Mitochondrial depolarisation and oxidative stress in rheumatoid arthritis patients

ObjectivesTo investigate mitochondrial membrane integrity, lipid peroxidation and cytotoxicity in peripheral lymphocytes (PL) from rheumatoid arthritis (RA) patients.Design and methodsSouth African black RA patients (HIV^?) were recruited into the study. Mitochondrial membrane potential (Δψ_m) was analysed in PL using the JC-1 dye distribution assay and flow cytometry. Correlations between Δψ_m and clinical parameters were tested for statistical significance. Cytotoxicity (LDH) and lipid peroxidation (thiobarbituric acid reactive substances (TBARS)) was also determined.ResultsOur findings show significantly elevated levels of cytotoxicity (p = 0.0029) and lipid peroxidation (p = 0.0030) in RA. A significantly higher percentage of circulating PL contained depolarised mitochondria (p = 0.0003) which correlated with disease activity and C-reactive protein levels in patients. Collapse of Δψ_m also negatively correlated to absolute lymphocyte counts (r = ? 0.4041; p = 0.0197).ConclusionThese findings suggest a possible role for mitochondrial membrane alterations in the pathology of RA.