Irisin is associated with atherosclerosis in females with lupus nephritis

Background: Lupus nephritis (LN) is a common presentation for systemic lupus erythematosus (SLE) in rheumatology practice. SLE is associated with increased risk of atherosclerosis. Irisin plays a potential role in preventing atherosclerosis. Aim of the work: This study aimed to measure serum irisin level and carotid intima media thickness (CIMT) and to unravel the possible risk factors for atherosclerosis in females with LN. Patients and methods: This study was carried out on 55 females with LN and 55 matched controls. Laboratory investigations included urinary protein/creatinine ratio, anti-double stranded deoxyribonucleic acid (anti-dsDNA) titre and lipid profile and carotid intima media thickness (CIMT) estimated by duplex ultrasound. The SLE disease activity index (SLEDAI) was assessed. Serum irisin level was measured by enzyme linked immunosorbent assay. Results: CIMT was 0.8 +/- 0.12 mm in cases, and serum irisin mean was 10.3 +/- 3.1 ng/ml. Serum irisin significantly correlated with high density lipoprotein (HDL) (r = 0.3,p < 0.0001) and inversely with platelet count (r = -0.29, p = 0.03), anti-ds-DNA titre (r = -0.25,p = 0.05), LDL (r = -0.46,p < 0.0001) and SLEDAI (r = -0.37,p = 0.005). The CIMT significantly correlated with white blood cell count (r = 0.23,p = 0.05), platelets count (r = 0.28,p = 0.03), protein/creatinine ratio (r = 0.33,p = 0.01), anti-ds-DNA titre (r = 0.35,p = 0.007), LDL (r = 0.51,p < 0.0001) and SLEDAI (r = 0.51,p < 0.0001) and inversely with HDL (r = -0.52, p < 0.0001) and serum irisin (r = -0.47, p < 0.0001). Univariate logistic regression showed that only serum irisin level was an independent risk factor for atherosclerosis (OR = 4.5, CI = 1.5-11.1, P value 0.004). Conclusion: Serum irisin is considered an independent risk factor for atherosclerosis in females with LN.