Y.-Q. Mo

FRI0391 The relationship between oestrogen receptors and hyperuricemia in young female systemic lupus erythematosus patients

Background We have found that the incidence of hyperuricemia of young female systemic lupus erythematosus (SLE) patients was higher than that of healthy young women[1]. Why the high level of oestrogen didn’t show protection in uric acid (UA) level of fertile female SLE patients? There few few reports yet. Objectives To investigate the relationship between UA level and the levels of oestrogen, oestrogen receptors, antibodies to oestrogen receptors. Methods This was a cross-sectional study of 62 fertile female SLE patients that were divided into two groups including a high UA group (n=27) and a normal UA group (n=35). Serum UA levels, kidney index, SLE disease indicators and levels of oestrogen, oestrogen receptors, antibodies to oestrogen receptors were determined. Multiple linear regression analysis was applied to analyse the associations of UA levels with clinical features and levels of oestrogen, oestrogen receptors and antibodies to oestrogen receptors. Results 1. The mean ages of the two groups were (28.62±7.89) years and (28.82±8.28) years respectively, with on significantly different (t=0.096, p=0.924). There was no SLE patients manifested renal failure (CRE level higher than 120 μmol/l). All the SLE patients were at the onset of disease. 2. The mean UA levels of the high UA group and the normal UA group were (531.74±134.05) μmol/L and (238.86±61.32) μmol/L respectively, with significant difference (t=−11.48, p<0.001). 3. In the high UA group, the levels of CRE, LDL, cystatin, urine protein and were dramatically higher than those were found in the normal UA group (t=−3.617,–3.319, -2.782,–2.979, and p=0.001, 0.002, 0.007, 0.004, respectively), and oestrogen receptor β level were significantly lower than that of the normal group (t=2.138, p=0.037). The positive rate of urine blood of the high UA group were significantly higher than that of the normal UA subgroup (χ2=6.213, p=0.012). 4. Multiple linear regression analysis revealed there were significant relationships between UA level and CRE, oestrogen receptor β, and urine protein, urine blood.Abstract FRI0391 – Table 1 Independently-Associated Clinical Biomarkers with Serological UA levels in fertile SLE female patients Variable Unstandardized Coefficients Standardised Coefficients t P 95% CI B SEM CRE 1.145 0.462 0.263 2.478 0.016 0.223–2.068 oestrogen receptor β −2.758 0.933 0.239 2.299 0.033 3.132–44.38 urine protein 2.906 1.042 0.286 2.788 0.019 0.825–4.986 UBLD 56.426 28.058 0.216 2.011 0.048 0.422–112.43 Constant 177.283 42.179 4.203 0.001 93.09–216.47 Conclusions Hyperuricemia in young female SLE patients indicated the renal damage, and low level of oestrogen receptor β may contribute to hyperuricemia. Reference [1] Liu H.-J, Ma J.-D, Mo Y.-Q, et al. The study on the uric acid level of the fertile female systemic lupus erythematosus patients. Ann Rheum Dis, 2015;74(S2):1095–1096. Disclosure of Interest None declared

OP0187 Fructose-containing beverages is an independent risk factor for gout early-onset in south china

