removal. Histological examination and immunohistochemistry for the interstitial cells of Cajal (ICCs) were performed.

Results: ISD placement was successful in all pigs. Two ISDs (40%) migrated at 4 and 5 weeks after placement. Weight gain rates were significantly lower in the ISD group than in the control group from week 1 to 6 but were higher in the rebound pig than in a control pig from week 7 to 10. Mean ghrelin hormone level was higher in the control group than in the ISD group from week 1 to 6. ISD induced reversible inflammatory changes in the esophagus and stomach fundus. The number of ICCs was lesser in ISD pigs than in control and rebound pigs.

Conclusions: ISD placement is feasible and safe in juvenile pigs. It decreases weight gain rate but induces reversible inflammatory reaction and tissue hyperplasia. Its mechanism may be related to pressure exertion on the stomach fundus or gastric motility alteration.
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http://dx.doi.org/10.1007/s11695-020-04930-5DOI Listing
November 2020

Metallic Stent Mesh Coated with Silver Nanoparticles Suppresses Stent-Induced Tissue Hyperplasia and Biliary Sludge in the Rabbit Extrahepatic Bile Duct.

Pharmaceutics 2020 Jun 17;12(6). Epub 2020 Jun 17.

Biomedical Engineering Research Center, Asan Institute for Life Sciences, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea.

Recent therapeutic strategies to suppress restenosis after biliary stent placement are insufficient. Here, we demonstrate the usefulness of a self-expandable metal stent (SEMS), a stent mesh coated with silver nanoparticles (AgNPs), for suppression of both stent-induced tissue hyperplasia and biliary sludge formation in the rabbit bile duct. The AgNP-coated SEMSs were prepared using a simple bio-inspired surface modification process. Then, the prepared SEMSs were successfully placed in 22 of 24 rabbits. Sludge formation in the AgNP-coated SEMS groups was significantly decreased compared to the control group on gross findings. Cholangiographic and histologic examinations demonstrated significantly decreased tissue hyperplasia in the AgNP-coated SEMS groups compared with the control group ( < 0.05 for all). There were no differences between the AgNP-coated SEMS groups ( > 0.05 for all). However, in the group coated with the greatest concentration of AgNPs (Group D), submucosal fibrosis was thicker than in the other AgNP-coated groups ( < 0.05 for all). The AgNP-coated metallic stent mesh significantly suppressed stent-induced tissue hyperplasia and biliary sludge formation in the rabbit bile duct. Taken together, the AgNP coating strategy developed in this study could be widely utilized in non-vascular medical devices for anti-bacterial and anti-inflammatory responses.
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http://dx.doi.org/10.3390/pharmaceutics12060563DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7356520PMC
June 2020

EW-7197, a Transforming Growth Factor-Beta Type I Receptor Kinase Inhibitor, Ameliorates Acquired Lymphedema in a Mouse Tail Model.

Lymphat Res Biol 2020 10 27;18(5):433-438. Epub 2020 Feb 27.

Department of Biomedical Engineering Research Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.

Acquired lymphedema is a common consequence of cancer surgery. Fibrosis is one of the main causes of chronic lymphedema since it hinders lymphatic regeneration and this causes a significant decrease in lymphatic flow and accumulation of excessive protein-rich fluid. The transforming growth factor-β1 (TGF-β1) signaling pathway is known in a process of wound repair and fibrosis. In our study, the purpose was to evaluate the efficacy of EW-7197, a peroral TGF-β type I receptor kinase inhibitor, in treating acquired lymphedema. For lymphedema mouse tail model, we used 10- to 12-week-old female C57BL/6 mice. The skin was circumferentially excised, making a circular band followed by cauterization of lymphatic collecting vessels. Two groups were made in this study: control and treatment. The treatment group ( = 12) received a solution consisting of 0.1 mL of artificial gastric juice and 20 mg/kg EW-7197 by gavage once daily. For evaluation, tail diameter measurement, fluorescence lymphography, and immunofluorescence images were used. EW-7197 treatment ameliorates acquired lymphedema in a mouse tail model by increasing lymphangiogenesis and interstitial flow of the lymphatics by inhibition of the fibrosis. The differences in maximal tail thicknesses between the control and treatment groups were statistically significant from 2 to 4 weeks after surgery. The treatment group showed a greater number of lymphatic vessels at the surgery site than the control group. The treatment group also showed more FITC coverage area at the surgery site. EW-7197 treatment ameliorates acquired lymphedema in a mouse tail model by increasing lymphangiogenesis and interstitial flow.
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http://dx.doi.org/10.1089/lrb.2018.0070DOI Listing
October 2020

Intragastric satiety-inducing device reduces food intake and suppresses body weight gain in a rodent model.

Surg Endosc 2021 03 24;35(3):1052-1057. Epub 2020 Feb 24.

Department of Interventional Therapy, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 17 Panjiayuan Nanli, Chaoyang District, Beijing, 100021, China.

Background: An intragastric satiety-inducing device (ISD) (Full Sense Device; Baker, Foote, Kemmeter, Walburn, LLC, Grand Rapids, MI) is a novel weight-loss device, which may induce satiety by applying continuous pressure on the gastric cardia. This study investigated the effect of the ISD on food intake and body weight gain in a rodent model.

