Exhaled nitric oxide and pulmonary response to iloprost in systemic sclerosis with pulmonary hypertension

Abstract

Widespread endothelial damage occurs in patients with systemic sclerosis, a disease frequently complicated by increased pulmonary artery resistance. 1 Ungerer RG Tashkin DP Furst D et al. Prevalence and clinical correlates of pulmonary artery hypertension in progressive systemic sclerosis. Am J Med. 1983; 75: 65-74 Summary Full Text PDF PubMed Scopus (239) Google Scholar The synthesis and release of nitric oxide (NO) are thought to be impaired in these patients. NO is produced by various cells in the lower respiratory tract, including pulmonary vascular endothelial cells, and can be measured in expired air. 2 Gustafsson LE Leone AM Persson MG Wiklund NP Moncada S Endogenous nitric oxide is present in the exhaled air of rabbits, guinea-pigs and humans. Biochem Biophys Res Commun. 1991; 181: 852-857 Crossref PubMed Scopus (807) Google Scholar A decreased NO concentration in the exhaled air of patients with systemic sclerosis and pulmonary hypertension has been reported. 3 Cailes JB Kharitonov S Yates D Barnes P Dubois RM Decreased endogenous nitric oxide in the exhaled air of systemic sclerosis patients with pulmonary hypertension. Thorax. 1995; 50 (abstr): 452P Google Scholar Although aerosol administration of iloprost, a stable analogue of prostaglandin, is increasingly used in the treatment of pulmonary hypertension associated with collagen disease, 4 Olschewski H Walmrath D Schermuly R Ghofrani A Grimminger F Seeger W Aerosolized prostacyclin and iloprost in severe pulmonary hypertension. Ann Intern Med. 1996; 124: 820-824 Crossref PubMed Scopus (408) Google Scholar the responsiveness of the pulmonary vasculature may not be uniform among patients. In this respect, the presence or absence of structural and functional changes in lung vessels may be important. Measurement of exhaled NO after pharmacological stimuli could represent a non-invasive method to functionally evaluate pulmonary endothelium and, possibly, to identify which patients are more responsive to vasodilating drugs.