Liver, Not Only Lungs, Impacted by High Levels of Oxygen
Findings Could Have Implications for Prematurity and BPD
A study from Nationwide Children’s Hospital is the first to show that exposure to higher-than-normal levels of oxygen can affect the liver in a neonatal animal model. These findings, which appear in Pediatric Research, could indicate new opportunities for research into human lung conditions including one of the most common chronic lung diseases in children, bronchopulmonary dysplasia (BPD).
Premature infants are often treated with oxygen and mechanical ventilation. Despite being essential, these oxygen therapies are associated with lung injury and the development of diseases such as BPD. BPD is characterized by inflammation and scarring in the lungs. Injury to a single organ has been shown to result in inflammation in other organs.
“Frequently, lung injury affects liver function and vice versa,” said Lynette Rogers, PhD, principal investigator in the Center for Perinatal Research, The Research Institute at Nationwide Children’s Hospital. “The related responses between the lung and the liver are being actively studied in adults, but little is known about such a relationship in neonates.”
To further clarify the lung-liver relationship, faculty from Nationwide Children’s examined whether increased oxygen exposure stresses the liver in a neonatal model. Newborn mice were exposed either to room air or higher levels of oxygen for 14 days, after which their lung and liver tissues were analyzed.
Results showed that early responses to high levels of oxygen were primarily oxidant in the lung, while alterations in lipid metabolism were common in the liver. Mice exposed to high levels of oxygen had increased levels of lipid metabolites in their livers which occurred earlier than similar responses in lung tissues
“Our findings demonstrate that different mechanisms mediate responses to hyperoxic exposure in newborn and adult mice and that in this newborn model, oxidant stresses are mechanistically important,” said Dr. Rogers, one of the study authors. “This study identifies possible new mechanisms associated with hyperoxic lung injury in a newborn model of BPD.”
Further study is needed to determine whether the metabolites overproduced in the liver could be secreted into circulation and contribute to the observed lung inflammation and delayed lung growth observed.
Rogers LK, Tipple TE, Britt RD, Welty SE. Hyperoxia Exposure Alters Hepatic Eicosanoid Metabolism in Newborn Mice. Pediatr Res. 2009 Oct 5. [Epub ahead of print]
