MICROCIRCULATORY FUNCTIONS IN SYSTEMIC-SCLEROSIS - ADDITIONAL PARAMETERS FOR THERAPEUTIC CONCEPTS

To study the functional reactivity of the cutaneous microcirculation i n progressive systemic sclerosis (PSS), hyperemic responses after arte rial occlusion (3 min) and during local heating (42-degrees-C) were in vestigated with simultaneous measurements of red blood cell flux and c utaneous oxygen tension (p(cu)O2) of the skin in female patients (n = 19) with PSS and in healthy female controls (n = 15). Additionally, se rum levels of 6-keto-prostaglandin 1alpha (PGF1alpha), a stable metabo lite of prostacyclin, were compared to the microcirculatory data, and both were used to evaluate further a standardized therapy with 10-d in travenous calcitonin (100 IU/d) infusion in six PSS patients. In PSS, the initial mean p(cu)O2 value was significantly reduced and was inver sely proportional to flux and to PGF1alpha levels, whereas the flux an d p(cu)O2 responses to the above hyperemic stimuli showed significant reductions, revealing a pattern of ''hyperemic hypoxia'' probably due to exhausted functional reserves of cutaneous perfusion. During calcit onin infusion significant rises in p(cu)O2 and temporarily in PGF1alph a and flux were found. After 10 d of therapy, increased p(cu)O2 was as sociated significantly with decreased flux, indicating a shifting of b lood from deeper regulatory vessels to the subepidermal capillaries. B oth clinical improvement and the results of microcirculatory measureme nts demonstrate a beneficial effect of calcitonin on the cutaneous mic rocirculation in PSS patients, possibly due in part to a short-term in crease in release of endogenous prostacyclin from the vascular endothe lium during the infusion. The disturbed reactivity of the dermal vesse ls in PSS is important for the evaluation of therapeutic concepts and stresses, together with the elevated PGF1alpha plasma levels, vascular factors in the pathogenesis of PSS.