1.The Effects of Nicotine on Re-endothelialization, Inflammation, and Neoatherosclerosis After Drug-Eluting Stent Implantation in a Porcine Model
Seok OH ; Ju Han KIM ; Saleem AHMAD ; Yu Jeong JIN ; Mi Hyang NA ; Munki KIM ; Jeong Ha KIM ; Dae Sung PARK ; Dae Young HYUN ; Kyung Hoon CHO ; Min Chul KIM ; Doo Sun SIM ; Young Joon HONG ; Seung-won LEE ; Youngkeun AHN ; Myung Ho JEONG
Korean Circulation Journal 2025;55(1):50-64
Background and Objectives:
Cigarette smoking is a major risk factor for atherosclerosis.Nicotine, a crucial constituent of tobacco, contributes to atherosclerosis development and progression. However, evidence of the association between nicotine and neointima formation is limited. We aimed to evaluate whether nicotine enhances neointimal hyperplasia in the native epicardial coronary arteries of pigs after percutaneous coronary intervention (PCI) with drug-eluting stents (DES).
Methods:
After coronary angiography (CAG) and quantitative coronary angiography (QCA), we implanted 20 DES into 20 pigs allocated to 2 groups: no-nicotine (n=10) and nicotine (n=10) groups. Post-PCI CAG and QCA were performed immediately. Follow-up CAG, QCA, optical coherence tomography (OCT), and histopathological analyses were performed 2 months post-PCI.
Results:
Despite intergroup similarities in the baseline QCA findings, OCT analysis showed that the nicotine group had a smaller mean stent and lumen areas, a larger mean neointimal area, greater percent area stenosis, and higher peri-strut fibrin and inflammation scores than the no-nicotine group. In immunofluorescence analysis, the nicotine group displayed higher expression of CD68 and α-smooth muscle actin but lower CD31 expression than the no-nicotine group.
Conclusions
Nicotine inhibited re-endothelialization and promoted inflammation and NIH after PCI with DES in a porcine model.
2.YAK577 Attenuates Cardiac Remodeling and Fibrosis in Isoproterenol-Infused Heart Failure Mice by Downregulating MMP12
Hongyan ZHOU ; Hae Jin KEE ; Le WAN ; Yodita ASFAHA ; Fabian FISCHER ; Matthias U KASSACK ; Thomas KURZ ; Seong Hoon KIM ; Seung-Jung KEE ; Young Joon HONG ; Myung Ho JEONG
Korean Circulation Journal 2025;55(3):231-247
Background and Objectives:
Heart failure is a potentially fatal event caused by diverse cardiovascular diseases, leading to high morbidity and mortality. Histone deacetylase (HDAC) inhibitors positively influence cardiac hypertrophy, fibrosis, hypertension, myocardial infarction, and heart failure, causing some side effects. We aimed to investigate the effect of the novel HDAC inhibitor YAK577 on the heart failure mouse model and its underlying mechanism.
Methods:
New hydroxamic acid YAK577 was prepared via methyl-2,3-diphenylpropanoate synthesis using carboxylic acids. We used a micro-osmotic pump, including isoproterenol (ISO; 80 mg/kg/day), to induce a heart failure with reduced ejection fraction. Cardiac hypertrophy was assessed by heart weight to body weight ratio and cross-sectional area.The left ventricular (LV) function was assessed by echocardiography. Fibrosis was evaluated using picrosirius red staining. Overexpression and knockdown experiments were performed to investigate the association between HDAC8 and matrix metalloproteinase 12 (MMP12).
Results:
YAK577 treatment restored ISO-induced reduction in LV fractional shortening and ejection fraction (n=9–11). YAK577 significantly downregulated cardiac hypertrophy marker genes (natriuretic peptide B, NPPB, and myosin heavy chain 7, MYH7) and cardiomyocyte size in vitro but not in vivo. YAK577 ameliorated cardiac fibrosis and fibrosis-related genes in vivo and in vitro. Additionally, YAK577 reduced elevated HDAC8 and MMP12 mRNA and protein expressions in ISO-infused mice, H9c2 cells, and rat neonatal cardiomyocytes.HDAC8 overexpression stimulated MMP12 and NPPB mRNA levels, while HDAC8 knockdown downregulated these genes.
