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.DentalRegiformer: A Fully Automated Deep Learning Framework for Coarse-to-Fine Registration between Intraoral Scan and CBCT Image
Heejin YUN ; Yubin LEE ; Jimin SUN ; Whaeum LEE ; Dahee KIM ; Won-Jin YI
Journal of Korean Dental Science 2025;18(4):161-176
Purpose:
Precise registration between intraoral scans (IOSs) and CBCT images is essential for many digital dentistry applications. The purpose of this study was to develop DentalRegiformer, a fully automated, end-to-end deep learning framework that ensures accurate registration between IOS and CBCT images.
Materials and Methods:
The network was trained on 88 paired CBCT-IOS datasets from 44 patients, with ground-truth alignments obtained through manual registration performed by trained dental students. To enhance clinical accuracy and efficiency, a multi-stage coarse-to-fine strategy is proposed to integrate segmentation, classification, and registration into a unified pipeline. First, tooth segmentation is performed on CBCT volumes using 3D nnU-Net to generate segmented tooth regions for alignment. Simultaneously, IOS datasets are classified as maxillary or mandibular dentition using a hybrid representation that combines geometric descriptors with point cloud features extracted via a DGCNN network. Registration is then conducted in two phases: coarse alignment using a DCP framework for feature encoding and probabilistic correspondence estimation to compute the initial rigid transformation, followed by fine alignment using GeoTransformer’s local-to-global iterative refinement, which alternates between local feature aggregation and global context integration to progressively enhance correspondence accuracy and achieve precise rigid registration.
Results
The segmentation model achieved robust results, with a Dice coefficient of 0.924, precision of 0.916, and recall of 0.934. The DGCNN classifier perfectly distinguished maxillary and mandibular arches, achieving sensitivity, specificity, ROC, and accuracy of 1.000.For registration, DentalRegiformer accurately predicted transformation between IOS and CBCT images, yielding an overall RMSE of 0.556 mm; MAEs of 0.231mm, 0.329 mm, and 0.283 mm along the x-, y-, and z-axes, respectively; and inference time of 19.623 seconds. In comparison, the manual method based on combined pair-points and ICP had an RMSE of 0.615 mm;MAEs of 0.244 mm, 0.347 mm, and 0.298 mm along the x-, y-, and z-axes, respectively; and processing time of 431.6 seconds.Discussion and Conclusion: Therefore, DentalRegiformer is a fully automated, deep learning–based solution that minimizes manual intervention and improves clinical efficiency. The framework streamlines digital dental workflows, reduces operator-dependent errors, and facilitates automated, personalized dental care.
3.Introduction to the forensic research via omics markers in environmental health vulnerable areas (FROM) study
Jung-Yeon KWON ; Woo Jin KIM ; Yong Min CHO ; Byoung-gwon KIM ; Seungho LEE ; Jee Hyun RHO ; Sang-Yong EOM ; Dahee HAN ; Kyung-Hwa CHOI ; Jang-Hee LEE ; Jeeyoung KIM ; Sungho WON ; Hee-Gyoo KANG ; Sora MUN ; Hyun Ju YOO ; Jung-Woong KIM ; Kwan LEE ; Won-Ju PARK ; Seongchul HONG ; Young-Seoub HONG
Epidemiology and Health 2024;46(1):e2024062-
This research group (forensic research via omics markers in environmental health vulnerable areas: FROM) aimed to develop biomarkers for exposure to environmental hazards and diseases, assess environmental diseases, and apply and verify these biomarkers in environmentally vulnerable areas. Environmentally vulnerable areas—including refineries, abandoned metal mines, coal-fired power plants, waste incinerators, cement factories, and areas with high exposure to particulate matter—along with control areas, were selected for epidemiological investigations. A total of 1,157 adults, who had resided in these areas for over 10 years, were recruited between June 2021 and September 2023. Personal characteristics of the study participants were gathered through a survey. Biological samples, specifically blood and urine, were collected during the field investigations, separated under refrigerated conditions, and then transported to the laboratory for biomarker analysis. Analyses of heavy metals, environmental hazards, and adducts were conducted on these blood and urine samples. Additionally, omics analyses of epigenomes, proteomes, and metabolomes were performed using the blood samples. The biomarkers identified in this study will be utilized to assess the risk of environmental disease occurrence and to evaluate the impact on the health of residents in environmentally vulnerable areas, following the validation of diagnostic accuracy for these diseases.