Background A trend of earlier onset of gout has been reported even though its incidence increases in a linear fashion with age until 70 years. Dietary factors have been supposed to be contributed to the early onset of gout. Objectives To investigate diet characteristics of gout and their impact on the early onset of gout. Methods Consecutive gout patients who fulfilled the 2016 ACR/EULAR classification criteria were recruited between Dec 2016 and Dec 2017 A cross-section survey on dietary factors before gout onset was conducted with semi-quantitative diet questionnaire. The questionnaire included alcohol, fructose-containing beverages, soup, animal organs, sea-foods, hotpot, tea and coffee, which impact on serum uric acid (sUA) and aren’t major macronutrient provider in Chinese dietary patterns. The patients with gout onset before age 30 years were defined as early-onset group while the others were defined as control group. Results Among 180 gout patients recruited, there were 69 (38.3%) patients in early-onset group and 111 (61.7%) in control group. Compared with control group, gout patients in early-onset group presented significantly higher level of sUA, estimated glomerular filtration rate and proportion of obesity, but lower fraction excretion of uric acid and prevalence of hypertension (table 1, p<0.05). The results of diet questionnaire showed that more patients in early-onset group consumed fructose-containing beverages≥3 times/week, but less alcohol, animal organs and tea (all p<0.05, figure 1). There were no significantly difference in the consumption of soup, seafood, hotpot and coffee. Consuming fructose-containing beverages≥3 times/week [OR 8.3 (2.5, 27.1), p<0.001], alcohol ≥1 standard unit/d [OR 0.27 (0.10, 0.80), p=0.017] and tea ≥3 times/week [OR 0.33 (0.12, 0.92), p=0.033] were associated with early-onset gout after adjusted by variables which were significantly different between early-onset group and control group (table 1).Abstract OP0187 – Table 1 Comparison of clinical characteristics between the early-onset group and control group Characteristics all patients(n=180) early-onset group (n=69) control group (n=111) P Male, n(%) 168 (93.3) 68 (98.6) 100 (90.1) 0.027 Age, years 42.5±15.5 28.3±7.2 51.4±12.4 <0.001 Age of onset, years 37.8±15.1 23.5±5.1 46.7±12.1 <0.001 Duration of gout, years 3.0 (1.0,8.0) 3.0 (2.0,5.0) 3.0 (1.0,7.0) 0.782 Family history, n (%) 63 (35.0) 29 (42.0) 34 (30.6) 0.148 Tophi, n (%) 31 (17.2) 10 (14.5) 21 (18.9) 0.544 sUA, mg/dl 9.0±2.4 9.9±2.1 8.7±2.1 <0.001 FEUA,% 3.9 (2.8,5.2) 3.2 (2.3,4.7) 4.2 (3.0,5.7) 0.002 eGFR, ml/min-1/1.73m-2 83.2±19.7 91.3±17.3 78.3±19.5 <0.001 Hypertension, n (%) 58 (32.2) 11 (15.9) 47 (42.3) <0.001 Diabetes mellitus, n (%) 26 (14.4) 7 (10.1) 19 (17.1) 0.276 Dyslipidemia, n (%) 117 (65.0) 44 (63.8) 73 (65.8) 0.873 Body mass index kg/m2 25.4±3.5 25.7±4.1 25.2±3.0 0.352 Obesity, n (%) 46 (25.6) 24 (34.8) 22 (19.8) 0.034 sUA: serum uric acid; FEUA: fraction excretion of uric acid; eGFR: estimated glomerular filtration rate. Conclusions Fructose-containing beverages may be an independent risk factor for gout early-onset in south China. Patient education should emphasise diet management. Acknowledgements The present study was supported by Guangdong Natural Science Foundation, China Grant no. 2014A030310086) to Qian-Hua Li. Disclosure of Interest None declared

THU0201 Older age, hypoalbuminaemia and renal failure might be poor prognosis factors for low dose methotrexate-induced myelosuppression in patients with rheumatoid arthritis

