BACKGROUND: Regulatory T cells (Tregs) are essential for maintaining immune homeostasis and facilitating tissue regeneration by fostering an environment conducive to tissue repair. However, in damaged tissues, excessive inflammatory responses can overwhelm the immunomodulatory capacity of Tregs, compromising their functionality and potentially hindering effective regeneration. Mesenchymal stem cells (MSCs) play a key role in enhancing Treg function. MSCs enhance Treg activity through indirect interactions, such as cytokine secretion, and direct interactions via membrane proteins. METHODS: This review examines the regenerative functions of Tregs across various tissues, including bone, cartilage, muscle, and skin, and explores strategies to enhance Treg functionality using MSCs. Advanced techniques, such as the overexpression of relevant genes in MSCs, are highlighted for their potential to further enhance Treg function. Additionally, emerging technologies utilizing extracellular vesicles (EVs) and cell membrane-derived vesicles derived from MSCs offer promising alternatives to circumvent the potential side effects associated with live cell therapies. This review proposes approaches to enhance Treg function and promote tissue regeneration and also outlines future research directions. RESULTS AND CONCLUSION: This review elucidates recent technological advancements aimed at enhancing Treg function using MSCs and examines their potential to improve tissue regeneration efficiency.

Purpose: Adjuvant treatment for craniopharyngioma after surgery is controversial. Adjuvant external beam radiation therapy (EBRT) can increase the risk of long-term sequelae. Stereotactic radiosurgery (SRS) is used to reduce treatment-related toxicity.In this study, we compared the treatment outcomes and toxicities of adjuvant therapies for craniopharyngioma. Materials and Methods: We analyzed patients who underwent craniopharyngioma tumor removal between 2000 and 2017. Of the 153 patients, 27 and 20 received adjuvant fractionated EBRT and SRS, respectively. We compared the local control (LC), progression-free survival (PFS), and overall survival between groups that received adjuvant fractionated EBRT, SRS, and surveillance. Results: The median follow-up period was 77.7 months. For SRS and surveillance, the 10-year LC was 57.2% and 57.4%, respectively. No local progression was observed after adjuvant fractionated EBRT. One patient in the adjuvant fractionated EBRT group died owing to glioma 94 months after receiving radiotherapy (10-year PFS: 80%). The 10-year PFS was 43.6% and 50.7% in the SRS and surveillance groups, respectively. The treatment outcomes significantly differed according to adjuvant treatment in nongross total resection (GTR) patients. Additional treatment-related toxicity was comparable in the adjuvant fractionated EBRT and other groups. Conclusion Adjuvant fractionated EBRT could be effective in controlling local failure, especially in patients with non-GTR, while maintaining acceptable treatment-related toxicity.

Purpose: We assessed human papillomavirus (HPV) genotype-based risk stratification and the efficacy of cytology testing for cervical cancer screening in patients with atypical squamous cells of undetermined significance (ASCUS)/low-grade squamous intraepithelial lesion (LSIL). Materials and Methods: Between 2010 and 2021, we monitored 1,273 HPV-positive women with ASCUS/LSIL every 6 months for up to 60 months. HPV infections were categorized as persistent (HPV positivity consistently observed post-enrollment), negative (HPV negativity consistently observed post-enrollment), or non-persistent (neither consistently positive nor negative). HPV genotypes were grouped into high-risk (Hr) groups 1 (types 16, 18, 31, 33, 45, 52, and 58) and 2 (types 35, 39, 51, 56, 59, 66, and 68) and a low-risk group. Hr1 was subdivided into types (a) 16 and 18; (b) 31, 33, and 45; and (c) 52 and 58. Cox regression and machine learning (ML) algorithms were used to analyze progression rates. Results: Among 1,273 participants, 17.6% with persistent HPV infections experienced disease progression versus no progression in the HPV-negative group (p < 0.001). Cox analysis revealed the highest hazard ratios (HRs) for Hr1-a (11.6, p < 0.001), followed by Hr1-b (9.26, p < 0.001) and Hr1-c (7.21, p < 0.001). HRs peaked at 12-24 months, with Hr1-a maintaining significance at 24-36 months (10.7, p=0.034). ML analysis identified the final cytology change pattern as the most significant factor, with 14-15 months the optimal time for detecting progression from the first examination. Conclusion In ASCUS/LSIL cases, follow-up strategies should be based on HPV risk types. Annual follow-up was the most effective monitoring for detecting progression/regression.

