Amniotic fluid phosphatidylglycerol: an early indicator of fetal lung maturity

Quantitative lipidomic analysis of mouse lung during postnatal development by electrospray ionization tandem mass spectrometry

Lipids play very important roles in lung biology, mainly reducing the alveolar surface tension at the air-liquid interface thereby preventing end-expiratory collapse of the alveoli. In the present study we performed an extensive quantitative lipidomic analysis of mouse lung to provide the i) total lipid quantity, ii) distribution pattern of the major lipid classes, iii) composition of individual lipid species and iv) glycerophospholipid distribution pattern according to carbon chain length (total number of carbon atoms) and degree of unsaturation (total number of double bonds). We analysed and quantified 160 glycerophospholipid species, 24 sphingolipid species, 18 cholesteryl esters and cholesterol from lungs of a) newborn (P1), b) 15-day-old (P15) and c) 12-week-old adult mice (P84) to understand the changes occurring during postnatal pulmonary development. Our results revealed an increase in total lipid quantity, correlation of lipid class distribution in lung tissue and significant changes in the individual lipid species composition during postnatal lung development. Interestingly, we observed significant stage-specific alterations during this process. Especially, P1 lungs showed high content of monounsaturated lipid species; P15 lungs exhibited myristic and palmitic acid containing lipid species, whereas adult lungs were enriched with polyunsaturated lipid species. Taken together, our study provides an extensive quantitative lipidome of the postnatal mouse lung development, which may serve as a reference for a better understanding of lipid alterations and their functions in lung development and respiratory diseases associated with lipids.

Pregnancy-related factors and diseases influencing surfactant

Obstetric complications have been associated with accelerated fetal lung maturity. In a prospective study involving 189 babies born before 36 weeks no specific obstetric complication was observed to have a significant influence on neonatal respiratory function. In addition fetal stress factors did not seem to contribute to eventual outcome.

Maternal diabetes and neonatal respiratory distress. II. Prediction of fetal lung maturity

Fifty babies were born at less than or equal to 37 weeks to mothers with diabetes. Delivery was undertaken in all patients with the reassurance that the L/S ratio was greater than or equal to 2.0 within the preceding 72 h. Five babies (10%) developed respiratory distress syndrome (RDS). Prediction of fetal lung maturity was improved dramatically by measuring amniotic fluid concentrations of phosphatidylcholine (PC), phosphatidylinositol (PI) and phosphatidylglycerol (PG). Fourteen babies were predicted as having 'no surfactant' (PC less than 20 mg/l, PI less than 2 mg/l and PG less than 2 mg/l), five developed RDS. None of the remaining 36 babies developed the illness: they were predicted as having either 'early surfactant' (PC greater than or equal to 20 mg/l, PI greater than or equal to 2 mg/l but PG less than 2 mg/l) or 'late surfactant' (PC greater than or equal to 20 mg/l, PI greater than or equal to 2 mg/l and PG greater than or equal to 2 mg/l). Measurement of PC levels alone was the most was the most accurate method of predicting RDS. There was a significant association between low surfactant phospholipid concentrations and the development of transient tachypnoea of the newborn.