1.Exosomes from Human Embryonic Stem Cell-Derived Mesenchymal Stem Cells Protect Lung Epithelium and Attenuate Fibrosis
Sangryul CHA ; Jooyeon LEE ; Jimin JANG ; Yeongcheol KIM ; Dahee HAN ; Seok-Ho HONG ; Seung-Jin KIM ; Dae-Hee LEE ; Chung Hyeun MA ; Han Pil LEE ; Se-Ran YANG
International Journal of Stem Cells 2026;19(1):66-82
Idiopathic pulmonary fibrosis (IPF) is characterized by maladaptive epithelial–mesenchymal crosstalk and progressive extracellular matrix accumulation, whereas currently available antifibrotic agents merely decelerate functional decline.This study investigated whether exosomes derived from human mesenchymal stem cells derived from embryonic stem cells (ESC-MSCs) restore epithelial stress responses and attenuate fibrotic remodeling. Human IPF lung transcriptomes were integrated with a bleomycin-induced murine model analyzed by RNA sequencing and protein signaling, together with cigarette smoke extract-induced injury in A549 epithelial cells. ESC-MSCs-derived exosomes exhibited typical morphology and size distribution, enrichment of tetraspanins, and absence of endoplasmic reticulum contamination, consistent with high-purity preparations. Across human IPF and bleomycin-injured lungs, transcriptomic profiling revealed prominent enrichment of extracellular matrix and cytoskeletal gene programs, whereas mitogen-activated protein kinase (MAPK) and Smad families displayed only modest alterations at the mRNA level. In vivo administration of exosomes during the fibrotic remodeling phase, via either intravenous or intratracheal delivery, resulted in improved body weight, reduced lung weight-to-body weight ratios, and decreased collagen deposition and Ashcroft scores. These structural and functional improvements were accompanied by suppression of profibrotic and mesenchymal markers and selective attenuation of activator protein-1 (AP-1) activity. In epithelial injury models, ESC-MSCs-derived exosomes enhanced cell viability, restored redox homeostasis, and constrained stress-induced mesenchymal gene expression and MAPK phosphorylation in both co-treatment and post-treatment settings. Collectively, these data support an epithelial-centered mechanism in which ESC-MSCs-derived exosomes re-establish oxidative balance and selectively restrict AP-1-driven stress signaling, thereby secondarily limiting extracellular matrix accumulation and fibrotic remodeling.
2.Angiogram Negative Subarachnoid Hemorrhage Revealed as Midbasilar Perforator Pseudoaneurysm Rupture on Delayed Angiography
Joon Hyeoung KIM ; Jun Soo BYUN ; Min Ho KONG ; Se Youn JANG ; Jung Hee KIM ; Sunghoon KIM
Journal of Neurointensive Care 2025;8(2):62-66
Angiogram-negative subarachnoid hemorrhage (SAH) represents a diagnostic challenge because rebleeding risk persists despite negative initial angiography. We report a rare case of a 65-year-old man presenting with diffuse SAH on initial CT but with negative CTA and transfemoral cerebral angiography (TFCA). Serial follow-up CT scans demonstrated gradual resolution of subarachnoid blood except for persistent prepontine cisternal hemorrhage. On hospital day 7, repeat TFCA revealed a bilobulated pseudoaneurysm arising from a midbasilar perforator artery. The lesion was treated using a modified stent-assisted coiling technique involving partial coil deployment, achieving complete angiographic obliteration with parent artery preservation. Post-procedural diffusion-weighted MRI demonstrated a left pontine infarction, but the patient achieved meaningful functional recovery and returned to work at the 3-month follow-up. This case underscores the necessity of repeat angiography in diffuse angiogram-negative SAH and highlights tailored endovascular strategies for fragile basilar perforator pseudoaneurysm.
