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Ke X, Xia S, Yu W, Mabry S, Fu Q, Menden HL, Sampath V, Lane RH. Delta like 4 regulates cerebrovascular development and endothelial integrity via DLL4-NOTCH-CLDN5 pathway and is vulnerable to neonatal hyperoxia. J Physiol 2024. [PMID: 38632887 DOI: 10.1113/jp285716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 03/19/2024] [Indexed: 04/19/2024] Open
Abstract
The mechanisms governing brain vascularization during development remain poorly understood. A key regulator of developmental vascularization is delta like 4 (DLL4), a Notch ligand prominently expressed in endothelial cells (EC). Exposure to hyperoxia in premature infants can disrupt the development and functions of cerebral blood vessels and lead to long-term cognitive impairment. However, its role in cerebral vascular development and the impact of postnatal hyperoxia on DLL4 expression in mouse brain EC have not been explored. We determined the DLL4 expression pattern and its downstream signalling gene expression in brain EC using Dll4+/+ and Dll4+/LacZ mice. We also performed in vitro studies using human brain microvascular endothelial cells. Finally, we determined Dll4 and Cldn5 expression in mouse brain EC exposed to postnatal hyperoxia. DLL4 is expressed in various cell types, with EC being the predominant one in immature brains. Moreover, DLL4 deficiency leads to persistent abnormalities in brain microvasculature and increased vascular permeability both in vivo and in vitro. We have identified that DLL4 insufficiency compromises endothelial integrity through the NOTCH-NICD-RBPJ-CLDN5 pathway, resulting in the downregulation of the tight junction protein claudin 5 (CLDN5). Finally, exposure to neonatal hyperoxia reduces DLL4 and CLDN5 expression in developing mouse brain EC. We reveal that DLL4 is indispensable for brain vascular development and maintaining the blood-brain barrier's function and is repressed by neonatal hyperoxia. We speculate that reduced DLL4 signalling in brain EC may contribute to the impaired brain development observed in neonates exposed to hyperoxia. KEY POINTS: The role of delta like 4 (DLL4), a Notch ligand in vascular endothelial cells, in brain vascular development and functions remains unknown. We demonstrate that DLL4 is expressed at a high level during postnatal brain development in immature brains and DLL4 insufficiency leads to abnormal cerebral vasculature and increases vascular permeability both in vivo and in vitro. We identify that DLL4 regulates endothelial integrity through NOTCH-NICD-RBPJ-CLDN5 signalling. Dll4 and Cldn5 expression are decreased in mouse brain endothelial cells exposed to postnatal hyperoxia.
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Affiliation(s)
- Xingrao Ke
- Department of Pediatrics Division of Neonatology, Children's Mercy, Kansas City, MO, USA
| | - Sheng Xia
- Department of Pediatrics Division of Neonatology, Children's Mercy, Kansas City, MO, USA
| | - Wei Yu
- Department of Pediatrics Division of Neonatology, Children's Mercy, Kansas City, MO, USA
| | - Sherry Mabry
- Department of Pediatrics Division of Neonatology, Children's Mercy, Kansas City, MO, USA
| | - Qi Fu
- Department of Pediatrics Division of Neonatology, Children's Mercy, Kansas City, MO, USA
| | - Heather L Menden
- Department of Pediatrics Division of Neonatology, Children's Mercy, Kansas City, MO, USA
| | - Venkatesh Sampath
- Department of Pediatrics Division of Neonatology, Children's Mercy, Kansas City, MO, USA
| | - Robert H Lane
- Department of Administration, Children Mercy Research Institute, Children's Mercy, Kansas City, MO, USA
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Ekekezie I, O’Hanlon L, Mabry S. Neurotrophins expression is decreased in lungs of human infants with congenital diaphragmatic hernia. RRN 2014. [DOI: 10.2147/rrn.s53673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Truog WE, Xu D, Ekekezie II, Mabry S, Rezaiekhaligh M, Svojanovsky S, Soares MJ. Chronic hypoxia and rat lung development: analysis by morphometry and directed microarray. Pediatr Res 2008; 64:56-62. [PMID: 18344904 DOI: 10.1203/pdr.0b013e31817289f2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
It is unclear how sublethal hypoxia affects lung development. To investigate the effects of chronic hypoxia on postnatal lung remodeling, we treated neonatal rats with FIO2 of 0.12 for 10 d and analyzed lung development by morphometry and gene expression by DNA microarray. Our results showed the neonatal rats exposed to hypoxia reduced body weight by 42% and wet lung weight by 32% compared with the neonatal rats exposed to normoxia. In the neonatal rats exposed to hypoxia, the radial alveolar counts were decreased to 5.6 from 7.9 and the mean linear intercepts were increased to 56.5 mum from 38.2 mum. In DNA microarray analysis, approximately half of probed genes were unknown. Chronic hypoxia significantly regulated expression of genes that are involved in pathogenesis of pulmonary hypertension and postnatal lung remodeling. Chemokine ligand 12, jagged 2 were among those upregulated; c-kit, ephrin A1, and Hif-2alpha were among those downregulated. The altered expression of those genes was correlated with the lung development and remodeling.
