Eun Kang - Academia.edu (original) (raw)

Papers by Eun Kang

QJM: An International Journal of Medicine, Nov 19, 2009

Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease, characterized by chronic... more Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease, characterized by chronic, erosive polyarthritis and by the presence of various autoantibodies in serum and synovial fluid. Since rheumatoid factor (RF) was first described, a number of other autoantibodies have been discovered in RA patients. The autoantigens recognized by these autoantibodies include cartilage components, chaperones, enzymes, nuclear proteins and citrullinated proteins. However, the clinical significances and pathogenic roles of these antibodies are largely unknown except for RF and anticitrullinated protein antibodies (ACPAs), whose clinical usefulness has been acknowledged due to their acceptable sensitivities and specificities, and prognostic values. This review presents and discusses the current state of the art regarding RF and ACPA in RA.

Arthritis Research & Therapy

Background To compare infectious risk between JAK inhibitors (JAKis) versus TNF inhibitors (TNFis... more Background To compare infectious risk between JAK inhibitors (JAKis) versus TNF inhibitors (TNFis) among rheumatoid arthritis (RA) patients in Korea. Methods Using 2009–2019 Korea National Health Insurance Service database, we conducted a cohort study on RA patients initiating a JAKi or TNFi. The primary outcomes were herpes zoster (HZ), serious bacterial (SBI), and opportunistic infections (OI). Propensity-score fine-stratification (PSS) and weighting were applied to adjust for > 70 baseline covariates. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazard models comparing JAKi versus TNFi users. Results We included 2963 JAKi initiators PSS-weighted on 5169 TNFi initiators. During a follow-up of 1.16 years, the most frequent type of infections was HZ with incidence rate (IR) per 100 person-years of 11.54 and 4.88 in JAKi and TNFi users, respectively. The IR of SBI was 1.39 and 1.32, respectively. The OI was rare with a majority being...

Rheumatology, 2019

Objective To compare cardiovascular (CV) risk among gout patients initiating allopurinol vs febux... more Objective To compare cardiovascular (CV) risk among gout patients initiating allopurinol vs febuxostat. Methods Using 2002–2015 Korean National Health Insurance Service data for the entire Korean population, we conducted a cohort study on gout patients initiating allopurinol or febuxostat. The primary outcome was a composite CV end point of myocardial infarction, stroke/transient ischaemic attack, or coronary revascularization. Secondary outcomes were individual components of the primary outcome, and all-cause mortality. We used propensity score-matching with a 4:1 ratio for allopurinol and febuxostat initiators to control for confounding. Competing risk analyses were done for non-fatal outcomes accounting for deaths. Results We included 39 640 allopurinol initiators propensity score-matched on 9910 febuxostat initiators. The mean age was 59.1 years and 78.4% were male. The incidence rate per 100 person-years for the primary outcome was 1.89 for allopurinol and 1.84 for febuxostat i...