4.Introduction to the forensic research via omics markers in environmental health vulnerable areas (FROM) study
Jung-Yeon KWON ; Woo Jin KIM ; Yong Min CHO ; Byoung-gwon KIM ; Seungho LEE ; Jee Hyun RHO ; Sang-Yong EOM ; Dahee HAN ; Kyung-Hwa CHOI ; Jang-Hee LEE ; Jeeyoung KIM ; Sungho WON ; Hee-Gyoo KANG ; Sora MUN ; Hyun Ju YOO ; Jung-Woong KIM ; Kwan LEE ; Won-Ju PARK ; Seongchul HONG ; Young-Seoub HONG
Epidemiology and Health 2024;46(1):e2024062-
This research group (forensic research via omics markers in environmental health vulnerable areas: FROM) aimed to develop biomarkers for exposure to environmental hazards and diseases, assess environmental diseases, and apply and verify these biomarkers in environmentally vulnerable areas. Environmentally vulnerable areas—including refineries, abandoned metal mines, coal-fired power plants, waste incinerators, cement factories, and areas with high exposure to particulate matter—along with control areas, were selected for epidemiological investigations. A total of 1,157 adults, who had resided in these areas for over 10 years, were recruited between June 2021 and September 2023. Personal characteristics of the study participants were gathered through a survey. Biological samples, specifically blood and urine, were collected during the field investigations, separated under refrigerated conditions, and then transported to the laboratory for biomarker analysis. Analyses of heavy metals, environmental hazards, and adducts were conducted on these blood and urine samples. Additionally, omics analyses of epigenomes, proteomes, and metabolomes were performed using the blood samples. The biomarkers identified in this study will be utilized to assess the risk of environmental disease occurrence and to evaluate the impact on the health of residents in environmentally vulnerable areas, following the validation of diagnostic accuracy for these diseases.
5.Introduction to the forensic research via omics markers in environmental health vulnerable areas (FROM) study
Jung-Yeon KWON ; Woo Jin KIM ; Yong Min CHO ; Byoung-gwon KIM ; Seungho LEE ; Jee Hyun RHO ; Sang-Yong EOM ; Dahee HAN ; Kyung-Hwa CHOI ; Jang-Hee LEE ; Jeeyoung KIM ; Sungho WON ; Hee-Gyoo KANG ; Sora MUN ; Hyun Ju YOO ; Jung-Woong KIM ; Kwan LEE ; Won-Ju PARK ; Seongchul HONG ; Young-Seoub HONG
Epidemiology and Health 2024;46(1):e2024062-
This research group (forensic research via omics markers in environmental health vulnerable areas: FROM) aimed to develop biomarkers for exposure to environmental hazards and diseases, assess environmental diseases, and apply and verify these biomarkers in environmentally vulnerable areas. Environmentally vulnerable areas—including refineries, abandoned metal mines, coal-fired power plants, waste incinerators, cement factories, and areas with high exposure to particulate matter—along with control areas, were selected for epidemiological investigations. A total of 1,157 adults, who had resided in these areas for over 10 years, were recruited between June 2021 and September 2023. Personal characteristics of the study participants were gathered through a survey. Biological samples, specifically blood and urine, were collected during the field investigations, separated under refrigerated conditions, and then transported to the laboratory for biomarker analysis. Analyses of heavy metals, environmental hazards, and adducts were conducted on these blood and urine samples. Additionally, omics analyses of epigenomes, proteomes, and metabolomes were performed using the blood samples. The biomarkers identified in this study will be utilized to assess the risk of environmental disease occurrence and to evaluate the impact on the health of residents in environmentally vulnerable areas, following the validation of diagnostic accuracy for these diseases.