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Affiliation(s)
- William E Truog
- Department of Pediatrics, Section of Neonatology, University of Missouri-Kansas City School of Medicine, Children's Mercy Hospitals and Clinics, Kansas City, Missouri 64108, USA.
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Olmo MAN, Xu D, Rezaiekhaligh M, Mabry S, Perez RE, Truog WE, Ekekezie II. Difference in the apoptotic response of fetal versus adult human lung fibroblasts in collagen gels. FASEB J 2007. [DOI: 10.1096/fasebj.21.5.a406-d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Maria A Navarro Olmo
- NeonatologyChildren's Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
| | - Dong Xu
- NeonatologyChildren's Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
| | - Mo Rezaiekhaligh
- NeonatologyChildren's Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
| | - Sherry Mabry
- NeonatologyChildren's Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
| | - Ricardo E Perez
- NeonatologyChildren's Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
| | - William E Truog
- NeonatologyChildren's Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
| | - Ikechukwu I Ekekezie
- NeonatologyChildren's Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
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Olmo MAN, Xu D, Rezaiekhaligh M, Mabry S, Perez RE, Truog WE, Ekekezie II. Podoplanin silencing disrupts membrane localization of phosphorylated ezrin/radixin/moesin proteins (ERM) and impairs capillary tube formation in lymphatic endothelial cells. FASEB J 2007. [DOI: 10.1096/fasebj.21.6.a1201-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Maria A Navarro Olmo
- NeonatologyChildren’s Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
| | - Dong Xu
- NeonatologyChildren’s Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
| | - Mo Rezaiekhaligh
- NeonatologyChildren’s Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
| | - Sherry Mabry
- NeonatologyChildren’s Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
| | - Ricardo E Perez
- NeonatologyChildren’s Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
| | - William E Truog
- NeonatologyChildren’s Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
| | - Ikechukwu I Ekekezie
- NeonatologyChildren’s Mercy Hospitals and Clinics/University of Missouri in Kansas City ‐ School of Medicine2401 Gillham Road, Pediatric Research Center, 4th FloorKansas CityMO64108
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Xu D, Guthrie JR, Mabry S, Sack TM, Truog WE. Mitochondrial aldehyde dehydrogenase attenuates hyperoxia-induced cell death through activation of ERK/MAPK and PI3K-Akt pathways in lung epithelial cells. Am J Physiol Lung Cell Mol Physiol 2006; 291:L966-75. [PMID: 16782756 DOI: 10.1152/ajplung.00045.2006] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Oxygen toxicity is one of the major risk factors in the development of the chronic lung disease or bronchopulmonary dysplasia in premature infants. Using proteomic analysis, we discovered that mitochondrial aldehyde dehydrogenase (mtALDH or ALDH2) was downregulated in neonatal rat lung after hyperoxic exposure. To study the role of mtALDH in hyperoxic lung injury, we overexpressed mtALDH in human lung epithelial cells (A549) and found that mtALDH significantly reduced hyperoxia-induced cell death. Compared with control cells (Neo-A549), the necrotic cell death in mtALDH-overexpressing cells (mtALDH-A549) decreased from 25.3 to 6.5%, 50.5 to 9.1%, and 52.4 to 15.1% after 24-, 48-, and 72-h hyperoxic exposure, respectively. The levels of intracellular and mitochondria-derived reactive oxygen species (ROS) in mtALDH-A549 cells after hyperoxic exposure were significantly lowered compared with Neo-A549 cells. mtALDH overexpression significantly stimulated extracellular signal-regulated