1.Stress Accelerates Depressive-Like Behaviors through Increase of Notch2 Expression in N141I Mutation Presenilin-2 Transgenic Mice
Seung Sik YOO ; Sun Mi GU ; Kyung Tak NAM ; Jeong Soon CHOI ; Yong Sun LEE ; In Jun YEO ; Ji Eun YU ; Sanghyeon KIM ; Dong Won LEE ; Hyeon Joo HAM ; Ju Young CHANG ; Jaesuk YUN ; Dong Ju SON ; Sang-Bae HAN ; Jin Tae HONG
Biomolecules & Therapeutics 2026;34(3):544-555
Alzheimer’s disease (AD) is characterized by progressive cognitive deterioration and significant depression. However, the mechanisms linking depression to AD pathology remain unclear. Here, we investigated whether Notch2 signaling mediates depressionlike behaviors in presenilin-2 (PS2) N141I mutant mice, an early-onset AD model. PS2 wild-type (WT) and mutant (MT) mice aged 12-15 months were subjected to unpredictable chronic mild stress (UCMS) for 4 weeks, followed by sucrose preference, tail-hanging, and forced swimming tests. Behavioral assessments showed that UCMS exacerbated anhedonia and immobility only in PS2 MT mice. Molecular analysis revealed concomitant increases in plasma corticosterone, hippocampal γ-secretase activity, and Notch2 expression, and elevated total and phosphorylated glucocorticoid receptor levels in PS2 MT-UCMS mice. Gene expression profiling of human hippocampal datasets confirmed upregulation of NOTCH2 in Alzheimer’s disease and depression.Pharmacological inhibition of γ-secretase and Notch signaling with DAPT normalizes depressive behavior, reduces corticosterone release, attenuates GR phosphorylation, and inhibits Notch2 signaling in PS2 MT mice. These findings identify Notch2 as a pivotal mediator linking chronic stress to molecular changes associated with depression and AD, and suggest that targeting Notch2 signaling may provide therapeutic benefits for comorbid mood and neurodegenerative disorders.
2.Molecular Mosaics: Unveiling Heterogeneity in Synchronous Colorectal Cancers
Hyun Gu LEE ; Yeseul KIM ; Mi-Ju KIM ; Yeon Wook KIM ; Sun-Young JUN ; Deokhoon KIM ; In Ja PARK ; Seung-Mo HONG
Cancer Research and Treatment 2026;58(1):264-274
Purpose:
Molecular characteristics of synchronous colorectal cancers (SCRCs) remain incompletely elucidated, despite their importance in targeted therapy selection. We compared the molecular characteristics and somatic mutations between SCRCs.
Materials and Methods:
This retrospective study (2012-2014) included 98 consecutive patients with surgically resected SCRCs. Molecular characteristics, including microsatellite instability (MSI) and tumor-infiltrating lymphocytes (TILs), were analyzed for all cancer lesions. The intertumoral heterogeneity of SCRCs was evaluated using whole-exome sequencing (WES) for 18 cancers from nine patients with at least one MSI-high (MSI-H) tumor.
Results:
Twelve patients had at least one MSI-H tumor; five showed discordant MSI status. Mucinous adenocarcinoma frequency and TIL density were higher in patients with at least one MSI-H tumor than in those with only microsatellite-stable tumors. WES revealed that, except one patient (6.5%), most synchronous cancers shared few variants in each patient (0.09%-0.36%). The concordance rates for BRAF, KRAS, NRAS, and PIK3CA, in synchronous cancers from each patient were 66.7%, 66.7%, 66.7%, and 55.6%, respectively.
Conclusion
Although synchronous cancers shared a mutated gene, the mutation subtypes differed. SCRCs exhibited 5.1% MSI status discordance rate and a high discordance rate in somatic mutational variants. As intertumoral heterogeneity may affect the targeted therapy response, molecular analysis of all tumors is recommended for patients with SCRCs.
3.Outcomes of Lung Transplantation for Bronchiolitis Obliterans after Hematopoietic Stem Cell Transplantation Compared with Those for Idiopathic Pulmonary Fibrosis
Bong Suk PARK ; Ha Eun KIM ; Young Ho YANG ; Dae Joon KIM ; Chang Young LEE ; Byung Jo PARK ; A La WOO ; Eun Young KIM ; Moo Suk PARK ; Song Yee KIM ; Jin Gu LEE
Yonsei Medical Journal 2026;67(1):27-33
Purpose:
Bronchiolitis obliterans syndrome (BOS) can develop as a manifestation of graft-versus-host disease following allogeneic hematopoietic stem cell transplantation (allo-HSCT), and may ultimately require lung transplantation (LT). However, reports on LT outcomes for BOS after allo-HSCT are limited. This study aimed to compare the outcomes of LT for BOS following allo-HSCT with those for idiopathic pulmonary fibrosis (IPF).