The common data model (CDM) has found widespread application in healthcare studies, but its utilization in cancer research has been limited. This article describes the development and implementation strategy for Cancer Clinical Library Databases (CCLDs), which are standardized cancer-specific databases established under the Korea-Clinical Data Utilization Network for Research Excellence (K-CURE) project by the Korean Ministry of Health and Welfare. Fifteen leading hospitals and fourteen academic associations in Korea are engaged in constructing CCLDs for 10 primary cancer types. For each cancer type-specific CCLD, cancer data experts determine key clinical data items essential for cancer research, standardize these items across cancer types, and create a standardized schema. Comprehensive clinical records covering diagnosis, treatment, and outcomes, with annual updates, are collected for each cancer patient in the target population, and quality control is based on six-sigma standards. To protect patient privacy, CCLDs follow stringent data security guidelines by pseudonymizing personal identification information and operating within a closed analysis environment. Researchers can apply for access to CCLD data through the K-CURE portal, which is subject to Institutional Review Board and Data Review Board approval. The CCLD is considered a pioneering standardized cancer-specific database, significantly representing Korea’s cancer data. It is expected to overcome limitations of previous CDMs and provide a valuable resource for multicenter cancer research in Korea.

Background/Aims: Direct-acting antivirals (DAAs) effectively eradicate hepatitis C virus. This study investigated whether metabolic dysfunction influences the likelihood of fibrosis regression after DAA treatment in patients with chronic hepatitis C (CHC). Methods: This multicenter, retrospective study included 8,819 patients diagnosed with CHC who were treated with DAAs and achieved a sustained virological response (SVR) between January 2014 and December 2022. Fibrosis regression was defined as a 20% reduction in noninvasive surrogates for liver fibrosis, such as liver stiffness (LS) measured by vibration-controlled transient elastography (VCTE) and the fibrosis-4 (FIB-4) score. Hypercholesterolemia (h-TC) was defined as >200 mg/dL. Results: The median age of the study population was 59.6 years, with a predominance of male patients (n=4,713, 57.3%). Genotypes 1, 2, and others were confirmed in 3,872 (46.2%), 3,487 (41.6%), and 1,024 (12.2%) patients, respectively. Diabetes mellitus (DM) was present in 1,442 (17.2%) patients and the median LS was 7.50 kPa (interquartile range, 5.30–12.50). Multivariate analysis revealed that the presence of DM and pre-DAA h-TC were independently associated with a decreased probability of fibrosis regression by VCTE. Additionally, pre-DAA h-TC was independently associated with a decreased probability of fibrosis regression by the FIB-4. Conclusions Metabolic dysfunction has an unfavorable influence on fibrosis regression in patients with CHC who achieve SVR after DAA treatment.