kinase (ERK) phosphorylation under normoxic and hyperoxic conditions. Inhibition of ERK phosphorylation partially eliminated the protective effect of mtALDH in hyperoxia-induced cell death, suggesting ERK activation by mtALDH conferred cellular resistance to hyperoxia. mtALDH overexpression augmented Akt phosphorylation and maintained the total Akt level in mtALDH-A549 cells under normoxic and hyperoxic conditions. Inhibition of phosphatidylinositol 3-kinase (PI3K) activation by LY294002 in mtALDH-A549 cells significantly increased necrotic cell death after hyperoxic exposure, indicating that PI3K-Akt activation by mtALDH played an important role in cell survival after hyperoxia. Taken together, these data demonstrate that mtALDH overexpression attenuates hyperoxia-induced cell death in lung epithelial cells through reduction of ROS, activation of ERK/MAPK, and PI3K-Akt cell survival signaling pathways.
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Affiliation(s)
- Dong Xu
- Neonatology Research Laboratory, Children's Mercy Hospital, Pediatric Research Center, 4th Floor, 2401 Gillham Rd., Kansas City, MO 64108, USA.
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Sheffield M, Mabry S, Thibeault DW, Truog WE. Pulmonary nitric oxide synthases and nitrotyrosine: findings during lung development and in chronic lung disease of prematurity. Pediatrics 2006; 118:1056-64. [PMID: 16950998 DOI: 10.1542/peds.2006-0195] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Nitric oxide mediates and modulates pulmonary transition from fetal to postnatal life. NO is synthesized by 3 nitric oxide synthase isoforms. One key pathway of nitric oxide metabolism results in nitrotyrosine, a stable, measurable marker of nitric oxide production. OBJECTIVE The purpose of this study was to assess, by semiquantitative immunohistochemistry, nitric oxide synthase isoforms and nitrotyrosine at different airway and vascular tree levels in the lungs of neonates at different gestational ages and to compare results in control groups to those in infants with chronic lung disease. DESIGN/METHODS Formalin-fixed, paraffin-embedded, postmortem lung blocks were prepared for immunohistochemistry using antibodies to each nitric oxide synthase isoform and to nitrotyrosine. Blinded observers evaluated the airway and vascular trees for staining intensity (0-3 scale) at 5 levels and 3 levels, respectively. The control population consisted of infants from 22 to 42 weeks' gestation who died in < 48 hours. Results were compared with gestation-matched infants with varying severity of chronic lung disease. RESULTS In control and chronic lung disease groups, 22 to 42 weeks' gestation, staining for all 3 of the nitric oxide synthase isoforms was found in the airway epithelium from the bronchus to the alveolus or distal-most airspace. The abundance or distribution of nitric oxide synthase-3 staining in the airways did not show significant correlation with gestational age or severity of chronic lung disease. In the vascular tree, intense nitric oxide synthase-3 and moderate nitric oxide synthase-2 staining was found; nitric oxide synthase-1 was not consistently stained. Nitrotyrosine did stain in the pulmonary tree. Compared with controls where nitrotyrosine staining was minimal, regardless of gestation, in infants with chronic lung disease there was more than fourfold increase between severe chronic lung disease (n = 12) and either mild chronic lung disease or control infants (n = 16). CONCLUSIONS All 3 of the nitric oxide synthase isoforms and nitrotyrosine are detectable by immunohistochemistry early in lung development. Nitric oxide synthase ontogeny shows no significant changes in abundance or distribution with advancing gestational age nor with chronic lung disease. Nitrotyrosine is significantly increased in severe chronic lung disease.