Arthritis Research & Therapy, 2010

Introduction: Adiponectin has been implicated in the pathogenesis of osteoarthritis (OA). We stud... more Introduction: Adiponectin has been implicated in the pathogenesis of osteoarthritis (OA). We studied the effects of adiponectin on the OA cartilage homeostasis. Methods: Immunohistochemical analysis was performed to evaluate differential expression of adiponectin receptors (AdipoRs) in nonlesional and lesional areas of OA cartilage. Cartilage and chondrocytes from the knee joints of primary OA patients were cultured in the presence of adiponectin (0~30 μg/ml). The levels of total nitric oxide (NO), matrix metalloproteinase (MMP)-1,-3, and-13, and tissue inhibitor of metalloproteinase (TIMP)-1 were measured in the conditioned media. The levels of inducible NO synthase (iNOS) and MMPs were determined with the quantitative real-time reverse transcription-polymerase chain reaction. The concentrations of collagenasecleaved type II collagen neoepitope (C1-2C) were determined in the supernatant of adiponectin-stimulated OA cartilage explants. The effects of kinase and NOS inhibitors were evaluated in the adiponectin-stimulated chondrocytes. Results: The expression levels of both AdipoR1 and AdipoR2 were significantly higher in lesional than in nonlesional areas of OA cartilage. The increased rate of AdipoR1-positive chondrocytes was twice that of AdipoR2positive chondrocytes when compared between nonlesional and lesional areas. Adiponectin-stimulated OA chondrocytes showed increased total NO and MMP-1,-3, and-13 levels compared with nonstimulated cells. The TIMP-1 level was not affected. The C1-2C levels were increased by adiponectin in OA cartilage explant culture. AMP-activated protein kinase (AMPK) and c-Jun N-terminal kinase (JNK) inhibitors (compound C and SP600125) significantly suppressed adiponectin-induced production of total NO and MMP-1,-3, and-13. Inducible NOS inhibitors enhanced the expression of the adiponectin-induced MMPs. Conclusions: Adiponectin causes matrix degradation in OA cartilage and increases MMPs and iNOS expression via the AMPK and JNK pathways in human OA chondrocytes. The catabolic effects of adiponectin may be counteracted by NO.

Journal of Rheumatic Diseases, 2020

The use of magnetic resonance imaging (MRI) and positron emission tomography (PET) in rheumatolog... more The use of magnetic resonance imaging (MRI) and positron emission tomography (PET) in rheumatology allows a better understanding of the pathophysiology of the disease as well as early diagnosis and appropriate evaluation of the disease status and treatment responses. Despite the limited availability because of the high cost, there is growing evidence for the advantages and clinical application of these modalities to various rheumatic diseases. This review discusses the basic mechanisms and clinical applications of MRI and PET in certain rheumatic diseases, including rheumatoid arthritis, axial spondyloarthritis, idiopathic inflammatory myopathies, large vessel vasculitis, central nervous system disease associated with rheumatic diseases, polymyalgia rheumatica, adult-onset Still's disease, and immunoglobulin G4-related disease.

Journal of Korean Medical Science, 2019

Beyond gouty arthritis, hyperuricemia has been associated with increased risk of renal impairment... more Beyond gouty arthritis, hyperuricemia has been associated with increased risk of renal impairments 1 and cardiovascular (CV) events. 2,3 Despite robust epidemiologic evidence linking hyperuricemia and CV risk, the underlying mechanism has been unclear. Park et al. 4 observed a significant correlation of serum homocysteine levels with carotid intima-media thickness or renal impairments among hyperuricemic patients. The finding is not surprising based on the previous report that both metabolic syndrome and renal impairments are associated with homocysteinemia. 5 Based on their results, the authors proposed a hypothesis where hyperuricemia induces homocysteinemia through renal impairments, which ultimately leads to atherosclerosis. 4 However, appropriate mediation analysis to support the hypothesis is not sufficient by the cross-sectional study design. Further studies are required to fully illuminate the underlying mechanisms between hyperuricemia and CV risk.

European Heart Journal, 2021

Aims With the high prevalence of gout and associated cardiovascular (CV) diseases, information o... more Aims With the high prevalence of gout and associated cardiovascular (CV) diseases, information on the comparative CV safety of individual urate-lowering drugs becomes increasingly important. However, few studies examined the CV risk of uricosuric agents. We compared CV risk among patients with gout who initiated allopurinol vs. benzbromarone. Methods and results Using the Korean National Health Insurance claims data (2002–17), we conducted a cohort study of 124 434 gout patients who initiated either allopurinol (n = 103 695) or benzbromarone (n = 20 739), matched on propensity score at a 5:1 ratio. The primary outcome was a composite CV endpoint of myocardial infarction, stroke/transient ischaemic attack, or coronary revascularization. To account for competing risk of death, we used cause-specific hazard models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the outcomes comparing allopurinol initiators with benzbromarone. Over a mean follow-up of 1.16 years...

