Patients with rheumatoid arthritis (RA) are prone to premature atherosclerosis. We hypothesize that depletion of circulating endothelial progenitor cells (EPC) related to RA can contribute to the development of atherosclerosis.
We studied coronary calcifications by multidetector computed tomography and their relationship with different subtypes of circulating EPC in 70 patients with RA and 35 age- and sex-matched controls (mean age 54.1 +/- 10.2 yrs, 87% were women). The presence of coronary atherosclerosis was defined as an Agatston score > or = 10. Four subpopulations of EPC were determined by flow cytometry on the basis of surface expression of CD34, CD133, and KDR antigen: CD34+, CD34/KDR+, CD133+, and CD133/KDR+ EPC, respectively.
Among those with RA, 15 patients (21%) had coronary atherosclerosis. The mean Agatston score was higher (61.8 +/- 201.7 vs 0.14 +/- 0.69; p = 0.01) and coronary atherosclerosis was more prevalent (21.4% vs 0%; p < 0.01) in patients with RA compared to controls. RA patients with coronary atherosclerosis were older (66.2 +/- 6.9 vs 51.5 +/- 16.2 yrs; p < 0.01), had higher prevalence of hypertension (46.7% vs 14.5%; p = 0.01), and had lower CD133/KDR+ (0.45% +/- 0.28% vs 0.89% +/- 0.81%; p < 0.01) and CD133+ EPC levels (0.74% +/- 0.39% vs 1.22% +/- 0.83%; p < 0.01), but similar CD34/KDR+ and CD34+ EPC levels (all p > 0.05) compared to those without. Multiple logistic regression revealed that older age (OR 1.25, 95% CI 1.10-1.41, p < 0.01) and lower CD133/KDR+ EPC (OR 0.07, 95% CI 0.00-0.97, p < 0.01) were independent predictors for coronary atherosclerosis in patients with RA.
Our results demonstrated that RA patients with coronary atherosclerosis have significantly lower levels of CD133/KDR+ and CD133+ EPC than those without. In addition to older age, lower levels of circulating CD133/KDR+ EPC also predicted occurrence of coronary atherosclerosis in RA patients.