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Resistance of different surfactant preparations to inactivation by meconium
E Herting1, P Rauprich, G Stichtenoth
1Department of Pediatrics, University of Göttingen, D-37075 Göttingen, Germany. eherting@med.uni-goettingen.de
Abstract:
A disease similar to acute respiratory distress syndrome may occur in neonates after aspiration of meconium. The aim of the study was to compare the inhibitory effects of human meconium on the following surfactant preparations suspended at a concentration of 2.5 mg/mL: Curosurf, Alveofact, Survanta, Exosurf, Pumactant, rabbit natural surfactant from bronchoalveolar lavage, and two synthetic surfactants based on recombinant surfactant protein-C (Venticute) or a leucine/lysine polypeptide. Minimum surface tension, determined with a pulsating bubble surfactometer, was increased >10 mN/m at meconium concentrations >or=0.04 mg/mL for Curosurf, Alveofact, or Survanta, >or=0.32 mg/mL for recombinant surfactant protein-C, >or=1.25 mg/mL for leucine/lysine polypeptide, and >or=20 mg/mL for rabbit natural surfactant. The protein-free synthetic surfactants Exosurf and Pumactant did not reach minimum surface tension <10 mN/m even in the absence of meconium. We conclude that surfactant activity is inhibited by meconium in a dose-dependent manner. Recombinant surfactant protein-C and leucine/lysine polypeptide surfactant were more resistant to inhibition than the modified natural surfactants Curosurf, Alveofact, or Survanta but less resistant than natural lavage surfactant containing surfactant protein-A. We speculate that recombinant hydrophobic surfactant proteins or synthetic analogs of these proteins can be used for the design of new surfactant preparations that are relatively resistant to inactivation and therefore suitable for treatment of acute respiratory distress syndrome.
Insights
Human meconium inhibits surfactant activity in a dose-dependent manner, impacting neonatal respiratory distress. Certain synthetic surfactants show greater resistance to this inhibition, suggesting potential for improved treatments.
Area of Science:
- Neonatal Medicine
- Pulmonary Physiology
- Biochemistry
Background:
- Meconium aspiration in neonates can lead to a severe lung condition resembling acute respiratory distress syndrome.
- Pulmonary surfactant is crucial for maintaining lung function, and its dysfunction contributes to respiratory distress.
Purpose of the Study:
- To compare the inhibitory effects of human meconium on various surfactant preparations.
- To evaluate the resistance of different surfactant types to meconium-induced inactivation.
Main Methods:
- Assessed minimum surface tension of surfactant preparations using a pulsating bubble surfactometer.
- Tested inhibitory effects of human meconium at varying concentrations (≥0.04 mg/mL) on Curosurf, Alveofact, Survanta, Exosurf, Pumactant, rabbit natural surfactant, recombinant protein-C surfactant, and leucine/lysine polypeptide surfactant.
- Determined minimum surface tension values in the presence and absence of meconium.
Main Results:
- Meconium increased minimum surface tension (>10 mN/m) in a dose-dependent manner for most surfactants.
- Surfactant protein-C and leucine/lysine polypeptide surfactants demonstrated higher resistance to meconium inhibition compared to modified natural surfactants.
- Protein-free synthetic surfactants (Exosurf, Pumactant) failed to achieve low surface tension even without meconium.
Conclusions:
- Meconium significantly inhibits surfactant activity, with varying degrees of resistance among different preparations.
- Synthetic surfactants incorporating recombinant hydrophobic proteins or their analogs may offer improved resistance to meconium inactivation.
- These findings suggest potential for developing novel surfactant therapies for neonatal respiratory distress caused by meconium aspiration.