Methods: Thirty-two male Sprague-Dawley rats (weight, 250-300 g) were randomly divided into four groups of eight individuals. Single-disk (SD) and double-disk (DD) group animals underwent peroral placement of a single- or double-disk ISD, respectively, under fluoroscopic guidance. The ISD comprised a 4 mm × 1.5 cm nitinol stent placed in the lower esophagus and one (single-disk) or two (double-disk) 2.5-cm-diameter star-shaped nitinol disks placed in the gastric fundus. Esophageal stent (ES) and sham-operated (SO) group animals underwent peroral placement of the ES part of the ISD and a sham operation, respectively.

Results: Food intake was significantly different among the four groups over the 4-week study period (P < 0.001); food intake was significantly lower in the SD and DD groups than in the SO group (P = 0.016 and P = 0.002, respectively) but was not significantly different between the SD and DD groups (P > 0.999) and between the ES and SO groups (P = 0.677). Body weight was significantly different among the four groups by the end of the study period (P < 0.001); body weight was significantly lower in the DD group than in the SD, ES, and SO groups (P = 0.010, P < 0.001, and P < 0.001, respectively) and in the SD group than in the SO group (P = 0.001), but it was not significantly different between the ES and SO groups (P = 0.344).

Conclusion: ISD reduced food intake and suppressed body weight gain in a rodent model.
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http://dx.doi.org/10.1007/s00464-020-07467-xDOI Listing
March 2021

A Novel Biodegradable Tubular Stent Prevents Pancreaticojejunal Anastomotic Stricture.

Sci Rep 2020 01 30;10(1):1518. Epub 2020 Jan 30.

Biomedical Engineering Research Center, Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea.

Stricture of pancreatic-enteric anastomoses is a major late complication of a pancreaticoduodenectomy for the treatment of a periampullary tumor and can lead to exocrine and endocrine insufficiency such as malnutrition and diabetes mellitus. We investigated the safety and efficacy of a biodegradable tubular stent (BTS) for preventing a pancreaticojejunostomy (PJ) anastomotic stricture in both a rat and porcine model. The BTS was manufactured using a terpolymer comprising poly p-dioxanone, trimethylene carbonate, and glycolide. A cohort of 42 rats was randomized into 7 groups of 6 animals each after BTS placement into the duodenum for the biodegradation assay. A total of 12 pigs were randomized equally into a control and BTS placement group. The effectiveness of the BTS was assessed by comparing radiologic images with histologic results. Surgical procedures and/or BTS placements were technically successful in all animals. The median mass losses of the removed BTS samples from the rat duodenum were 2.1, 6.8, 11.2, 19.4, 26.1, and 56.8% at 1, 2, 3, 4, 6, and 8 weeks, respectively. The BTS had completely degraded at 12 weeks in the rats. In the porcine PJ model, the mean luminal diameter and area of the pancreatic duct in the control group was significantly larger than in the BTS group (all p < 0.05). BTS placement thus appears to be safe and effective procedure for the prevention of PJ anastomotic stricture. These devices have the potential to be used as a temporary stent placement to treat pancreatic-enteric anastomoses, but further investigations are required for optimization in human.
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http://dx.doi.org/10.1038/s41598-019-57271-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6992790PMC
January 2020

Clinical effectiveness and safety of self-expanding metal stent placement following palliative chemotherapy in patients with advanced esophageal cancer.

Abdom Radiol (NY) 2020 02;45(2):563-570

Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea.

Purpose: To investigate the effect of prior chemotherapy on self-expanding metal stent (SEMS)-related complications in patients with locally advanced primary esophageal cancer.

Materials And Methods: Data from patients with locally advanced primary esophageal cancer who received SEMS placement with or without prior chemotherapy were retrospectively reviewed. Patients were grouped according to prior palliative therapy: group A (n = 41) had received SEMS only, and group B (n = 64) had received palliative chemotherapy prior to SEMS placement. Patients' age, stricture length, tumor location, and dysphagia score prior to SEMS placement were evaluated. The overall patient cohort had a median follow-up period of 129 days (range 11-463). Outcomes after SEMS placement, including technical and clinical success rates, the occurrence of complications, and overall survival, were compared.

Results: There were no significant differences between the two groups regarding patients' age, stricture length, tumor location, and dysphagia score prior to SEMS placement. SEMS placement was technically successful in all patients, with no procedure-related complications reported. Clinical success was achieved in 95.1% of patients in group A and 96.8% of patients in group B. The duration of stent patency was significantly shorter in group B [162 days; 95% confidence interval (CI) 126.6-198.4 vs. group A (339 days; 95% CI 258.8-419.3], p = 0.001. No significant differences were seen between the two groups regarding dysphagia score improvement [group A (3.15 ± 0.57 to 1.17 ± 0.83; p < 0.001) and group B (3.17 ± 0.80 to 1.14 ± 0.79; p < 0.001); p = 0.66], complications [group A (10/41), and group B (24/64); p = 0.094], or overall survival [the median and mean overall survival periods were 105 (95% CI 30-180) and 132 days (95% CI 97-167), respectively, in group A, and 126 (95% CI 88-164) and 156 days (95% CI 132-180), respectively, in group B; p = 0.592].

