Kim Nh

AB0123 Real-Time in Vivo Apoptosis Imaging with a Histone-H1 Targeting Probe for the Measurement of therapeutic Response in an Experimental Arthritis Model

Background Apoptosis is a well-organized process that is an important and active regulatory pathway of cell infiltration within inflammatory tissues. Decision on response after treatment with disease modifying anti-rheumatic drugs in rheumatoid arthritis has been performed by measuring acute phase reactants and clinical parameters such as disease activity score (DAS). Real-time monitoring of apoptosis may improve our decision on the response to therapy. Objectives To examine whether in vivo imaging of apoptosis obtained by uptake of Histone H1-targeting probe labeled with near-infrared fluorescence is able to detect early response and monitor quantitative changes after treatment in a chronic inflammatory arthritis model. Methods Histone H1-targeting probe (CQRPPRC, ApoPep-1) was synthesized using HPLC and labeled with FPR675 near infrared fluorescence dye. To induce apoptosis, cells were treated with staurosporine (STS) or methotrexate (MTX). Apoptotic cells were measured using flow cytometer and confocal microscopy. For in vivo imaging, collagen-induced arthritis (CIA) model was treated with drugs and optical imaging was performed using OpTix Explore. Total photon count (TPC) was measured by the summation of photon counts from the region of interests of four paws. Results Treatment of Jurkat T cells and THP-1 cells with STS and MTX induced apoptosis in a dose-dependent manner, which was detected by binding with ApoPep-1-FITC or annexin V-FITC in combination with propodium iodide in a similar sensitivity. Detection of apoptotic cells using ApoPep-1-FITC within sections of joint tissues from active CIA mice was as effective as that using tunnel assay. In active CIA mice, apoptosis imaging was performed using either annexing V or ApoPep-1 labeled with FPR675 (5 mg/kg, each), which showed a marked enhancement of TPC in ApoPep-1 imaging upto 8 hours after intravenous (i.v.) injection (Figure). According to the stage of disease progression, optical intensity of ApoPep-1-FPR675 was significantly increased compared to that of annexin V-FPR675 from the early stage of arthritis, which showed the most conspicuous difference in active arthritis. After treatment with high dose of MTX (50mg/kg, i.v.), the difference of TPC was greatest after 3 days of treatment compared with control-treated mice. The number of apoptotic cells detected using ApoPep-1-FITC within tissue sections from the joints was significantly increased after treatment with high dose of MTX. Conclusions The present data indicate that in vivo apoptosis imaging with ApoPep-1 is a sensitive tool for early decision on therapeutic response after DMARDs treatment in chronic inflammatory arthritis. Further study is warranted to elucidate the application of this radiation-free imaging tool for human disease. Disclosure of Interest None declared

AB0252 Mortality in Patients with Rheumatoid Arthritis: A Prospective Cohort Study over Two Years

Background Rheumatoid arthritis (RA) patients have an increased risk of mortality, which has been partially attributed to higher cardiovascular mortality. Objectives To determine the mortality and their risk factors over 2 years of follow up in a cohort study. Methods A total of 406 RA patients and 209 age and sex-matched normal controls enrolled in the KNUH Atherosclerosis Risk in RA (KARRA) cohort was assessed according to a standardized protocol for two years. Demographic data, traditional CV risk factors, and clinical and laboratory variables relevant to disease activity were obtained. Erythrocyte sedimentation rate-area under the curve (ESR-AUC) overtime was calculated to assess the inflammatory burden. The carotid intima-media thickness (IMT) and plaques were measured using carotid artery ultrasound. Results Among RA patients, a total 10 deaths (1.25% per year) occurred during 2 years follow-up period while there were no deaths among the controls. Disease duration of RA until deaths was 32.3±34.0 years. Causes of death included infection (4 pneumonia and 2 septic shock), sudden cardiac death (1 patient), congestive heart failure (1 patient), and others (2 patients). Risk factors for mortality included age (alive vs. dead patients: 55±12.1 vs. 71±9.5, p<0.001), functional class of RA (1.9±0.5 vs. 2.4±0.5, p<0.001), modified Korean health assessment questionnaire (mKHAQ) (9.6±7.8 vs. 22.1±13.7, p<0.05), DAS28 (3.3±4.5 vs. 4.6±1.3, p<0.006), ESR (23.3±20.1 vs 64.3±38.2, p<0.01), ESR-AUC (2,005±1,874 vs 4,106±1,649, p<0.01), and carotid artery plaque number (0.7±1.3 vs 2.5±2.1, p<0.05). After multivariate analysis, mKHAQ and ESR were found to be significantly associated with mortality (p<0.01 and p<0.05, respectively). mKHAQ and ESR cut-off points were made using a receiver-operating characteristic (ROC)-curve. Among the patients with mKHAQ <19, no death occurred in patients with normal ESR, while 3 deaths in patients with abnormal ESR (Figure). Mortality was highest among patients with HAQ ≥19 and abnormal ESR (6 deaths among 41 patients, 14.6%). Conclusions These results suggest that functional outcome and inflammatory activity of RA have a critical prognostic impact and tight control of inflammation may improve survival in this population. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.4620