Phosphatidylcholine molecular species in lung surfactant: composition in relation to respiratory rate and lung development.
Surfactant reduces surface tension at the air-liquid interface of lung alveoli. While dipalmitoylphosphatidylcholine (PC16:0/ 16:0) is its main component, proteins and other phospholipids contribute to the dynamic properties and homeostasis of alveolar surfactant. Among these components are significant amounts of palmitoylmyristoylphosphatidylcholine (PC16:0/ 14:0) and palmitoylpalmitoleoylphosphatidylcholine (PC16:0/ 16:1), whereas in surfactant from the rigid tubular bird lung, PC16:0/14:0 is absent and PC16:0/16:1 strongly diminished. We therefore hypothesized that the concentrations of PC16:0/14:0 and PC16:0/16:1 in surfactants correlate with differences in the respiratory physiology of mammalian species. In surfactants from newborn and adult mice, rats, and pigs, molar fractions of PC16:0/14:0 and PC16:0/16:1 correlated with respiratory rate. Labeling experiments with [methyl-(3)H]choline in mice and perfused rat lungs demonstrated identical alveolar proportions of total and newly synthesized PC16:0/14:0, PC16:0/16:1, and PC16:0/16:0, which were much higher than those of other phosphatidylcholine species. In surfactant from human term and preterm neonates, fractional concentrations not only of PC16:0/16:0 but also of PC16:0/14:0 and PC16:0/ 16:1 increased with maturation. Our data emphasize that PC16:0/14:0 and PC16:0/16:1 may be important surfactant components in alveolar lungs, and that their concentrations are adapted to respiratory physiology.
Bernhard
W
W
Department of Pediatric Pulmonology, Hannover Medical School, Hannover, Germany. bernhard.wolfgang@mh-hannover.de
Hoffmann
S
S
Dombrowsky
H
H
Rau
G A
GA
Kamlage
A
A
Kappler
M
M
Haitsma
J J
JJ
Freihorst
J
J
von der Hardt
H
H
Poets
C F
CF
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000031:analogs & derivatives / Q000032:analysis; D000375:Aging / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D001992:Bronchoalveolar Lavage Fluid; D002645:Chickens; D002794:Choline / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid; D004372:Ducks; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008168:Lung / Q000196:embryology / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D010713:Phosphatidylcholines / Q000032:analysis* / Q000737:chemistry / Q000145:classification; D011663:Pulmonary Surfactants / Q000737:chemistry*; D051381:Rats; D012119:Respiration; D013045:Species Specificity; D013047:Specific Pathogen-Free Organisms; D013500:Surface Tension; D013552:Swine
C445666:1-palmitoyl-2-myristoylphosphatidylcholine; D010713:Phosphatidylcholines; D011663:Pulmonary Surfactants; D015060:1,2-Dipalmitoylphosphatidylcholine; C033036:1-palmitoyl-2-palmitoleoyl-sn-glycero-3-phosphocholine; D002794:Choline