Journal of Applied Physiology, Vol 64, Issue 4 1354-1358, Copyright © 1988 by American Physiological Society
Low plasma concentrations of ionized calcium in patients with asthma
M. Gugger, M. Staubli, E. Peheim and H. Bachofen
Department of Medicine, University of Bern, Inselspital, Switzerland.
It has been suggested that calcium homeostasis is abnormal in the vascular
smooth muscle of hypertensive patients and in the bronchial smooth muscle
in asthmatics. We have found the mean baseline concentration of plasma
ionized calcium to be significantly lower both in 12 asthmatics with
exercise-induced asthma (EIA) [1.16 +/- 0.01 (SE) mmol/l, P less than
0.001] and in 20 asthmatics without EIA (1.16 +/- 0.01; P less than 0.001)
compared with 42 healthy subjects (1.24 +/- 0.01). The mean concentrations
of plasma ionized calcium were not significantly different in asthmatics
with and without EIA when measured either before treadmill exercise, during
the last seconds of this exercise, or 10 or 20 min after exercise but were
significantly lower than in another seven healthy subjects who undertook
the same exercise protocol. Total plasma calcium concentrations in the
three exercising groups were not significantly different at any point in
time. The results suggest that in bronchial asthma an alteration of calcium
metabolism may be important, but they also suggest that there is no simple
relationship between the plasma ionized calcium concentration and acute
exercise-induced bronchoconstriction.