Conclusion: Prior chemotherapy did not increase the risk of complications following SEMS placement in patients with locally advanced esophageal cancer. SEMS patency was significantly longer in patients who did not receive chemotherapy prior to SEMS placement.

Level Of Evidence: Level 4, Case Series.
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http://dx.doi.org/10.1007/s00261-019-02245-3DOI Listing
February 2020

Fluoroscopic Balloon Dilation Using a Flexible Guide Wire to Treat Obstructive Eustachian Tube Dysfunction.

J Vasc Interv Radiol 2019 Oct 10;30(10):1562-1566. Epub 2019 Aug 10.

Rehabilitation, Asan Medical Center, University of Ulsan College of Medicine, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea.

Purpose: To prospectively evaluate the midterm outcomes of fluoroscopic eustachian tube (E-tube) balloon dilation by using a flexible guide wire in patients with obstructive E-tube dysfunction.

Materials And Methods: From October 2016 to September 2017, adult outpatients with persistent otitis media who were unable to perform the Valsalva maneuver were prospectively enrolled. The analysis included 32 E-tubes from 31 patients (18 women, 13 men; mean age, 47 years old, range 25-72 years). Participants underwent fluoroscopic E-tube balloon dilation with a 0.035-inch flexible guide wire and a 6- × 20-mm balloon catheter. Clinical examinations to check for the ability to perform the Valsalva maneuver and otomicroscopy were conducted at 1 week and then at 1, 3, 12, and 18 months after the procedure.

Results: Balloon dilation was technically successful in all E-tubes. The mean time required for the procedure was 6.9 minutes (range, 5.8-10.3 minutes). The Valsalva maneuver was successful in opening 25 of 32 E-tubes (78.1%) at 3 months after balloon dilation. During the median follow-up of 15.9 months, failure of the Valsalva maneuver occurred in 4 of 25 improved E-tubes (16%), yielding a 2-year patency rate of 84%.

Conclusions: The fluoroscopic balloon dilation results were encouraging, and using a flexible guide wire for E-tube balloon dilation did not cause a false passage.
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http://dx.doi.org/10.1016/j.jvir.2019.04.041DOI Listing
October 2019

Radiation Inhibits Lymph Drainage in an Acquired Lymphedema Mouse Hindlimb Model.

Lymphat Res Biol 2020 02 24;18(1):16-21. Epub 2019 Jun 24.

Departement of Rehabilitation Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.

Radiation therapy has been applied to prolong the duration of lymphedema. This study aimed to evaluate the effect of radiation on the development of lymphedema in a mouse hindlimb model. A total of 24 Balb/c mice underwent the right popliteal lymph node excision and the afferent and efferent lymphatics blockage. The radiation group ( = 12) received a single 20 Gy radiation 1 day before surgery in the right hindlimb of each mouse, whereas the control group ( = 12) only received surgery without radiation. The right hindpaw thickness of each mouse was measured twice a week for 4 weeks. Fluorescence microscopy images using fluorescein isothiocyanate-dextran tracer were obtained once weekly. Immunohistochemical (IHC) staining images using anti-lymphatic vessel endothelial hyaluronan receptor-1 (anti-LYVE-1) were obtained at 4 weeks after surgery. The radiation group showed significant increase in the thickness of the right hind paws from 0.5 to 2 weeks compared with the control group. As for fluorescence lymphography, the radiation group showed a lower number of regenerated lymphatics and more congestion of tracers in the operated limb at the surgery sites at 1, 2, 3, and 4 weeks after surgery. For the IHC analysis, the radiation group showed a lower number of regenerated lymphatics per high-power field at the surgery site than the control group. Radiation therapy transiently aggravated the extent of lymphedema by inhibiting regenerated lymphatics in a mouse hindlimb model. However, it did not prolong the duration of lymphedema because the cutaneous interstitial flow contributes to the lymphatic fluid clearance.
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http://dx.doi.org/10.1089/lrb.2018.0072DOI Listing
February 2020

Fully covered self-expandable esophageal metallic stents in patients with inoperable malignant disease who survived for more than 6 months after stent placement.

Br J Radiol 2019 Aug 2;92(1100):20190321. Epub 2019 Jul 2.

1 Departments of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea.

Objectives: To investigate the clinical outcomes of fully covered self-expanding metal stent (FCSEMS) placement in patients with malignant esophageal obstruction who survived longer than 6 months.

Methods: From January 2002 to January 2018, 88 FCSEMS were placed in 64 patients (mean age 62.9 ± 11.6 years; 58 males) with inoperable malignant esophageal obstruction with or without esophago-respiratory fistula. Only patients who survived more than 6 months with FCSEMS in place were included. Data regarding technical and clinical success, complications, reinterventions, stent patency, and patient survival were obtained from a prospectively maintained hospital database.

Results: The technical and clinical success rates were 100 % (64/64). During follow-up, the median dysphagia score significantly improved (3.09 ± 0.68 to 1.05 ± 0.60, < 0.001). The complication rate was 48.8 %. Multivariate analysis revealed that only longer stenting duration was associated with complications [hazard ratio = 1.220, 95 % confidence interval (CI) (1.074-2.760), = 0.039]. The median follow-up duration was 257 days (range, 181-969). The median stent patency duration was 289 days [95% CI (209.9-368.1)]. The median survival was 254 days [95% CI (219.7-288.3)].