Materials and Methods:
A total of 487 patients underwent LT between January 2010 and August 2023. Among them, the baseline characteristics and outcomes of 35 patients with BOS following allo-HSCT and 216 patients with IPF were analyzed.
Results:
The BOS group was younger and had a lower body mass index (BMI) compared to the IPF group (33.7±11.9 years vs.59.7±7.3 years, p<0.001; 17.6±3.7 kg/m2 vs. 22.0±3.6 kg/m2 , p<0.001, respectively). The proportion of male patients was lower in the BOS group than in the IPF group (54.3% vs. 84.3%, p<0.001). Preoperative ventilator support was more common in the BOS group compared to the IPF group (62.9% vs. 32.4%, p=0.001). In Kaplan–Meier survival analysis, the 5-year survival rate was significantly higher in the BOS group than in the IPF group (71.0% vs. 44.9%, p=0.022). In the Cox proportional hazards model, age was the only factor significantly associated with survival [hazard ratio (95% confidence interval): 1.04 (1.02–1.07), p<0.001].
Conclusion
The survival rate of the BOS group was not inferior to that of the IPF group after adjusting for sex, age, and BMI. Therefore, LT should be actively considered as a treatment option for patients with BOS following allo-HSCT.
4.Establishing an Active Vaccine Safety Surveillance System Using Large Scale Databases in Korea: Lessons and Scalable Insights for Global Application
Jin Gu YOON ; Eliel NHAM ; Yu Jung CHOI ; Min Joo CHOI ; Won Suk CHOI ; Young Kyung YOON ; Yu Bin SEO ; Hakjun HYUN ; Jung Yeon HEO ; Jin-Soo LEE ; Chung-Jong KIM ; Ji Yun NOH ; Joon Young SONG ; Hee Jin CHEONG
Journal of Korean Medical Science 2026;41(1):e47-
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.
5.Two Clinical Cases of Compulsive Sexual Behavior and Illegal Voyeurism: Report and Discussion
Seon Young PARK ; Ung Gu KANG ; Jaehyun KIM ; Myung Je SUNG
Journal of Korean Neuropsychiatric Association 2026;65(1):50-57
This paper reports two clinical cases of men in their twenties who presented with compulsive sexual behaviors characterized by excessive pornography use and illegal voyeuristic activities. Although both individuals maintained otherwise adequate social and academic functioning, they experienced psychological distress and faced legal consequences stemming from their inability to control their sexual impulses. Pharmacological treatment with naltrexone and fluoxetine was associated with a reduction in their compulsive urges. Compulsive sexual behavior disorder (CSBD) has not yet been formally included in the Diagnostic and Statistical Manual of Mental Disorders (DSM), and its status as a potential behavioral addiction remains under debate. Voyeuristic behavior is classified within paraphilic disorders, which are considered diagnostically separate from CSBD despite substantial clinical overlap. These cases contribute to the ongoing discussions regarding the conceptualization of CSBD and highlight the importance of recognizing and expanding the therapeutic approaches for individuals struggling with impaired sexual impulse control.
6.Comparative Effects of Isometric Exercise Types on 24-Hour Ambulatory Blood Pressure in Young Men with Prehypertension: An Acute Pilot Trial
Seung Won JUNG ; Hyun Soo SONG ; Sun Jung KIM ; Ho Jeong MIN ; Tae Gu CHOI ; Hyun Jeong KIM ; Sae Young JAE
The Korean Journal of Sports Medicine 2026;44(1):25-33
Purpose:
This study aimed to compare the acute effects of isometric handgrip (IHG) and wall squat (IWS) exercise on 24-hour ambulatory blood pressure (BP) and related indices in young men with prehypertension.
Methods:
Ten young men with prehypertension (aged 25.0±2.3 years) completed three randomized crossover conditions: IHG, IWS, and control. Twenty-four-hour ambulatory BP monitoring was used to assess 24-hour, daytime, and nighttime mean BP, BP variability (BPV; average real variability and standard deviation), morning BP, and nocturnal dipping pattern. Office BP was measured at baseline, 30 minutes, and 90 minutes after each condition.
