Taking a Cooler Breath: Moderate Hypothermia Boosts Lung Surfactant Activity

Reducing temperature to values close to lung surfactant melting point may improve the dynamic interfacial properties of the system. in this work, we have analysed the temperature-mediated enhancement of the interfacial performance of purified porcine surfactant (PS) under plasma inhibition in a Constrained Drop Surfactometer. We have also explored the temperature-related rescue of surfactant performance. To do so, the drop interface was previously covered by plasma and PS until impairing surfactant dynamic properties. Synthetic lipid/protein mixtures or Poractant alfa were then dispensed at the air-liquid interface during compression-expansion cycles of the drop. All experiments were performed at both physiological (37 °C) and therapeutic hypothermia (33 °C) temperatures.The lower the concentration of tested material, the greater the capability of surfactant to reduce surface tension at 33 °C compared with 37 °C. At therapeutic hypothermia temperature, surfactant resistance to plasma inhibition is improved and restoration therapies are more effective regardless of the applied material. These in vitro results help to explain the good respiratory outcomes of cooled patients with direct acute respiratory distress syndrome and suggest new treatments for acute lung injury.