6.Introduction to the forensic research via omics markers in environmental health vulnerable areas (FROM) study
Jung-Yeon KWON ; Woo Jin KIM ; Yong Min CHO ; Byoung-gwon KIM ; Seungho LEE ; Jee Hyun RHO ; Sang-Yong EOM ; Dahee HAN ; Kyung-Hwa CHOI ; Jang-Hee LEE ; Jeeyoung KIM ; Sungho WON ; Hee-Gyoo KANG ; Sora MUN ; Hyun Ju YOO ; Jung-Woong KIM ; Kwan LEE ; Won-Ju PARK ; Seongchul HONG ; Young-Seoub HONG
Epidemiology and Health 2024;46(1):e2024062-
This research group (forensic research via omics markers in environmental health vulnerable areas: FROM) aimed to develop biomarkers for exposure to environmental hazards and diseases, assess environmental diseases, and apply and verify these biomarkers in environmentally vulnerable areas. Environmentally vulnerable areas—including refineries, abandoned metal mines, coal-fired power plants, waste incinerators, cement factories, and areas with high exposure to particulate matter—along with control areas, were selected for epidemiological investigations. A total of 1,157 adults, who had resided in these areas for over 10 years, were recruited between June 2021 and September 2023. Personal characteristics of the study participants were gathered through a survey. Biological samples, specifically blood and urine, were collected during the field investigations, separated under refrigerated conditions, and then transported to the laboratory for biomarker analysis. Analyses of heavy metals, environmental hazards, and adducts were conducted on these blood and urine samples. Additionally, omics analyses of epigenomes, proteomes, and metabolomes were performed using the blood samples. The biomarkers identified in this study will be utilized to assess the risk of environmental disease occurrence and to evaluate the impact on the health of residents in environmentally vulnerable areas, following the validation of diagnostic accuracy for these diseases.
7.Inhibition of Class I Histone Deacetylase Enhances Self-Reprogramming of Spermatogonial Stem Cells into Pluripotent Stem Cells
Yukyeong LEE ; Seung-Won LEE ; Dahee JEONG ; Hye Jeong LEE ; Na Young CHOI ; Jin Seok BANG ; Seokbeom HAM ; Kinarm KO
International Journal of Stem Cells 2023;16(1):27-35
Background and Objectives:
Spermatogonial stem cells (SSCs) are the most primitive cells in spermatogenesis and are the only adult stem cells capable of passing on the genome of a given species to the next generation. SSCs are the only adult stem cells known to exhibit high Oct4 expression and can be induced to self-reprogram into pluripotent cells depending on culture conditions. Epigenetic modulation is well known to be involved in the induction of pluripotency of somatic cells. However, epigenetic modulation in self-reprogramming of SSCs into pluripotent cells has not been studied.
Methods:
and Results: In this study, we examined the involvement of epigenetic modulation by assessing whether selfreprogramming of SSCs is enhanced by treatment with epigenetic modulators. We found that second-generation selective class I HDAC inhibitors increased SSC reprogramming efficiency, whereas non-selective HDAC inhibitors had no effect.
Conclusions
We showed that pluripotent stem cells derived from adult SSCs by treatment with small molecules with epigenetic modulator functions exhibit pluripotency in vitro and in vivo. Our results suggest that the mechanism of SSC reprogramming by epigenetic modulator can be used for important applications in epigenetic reprogramming research.
8.Retropharyngeal Ectopic Parathyroid Adenoma Localized by 18F-Fluorocholine Positron Emission Tomography/Computed Tomography: A Case Report
Hyeokjoo JANG ; Seunghyun LEE ; Dahee KIM ; Namki HONG
Journal of Bone Metabolism 2022;29(3):197-203
Ectopic parathyroid adenomas of the retropharyngeal space are relatively rare. Herein, we report a case of primary hyperparathyroidism (PHPT) secondary to a retropharyngeal parathyroid adenoma. A 22-year-old woman presented with elevated serum calcium and parathyroid hormone (PTH) levels, revealed during a medical check-up. The patient had a history of ureteral stones and a confirmed low bone mass. Neck 99mTechnetium-sestamibi singlephoton emission computed tomography (CT) and ultrasonography did not reveal any suspicious lesions. There was no evidence of hereditary PHPT based on the results of targeted gene sequencing. Surgical exploration was unsuccessful, and the PHPT persisted after the first surgery. Approximately a year after the failed operation, 18F-fluorocholine (FCH) positron emission tomography/CT (PET-CT) became available, and when performed, it revealed increased uptake in the retropharyngeal space of the right side of the neck. The results of parathyroid venous sampling were concordant with a >2-fold elevation of PTH level in the veins on the right side of the neck compared to the peripheral veins. The 1.8 cm-diameter mass was successfully removed resulting in an 87% reduction in intraoperative PTH level (198.0-26.5 pg/mL). Subsequently, normalizations of calcium and PTH levels were achieved. In summary, ectopic parathyroid adenomas, including retropharyngeal lesions, should also be suspected when investigating an elusive case of PHPT. 18F-FCH PET-CT can be a useful complementary modality for detecting culprit lesions.
