Clinical significance of leptin in systemic lupus erythematosus

Abstract

Objective: to study the frequency of hyperleptinemia in patients with systemic lupus erythematosus (SLE), its relationship with clinical and laboratory manifestations of the disease, drug therapy, and other metabolic disorders.Patients and methods. The cross-sectional study included 46 women with a definite diagnosis of SLE (median age 40 [31; 48] years) and disease duration 3.0 [0.9; 9.0] years. Glucocorticoids (GC) were received by 38 (83%) patients, hydroxychloroquine – by 35 (76%), immunosuppressants – by 10 (22%), biologic disease-modifying antirheumatic drugs – by 5 (11%). In all patients, fasting levels of glucose, leptin, apoliproprotein B (ApoB) and immunoreactive insulin were determined, and homeostatic model assessment for insulin resistance (HOMA-IR) was calculated. Concentration of leptin ≥11.1 ng/ml, ApoB – >1.6 mg/ml were considered an elevated level. HOMA-IR index ≥2.77 corresponded to the presence of insulin resistance (IR).Results and discussion. Hyperleptinemia was found in 34 (74%) patients with SLE, an increased level of ApoB – in 19 (41%), IR – in 10 (22%). In patients with hyperleptinemia, serositis, positivity for anti-double-stranded DNA (aDNA) and hypocomplementemia were less common, overweight and obesity were more frequent, the SLEDAI-2K index was lower, the aDNA level was lower, and the concentration of the C3 component of complement, insulin, HOMA-IR index, body mass index (BMI) and disease duration were higher (p<0.05 for all cases). BMI <25 kg / m2 had 26 (57%) women, 14 (54%) of whom had hyperleptinemia. In patients with BMI <25 kg / m2, we found a relationship between leptin concentration and disease duration (r=0.4, p=0.04), SLE activity according to SLEDAI-2K (r=-0.6, p=0.003), levels of aDNA (r=-0.6, p<0.001), C3 component of complement (r=0.5, p=0.01), maximum (r=0.7, p<0.001) and supporting (r=0,5, p=0.023) GC doses.In patients with BMI ≥25 kg/m2 (n=20), no such relationship was observed.Conclusion. Hyperleptinemia was found in the majority of women with SLE; elevated levels of ApoB and IR were much less common. Patients with hyperleptinemia are characterized by a longer duration and less activity of the disease, as well as the presence of overweight and obesity and an increase in the HOMA-IR index. In SLE patients with normal body weight, the concentration of leptin increased along with GC dose elevation.