Background: Warm ischemia is a major contributor to ischemic cholangiopathy and non-anastomotic biliary strictures (NAS) after liver transplantation, particularly in donation-after-circulatory-death grafts. However, the isolated impact of warm ischemia on peribiliary fibrosis is difficult to delineate because clinical settings involve overlapping effects of cold ischemia, reperfusion injury, and alloimmunity. This study aimed to establish a non-transplant rat model that isolates warm ischemic biliary injury and to compare the antifibrotic effects of rapamycin and tacrolimus. Methods: Warm ischemia was induced in Sprague–Dawley rats by ligating both ends of the peribiliary vascular plexus and the hepatic artery, followed by 30 minutes of portal vein clamping. Rats were randomly assigned to control, tacrolimus (1 mg/kg/day), or rapamycin (1 mg/kg/day) groups (n=15 per group). Serum alanine aminotransferase, alkaline phosphatase, gamma-glutamyl transferase, and total bilirubin were measured serially. Hematoxylin and eosin (H&E) and Sirius red staining were performed at 1, 3, and 6 weeks. Peribiliary fibrosis was quantified using digital image analysis of collagen area fraction. Results: Warm ischemia induced acute hepatobiliary injury with transient enzyme elevations, but no significant intergroup differences were observed. Histologically, biliary epithelial proliferation and collagen deposition increased progressively and became prominent at 6 weeks. At this time point, fibrosis ratios differed significantly (overall p=0.002): controls showed the highest fibrosis (4.8%), followed by tacrolimus (2.4%) and rapamycin (1.7%). Both immunosuppressants significantly reduced fibrosis compared with controls (p<0.05), whereas the difference between tacrolimus and rapamycin was not significant. Conclusion This warm ischemia model demonstrates that isolated ischemic injury alone can induce progressive peribiliary fibrosis. Rapamycin and tacrolimus attenuated fibrosis, with rapamycin producing the lowest collagen deposition. These findings provide mechanistic insight into ischemic cholangiopathy after liver transplantation—particularly in donation after circulatory death grafts—and underscore the need for further studies using models that incorporate cold ischemia, reperfusion, and alloimmune factors.

Purpose: Weight reduction (WR) can reduce liver volume, affecting the graft-to-recipient weight ratio (GRWR). This study aimed to evaluate the decrease in liver volume after WR and analyze risk factors affecting liver volume reduction in potential liver donors with steatosis. Methods: We retrospectively reviewed data of 147 potential liver donors with steatosis who participated in a WR program prior to liver transplantation between January 2016 and December 2021. Total liver volume (TLV) was measured using CT and MRI. Risk factors for large liver volume reduction (≥10%) were analyzed using multivariate logistic regression. Results: Ninety-seven donors (66.0%) underwent donor hepatectomy after WR. Liver volumes showed a statistically significant decrease (from 1,399.6 ± 315.4 mL to 1,283.6 ± 271.2 mL, P < 0.05). Thirty-eight donors (42.7%) showed large liver volume reduction. There was a more significant reduction in weight, AST, and ALT in the large liver volume reduction group than in the small liver volume reduction group (all P < 0.05). WR percentage and ALT abnormalities were independent risk factors for large liver volume reduction (odds ratio, 1.184 [95% confidence interval, 1.054–1.329] and odds ratio, 5.502 [95% confidence interval, 1.660–18.229], respectively; all P < 0.05). Conclusion Potential liver donors with 7% or more WR or ALT abnormality require liver volume/GRWR remeasurement after WR to ensure adequate graft size and prevent small-for-size syndrome.

