FRI0368 VASCULAR CALCIFICATION BY INFLAMMATION COULD BE AN IMPORTANT CAUSE OF CARDIOVASCULAR DISEASE IN PATIENTS WITH ANKYLOSING SPONDYLITIS

Background Patients with ankylosing spondylitis (AS) have a higher risk of cardiovascular disease. Atherosclerosis is a main pathological process of cardiovascular disease and calcified plaque is a characteristic feature of atherosclerosis. Inflammation plays a potential role in vascular calcification. There is no previous study revealing the mechanism of vascular calcification in AS. Objectives We investigated the relationship between vascular calcification and inflammation in patients with AS. Methods Sixteen male patients aged over 20 years with AS were enrolled. They fulfilled the modified New York criteria and each of their ankylosing spondylitis disease activity score was more than 2.1. Sex and age matched nine healthy controls were also recruited. Mouse MOVAS (American Type Culture Collection, ATCC®, CRL-2797TM) vascular smooth muscle cells were stabilized in maintenance medium for 24 hours. Then the amount of serum equivalent to 10% of maintenance medium from subjects was added and cells were stimulated for another 72 hours. We exchanged this medium with calcification medium every third day and cells were cultured for another 11 days. After 2 weeks, cells were stained with Alizarin Red S and the optical density (OD) was measured while being compensated by cell viability. For Western blotting, cells were stabilized for 24 hours and stimulated for another 72 hours through the same procedure as that of Alizarin Red S staining. Then we measured the level of protein expression in PPAR-gamma, beta-catenin, TNF-a, interleukin (IL)-23, and MMP7. Results The level of OD of MOVAS cells treated with serum from AS patients (19.503 ± 6.422, mean ± SD) was significantly higher than that from controls (12.724 ± 5.746) (P=0.027, Mann-Whitney test). The level of MMP7 expression of MOVAS cells treated with serum from AS patients (1.921 ± 0.702) was significantly higher than that from controls (0.779 ± 0.191) (P=0.000, Mann-Whitney test). The level of beta-catenin expression of MOVAS cells treated with serum from AS patients (1.292 ± 0.356) was significantly higher than that from controls (0.887 ± 0.310) (P=0.025). There was negative correlation between PPAR-gamma and TNF-a (rho=-0.762, p=0.028, Spearman rank correlation coefficient), and between PPAR-gamma and IL-23 (rho=-0.601, p=0.039); positive correlation between MMP7 and TNF-a (rho=0.833, p=0.010), and between MMP7 and IL-23 (rho=0.797, p=0.002). Conclusion Serum from AS patients showed increased calcification of vascular smooth muscle cells than serum from controls. The level of vascular calcification marker from vascular smooth muscle cells treated with serum from AS patients was significantly higher than that from controls. There were negative relationship between inflammatory markers and inhibitory marker of vascular calcification but positive relationship between inflammatory markers and stimulatory marker of vascular calcification. These findings suggest that vascular calcification by inflammation could be an important cause of cardiovascular disease in AS patients. Acknowledgement This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education (NRF-2017R1D1A1B03030825) Disclosure of Interests Seung Yun Lee: None declared, Seong-Ryul Kwon: None declared, Su-Ah Yoon: None declared, Kyong-Hee Jung: None declared, Won Park Consultant for: Celltrion, Inc, Shin-Goo Park: None declared, Mie Jin Lim: None declared