Journal of Clinical Medicine, 2021

We aimed to validate quantitative high-resolution computed tomography (HRCT) imaging analyses of ... more We aimed to validate quantitative high-resolution computed tomography (HRCT) imaging analyses of interstitial lung disease (ILD) in rheumatoid arthritis (RA) patients, and to delineate a broad spectrum of annual longitudinal changes of ILD severity in the RA-ILD cohorts. Retrospective cohort 1 (n = 26) had matched PFT results and prospective cohort 2 (n = 34) were followed for over two years with baseline serum specimen. Automated quantitative analysis of HRCT was expressed as the extent of ground-glass opacity, lung fibrosis, honeycombing, and their summation—the total extent of quantitative ILD (QILD). Higher QILD score was associated with lower pulmonary function especially for DLCO% (ρ = −0.433, p = 0.027). Higher serum level of Krebs von den Lungen 6 were significantly associated with high QILD scores (ρ = 0.400, p = 0.026). Regarding QILD score changes in whole lung, even a single point increase was significantly associated with interval progression detected by the radiologist...

Marine Drugs, 2021

Fucoxanthin (FX), a natural carotenoid present in edible brown seaweed, is known for its therapeu... more Fucoxanthin (FX), a natural carotenoid present in edible brown seaweed, is known for its therapeutic potential in various diseases, including bone disease. However, its underlying regulatory mechanisms in osteoclastogenesis remain unclear. In this study, we investigated the effect of FX on osteoclast differentiation and its regulatory signaling pathway. In vitro studies were performed using osteoclast-like RAW264.7 cells stimulated with the soluble receptor activator of nuclear factor-κB ligand or tumor necrosis factor-alpha/interleukin-6. FX treatment significantly inhibited osteoclast differentiation and bone resorption ability, and downregulated the expression of osteoclast-specific markers such as nuclear factor of activated T cells 1, dendritic cell-specific seven transmembrane protein, and matrix metallopeptidase 9. Intracellular signaling pathway analysis revealed that FX specifically decreased the activation of the extracellular signal-regulated kinase and p38 kinase, and in...

Arthritis Research & Therapy, 2019

Background: Biomarkers have been actively investigated to supplement functional and imaging modal... more Background: Biomarkers have been actively investigated to supplement functional and imaging modalities to predict the severity, therapeutic responsiveness, and progression of connective tissue disease-associated interstitial lung disease (CTD-ILD). This study aimed to evaluate Krebs von den Lungen 6 (KL-6) as a potential biomarker reflecting the severity of CTD-ILD as assessed through computed tomography (CT) and pulmonary function test (PFT) parameters. Methods: This retrospective study included 549 Korean patients with rheumatoid arthritis, systemic sclerosis, inflammatory myositis, and other CTDs with or without concurrent ILD. Serum KL-6 concentration (U/mL) was measured using the latex-enhanced immunoturbidimetric assay method. CT and PFT results were collected within 1 year of serum collection. A semiquantitative grade of ILD extent was evaluated through CT scan (grade 1, 0-25%; grade 2, 26-50%; grade 3, 51-75%; grade 4, 76-100%). Results: CTD-ILD patients (n = 165) had elevated serum KL-6 levels compared to CTD patients without ILD (n = 384) (p < 0.001), and those findings were preserved after adjusting for age, sex, and CTD type. The semiquantitative grade of ILD on CT scan was significantly proportional to the KL-6 level, and the optimal cutoff KL-6 value effectively differentiated each ILD grade. The percent diffusing capacity of the lung for carbon monoxide (DLCO) (p < 0.001) and forced vital capacity (FVC) (p < 0.001) parameters had a moderate, negative correlation with the KL-6 level. Conclusion: Serum KL-6 levels were increased in CTD-ILD patients and had a positive correlation with CT grade and a negative correlation with FVC and DLCO. Serum KL-6 levels may reflect CTD-ILD severity.