Conclusions: Our data suggest that esophageal FCSEMS placement is an effective option for patients with malignant dysphagia when survival longer than 6 months is expected. The rate of complications increases with time, and SEMS development is needed to keep up with the advancement in oncological treatment.

Advances In Knowledge: Fully covered esophageal self-expandable stent placement is effective in patients surviving more than 6 months, however, the rate of complications also increases. SEMS development is needed to cope with the advancement in oncological treatment.
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http://dx.doi.org/10.1259/bjr.20190321DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6724637PMC
August 2019

Fluoroscopic self-expandable metallic stent placement for treating post-operative nonanastomotic strictures in the proximal small bowel: a 15-year single institution experience.

Br J Radiol 2019 Jun 30;92(1098):20180957. Epub 2019 Apr 30.

5 Department of Radiologic Technology, Cheju Halla University , Jeju , Republic of Korea.

Objective: To evaluate the efficacy and safety of fluoroscopic self-expandable metallic stent (SEMS) placement for treating postoperative nonanastomotic strictures in the proximal small bowel.

Methods: Data from 8 consecutive patients (mean age, 63.8 ± 6.9 years; 7 males and 1 female) who underwent 17 fluoroscopic SEMS placement procedures in total for treating postoperative nonanastomotic strictures in the proximal jejunum were retrospectively reviewed. The most recent surgery for all the patients was total gastrectomy with esophagojejunostomy. Strictures were located in the proximal jejunum in all patients. The mean length of the strictures was 5.8 ± 2.0 cm. Five patients with comorbidities were poor surgical candidates. Four patients underwent fluoroscopic balloon dilation, three of whom showed no resolution of obstructive symptoms and one demonstrated recurrence of symptoms.

Results: Technical and clinical success was achieved in 100% (17/17) SEMS procedures. Complete resolution of obstructive symptoms and improvement in oral intake status occurred within 3 days after all procedures, rendering a clinical success rate of 100% (17/17). No complication occurred during or after the procedures. The median follow-up duration was 167 [interquartile range (IQR), 48-576] days. Stent malfunction occurred after 58.8% (10/17) of the procedures, including six occurrences of stent migration and four of benign tissue hyperplasia. Surgical removal of the migrated stents was performed in two patients. Recurrence of symptoms occurred after 64.7% (11/17) of the procedures. The median stent dwell and recurrence-free times were 32 (IQR, 20-193) and 68 (IQR, 38-513) days, respectively.

Conclusion: Fluoroscopic SEMS placement may be effective and safe for treating postoperative nonanastomotic strictures, but stent malfunction and recurrence are major drawbacks.

Advances In Knowledge: SEMS placement is effective and relatively safe in patients with postoperative nonanastomotic strictures in the proximal small bowel. Patients section and counseling is highly encouraged.
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http://dx.doi.org/10.1259/bjr.20180957DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6592082PMC
June 2019

A Novel Full Sense Device to Treat Obesity in a Porcine Model: Preliminary Results.

Obes Surg 2019 05;29(5):1521-1527

Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea.

Purpose: To evaluate the technical feasibility, safety, and efficacy of a novel full sense device (FSD) for the treatment of obesity in a porcine model.

Materials And Methods: The novel FSD comprised a self-expanding metallic esophageal stent connected to a star-shaped nitinol disk. Three types of FSD were used: fully covered (type A), fully covered with barbs (type B), and uncovered with barbs (type C). Nine juvenile pigs were divided into two groups: FSD (n = 6) and control (n = 3). FSD type A was placed in the FSD group. In case of migration, either FSD type B or type C was then randomly placed. Food intake was monitored daily. Weight changes and ghrelin hormone levels were monitored weekly for 12 weeks.

Results: FSD placement was technically successful in all pigs. All FSDs except one migrated to the stomach within 1 week after placement. The pig in which the FSD was retained showed decreased food intake in the first week after FSD placement, and there was a difference in the final weight between the FSD pig and control pigs. The percentage of weight gain was 116.6% in the control group and 105.3% in the FSD pig.

Conclusion: FSD placement under fluoroscopic and endoscopic guidance is technically feasible and safe in a porcine model. The uncovered FSD appears to decrease food intake and reduce the rate of weight gain. However, the high FSD migration rate is not encouraging.
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http://dx.doi.org/10.1007/s11695-018-03692-5DOI Listing
May 2019

Development and Evaluation of a New Volume Measuring System in Mouse Tail Lymphedema Model.

Lymphat Res Biol 2019 08 18;17(4):402-412. Epub 2018 Dec 18.

1Biorobotics Laboratory, Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea.

