endothelin-1 and sarafloxacin

Pulmonary vascular remodeling and dysfunction associated to tobacco smoking might pave the way for the subsequent development of pulmonary hypertension. Its prognosis is dreadful and its underlying mechanisms are so far largely unknown in humans. To assess the potential role of endothelin-1 and its receptors in smokers' pulmonary artery vasoactive properties. Endothelium-dependent vasodilation to ACh was assessed in pulmonary vascular rings from 34 smokers and compared with that of 10 nonsmokers. The effects of ET-A (BQ 123) or ET-B (BQ 788) blockers and that of an ET-B activator (sarafotoxin) were evaluated. Endothelin-1 was quantitated by ELISA. Expression of its receptors was quantitated by Western blotting. Smokers exhibited an impaired pulmonary endothelium-dependent vasodilation compared with nonsmokers (P < 0.01). In the former group, 8 of 34 subjects exhibited a marked endothelial dysfunction (ED(+)) whereas 26 (ED(-)) (P < 10(-4)) displayed a vasorelaxation to ACh that was comparable to that of nonsmokers. In ED(+) subjects, ET-A was overexpressed (P < 0.05) and inversely correlated (P < 10(-2)) with the response to ACh. Sarafotoxin significantly improved vasodilation in all subjects (P < 10(-2)). In conclusion, tobacco smoking is associated to an impaired pulmonary vasorelaxation at least partly mediated by an ET-1/ET-A-dependent dysfunction.

Topics: Acetylcholine; Adult; Aged; Antihypertensive Agents; Blotting, Western; Ciprofloxacin; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin-1; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Middle Aged; Oligopeptides; Peptides, Cyclic; Piperidines; Pulmonary Circulation; Receptor, Endothelin A; Receptor, Endothelin B; Smoking; Vascular Diseases; Vasodilation; Vasodilator Agents

To analyze the effect of endothelin-1 on pulmonary arterial and venous contractile force in vitro and on up- and downstream pulmonary vascular resistance in vivo under sham and endotoxemic conditions in pigs.. In vitro: paired preparations of pulmonary arteries and veins were mounted in a myograph (n=13) for measurements of contractile responses to increasing concentrations of phenylephrine, endothelin-1, and sarafotoxin (endothelin receptor type B agonist). In vivo: 20 pigs were anesthetized, mechanically ventilated, and subjected to phenylephrine (reference substance), endothelin-1, sarafotoxin, endotoxin, and tezosentan (dual endothelin receptor antagonist). Hemodynamic and gas-exchange variables were monitored. Pulmonary capillary pressure, used for calculation of upstream and downstream vascular resistance, was assessed by the pulmonary vascular occlusion technique.. Pulmonary veins were more sensitive than arteries to endothelin-1 both in vitro and in vivo. This difference was more pronounced with sarafotoxin, where almost no arterial effects were noted. In vivo and in vitro exposure to phenylephrine resulted in selective arterial constriction. Endotoxin infusion resulted in pulmonary hypertension with a clear downstream dominance. The latter changes including the increase in capillary pressure were totally abolished by intervention with the dual endothelin receptor antagonist tezosentan.. The endothelin system is extensively involved in endotoxemic pulmonary venous hypertension, an effect possibly mediated by the endothelin B receptor.

Topics: Animals; Ciprofloxacin; Endothelin-1; Female; Hypertension, Pulmonary; Lipopolysaccharides; Lung; Male; Pyridines; Respiratory Distress Syndrome; Sepsis; Swine; Tetrazoles; Vascular Resistance; Vasoconstriction; Vasodilator Agents