Purpose: Right lobe living donor liver transplantation (LDLT) with dual portal veins (PVs) remains technically challenging.This study aimed to identify independent risk factors for PV complications. Methods: We retrospectively analyzed 111 recipients of dual PV LDLT between 2011 and 2020. Recipient characteristics, anatomical geometry, and surgical factors were evaluated. Outcomes were overall PV complications and major PV complications (Clavien-Dindo grade ≥III). Logistic regression was performed. Results: PV complications developed in 41 patients (36.9%), including 16 major events (14.4%). Univariate analysis revealed associations with right posterior PV (RPPV) diameter, axial angle, and coronal angle. On multivariate analysis, larger RPPV diameter (odds ratio [OR], 1.79; P = 0.041) and wider axial angle (OR, 1.08; P = 0.015) were independent predictors of major PV complications. Reconstruction method was not significant. Patients with overall major Clavien-Dindo grade ≥IIIcomplications had inferior 100-month survival (80% vs. 100%; P = 0.014, log-rank test). Conclusion In dual PV LDLT, anatomical geometry—specifically RPPV diameter and axial angle—independently predicts major PV complications, whereas surgical technique does not. Preoperative 3-dimensional imaging and anatomical risk stratification should inform donor selection and surgical planning.

Purpose: The male predominance in the incidence of gastric cancer (GC) is established; however, sex differences in the prognosis of GC remain controversial. As such, this study analyzed the prognosis of patients with GC based on age and sex. Materials and Methods: Data from 14,739 patients diagnosed with GC at Seoul National University Bundang Hospital between 2003 and 2023 were analyzed. Baseline characteristics, histological types of GC, overall and GC-specific survival rates (age and stage stratification), and associated risk factors were analyzed. Results: Females were significantly younger (p < 0.001) and exhibited more gastric body cancers (p < 0.001) and tumors with diffuse-type or poorly differentiated histology (p < 0.001) than males. Females exhibited an advantage over males in terms of overall survival (p=0.004), but not in GC-specific survival. However, age stratification revealed significant sex differences, that females < 50 years of age exhibited survival disadvantages (p < 0.001); however, this trend was reversed with age, and females > 60 years exhibited survival advantages (p < 0.001) for both overall and GC-specific survival. This may be explained by the lower ratio of diffuse-type GC as females age. Furthermore, in the analysis according to stage, females with stage IV disease exhibited significant survival disadvantages, with significantly younger age and a higher proportion of diffuse-type GC which exhibits aggressive features, resulting in poorer survival than in males. Conclusion Age and stage stratification revealed significant differences in survival between the sexes, which can be helpful for public health strategies.

Purpose: This study aimed to evaluate the role of hepatic resection in patients with objective responses after combined transarterial chemoembolization (TACE) and radiotherapy (RT) for hepatocellular carcinoma (HCC) with macroscopic vascular invasion (MVI). Materials and Methods: We retrospectively reviewed the patients treated with combined TACE and RT for HCC with MVI between 2010 and 2015. Some of the patients with objective responses underwent hepatic resection or liver transplantation; to investigate the impact of surgery, patients with objective responses who did not undergo surgery were selected as the control group. Survival outcomes were compared using a propensity score–based stabilized inverse probability of treatment weighting method. Results: Out of the 170 patients with objective responses after combined TACE and RT, 41 patients underwent surgery, including eight liver transplantations. The unweighted surgery group was younger and had a higher proportion of solitary tumors and unilateral vascular involvement. After adjustment, the 3-year overall survival (OS) rates were 61.0% and 28.6% in the surgery and non-surgery groups, respectively. The most important prognostic factor for OS was surgery (adjusted Cox hazard ratio [HR], 0.28; 95% confidence interval [CI], 0.17 to 0.46; p < 0.001). Complete response after TACE and RT (vs. partial response) was also a significant prognostic factor for OS (adjusted HR, 0.41; 95% CI, 0.27 to 0.61; p < 0.001). There was no surgical mortality. Four patients (9.8%) required additional surgery due to bleeding or graft failure. Conclusion Hepatic resection was significantly associated with improved OS in patients who showed objective responses after receiving combined TACE and RT for HCC with MVI.