Background: Enchondroma is a common benign bone tumor in the hand, often leading to delayed diagnosis due to its asymptomatic nature. The surgical treatment strategy for enchondroma, particularly in pathologic fractures, remains unclear. This study aimed to evaluate the outcomes of treatment for non- or minimally displaced pathologic fractures in enchondroma using autogenous bone grafts alone, without metal fixation. Methods: A retrospective analysis was conducted on 34 patients who underwent surgery for enchondroma and pathologic fractures. Clinical and radiographic outcomes were assessed, including pain scores, range of motion (ROM), Disabilities of the Arm, Shoulder, and Hand (DASH) score, grip strength, fracture union time, and complications. Results: All patients reported pain at the fracture site preoperatively. The preoperative pain visual analog scale (VAS) score was 4.5.Postoperatively, the pain VAS score improved significantly to 2.3. The postoperative average total ROM was 253.8°. The average DASH score was 5.1, and grip strength was 97.8% compared to the unaffected side. Bony union was achieved in all cases with an average union time of 10.9 weeks. No complications were observed except for 1 suspected recurrence. Conclusions Early single-stage surgical treatment with curettage and autogenous bone grafts without fixation yielded satisfactory results for non- or minimally displaced pathologic fractures in enchondroma. This non-fixative technique offers a viable option with reduced treatment duration and implant-related complications.

Background: The management of distal radius fractures (DRFs) has evolved with the introduction of volar locking plate (VLP) fixation.Nevertheless, despite the low occurrence rates, reduction loss following VLP fixation has been reported in several studies. Our objective was to determine the incidence and features of reduction loss in patients despite the appropriate application of VLP fixation for DRF. Methods: This retrospective study was conducted between March 2017 and August 2023, during which a single hand surgeon performed VLP procedures for DRFs. This study included 379 patients (382 wrists) including 3 patients who underwent bilateral surgery. We identified patients who experienced reduction loss after VLP fixation (group 1) and patients without stability problems (group 2) and compared the 2 groups. Results: The mean age of the patients was 63.5 years, with a standard deviation of 13.8. There were 90 male patients (23.6%) and 289 female patients (75.7%). We identified 14 cases of DRFs, in which reduction loss occurred even after VLP fixation during the follow-up period (group 1, 3.7%). The remaining DRFs were assigned to group 2 (n=368, 96.3%). Among the 14 patients, 7 cases of screw breakage were identified as causing the loss of fracture reduction. As the joint surface collapsed and sank down to the distal row locking screw, 4 cases presented with distal locking screws penetrating into the radiocarpal joint. There were no significant differences between the 2 groups in terms of sex, weight, fracture arm direction, and Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) fracture classification. However, patients in group 1 were statistically significantly older than those in group 2 (average age, 77.5 years vs. 62 years). Among 4 patients experiencing distal screw violation of the radiocarpal joints, 3 underwent partial or complete screw removal immediately after fracture consolidation or union. Conclusions While rare, reduction loss remains a potential complication following VLP fixation, especially in elderly patients with intra-articular DRFs. However, with diligent monitoring and timely intervention, such as implant removal if necessary, acceptable outcomes can still be attained.

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) represents a devastating and growing global threat, calling for new antibiotic treatments. In Korea, the challenge of treating CRAB is compounded by high nosocomial acquisition rates and limited availability of novel antibiotics. Minocycline, a semisynthetic tetracycline derivative, has been proposed as a therapeutic option for CRAB infections. Nonsusceptibility to minocycline may occur through the efflux pump, TetB. The prevalence of tetB in A. baumannii has increased, along with higher minocycline minimum inhibitory concentrations (MICs). We aimed to evaluate minocycline susceptibility rates in clinical strains of CRAB, and the association between tetB carriage and minocycline susceptibility across different genotypes. Materials and Methods: Representative CRAB blood isolates were collected from Asan Medical Center, Seoul.Minocycline susceptibility was assessed using the Clinical and Laboratory Standards Institute (CLSI) breakpoint (≤4 mg/L) and the proposed pharmacokinetics (PK)/pharmacodynamics (PD) breakpoint (≤1 mg/L). Tigecycline was used as a comparator, and its susceptibility breakpoint for Enterobacterales defined by EUCAST was applied (≤0.5 mg/L).The presence of tetB was detected by PCR, and multilocus sequence typing (MLST) was performed using seven housekeeping genes. Results: Of the 160 CRAB blood isolates, 83.8% were susceptible to minocycline by the CLSI criteria, and 50.6% were PK-PD susceptible by the PK-PD criteria. The minocycline minimum inhibitory concentration (MIC)50 /MIC90 was 1/8 mg/L. tetB was present in 49% of isolates and was associated with a higher minocycline MIC (MIC50/90 2/8 mg/L vs. 1/2 mg/L). No clear correlation was observed between tetB positivity and tigecycline MIC. Nine MLSTs were identified, with significant differences in tetB carriage rates between the major sequence types. Notably, ST191, associated with non-tetB carriage and greater susceptibility to minocycline, declined over the study period (P=0.004), while ST451, associated with tetB carriage, increased. Conclusion tetB was present in 49% of CRAB isolates and was associated with higher MICs and non-susceptibility by both CLSI and PK-PD criteria. However, absence of tetB was not a reliable predictor of minocycline PK-PD susceptibility. Additionally, shifts over time towards genotypes with reduced minocycline susceptibility were observed. Further research is needed to correlate these findings with clinical outcomes and identify additional resistance mechanisms.