3.Concomitant Pulmonary and Cranial Abscesses Caused by Streptococcus Gordonii
Jeong-Woo HA ; Kwan-Young SONG ; Min-Ho KONG ; Se-Youn JANG ; Jung-Hee KIM ; Sung-Hoon KIM ; Soon-O HONG
Journal of Neurointensive Care 2025;8(2):57-61
Streptococcus gordonii is an oral commensal viridans streptococcus that rarely causes invasive infections such as lung abscess or intracranial empyema. The sequential presentation of concomitant pulmonary and cranial abscesses by this organism is extremely uncommon. A 70-year-old man presented with progressive dyspnea and fever. Chest CT demonstrated a 14.4 × 6.8cm mass like lung lesion consistent with a lung abscess. Percutaneous drainage yielded Streptococcus gordoniii. On hospital day 5 following drainage, patient presented with scalp swelling and headache. Brain MRI revealed a subgaleal abscess with an epidural empyema. Emergent craniectomy and debridement were performed, and cultures again grew Streptococcus gordonii. This case is a rare but clinically significant pattern of sequential presentation of concomitant pulmonary and cranial abscesses caused by Streptococcus gordonii, emphasizing the need for dental evaluation, meticulous inpatient monitoring, and early neuroimaging when viridans streptococci are revealed from deep infections.
4.Digital Psychiatry with Chatbot: Recent Advances and Limitations
Se Chang YOON ; Ji Hyun AN ; Jung-Seok CHOI ; June Ho CHANG ; Yoo Jin JANG ; Hong Jin JEON
Clinical Psychopharmacology and Neuroscience 2025;23(4):542-550
Objective:
The escalating global mental health crisis necessitates innovative solutions to address traditional service limitations such as high costs and professional shortages. This review examines the emerging role of artificial intelligence (AI) chatbots in digital psychiatry, analyzing their clinical efficacy, ethical challenges, and future directions.
Methods:
This narrative review synthesizes evidence from recent randomized controlled trials, meta-analyses, and scholarly publications on AI chatbots for mental health. It also discusses the ethical and social implications, including data privacy, algorithmic bias, and cognitive effects, and provides a forward-looking roadmap for regulation and development.
Results:
Chatbots grounded in evidence-based principles like cognitive-behavioral therapy demonstrate clinical effectiveness in reducing symptoms of depression and anxiety, with some studies reporting a strong “therapeutic alliance” comparable to that with human therapists. AI models also show promise in diagnostic and predictive roles by analyzing selfreport questionnaires and physiological data. However, critical risks include inappropriate responses in crisis situations, potential for AI psychosis, and the erosion of cognitive abilities due to over-reliance.
Conclusion
The future of digital psychiatry lies in a blended care model that combines the accessibility of AI with the indispensable empathy and professional judgment of human clinicians. A collaborative roadmap is essential, mandating safety protocols, strengthened data governance, expert involvement, and ethical design to ensure AI acts as a transformative and responsible tool.
5.Comparison of Clinicopathogenomic Features and Treatment Outcomes of EGFR and HER2 Exon 20 Insertion Mutations in Non–Small Cell Lung Cancer: Single-Institution Experience
So Heun LEE ; Hyehyun JEONG ; Deok Hoon KIM ; Se Jin JANG ; Sang-We KIM ; Shinkyo YOON ; Dae Ho LEE
Cancer Research and Treatment 2024;56(3):774-784
Purpose:
Exon 20 insertion mutations (E20ins) in epidermal growth factor receptor (EGFR) or human epidermal growth factor receptor 2 (HER2) in non–small cell lung cancer (NSCLC) patients has become more important with emergence of novel agents targeting E20ins.
Materials and Methods:
Advanced/Metastatic NSCLC patients with E20ins were included. EGFR E20ins was identified by two methods, next-generation sequencing (NGS) or real-time polymerase chain reaction (PCR), while HER2 E20ins was done by NGS only.
