Defective Peripheral Blood Endothelial Cell Progenitors in Patients with Scleroderma and Psoriatic Arthritis

Vasculogenesis is known to be defective in patients with scleroderma (SS) and psoriatic arthritis (PA) with vessel loss in the former and hypertrophic blood vessels in the latter in affected areas. We studied the number and function of peripheral blood endothelial progenitors (PBEP) in patients with SS and PA to elucidate the mechanism of EC dysfunction.

Materials and Methods: Eleven patients with SS, 13 patients with PA and 7 healthy individuals were studied. We measured CD133+/CD146+ cells in peripheral blood (PB) by immunofluorescence. We performed cell cultures of isolated CD34+ cells in endocult medium and examined the endothelial colonies (EPC). We also performed cocultures of CD34+ and autologous bone marrow stromal cells (BMSC) in double chambers. We also performed cocultures of BMSC from patients and normal endothelial cells from cord blood.

Results: The number of CD133+/CD146+ cell in PB was increased the 2 groups of patients compared to controls. The number of EC colonies in endocult did not differ in the 3 groups. The presence of autologous serum within the culture medium reduced the number of colonies in 3 patients with SS. The number and the size of EC colonies from SS patients in vitro were significantly reduced (p<0.01) after co-cultures of autologous BMSC with CD34+ in culture plates with insert while they were increased (p<0.01) from patients with PA. The same was true when cord blood CD34+ cells were cultured in endocult medium in the presence of BMSC of SS and PA patients.

Conclusion: EC progenitors from patients with SS and PA are increased in PB and develop normal EC colonies in vitro. They developed decreased colonies in SS and increased colonies in PA when cultured together with with autologous BMSC. This means that possible cell-cell or humoral interactions between EC and some cellular component within BMSC affect the survival and differentiation of EC.