Background Methotrexate (MTX) serves as an anchor drug in rheumatoid arthritis (RA) and the maximal dose of MTX from EULAR recommendation is 25–30 mg/w. Small cases retrospective cohort studies reported that the mortality rate of RA patients with low dose (5–25 mg/w) MTX-induced myelosuppression was about 17–25%. However, studies of low dose MTX-induced myelosuppression are rare in Chinese RA patients. Objectives To perform a retrospective case series analysis of the characteristics and outcomes of RA patients with low dose MTX-induced myelosuppression in China. Methods RA patients hospitalized at Sun Yat-Sen Memorial Hospital from January 2001 to December 2016 were recruited. Clinical data were collected and adverse effects were recorded simultaneously. Low dose MTX-induce myelosuppression was diagnosed as white blood cell <4×109/L together with hemoglobin <130 g/L and platelet count <130×109/L after treatment of MTX without an alternative cause for pancytopenia. Data were showed as mean ± standard deviation. Results (1) There were 1137 RA patients recruited and 17 patients (1.5%) of them were hospitalized for low dose MTX-induce myelosuppression. Among these 17 patients, 53% were females, age was 68±5 years, disease duration was 12±11 years. (2) Four (23.5%) patients had dose errors, taking MTX 5–10mg daily for 24 days (range: 5–80), MTX accumulated dose was 25–200mg before myelosuppression. Mean MTX dose in the other patients (n=13, 76.5%) was 11.0±1.7 mg/w (range: 7.5 –15), course of MTX was 10±11 months (range: 0.5–48). Four (30.8%) patients manifested myelosuppression within the first month after taking MTX, and 4 (30.8%) patients had been well on a stable drug dose (7.5–12.5) for more than one year before myelosuppression, 2 patients manifested myelosuppression after adding MTX dose to 15mg/w for 2 months. (3) Fifteen (88.2%) patients had oral mucositis, eight of them had involvement of both oral mucosa and skin. Fever was noticed in 10 (58.8%) patients. Infections were recorded in 6 (35.3%) patients, manifested as pneumonia (n=4), sepsis (n=1), urinary tract infection (n=1) and skin soft tissue abscesses (n=1). Two patients experienced abdominal pain and melena. (4) Among the patients with neutropenia [n=17, mean neutrophil count: (0.74±0.76)×109/L, range: 0–1.83], 9 (52.9%) developed severe neutropenia with neutrophil counts below 0.5×109/L. Five patients developed severe thrombocytopenia (platelet count <20×109/L), and severe anemia occurred in 4 patients (hemoglobin <65g/L). Hypoalbuminemia (30.0±2.8 g/L) was noted in all patients. Glomerular filtration rate (GFR)≤30 ml/min/1.73 m2 was noted in 4 (23.5%) patients and GFR≤50 ml/min/1.73 m2 in 12 (70.6%) patients. (5) Pancytopenia recovered (n=17) after discontinuation of MTX and supplementation of folic acid (10–30mg/d). Only 3 (17.6%) patients were treated with rescue intravenous leucovorin. Thirteen (76.5%) were treated with granulocyte colony stimulating factor (G-CSF) and 7 (41.2%) required blood products. Fifteen (88.2%) required antibiotic therapy. Sixteen (94.1%) patients was recovered and discharged, only one patient die from acute brainstem infarction but not from myelosuppression. Conclusions Older age, hypoalbuminaemia and renal failure might be poor prognosis factors for low dose MTX-induce myelosuppression in RA. Disclosure of Interest None declared

THU0439 More obesity and higher serum uric acid in early-onset gout patients in south china

Background Gout incidence increases in a linear fashion with age until 70 years. It was reported that there was a trend of earlier gout onset. Few studies about clinical features of early-onset gout in China are reported. Objectives To investigate the characteristics of early-onset gout in south China. Methods Patients with primary gout were recruited between June 2012 and December 2016. Face to face interview was carried out to collect demographic information, clinical characteristics of gout and comorbid diseases. The patients with gout onset before age 30 were defined as early-onset group. The other gout patients were enrolled as control group. Results (1) Five hundred and one gout patients were recruited, including 99 (19.8%) in the early-onset group and 402 (80.2%) in the control group. The onset age of the early-onset group was 24.2±5.8 (range 14–30) and the control group was 51.7±13.9 (range 31–84). There was no significant difference of gout duration between early-onset group and control group (P<0.05, Table 1). (2) Compared with the control group, the early-onset group presented lower frequency of flare in last year, higher serum uric acid and higher proportion of sUA>10mg/dl (P<0.05, Table 1). Body mass index (BMI) and prevalence of obesity were higher in the early-onset group (P<0.05, Table 1). The early-onset group exhibited lower prevalence of hypertension, diabetic mellitus, urolithiasis and chronic kidney disease (CKD) (P<0.05, Table 1). (3) There were 20 patients (20.2%) with tophi in the early-onset group. Compared with the 79 early-onset gout patients without tophi, the patients with tophi presented higher age (39.6±8.9 VS 29.1±6.2, P<0.001), duration of gout (12.6±4.8 VS 4.5±4.8, P<0.001), number of involved joints (12.5±9.3 VS 4.3±3.7, P<0.001) and prevalence of CKD (30.0% VS 10.1%, P=0.034), and lower BMI (23.7±3.7 VS 26.6±4.1 kg/m2, P=0.004). Logistic regression demonstrated that higher disease duration [OR 1.30, 95% CI (1.15, 1.46), P<0.001] and lower BMI [OR 0.80, 95% CI (0.67, 0.96), P=0.015] were associated with tophi in the early-onset gout patients.Table 1. Comparison of variables between early-onset group and control group Early-onset group (N=99) Control group (N=402) P Age, years 30.4±8.2 57.9±13.5 <0.001 Female, % 1.0% 12.7% <0.001 Age of onset, years 24.2±5.8 51.7±13.9 <0.001 Duration of gout, years 6.2±5.8 6.2±5.6 0.953 Frequency of flare in last year 6.4±7.5 9.3±10.9 0.022 sUA, mg/dl 10.6±2.4 8.9±2.5 <0.001 >10mg/dl, % 59.6% 32.8% <0.001 No. of involved joints 5.9±6.0 5.9±5.5 0.981 Tophi, % 20.2% 26.1% 0.397 Alcohol overuse, % 35.4% 34.1% 0.811 BMI, kg/m2 26.1±4.2 24.8±3.9 0.004 Obesity, % 27.3% 15.5% 0.005 Dyslipidemia, % 51.5% 54.0% 0.666 Hypertension, % 14.1% 44.0% <0.001 DM, % 6.1% 24.6% <0.001 Urolithiasis, % 19.2% 33.6% 0.007 eGFR, ml/min/1.73m2 84.8±51.0 62.9±19.7 <0.001 CKD, % 14.1% 45.6% <0.001 sUA: serum uric acid; BMI: body mass index; DM: diabetic mellitus; eGFR: estimated glomerular filtration rate; CKD: chronic kidney disease. Conclusions Early-onset gout exhibited higher sUA and was associated with obesity but not with hypertension, diabetic mellitus and renal insufficiency. Longer disease duration and lower BMI were associated with tophi in the early-onset gout patients. Acknowledgements The present study was supported by Guangdong Natural Science Foundation, China (Grant no. 2014A030310086) to Qian-Hua Li. Disclosure of Interest None declared

