Am. J. Respir. Crit. Care Med., Vol 149, No. 4, 04 1994, 946-952.
Blood and bronchoalveolar lavage endothelin-1 levels in nocturnal asthma
M Kraft, WR Beam, SE Wenzel, MR Zamora, RF O'Brien and RJ Martin
Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado 80206.
Endothelin-1 (ET-1) is a potent endogenous vasoconstrictor that was
recently shown to exhibit bronchoconstrictive properties in vitro. In
asthmatic patients, the expression of ET-1 peptide was also shown to be
increased in endobronchial biopsies. Thus, we postulated that ET-1 could be
higher in subjects with nocturnal asthma. Bronchoalveolar lavage (BAL)
fluid levels of ET-1 were measured in 10 subjects with nocturnal asthma and
6 normal volunteers at 0400 h (nighttime groups) and in an additional 7
subjects with nocturnal asthma and 6 control subjects at 1600 h (daytime
groups). ET-1 levels were significantly lower in the nighttime asthmatic
group (median 39.3 pg/mg protein, 7.3 to 44.0 IQ) than in the nighttime
control group (median 77.4 pg/mg protein, 46.8 to 121.9 IQ; p = 0.01) or
the daytime asthmatic group (median 56.8 pg/mg protein, 51.6 to 97.4 IQ; p
= 0.04). ET-1 levels did not differ significantly between the daytime
asthmatic and the daytime control groups or between control groups.
Additionally, the overnight reduction in lung function was significantly
correlated with lower BAL ET-1 levels (r = 0.57, p = 0.05). These results
suggest that ET-1 plays a role in the overnight worsening of asthma and
perhaps is more tightly tissue bound, resulting in lower levels of BAL
fluid.