Secondary lymphedema is a common complication of parasitization and breast or gynecologic cancer therapy; however, options for the treatment of lymphedema are ineffective and limited. A mouse tail model is one of the most successful animal models for a lymphatic study. Lymphedema of the mouse tail is characterized by increases in the volume of the extremity caused by accumulation of tissue fluid, proliferation of fibroblasts and adipocytes, and excessive production of collagen. However, the study of lymphedema using mouse has been plagued with difficulty in directly assessing physiologic changes owing to limitations in the measurement of the mouse tail volume. Furthermore, the mouse tail volume cannot be obtained using the general measurement method such as volumetric water displacement. Lymphatic researchers have used the truncated cone formula to approximate the volume as used in the numerical approximation of a cylindrical figure. Although this formula is simple and easy to use, it has difficulties of repeatability and accuracy because the measurement procedure is highly subjective and the accuracy depends on the number of divided segments on the tail. In this article, two novel volumetric measurement methods for the mouse tail model were introduced. The methods were evaluated and compared using three mice with surgically created lymphedema on the tails. The two continuous measuring methods showed a possibility to improve the conventional method by continuous measurement using visual and physical detecting methods. The proposed methods facilitate the extraction of longitudinal section-specific information, which can be an important clue in a lymphatic study.
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http://dx.doi.org/10.1089/lrb.2018.0019DOI Listing
August 2019

In Vivo Fluorescence Microendoscopic Monitoring of Stent-Induced Fibroblast Cell Proliferation in an Esophageal Mouse Model.

J Vasc Interv Radiol 2018 12 26;29(12):1756-1763. Epub 2018 Sep 26.

Department of Biomedical Engineering Research Center, and Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88, Olymic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea. Electronic address:

Purpose: To evaluate the feasibility of self-expanding metal stent (SEMS) placement and fluorescence microendoscopic monitoring for determination of fibroblast cell proliferation after stent placement in an esophageal mouse model.

Materials And Methods: Twenty fibroblast-specific protein (FSP)-1 green fluorescent protein (GFP) transgenic mice were analyzed. Ten mice (Group A) underwent SEMS placement, and fluoroscopic and fluorescence microendoscopic images were obtained biweekly until 8 weeks thereafter. Ten healthy mice (Group B) were used for control esophageal values.

Results: SEMS placement was technically successful in all mice. The relative average number of fibroblast GFP cells and the intensities of GFP signals in Group A were significantly higher than in Group B after stent placement. The proliferative cellular response, including granulation tissue, epithelial layer, submucosal fibrosis, and connective tissue, was increased in Group A. FSP-1-positive cells were more prominent in Group A than in Group B.

Conclusions: SEMS placement was feasible and safe in an esophageal mouse model, and proliferative cellular response caused by fibroblast cell proliferation after stent placement was longitudinally monitored using a noninvasive fluorescence microendoscopic technique. The results have implications for the understanding of proliferative cellular response after stent placement in real-life patients and provide initial insights into new clinical therapeutic strategies for restenosis.
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http://dx.doi.org/10.1016/j.jvir.2018.06.024DOI Listing
December 2018

EW-7197, an oral transforming growth factor β type I receptor kinase inhibitor, for preventing peritoneal adhesion formation in a rat model.

Surgery 2018 11 29;164(5):1100-1108. Epub 2018 Aug 29.

Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Background: EW-7197 is an oral transforming growth factor β type I receptor kinase inhibitor currently undergoing phase I clinical trials for cancer treatment in the United States. This study evaluates whether EW-7197 prevents peritoneal adhesion formation in a rat model.

Methods: Forty-eight female Wistar rats underwent peritoneal adhesion induction by the creation of peritoneal ischemic buttons and were randomly divided into 4 groups of 12 each. The control group received 0.3 mL vehicle by oral gavage once daily for 7 days after adhesion induction. The 10 mg and 20 mg groups received 10 or 20 mg/kg EW-7197 phosphate dissolved in 0.3 mL vehicle by oral gavage once daily for 7 days after adhesion induction. The rebound group received 20 mg/kg EW-7197 phosphate dissolved in 0.3 mL vehicle by oral gavage once daily for 7 days after adhesion induction followed by 0.3 mL vehicle only by gavage once daily for an additional 21 days. After the respective treatments were completed, the animals were euthanized.

Results: All rats survived until the end of the study without complications. EW-7197 reduced the incidence, quality, and tenacity of peritoneal adhesions in a dose-dependent manner. Fibrosis and collagen production were reduced in EW-7197-treated peritoneal ischemic buttons. Transforming growth factor β/Smad2/3 signaling and mesothelial-to-mesenchymal transition were inhibited in EW-7197-treated peritoneal ischemic buttons. Discontinuation of EW-7197 was not associated with rebound effects.

Conclusion: EW-7197 prevented peritoneal adhesion formation potentially via inhibition of transforming growth factor β1/Smad2/3-induced mesothelial-to-mesenchymal transition in a rat model.
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http://dx.doi.org/10.1016/j.surg.2018.07.005DOI Listing
November 2018

Fluoroscopic balloon diameter measurement at different pressures during Eustachian balloon dilation.

Clin Otolaryngol 2018 12 12;43(6):1573-1577. Epub 2018 Sep 12.

Department of Otorhinolaryngology-Head & Neck Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Objectives: To measure the diameter of inflated balloons at different pressures during Eustachian tube (ET) balloon dilation under fluoroscopic guidance.

Design: Prospective cohort study.

Setting: Tertiary academic referral centre.

Participants: Eighteen patients who underwent ET balloon dilation with use of a balloon catheter, 20 mm long and 6 mm in diameter, under combined endoscopic and fluoroscopic guidance.

Main Outcome Measures: Degrees of inflation at three different portions (proximal, middle and distal) of the balloon at controlled pressures (3, 5, 8 and 10 atmospheres [atm]) and at the maximum pressure manually applied.

