Effect of recombinant human bone morphogenetic protein-2 and osteoprotegerin-Fc in MC3T3-E1 cells

Objective

We compared the osteoblastogenesis by serially administrating recombinant human bone morphogenetic protein-2 (rhBMP-2) and osteoprotegerin-immunoglobulin Fc segment complex (OPG-Fc).

Methods

The MC3T3-E1 preosteoblast cell line was differentiated for 1, 3, and 7 days with a treatment of OPG-Fc in 10~200 ng/mL concentration and the cell viability was evaluated by Cell Counting Kit-8 analysis. The level of differentiation from MC3T3-E1 cells to osteoblasts was determined by alkaline phosphatase activity. The level of runt domain-containing transcription factor 2 (Runx2) and osteopontin (OPN) manifestation, involved in osteoblast differentiation, was examined by real-time polymerase chain reaction and western blotting.

Results

During MC3T3-E1 cell differentiation, the differentiation level was high with 1-day treatment using 100 ng/mL OPG-Fc. The treatment with 50 ng/mL rhBMP-2 for 7 days, followed by 1-day treatment with 100 ng/mL OPG-Fc produced the highest differentiation level, which was approximately 5.3 times that of the control group (p<0.05). The expression of Runx2 mRNA significantly increased, reaching 2.5 times the level of the control group under the condition of 7-day treatment with rhBMP-2 and 1-day treatment with OPG-Fc (p<0.001). The expression of Runx2 protein significantly increased to approximately 5.7 times that of the control group under the condition of 7-day treatment with rhBMP-2, followed by 1-day treatment with OPG-Fc (p<0.01). The expression of OPN protein showed no change from that of the control group under various conditions of rhBMP-2 and OPG-Fc combinations.

Conclusion

These results imply that the treating preosteoblasts with rhBMP-2 first and then with OPG-Fc increased osteoblast differentiation efficacy.

The complement factor H-related protein-5 (CFHR5) exacerbates pathological bone formation in ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease, characterized by excessive new bone formation. We previously reported that the complement factor H-related protein-5 (CFHR5), a member of the human factor H protein family, is significantly elevated in patients with AS compared to other rheumatic diseases. However, the pathophysiological mechanism underlying new bone formation by CFHR5 is not fully understood. In this study, we revealed that CFHR5 and proinflammatory cytokines (TNF, IL-6, IL-17A, and IL-23) were elevated in the AS group compared to the HC group. Correlation analysis revealed that CFHR5 levels were not significantly associated with proinflammatory cytokines, while CFHR5 levels in AS were only positively correlated with the high CRP group. Notably, treatment with soluble CFHR5 has no effect on clinical arthritis scores and thickness at hind paw in curdlan-injected SKG, but significantly increased the ectopic bone formation at the calcaneus and tibia bones of the ankle as revealed by micro-CT image and quantification. Basal CFHR5 expression was upregulated in AS-osteoprogenitors compared to control cells. Also, treatment with CFHR5 remarkedly induced bone mineralization status of AS-osteoprogenitors during osteogenic differentiation accompanied by MMP13 expression. We provide the first evidence demonstrating that CFHR5 can exacerbate the pathological bone formation of AS. Therapeutic modulation of CFHR5 could be promising for future treatment of AS. KEY MESSAGES: Serum level of CFHR5 is elevated and positively correlated with high CRP group of AS patients. Recombinant CFHR5 protein contributes to pathological bone formation in in vivo model of AS. CFHR5 is highly expressed in AS-osteoprogenitors compared to disease control. Recombinant CFHR5 protein increased bone mineralization accompanied by MMP13 in vitro model of AS.

The statistical challenge of analysing changes in dual energy computed tomography (DECT) urate volumes in people with gout

BACKGROUND

Dual energy computed tomography (DECT) allows direct visualization of monosodium urate crystal deposition in gout. However, DECT urate volume data are often highly skewed (mostly small volumes with the remainder considerably larger), making statistical analyses challenging in longitudinal research. The aim of this study was to explore the ability of various analysis methods to normalise DECT urate volume data and determine change in DECT urate volumes over time.

METHODS

Simulated datasets containing baseline and year 1 DECT urate volumes for 100 people with gout were created from two randomised controlled trials. Five methods were used to transform the DECT urate volume data prior to analysis: log-transformation, Box-Cox transformation, log(X-(min(X)-1)) transformation; inverse hyperbolic sine transformation, and rank order. Linear regression analyses were undertaken to determine the change in DECT urate volume between baseline and year 1. Cohen's d were calculated as a measure of effect size for each data treatment method. These analyses were then tested in a validation clinical trial dataset containing baseline and year 1 DECT urate volumes from 91 people with gout.

RESULTS

No data treatment method successfully normalised the distribution of DECT urate volumes. For both simulated and validation data sets, significant reductions in DECT urate volumes were observed between baseline and Year 1 across all data treatment methods and there were no significant differences in Cohen's d effect sizes.

CONCLUSIONS

Normalising highly skewed DECT urate volume data is challenging. Adopting commonly used transformation techniques may not significantly improve the ability to determine differences in measures of central tendency when comparing the change in DECT urate volumes over time.

