AB0083 STUDY OF THE ROLE OF ANGIOPOIETIN-LIKE PROTEIN TYPE 4 IN METABOLIC DISORDERS CAUSED BY INFLAMMATION IN RHEUMATOID ARTHRITIS
Authors: A. Aleksandrov, V. Aleksandrov, L. Shilova
Journal: Annals of the Rheumatic Diseases (2020)

Background: Objectives: To assess the potential role of angiopoietin-like protein type 4 (ANGPTL4) in metabolic disorders caused by inflammation in rheumatoid arthritis (RA). Methods: The study included 88 patients with significant RA, 64 patients with other rheumatic diseases (RD) (36 patients with osteoarthritis (OA); 28 patients with psoriatic arthritis (PsA); 17 patients with ankylosing spondylitis (AS)) and 32 healthy individuals. Estimation of ANGPTL4 was carried out by enzyme immunoassay using the commercial test system “RayBio Human ANGPTL4 ELISA Kit” (RayBiotech, USA) in blood serum. Levels of ESR, CRP, RF, antibodies to cyclic citrullinated peptide (anti-CCP) and modified vimentin (anti-MCV) in the ELISA test were determined for all patients with RA. Results: The level of ANGPTL4 in the blood serum of patients with RA was significantly higher than in healthy people (p &lt;0.001) and patients with other RD (p = 0.012 compared with OA; p = 0.046 with PsA; p = 0.008 with AS). ANGPTL4 indices in patients with RA correlated with the age of onset of RA (r = -0.658, p &lt;0.001), disease activity according to DAS-28 (r = 0.449, p = 0.001), level of education (r = 0.235, p = 0.029), dose of glucocorticoid hormones (r = 0.321, p = 0.009) and methotrexate (r = -0.496, p = 0.05), the presence of osteopenia (r = 0.44), signs of kidney damage - proteinuria (r = 0.309, p = 0.037) and hypoalbuminemia (r = 0.386, p = 0.022), as well as with CRP levels (r = 0.488, p = 0.003), ESR (r = 0.458, p = 0.002), serum vitamin D (r = -0.417) and urinary calcium when recalculated to creatinine (r = 0.797, p = 0.032). Patients with RA showed a high frequency of insulin resistance (according to the HOMA-IR index) (1.27 [0.84–1.62] in patients with RA; 0.76 [0.44–1.02] in healthy individuals; p &lt;0.001) and the presence of coronary heart disease, as well as a positive correlation between disease activity (according to DAS-28) and insulin resistance (according to the HOMA-IR index) (p = 0.033). Higher values of C-reactive protein (p = 0.04) and serum ANGPTL4 levels (p = 0.042, compared with patients with RA without type 2 diabetes; p = 0.026, compared with healthy individuals) were determined in the group of patients with RA with the presence of type 2 diabetes. ANGPTL4 acts as an inhibitor of lipoprotein lipase. His contribution to the development of dyslipidemia in RA can be demonstrated by the results we obtained when comparing groups of patients with / without signs of metabolic syndrome (MS). A positive correlation between ANGPTL4 and triglyceride levels (r = 0.42, p = 0.018) was found. An increase in the level of ANGPTL4 in blood serum of patients with RA with MS (p = 0.027 compared with RA without MS) can predict the development of cardiac pathology in this group of patients. Conclusion: ANGPTL4 is directly involved in the regulation of glucose homeostasis, lipid metabolism, and insulin sensitivity. Cardiovascular diseases associated with atherosclerosis, insulin resistance and metabolic syndrome are known as the most common extraarticular manifestations of RA; the study of the role of ANGPTL4 in metabolic disorders caused by inflammation can show a new direction in the development of laboratory and therapeutic technologies in RA. Disclosure of Interests: None declared