Metabolic precursors of surfactant disaturated-phosphatidylcholine in preterms with respiratory distress

Paola E Cogo,Carlo Ori,Manuela Simonato,Giovanna Verlato,Ilena Isak,Aaron Hamvas,Virgilio P Carnielli

doi:10.1194/jlr.m800514-jlr200

Paola E Cogo, Carlo Ori + Show 5 more

Open Access

https://doi.org/10.1194/jlr.m800514-jlr200

Copy DOI

Abstract

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.

Highlights

Our objective was to study the metabolic precursors of surfactant disaturated-phosphatidylcholine (DSPC) in preterm infants with respiratory distress syndrome (RDS) on mechanical ventilation
The alveolar type II cell is the primary site of synthesis, storage, and secretion of pulmonary surfactant that consists of a mixture of lipids and proteins that are highly enriched with dipalmitoyl-phosphatidylcholine (DPPC) and other phospholipids with saturated fatty acids in the one and two position of the glycerol moiety [1,2,3]
Energy intake in the 3 groups is reported in Table 1. i.v. lipids and minimal enteral feeding were started after 96 h of life according with the nutritional policy of the neonatal unit when the study was performed

Summary

Introduction

Our objective was to study the metabolic precursors of surfactant disaturated-phosphatidylcholine (DSPC) in preterm infants with respiratory distress syndrome (RDS) on mechanical ventilation. Plasma glucose and FFA showed similar contributions to DSPC-FSR in infants with RDS and fatfree parenteral nutrition. The alveolar type II cell is the primary site of synthesis, storage, and secretion of pulmonary surfactant that consists of a mixture of lipids and proteins that are highly enriched with dipalmitoyl-phosphatidylcholine (DPPC) and other phospholipids with saturated fatty acids in the one and two position of the glycerol moiety [1,2,3]. The relative contribution of each of the potential sources of FA (glucose, acetate, lactate, and FFA) for incorporation into the lung surfactant disaturated-phosphatidylcholine (DSPC) has been studied in animals by radioactive and, more recently, stable isotopes tracers [4, 9,10,11,12,13].

Objectives

Methods

Results

Conclusion