Archives of rheumatology, 2017

Neuromyelitis optica is an idiopathic inflammatory demyelinating disease of the central nervous s... more Neuromyelitis optica is an idiopathic inflammatory demyelinating disease of the central nervous system (CNS) that predominantly affects the optic nerves and spinal cord. With the discovery of the pathogenic anti-aquaporin-4 (AQP4) antibody, the disease was recognized as part of a spectrum of autoimmune diseases that target AQP4, collectively referred to as neuromyelitis optica spectrum disorder (NMOSD). NMOSD consists of conditions that affect various parts of the CNS with the AQP4 antibody. In this article, we report a 43-year-old female patient who was initially diagnosed with primary Sjögren's syndrome (pSS) with CNS involvement, but was later diagnosed with overlapping pSS and NMOSD, which required more intensive treatment. The patient presented with fever, headache, dysarthria, and left-side weakness, and brain imaging showed a mass-like edematous lesion in the right frontoparietal region. She also complained of xerostomia and was diagnosed with pSS by salivary scintigraphy...

Arthritis & rheumatology (Hoboken, N.J.), Jan 8, 2018

To investigate the impact tumour necrosis factor inhibitor (TNFi) treatment and inflammation cont... more To investigate the impact tumour necrosis factor inhibitor (TNFi) treatment and inflammation control on radiographic progression in early ankylosing spondylitis (AS) over 4 years. In total, 215 early AS patients (symptom duration < 10 years) treated with TNFi (TNFi group, n = 135) or nonsteroidal anti-inflammatory drugs (NSAIDs) (control group, n = 80) were included. Two blinded readers assessed radiographic progression using modified Stoke Ankylosing Spondylitis Spine Scores (mSASSS). Inflammation control was inferred from time-averaged C-reactive protein (CRP) between two radiological assessments. Linear mixed modelling was used to estimate mSASSS changes over radiographic intervals and the impact of clinical factors on outcomes. The TNFi group had longer disease duration and higher baseline CRP and BASDAI than controls. Time-averaged CRP over radiographic intervals was lower with TNFi (0.27 ± 0.30 versus 0.61 ± 0.68 mg/dL, p < 0.001). Overall, mean (SD) mSASSS change over t...

Circulation, Jan 13, 2018

Editorial, see p 1127 BACKGROUND: Hyperuricemia and gout are associated with an increased risk of... more Editorial, see p 1127 BACKGROUND: Hyperuricemia and gout are associated with an increased risk of cardiovascular disease. Xanthine oxidase inhibitors, allopurinol and febuxostat, are the mainstay of urate-lowering treatment for gout and may have different effects on cardiovascular risk in patients with gout. METHODS: Using US Medicare claims data (2008-2013), we conducted a cohort study for comparative cardiovascular safety of initiating febuxostat versus allopurinol among patients with gout ≥65 years of age. The primary outcome was a composite end point of hospitalization for myocardial infarction or stroke. Secondary outcomes were individual end points of hospitalization for myocardial infarction, stroke, coronary revascularization, new and recurrent heart failure, and all-cause mortality. We used propensity score matching with a ratio of 1:3 to control for confounding. We estimated incidence rates and hazard ratios for primary and secondary outcomes in the propensity score-matched cohorts of febuxostat and allopurinol initiators. RESULTS: We included 24 936 febuxostat initiators propensity score-matched to 74 808 allopurinol initiators. The median age was 76 years, 52% were male, and 12% had cardiovascular disease at baseline. The incidence rate per 100 person-years for the primary outcome was 3.43 in febuxostat and 3.36 in allopurinol initiators. The hazard ratio for the primary outcome was 1.01 (95% CI, 0.94-1.08) in the febuxostat group compared with the allopurinol group. Risk of secondary outcomes including all-cause mortality was similar in both groups, except for a modestly decreased risk of heart failure exacerbation (hazard ratio, 0.94; 95% CI, 0.91-0.99) in febuxostat initiators. The hazard ratio for all-cause mortality associated with long-term use of febuxostat (>3 years) was 1.25 (95% CI, 0.56-2.80) versus allopurinol. Subgroup and sensitivity analyses consistently showed similar cardiovascular risk in both groups. CONCLUSIONS: Among a cohort of 99 744 older Medicare patients with gout, overall there was no difference in the risk of myocardial infarction, stroke, new-onset heart failure, coronary revascularization, or all-cause mortality between patients initiating febuxostat compared with allopurinol. However, there seemed to be a trend toward an increased, albeit not statistically significant, risk for all-cause mortality in patients who used febuxostat for >3 years versus allopurinol for >3 years. The risk of heart failure exacerbation was slightly lower in febuxostat initiators.