Results:
Between December 2013 and July 2021, E20ins were identified in 107 patients at Asan Medical Center; 67 EGFR E20ins and 40 HER2 E20ins. Out of 32 patients with EGFR E20ins who had tested both PCR and NGS, 17 were identified only through NGS and the other 15 through both tests, giving a discordance rate of 53.1%. There was no clinically significant difference in clinicopathologic features between EGFR and HER2 E20ins; both were observed more frequently in adenocarcinoma, female and never-smokers. Brain metastases were evident at diagnosis in 31.8% of EGFR E20ins and 27.5% of HER2 E20ins, respectively. Platinum-based doublets demonstrated objective response rates (ORR) of 13.3% with a median progression-free survival (PFS) of 4.2 months for EGFR E20ins and 35.3% with 4.7 months for HER2 E20ins, respectively. In contrast, novel EGFR E20ins-targeted agents exhibited an ORR of 46.2% with a median PFS of 5.4 months, while HER2-targeted agents showed an ORR of 50% with that of 7.0 months.
Conclusion
Identification of EGFR and HER2 E20ins is more important as their targeted therapies improved outcomes. Upfront NGS test as a comprehensive molecular approach is strongly warranted.
6.Ventral Anterior Cingulate Atrophy as a Predisposing Factor for Transient Global Amnesia
Jeewon SUH ; Young Ho PARK ; Hang-Rai KIM ; Jae-Won JANG ; SangHak YI ; Min Ju KANG ; Yun Jung BAE ; Byung Se CHOI ; Jae Hyoung KIM ; SangYun KIM
Dementia and Neurocognitive Disorders 2024;23(2):89-94
Background:
and Purpose: This study aimed to evaluate the brain magnetic resonance imaging (MRI) of patients with acute transient global amnesia (TGA) using volumetric analysis to verify whether the brains of TGA patients have pre-existing structural abnormalities.
Methods:
We evaluated the brain MRI data from 87 TGA patients and 20 age- and sexmatched control subjects. We included brain MRIs obtained from TGA patients within 72 hours of symptom onset to verify the pre-existence of structural change. For voxel-based morphometric analyses, statistical parametric mapping was employed to analyze the structural differences between patients with TGA and control subjects.
Results:
TGA patients exhibited significant volume reductions in the bilateral ventral anterior cingulate cortices (corrected p<0.05).
Conclusions
TGA patients might have pre-existing structural changes in bilateral ventral anterior cingulate cortices prior to TGA attacks.
7.Immune Cells Are DifferentiallyAffected by SARS-CoV-2 Viral Loads in K18-hACE2 Mice
Jung Ah KIM ; Sung-Hee KIM ; Jeong Jin KIM ; Hyuna NOH ; Su-bin LEE ; Haengdueng JEONG ; Jiseon KIM ; Donghun JEON ; Jung Seon SEO ; Dain ON ; Suhyeon YOON ; Sang Gyu LEE ; Youn Woo LEE ; Hui Jeong JANG ; In Ho PARK ; Jooyeon OH ; Sang-Hyuk SEOK ; Yu Jin LEE ; Seung-Min HONG ; Se-Hee AN ; Joon-Yong BAE ; Jung-ah CHOI ; Seo Yeon KIM ; Young Been KIM ; Ji-Yeon HWANG ; Hyo-Jung LEE ; Hong Bin KIM ; Dae Gwin JEONG ; Daesub SONG ; Manki SONG ; Man-Seong PARK ; Kang-Seuk CHOI ; Jun Won PARK ; Jun-Won YUN ; Jeon-Soo SHIN ; Ho-Young LEE ; Ho-Keun KWON ; Jun-Young SEO ; Ki Taek NAM ; Heon Yung GEE ; Je Kyung SEONG
Immune Network 2024;24(2):e7-
Viral load and the duration of viral shedding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are important determinants of the transmission of coronavirus disease 2019.In this study, we examined the effects of viral doses on the lung and spleen of K18-hACE2 transgenic mice by temporal histological and transcriptional analyses. Approximately, 1×105 plaque-forming units (PFU) of SARS-CoV-2 induced strong host responses in the lungs from 2 days post inoculation (dpi) which did not recover until the mice died, whereas responses to the virus were obvious at 5 days, recovering to the basal state by 14 dpi at 1×102 PFU. Further, flow cytometry showed that number of CD8+ T cells continuously increased in 1×102 PFU-virusinfected lungs from 2 dpi, but not in 1×105 PFU-virus-infected lungs. In spleens, responses to the virus were prominent from 2 dpi, and number of B cells was significantly decreased at 1×105PFU; however, 1×102 PFU of virus induced very weak responses from 2 dpi which recovered by 10 dpi. Although the defense responses returned to normal and the mice survived, lung histology showed evidence of fibrosis, suggesting sequelae of SARS-CoV-2 infection. Our findings indicate that specific effectors of the immune response in the lung and spleen were either increased or depleted in response to doses of SARS-CoV-2. This study demonstrated that the response of local and systemic immune effectors to a viral infection varies with viral dose, which either exacerbates the severity of the infection or accelerates its elimination.