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Affiliation(s)
- Mark Sheffield
- Children's Mercy Hospitals and Clinics, Section of Neonatology, Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri 64108, USA
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Ehlert CA, Truog WE, Thibeault DW, Garg U, Norberg M, Rezaiekhaligh M, Mabry S, Ekekezie II. Hyperoxia and tidal volume: Independent and combined effects on neonatal pulmonary inflammation. Neonatology 2006; 90:89-97. [PMID: 16534192 DOI: 10.1159/000092005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2005] [Accepted: 10/24/2005] [Indexed: 11/19/2022]
Abstract
BACKGROUND Hyperoxia and tidal volume mechanical ventilation are independent factors in the genesis of lung injury, but it remains unclear the extent to which each is responsible or contributes to this process in newborns. OBJECTIVES To study the independent and combined effects of hyperoxia and tidal volume mechanical ventilation on the induction of lung inflammation in a newborn piglet model of ventilator-induced lung injury. METHODS Following exposure to either ambient air or F(I)O2 = 1.0 for a period of 3 days, newborn piglets were randomized to receive mechanical ventilation with either high tidal volume (20 ml/kg) or low tidal volume (6 ml/kg) for 4 h while controlling for pH. RESULTS Monocyte chemoattractant protein-1 level in the lungs of animals randomized to hyperoxia with high tidal volume ventilation was significantly elevated, compared to all other groups (p < 0.05). Myeloperoxidase assayed in lung homogenate was found to be significantly higher in nonventilated animals exposed to hyperoxia (p < 0.01). Only in animals previously exposed to hyperoxia did the addition of high tidal volume ventilation further increase the level of myeloperoxidase present (p < 0.05). Pulmonary vascular resistance was significantly elevated after 4 h of mechanical ventilation compared to 1 h (p < 0.001). CONCLUSIONS We conclude that in neonatal piglets undergoing hyperoxic stress, superimposition of high tidal volume ventilation exacerbates the lung inflammation as assessed by lung monocyte chemoattractant protein-1 and level of myeloperoxidase.
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Affiliation(s)
- Carey A Ehlert
- Section of Neonatal-Perinatal Medicine, Department of Pediatrics, Children's Mercy Hospitals and Clinics, Kansas City, Mo., USA.
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Ekekezie II, Thibeault DW, Rezaiekhaligh MH, Norberg M, Mabry S, Zhang X, Truog WE. Endostatin and vascular endothelial cell growth factor (VEGF) in piglet lungs: effect of inhaled nitric oxide and hyperoxia. Pediatr Res 2003; 53:440-6. [PMID: 12595592 DOI: 10.1203/01.pdr.0000050121.70693.1a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Pulmonary hyperoxic injury manifests as widespread alveolar-epithelial and microvascular endothelial cell necrosis, resolution of which requires angiogenesis. We investigated the hypothesis that inhaled nitric oxide (iNO) and hyperoxia each decreases lung vascular endothelial growth factor (VEGF) expression but increases endostatin and that concurrent administration of both gases will show a greater effect. Piglets were randomized to breathe for 5 d room air (RA); RA + NO (RA + 50 ppm NO), O(2) (hyperoxia, F(I)O(2) >0.96), O(2) + NO, or O(2) + NO + REC (O(2) + NO plus recovery in 50% O(2) for 72 h. After the piglets were killed, we measured lung capillary leak, VEGF mRNA, VEGF, and endostatin protein in homogenates, plasma, and lavage. VEGF mRNA decreased significantly with O(2) and O(2) + NO compared with breathing RA (p < or = 0.05). VEGF protein declined in the experimental groups with a significant reduction in the recovery group compared with the RA group (p < or = 0.05). Similar but more dramatic, endostatin declined in all groups relative to the RA group (p < 0.001). Lavage fluid VEGF protein and lung capillary leak rose significantly with O(2) and O(2) + NO compared with RA, but endostatin was unchanged. At 72 h of recovery from hyperoxia, VEGF mRNA and lavage fluid VEGF but not lung VEGF protein had normalized. Hyperoxia and iNO suppresses lung endostatin expression, but iNO unlike hyperoxia alone does not alter lung VEGF production. Hyperoxia paradoxically raises lavageable VEGF levels. This latter effect and that on VEGF mRNA level but not protein is abrogated by recovery in reduced F(I)O(2) for 72 h.