Purpose: The optimal reconstruction method following distal gastrectomy has not been elucidated. Since Billroth-II (B-II) reconstruction is commonly associated with increased bile reflux, Braun jejunojejunostomy has been proposed to reduce this complication. Materials and Methods: We retrospectively analyzed 325 patients with gastric cancer who underwent distal gastrectomy with B-II reconstruction between January 2015 and December 2017, comprising 159 patients without Braun anastomosis and 166 with Braun anastomosis.Outcomes were assessed over three years using annual gastroscopy based on the residual food, gastritis, and bile reflux criteria and the Los Angeles classification for reflux esophagitis. Results: In the first postoperative year, the group with Braun anastomosis showed a significant reduction in bile reflux compared to the group without Braun anastomosis (75.9% vs. 86.2%; P=0.019). Moreover, multivariate analysis identified Braun anastomosis as the sole factor associated with this outcome. Additionally, the group with Braun anastomosis had a lower incidence of heartburn (12.0% vs. 20.1%; P=0.047) and reduced use of prokinetics (P<0.001) and acid reducers (P=0.002) compared to the group without Braun anastomosis.However, these benefits diminished in subsequent years, with no significant differences in residual food, gastritis, or reflux esophagitis between the groups. Both groups showed similar body mass index scores and nutritional outcomes over the 3-year follow-up period. Conclusions Although Braun anastomosis offers short-term benefits in reducing bile reflux after B-II reconstruction, these effects are not sustainable. The routine use of Braun anastomosis should be reconsidered, though either approach remains a viable option depending on the patient’s circumstances.

Background: This study aimed to identify key priorities for the development of guidelines for information and communication technology (ICT)-based patient education tailored to the needs of patients with rheumatic diseases (RDs) in the Republic of Korea, based on expert consensus. Methods: A two-round modified Delphi study was conducted with 20 rheumatology, patient education, and digital health literacy experts. A total of 35 items covering 7 domains and 18 subdomains were evaluated. Each item was evaluated for its level of importance, and the responses were rated on a 4-point Likert scale. Consensus levels were defined as “high” (interquartile range [IQR] ≤ 1, agreement ≥ 80%, content validity ratio [CVR] ≥ 0.7), "Moderate" (IQR ≥ 1, agreement 50–79%, CVR 0.5–0.7), and "Low" (IQR > 1, agreement < 50%, CVR < 0.5). Results: Strong consensus was reached for key priorities for developing guidelines in areas such as health literacy, digital health literacy, medical terminology, user interface, and user experience design for mobile apps. Chatbot use and video (e.g., YouTube) also achieved high consensus, whereas AI-powered platforms such as ChatGPT showed moderate-to-high agreement. Telemedicine was excluded because of insufficient consensus. Conclusion The key priorities identified in this study provide a foundation for the development of ICT-based patient education guidelines for RDs in the Republic of Korea.Future efforts should focus on integrating digital tools into clinical practice to enhance patient engagement and improve clinical outcomes.