title: Surfactant protein A (SP-A) and angiotensin converting enzyme (ACE) as early biomarkers for pulmonary edema formation in ventilated human lung lobes.
abstract: OBJECTIVE
  Ex vivo perfused and ventilated lung lobes frequently develop pulmonary edema. We were looking for a suitable and early detectable biomarker in the perfusion fluid indicating lung cell damage and loss of tissue integrity in ventilated human lung lobes. Therefore, we elucidated whether surfactant protein A (SP-A) and angiotensin-converting enzyme (ACE) were measurable in the perfusion fluid and whether they were suitable indicators for edema formation occurring within the experimental time frame of 1-2 h.
  
  
  METHODS
  Patients (n = 39) undergoing a lobectomy, bilobectomy or pneumonectomy due to primary bronchial cell carcinoma were included in the studies. Lung lobes were extracorporally ventilated and perfused for up to 2 h. Two different perfusion fluids were used, plain perfusion buffer and perfusion buffer containing packed erythrocytes or buffy coats. Perfusion fluid samples were analyzed for SP-A and ACE using immunoassays served as perfusion fluids.
  
  
  RESULTS
  SP-A and ACE concentrations were analyzed in fluid sample sets of 39 and 33 perfusion experiments, respectively. Degrees of edema formation were arbitrarily classified into three groups (≤ 29, 30-59, ≥ 60 % weight gain). The maximum increase of SP-A and ACE concentrations in the perfusate was significantly higher for more pronounced edemas in case of perfusions using a mixture of blood components and buffer. Interestingly, the time courses of ACE and SP-A were highly similar.
  
  
  CONCLUSIONS
  We suggest that SP-A and ACE are promising early biochemical markers for the development for pulmonary edema formation in the ex vivo lung lobe perfusion.
authors.affiliation: Institut für Pharmazie und Lebensmittelchemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
authors.forename: Mirjam
authors.initials: M
authors.lastname: Gnadt
authors.forename: Boris
authors.initials: B
authors.lastname: Kardziev
authors.forename: Michael
authors.initials: M
authors.lastname: Schmidt
authors.forename: Petra
authors.initials: P
authors.lastname: Högger
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D006801:Humans; D008168:Lung / Q000378:metabolism* / Q000601:surgery; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D010477:Perfusion; D011013:Pneumonectomy; D011654:Pulmonary Edema / Q000175:diagnosis* / Q000378:metabolism*; D037662:Pulmonary Surfactant-Associated Protein A / Q000378:metabolism*; D012121:Respiration, Artificial; D013997:Time Factors
chemical_list: D015415:Biomarkers; D037662:Pulmonary Surfactant-Associated Protein A; D007703:Peptidyl-Dipeptidase A