期刊
AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE
卷 178, 期 4, 页码 399-406出版社
AMER THORACIC SOC
DOI: 10.1164/rccm.200711-1631OC
关键词
hyperoxia; lung injury; gene therapy; potassium channels; bronchopulmonary dysplasia
资金
- Canadian Institutes of Health Research (CIHR)
- Alberta Heritage Foundation for Medical Research (AHFMR)
- Heart and Stroke Foundation Canada
- Canada Foundation for Innovation (CFI)
- Canada Research Chair in Translation Lung and Vascular Developmental Biology
- NIH [HL071115]
- CA
- Maternal Fetal Neonatal Health Training Program
- CIHR-IHDCYH
- March of Dimes Birth Defects Foundation [6-FY97-01 38]
- NHLBI [HL-62512, HL-62875]
Rationale: Neonatal chronic lung disease (CLD), caused by prolonged mechanical ventilation (MV) with O(2)-rich gas, is the most common cause of long-term hospitalization and recurrent respiratory illness in extremely premature infants. Recurrent episodes of hypoxemia and associated ventilator adjustments often lead to worsening CLD. The mechanism that causes these hypoxemic episodes is unknown. Hypoxic pulmonary vasoconstriction (HPV), which is partially controlled by O(2)-sensitive voltage-gated potassium (K(v)) channels, is an important adaptive response to local hypoxia that helps to match perfusion and ventilation in the lung. Objectives: To test the hypothesis that chronic lung injury (CLI) impairs HPV. Methods: We studied preterm lambs that had MV with O(2)-rich gas for 3 weeks and newborn rats that breathed 95%-O(2) for 2 weeks, both of which resulted in airspace enlargement and pulmonary vascular changes consistent with CLD. Measurements and Main Results: HPV was attenuated in preterm lambs with CLI after 2 weeks of MV and in newborn rats with CLI after 2 weeks of hyperoxia. HPV and constriction to the K(v)1.x-specific inhibitor, correolide, were preferentially blunted in excised distal pulmonary arteries (dPAs) from hyperoxic rats, whose dPAs exhibited decreased K(v)1.5 and K(v)2.1 mRNA and K(+) current. Intrapulmonary gene transfer of K(v)1.5, encoding the ion channel that is thought to trigger HPV, increased O(2)-sensitive K(+) current in cultured smooth muscle cells from rat dPAs, and restored HPV in hyperoxic rats. Conclusions: Reduced expression/activity of O(2)-sensitive K(v) channels in dPAs contributes to blunted HPV observed in neonatal CLD.
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