Peroxisome proliferator-activated receptor gamma expression in peripheral monocytes from rheumatoid arthritis patients

Aim of the workTo study peroxisome proliferator activated receptor gamma (PPARγ) expression levels in the peripheral monocytes from rheumatoid arthritis (RA) patients and to clarify its relation with disease activity, functional disability and drug therapy.Patients and methodsThirty RA patients (Group 1) were divided into two subgroups: Group 1A: patients with moderate to high disease activity (n = 15); Group 1B: patients in remission or with low disease activity (n = 15). Thirty healthy volunteers were included as control group. Disease activity score in 28 joints (DAS-28) and Health Assessment Questionnaire (HAQ) were assessed in patients. PPARγ gene expression levels were assessed by real-time PCR in peripheral blood monocytes.ResultsThe mean fold increase in monocyte PPARγ expression levels was significantly higher (p < 0.001) in patients (6.87 ± 0.9) compared to control, being significantly higher (p < 0.001) in patients with remission or low activity (Group 1B) (7.6 ± 0.63) than patients with active RA (Group 1A) (6.13 ± 0.52). In RA patients, monocyte PPARγ expression levels showed significant negative correlations with morning stiffness durations, total joint count, visual analog scale for pain, DAS-28 and HAQ (p > 0.001) and with swelling joint count, erythrocyte sedimentation rate and platelet count (p < 0.05). A significant correlation was present with disease duration (p < 0.05) while there were no statistically significant correlations with any of Larsen score, C-reactive protein, hemoglobin concentrations, white blood cell count, rheumatoid factor or anti-cyclic citrullinated peptide titers (p > 0.05).ConclusionsOur findings support the role of PPARγ in the pathophysiology of RA and suggest that over-expression of PPARγ protein may have anti-rheumatic effects.