FRI0023 Artesunate can inhibit migration and invasion of fibroblast-like synoviocytes via suppression of matrix metalloproteinase 9 in rheumatoid arthritis patients

Background Evidences show that antimalarial agents of artemisinin and its derivatives such as artesunate may inhibit proinflammatory cytokines secretion from human rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) in vitro. It has also been demonstrated that artesunate may ameliorate the symptoms of arthritis and prevent joint damage in collagen induced arthritis rat, which suggests that artesunate may be used for RA treatment. Recent studies show that RA-FLS is critical for joint destruction in RA because it can migrate and attach to cartilage and bone, and then invade them by secreting proteases such as matrix metalloproteinases (MMP) 9 in RA. However, effects of artesunate on migration and invasion of RA-FLS are poorly understood. Objectives To investigated the effects of artesunate on migration and invasion of RA-FLS and its underlying mechanism. Methods Synovial tissues were obtained from active RA patients as well as osteoarthritis (OA) and noninflammatory orthopedic arthropathies (Orth.A) patients and immumohistochemical (IHC) staining were performed for MMP9 expression. FLS isolated from these patients were analyzed for MMP9 exprssion by western blot (WB) and incubated with artesunate at different concentrations (0μM, 20μM, 40μM and 60μM), methotrexate (MTX, 10nM) or hydroxychloroquine (HCQ, 20μM) for 24 hours. Effects of artesunate on migration and invasion capacity were detected by transwell and wound healing assays. MMP9 and PI3K/Akt signal transduction protein expression after artesunate treatment was measured by WB. Results (1) IHC staining showed that synovial MMP9 expressed in lining and sublining area with intense nuclear and endochylema staining in RA synovium and the percentage of MMP9+ cells was significantly higher in RA (n=32) than that in OA (n=6) or Orth.A (n=6, Figure 1A, B). (2) Migration and wound healing assays for 12 hours and invasion assay for 24 hours showed that RA-FLS possessed stronger capacity in migration and invasion than OA-FLS or Orth.A-FLS (Figure 1E, F). Artesunate inhabits the migration and invasion capacity of RA-FLS in a dose-dependent manner. MTX also has an inhibition effect on the migration and invasion of RA-FLS, but not HCQ (Figure 2A). (3) MMP9 expression in RA-FLS was significantly higher than that in OA-FLS or Orth.A-FLS (Figure 1C, D). 40μM or 60μM artesunate markedly inhibited the expression of MMP9 in RA-FLS by WB (Figure 2B). (4) WB analysis showed artesunate suppressed generation of phophso-Akt in a dose-dependent manner which indicated that Akt activity (phophso-Akt/Akt) in 40μM and 60μM artesunate treatment groups were significantly lower than that in untreated group (Figure 2C). Conclusions Artesunate could inhibit the migration and invasion capacity of RA-FLS and the expression of MMP9 through suppressing Akt activity. Acknowledgements This work was supported by National Natural Science Foundation of China (81671612 and 81471597), Research Project of Traditional Chinese Medicine Bureau of Guangdong Province (20161058) and Guangdong Natural Science Foundation (2014A030313074). Disclosure of Interest None declared

AB0813 High Prevalence of Urolithiasis Due To Excess Urinary Uric Acid Concentration and Calcium Excretion in South Chinese Gout Patients: Table 1.