Factors for achieving target serum uric acid levels after initiating urate-lowering therapy in patients with gout: results from the ULTRA registry

Achieving target serum uric acid (SUA) levels is important in gout management. Guidelines recommend lowering SUA levels to < 6 mg/dL; however, many patients fail to reach this target, even with uric acid-lowering therapy (ULT). This study investigated clinical characteristics of target SUA achievers among Korean patients with gout. This study used data from the ULTRA registry, a nationwide inception cohort established in September 2021 that enrolls patients with gout who initiate ULT. Demographic, clinical, and laboratory data were collected at baseline; the 6-month follow-up. Patients were divided into two groups: target achievers (SUA level < 6 mg/dL at 6 months) and non-achievers. The mean participant (N = 117) age was 56.1 years, and 88.0% were male. At 6 months, 83 patients (70.9%) reached target SUA levels. Target achievers had better drug adherence (≥ 80%) to ULT (97.6% vs. 76.5%; p < 0.01) than non-achievers. Target non-achievers had a higher percentage of a family history of gout (32.4% vs. 10.8%; p < 0.01) and less antihypertensive agent use (38.2% vs. 59.0%; p = 0.03) than target achievers. Multivariate regression analysis revealed that good adherence to ULT, the absence of a family history of gout, and antihypertensive agent use were key factors associated with achieving target SUA levels at 6 months.

Grape seed proanthocyanidin extract induces apoptotic and autophagic cell death in rheumatoid arthritis fibroblast-like synoviocytes

Objectives

In this study, we aimed to evaluate the association between grape seed proanthocyanidin extract (GSPE) and rheumatoid arthritis-fibroblast-like synoviocytes (RA-FLSs) and to investigate whether GSPE induces cell death in RA-FLSs.

Materials and methods

The FLSs were isolated from RA synovial tissues. Cell viability and cell cycle staging were analyzed using a hemocytometer and flow cytometry. Caspase 3 and poly (ADP-ribose) polymerase (PARP) proteins were analyzed using Western blotting with z-VAD-fmk. Protein LC3 and polyubiquitin-binding protein p62 that were degraded by autophagy were evaluated using Western blotting with 3-methyladenine and chloroquine. Reactive oxygen species (ROS) were also evaluated.

Results

When RA-FLSs were treated with GSPE, cell viability decreased, the number of cells in sub-G1 and G2/M phases increased, and the expression of pro-PARP and pro-caspase 3 proteins decreased in a concentration-dependent manner. This result was offset, when the cells were co-treated with the pan-caspase inhibitor z-VAD-fmk. The reduced cell viability, increased expression of LC3-II protein, and reduced expression of p62 protein with GSPE treatment were offset, when RA-FLSs were co-treated with GSPE and autophagy inhibitors 3-methyladenine and chloroquine. The level of ROS in RA-FLSs treated with GSPE was significantly lower than treatment with N-acetyl-cysteine, a ROS inhibitor.

Conclusion

Our study results show that GSPE induces apoptotic and autophagic cell death and inhibites reactive oxygen species in RA-FLSs.

Development of a radiographic scoring system for new bone formation in gout

Background

Features of new bone formation (NBF) are common in tophaceous gout. The aim of this project was to develop a plain radiographic scoring system for NBF in gout.

Methods

Informed by a literature review, scoring systems were tested in 80 individual 1st and 5th metatarsophalangeal joints. Plain radiography scores were compared with computed tomography (CT) measurements of the same joints. The best-performing scoring system was then tested in paired sets of hand and foot radiographs obtained over 2 years from an additional 25 patients. Inter-reader reproducibility was assessed using intraclass correlation coefficients (ICC). NBF scores were correlated with plain radiographic erosion scores (using the gout-modified Sharp-van der Heijde system).

Results

Following a series of structured reviews of plain radiographs and scoring exercises, a semi-quantitative scoring system for sclerosis and spur was developed. In the individual joint analysis, the inter-observer ICC (95% CI) was 0.84 (0.76–0.89) for sclerosis and 0.81 (0.72–0.87) for spur. Plain radiographic sclerosis and spur scores correlated with CT measurements (r = 0.65–0.74, P < 0.001 for all analyses). For the hand and foot radiograph sets, the inter-observer ICC (95% CI) was 0.94 (0.90–0.98) for sclerosis score and 0.76 (0.65–0.84) for spur score. Sclerosis and spur scores correlated highly with plain radiographic erosion scores (r = 0.87 and 0.71 respectively), but not with change in erosion scores over 2 years (r = −0.04–0.15).

Conclusion

A semi-quantitative plain radiographic scoring method for the assessment of NBF in gout is feasible, valid, and reproducible. This method may facilitate consistent measurement of NBF in gout.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02683-9.