Results: The mean proximal, middle and distal diameters of the inflated balloons were 5.3 ± 0.4 mm, 5.3 ± 0.4 mm and 4.9 ± 0.5 mm at 10 atm. The distal diameters were significantly smaller than middle and proximal diameters at all the pressures (P < 0.01). When compared to the distal diameter (100%, 4.9 ± 0.5 mm) at 10 atm, the distal diameters were 73% (3.6 ± 0.6 mm) at 3 atm, 88% (4.3 ± 0.5 mm) at 5 atm and 96% (4.7 ± 0.4 mm) at 8 atm. The distal diameter (4.1 ± 0.3 mm) at the maximum pressure manually applied was in between those at 3 and 5 atm.

Conclusions: The distal diameter of the balloon increased significantly as a function of the pressure and most (88%) inflation occurred at a low pressure of 5 atm, which was sufficient to inflate the distal diameter of the balloon more than 3 mm. The manual pressurisation could inflate a balloon by as much as could be expected, at between 3 and 5 atm.
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http://dx.doi.org/10.1111/coa.13218DOI Listing
December 2018

Fluoroscopy-Guided Peroral Placement of a Self-Expandable Metallic Stent for Malignant Jejunal Obstruction in a Non-surgically Altered Stomach.

Cardiovasc Intervent Radiol 2019 Jan 7;42(1):145-149. Epub 2018 Aug 7.

Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap 2-dong, Songpa-gu, Seoul, 05505, Republic of Korea.

Malignant small bowel obstruction is a common and distressing complication in advanced cancer patients. Recently, stent placement was reported to be a safe and effective alternative treatment. However, there are only a few case reports associated with stent placement in malignant jejunal obstruction. Furthermore, most patients had a history of gastrectomy before stent placement, which shortens the catheterization pathway. In our case series, we present five cases of malignant proximal jejunal obstruction in a non-surgically altered stomach in the management of fluoroscopy-guided self-expandable metallic stent placement and discuss the interventional management and clinical outcomes. LEVEL OF EVIDENCE: Level 4, Case Series.
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http://dx.doi.org/10.1007/s00270-018-2048-3DOI Listing
January 2019

Nanofunctionalized Stent-Mediated Local Heat Treatment for the Suppression of Stent-Induced Tissue Hyperplasia.

ACS Appl Mater Interfaces 2018 Sep 21;10(35):29357-29366. Epub 2018 Aug 21.

Department of Radiology, Feinberg School of Medicine , Northwestern University , Chicago , Illinois 60611 , United States.

Current therapeutic strategies are insufficient for suppressing stent-induced restenosis. Here, branched gold nanoparticles (BGNP)-coated self-expandable metallic stents (SEMSs) were developed for a local heat-induced suppression of stent-related tissue hyperplasia. Our polydopamine (PDA) coating on SEMS allowed BGNP crystal growth on the surface of SEMSs. The prepared BGNP-coated SEMS showed effective local heating under near-infrared laser irradiation. The effectiveness of BGNP-coated SEMSs for suppressing stent-related tissue hyperplasia was demonstrated in a rat esophageal model ( n = 52). BGNP-coated SEMS placement under fluoroscopic guidance was technically successful in all rats. The placed BGNP-coated SEMS in rat esophagus achieved three different local heat dose ranges (50, 65, and 80 °C) under fluoroscopic image-guided local irradiation. Follow-up endoscopic examination readily monitored the local heating and observed significantly decreased tissue hyperplasia at 4 weeks of local heat treatments (50 and 65 °C). Finally, Western blot, histology, immunohistochemistry (HSP70, αSMA, and TUNEL), and immunofluorescence (Ki67 and BrdU) analyses along with the statistical analysis confirmed that optimized BGNP-coated SEMS-mediated local heat treatments inducing the expression of anti-inflammatory HSP70 effectively suppresses tissue hyperplasia after stent placement in the esophagus. Our local heating with nanofunctionalized stents represents a promising new approach for suppressing stent-related tissue hyperplasia.
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http://dx.doi.org/10.1021/acsami.8b09819DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7050633PMC
September 2018

Transnasal Placement of a Balloon-Expandable Metallic Stent: Human Cadaver Study of the Eustachian Tube.

J Vasc Interv Radiol 2018 08 29;29(8):1187-1193. Epub 2018 Jun 29.

Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea. Electronic address:

Purpose: To investigate the technical feasibility of stent placement in the cartilaginous portion of the Eustachian tube (ET).

Materials And Methods: Twelve ETs of 6 cadavers were used. Two different-sized stents were placed on either the right (2.5 mm in diameter) or left (3.5 mm in diameter) side of the ET. The procedural feasibility was assessed by subtraction Eustachian tubography, computed tomography before and after the procedure, and fluoroscopic and endoscopic images. The stent location, inner luminal diameter of the stented ET, radiation dose, procedural time, and fluoroscopy time were analyzed.

