Surfactant protein A (SP-A) and angiotensin converting enzyme (ACE) as early biomarkers for pulmonary edema formation in ventilated human lung lobes.

Mirjam Gnadt, Boris Kardziev, Michael Schmidt, Petra Högger

Lung 2012 Aug

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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. 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. 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. 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.

Citation

Mirjam Gnadt, Boris Kardziev, Michael Schmidt, Petra Högger. Surfactant protein A (SP-A) and angiotensin converting enzyme (ACE) as early biomarkers for pulmonary edema formation in ventilated human lung lobes. Lung. 2012 Aug;190(4):431-40