WHOLE-BODY COOLING INCREASES PLASMA ENDOTHELIN-1 LEVELS IN WOMEN WITHPRIMARY RAYNAUDS-PHENOMENON

To understand better the role of endothelin-1 (ET-1) in the pathogenes is of primary Raynaud's phenomenon (PRP), we investigated the basal ET -1 plasma levels and changes after whole-body cooling in healthy women and those with PRP. The study was performed as an open parallel-group comparison during the month of February. The Raynaud group included 2 1 female patients (mean age 45.3 years, range 21-57 years) who had had disabling Raynaud's phenomenon for a mean period of 17 years (range 2 -26 years). The control group consisted of 25 healthy women (mean age 43.6 years, range 27-56 years). Plasma levels of ET-1 were measured on two separate occasions: once after 30 min of rest at room temperature and after 40 min of whole-body cooling. There were no significant dif ferences in baseline plasma ET-1 levels between the two groups of wome n. The plasma ET-1 levels increased significantly in the PRP group aft er cold exposure (mean difference 0.11 pmol l(-1), 95% CI 0.005-0.214, P = 0.012). In contrast, the levels of plasma ET-1 in the control gro up did not change significantly after cold provocation. In conclusion, no differences in plasma basal levels of ET-1 were observed between t he two groups. However, women suffering from Raynaud's phenomenon resp onded with a slight but significant elevation in plasma levels of ET-1 after whole-body cooling, whereas the healthy control subjects did no t. The results from the present study confirm previous observations th at endothelial dysfunction may be of aetiological importance in PRP.