The Korean journal of internal medicine, Jan 20, 2018

This study aimed to investigate the inf luence of poor sleep quality on clinical features of prim... more This study aimed to investigate the inf luence of poor sleep quality on clinical features of primary Sjögren's syndrome (pSS). Sleep quality was cross-sectionally assessed using the Pittsburgh Sleep Quality Index (PSQI), and demographic, clinical, and laboratory data were collected from 115 Korean patients with pSS. The patients completed questionnaires on the European League Against Rheumatism (EULAR) SS Patient Reported Index (ESSPRI), quality of life (EuroQOL five dimensions questionnaire [EQ-5D]), fatigue (fatigue severity score [FSS]), and depression (Beck Depression Inventory [BDI] II]). Symptoms and patient global assessment (PGA) were evaluated with a 100-mm visual analogue scale (VAS). The EULAR sicca score (ESS), ESSPRI, and EULAR SS Disease Activity Index (ESSDAI) were calculated at study enrollment. Fifty-three patients (46.1%) had poor sleep quality and 32.4% of 71 patients without depression were poor sleepers. Poor sleepers had a significantly lower EQ-5D or ESSDA...

Journal of the American Heart Association, Jan 24, 2018

We examined the cardiovascular risk of abatacept compared with tumor necrosis factor (TNF) inhibi... more We examined the cardiovascular risk of abatacept compared with tumor necrosis factor (TNF) inhibitors in patients with rheumatoid arthritis with and without diabetes mellitus (DM). We conducted a cohort study of patients with rheumatoid arthritis who newly started abatacept or TNF inhibitors using claims data from Medicare and MarketScan. The primary outcome was a composite cardiovascular end point of myocardial infarction (MI), stroke/transient ischemic attack, and coronary revascularization. To account for >60 baseline characteristics, abatacept initiators were 1:1 propensity score (PS) matched to TNF initiators in each database. Cox proportional hazards models estimated hazard ratio (HR) and 95% confidence interval (CI) in the PS-matched cohort per database. A fixed-effects meta-analysis pooled database-specific HRs. We included a total of 13 039 PS-matched pairs of abatacept and TNF inhibitor initiators (6103 pairs in Medicare and 6936 pairs in MarketScan). A total of 34.7% i...

Journal of the American College of Cardiology, Jan 6, 2018

Patients with gout are at an increased risk of cardiovascular (CV) disease including myocardial i... more Patients with gout are at an increased risk of cardiovascular (CV) disease including myocardial infarction (MI), stroke, and heart failure (HF). The authors conducted a cohort study to examine comparative CV safety of the 2 gout treatments-probenecid and allopurinol-in patients with gout. Among gout patients ≥65 years of age and enrolled in Medicare (2008 to 2013), those who initiated probenecid or allopurinol were identified. The primary outcome was a composite CV endpoint of hospitalization for MI or stroke. MI, stroke, coronary revascularization, HF, and mortality were assessed separately as secondary outcomes. The authors estimated the incidence rate and hazard ratio of the primary and secondary outcomes in the 1:3 propensity score-matched cohort of probenecid and allopurinol initiators. A total of 9,722 probenecid initiators propensity score-matched to 29,166 allopurinol initiators with mean age of 76 ± 7 years, and 54% males were included. The incidence rate of the primary com...

