1.Proarrhythmic Risk Assessment of Sildenafil under High-Dose Misuse Conditions Using the Comprehensive In Vitro Proarrhythmia Assay (CiPA)
Hanbi KIM ; Tae Woong NA ; Inkyo JUNG ; Minji KANG ; Sujeong PARK ; Chan Hyeok KWON ; Kikyung JUNG
Biomolecules & Therapeutics 2026;34(3):578-588
The comprehensive in vitro proarrhythmia assay (CiPA) initiative, led by the U.S. Food and Drug Administration (FDA), provides a framework for predicting drug-induced arrhythmia risk. To support domestic CiPA implementation, we evaluated the proarrhythmic risk of sildenafil, a phosphodiesterase type 5 (PDE5) inhibitor. Sildenafil has been misused recreationally, with reports of highdose non-medical intake. To simulate misuse, in vitro assays were conducted using concentrations up to 100× the maximum therapeutic plasma concentration (Cmax). The assessment followed the three core components of the CiPA paradigm. Patch clamp assays were conducted in Human Embryonic Kidney 293 (HEK293) and Chinese hamster ovary (CHO) cells transiently expressing Nav1.5, Cav1.2, and hERG ion channels. In silico modeling was performed using the CiPAORdv1.0 model based on IC₅₀ and Hill coefficient values. Functional evaluation included multi-electrode array (MEA) recordings in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), and in vivo electrocardiography (ECG) analysis in rats was performed to observe QT interval prolongation. Sildenafil significantly inhibited hERG currents by 40.5% at 100× Cmax. In silico modeling predicted a low Torsades de Pointes (TdP) risk based on qNet biomarkers. In contrast, MEA recordings showed a concentration-dependent prolongation of corrected field potential duration (FPDc), with a significant 13.3% increase at 100× Cmax. The TdP risk estimated from MEA modeling was 64%. In vivo ECG analysis revealed significant QT prolongation at 50× Cmax. Despite low in silico TdP predictions, functional assays suggest that high concentrations of sildenafil as in misuse may pose a clinically relevant risk of QT prolongation and arrhythmia.
2.Voice Recognition for Periodontal Probing Medical Records under Korean–English Bilingual Conditions: A Feasibility Study
Young Woo KIM ; Jin Hyeok KOOK ; Yiseul CHOI ; Wonse PARK
Healthcare Informatics Research 2026;32(2):118-124
Objectives:
This study evaluated the feasibility of voice recognition-based electronic medical record (EMR) documentation for periodontal probing in dentistry, particularly emphasizing Korean-English bilingual speech patterns and real-world clinical conditions.
Methods:
Experiments were conducted in a dental chair setting during routine clinical hours. Environmental noise levels were measured, and two microphone types (stationary and pin-type) were evaluated. Periodontal probing phrases composed of three-digit numbers and positional terms were used for speech recognition. Consistent with common clinical practice in Korea, numerical values were spoken in Korean, whereas positional terms were spoken in English. Two speech-to-text application programming interfaces, Google Cloud Speech-to-Text and Naver Clova Speech Recognition, were assessed. Recognition accuracy was evaluated for both numerical components and complete bilingual phrases.
Results:
The mean environmental noise level was 60.65 dB and was minimally influenced by activity at adjacent dental chairs. The stationary microphone failed to capture speech effectively, whereas the pin-type microphone demonstrated stable recognition performance. For three-digit number recognition, accuracy was 88.3% with Google and 96.8% with Naver. For full-phrase recognition, complete matching was achieved in 36.7% of cases for Google and 52.5% for Naver. Partial recognition occurred more frequently for numerical components than for English positional terms.
Conclusions
Voice recognition-based EMR documentation for periodontal probing demonstrated preliminary feasibility in a dental clinical environment; however, performance was influenced by Korean-English bilingual speech patterns. These findings suggest that bilingual speech characteristics should be considered when implementing voice recognition systems in dental EMR workflows. Further optimization is required before routine clinical application.
3.Usefulness of DKK1 in Estimating Vasculitis Activity and End-Stage Kidney Disease in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis Patients
Hyeok Chan KWON ; Yong-Beom PARK ; Sang-Won LEE
Yonsei Medical Journal 2026;67(1):9-16
Purpose:
To investigate whether serum levels of Dickkopf-related protein-1 (DKK1) are clinically useful in estimating cross-sectional vasculitis activity and predicting future prognosis in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV).
Materials and Methods:
This study included 76 patients with AAV. Their clinical data were retrospectively reviewed and serum DKK1 levels were measured in blood samples collected and stored at diagnosis. At diagnosis, the Birmingham vasculitis activity score (BVAS) and the five-factor score (FFS) were assessed as AAV activity indices, and the erythrocyte sedimentation rate and Creactive protein (CRP) level were recorded as acute-phase reactants. All-cause mortality and end-stage kidney disease (ESKD) were investigated as poor outcomes during follow-up.
