Effect of anti-TNFalpha treatment on circulating endothelial progenitor cells (EPCs) in rheumatoid arthritis

Rheumatoid arthritis (RA) is associated with increased cardiovascular morbidity and mortality, which may be attenuated by anti-inflammatory treatment. Endothelial progenitor cells (EPCs) have the ability to differentiate into mature endothelium and have a potentially reparative role protecting against ischemia and atherosclerosis.

To investigate the effect of treatment with infliximab on the number and functional capacity of endothelial progenitor cells (EPCs) in patients with RA, as a possible mechanism for reducing cardiovascular morbidity in this disorder.

Active seropositive RA patients (N = 14) considered candidates for starting infliximab treatment, were recruited. Assessment, based on DAS-28, was performed before treatment and 14 days later. Peripheral blood mononuclear cells were isolated and EPC numbers evaluated by the colony-forming unit (CFU) method. Endothelial phenotyping of CFU was performed by immunofluorescence employing antibodies to Tie-2 VEGF-receptor 2, and CD31. EPC Functional properties were evaluated by fibronectin adherance.

A significant 33.4% increase (p < 0.001) in EPC levels was observed after infliximab. A 60% increase was noted in the EPC differentiation scale, (p < 0.002) while a 37.6% increase was observed in mean EPC adhesion (p < 0.001). These changes were associated with a 17.5% decrease in the DAS-28 (p < 0.0001). A significant correlation was observed between the clinical response, reflected by changes in DAS-28 and the degree of increase in EPC CFUs.

A single dose of infliximab improved the number and functional properties of EPCs, in parallel with an early clinical effect, suggesting a possible mechanism by which anti-inflammatory treatment may reduce cardiovascular risk in RA patients.