Differences in surfactant lipids collected from pleural and pulmonary lining fluids.
OBJECTIVE
The type and relative importance of saturated and unsaturated phospholipid components of surfactant within the epithelial lining fluid (ELF) of the inner and outer surfaces of the lung is not known.


METHODS
Seven healthy dogs were anesthetized and a bronchoalveolar lavage (BAL) was performed, immediately followed by a pleural lavage (PL). Lipid was extracted from lavage fluid and then analyzed for saturated, primarily dipalmitoylphosphatidylcholine (DPPC), and unsaturated phosphatidylcholine (PC) species using high-performance liquid chromatography (HPLC) with combined fluorescence and ultraviolet detection. Dilution of ELF in lavage fluids was corrected for using the urea method.


RESULTS
DPPC (494.7 +/- 213.9 microg/mL) was the predominant PC present in ELF collected from the alveolar surface. In contrast, significantly higher (p = 0.028) proportions of unsaturated PC species were measured in PL fluid (approximately 105 microg/mL), particularly stearoyl-linoleoyl-phosphatidylcholine (SLPC), which could not be measured in fluid collected from the alveoli, compared to DPPC (2.6 +/- 2.0 microg/mL).


CONCLUSIONS
This study indicates that unsaturated PC species seem to be more important than saturated species, particularly DPPC, in the pleural cavity, which has implications for surfactant replenishment following pleural disease or thoracic surgery.
Mills
Paul C
PC
School of Veterinary Science, University of Queensland, Brisbane, Queensland 4072, Australia. p.mills@uq.edu.au
Chen
Yi
Y
Hills
Yvette C
YC
Hills
Brian A
BA
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000032:analysis; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D004285:Dogs; D005260:Female; D008297:Male; D010743:Phospholipids / Q000032:analysis*; D010994:Pleura / Q000737:chemistry*; D011663:Pulmonary Surfactants / Q000032:analysis*
D010743:Phospholipids; D011663:Pulmonary Surfactants; D015060:1,2-Dipalmitoylphosphatidylcholine