title: Hydrogen sulphide vasodilates human pulmonary arteries: a possible role in pulmonary hypertension?
abstract: BACKGROUND
  Acute rises in pulmonary artery pressures are associated with a significant mortality and morbidity due to the significant strain on the right ventricle. Although hydrogen sulphide (H2S) has been studied for its potential role in the systemic circulation, little is known of its effects on the pulmonary circulation in humans. We studied the effect of H2S at both the human isolated pulmonary arterial level as well as the human isolated perfused lung level.
  
  
  METHODS
  Human lobar pulmonary artery rings (n=12) and lobes (n=3) were obtained from resections for patients with bronchial carcinoma. Pre-constricted fresh rings were mounted in organ baths containing normoxic Krebs solution and subsequently exposed to hydrogen sulphide whilst tension was recorded. Isolated perfused human lung models consisted of lobes ventilated via a bronchial cannula and perfused with Krebs via a pulmonary artery cannula; hydrogen sulphide was added to the perfusate and the resulting pulmonary artery and bronchial pressures were recorded.
  
  
  RESULTS
  We found that 500μM H2S caused a mean dilation of 42.3% (±5.4) from the pre-constricted tension (p<0.005) in isolated arterial rings. In addition, 500μM H2S caused a 17.73% (3.52) reduction in pulmonary artery pressures (p<0.05). Furthermore, we found that 500μM H2S caused a 14.9% (6.01) reduction in bronchial airway pressures (p<0.05).
  
  
  CONCLUSIONS
  We have shown that H2S is a potent vasodilator of human pulmonary arteries and is a significant anti-hypertensive for pulmonary artery pressures. Our results indicate that this therapeutic potential should be further evaluated in clinical trials.
authors.affiliation: Department of Cardiothoracic Surgery, Castle Hill Hospital, Cottingham, UK. Electronic address: priyadariyaratnam@yahoo.co.uk.
authors.forename: Priyadharshanan
authors.initials: P
authors.lastname: Ariyaratnam
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Loubani
authors.forename: Alyn H
authors.initials: AH
authors.lastname: Morice
mesh_terms: D062186:Arterial Pressure / Q000187:drug effects*; D001980:Bronchi / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D006976:Hypertension, Pulmonary / Q000188:drug therapy* / Q000503:physiopathology; D066298:In Vitro Techniques; D010477:Perfusion; D011312:Pressure; D011651:Pulmonary Artery / Q000187:drug effects* / Q000503:physiopathology; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D014665:Vasodilator Agents; D006862:Hydrogen Sulfide