Background Urolithiasis greatly impact urate lowering therapy in Chinese gout patients. Benzbromarone is contraindicated and Chinese is high risk of allopurinol hypersensitivity syndrome. Febuxostat is too expensive for many patients. Few study about urolithiasis in Chinese gout patients are presented. Objectives To investigate the prevalence and risk factors of urolithiasis in south Chinese gout patients. Methods Patients with primary gout were recruited in the present cross-section study. Urolithiasis was defined as positive stone history and/or ultrasonography. All inpatients with estimated glomerular filtration rate (eGFR) over 30 ml/min/1.73 m2 underwent 24 hours urinary chemistry assay including uric acid (UA), UA concentration, clearance of UA, Cr, calcium, phosphorus, potassium, sodium and chloride. Logistic regression were performed to examine association of urolithiasis with independent variables including age, gender, duration of gout, sUA, previous urate lowering therapy, serum creatinine, eGFR, body mass index, urine pH and 24 hours urinary chemistry assay. Results (1) Two hundred and nighty-four patients were recruited. Mean age of male (N=255) and female (N=39) were 54.4±16.4 and 67.2±15.3, respectively. Average serum UA was 9.0±2.5mg/dl and 25.9% of patients presented tophi. Allopurinol, benzbromarone, or a combination of these two drugs had been prescribed in 97 patients (33.0%), 18 patients (6.1%) and 36 patients (12.2%), respectively. The rest 143 patients (48.6%) had not received urate lowering therapy before. (2) One hundred and eleven gout patients (37.8%) complicated with urolithiasis and urolithiasis was observed in 69 of them (62.1%) on ultrasonography. Compared with non urolithiasis group, urolithiasis group had significant higher serum creatinine (1.6±0.6 VS 1.3±0.3 mg/dl], lower eGFR (56.3±18.0 VS 64.1±18.4 ml/min/1.73m2) and higher alcohol overuse (38.7% VS 26.2%) (P<0.05). (3) Among 102 patients performed 24 hours urinary chemical assay, 45 patients complicated with urolithiasis. Urolithiasis group had significantly higher 24 hours urine UA concentration than non-urolithiasis group (30.4±13.1 VS 23.9±11.9 mg/dl, P=0.01). There were no significant difference of other variables between two groups. Prevalence of urolithiasis increased significantly across increasing quartiles of urinary UA concentration (P=0.012, Table 1). (4) Logistic regression suggested that risk factors of urolithiasis were urinary UA concentration grouped by quartile (P=0.05) and urinary calcium excretion [OR 1.26 (1.01, 1.57), P=0.04]. Urinary UA concentration over 24.4mg/dl was associated with increasing risk of urolithiasis (Table 1).Table 1. Prevalence of urolithiasis among quartiles of urinary UA concentration Quartiles of urinary UA concentration (mg/dl) I (<17.6) II (17.6–24.3) III (24.4–34.9) IV (≥35.0) Median (mg/dl) 12.8 20.8 30.0 42.5 Prevalence* 13.3% (6) 22.2% (10) 33.3% (15) 31.1% (14) Adjusted OR# 1 2.47 (0.66, 9.24) 5.5 (1.50, 20.72) 4.58 (1.24, 16.92) P# – 0.18 0.01 0.02 *Test for a linear trend P=0.012. #By logistic regression. Conclusions Prevalence of urolithiasis in Chinese gout patients were high and predicted by excess urinary UA concentration and urinary calcium excretion. Acknowledgement The present study was supported by Guangdong Natural Science Foundation, China (Grant no. 2014A030310086) to Qian-Hua Li. Disclosure of Interest None declared

AB1020 High Prevalence of BF% Obesity in Chinese Patients with Rheumatoid Arthritis: A Cross-Sectional Study