Pharmacotherapy for gout

Background: Gout is a common disease that is mainly caused by hyperuricemia. Although it is relatively easy to treat, adherence to drug treatment and the rate at which treatment targets are met is low.Current Concepts: For the treatment of acute gout attack, colchicine, nonsteroidal anti-inflammatory drugs, and glucocorticoids can be used alone or in combination depending on the severity of symptoms. To prevent gout attacks, patients are started on colchicine prior to or concurrent with treatment with uric acid–lowering drugs. The treatment is maintained until serum uric acid levels have returned to normal, and the patient has had no acute attacks for three to six months. Ultimately, the symptoms of gout are controlled in the long term by treating the patient’s hyperuricemia. For this purpose, allopurinol, febuxostat, and benzbromarone are used, and the side effects and contraindications for each drug should be checked. The goal for the treatment of chronic gout is to maintain a serum uric acid concentration below 6.0 mg/dL.Discussion and Conclusion: Patients visit the emergency departments of hospitals for sudden gout attacks. However, gout is a chronic disease that requires the lifelong use of uric acid–lowering agents. Therefore, it is necessary to educate patients on a serum urate-based treat-to-target approach.

J-shaped Relationship Between Chronic Kidney Disease and Serum Uric Acid Levels: A Cross-sectional Study on the Korean Population

Objective

Both hypouricemia and hyperuricemia are reportedly associated with reduced kidney function This study investigated the association between uric acid levels and the risk of reduced renal function in men and women.

Methods

We conducted a cross-sectional study using data from a government-funded health examinee cohort of a Korean genome and epidemiological study A total of 172,970 participants (58,981 men, 113,989 women) aged 40∼79 years were included A logistic regression test was performed, and the odds ratio (OR) and 95% confidence interval (CI) were calculated to examine the relationship between stratified uric acid levels and the frequency of chronic kidney disease.

Results

As the uric acid level increased, the risk of reduced renal function increased Moreover, for uric acid levels ≤20 mg/dL, the risk of reduced renal function was higher than that of the reference group Among the total, man, and woman groups, a statistically significant association was observed in men (OR 171, 95% CI 0945∼3111, OR 5003, 95% CI 1405∼17809, and OR 1377, 95% CI 0696∼2724, respectively).

Conclusion

The OR of reduced renal function according to uric acid levels formed a J-shaped curve in both genders.

Serial administration of rhBMP-2 and alendronate enhances the differentiation of osteoblasts

AIM

The incorporation of growth factors is an effective strategy to accelerate bone induction. Bone morphogenetic protein-2 (BMP-2) promotes osteoblast differentiation and induces bone formation. Alendronate (ALN) is an osteoclast deactivation drug. We investigated the effect of serial administration of recombinant human BMP-2 (rhBMP-2) and ALN on osteoblast differentiation.

METHODS

The effect of serial administration of rhBMP-2 (0-150 ng/mL) and ALN (0-15 µmol/L) on the viability and differentiation of a clonal murine calvarial cell line, MC3T3-E1, was evaluated at various concentrations and for different periods. The Cell Counting Kit-8 assay was used to assess cell viability. The alkaline phosphatase activity was evaluated as an indicator of osteogenic differentiation. The expression levels of runt domain-containing transcription factor 2 (Runx2) and osteopontin (OPN) were analyzed by real-time polymerase chain reaction and western blotting. Statistical analyses were performed using Student's t test.

RESULTS

The serial treatment with rhBMP-2 and ALN increased the expression of the differentiation-related factors Runx2 and OPN, as well as the differentiation ability of osteoblasts compared with individual or simultaneous treatment. The osteoblasts treated with rhBMP-2 followed by ALN showed the highest differentiation. The degree of differentiation in the group treated with rhBMP-2 for 7 days followed by ALN for 3 days was increased by 1.5 times compared with that of the group treated with rhBMP-2 alone (P < .01).

CONCLUSION

These findings indicate that the serial administration of rhBMP-2 and ALN may exert osteogenic effects on osteoblastic cells via the upregulation of Runx2 and OPN.

Bath Ankylosing Spondylitis Disease Activity Index is Associated With the Quality of Sleep in Ankylosing Spondylitis Patients

Objective

High disease activity of ankylosing spondylitis (AS) is associated with poor sleep quality The purpose of this study was to identify which of the representative tools for evaluating the disease activity of AS best reflect the quality of sleep

Methods

A total of 107 AS patients were enrolled in the study and the sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) Age, sex, concomitant medication, erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP) level, Beck Depression Inventory second edition (BDI-II), Bath ankylosing spondylitis disease activity index (BASDAI), ankylosing spondylitis disease activity score (ASDAS)-ESR, ASDAS-CRP, pain visual analog scale, Insomnia Severity Index (ISI), and Epworth Sleepiness Scale (ESS) were analyzed as covariates

Results

Overall, 65% (70/107) of subjects reported poor sleep quality (PSQI>5) There was a positive correlation between the sleep quality and disease activity as measured by the BASDAI, ASDAS-ESR, and ASDAS-CRP In addition, the BASDAI demonstrated good correlations with ISI, ESS, and BDI-II, respectively However, only BASDAI showed reliable correlation with PSQI among the disease activity parameters of AS (adjusted odd ratio 5.36, p=0.023)

Conclusion

BASDAI is the most reliable parameter of disease activity associated with the sleep quality in patients with AS

Distribution of serum uric acid levels and prevalence of hyper- and hypouricemia in a Korean general population of 172,970

BACKGROUND/AIMS

We investigated the distribution of serum uric acid (SUA) levels and estimated the prevalence of hyperuricemia and hypouricemia in the Korean population.