Results:
Twenty-four hour, daytime, and nighttime systolic and diastolic BP did not differ significantly among conditions. BPV indices also showed no significant between-condition differences across 24-hour, daytime, or nighttime periods. Nocturnal systolic BP dipping averaged 5%–8% and did not differ among conditions, indicating a nondipper pattern in all trials. Morning systolic BP, sleep-trough surge, and prewaking surge were similar across conditions. Office BP showed no significant condition or interaction effects; however, both IHG and IWS tended to lower BP at 90 minutes compared with control session.
Conclusion
A single bout of IHG or IWS did not elicit significant changes in 24-hour ambulatory BP, BPV, morning BP, or dipping pattern in young men with prehypertension. Nonetheless, the small acute reductions in office and morning BP suggest that isometric exercise may have potential as a time-efficient adjunctive strategy for early BP management. Larger and longer-term studies are needed to confirm these findings.
7.Acute Effects of Inspiratory Muscle Strength Exercise on Vascular Function and Shear Pattern in Young Adults
Tae Gu CHOI ; Hyun Soo SONG ; Sun Jung KIM ; Seung Won JUNG ; Byul KIM ; Hyun Jeong KIM ; Sae Young JAE
The Korean Journal of Sports Medicine 2026;44(1):16-24
Purpose:
Inspiratory muscle strength training is a time-efficient strategy for lowering blood pressure, but the acute vascular effects and its hemodynamic characteristics remain unclear. This study aimed to determine the acute effects of inspiratory muscle strength exercise (IMSE) on vascular function and shear patterns.
Methods:
In a single-arm acute trial, 12 young adults (aged 26±2 years) performed a single bout of IMSE (about 8 minutes) consisting of 30 breaths (6 breaths×5 sets) at 60% of maximal inspiratory pressure. Vascular function indices were assessed as endothelial function and arterial stiffness. Measurements of endothelial function via flow-mediated dilation (FMD) in the brachial artery and arterial stiffness by carotid-femoral pulse wave velocity (cfPWV) were taken at baseline, 10 minutes, and 40 minutes post-IMSE. Shear rate (SR) responses were continuously obtained throughout the IMSE session at the brachial artery and were analyzed as mean SR, anterograde SR, and retrograde SR.
Results:
Compared to baseline, cfPWV significantly decreased (7.95±0.9 m/sec to 7.49±0.9 m/sec, p=0.033) and FMD increased (4.76%±1.0% to 6.26%±1.1%, p< 0.001) at post-10 min. Both cfPWV and FMD returned to baseline levels at post-40 min. During IMSE, mean SR and anterograde SR significantly increased (both, p< 0.05), whereas retrograde SR decreased (p=0.032) during inter-set rest periods. In addition, rhythmic fluctuations in SR were observed corresponding to inspiration and expiration phases.
Conclusion
These findings suggest that an acute bout of IMSE is associated with improved endothelial function and arterial stiffness. IMSE may elicit distinct hemodynamic responses during exercise, which may be linked to improvements in vascular function.
8.Effects of Combined Exercise Training on Symptoms and Physical Fitness in Young Adults with Mild Long COVID
Tae Gu CHOI ; Jae Yeop KIM ; Ho Jeong MIN ; Hyun Jeong KIM ; Kanokwan BUNSAWAT ; Setor K KUNUTSOR ; Kevin S HEFFERNAN ; Sae Young JAE
The Korean Journal of Sports Medicine 2025;43(1):1-12
Purpose:
The aim of this study was to examine whether a combined exercise (EX), including aerobic, resistance, and inspiratory muscle training, reduces fatigue and dyspnea, improves physical fitness, and if increased physical fitness after exercise is associated with attenuating symptoms in young adults with mild long coronavirus disease (COVID) symptoms.
Methods:
Twenty-eight young adults (aged 23±4 years) with long COVID were randomly assigned to either the EX group (n=14), which underwent aerobic, resistance, and inspiratory muscle training three times per week for 8 weeks, or the control (CON) group (n=14). Symptoms of dyspnea and fatigue were assessed using self-report questionnaires.Cardiorespiratory fitness was directly measured during cardiopulmonary exercise testing, while muscle strength was measured by isokinetic muscle testing. These variables were measured before and after the exercise intervention.
Results:
Compared to the CON group, the EX group showed improvements in symptoms of fatigue and dyspnea, maximal oxygen consumption (VO2peak ), and peak torque, with significant interaction effects observed (p< 0.05). The EX group exhibited a mean difference of 2.9 mL/kg/min in VO2peak (95% confidence interval [CI], 1.8−4.0) and 13.0 Nm (95% CI, 6.1−19.8) in peak torque compared to the CON group (p<0.05). Improvements in VO2peak were negatively associated with attenuations in both fatigue and dyspnea after the exercise intervention (p<0.05).
