Oxidative stress, inflammation and disease activity biomarkers in lupus nephropathy

Abstract

Aims: Lupus nephropathy (LN) is a severe and frequent complication of systemic lupus erythematosus and it is associated with significant morbidity and mortality. Here, we assessed biomarkers of oxidative stress, inflammation and disease activity in patients with LN. Main methods: Twenty-two patients with active LN (ALN) and 28 patients with inactive LN (ILN, control group) were studied. Oxidative stress biomarkers catalase (CAT), superoxide dismutase (SOD) and malonyldialdehyde (MDA) were assessed, as well as inflammation biomarkers high-sensitivity CRP (hs-CRP), interleukin 6 (IL-6) and monocyte chemoattractant protein 1 (MCP-1). Renal tubular disease biomarkers neutrophil gelatinase-associated lipocalin (NGAL) and β2-microglobulin (β2-MG) were assessed, together with the classical disease activity biomarkers urinary protein/creatinine ratio (P/Cr), anti-double stranded DNA (anti-dsDNA), anti-C1q antibody and complement proteins C3 and C4. Renal biopsies were also performed for histological classification of LN. Key findings: Significant differences were found between ALN and ILN patients for all the assessed biomarkers (p<0.05), except for CAT, SOD and IL-6 (p>0.05). Eighty three % of ALN patients presented a type III or IV LN and 17 % presented a type I, II or V LN. Significance: There is a disbalance in the redox status in ALN patients that would be involved in lipid peroxidation of the glommerular basal membrane that would alter its integrity and could also affect renal tubular function in these patients.