METHODS

This cross-sectional study used data from the Korean Genome and Epidemiology Study and included 172,970 participants (58,981 men and 113,989 women) aged 40 to 79 years. Hypouricemia and hyperuricemia were defined as SUA level ≤ 2.0 mg/dL and > 7 mg/dL, respectively. The prevalence of hyperuricemia and hypouricemia was evaluated by age and sex.

RESULTS

The mean SUA levels were significantly higher in men than in women (5.71 ± 1.27 mg/dL vs. 4.21 ± 0.96 mg/dL, p < 0.001). The mean SUA levels and prevalence of hyperuricemia increased with age in women but not in men. The overall prevalence of hyperuricemia and that in men and women was 50.82, 133.25, and 8.17 per 1,000 persons, respectively; the overall prevalence of hypouricemia and that in men and women was 4.16, 1.10, and 5.75 per 1,000 persons, respectively. The prevalence of hypouricemia in men was similar across all age groups; however, that in women was the highest in the age group of 40 to 49 years and the lowest in the age group of 50 to 59 years.

CONCLUSION

The distribution of SUA levels and prevalence of hyperuricemia and hypouricemia differed according to age and sex. Age and sex should be considered in studies on uric acid-related diseases.

Renal safety and urate-lowering efficacy of febuxostat in gout patients with stage 4-5 chronic kidney disease not yet on dialysis

BACKGROUND/AIMS

The safety and efficacy of febuxostat in patients with stage 4-5 chronic kidney disease (CKD) are still unclear owing to a lack of studies in these patients. Therefore, we aimed to evaluate the effect of febuxostat on renal function, general safety, and efficacy in gout patients with stage 4-5 CKD.

METHODS

Among 739 patients who had been administered febuxostat from May 2012 to December 2016 at a single hospital in Korea, 370 patients who had been monitored for 1 year were analyzed. Serum uric acid levels and estimated glomerular filtration rate (eGFR) of patients with gouty arthritis were collected at baseline and 1 year after febuxostat administration.

RESULTS

Among the 370 patients, 280 patients were stage 1-3 CKD, 63 patients were stage 4-5 CKD, and 27 patients were on dialysis. The eGFR of 63 patients with stage 4-5 CKD, excluding dialysis patients, was 19.84 ± 7.08 mL/min/1.73 m2 when they began to take febuxostat and 23.49 ± 16.67 mL/min/1.73 m2 after 12 months (p = 0.13). The urate-lowering effect after 12 months of febuxostat medication showed statistical significance (8.96 ± 2.31 mg/dL at baseline and 4.88 ± 1.68 mg/dL after 12 months, p < 0.01). The difference in incidence of adverse events among patients with stage 1-3 CKD, those with stage 4-5 CKD, and those on dialysis was not significant.

CONCLUSION

Febuxostat demonstrated renal safety and good urate-lowering efficacy in gout patients with stage 4-5 CKD, who are not yet on dialysis.

Proteomic analysis of human synovial fluid reveals potential diagnostic biomarkers for ankylosing spondylitis

BACKGROUND

Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease affecting the axial skeleton and peripheral joints. The etiology of this disease remains poorly understood, but interactions between genetic and environmental factors have been implicated. The present study identified differentially expressed proteins in the synovial fluid (SF) of AS patients to elucidate the underlying cause of AS.

METHODS

A cohort of 40 SF samples from 10 AS and 10 each of rheumatoid arthritis (RA), gout, and osteoarthritis (OA) patients were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) to identify differentially expressed proteins specific to AS. The label-free LC-MS/MS results were verified by western blotting.

RESULTS

We identified 8 proteins that were > 1.5-fold upregulated in the SF of AS patients compared to that of the disease control groups, including HP, MMP1, MMP3, serum amyloid P-component (APCS), complement factor H-related protein 5 (CFHR5), mannose-binding lectin 2 (MBL2), complement component C9 (C9), and complement C4-A (C4A). CFHR5 and C9 were previously found in serum from AS patients, while APCS was previously found in SF as well as in serum. However, the present study has identified C4A, and MBL2 as potential AS biomarkers for the first time. The expression levels of MMP3, C9, and CFHR5 were verified in AS SF using western blotting.

CONCLUSION

We performed quantitative comparative proteomic analysis using by LC-MS/MS of the SF from four disease states: RA, gout, and OA. This systematic comparison revealed novel differentially expressed proteins in AS SF, as well as two previously reported candidate biomarkers. We further verified the expression of MMP3, C9 and CFHR5 by western blot. These proteins may serve as diagnostic or prognostic biomarkers in patients with AS, and may thus improve the clinical outcomes of this serious disease.

