< em > In utero < /em > ventilation induces lung parenchymal and vascular alterations in extremely preterm fetal sheep

Am J Physiol Lung Cell Mol Physiol. 2024 Jan 22. doi: 10.1152/ajplung.00249.2023. Online ahead of print.ABSTRACTExtremely preterm infants are often exposed to long durations of mechanical ventilation to facilitate gas exchange, resulting in ventilation-induced lung injury (VILI). New lung protective strategies utilising non-invasive ventilation or low tidal volumes are now common but have not reduced rates of bronchopulmonary dysplasia. We aimed to determine the effect of 24 hours of low tidal volume ventilation on the immature lung by ventilating preterm fetal sheep in utero. Preterm fetal sheep at 110 ± 1(SD) days gestation underwent sterile surgery for instrumentation with a tracheal loop to enable in utero mechanical ventilation (IUV). At 112 ± 1d gestation, fetuses received either in utero mechanical ventilation (IUV; n=10) targeting 3-5 mL/kg for 24 h, or no ventilation (CONT, n=9). At post-mortem, fetal lungs were collected to assess molecular and histological markers of lung inflammation and injury. IUV significantly increased lung mRNA expression of interleukin (IL)-1β, IL-6, IL-8, IL-10 and TNF compared with CONT, and increased surfactant protein (SP)-A1, SP-B and SP-C mRNA expression compared with CONT. IUV produced modest structural changes to the airways, including reduced parenchymal collagen and myofibroblast density. IUV increased pulmonary arteriole thickness compared to CONT but did not alter overall elastin or collagen content within the vasculature. In ...
Source: American Journal of Physiology. Lung Cellular and Molecular Physiology - Category: Cytology Authors: Source Type: research