9.Source Analysis and Effective Control of a COVID-19 Outbreak in a University Teaching Hospital during a Period of Increasing Community Prevalence of COVID-19
Unhee LEE ; Seong Eun KIM ; Seung Yeob LEE ; Hang Nam WI ; Okja CHOI ; Ji-Won PARK ; Dahee KIM ; You Jung KIM ; Hwa Young SHIN ; Mihee KIM ; Eun Ji KIM ; Seung-Ji KANG ; Sook-In JUNG ; Kyung-Hwa PARK
Journal of Korean Medical Science 2021;36(24):e179-
Background:
South Korea has been experiencing a third wave of coronavirus disease 2019 (COVID-19) since mid-November 2020. Our hospital in Gwangju metropolitan city experienced a healthcare-associated COVID-19 outbreak early in the third wave. The first confirmed COVID-19 patient was a symptomatic neurosurgery resident with high mobility throughout the hospital. We analyzed the transmission routes of nosocomial COVID-19 and discussed infection control strategies.
Methods:
We retrospectively analyzed the severe acute respiratory syndrome coronavirus 2 reverse transcription-polymerase chain reaction (RT-PCR) testing results according to time point and evaluated transmission routes.
Results:
Since COVID-19 was first confirmed in a healthcare worker (HCW) on 11/13/2020, we performed RT-PCR tests for all patients and caregivers and four complete enumeration surveys for all HCWs. We detected three clusters of nosocomial spread and several sporadic cases. The first cluster originated from the community outbreak spot, where an asymptomatic HCW visited, which led to a total of 22 cases. The second cluster, which included patient-to-patient transmission, originated from a COVID-19 positive caregiver before diagnosis and the third cluster involved a radiologist and a banker. We took measures to isolate Building 1 of the hospital for 17 days and controlled the outbreak during a period of increasing community COVID-19 prevalence. Universal screening of all inpatients upon admission and resident caregivers was made mandatory and hospital-related employees are now screened monthly.
Conclusion
Infection control strategies to prevent the nosocomial transmission of emerging infectious diseases must correspond with community disease prevalence. Our data reinforce the importance of multi-time point surveillance of asymptomatic HCWs and routine surveillance of patients and caregivers during an epidemic.
10.Source Analysis and Effective Control of a COVID-19 Outbreak in a University Teaching Hospital during a Period of Increasing Community Prevalence of COVID-19
Unhee LEE ; Seong Eun KIM ; Seung Yeob LEE ; Hang Nam WI ; Okja CHOI ; Ji-Won PARK ; Dahee KIM ; You Jung KIM ; Hwa Young SHIN ; Mihee KIM ; Eun Ji KIM ; Seung-Ji KANG ; Sook-In JUNG ; Kyung-Hwa PARK
Journal of Korean Medical Science 2021;36(24):e179-
Background:
South Korea has been experiencing a third wave of coronavirus disease 2019 (COVID-19) since mid-November 2020. Our hospital in Gwangju metropolitan city experienced a healthcare-associated COVID-19 outbreak early in the third wave. The first confirmed COVID-19 patient was a symptomatic neurosurgery resident with high mobility throughout the hospital. We analyzed the transmission routes of nosocomial COVID-19 and discussed infection control strategies.
Methods:
We retrospectively analyzed the severe acute respiratory syndrome coronavirus 2 reverse transcription-polymerase chain reaction (RT-PCR) testing results according to time point and evaluated transmission routes.
Results:
Since COVID-19 was first confirmed in a healthcare worker (HCW) on 11/13/2020, we performed RT-PCR tests for all patients and caregivers and four complete enumeration surveys for all HCWs. We detected three clusters of nosocomial spread and several sporadic cases. The first cluster originated from the community outbreak spot, where an asymptomatic HCW visited, which led to a total of 22 cases. The second cluster, which included patient-to-patient transmission, originated from a COVID-19 positive caregiver before diagnosis and the third cluster involved a radiologist and a banker. We took measures to isolate Building 1 of the hospital for 17 days and controlled the outbreak during a period of increasing community COVID-19 prevalence. Universal screening of all inpatients upon admission and resident caregivers was made mandatory and hospital-related employees are now screened monthly.
Conclusion
Infection control strategies to prevent the nosocomial transmission of emerging infectious diseases must correspond with community disease prevalence. Our data reinforce the importance of multi-time point surveillance of asymptomatic HCWs and routine surveillance of patients and caregivers during an epidemic.

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