The association of disease activity, pro-inflammatory cytokines, and neurotrophic factors with depression in patients with rheumatoid arthritis

Inflammation and trophic factors (brain-derived neurotrophic factor [BDNF], vascular endothelial growth factor, glial cell line-derived neurotrophic factor, and insulin-like growth factor-1) are associated with depression in the general population. Rheumatoid arthritis (RA) is a chronic representative inflammatory autoimmune disease; however, the association of disease activity, pro-inflammatory cytokines, and neurotrophic factors with depression has not been sufficiently investigated. Therefore, we determined the prevalence of depression and risk factors for depression and deterioration of depressive symptoms in RA patients. In addition, we analyzed the association between disease activity, pro-inflammatory cytokines, trophic factors, and depression in RA (N = 474). Demographic and laboratory data were examined, and routine assessment of patient index data 3 (RAPID 3) and disease activity score 28-joint count C-reactive protein (DAS 28-CRP) was performed to assess disease activity of RA. Depression was measured using the Korean version of the Beck Depression Inventory-second edition (K-BDI II). A K-BDI score ≥18 was considered the cut-off for depression in accordance with a previous validation study. The serum level of pro-inflammatory cytokines and neurotrophic factors was assessed by enzyme-linked immune sorbent assay. The prevalence of depression was 32.4% in patients with RA. The severity of disease activity of RA (RAPID 3 score [OR 2.34; 95% confidence interval, CI 1.22-4.51], DAS 28-CRP [≥3.2] [OR 1.60, 95% CI 1.01-2.53]) and severity of fatigue (OR 1.26 95% CI 1.15-1.38) were associated with depression and deterioration of depressive symptoms in the multivariate analysis. Among the components of RAPID 3 and DAS 28-CRP, patient assessment for global health and abilities for daily performance were more related to depression. The level of pro-inflammatory cytokines (IL-1β, IL-6, TNF-alpha) was not related to depression. The level of BDNF was significantly lower in RA patients with depression and was negatively correlated with K-BDI II score. Depression was related with the level of fatigue, low expression of BDNF, and high RA disease activity, which was associated with impaired ability to perform activities of daily life. Strict control of fatigue and disease activity to improve one's capacity to perform daily life activities would be important to regulate depression. The level of BDNF might be one of the possible biomarkers to predict or monitor depression in patients with RA.

The relationship between anti-C-reactive protein and disease activity in patients with systemic lupus erythematosus

BACKGROUND/AIMS

Anti-C-reactive protein (CRP) antibody has been introduced as a potential biologic marker in Systemic lupus erythematosus (SLE). The aim of study is to evaluate the level of anti-CRP antibody in patients with SLE.

METHODS

This study investigated the relationship between levels of anti-CRP antibodies and disease activity markers, such as complement, anti-double-stranded DNA antibody, and SLE disease activity index in 34 patients with SLE.

RESULTS

The serum anti-CRP antibody levels of the patients with SLE were significantly higher than those of the healthy controls (11.3 ± 5.6 µg/mL vs. 9.1 ± 2.8 µg/mL). The percentages of the positive anti-CRP antibody were 52.9% in SLE and 27.8% in controls. Disease duration of SLE showed significant correlation with the anti-CRP antibody (r = 0.234, p = 0.026). However no significant relationship was observed between the levels of anti-CRP antibodies and disease activity markers.

CONCLUSIONS

These data show that the anti-CRP antibody levels of the patients with SLE were significantly higher than those of healthy controls. We observed that the presence of the anti-CRP anti-CRP antibody was not associated with disease activity of SLE.

Grape seed proanthocyanidin extract ameliorates murine autoimmune arthritis through regulation of TLR4/MyD88/NF-κB signaling pathway

BACKGROUND/AIMS

Grape seed proanthocyanidin extract (GSPE) has been reported to have a beneficial effect on regulating inf lammation. However, the anti-inflammatory mechanism of GSPE remains unclear. The aim of this study was to verify the influence of GSPE on the Toll-like receptor 4 (TLR4)-mediated signaling pathway in the regulation of murine autoimmune arthritis.

METHODS

Collagen-induced arthritis (CIA) was induced in dilute brown non-agouti (DBA)/1J mice. The mice were treated with GSPE (0 or 100 mg/kg) intraperitoneally. The severity of arthritis was assessed clinically, biochemically, and histologically. Immunostaining for TLR4 was performed. The expressions of TLR4 and downstream signaling molecules were analyzed by Western blot. The effect of GSPE on lipopolysaccharide (LPS)-induced TLR4 activation was also evaluated using RAW264.7 cells and fibroblast-like synoviocytes (FLSs) from patients with rheumatoid arthritis and from those with osteoarthritis.

RESULTS

GSPE attenuated the clinical severity of arthritis and decreased histological damage. GSPE treatment reduced the number of TLR4-stained cells in the synovium of mice with CIA. GSPE also downregulated the expression of TLR4, myeloid differentiation factor 88 (MyD88) and phosphorylated IκBα synovial protein in CIA mice. Concurrently, GSPE inhibited the nuclear translocation of nuclear factor-κB (NF-κB) subunits (p65 and p50). LPS-induced TLR4 activation was suppressed by GSPE in human FLS as well as in murine macrophages in vitro.

CONCLUSIONS

Our results demonstrated that GSPE ameliorated CIA by regulating the TLR4-MyD88-NF-κB signaling pathway.

