Mitochondrial depolarisation and oxidative stress in rheumatoid arthritis patients

Objectives: To investigate mitochondrial membrane integrity, lipid peroxidation and cytotoxicity in peripheral lymphocytes (PL) from rheumatoid arthritis (RA) patients. Design and methods: South African black RA patients (HIV-) were recruited into the study. Mitochondrial membrane potential (Delta psi(m)) was analysed in PL using the JC-1 dye distribution assay and flow cytometry. Correlations between Delta psi(m) and clinical parameters were tested for statistical significance. Cytotoxicity (LDH) and lipid peroxidation (thiobarbituric acid reactive substances (TBARS)) was also determined. Results: Our 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 Delta psi(m) also negatively correlated to absolute lymphocyte counts (r=-0.4041; p=0.0197). Conclusion: These findings suggest a possible role for mitochondrial membrane alterations in the pathology of RA. (C) 2008 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.