Evaluation of arterial endothelin-1 levels, before and during a sleep study, in patients with bronchial asthma and chronic obstructive pulmonary disease.

摘要

BACKGROUND: Endothelin (ET)-1 has been implicated in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). The ET-1 levels are elevated during exacerbations of asthma and COPD in bronchoalveolar lavage, serum, and sputum, falling with treatment of the exacerbations. OBJECTIVE: The aim of this study was to examine the ET-1 blood levels in stable asthmatic patients and stable COPD patients during alertness and sleep. MATERIALS AND METHODS: We examined 48 COPD and 20 asthmatic patients. All underwent forced spirometry, measurement of SaO2 and of arterial ET-1 levels and nocturnal polysomnography. ET-1 levels were also determined during nocturnal oxyhaemoglobin desaturation. RESULTS: The daytime SaO2 level of our asthmatic patients was higher than that of our COPD patients (p < 0.001). Daytime SaO2 level of our non-desaturator COPD patients was higher than that measured in desaturator COPD patients. Nightime SaO2 level in our asthmatic patients was higher than that in our desaturatorCOPD patients (p < 0.001). Daytime ET-1 levels in desaturator COPD patients were higher than those observed in normal individuals, in non-desaturator COPD patients and in asthmatic patients. The COPD desaturator patients had higher levels of ET-1 during nighttime than during daytime (p < 0.001). CONCLUSION: Asthmatic patients did not exhibit desaturation of haemoglobin during the night. ET-1 levels are significantly higher in desaturator COPD patients compared with non-desaturator COPD patients, both during the day and during the night. ET-1 levels in stable COPD patients are significantly higher than in patients with stable asthma. These findings are consistent with the hypothesis that ET-1 is implicated in the pathogenesis of COPD and asthma.