Conclusion
These findings indicate that EX training can effectively alleviate symptoms and improve physical fitness in young adults with mild long COVID. Structured exercise training may serve as an effective intervention to improve the health of those with long COVID.
9.Reducing Healing Period with DDM/rhBMP-2 Grafting for Early Loading in Dental Implant Surgery
Jeong-Kui KU ; Jung-Hoon LIM ; Jung-Ah LIM ; In-Woong UM ; Yu-Mi KIM ; Pil-Young YUN
Tissue Engineering and Regenerative Medicine 2025;22(2):261-271
Background:
Traditionally, dental implants require a healing period of 4 to 9 months for osseointegration, with longer recovery times considered when bone grafting is needed. This retrospective study evaluates the clinical efficacy of demineralized dentin matrix (DDM) combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) during dental implant placement to expedite the osseointegration period for early loading.
Methods:
Thirty patients (17 male, 13 female; mean age 55.0 ± 8.8 years) requiring bone grafts due to implant fixture exposure (more than four threads; ≥ 3.2 mm) were included, with a total of 96 implants placed. Implants were inserted using a two-stage protocol with DDM/rhBMP-2 grafts. Early loading was initiated at two months postoperatively in the mandible and three months in the maxilla. Clinical outcomes evaluated included primary and secondary stability (implant stability quotient values), healing period, bone width, and marginal bone level assessed via cone-beam computed tomography.
Results:
All implants successfully supported final prosthetics with a torque of 50Ncm, without any osseointegration failures. The average healing period was 69.6 days in the mandible and 90.5 days in the maxilla, with significantly higher secondary stability in the mandible (80.7 ± 6.7) compared to the maxilla (73.0 ± 9.2, p < 0.001). Histological analysis confirmed new bone formation and vascularization.
Conclusion
DDM/rhBMP-2 grafting appears to significantly reduce the healing period, enabling early loading with stable and favorable clinical outcomes.
10.Regenerative Capacity of Alveolar Type 2 Cells Is Proportionally Reduced Following Disease Progression in Idiopathic Pulmonary Fibrosis-Derived Organoid Cultures
Hyeon Kyu CHOI ; Gaeul BANG ; Ju Hye SHIN ; Mi Hwa SHIN ; Ala WOO ; Song Yee KIM ; Sang Hoon LEE ; Eun Young KIM ; Hyo Sup SHIM ; Young Joo SUH ; Ha Eun KIM ; Jin Gu LEE ; Jinwook CHOI ; Ju Hyeon LEE ; Chul Hoon KIM ; Moo Suk PARK
Tuberculosis and Respiratory Diseases 2025;88(1):130-137
Background:
Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disease that culminates in respiratory failure and death due to irreversible scarring of the distal lung. While initially considered a chronic inflammatory disorder, the aberrant function of the alveolar epithelium is now acknowledged as playing a central role in the pathophysiology of IPF. This study aimed to investigate the regenerative capacity of alveolar type 2 (AT2) cells using IPF-derived alveolar organoids and to examine the effects of disease progression on this capacity.
Methods:
Lung tissues from three pneumothorax patients and six IPF patients (early and advanced stages) were obtained through video-assisted thoracoscopic surgery and lung transplantation. HTII-280+ cells were isolated from CD31-CD45-epithelial cell adhesion molecule (EpCAM)+ cells in the distal lungs of IPF and pneumothorax patients using fluorescence-activated cell sorting (FACS) and resuspended in 48-well plates to establish IPF-derived alveolar organoids. Immunostaining was used to verify the presence of AT2 cells.
Results:
FACS sorting yielded approximately 1% of AT2 cells in early IPF tissue, and the number decreased as the disease progressed, in contrast to 2.7% in pneumothorax. Additionally, the cultured organoids in the IPF groups were smaller and less numerous compared to those from pneumothorax patients. The colony forming efficiency decreased as the disease advanced. Immunostaining results showed that the IPF organoids expressed less surfactant protein C (SFTPC) compared to the pneumothorax group and contained keratin 5+ (KRT5+) cells.
Conclusion
This study confirmed that the regenerative capacity of AT2 cells in IPF decreases as the disease progresses, with IPF-derived AT2 cells inherently exhibiting functional abnormalities and altered differentiation plasticity.

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