Genetic Regulation of Surfactant Deficiency
- Conditions
- Respiratory Distress Syndrome, Newborn
- Interventions
- Drug: Nutrient
- Registration Number
- NCT00828243
- Lead Sponsor
- Washington University School of Medicine
- Brief Summary
Inherited deficiencies in any one of 3 genes (surfactant protein B, surfactant protein C, and ATP-binding cassette transporter A3) can cause neonatal respiratory distress syndrome by disrupting metabolism of the pulmonary surfactant. The investigators will use state of the art methods to link specific changes in the genetic code of each of these genes with disruption of discrete steps in the metabolism of the pulmonary surfactant in human newborn infants. These studies will lead to improved diagnostic capabilities and suggest novel strategies to correct surfactant deficiency in newborn infants.
- Detailed Description
Genetic regulation of neonatal pulmonary surfactant deficiency has been suggested by studies of gender, genetic linkage, recurrent familial cases, targeted gene ablation in murine lineages, and by racial disparity in risk of neonatal respiratory distress syndrome. Successful fetal-neonatal pulmonary transition requires production of the pulmonary surfactant, a phospholipid-protein film that lines alveoli and maintains alveolar patency at end expiration. Our goal is to understand the genetic mechanisms that disrupt pulmonary surfactant metabolism and cause neonatal respiratory distress syndrome. Studies in human newborn infants have demonstrated that 3 genes are critical for surfactant metabolism: surfactant protein B (SFTPB), surfactant protein C (SFTPC), and an ATP-binding cassette transporter, ABCA3 (ABCA3). To understand genetic regulatory mechanisms, we will investigate the contribution of variation in each of these genes to risk of neonatal respiratory distress syndrome by testing the hypothesis that genetic variants in the SFTPB, SFTPC, and ABCA3 disrupt pulmonary surfactant metabolism. Using high throughput automated sequencing to genotype, multidimensional protein identification technology to assess quantitative and qualitative differences in surfactant protein B and C expression, in vivo metabolic labeling with stable isotopically labeled precursors to estimate surfactant protein B and C and phospholipid metabolic rates, and cohort sizes that provide statistical power (0.8), we will use race-specific, severity-stratified case-control (N=480) and case comparison (N=250) designs to understand genetically regulated, metabolic mechanisms that cause surfactant deficiency by disrupting expression or altering processing of surfactant proteins B or C or by disrupting surfactant phospholipid composition in human newborn infants. Improved understanding of genetic regulation of surfactant deficiency will suggest novel diagnostic strategies to identify and categorize high risk infants and therapeutic strategies that target discrete steps in pulmonary surfactant metabolism to improve outcomes of infants with neonatal respiratory distress syndrome.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 525
- Newborn infants with respiratory distress syndrome who require mechanical ventilation via endotracheal tube or tracheostomy in the first 6 months of life
- Infants with conditions likely to cause imminent death
Study & Design
- Study Type
- OBSERVATIONAL
- Study Design
- Not specified
- Arm && Interventions
Group Intervention Description Nutrient Nutrient To newborn infants with respiratory distress syndrome, we administer stable isotopically labeled nutrients (precursors of surfactant phospholipids or proteins) to permit mass spectrometry-based comparison of surfactant phospholipid and protein turnover.
- Primary Outcome Measures
Name Time Method Association of specific variants or interactions among variants in SFTPB, SFTPC, and ABCA3 with neonatal respiratory distress syndrome 1 week Statistical association of increased risk of neonatal respiratory distress in term or near term infants with specific genomic variants in SFTPB, SFTPC, and ABCA3
- Secondary Outcome Measures
Name Time Method Association of specific variants or interactions among variants in SFTPB, SFTPC, and ABCA3 with fractional synthetic rate and/or fractional catabolic rate of surfactant phospholipids, surfactant protein-B, and surfactant protein-C 1 week Statistical association of quantitative surfactant phospholipid metabolic characteristics with specific genomic variants in SFTPB, SFTPC, and ABCA3
Trial Locations
- Locations (1)
St. Louis Children's Hospital
🇺🇸Saint Louis, Missouri, United States