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Updated: Feb 27, 2026
Isolation of Pulmonary Artery Smooth Muscle Cells from Neonatal Mice
Published on: October 19, 2013
Pulmonary vascular changes in extremely preterm sheep after intra-amniotic exposure to Ureaplasma parvum and
Monique G M Willems1,2,3, Matthew W Kemp4, Laura A Fast1
1Department of Pediatrics, Maastricht University Medical Center, Maastricht, The Netherlands.
Background:
Chorioamnionitis can induce pulmonary inflammation and promote bronchopulmonary dysplasia development, distinguished by alveolar simplification and impaired vascular growth. Chorioamnionitis is more common during the extremely preterm canalicular lung stage (crucial for vascular development); and increases the risk for subsequent sepsis. We hypothesized that single/combined exposure to chronic and/or acute inflammation induces pulmonary inflammatory responses and vascular changes.
Methods:
Ovine fetuses were intra-amniotically exposed to chronic Ureaplasma parvum (UP) at 24 days (d) before extreme preterm delivery at 94d (term 147d) and/or to lipopolysaccharide (LPS) 7 or 2d before delivery. Pulmonary inflammation, vascular remodeling and angiogenic factors were assessed.
Results:
LPS exposure increased CD3-positive and myeloperoxidase-positive cells. Combined UP-LPS exposure increased pulmonary inflammation compared with 2d LPS or UP groups. The UP+2d LPS group had an increased adventitial fibrosis score when compared with UP-treated animals. A reduced wall-to-lumen ratio was found in the 7d LPS animals when compared to the 2d LPS-treated animals. Exposure to UP+2d LPS reduced VEGF and VEGFR-2 levels compared with 2d LPS-treated animals. Angiopoietin-1 (Ang1) and tunica interna endothelial cell kinase 2 (Tie-2) levels were decreased after UP+7d LPS as well as after 7d LPS, but not with UP alone.
Conclusion:
Chronic UP and subsequent LPS exposure increased pulmonary inflammation and decreased expression of angiogenic growth factors and receptors when compared to single hit-exposed animals.