Conclusions
YAK577 acts as a novel heart failure drug through the HDAC8/MMP12 pathway.
3.Characteristics and Prevalence of Sequelae after COVID-19: A Longitudinal Cohort Study
Se Ju LEE ; Yae Jee BAEK ; Su Hwan LEE ; Jung Ho KIM ; Jin Young AHN ; Jooyun KIM ; Ji Hoon JEON ; Hyeri SEOK ; Won Suk CHOI ; Dae Won PARK ; Yunsang CHOI ; Kyoung-Ho SONG ; Eu Suk KIM ; Hong Bin KIM ; Jae-Hoon KO ; Kyong Ran PECK ; Jae-Phil CHOI ; Jun Hyoung KIM ; Hee-Sung KIM ; Hye Won JEONG ; Jun Yong CHOI
Infection and Chemotherapy 2025;57(1):72-80
Background:
The World Health Organization has declared the end of the coronavirus disease 2019 (COVID-19) public health emergency. However, this did not indicate the end of COVID-19. Several months after the infection, numerous patients complain of respiratory or nonspecific symptoms; this condition is called long COVID. Even patients with mild COVID-19 can experience long COVID, thus the burden of long COVID remains considerable. Therefore, we conducted this study to comprehensively analyze the effects of long COVID using multi-faceted assessments.
Materials and Methods:
We conducted a prospective cohort study involving patients diagnosed with COVID-19 between February 2020 and September 2021 in six tertiary hospitals in Korea. Patients were followed up at 1, 3, 6, 12, 18, and 24 months after discharge. Long COVID was defined as the persistence of three or more COVID-19-related symptoms. The primary outcome of this study was the prevalence of long COVID after the period of COVID-19.
Results:
During the study period, 290 patients were enrolled. Among them, 54.5 and 34.6% experienced long COVID within 6 months and after more than 18 months, respectively. Several patients showed abnormal results when tested for post-traumatic stress disorder (17.4%) and anxiety (31.9%) after 18 months. In patients who underwent follow-up chest computed tomography 18 months after COVID-19, abnormal findings remained at 51.9%. Males (odds ratio [OR], 0.17; 95% confidence interval [CI], 0.05–0.53; P=0.004) and elderly (OR, 1.04; 95% CI, 1.00–1.09; P=0.04) showed a significant association with long COVID after 12–18 months in a multivariable logistic regression analysis.
Conclusion
Many patients still showed long COVID after 18 months post SARS-CoV-2 infection. When managing these patients, the assessment of multiple aspects is necessary.
4.The Effects of Nicotine on Re-endothelialization, Inflammation, and Neoatherosclerosis After Drug-Eluting Stent Implantation in a Porcine Model
Seok OH ; Ju Han KIM ; Saleem AHMAD ; Yu Jeong JIN ; Mi Hyang NA ; Munki KIM ; Jeong Ha KIM ; Dae Sung PARK ; Dae Young HYUN ; Kyung Hoon CHO ; Min Chul KIM ; Doo Sun SIM ; Young Joon HONG ; Seung-won LEE ; Youngkeun AHN ; Myung Ho JEONG
Korean Circulation Journal 2025;55(1):50-64
Background and Objectives:
Cigarette smoking is a major risk factor for atherosclerosis.Nicotine, a crucial constituent of tobacco, contributes to atherosclerosis development and progression. However, evidence of the association between nicotine and neointima formation is limited. We aimed to evaluate whether nicotine enhances neointimal hyperplasia in the native epicardial coronary arteries of pigs after percutaneous coronary intervention (PCI) with drug-eluting stents (DES).
