Nailfold capillaroscopy assessment of microcirculation abnormalities and endothelial dysfunction in children with primary or secondary Raynaud syndrome

Raynaud syndrome (RS) manifests as episodes of transient spasms of peripheral blood vessels, most often in response to cold. The reason of that symptom (primary RS (pRS)) usually cannot be found but may be accompanied by some autoimmune diseases (secondary RS (sRS)). In this study, we assessed microcapillary status and serum concentrations of chosen cytokines, adhesive molecules, and nitric oxide (NO) in patients with pRS and sRS in comparison with healthy children. Eighty-six patients with RS were enrolled into the study, including 52 with pRS and 34 with sRS. The control group consisted of 29 healthy children. A decrease in myorelaxative and anticoagulant abilities was observed, with simultaneous prevalence of vasopressor substances and procoagulative activity. Therefore, several important factors such as endothelin-1 (ET-1), E-selectin (E-sel), interleukin-18 (IL-18), and nitrogen oxide (NO) were also analyzed. Two types of capillaroscopy status were determined: normal and microangiopathic. There was a significant relationship between presence of microangiopathy and higher serum ET-1 (p = 0.018) and E-sel (p = 0.021) levels. Similarly, we have found a correlation between presence of ANA and higher ET-1 (p = 0.005), but not E-sel (p = 0.241). In patients with pRS, we found significant relationship between ANA and higher ET-1 (p = 0.008). No such relations were observed in sRS patients. Our data indicates that external factor-induced vasoconstrictive effects dominated in pRS, whereas in sRS in the course of connective tissue diseases, it was accompanied by coexistent vasodilation due to endothelial dysfunction. The latter phenomenon is at least partially dependent on insufficient NO release.