Increased prostacyclin metabolites and decreased red cell deformability in patients with systemic sclerosis and Raynauds syndrome.

Patients with systemic sclerosis (SS) often suffer from Raynaud's Syndrome (RS). As prostacyclin (PGI2) is of benefit in the treatment of RS in SS, we have measured endogenous stable metabolites of PGI2 (PGI2m) in 42 patients with Raynaud's Phenomenon (RP) of varying aetiology (15 SS patients, 15 patients with Raynaud's Disease (RD) but no other symptoms, and 12 other RS patients with probable connective tissue disorder). Results were compared with 15 matched controls. Since abnormally rigid red blood cells (RBC) may occur in SS, we also measured RBC deformability (filtration technique). Results show that the SS group have significantly elevated PGI2m levels compared to patients with RD alone and normal controls. In addition, SS patients have more rigid RBC. If all 42 patients with RS were analysed, a significant correlation between PGF and RBC filtration was obtained. The cells of SS patients are resistant to the effects of PGI2 and it would appear that as a compensatory mechanism, production of PGI2 is increased. Treatment with exogenous PGI2 may overcome this resistance and improve microcirculatory flow. The more rigid RBC in SS may also be related to the increased endogenous PGI2. These results may have important clinical implications and allow new therapeutic approaches.