Microbiota and oxidant-antioxidant balance in systemic lupus erythematosus

Background: Systemic lupus erythematosus (SLE) is a chronic inflammatory disease of autoimmune nature, in which oxidative stress is implicated. Aim: Compare the concentrations of dietary and blood antioxidants, as well as gut microbiota, with serum malondialdehyde (MDA) and C reactive protein (CRP) in 21 subjects suffering from non-active systemic lupus erythematosus (SLE) and 21 age and gender-matched controls. Methods: General biochemical parameters and CRP were determined by enzymatic methods: copper, zinc and selenium by inductively coupled plasma mass spectrometry (ICP-MS), MDA and total antioxidant capacity (TAC) by spectrophotometric methods, gut microbiota by metagenomic analyses and dietary intake by means of food frequency questionnaire. Results: No significant differences were found in diet between lupus patients and the control group, with the exception of trans fatty acids intake, which was higher in patients. In addition, higher concentration of serum copper and lower of zinc in SLE were found. Serum copper was positively associated with CRP and also, this protein with the proportion of Lentisphaerae, Proteobacteria and Verrucomicrobia in feces. Moreover, MDA levels displayed inverse correlations with the Cyanobacteria and Firmicutes groups, while Actinobacteria showed a positive association. The lupus subjects with presence of anti-SSA/Ro were related to higher levels of serum zinc. Conclusion: These results could be useful in the future to go deeper into the understanding of this complex disease.