Antioxidant status after iloprost treatment in patients with Raynaud's phenomenon secondary to systemic sclerosis

Oxidative stress is involved in pathogenesis of Raynaud's phenomenon (RP), a hallmark of systemic sclerosis (SSc). Frequent episodes of ischemia-reperfusion may lead to release of free radicals and enhanced lipid peroxidation reflected by elevated levels of malondialdehyde (MDA). The failure of native antioxidants (Catalase [CAT], Superoxide dismutase [SOD], and Ceruloplasmin [CP]) might be crucial in endothelial cells damage in RP. Iloprost (IL) synthetic prostacyclin analogue is currently used in the treatment of SSc patients with RP. The objectives of this study were to compare the serum levels of MDA and CP, CAT and SOD activity in red blood cells hemolysate in SSc patients compared to healthy controls; and to study the effect of 5-days IL infusions on MDA and CP levels, and CAT and SOD activity in SSc patients with RP. Twelve SSc patients were treated with 50 mu g IL for 5 days. Blood samples were taken before and after day 1st and after day 5th of IL infusions. Levels of CAT were measured according to the Aebi's method; SOD, according to the Misra and Fridovich method; MDA, according to Slater's method; and CP, according to Ravin's method. Activities of CAT (p<0.001) and SOD (p<0.04) were significantly reduced; levels of CP (p<0.006) and MDA (p<0.06) were raised in SSc compared to controls. IL infusions caused reduction in MDA (p<0.0001) levels and enhanced production of SOD (p<0.006) and CAT (p<0.003). The levels of CP did not change (p=0.48). Oxidant status in SSc patients with RP is impaired. Therapy with IL led to normalization of antioxidant activity. We suggest that CAT may be a sensitive and reliable laboratory marker of oxidative stress severity in RP. We found that IL, in addition to its vasoactive properties, has a potential to activate inner antioxidant system. Activation of inner antioxidant activity may explain long-term effect of IL instead of its very short half-life time.