Results:
Among the 76 patients with AAV (31 males, and 45 females), the median age was 63.5 years. At diagnosis, serum DKK1 levels were significantly correlated with BVAS, FFS, CRP, serum albumin, and serum creatinine levels. Using receiver operating characteristic curve analysis, the cut-off serum DKK1 level for predicting ESKD was determined to be 3925.0 pg/mL. Patients with serum DKK1 levels ≥3925.0 pg/mL at diagnosis displayed a significantly higher risk of ESKD progression (relative risk 5.357) and exhibited a significantly lower cumulative ESKD-free survival rate during follow-up than those with lower levels.
Conclusion
The present study is the first to demonstrate that serum DKK1 levels at diagnosis are useful in assessing vasculitis activity at diagnosis and predicting future ESKD progression in patients with AAV.
4.Therapeutic effects of Pueraria lobata (Willd.) Ohwi root and Hovenia dulcis Thunb. extracts on alcoholic liver disease: Network pharmacology and experimental validation
Zhendong Chen ; Yu Yue ; Hongyan An ; Haisu Yan ; Hyeok-Joo Park ; Pei Lin
Journal of Traditional Chinese Medical Sciences 2025;2025(1):100-111
Objective:
To investigate the protective effects of the combined concentrated liquid extract of Pueraria lobata (Willd.) Ohwi root (P. lobata, Ge Gen) and Hovenia dulcis Thunb. (H. dulcis, Zhi Ju Zi) against ethanol-induced liver damage in vitro, using a human hepatoma cell line G2 (HepG2) cell model.
Methods:
HepG2 cells were cultured in medium containing 4% ethanol to establish a model of alcoholic liver damage. The cells were then treated with the combined extract obtained via cryogenic extraction. Biochemical assays and Western blot analyses were performed to assess the levels of oxidative stress markers, antioxidant enzymes, and inflammatory cytokines. In addition, activation of the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) pathway was examined to elucidate the mechanisms underlying the effects of the extract.
Results:
Treatment with the extract contributed to a significant reduction in the release of nitric oxide and reactive oxygen species in the ethanol-treated HepG2 cells; promoted the elevated expression of superoxide dismutase, catalase, and glutathione, indicating enhanced antioxidant defenses; and showed strong free radical-scavenging activity against 1,1-diphenyl-2-picrylhydrazyl radicals. In addition, by activating the PI3K/AKT pathway, treatment promoted increases in the expression of nuclear factor erythroid 2-related factor 2 and its downstream targets, subsequently inhibiting apoptosis. Moreover. inflammatory responses were mitigated, as indicated by reductions in the expression of tumor necrosis factor-alpha and interleukin-6, and we detected reduction in the levels of alanine aminotransferase and aspartate aminotransferase, thereby indicating hepatoprotective effects.
Conclusion
The combined P. lobata root and H. dulcis extract was established to have notable antioxidative and anti-inflammatory properties, effectively alleviating ethanol-induced liver damage in vitro. These findings highlight the potential applicability of this extract as a candidate for treating alcoholic liver disease.
5.Exploring methylation signatures for high de novo recurrence risk in hepatocellular carcinoma
Da-Won KIM ; Jin Hyun PARK ; Suk Kyun HONG ; Min-Hyeok JUNG ; Ji-One PYEON ; Jin-Young LEE ; Kyung-Suk SUH ; Nam-Joon YI ; YoungRok CHOI ; Kwang-Woong LEE ; Young-Joon KIM
Clinical and Molecular Hepatology 2025;31(2):563-576
Background/Aims:
Hepatocellular carcinoma (HCC) exhibits high de novo recurrence rates post-resection. Current post-surgery recurrence prediction methods are limited, emphasizing the need for reliable biomarkers to assess recurrence risk. We aimed to develop methylation-based markers for classifying HCC patients and predicting their risk of de novo recurrence post-surgery.
Methods:
In this retrospective cohort study, we analyzed data from HCC patients who underwent surgical resection in Korea, excluding those with recurrence within one year post-surgery. Using the Infinium Methylation EPIC array on 140 samples in the discovery cohort, we classified patients into low- and high-risk groups based on methylation profiles. Distinctive markers were identified through random forest analysis. These markers were validated in the cancer genome atlas (n=217), Validation cohort 1 (n=63) and experimental Validation using a methylation-sensitive high-resolution melting (MS-HRM) assay in Validation cohort 1 and Validation cohort 2 (n=63).
Results:
The low-risk recurrence group (methylation group 1; MG1) showed a methylation average of 0.73 (95% confidence interval [CI] 0.69–0.77) with a 23.5% recurrence rate, while the high-risk group (MG2) had an average of 0.17 (95% CI 0.14–0.20) with a 44.1% recurrence rate (P<0.03). Validation confirmed the applicability of methylation markers across diverse populations, showing high accuracy in predicting the probability of HCC recurrence risk (area under the curve 96.8%). The MS-HRM assay confirmed its effectiveness in predicting de novo recurrence with 95.5% sensitivity, 89.7% specificity, and 92.2% accuracy.
