Surfactant protein C metabolism in human infants and adult patients by stable isotope tracer and mass spectrometry

Manuela Simonato, Aldo Baritussio, Barbara Pioselli, Carlo Ori, Silvia Catinella, Virgilio P. Carnielli, Paola E. Cogo

Research output: Contribution to journalArticlepeer-review


Surfactant protein C (SP-C) is deemed as the surfactant protein most specifically expressed in type II alveolar epithelial cells and plays an important role in surfactant function. SP-C turnover in humans and its meaning in the clinical context have never been approached. In this study, we used mass spectrometry to investigate SP-C turnover in humans. We studied four infants and eight adults requiring mechanical ventilation. All patients had no lung disease. Patients received a 24-h continuous infusion of 13C-leucine as precursor of SPC, and serial tracheal aspirates and plasma samples were obtained every 6 h till 48 h. SP-C was isolated from tracheal aspirates by sorbent-phase chromatography. 13C-leucine SP-C enrichment could be successfully measured in three infant and in four adult samples by using mass spectrometry coupled with a gas chromatographer. Median SP-C fractional synthesis rate, secretion time, and peak time were 15.7 (14.1-27.5) %/ day, 6.0 (4.7-11.5) h, and 24 (20-27) h. In conclusion, this study shows that it is feasible to accurately determine SP-C turnover in humans by stable isotopes.

Original languageEnglish
Pages (from-to)6225-6233
Number of pages9
JournalAnalytical and Bioanalytical Chemistry
Issue number25
Publication statusPublished - Jan 1 2014


  • Isotope
  • Lung surfactant
  • Mass spectrometry
  • Surfactant protein C

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Medicine(all)


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