Background There is about 14%–19% lipid of weight in normal people and most of the lipid stores in fat cells that can secrete adipokines to promote inflammation, which may exacerbate rheumatoid arthritis (RA) synovial inflammation, rise severity of clinical feature, disable functional capacity and reduce quality of life. A worldwide study in 15 countries (mainly in Europe and the United States) identified 18% of RA patients as obese defined by body mass index (BMI ≥30 kg/m2), while higher prevalence of 25% in a USA-based study and 31% in a UK–based study were reported. However, little is known about the prevalence of obesity in Chinese RA patients. Objectives To investigate the prevalence and character of obesity in Chinese RA patients. Methods Two hundred and forty–seven consecutive RA patients were assessed BMI, waist circumference (WC), waist–to–hip ratio (WHR) and waist–to–height ratio (WHtR). Clinical data including RA disease activity, physical function and complications were collected. Body fat percentage (BF%) was assessed by bioelectric impedance and obesity by BF% was defined as >25% for men and >30% for women. Results (1) According to Chinese criteria of BMI, there were 19% patients with overweight and 5% with obesity. According to BF%, there was 52% patients with obesity and female RA patients had significantly higher prevalence of obesity than male patients (55% vs 31%, P=0.006, Figure 1). (2) Weight, total fat mass and trunk–to–appendicular fat ratio (TAFR) were significantly higher in BF% obesity patients than normal ones (all P<0.05). The percentages of patients whose fat distributed mainly in trunk rather than appendicular extremities (TAFR >1) was also higher in BF% obesity patients than normal ones (83% vs 43%, P<0.001, Table 1). (3) According to WC, WHR and WHtR, there were 33%, 41% and 42% patients with central obesity respectively. The trunk-fat-to-weight percentage (TfW%) was significantly higher in central obesity patients (according to WC in Chinese criteria) than that in normal WC patients (female: 18.7% (16.6%–19.8%) vs 13.6% (11.0%–15.7%); male: 15.0% (12.4%–18.3%) vs 7.4% (3.8%–10.6%), both P<0.001). ROC curve analysis showed that the cut–off value of the TfW% for diagnosing central obesity was 11.8% in men with sensitivity 91.7% and specificity 87.5% and 16.3% in women with sensitivity 81.2% and specificity 83.1% (male: AUC=0.941, 95%CI: 0.868–1.0; female: AUC=0.865, 95%CI: 0.811–0.919, both P<0.001). There were 95 (38%) patients with central obesity according to the cut–off value of the TfW% (female 38% and male 39%, Figure 1). (4) Comparing with normal BF% patients, BF% obesity patients were older with higher disease activity indicators (ESR and CRP) and had more complications such as dyslipidemia and fat liver (all P<0.05, Table 1). Conclusions This cross–sectional study suggests that high prevalence of BF% obesity in Chinese RA patients especially in female patients which might be associated with disease activity. Acknowledgement This work was supported by National Natural Science Foundation of China (81471597), Specialized Research Fund for the Doctoral Program of Higher Education (20130171110075) and Guangdong Natural Science Foundation (2014A030313074). Disclosure of Interest None declared

THU0025 Over-Expressed PGC-1β in CD14+ Monocytes of Rheumatoid Arthritis Patients and Its Down-Regulation Can Suppress Osteoclastogenesis and Bone Resorption through Inhibition of Cathepsin K and Trap