Vaccines are highly effective, but rare or delayed adverse events following immunization (AEFIs) require post-licensure surveillance beyond clinical trials. Korea lacks a comprehensive, active, database-based framework, yet key assets exist: nationwide claims databases (National Health Insurance Service/Health Insurance Review and Assessment Service), the national immunization registry (Korea Disease Control and Prevention Agency’s Immunization Registry Information System) for National Immunization Program (NIP) and non-NIP vaccines, and increasingly standardized hospital electronic health records.We propose a federated, code to data architecture with data linkages between these data.Implementation should adopt a common data model (CDM), standardized case definitions, latency accounting, and transparent public reporting under strong privacy governance. Major challenges include multi step administrative approvals for data linkage, incomplete capture of adult non-NIP vaccinations, heterogeneous hospital data structures, and strict data protection constraints. Strategic priorities are to streamline statutory and administrative processes for public health use, mandate or enable claims-based capture of adult vaccinations, enhance CDM based interoperability, and develop secure hubs for aggregated outputs. With these measures, Korea will be well positioned to establish a scalable active surveillance system capable of detecting rare AEFIs, supporting transparent and evidence-based communication, and ensuring equitable injury compensation grounded in domestic data.

Background/Aims: The study investigated the incidence, risk factors, and clinical outcomes of chronic antibiotic-refractory pouchitis (CARP) in Korean patients with ulcerative colitis (UC). Methods: This single-center retrospective study included patients with UC who underwent total proctocolectomy with ileal pouch-anal anastomosis at the Asan Medical Center in Korea between January 1987 and December 2022. The primary outcomes were endoscopic remission and pouch failure. The Cox’s proportional hazard model was used to identify the risk factors for CARP. Results: The clinical data of 232 patients were analyzed. The most common cause of surgery was steroid refractoriness (50.9%), followed by dysplasia/colorectal cancer (26.7%). Among 74 patients (31.9%) with chronic pouchitis (CP), 31 (13.4%) had CARP, and 43 (18.5%) had chronic antibiotic-dependent pouchitis (CADP). The most frequent endoscopic phenotype was focal inflammation of the pouch (CP, 47.3%; CARP, 35.5%; CADP, 55.8%). Patients with CARP were less likely to use concomitant probiotics than patients with CADP (29.0% vs 72.1%, p<0.01). The endoscopic remission rate of CP, CARP, and CADP was 14.9%, 9.7%, and 18.6%, respectively.The pouch failure rate associated with CP, CARP, and CADP was 13.5%, 16.1%, and 11.6%, respectively. Current smoking status (adjusted hazard ratio [aHR], 2.96; 95% confidence interval [CI], 1.27 to 6.90; p=0.01) and previous use of biologics/small molecules (aHR, 2.40; 95% CI, 1.05 to 5.53; p=0.04) were significantly associated with CARP development. Conclusions UC patients who were current smokers and previously used biologics/small molecules had a higher risk of developing CARP. Concomitant use of probiotics was less likely to be associated with CARP development.

Background: and Purpose Treatments for neuromyelitis optica spectrum disorder (NMOSD) such as eculizumab, ravulizumab, satralizumab, and inebilizumab have significantly advanced relapse prevention, but they remain expensive. Rituximab is an off-label yet popular alternative that offers a cost-effective solution, but its real-world efficacy needs better quantification for guiding the application of newer approved NMOSD treatments (ANTs). This study aimed to determine real-world rituximab failure rates to anticipate the demand for ANTs and aid in resource allocation. Methods: We conducted a nationwide retrospective study involving 605 aquaporin-4-antibody-positive NMOSD patients from 22 centers in South Korea that assessed the efficacy and safety of rituximab over a median follow-up of 47 months. Results: The 605 patients treated with rituximab included 525 (87%) who received continuous therapy throughout the follow-up period (median=47 months, interquartile range=15–87 months). During this period, 117 patients (19%) experienced at least 1 relapse. Notably, 68 of these patients (11% of the total cohort) experienced multiple relapses or at least 1 severe relapse.Additionally, 2% of the patients discontinued rituximab due to adverse events, which included severe infusion reactions, neutropenia, and infections. Conclusions This study has confirmed the efficacy of rituximab in treating NMOSD, as evidenced by an 87% continuation rate among patients over a 4-year follow-up period. Nevertheless, the occurrence of at least one relapse in 19% of the cohort, including 11% who experienced multiple or severe relapses, and a 2% discontinuation rate due to adverse events highlight the urgent need for alternative therapeutic options.