Digital tomosynthesis as a new diagnostic tool for assessing of chronic gout arthritic feet and ankles: comparison of plain radiography and computed tomography

This aimed to compare the three radiographic methods of digital tomosynthesis (DT), plain radiography, and computed tomography (CT) for evaluating changes in feet of patients with chronic gouty arthritis. Two independent radiologists read the plain radiography, DT, and CT images of 30 male patients with gout. The degrees of erosion and joint space narrowing were scored using the Sharp-van der Heijde scoring method in 18 foot joints, which consisted of four proximal interphalangeal and one interphalangeal joint of the first toe, five metatarsophalangeal, five tarsometatarsal, and three naviculo-cuneiform joints of the foot. DT showed high reproducibility [0.929 for intraobserver intraclass correlation coefficient (ICC) and 0.838 for interobserver ICC]. DT showed similar results to those of CT and superior results to those of plain radiography for evaluating radiographic damage [mean total score, 8.5 ± 14.6 (±standard deviation) for plain radiography, 12.9 ± 12.4 for DT, and 12.6 ± 11.2 for CT]. This study showed that DT is a good method for evaluating radiographic changes in patients with gout. Further research is needed to apply DT to actual clinical settings.

Association of sleep quality in Behcet disease with disease activity, depression, and quality of life in Korean population

BACKGROUND/AIMS

Sleep disturbance is prime concern in patients with Behcet disease. The purpose of this study was to find out the effects of sleep quality, in Korean patients suffering from Behcet disease. We further investigated the relationship between depression, quality of life and the clinical findings of Behcet disease.

METHODS

The study was performed by the cross-sectional design. Sleep quality was assessed by the Korean version of Pittsburgh sleep quality index (PSQI). Disease activity of Behcet disease was evaluated by Behcet disease current activity form (BDCAF). Depression was assessed by the Korean version of Beck depression inventory second edition (BDI-2). Quality of life was assessed by the Korean version of the Leeds Behcet disease quality of life measure (BDQoL).

RESULTS

Among the 100 patients studied, 42% reported poor sleep quality (PSQI ≥ 9). These patients have a higher BDI-2, total BDCAF and pain visual analogue scale (VAS) score (p < 0.001, p = 0.022, and p = 0.005). Considering BDCAF, the frequency of genital ulcer was significantly higher (p = 0.01). Behcet was higher in females. The BDQoL was lower in poor sleeper group (p = 0.004 and p < 0.001). Among 7 PSQI components, daytime dysfunction was higher in patients with high disease activity (p = 0.03). Total PSQI score were strongly correlated with BDCAF, BDI-2, BDQoL, and pain VAS score (p = 0.02, p < 0.001, p < 0.001, and p < 0.001, respectively).

CONCLUSIONS

Low sleep quality is directly associated with disease activity, depression, and quality of life in Korean patients with Behcet disease.

A neurometabolite study of chronic daily headache in patients with systemic lupus erythematosus using magnetic resonance spectroscopy: comparison with fibromyalgia patients and healthy controls

BACKGROUND/AIMS

Neuropsychiatric systemic lupus erythematosus (SLE) includes a broad spectrum of neurologic and psychiatric manifestations. One of the most commonly observed neuropsychiatric symptoms is headache. However, the lack of specific clinical distinctions for headache in SLE has made it difficult to elucidate its pathophysiology. The aim of this study is to evaluate the neurometabolic changes using Proton Magnetic Resonance Spectroscopy (¹H-MRS) in patients with SLE who suffer from chronic daily headache (CDH).

METHODS

SLE and fibromyalgia patients with CDH and healthy controls were recruited (n = 9, n = 5, and n = 6, respectively). ¹H-MRS metabolite ratios were evaluated in bilateral basal ganglia (BG) and bilateral peritrigonal white matter (PWM).

RESULTS

¹H-MRS showed a significantly decreased N-acetylaspartate (NAA)/creatine (Cr) ratio in right BG in SLE patients with CDH compared to fibromyalgia patients with CDH and normal controls (p = 0.029 and p = 0.020, respectively). Left PWM NAA/Cr and choline/Cr ratios in SLE patients with CDH were lower than those in fibromyalgia patients with CDH (p = 0.019 and p = 0.029, respectively).

CONCLUSIONS

This study suggests the possibility that CDH in patients with SLE might be associated with neuronal dysfunction and neurometabolic changes.

Prevalence and possible causes of hypouricemia at a tertiary care hospital

BACKGROUND/AIMS

We aimed to investigate the prevalence and possible causes of hypouricemia in the Korean population and to compare our findings with published results of other populations.

METHODS

We examined the serum uric acid levels of 30,757 subjects who had their uric acid values measured at least once during a 1-year period. All individuals with hypouricemia (serum uric acid < 2.0 mg/dL, n = 424) were reviewed with respect to medical drug history and concomitant diseases previously identified as being associated with hypouricemia.

RESULTS

The prevalence of hypouricemia was 4.14% (299/7,223) among inpatients and 0.53% (125/23,534) among outpatients, for an overall prevalence of 1.39% (424/30,757). Possible causes associated with hypouricemia were found to be solid or hematologic malignancies (n = 86), diabetes mellitus (n = 56), and therapeutic drugs (n = 29). The medications were allopurinol (n = 11), angiotensin II receptor blockers (n = 10), salicylates (n = 6), febuxostat (n = 1), and warfarin (n = 1). In the remaining 226 individuals, the cause of hypouricemia was not identified.

CONCLUSIONS

Hypouricemia is relatively common in the Korean population compared to those of other countries. The possible causes associated with hypouricemia are related to underlying diseases and medications.