Background Peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC-1) is a transcriptional coactivator that plays important roles in regulating energy metabolism and cytokine signaling pathways. Our previous study showed that down-regulating PGC-1β could inhibit rheumatoid arthritis fibroblast-like synoviocytes induced osteoclastogenesis by RAW264.7 (used as precursor of osteoclasts). Objectives To investigate the expression of PGC-1β in CD14+ monocytes from RA patients and its effect and underlying mechanism on osteoclastogenesis and bone resorption. Methods (1) Peripheral blood mononuclear cells (PBMCs) were collected from 3 patients with active RA and 3 healthy controls and CD14+ monocytes were selected by flow cytometry. PGC-1β expression was detected by immunofluorescence staining or flow cytometry. (2) PGC-1β in RAW264.7 was depleted by lentivirus short hairpin RNAs and then cultured with recombinant murine RANKL (50ng/ml) and M-CSF (25ng/ml). Tartrate-resistant acid phosphatase (TRAP) staining and western blot (WB) for detecting the expression of DC-STAMP, cathepsin K and TRAP were performed at day 7. Toluidine blue staining for examining resorption pits by reflected light microscopy and image analysis system was performed at day 14. (3) After PGC-1β knockdown in RAW264.7, cytoplasmic protein was extracted for WB determining the expression of JNK, p-JNK, p38, p-p38, p-ERK1/2, NFATc-1, NF-κB and IκB, while nuclear protein was extracted for WB determining the expression of PGC-1β, p- NF-κB, ERK1/2, c-jun and c-fos. Results (1) Immunofluorescence staining showed that the percentage of PGC-1β positive PBMCs in RA was significantly higher than that in healthy controls (94±3% vs. 57±7%, P=0.021, Figure 1A). Flow cytometric analyses showed that PGC-1β expression in CD14+ monocytes from RA patients was higher than that of healthy controls (Figure 1B) and the mean fluorescence intensity was significantly higher than that of healthy controls (274±23 vs. 167±15, P=0.034).(2) At day 7, the number of TRAP-positive multinucleated osteoclasts in sh-PGC-1β group was significantly lower than that in sh-GFP group (33.4 ± 3.4 vs. 192.5 ± 5.1 cells/per well, P=0.021, Figure 1C). At day 14, the pit area of bone resorption lacunae on the slices of sh-PGC-1β group was significantly reduced than that of sh-GFP group (13 ± 2 vs. 197 ± 15 μm2/per slice, P=0.012, Figure 1C). (3) WB assay showed that the protein expression of cathepsin K and TRAP,but not DC-STAMP, were obviously suppressed in sh-PGC-1β group (Figure 1D). Further analysis of signaling pathways showed the expression of NFATc1 and phosphorylate NF-κB p65 were also significantly decreased (Figure 1E). Conclusions Our results showed that over-expressed PGC-1β in CD14+ monocytes of RA patients and down-regulation of PGC-1β can suppress RANKL induced osteoclastogenesis and bone resorption through inhibition of cathepsin K and TRAP by NF-κB and NFATc1 pathway. Acknowledgement This work was supported by National Natural Science Foundation of China (81471597), Specialized Research Fund for the Doctoral Program of Higher Education (20130171110075) and Guangdong Natural Science Foundation (2014A030313074). Disclosure of Interest None declared

AB0216 Overexpression of Synovial Lining Peroxisome Proliferator-Activated Receptor-Gamma Coactivator-1β Involved in Joint Destruction through Upregulating MMP-3 in Rheumatoid Arthritis

Background Our previous study showed that suppression of peroxisome proliferator-activated receptor-gamma coactivator-1β (PGC-1β) alleviated the secretion of matrix metalloproteinase (MMP)-3 from fibroblast-like synoviocytes and inhibited osteoclastogenesis in vitro. However, little was known about PGC-1β with joint destruction in RA patients. Objectives To investigate the expression and correlation of synovial PGC-1β with joint destruction in RA patients. Methods Eighty-one patients with active RA were recruited and followed up for one year. Serum MMP3 was detected by ELISA. Synovial tissue was obtained by closed-needle biopsy for H&E and immunohistochemistry staining for PGC-1β, MMP-3, CD3, CD20, CD38, CD68 and CD15. X-ray assessment of hand/wrist was repeated at baseline and one year and radiographic progression was defined as TSS≥0.5 unit. Results (1) PGC-1β expression in RA was observed with intense nuclear staining in lining cells and sublining inflammatory cells (including macrophages, lymphocytes and plasma cells) which were significantly higher than osteoarthritis (OA) or orthopedic arthropathies (Orth.A, Fig. 1A). (2) The percentage of lining PGC-1β+ cells significantly correlated with serum and synovial MMP-3 (r=0.394 and 0.376, both P<0.01), as well as CRP, ESR, CD15+ neutrophils and CD68+ macrophages in sublining area of RA synovium (r=0.266–0.356, all P<0.05), and the percentage of sublining PGC-1β+ cells significantly correlated with CRP, ESR, total synovitis score, CD3+ T cells, CD20+ B cells and CD38+ plasma cells, CD68+ macrophages in sublining area of RA synovium (r=0.225-0.428, all P<0.05). (3) Forty-three (53%) RA patients had erosive disease (2013 EULAR definition) at baseline and their percentage of lining and sublining PGC-1β+ cells was significantly higher than non-erosive patients (both P<0.05, Fig. 1B). Both percentages of lining and sublining PGC-1β+ cells were significantly correlated with mTSS, joint space narrowing and erosion subscore (r=0.228-0.261, all P<0.05). (4) Thirty-nine patients had finished one year follow-up and 23% of them had radiographic progression. The percentage of lining PGC-1β+ cells was significantly higher in progressive patients than non-progressive patients [83% (79%–91%) vs 75% (65%–82%), P=0.002]. ROC curve analysis showed that the tradeoff value of lining PGC-1β+ cells for predicting 1-year radiographic progression was 78% with sensitivity 89% and specificity 70% (AUC=0.833, 95% CI: 0.689–0.978, P=0.003). (5) Serum and synovial MMP-3 were significantly higher in patients with high synovial lining PGC-1β than that in patients with low synovial lining PGC-1β (both P<0.05, Fig. 1C–E). Multivariate logistic regression analysis showed that high lining PGC-1β+ cells was a significant predictor of 1-year radiographic progression after adjustment for synovial and serum MMP-3 (OR: 15.002, 95% CI: 1.43–156.698, P=0.024, Fig. 1C). Conclusions Overexpression of synovial lining PGC-1β might play important roles in aggravating joint destruction through upregulating MMP-3 in RA. Acknowledgement This work was supported by National Natural Science Foundation of China (81471597), Specialized Research Fund for the Doctoral Program of Higher Education (20130171110075) and Guangdong Natural Science Foundation (2014A030313074). Disclosure of Interest None declared

