Effect of cold exposure, exercise and high altitude on plasma endothelin-1 and endothelial cell markers in man.
Cruden NL., Newby DE., Ross JA., Johnston NR., Webb DJ.
The aims were to examine the effect of cold exposure, exercise and high altitude on plasma concentrations of big endothelin-1, endothelin-1, von Willebrand factor and serum e-selectin in twenty five healthy male volunteers. Clinical evaluation and venesection were performed before and after 24 hours of low altitude mountaineering, exposure to temperatures of -18 degrees C and +4 degrees C and whilst ascending from sea level to an altitude of 5000 m in the Karakoram. Plasma big endothelin-1, plasma endothelin-1 and serum soluble e-selectin concentrations were significantly elevated after two hours at -18 degrees C (p < 0.05, p < 0.05 and p < 0.01 respectively). At +4 degrees C, plasma big endothelin-1 and endothelin-1 concentrations rose significantly after 5 hours (p < 0.005 for both) but not after 2.5 hours. Low altitude mountaineering did not alter circulating marker concentrations. At high altitude, big endothelin-1 and endothelin-1 (p < 0.01 for both) rose significantly at 2500 m and initially at 5000 m but returned to sea level values after prolonged exposure to 5000 m. Serum e-selectin rose at all altitudes greater than sea level (p < 0.05). In conclusion, exposure to high altitude, moderate cold or freezing temperatures, but not exercise, selectively activates endothelial cells increasing endothelin-1 production. Cold exposure may contribute to the observed increase in plasma endothelin-1 in mountaineers at high altitude.