Safety of Resuming Tumor Necrosis Factor Inhibitors in Ankylosing Spondylitis Patients Concomitant with the Treatment of Active Tuberculosis: A Retrospective Nationwide Registry of the Korean Society of Spondyloarthritis Research

Backgrounds

Patients who develop an active tuberculosis infection during tumor necrosis factor (TNF) inhibitor treatment typically discontinue TNF inhibitor and receive standard anti-tuberculosis treatment. However, there is currently insufficient information on patient outcomes following resumption of TNF inhibitor treatment during ongoing anti- tuberculosis treatment. Our study was designed to investigate the safety of resuming TNF inhibitors in ankylosing spondylitis (AS) patients who developed tuberculosis as a complication of the use of TNF inhibitors.

Methods

Through the nationwide registry of the Korean Society of Spondyloarthritis Research, 3929 AS patients who were prescribed TNF inhibitors were recruited between June 2003 and June 2014 at fourteen referral hospitals. Clinical information was analyzed about the patients who experienced tuberculosis after exposure to TNF inhibitors. The clinical features of resumers and non-resumers of TNF inhibitors were compared and the outcomes of tuberculosis were surveyed individually.

Findings

Fifty-six AS patients were treated for tuberculosis associated with TNF inhibitors. Among them, 23 patients resumed TNF inhibitors, and these patients were found to be exposed to TNF inhibitors for a longer period of time and experienced more frequent disease flare-up after discontinuation of TNF inhibitors compared with those who did not resume. Fifteen patients resumed TNF inhibitors during anti-tuberculosis treatment (early resumers) and 8 after completion of anti-tuberculosis treatment (late resumers). Median time to resuming TNF inhibitor from tuberculosis was 3.3 and 9.0 months in the early and late resumers, respectively. Tuberculosis was treated successfully in all resumers and did not relapse in any of them during follow-up (median 33.8 [IQR; 20.8–66.7] months).

Conclusions

Instances of tuberculosis were treated successfully in our AS patients, even when given concomitantly with TNF inhibitors. We suggest that early resumption of TNF inhibitors in AS patients could be safe under effective coverage of tuberculosis.

Simplified Radiographic Damage Index for Affected Joints in Chronic Gouty Arthritis

The aim of this study was to develop and validate a new radiographic damage scoring method (DAmagE index of GoUt; DAEGU) in chronic gout using plain radiography. Two independent observers scored foot x-rays from 15 patients with chronic gout according to the DAEGU method and the modified Sharp/van der Heijde (SvdH) method. The 10 metatarsophalangeal (MTP) and 2 interphalangeal (IP) joints of the first toes of both feet were scored to assess the degrees of erosion and joint space narrowing (JSN). The intraobserver and interobserver reliabilities were analyzed by calculating the intraclass correlation coefficient (ICC) and minimal detectable change (MDC). The correlation between the DAEGU and SvdH methods was analyzed by calculating the Spearman's rho correlation coefficients and Kappa coefficients. The DAEGU method was found to be highly reproducible (0.945-0.987 for the intraobserver and 0.993-0.996 for the interobserver ICC values). The erosion, JSN, and total scores exhibited strong positive correlations between the DAEGU and SvdH methods and also within each method (r = 0.860-0.969, P < 0.001 for all parameters). The DAEGU and SvdH methods were in very good agreement as determined by Kappa coefficient analysis [0.732 (0.387-1.000) for erosion and 1.000 (1.000-1.000) for JSN]. In conclusion, this study revealed that DAEGU method was a reliable and feasible tool in the assessment of radiographic damage in chronic gout. The DAEGU method may provide a more easy assessment of structural damage in chronic gout in the real clinical practice.

Infliximab partially alleviates the bite force reduction in a mouse model of temporomandibular joint pain

Temporomandibular joint (TMJ) disorder is clinically important because of its prevalence, chronicity, and therapy-refractoriness of the pain. In this study, we investigated the effect of infliximab in a mouse model of TMJ pain using a specially-engineered transducer for evaluating the changes in bite force (BF). The mice were randomly divided into three groups (7 mice per group): the control group, the complete Freund's adjuvant (CFA) group, and the infliximab group. BF was measured at day 0 (baseline BF). After measuring the baseline BF, CFA or incomplete Freund's adjuvant was injected into both TMJs and then the changes in BF were measured at days 1, 3, 5, 7, 9, and 13 after the TMJ injection. For measuring the BF, we used a custom-built BF transducer. Control, CFA, and infliximab groups showed similar baseline BF at day 0. From day 1, a significant reduction in BF was observed in the CFA group, and this reduction in BF was statistically significant compared to that in the control group (P < 0.05). This reduction in BF was maintained until day 7, and BF started to recover gradually from day 9. In the infliximab group also, the reduction in BF was observed on day 1, and this reduction was maintained until day 7. However, the degree of reduction in BF was less remarkable compared to that in the CFA group. The reduction in BF caused by injection of CFA into the TMJ could be partially alleviated by the injection of anti-tumor necrosis factor alpha, infliximab.

Sleep quality in rheumatoid arthritis, and its association with disease activity in a Korean population

BACKGROUND/AIMS

The aim of this study was to compare the sleep quality between rheumatoid arthritis (RA) patients and healthy controls; and to evaluate the relationship between RA disease activity and sleep quality in Korea.

