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Vitamin A protects the preterm lamb diaphragm against adverse effects of mechanical ventilation

Citation

Song, Y and Dahl, M and Leavitt, W and Alvord, J and Bradford, CY and Albertine, KH and Pillow, JJ, Vitamin A protects the preterm lamb diaphragm against adverse effects of mechanical ventilation, Frontiers in Physiology, 9 Article 1119. ISSN 1664-042X (2018) [Refereed Article]


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Copyright Statement

Copyright 2018 Song, Dahl, Leavitt, Alvord, Bradford, Albertine and Pillow. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/

DOI: doi:10.3389/fphys.2018.01119

Abstract

Background: Preterm infants are deficient in vitamin A, which is essential for growth and development of the diaphragm. Preterm infants often require mechanical ventilation (MV) for respiratory distress. In adults, MV is associated with the development of ventilation-induced diaphragm dysfunction and difficulty weaning from the ventilator. We assessed the impact of MV on the preterm diaphragm and the protective effect of vitamin A during MV.

Methods: Preterm lambs delivered operatively at ∼131 days gestation (full gestation: 150 days) received respiratory support by synchronized intermittent mandatory ventilation for 3 days. Lambs in the treated group received daily (24 h) enteral doses of 2500 IU/kg/day vitamin A combined with 250 IU/kg/day retinoic acid (VARA) during MV, while MV control lambs received saline. Unventilated fetal reference lambs were euthanized at birth, without being allowed to breathe. The fetal diaphragm was collected to quantify mRNA levels of myosin heavy chain (MHC) isoforms, atrophy genes, antioxidant genes, and pro-inflammatory genes; to determine ubiquitin proteasome pathway activity; to measure the abundance of protein carbonyl, and to investigate metabolic signaling.

Results: Postnatal MV significantly decreased expression level of the neonatal MHC gene but increased expression level of MHC IIx mRNA level (p < 0.05). Proteasome activity increased after 3 days MV, accompanied by increased MuRF1 mRNA level and accumulated protein carbonyl abundance. VARA supplementation decreased proteasome activity and FOXO1 signaling, down-regulated MuRF1 expression, and reduced reactive oxidant production.

Conclusion: These findings suggest that 3 days of MV results in abnormal myofibrillar composition, activation of the proteolytic pathway, and oxidative injury of diaphragms in mechanically ventilated preterm lambs. Daily enteral VARA protects the preterm diaphragm from these adverse effects.

Item Details

Item Type:Refereed Article
Keywords:BPD, VIDD, bronchopulmonary dysplasia, disuse atrophy, retinoids, retinol, ventilator-induced diaphragm dysfunction
Research Division:Biological Sciences
Research Group:Biochemistry and Cell Biology
Research Field:Signal Transduction
Objective Division:Health
Objective Group:Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:Respiratory System and Diseases (incl. Asthma)
UTAS Author:Song, Y (Dr Yong Song)
ID Code:133693
Year Published:2018
Deposited By:Menzies Institute for Medical Research
Deposited On:2019-07-06
Last Modified:2019-08-05
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