SAT0048 Overexpression of CCL18 Promotes Migration and Activation of Fibroblast-like Synoviocytes in Rheumatoid Arthritis

Background CC chemokine ligand 18 (CCL18) has been reported overexpressed in numerous inflammatory disorders since 1997. However, its functional receptor, phosphatidylinositol transfer membrane-associated phosphatidylinositol transfer protein 3 (PITPNM3), has not been discovered until 2011 by our colleagues. Multiple functions of CCL18 besides its chemotactic activity were then identified, including promoting cytokine production, migration/invasion of cancer cells, type I collagen production by human fibroblasts of lung or skin. The effect on the pathogenesis of rheumatoid arthritis (RA) remains unclear. Objectives To explore the expression of CCL18 in RA patients and its effect on RA fibroblast-like synoviocytes (FLS). Methods CCL18 in serum and synovial fluid was measured by ELISA. Synovial tissue was obtained by closed-needle biopsy for H&E and immunohistochemistry staining, and FLS culture in vitro. Expression of PITPNM3 on cell membrane was detected by western blot. Cell proliferation was identified by cell counting kit (CCK-8) and migration ability was analyzed by transwell assay. Cytokines (IL-1β, IL-6, IL-17A, TNF-α, GM-CSF), chemokines (CCL2, CCL3, CCL5, CCL8) and MMP3 in culture supernatant were measured by Cytometric Bead Array (CBA) or ELISA. Results (1) Serum CCL18 of 51 active RA patients was 112 ng/mL (IQR, 85–132), which was significantly higher than healthy controls (n=11, 64 ng/mL (IQR, 36–70), p<0.001, Figure 1A). Eighteen RA patients had synovial fluid and CCL18 in synovial fluid was 1229 ng/mL (IQR, 934–1540) which was significantly higher than corresponding serum level (p<0.001) and synovial fluid CCL18 of osteoarthritis patients (n=7, 33 ng/mL (IQR, 25–229), p=0.001). (2) Immunohistochemistry staining showed CCL18-positive cells in lining and sublining area of RA synovium (n=48), which were significantly greater than osteoarthritis synovium (both p=0.001, Figure 1B∼D). Double-immunocytofluorescent staining showed vimentin-positive RA-FLS in vitro expressed PITPNM3 (Figure 2A) and western blot of membrane protein showed the expression of PITPNM3 protein on RA-FLS. (3) RA-FLS was incubated with different concentrations of CCL18 (0, 100, 250, 500 ng/mL) and CCK-8 proliferation assay showed no significant impact throughout 9 days (Figure 2B). Transwell assay showed that the migration ability of RA-FLS was significantly enhanced after stimulation of CCL18 (500 ng/mL) for 48 hours (Figure 2C). IL-6, CCL2 and MMP3 in culture supernatant were significantly increased after stimulation of CCL18 (500 ng/mL) for 48 hours (Figure 2D∼F). Conclusions Our preliminary results show overexpression of CCL18 in synovial tissue and fluid of RA patients can stimulate migration and activation of RA-FLS probably through the interaction between CCL18 and PITPNM3. Acknowledgement This work was supported by National Natural Science Foundation of China (81471597), Specialized Research Fund for the Doctoral Program of Higher Education (20130171110075) and Guangdong Natural Science Foundation (2014A030313074). Disclosure of Interest None declared