Results: Stent placement was successful in 11 of 12 cadaveric specimens without procedure-related complications. In the 1 specimen, the balloon catheter with crimped stent was passed into the bony canal of the ET without any resistance. The distal end of the stent was located in the middle ear cavity. Stents were located within the cartilaginous portion of the ET (n = 1), the proximal tip bridging the nasopharyngeal orifice of the ET (n = 5), or the proximal end of the stent protruded from the tubal orifice (n = 5). The mean luminal diameter in the outer segment was significantly smaller than in the middle (P < .001) and inner (P < .001) segments. The mean procedure time was 128 ± 37 seconds. The mean radiation dose and fluoroscopy time of each cadaver were 3235.4 ± 864.8 cGy/cm and 139 ± 49 seconds, respectively.

Conclusions: Stent placement of the ET under endoscopic and fluoroscopic guidance is technically feasible in a human cadaver model.
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http://dx.doi.org/10.1016/j.jvir.2018.03.029DOI Listing
August 2018

Oesophageal stenting: Status quo and future challenges.

Br J Radiol 2018 Nov 27;91(1091):20170935. Epub 2018 Jun 27.

4 Department of Radiology, The Christie NHS Foundation Trust , Manchester , UK.

Oesophageal stents are widely used for palliating dysphagia from malignant obstruction. They are also used with increasing frequency in the treatment of oesophageal perforation, as well as benign strictures from a variety of causes. Improved oncological treatments have led to prolonged survival of patients treated with palliative intent; as a consequence, stents need to function and last longer in order to avoid repeat procedures. There is also increasing need for meticulous procedure planning, careful selection of the device most appropriate for the individual patient and planned follow-up. Furthermore, as more patients are cured, there will be more issues with resultant long-term side-effects, such as recalcitrant strictures due to radiotherapy or anastomotic scarring, which will have to be addressed. Stent design needs to keep up with the progress of cancer treatment, in order to offer patients the best possible long-term result. This review article attempts to illustrate the changing realities in oesophageal stenting, differences in current stent designs and behaviour, as well as the pressing need to refine and modify devices in order to meet the new challenges.
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http://dx.doi.org/10.1259/bjr.20170935DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6475941PMC
November 2018

Developmental endothelial locus-1 prevents development of peritoneal adhesions in mice.

Biochem Biophys Res Commun 2018 06 25;500(3):783-789. Epub 2018 Apr 25.

Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul, Republic of Korea. Electronic address:

Postoperative peritoneal adhesions, fibrous bands formed in the peritoneal cavity following surgery, represent a common, challenging and costly problem faced by surgeons and patients, for which effective therapeutic options are lacking. Since aberrant inflammation is one of the key mechanisms underlying peritoneal adhesion formation, here we set out to study the role of developmental endothelial locus-1 (Del-1), which has been recently identified as an endogenous inhibitor of inflammation, in the formation of postoperative peritoneal adhesions using a mouse model of peritoneal adhesions induced by ischemic buttons. Del-1-deficient mice had a higher incidence of adhesions, and their adhesions had higher quality and tenacity scores. Del-1 deficiency also led to enhanced inflammation mediators and collagen production. Finally, Del-1 supplementation decreased the incidence and severity of postoperative peritoneal adhesions. Taken together, these results indicate a protective role for Del-1 in postoperative peritoneal adhesion formation.
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http://dx.doi.org/10.1016/j.bbrc.2018.04.158DOI Listing
June 2018

Fluoroscopic subtraction Eustachian tubography: initial feasibility test in a cadaver model.

Eur Radiol 2018 Sep 4;28(9):3685-3691. Epub 2018 Apr 4.

Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea.

Objectives: To evaluate the technical feasibility of direct Eustachian tube catheterisation and subtraction Eustachian tubography in a cadaver model.

Methods: A total of 12 separate sessions were performed on both sides of the Eustachian tube (ET) in six human cadavers. Cadavers were positioned for the submentovertical view on a fluoroscopy table. Endoscopy-guided ET selection was used in the first three cadavers, whereas fluoroscopy-guided ET selection was used in the remaining three. Eustachian tubography was performed by injecting 2 ml of contrast media through a 5-Fr catheter. We recorded the success of ET selection, number of attempts, procedure time, and tubography quality using native and subtraction images (range, 0-3).

Results: Both endoscopy- and fluoroscopy-guided selections were successfully performed in five of six sessions (83.3%). There were no statistically significant differences between the endoscopy- and fluoroscopy-guided procedures in terms of the number of attempts, procedure time, rate of immediate contrast leak to the middle ear cavity, and quality of tubography (p > 0.05). An excellent quality of tubography was obtained in 83.3% (10 of 12 sessions) of subtraction images and in 33.3% (4 of 12 sessions) of native images. The tubography quality score was significantly higher for the subtraction images than for the native images (p = 0.04).

Conclusion: Subtraction Eustachian tubography using direct catheterisation seems to be technically feasible. The entire ET can be well visualised; thus, this technique can be used as a simple tool for assessment of ET function and anatomy.

Key Points: • Direct catheterisation of the Eustachian tube is technically feasible. • The entire Eustachian tube could be well visualised by direct Eustachian tubography. • Subtraction Eustachian tubography images have better image quality than native images. • Subtraction Eustachian tubography can provide objective assessment of ET function and anatomy.
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http://dx.doi.org/10.1007/s00330-018-5392-4DOI Listing
September 2018

Fluoroscopic Gastroduodenal Stent Placement in 55 Patients with Endoscopic Stent Placement Failure.

Cardiovasc Intervent Radiol 2018 Aug 14;41(8):1233-1240. Epub 2018 Mar 14.

Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea.

Purpose: To evaluate the technical feasibility and clinical effectiveness of fluoroscopic self-expandable metal stent (SEMS) placement in malignant gastroduodenal obstructions after failed endoscopic SEMS placement.

Materials And Methods: Between September 2010 and July 2017, 874 patients underwent endoscopic SEMS placement for dysphagia caused by malignant gastroduodenal obstructions. Endoscopic SEMS placement failed in 55 of 874 patients (6.3%). These patients were referred for fluoroscopic SEMS placement. In case of failed fluoroscopic SEMS placement, combined endoscopic and fluoroscopic SEMS placement was attempted at the same setting.

Results: Fluoroscopic SEMS placement was technically successful in 40 of 55 patients (72.7%). Combined endoscopic and fluoroscopic SEMS placement was technically successful in 6 of 15 patients with fluoroscopic SEMS placement failure. Failures in the nine patients were due to complete obstruction (n = 5) and acute angulation at the stricture site (n = 4). The overall technical success rate was 83.6% (46/55). Clinical success was achieved in 95.6% of patients (44/46). Complications occurred in 7 of 46 patients (15.2%), including tumor overgrowth (n = 3), SEMS migration (n = 3), and bleeding (n = 1). The median SEMS patency and patient survival periods were 515 (95% confidence interval (CI), 266.6-761.5) and 83 (95% CI 60.6-105.4) days, respectively.

Conclusions: Fluoroscopic SEMS placement is technically feasible and clinically effective in cases of endoscopic SEMS placement failure. A combined endoscopic and fluoroscopic approach increases the technical success rate after failure of the endoscopic or fluoroscopic approach.

Level Of Evidence: Level IV.
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http://dx.doi.org/10.1007/s00270-018-1933-0DOI Listing
August 2018

EW-7197 eluting nano-fiber covered self-expandable metallic stent to prevent granulation tissue formation in a canine urethral model.

PLoS One 2018 15;13(2):e0192430. Epub 2018 Feb 15.

Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.

Purpose: To evaluate an EW-7197-eluting nanofiber-covered stent (NFCS) for suppressing granulation tissue formation after stent placement in a canine urethral model.

Materials And Methods: All experiments were approved by the committee of animal research. A total of 12 NFCSs were placed in the proximal and distal urethras of six dogs. Dogs were divided into two groups with 3 dogs each. The control stent (CS) group received NFCSs and the drug stent (DS) group received EW-7197 (1000 μg)-eluting NFCSs. All dogs were sacrificed 8 weeks after stent placement Histologic findings of the stented urethra were compared using the Mann-Whitney U test.

Results: Stent placement was technically successful in all dogs without procedure-related complications. On urethrographic analysis, the mean luminal diameter was significantly larger in the DS group than in the CS group at 4 and 8 weeks after stent placement (all p < 0.001). On histological examination, mean thicknesses of the papillary projection, thickness of submucosal fibrosis, number of epithelial layers, and degree of collagen deposition were significantly lower in the DS group than in the CS group (all p < 0.001), whereas the mean degree of inflammatory cell infiltration was not significantly different (p > 0.05).

Conclusion: The EW-7197-eluting NFCS is effective and safe for suppressing granulation tissue formation after stent placement in a canine urethral model.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0192430PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5813937PMC
April 2018

Acute Biliary Obstruction After Gastroduodenal Covered Self-Expanding Metallic Stent Placement in Patients with Previous Biliary Stent Placement for Periampullary Cancer: Frequency and Protective Factors.

Cardiovasc Intervent Radiol 2018 Apr 7;41(4):603-609. Epub 2017 Nov 7.

Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea.

Purpose: We aimed to evaluate the frequency and protective factors of acute biliary obstruction in patients with biliary stent placement followed by gastroduodenal covered self-expandable metallic stent (SEMS) placement owing to progression of periampullary cancer.

Materials And Methods: We retrospectively reviewed 58 patients. Total bilirubin and alkaline phosphatase (ALP) levels before and after gastroduodenal covered SEMS placement were evaluated. The incidence of acute biliary obstruction correlated to age, sex, biliary stent length and type, and longitudinal and axial locations of the lower end of the biliary stent was evaluated.

Results: Postprocedural total bilirubin and ALP levels were significantly higher than preprocedural levels (2.30 ± 2.53 vs. 1.53 ± 1.48 mg/dL; P = 0.008, 331.0 ± 248.8 vs. 258.4 ± 195.2 IU/L; P = 0.008, respectively). The increase in bilirubin levels was not statistically significant in female patients or patients with a biliary stent length ≥ 6 cm or longitudinal location of the lower end of the biliary stent distal to the lower end of the gastroduodenal stent (P > 0.05). Seven patients (12.1%) developed acute biliary obstruction. No patients with the lower end of the biliary stent located distal to the lower end of the gastroduodenal stent developed acute biliary obstruction (P = 0.012).

Conclusion: The incidence of acute biliary obstruction was 12.1% among patients with biliary stent placement followed by gastroduodenal covered SEMS placement. Longitudinal location of the lower end of the biliary stent distal to the lower end of the gastroduodenal stent was a protective factor.
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http://dx.doi.org/10.1007/s00270-017-1823-xDOI Listing
April 2018
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