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Affiliation(s)
- Ikechukwu I Ekekezie
- Department of Pediatrics, Section of Neonatology, Children's Mercy Hospitals and Clinics, University of Missouri, Kansas City School of Medicine, Kansas City, Missouri 64108-9883, USA.
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Kerns JW, Mabry S, Lopez R. Clinical inquiries. What is the best diagnostic approach to postmenopausal vaginal bleeding in women taking hormone replacement therapy? J Fam Pract 2001; 50:843-844. [PMID: 11674884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- J W Kerns
- Shenandoah Valley Family Practice Residency & Virginia Commonwealth University, Front Royal and Winchester, VA, USA
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Thibeault DW, Heimes B, Rezaiekhaligh M, Mabry S. Chronic modifications of lung and heart development in glucocorticoid-treated newborn rats exposed to hyperoxia or room air. Pediatr Pulmonol 1993; 16:81-8. [PMID: 8367221 DOI: 10.1002/ppul.1950160202] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We assessed the mechanics and morphology of the lung in 165 rats treated neonatally with either room air (RA), O2, RA + steroids, or O2 + steroids. Newborn Sprague-Dawley male rats were randomly assigned to these groups. O2-exposure (0.96-1.0 FiO2) lasted 5 days, and dexamethasone treatment consisted of eight daily S.C. injections of drug or buffer in successive doses of 0.5, 0.4, 0.3, 0.2, 0.1, 0.1, 0.1, and 0.1 mg/kg. At 58 days, right ventricular systolic pressure (RVP) was measured. At 60 days, all rats were sacrificed for obtaining lung weight and DNA, saline pressure-volume (P-V) curves, and morphometry. We weighted right ventricles (RV) and left ventricles + septa (LV). Hyperoxia alone did not, but steroid decreased survival rate to 79.4% (95.3% in RA rats, P < 0.02). Only 21 of 40 (52%) O2 + steroids rats survived, less than in both RA groups (P < 0.001). RV weight, RVP and muscularization of alveolar duct arteries were significantly increased in O2 vs. RA rats. In RA + steroids rats, weight of the LV was decreased but RV, RVP, and lung vasculature were not affected. These effects were additive in the O2 + steroid group. Wet lung weights and DNA were increased for RA + steroid rats over all others. O2 and steroids shifted the P-V curve to the left and O2 + steroids still further. Maximal lung volume increased significantly with RA + steroids and still further in O2 + steroids but not in O2 alone. O2 and steroids significantly increased the mean linear intercept and O2 + steroids even more so.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D W Thibeault
- University of Missouri-Kansas City School of Medicine, Mercy Hospital 64108-9898
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Thibeault DW, Rezaiekhaligh M, Mabry S. Lung antioxidant enzymes and cardiopulmonary responses in young rats exposed to hyperoxia and treated intratracheally with PEG catalase and superoxide dismutase. Exp Lung Res 1993; 19:137-51. [PMID: 8467759 DOI: 10.3109/01902149309031716] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The 27-day-old rat exposed to 100% oxygen (O2) for 8 days will have predictable lung vascular and parenchymal changes at 60 days of age. Using this model, the goals of this study are (1) to measure the lung antioxidant enzyme activities serially following intratracheal PEG antioxidant therapy during the 8-day O2 exposure; and (2) to assess chronic cardiopulmonary changes in the O2-exposed rats treated with PEG-CAT and/or PEG-CuZn SOD given intraperitoneally (IP) and/or intratracheally (IT). The study encompassed 202 male rats exposed to room air or oxygen. CuZn SOD doses were 300 U IT and 2000 U IP. The CAT dose was 500 or 4000 U IT and 10,000 U IP. At 60 days of age, the right ventricular systolic pressure (RVP), RV weight, % acinar wall arterial thickness, and parenchymal air space were significantly increased in O2-exposed rats compared to RA rats. The RVP, RV weight, and parenchymal changes were prevented by daily IT PEG-CAT 4000 U + CuZn SOD 300 U but the increased small artery muscularization was not. Three hours after the initial dose of IT PEG-CAT 4000 U, lung CAT activity was more than doubled and remained constant throughout the 8-day daily treatment course. This dose of CAT depressed the induction response to O2 of CuZn and MnSOD. It is concluded that daily intratracheal administration of PEG-CAT 4000 U + CuZn SOD 300 U can significantly ameliorate some of the chronic parenchymal and vascular lung O2 toxic changes. However, it appears that high-dose exogenous PEG-CAT suppresses the endogenous enzyme induction to hyperoxia of both CuZn and Mn-SOD.
