Hyperoxia Disrupts Lung Lymphatic Homeostasis in Neonatal Mice.

Area of Science:

• Neonatal physiology
• Vascular biology
• Pulmonary medicine

Background:

• Bronchopulmonary dysplasia (BPD) is a prevalent lung disease in preterm infants, often driven by inflammation.
• Limited understanding of inflammatory mechanisms in developing lungs hinders BPD therapy development.
• Lymphatic vessels are crucial regulators of immune homeostasis and inflammation.

Purpose of the Study:

• To investigate the impact of hyperoxia (HO), a major BPD risk factor, on lymphatic endothelial homeostasis.
• To characterize the lymphatic phenotype in an experimental BPD model.
• To identify molecular mechanisms by which HO affects lymphatic development and function.

Main Methods:

• Utilized neonatal mice and human dermal lymphatic endothelial cells (HDLECs) exposed to hyperoxia (70% O2).
• Assessed gene expression of key lymphatic markers (Prox1, Vegf-c) and cellular functions (tubule formation).
• Quantified lymphatic vessel density and function in neonatal murine lungs post-HO exposure.

Main Results:

• HO exposure decreased Prox1 and Vegf-c expression and impaired tubule formation in HDLECs.
• HO attenuated the physiological increase of Prox1 and Vegf-c mRNA in neonatal murine lungs.
• HO reduced lymphatic vessel density and lymphatic function in neonatal lungs.

Conclusions:

• Hyperoxia disrupts lymphatic endothelial homeostasis, impacting lymphatic development and function.
• These findings validate the hypothesis that HO negatively affects lymphatic function in the context of BPD.
• Understanding HO's effect on lymphatics offers potential therapeutic strategies for BPD.