Conclusions
Methylation markers effectively classified HCC patients by de novo recurrence risk, enhancing prediction accuracy and potentially offering personalized management strategies.
7.Exploring methylation signatures for high de novo recurrence risk in hepatocellular carcinoma
Da-Won KIM ; Jin Hyun PARK ; Suk Kyun HONG ; Min-Hyeok JUNG ; Ji-One PYEON ; Jin-Young LEE ; Kyung-Suk SUH ; Nam-Joon YI ; YoungRok CHOI ; Kwang-Woong LEE ; Young-Joon KIM
Clinical and Molecular Hepatology 2025;31(2):563-576
Background/Aims:
Hepatocellular carcinoma (HCC) exhibits high de novo recurrence rates post-resection. Current post-surgery recurrence prediction methods are limited, emphasizing the need for reliable biomarkers to assess recurrence risk. We aimed to develop methylation-based markers for classifying HCC patients and predicting their risk of de novo recurrence post-surgery.
Methods:
In this retrospective cohort study, we analyzed data from HCC patients who underwent surgical resection in Korea, excluding those with recurrence within one year post-surgery. Using the Infinium Methylation EPIC array on 140 samples in the discovery cohort, we classified patients into low- and high-risk groups based on methylation profiles. Distinctive markers were identified through random forest analysis. These markers were validated in the cancer genome atlas (n=217), Validation cohort 1 (n=63) and experimental Validation using a methylation-sensitive high-resolution melting (MS-HRM) assay in Validation cohort 1 and Validation cohort 2 (n=63).
Results:
The low-risk recurrence group (methylation group 1; MG1) showed a methylation average of 0.73 (95% confidence interval [CI] 0.69–0.77) with a 23.5% recurrence rate, while the high-risk group (MG2) had an average of 0.17 (95% CI 0.14–0.20) with a 44.1% recurrence rate (P<0.03). Validation confirmed the applicability of methylation markers across diverse populations, showing high accuracy in predicting the probability of HCC recurrence risk (area under the curve 96.8%). The MS-HRM assay confirmed its effectiveness in predicting de novo recurrence with 95.5% sensitivity, 89.7% specificity, and 92.2% accuracy.
Conclusions
Methylation markers effectively classified HCC patients by de novo recurrence risk, enhancing prediction accuracy and potentially offering personalized management strategies.
10.DRG2 levels in prostate cancer cell lines predict response to PARP inhibitor during docetaxel treatment
Jeong Min LEE ; Won Hyeok LEE ; Seung Hyeon CHO ; Jeong Woo PARK ; Hyuk Nam KWON ; Ji Hye KIM ; Sang Hun LEE ; Ji Hyung YOON ; Sungchan PARK ; Seong Cheol KIM
Investigative and Clinical Urology 2025;66(1):56-66
Purpose:
Developmentally regulated GTP-binding protein 2 (DRG2) regulates microtubule dynamics and G2/M arrest during docetaxel treatment. Poly ADP-ribose polymerase (PARP) acts as an important repair system for DNA damage caused by docetaxel treatment. This study investigated whether DRG2 expression affects response to PARP inhibitors (olaparib) using prostate cancer cell lines PC3, DU145, LNCaP-FGC, and LNCaP-LN3.
Materials and Methods:
The cell viability and DRG2 expression levels were assessed using colorimetric-based cell viability assay and western blot. Cells were transfected with DRG2 siRNA, and pcDNA6/V5-DRG2 was used to overexpress DRG2. Flow cytometry was applied for cell cycle assay and apoptosis analysis using the Annexing V cell death assay.
Results:
The expression of DRG2 was highest in LNCaP-LN3 and lowest in DU145 cells. Expressions of p53 in PC3, DU145, and the two LNCaP cell lines were null-type, high-expression, and medium-expression, respectively. In PC3 (DRG2 high, p53 null) cells, docetaxel increased G2/M arrest without apoptosis; however, subsequent treatment with olaparib promoted apoptosis. In DU145 and LNCaP-FGC (DRG2 low), docetaxel increased sub-G1 but not G2/M arrest and induced apoptosis, whereas olaparib had no additional effect. In LNCaP-LN3 (DRG2 high, p53 wild-type), docetaxel increased sub-G1 and G2/M arrest, furthermore olaparib enhanced cell death. Docetaxel and olaparib combination treatment had a slight effect on DRG2 knockdown PC3, but increased apoptosis in DRG2-overexpressed DU145 cells.
Conclusions
DRG2 and p53 expressions play an important role in prostate cancer cell lines treated with docetaxel, and DRG2 levels can predict the response to PARP inhibitors.


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