FRI0469 Endothelial Progenitor Cells in Takayasu's Arteritis

Background Takayasu's arteritis (TA) is a rare, chronic inflammatory disease of unknown etiology. The inflammation in this disease leads to stenosis, thrombosis, dilatation or aneurysm in aorta and/or its branches. Endothelial progenitor cells (EPCs) are bone marrow derived immature cells which take part in revascularization and vascular homeostasis. The level of circulating EPCs increases in case of vascular injuries and tissue ischemia. Objectives There is no any specific serologic marker or biochemical test for TA. In this study we aimed to investigate the level of EPCs in patients with Takayasu's arteritis. Methods A total of 26 subjects were included in this case-control study, of whom 11 and 15 subjects were TA or healthy, respectively. The diagnosis of TA is based on American College of Rheumatology TA classification criteria. Patients with a diagnosis of chronic disease other than TA, malignancy, pregnancy, infection, recent surgery or trauma were excluded. Erythrocyte sedimentation rate (ESR) and CRP levels of all subjects were measured. EPCs were defined and measured by flow cytometry according to the expression of CD146, CD31 and CD34. The MedCalc 12.7 software (Belgium) was used for all statistical analyses. The Kolmogorov-Smirnov test was used to show the normal distribution of quantitative measurements; the Chi-square was used to test the statistical significance of the differences in demographic data; and the T test or Mann Whitney U test was used for the comparison of the quantitative measurements (age, EPCs, ESR, CRP) between the two groups. The probability of making a Type I error (alpha, significance) was accepted as 0.05 in all tests. Results Groups were matched in terms of age and sex. The mean ages were 33.1±6.6 and 33.2±9.1 in the study and control groups, respectively (p=0.995). There were 9 (81.8%) and 7 (46.7%) women in the study and control groups, respectively (p=0.109). The levels of EPCs of patients with Takayasu's arteritis were higher than those of controls. The mean level of EPCs was 4.18±2.67 in the study group while it was 2.13±1.30 in the control group. The difference was statistically significant (p=0.016). ESR and CRP levels were also higher in the TA group (20.3±15.5 vs. 10.7±4.9, 5.08±3.74 vs. 1.09±0.36, and p=0.033, <0.001, respectively). Conclusions Although circulating endothelial cells are found to be associated with ANCA-associated vasculitis in this study we have shown high levels of EPCs in patients with Takayasu's arteritis. Takayasu's arteritis is a chronic vasculitis associated with inflammation on arterial walls. Endothelial activation in affected blood vessels is a mediator of vascular inflammation. EPCs migrate to the peripheral circulation in response to pathological stimulation of vascular injury or tissue ischemia. Consequently, these cells may be a useful marker for TA. References Hristov M, Weber C. Endothelial progenitor cells: characterization, pathophysiology, and possible clinical relevance. J Cell Mol Med 2004; 8: 498-508. Arend WP, Michel BA, Bloch DA, et al. The American College of Rheumatology 1990 criteria for the classification of Takayasu arteritis. Arthritis Rheum 1990; 33: 1129-34. Haubitz M, Woywodt A. Circulating endothelial cells and vasculitis. Intern Med 2004; 43: 660-7. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.1941