Metabolic precursors of surfactant disaturated-phosphatidylcholine in preterms with respiratory distress.
Our objective was to study the metabolic precursors of surfactant disaturated-phosphatidylcholine (DSPC) in preterm infants with respiratory distress syndrome (RDS) on mechanical ventilation. We performed 46 DSPC kinetic studies in 23 preterms on fat-free parenteral nutrition and mechanical ventilation (birth weight = 1167 +/- 451 g, gestational age = 28.5 +/- 2.0 weeks). Eight infants received a simultaneous intravenous infusion of U(13)C-glucose and [16,16,16](2)H-palmitate, eight infants received U(13)C-glucose and (2)H(2)O, and seven received U(13)C-palmitate and (2)H(2)O. Surfactant DSPC kinetics were calculated from the isotopic enrichments of DSPC-palmitate from sequential tracheal aspirates and its metabolic precursors in plasma or urine. DSPC fractional synthesis rate (FSR) was 17 +/- 11, 21 +/- 16, and 15 +/- 6%/day from glucose, palmitate, and body water, respectively (P = 0.36). DSPC-FSR from U(13)C-glucose and (2)H(2)O were significantly correlated and yielded similar estimates (difference of -0.1 +/- 3%) (P = 0.91). The difference in the 15 infants receiving palmitate versus (2)H(2)O or palmitate versus glucose was +6.0 +/- 12%/day (P = 0.21). There was a significant correlation between DSPC-FSRs from plasma glucose and plasma FFA. The contribution of glucose versus palmitate to DSPC-FSR was 49 +/- 20% versus 51 +/- 20%, respectively. Plasma glucose and FFA showed similar contributions to DSPC-FSR in infants with RDS and fat-free parenteral nutrition. FSRs from (2)H(2)O or glucose were highly correlated.
Cogo
Paola E
PE
Department of Pediatrics, University of Padova, Padova, Italy. cogo@pediatria.unipd.it
Ori
Carlo
C
Simonato
Manuela
M
Verlato
Giovanna
G
Isak
Ilena
I
Hamvas
Aaron
A
Carnielli
Virgilio P
VP
D000704:Analysis of Variance; D001786:Blood Glucose / Q000378:metabolism; D002247:Carbon Isotopes; D002849:Chromatography, Gas; D003903:Deuterium; D005865:Gestational Age; D005947:Glucose / Q000008:administration & dosage; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007262:Infusions, Intravenous; D007700:Kinetics; D013058:Mass Spectrometry; D010168:Palmitates / Q000008:administration & dosage / Q000097:blood / Q000652:urine; D010713:Phosphatidylcholines / Q000378:metabolism*; D011663:Pulmonary Surfactants / Q000378:metabolism*; D012121:Respiration, Artificial; D012127:Respiratory Distress Syndrome, Newborn / Q000378:metabolism* / Q000628:therapy; D013997:Time Factors; D014867:Water / Q000008:administration & dosage / Q000378:metabolism
D001786:Blood Glucose; D002247:Carbon Isotopes; D010168:Palmitates; D010713:Phosphatidylcholines; D011663:Pulmonary Surfactants; C017463:lecithins, disaturated; D014867:Water; D003903:Deuterium; D005947:Glucose