8.Diagnostic Utility of Whole Genome Sequencing After Negative Karyotyping/Chromosomal Microarray in Infants Born With Multiple Congenital Anomalies
Misun YANG ; Jee Ah KIM ; Heui Seung JO ; Jong-Ho PARK ; So Yoon AHN ; Se In SUNG ; Won Soon PARK ; Hye-Won CHO ; Jeong-Min KIM ; Mi-Hyun PARK ; Hyun-Young PARK ; Ja-Hyun JANG ; Yun Sil CHANG
Journal of Korean Medical Science 2024;39(36):e250-
Background:
Achieving a definitive genetic diagnosis of unexplained multiple congenital anomalies (MCAs) in neonatal intensive care units (NICUs) infants is challenging because of the limited diagnostic capabilities of conventional genetic tests. Although the implementation of whole genome sequencing (WGS) has commenced for diagnosing MCAs, due to constraints in resources and faculty, many NICUs continue to utilize chromosomal microarray (CMA) and/or karyotyping as the initial diagnostic approach. We aimed to evaluate the diagnostic efficacy of WGS in infants with MCAs who have received negative results from karyotyping and/or CMA.
Methods:
In this prospective study, we enrolled 80 infants with MCAs who were admitted to a NICU at a single center and had received negative results from CMA and/or karyotyping.The phenotypic characteristics were classified according to the International Classification of Diseases and the Human Phenotype Ontology. We assessed the diagnostic yield of trioWGS in infants with normal chromosomal result and explored the process of diagnosing by analyzing both phenotype and genotype. Also, we compared the phenotype and clinical outcomes between the groups diagnosed with WGS and the undiagnosed group. Results: The diagnostic yield of WGS was 26% (21/80), of which 76% were novel variants.There was a higher diagnostic yield in cases of craniofacial abnormalities, including those of the eye and ear, and a lower diagnostic yield in cases of gastrointestinal and genitourinary abnormalities. In addition, higher rates of rehabilitation therapy and gastrostomy were observed in WGS-diagnosed infants than in undiagnosed infants.
Conclusion
This prospective cohort study assessed the usefulness of trio-WGS following chromosomal analysis for diagnosing MCAs in the NICU and revealed improvements in the diagnostic yield and clinical utility of WGS.