Methods:
After coronary angiography (CAG) and quantitative coronary angiography (QCA), we implanted 20 DES into 20 pigs allocated to 2 groups: no-nicotine (n=10) and nicotine (n=10) groups. Post-PCI CAG and QCA were performed immediately. Follow-up CAG, QCA, optical coherence tomography (OCT), and histopathological analyses were performed 2 months post-PCI.
Results:
Despite intergroup similarities in the baseline QCA findings, OCT analysis showed that the nicotine group had a smaller mean stent and lumen areas, a larger mean neointimal area, greater percent area stenosis, and higher peri-strut fibrin and inflammation scores than the no-nicotine group. In immunofluorescence analysis, the nicotine group displayed higher expression of CD68 and α-smooth muscle actin but lower CD31 expression than the no-nicotine group.
Conclusions
Nicotine inhibited re-endothelialization and promoted inflammation and NIH after PCI with DES in a porcine model.
5.YAK577 Attenuates Cardiac Remodeling and Fibrosis in Isoproterenol-Infused Heart Failure Mice by Downregulating MMP12
Hongyan ZHOU ; Hae Jin KEE ; Le WAN ; Yodita ASFAHA ; Fabian FISCHER ; Matthias U KASSACK ; Thomas KURZ ; Seong Hoon KIM ; Seung-Jung KEE ; Young Joon HONG ; Myung Ho JEONG
Korean Circulation Journal 2025;55(3):231-247
Background and Objectives:
Heart failure is a potentially fatal event caused by diverse cardiovascular diseases, leading to high morbidity and mortality. Histone deacetylase (HDAC) inhibitors positively influence cardiac hypertrophy, fibrosis, hypertension, myocardial infarction, and heart failure, causing some side effects. We aimed to investigate the effect of the novel HDAC inhibitor YAK577 on the heart failure mouse model and its underlying mechanism.
Methods:
New hydroxamic acid YAK577 was prepared via methyl-2,3-diphenylpropanoate synthesis using carboxylic acids. We used a micro-osmotic pump, including isoproterenol (ISO; 80 mg/kg/day), to induce a heart failure with reduced ejection fraction. Cardiac hypertrophy was assessed by heart weight to body weight ratio and cross-sectional area.The left ventricular (LV) function was assessed by echocardiography. Fibrosis was evaluated using picrosirius red staining. Overexpression and knockdown experiments were performed to investigate the association between HDAC8 and matrix metalloproteinase 12 (MMP12).
Results:
YAK577 treatment restored ISO-induced reduction in LV fractional shortening and ejection fraction (n=9–11). YAK577 significantly downregulated cardiac hypertrophy marker genes (natriuretic peptide B, NPPB, and myosin heavy chain 7, MYH7) and cardiomyocyte size in vitro but not in vivo. YAK577 ameliorated cardiac fibrosis and fibrosis-related genes in vivo and in vitro. Additionally, YAK577 reduced elevated HDAC8 and MMP12 mRNA and protein expressions in ISO-infused mice, H9c2 cells, and rat neonatal cardiomyocytes.HDAC8 overexpression stimulated MMP12 and NPPB mRNA levels, while HDAC8 knockdown downregulated these genes.
Conclusions
YAK577 acts as a novel heart failure drug through the HDAC8/MMP12 pathway.
6.Part 1. Current Status of Hearing Loss Patients in Korea Using National Data: National Health Insurance Service- Database, 2010 to 2020
Junhun LEE ; Chul Young YOON ; Jiwon KIM ; In-Ki JIN ; Michelle J. SUH ; Wan-Ho CHO ; Hyo-Jeong LEE ; Seong Jun CHOI ; Dongchul CHA ; Kyung Ho PARK ; Soo Hee OH ; Young Joon SEO ; Tae Hoon KONG
Korean Journal of Otolaryngology - Head and Neck Surgery 2025;68(1):7-18
Background and Objectives:
Hearing loss significantly affects communication, psychosocial well-being, and quality of life. This study analyzes the National Health Insurance Service database to assess the trends and characteristics of hearing loss in South Korea from 2010 to 2020.Subjects and Method The database encompasses 97% of the Korean population, providing comprehensive data on medical history, prescriptions, and health examinations. The analysis used the World Health Organization’s ICD-10 definitions to categorize hearing loss types and examine their prevalence and incidence across various demographics over 11 years.