PloS one, 2018

Recent studies have suggested that neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein-to... more Recent studies have suggested that neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein-to-albumin ratio (CAR) are emerging markers of disease activity and prognosis in patients with chronic inflammatory diseases, cardiovascular diseases, or malignancies. Therefore, we investigated the clinical significance and prognostic value of the NLR and CAR in adult patients with polymyositis and dermatomyositis. The medical records of 197 patients with newly diagnosed polymyositis/dermatomyositis between August 2003 and November 2016 were retrospectively reviewed. Survival and causes of death were recorded during an average 33-month observational period. Clinical and laboratory findings were compared between survivors and non-survivors. Using receiver operating characteristic curves, the NLR and CAR cut-off values for predicting survival were calculated. Univariate and multivariate analyses using Cox proportional hazard models were performed to identify factors associated with survival...

Scientific reports, Jan 7, 2017

The objective of this study was to investigate CXC chemokines and its receptor in patients with B... more The objective of this study was to investigate CXC chemokines and its receptor in patients with Behcet's disease (BD) and their associations with disease activity. Blood samples were collected from 109 BD patients and 36 age- and sex-matched healthy controls (HCs). Twenty-two follow-up blood samples were collected in BD patients. Serum CXC chemokines (CXCL1, CXCL8, CXCL9, CXCL10, CXCL12, CXCL13 and CXCL16) and cell surface marker expression (CD3, CD4 and CXCR3) in peripheral blood mononuclear cells (PBMCs) were assayed. Clinical features including disease activity were evaluated at the time of blood collection. CXCR3 expression in skin and intestinal lesions from BD patients and HCs was assessed via immunohistochemistry. Serum CXCL10 levels were correlated with disease activity in terms of Behçet's Disease Current Activity Form (BDCAF) (p < 0.001). In follow-up BD patients, changes in serum CXCL10 levels tended to be correlated with those of BDCAF. The percentage of CXCR3...

Arthritis research & therapy, Jan 10, 2017

Behçet's disease (BD) susceptibility had been associated with single-nucleotide polymorphisms... more Behçet's disease (BD) susceptibility had been associated with single-nucleotide polymorphisms (SNPs) in IL23R-IL12RB2, IL10, STAT4, or ERAP1 locus in Japanese, Turkish, Chinese, and other populations, but not in a Korean genome-wide association study (GWAS). We aimed to fine-map BD risk association of these four loci using extensive imputation and additional genotyping for replication. In the discovery phase, 369 patients with BD enrolled in the previous Korean GWAS and 2000 controls retrieved from a population-based cohort of healthy Koreans were imputed for their genotypes of all SNPs in the four loci using the Asian data of the 1000 Genomes Project as reference. For genotype imputation of ERAP1 SNPs, the adjacent ERAP2 SNPs were also covered. For the 10 most significantly associated SNPs (8 imputed and 2 GWAS-genotyped), an additional 84 patients with BD and 283 healthy controls were genotyped for replication. The results from the discovery and replication phases were pooled ...

Clinical and experimental rheumatology, Jan 18, 2017

To investigate the expressions of interferon (IFN)-λs and their receptor, IL28RA, in minor saliva... more To investigate the expressions of interferon (IFN)-λs and their receptor, IL28RA, in minor salivary glands (MSG) of pSS patients and their effects on the salivary gland cells. The expressions of IFN-λs and IL28RA were evaluated in MSG by immunohistochemistry in 15 patients with pSS and in 5 patients with non-SS sicca. Poly(I:C)-induced IL-28A and IL-29 expressions were determined in immortalized human salivary gland acinar (NS-SV-AC) and ductal (NS-SV-DC) cell lines. We assessed the effect of IFN-λs on the expressions of typical interferon-inducible genes, B-cell activating factor (BAFF) and CXCL10, and the synergistic effect of IL-29 and type I or II IFN on their expressions. The serum IL-29 levels were measured in 44 patients with pSS and 22 healthy controls. IFN-λs expression was significantly higher in MSG from pSS than from non-SS sicca controls. Poly(I:C) treatment led to the induction of IL-28A and IL-29 in the salivary gland cell lines. In the NS-SV-DC cells, IFN-λ significa...