The Truncated Splice Variant of the Granulocyte-Macrophage-Colony-Stimulating Factor Receptor ß- Chain in Peripheral Blood Serves as Severity Biomarker of Respiratory Failure in Newborns.

BACKGROUND: The granulocyte-macrophage-colony-stimulating factor (GM-CSF) plays an important role in surfactant homeostasis. ßC is a subunit of the GM-CSF receptor (GM-CSF-R), and its activation mediates surfactant catabolism in the lung. ßIT is a physiological, truncated isoform of ßC and is known to act as physiological inhibitor of ßC. OBJECTIVE: The aim of this study was to determine the ratio of ßIT and ßC in the peripheral blood of newborns and its association with the degree of respiratory failure at birth. METHODS: We conducted a prospective cohort study in newborns with various degrees of respiratory impairment at birth. Respiratory status was assessed by a score ranging from no respiratory impairment (0) to invasive respiratory support (3). ßIT and ßC expression were determined in peripheral blood cells by real-time PCR. ßIT expression, defined as the ratio of ßIT and ßC, was correlated with the respiratory score. RESULTS: ßIT expression was found in all 59 recruited newborns with a trend toward higher ßIT in respiratory ill (score 2, 3) newborns than respiratory healthy newborns ([score 0, 1]; p = 0.066). Seriously ill newborns (score 3) had significantly higher ßIT than healthy newborns ([score 0], p = 0.010). Healthy preterm infants had significantly higher ßIT expression than healthy term infants (p = 0.019). CONCLUSIONS: ßIT is expressed in newborns with higher expression in respiratory ill than respiratory healthy newborns. We hypothesize that ßIT may have a protective effect in postnatal pulmonary adaptation acting as a physiological inhibitor of ßC and, therefore, maintaining surfactant in respiratory ill newborns.

Sonographic assessment of abdominal fat distribution during the first year of infancy.

BACKGROUND: Longitudinal data regarding the fat distribution in the early postnatal period is sparse. METHODS: We performed ultrasonography (US) as a noninvasive approach to investigate the development of abdominal subcutaneous (SC) and preperitoneal (PP) fat depots in infants ≤1 y and compared longitudinal US data with skinfold thickness (SFT) measurements and anthropometry in 162 healthy children at 6 wk, 4 mo, and 1 y postpartum. RESULTS: US was found to be a reproducible method for the quantification of abdominal SC and PP adipose tissue (AT) in this age group. Thickness of SC fat layers significantly increased from 6 wk to 4 mo and decreased at 1 y postpartum, whereas PP fat layers continuously increased. Girls had a significantly higher SC fat mass compared to boys, while there was no sex-specific difference in PP fat thickness. SC fat layer was strongly correlated with SFT measurements, while PP fat tissue was only weakly correlated with anthropometric measures. CONCLUSION: US is a feasible and reproducible method for the quantification of abdominal fat mass in infants ≤1 y of age. PP and SC fat depots develop differentially during the first year of life.