9.Recombinant Human Bone Morphogenetic Protein-2 Priming of Mesenchymal Stem Cells Ameliorate Acute Lung Injury by Inducing Regulatory T Cells
Jooyeon LEE ; Jimin JANG ; Sang-Ryul CHA ; Se Bi LEE ; Seok-Ho HONG ; Han-Sol BAE ; Young Jin LEE ; Se-Ran YANG
Immune Network 2023;23(6):e48-
Mesenchymal stromal/stem cells (MSCs) possess immunoregulatory properties and their regulatory functions represent a potential therapy for acute lung injury (ALI). However, uncertainties remain with respect to defining MSCs-derived immunomodulatory pathways.Therefore, this study aimed to investigate the mechanism underlying the enhanced effect of human recombinant bone morphogenic protein-2 (rhBMP-2) primed ES-MSCs (MSC BMP2 ) in promoting Tregs in ALI mice. MSC were preconditioned with 100 ng/ml rhBMP-2 for 24 h, and then administrated to mice by intravenous injection after intratracheal injection of 1 mg/kg LPS. Treating MSCs with rhBMP-2 significantly increased cellular proliferation and migration, and cytokines array reveled that cytokines release by MSC BMP2 were associated with migration and growth. MSC BMP2 ameliorated LPS induced lung injury and reduced myeloperoxidase activity and permeability in mice exposed to LPS. Levels of inducible nitric oxide synthase were decreased while levels of total glutathione and superoxide dismutase activity were further increased via inhibition of phosphorylated STAT1 in ALI mice treated with MSC BMP2 . MSC BMP2 treatment increased the protein level of IDO1, indicating an increase in Treg cells, and Foxp3 + CD25 + Treg of CD4 + cells were further increased in ALI mice treated with MSC BMP2 . In co-culture assays with MSCs and RAW264.7 cells, the protein level of IDO1 was further induced in MSC BMP2 . Additionally, cytokine release of IL-10 was enhanced while both IL-6 and TNF-α were further inhibited. In conclusion, these findings suggest that MSC BMP2 has therapeutic potential to reduce massive inflammation of respiratory diseases by promoting Treg cells.
10.TNM-Based Head-to-Head Comparison of Urachal Carcinoma and Urothelial Bladder Cancer: Stage-Matched Analysis of a Large Multicenter National Cohort
Sang Hun SONG ; Jaewon LEE ; Young Hwii KO ; Jong Wook KIM ; Seung Il JUNG ; Seok Ho KANG ; Jinsung PARK ; Ho Kyung SEO ; Hyung Joon KIM ; Byong Chang JEONG ; Tae-Hwan KIM ; Se Young CHOI ; Jong Kil NAM ; Ja Yoon KU ; Kwan Joong JOO ; Won Sik JANG ; Young Eun YOON ; Seok Joong YUN ; Sung-Hoo HONG ; Jong Jin OH
Cancer Research and Treatment 2023;55(4):1337-1345
Purpose:
Outcome analysis of urachal cancer (UraC) is limited due to the scarcity of cases and different staging methods compared to urothelial bladder cancer (UroBC). We attempted to assess survival outcomes of UraC and compare to UroBC after stage-matched analyses.
Materials and Methods:
Total 203 UraC patients from a multicenter database and 373 UroBC patients in single institution from 2000 to 2018 were enrolled (median follow-up, 32 months). Sheldon stage conversion to corresponding TNM staging for UraC was conducted for head-to-head comparison to UroBC. Perioperative clinical variables and pathological results were recorded. Stage-matched analyses for survival by stage were conducted.
Results:
UraC patients were younger (mean age, 54 vs. 67 years; p < 0.001), with 163 patients (80.3%) receiving partial cystectomy and 23 patients (11.3%) radical cystectomy. UraC was more likely to harbor ≥ pT3a tumors (78.8% vs. 41.8%). While 5-year recurrence-free survival, cancer-specific survival (CSS) and overall survival were comparable between two groups (63.4%, 67%, and 62.1% in UraC and 61.5%, 75.9%, and 67.8% in UroBC, respectively), generally favorable prognosis for UraC in lower stages (pT1-2) but unfavorable outcomes in higher stages (pT4) compared to UroBC was observed, although only 5-year CSS in ≥ pT4 showed statistical significance (p=0.028). Body mass index (hazard ratio [HR], 0.929), diabetes mellitus (HR, 1.921), pathologic T category (HR, 3.846), and lymphovascular invasion (HR, 1.993) were predictors of CSS for all patients.
Conclusion
Despite differing histology, UraC has comparable prognosis to UroBC with relatively favorable outcome in low stages but worse prognosis in higher stages. The presented system may be useful for future grading and risk stratification of UraC.

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