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Affiliation(s)
- D W Thibeault
- University of Missouri-Kansas City School of Medicine, Children's Mercy Hospital 64108-9898
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Thibeault DW, Rezaiekhaligh M, Mabry S, Beringer T. Prevention of chronic pulmonary oxygen toxicity in young rats with liposome-encapsulated catalase administered intratracheally. Pediatr Pulmonol 1991; 11:318-27. [PMID: 1758756 DOI: 10.1002/ppul.1950110408] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The lungs and hearts of young rats exposed to 100% oxygen (O2) for 8 days (27 to 35 days of age) were studied following recovery in room air at 60 days of age using morphometric, biochemical, and physiological techniques. In an attempt to prevent chronic oxygen toxicity 153 rats had transtracheal catheters surgically implanted and were treated during the O2 exposure with daily intratracheal injections of liposome-encapsulated superoxide dismutase (SOD) and/or catalase (CAT). Oxygen exposure in this model results in chronic cardiopulmonary alterations which include pulmonary hypertension, right ventricular hypertrophy, and a decrease in number of pulmonary arterioles 25 to 50 microns in diameter with increased muscularization of their walls. The volume densities of the parenchyma, parenchymal air space, and the alveolar space are increased, while that of the combined alveolar ductal and respiratory bronchiolar space is decreased. Daily intratracheal administration of liposome-encapsulated CAT (160 U) during the O2 exposure prevented these chronic changes. Liposome-encapsulated SOD (110 U) or SOD (50 U) + CAT (70 U) did not appear to have a preventive effect. During the first 3 to 5 days following oxygen exposure the lung tissue enzymes SOD, CAT, and glutathione peroxidase markedly increased. We conclude that in the young rat animal model liposome-encapsulated CAT (160 U) given intratracheally during the period of O2 exposure is safe and will prevent the chronic vascular and parenchymal damage due to oxygen toxicity.
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Affiliation(s)
- D W Thibeault
- University of Missouri-Kansas City School of Medicine, School of Basic Life Sciences, Missouri
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Abstract
The aims of this study were to determine if neonatal hyperoxia exposure causes permanent lung damage and to define the relationship between neonatal lung oxygen toxicity and aging. Sprague-Dawley newborn rats (n = 85) breathed 100% oxygen (O2) or room air (RA) during the first 8 days of life, and then RA. At 2 and 22 months of age we assessed right ventricular (RV) systolic pressure (RVSP), RV weight, saline and air pressure-volume curves, volume density of lung parenchyma and nonparenchyma, parenchymal air space (PAS), mean linear intercept (Lm), number of small arteries/mm2 and the extent of their medial muscularization. Aging in RA did not affect the RVSP, RV weight, the number of small arteries/mm2, or their muscularization. The maximal lung volume/g of dry lung and the elastic recoil pressure between 40 and 90% maximal lung volume decreased. The volume density of lung parenchyma increased but the fraction of the lung parenchyma that was PAS decreased and that of the alveolar septa and Lm increased. The O2-treated rats at 60 days of age had increased RVSP and RV weights with a decrease in the small arteries/mm2. The lung parenchymal volume density and PAS increased and the density of alveolar septa decreased. The Lm increased and the alveoli/mm2 and elastic recoil pressure decreased. The lung damage seen in the O2-treated rats at 60 days persisted and in addition underwent the changes seen in the aging controls. However, the extent of muscularization of the arteries decreased. We conclude that neonatal hyperoxia causes permanent functional and structural changes of the lung but these do not interact with aging; that is, the effects of O2 toxicity and aging are additive but not synergistic.
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Affiliation(s)
- D W Thibeault
- University of Missouri-Kansas City School of Medicine, Children's Mercy Hospital
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