Background and aims Despite advances in ventilation support, acute lung disease (ALD) remains the leading cause of morbidity, mortality, and disability after preterm birth. There is a need for a spontaneous translational model of ALD after preterm birth.
Methods Preterm pigs delivered at gestation days (GD) 98, 100, 102, and 104 days were provided ventilation support using supplemental oxygen (NC), bubble Continuous Positive Airway Pressure (bCPAP; 7–8 cm H2O), or mechanical ventilation (MV; Pressure Control Ventilation with Volume Guarantee; 5 ml/kg; PEEP 5 cm H2O). Monitoring included pulse oximetry, arterial blood gases, and radiography. Lungs were harvested after 24 h or after premature death for histology and measurements of surfactant protein B, phosphatidylcholine, and cytokines.
Results All pigs breathed spontaneously. Lungs at GD 98 and 100 were consolidated with immature alveolar architecture, minimal surfactant protein B expression, and MV was essential for 24 h survival. GD 102 pigs had alveoli lined by pneumocytes and surfactant was released in response to MV. Blood gases and radiography for NC and bCPAP pigs 1–2 h after delivery revealed limited recruitment and mortality at 24 h was 66% (35/53) and 69% (9/13), respectively. GD 104 pigs had higher densities of thin walled alveoli that secreted surfactant and MV was not essential.
Conclusions Preterm pigs have developmental changes in ventilation inadequacies that mimic those of preterm infants and represent a spontaneous model of ALD that is clinically relevant, compatible with standards of chronic neonatal intensive care, and is an alternative for nonhuman primates and lambs.