METHODS

A total of 130 RA patients and 67 age- and sex-matched healthy controls were enrolled in a comparative study of sleep quality using the Pittsburgh Sleep Quality Index (PSQI). Age, gender, concomitant medication, erythrocyte sedimentation rate, serum C-reactive protein, Beck Depression Inventory second edition (BDI-II), 28 joints disease activity score (DAS28), pain visual analog scale (VAS), and PSQI were analyzed as covariates. We also analyzed the sleep quality of RA patients according to the disease activity (DAS28 ≤ 3.2, 3.2 < DAS28 < 5.1, and DAS28 ≥ 5.1, respectively).

RESULTS

The total PSQI score and the frequency of poor sleep quality, were higher in the RA patients (5.62 ± 4.19, 38.5%) than in the control subjects (3.57 ± 2.17, 13.4%). The patients with poor sleep quality (PSQI > 5) were older and had a higher BDI-II and VAS score than the patients without sleep disturbance (PSQI ≤ 5). The score in subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbance, daytime dysfunction, total PSQI, and frequency of poor sleep quality were increased when RA activity was high.

CONCLUSIONS

Sleep disturbance was observed in RA patients (38.5%), and high RA disease activity was associated with poor sleep quality in Korea.

Follow-up testing of interferon-gamma release assays are useful in ankylosing spondylitis patients receiving anti-tumor necrosis factor alpha for latent tuberculosis infection

We evaluated the utility of follow-up interferon-gamma release assays (IGRAs) for the diagnosis of reactivation of latent tuberculosis infection (LTBI) or new tuberculosis in ankylosing spondylitis (AS) patients receiving anti-tumor necrosis factor alpha (anti-TNFα). The study participants (n=127) had a negative IGRA screening before receiving anti-TNFα and were evaluated by follow-up IGRA. We retrospectively examined data of the subjects according to age, gender, tuberculosis prophylaxis, concomitant medications, IGRA conversion and anti-TNFα, including type and treatment duration. The median duration of anti-TNFα was 21.5 months, and the median age was 35.3 yr. Of the 127 patients, IGRA conversion was found in 10 patients (7.9%). There was no significant variation between IGRA conversion rate and any risk factors except for age. IGRA conversion rate was not significantly different between AS and rheumatoid arthritis (P=0.12). IGRA conversion was observed in AS patients receiving anti-TNFα in Korea. A follow-up IGRA test can be helpful for identifying LTBI or new tuberculosis in AS patients receiving anti-TNFα.

Caspase-1 level in synovial fluid is high in patients with spondyloarthropathy but not in patients with gout

Activation of caspase-1 by NALP3 inflammasomes has been shown to be important in initiating acute gouty arthritis. The objectives of this study were to measure the levels of caspase-1 in synovial fluid in gout and various arthritides, and to elucidate the clinical significance of caspase-1 levels in synovial fluid. Caspase-1, IL-1β, IL-18, and uric acid were measured in synovial fluid from 112 patients with gout and other arthritides, such as rheumatoid arthritis, osteoarthritis, and spondyloarthropathy. Caspase-1 in synovial fluid from patients with crystal-induced arthritis, inflammatory arthritis, osteoarthritis, and spondyloarthropathy was 35.9 ± 86.7, 49.7 ± 107.7, 2.1 ± 7.0, and 152.6 ± 155.7 pg/mL, respectively. The mean level and the frequency of high levels (≥125 pg/mL) of caspase-1 in spondyloarthropathy were significantly higher than those in the other arthritides including gout. Caspase-1 was detectible in the synovial fluid of patients with the various arthritides. Contrary to our hypothesis, the caspase-1 level in the synovial fluid of patients with gout was not higher than in that of other arthritides. High levels of caspase-1 may be helpful in differentiating spondyloarthropathy from other arthritides.

Joint-specific prevalence and radiographic pattern of hand osteoarthritis in Korean

We investigated the prevalence and involvement patterns of radiographic osteoarthritis (OA) with hand symptoms among Korean people and compared the difference in prevalence of hand OA between racial groups. Hand radiographs in 299 Korean subjects (266 female, 33 male) ≥40 years of age were examined, who had hand arthralgia. The study population was comprised of 206 patients who had radiographic OA at least at one hand joint. Radiographic OA (Kellgren-Lawrence scale ≥2 grades) was evaluated for 16 joints of each hand. The most prevalent OA was in the interphalangeal joints (IP) of thumb, followed by the distal interphalangeal joints (DIP) of index finger, DIP of middle and fifth finger in the frequency of order. The involvement of metacarpophalangeal joints (MP) was relatively common in 1st-3rd MP. Hand OA in Korean was higher in the thumb IP and lower in the thumb carpometacarpal joints compared with Caucasian previously reported. Moreover, the higher OA frequency of 1st-3rd MP was not in accordance with other studies in Caucasian and other Asian populations. The patterns of radiographic hand OA were symmetric (OR 15.68), clustered by ray (OR 8.69) and row (OR 6.66). In conclusion, our study showed that thumb IP and 2nd/3rd/5th DIP should be included in the assessment of radiologic hand OA in Koreans.