Results:
There was an overall annual increase of 4.62% in diagnosed cases of hearing loss, with the most significant rise among the elderly. The rate of increase accelerated from 3.32% between 2010 and 2014 to 6.49% between 2014 and 2020, corresponding with the improved hearing aid access facilitated by policy changes. Women showed a slightly higher increase than men. The data also indicated a consistent rise in abnormal hearing test results during health examinations, especially in older adults.
Conclusion
The study highlights an increasing trend in hearing loss diagnoses, driven by an aging population and enhanced detection facilitated by policy changes. These findings emphasize the need for continuous monitoring and targeted health policies to manage hearing loss effectively, offering valuable insights for global health management and policy development.
7.Part 2. Current Status of Hearing Disability and Hearing Rehabilitation Devices in Korea Using National Data: NHIS-Database, 2010 to 2020
Junhun LEE ; Chul Young YOON ; Jiwon KIM ; In-Ki JIN ; Michelle J. SUH ; Wan-Ho CHO ; Hyo-Jeong LEE ; Seong Jun CHOI ; Dongchul CHA ; Kyung Ho PARK ; Soo Hee OH ; Young Joon SEO ; Tae Hoon KONG
Korean Journal of Otolaryngology - Head and Neck Surgery 2025;68(3):94-104
Background and Objectives:
This study aims to analyze trends in hearing disability and the use of hearing rehabilitation devices (hearing aids and cochlear implants) in South Korea over the past 11 years (2010-2020) using data from the National Health Insurance Service (NHIS).Subjects and Method Data were extracted from the NHIS database, covering approximately 97% of the South Korean population. Patients diagnosed with hearing loss were classified using ICD-10 codes. The data were analyzed to determine trends in hearing disability, hearing aid prescriptions, and cochlear implant usage by age, gender, and types and causes of hearing loss.
Results:
The number of hearing disability patients increased from 170900 in 2010 to 362738 in 2020, with an annual growth rate of 7.95%. The highest increase was observed in the ≥60 age group, with an annual growth rate of 11.04%. Hearing aid prescriptions rose from 4966 in 2010 to 11974 in 2020, showing a 10.45% annual increase. Females showed a higher growth rate in both hearing disability and hearing aid prescriptions compared to males. Cochlear implant prescriptions also increased, particularly among older adults.
Conclusion
The study highlights a significant rise in hearing disability and the use of hearing aids and cochlear implants in South Korea, especially among the elderly. The findings underscore the importance of early diagnosis and intervention for hearing loss and the need for policy improvements to enhance accessibility and affordability of hearing rehabilitation services. Additional strategies are needed to ensure appropriate hearing rehabilitation for those not yet receiving adequate care.
8.Radiofrequency Ablation for Recurrent Thyroid Cancers:2025 Korean Society of Thyroid Radiology Guideline
Eun Ju HA ; Min Kyoung LEE ; Jung Hwan BAEK ; Hyun Kyung LIM ; Hye Shin AHN ; Seon Mi BAEK ; Yoon Jung CHOI ; Sae Rom CHUNG ; Ji-hoon KIM ; Jae Ho SHIN ; Ji Ye LEE ; Min Ji HONG ; Hyun Jin KIM ; Leehi JOO ; Soo Yeon HAHN ; So Lyung JUNG ; Chang Yoon LEE ; Jeong Hyun LEE ; Young Hen LEE ; Jeong Seon PARK ; Jung Hee SHIN ; Jin Yong SUNG ; Miyoung CHOI ; Dong Gyu NA ;
Korean Journal of Radiology 2025;26(1):10-28
Radiofrequency ablation (RFA) is a minimally invasive treatment modality used as an alternative to surgery in patients with benign thyroid nodules, recurrent thyroid cancers (RTCs), and primary thyroid microcarcinomas. The Korean Society of Thyroid Radiology (KSThR) initially developed recommendations for the optimal use of RFA for thyroid tumors in 2009 and revised them in 2012 and 2017. As new meaningful evidence has accumulated since 2017 and in response to a growing global interest in the use of RFA for treating malignant thyroid lesions, the task force committee members of the KSThR decided to update the guidelines on the use of RFA for the management of RTCs based on a comprehensive analysis of current literature and expert consensus.
