Inhibition of endothelial progenitor cells may explain the high cardiovascular event rate in patients with rheumatoid arthritis

BACKGROUND: Rheumatoid arthritis (RA) patients may suffer cardiovascular (CV) events much more than the general population, and CV disease is the leading cause of death in patients with RA. Our hypothesis was that impaired function of endothelial progenitor cells may contribute to endothelial dysfunction and the clinical CV events of patients with RA. METHODS: About 27 RA patients (9 males and 18 females) with an active disease and 13 healthy subjects who served as the control group (nine males and four females) were enrolled to this prospective study. The ability to grow in culture colony-forming units of endothelial progenitor cells (CFU-EPCs) was measured, as well as their endothelial function using high-resolution ultrasonography of the brachial artery, and levels of C reactive protein (CRP) in the serum. For statistical analysis, we used the Student's t-test. RESULTS: As a group, patients with RA were older (P < 0.0001), had severe endothelial dysfunction (P<0.0001), with impaired ability to grow CFU-EPCs (P<0.0001), and a higher inflammatory state (P = 0001). No difference was observed in BMI. All RA patients had an active disease (DAS28 3.9 ± 0.9) for 9.2 ± 6.5 years. The same differences were observed in both genders. CONCLUSIONS: Patients with RA had an impaired ability to grow EPCs and severe endothelial dysfunction. Inability to grow colonies of EPCs reflects the impaired regenerative capacity of patients with RA and may explain the endothelial dysfunction and the high CV event rate among patients with RA.