9.Radiologic evolution of biopsy-proven acute interstitial nephritis: a multimodal imaging case report
Euljo JEONG ; Bong Soo PARK ; Il Hwan KIM ; Jung Hee SON ; Kyung Han NAM ; Yoon Ho LEE ; Yoo Jin LEE
Kosin Medical Journal 2025;40(1):72-79
This report presents radiologic changes after clinical improvement in a patient with acute interstitial nephritis (AIN). A 45-year-old female patient was referred for decreased renal function. Eight months prior, she had undergone hysterectomy and received chemotherapy. At the start of chemotherapy, her baseline creatinine level was 0.55 mg/dL, which rose to 1.46 mg/dL. Multiple imaging modalities performed when decreased renal function was observed revealed bilateral renal enlargement with increased cortical attenuation on computed tomography (CT), cortical hyperechogenicity on ultrasonography, and diffusion restriction in the renal cortices on magnetic resonance imaging. A renal biopsy was performed, and AIN was diagnosed. Follow-up laboratory tests showed that kidney function had improved to normal levels, and CT at that time showed a reduction in the size of both kidneys. Radiologic changes can serve as clues for the diagnosis of AIN. This is the first report to confirm radiological changes after the clinical improvement of AIN, thereby providing novel information about the course of AIN.
10.Permanent Congenital Hypothyroidism in Very Low Birth Weight Infants: A Single Center’s Experience
Joo Hyung ROH ; Tae-Gyeong KIM ; Keon Hee SEOL ; Chae Young KIM ; Soo Hyun KIM ; Ji Yoon JEONG ; Ja Hye KIM ; Euiseok JUNG ; Jin-Ho CHOI ; Byong Sop LEE
Neonatal Medicine 2025;32(1):30-38
Purpose:
Congenital hypothyroidism (CH) is a major preventable cause of intellectual disability, particularly in very low birth weight (VLBW) infants, who are at increased risk due to hypothalamic-pituitary-thyroid axis immaturity. Early differentiation between transient CH (TCH) and permanent CH (PCH) is crucial to optimize L-thyroxine (LT4) treatment duration. This study aimed to determine the incidence of PCH among Korean VLBW infants and to identify clinical factors that may aid in distinguishing TCH from PCH.
Methods:
This retrospective cohort study included VLBW infants diagnosed with CH and treated with LT4 at a single tertiary neonatal intensive care unit between 2011 and 2020. Infants requiring LT4 beyond 3 years were classified as PCH, while those who discontinued earlier were considered TCH. Clinical characteristics, neonatal morbidities, and thyroid-related parameters were compared between the groups.
Results:
Among 1,292 VLBW infants, 122 (9.4%) were diagnosed with CH. After excluding deaths and those lost to follow-up, 73 infants were included in the final analysis (TCH, n=50; PCH, n=23). The PCH group had a significantly higher mean gestational age and greater LT4 requirements at both 12 and 36 months of age. Major anomalies were more frequently observed in PCH infants, including congenital heart defects. In multivariate analysis, higher gestational age, the presence of major anomalies, screening thyroid-stimulating hormone (TSH) >10 μIU/mL, and higher LT4 dose at 36 months were significantly associated with PCH.
Conclusion
The incidence of PCH in Korean VLBW infants was relatively higher than that reported in previous studies studies. Screening TSH level and LT4 dose requirements may support individualized follow-up and help distinguish PCH from TCH.

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