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Query: UMLS:C0242706 (
hyperoxia
)
5,219
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The hormetic effect, which extends the lifespan by various stressors, has been confirmed in Caenorhabditis elegans (C. elegans). We have previously reported that oxidative stress resistance in a long-lived mutant age-1 is associated with the hormesis. In the age-1 allele, which activates an insulin/
insulin-like growth factor
-1 (Ins/IGF-1) signaling pathway, the superoxide dismutase (SOD) and catalase activities increased during normal aging. We now demonstrate changes in the mitochondrial superoxide radical (*O(2)(-)) levels of the hormetic conditioned age-related strains. The *O(2)(-) levels in age-1 strain significantly decreased after intermittent
hyperoxia
exposure. On the other hand, this phenomenon was not observed in a daf-16 null mutant. This hormesis-dependent reduction of the *O(2)(-) levels was observed even if the mitochondrial Mn-SOD was experimentally reduced. Therefore, it is indicated that the hormesis is mediated by events that suppress the mitochondrial *O(2)(-) production. Moreover, some SOD gene expressions in the hormetic conditioned age-1 mutant were induced over steady state mRNA levels. These data suggest that oxidative stress-inducible hormesis is associated with a reduction of the mitochondrial *O(2)(-) production by activation of the antioxidant system via the Ins/IGF-1 signaling pathway.
...
PMID:Hyperoxia exposure induced hormesis decreases mitochondrial superoxide radical levels via Ins/IGF-1 signaling pathway in a long-lived age-1 mutant of Caenorhabditis elegans. 1828 59
Retinopathy of prematurity (ROP) is a vascular disease of the eye unique to preterm infants. The distinctive feature of ROP is that is an illness of the still-maturing organism. Thus, an understanding of the normal fetal development of the retina is fundamental to understanding the pathogenesis of ROP. Animal models of ROP differ in important attributes, a fact that is important for interpretation of results. However, all models have in common the finding that ROP is a biphasic disease. In the first phase, relative
hyperoxia
results in vaso-obliteration and vessel loss. The second phase is characterized by hypoxia-induced neovascularization resulting in retinal detachment and blindness. Oxygen-dependent vascular endothelial growth factor (VEGF) and oxygen-independent
insulin-like growth factor
(IGF-1) have been identified as important factors in the pathogenesis of ROP. These findings suggest new therapeutic approaches. Substitution of IGF-1 during the first phase of the disease may help prevent vessel loss, and administration of anti-angiogenic substances during the second phase may prevent pathological neovascularization.
...
PMID:[Pathogenesis of retinopathy of prematurity]. 1904 59
MicroRNAs (miRs) are small conserved RNA that regulate gene expression. Bioinformatic analysis of miRNA profiles during mouse lung development indicated a role for multiple miRNA, including miRNA-489. miR-489 increased on completion of alveolar septation [postnatal day 42 (P42)], associated with decreases in its conserved target genes
insulin-like growth factor
-1 (Igf1) and tenascin C (Tnc). We hypothesized that dysregulation of miR-489 and its target genes Igf1 and Tnc contribute to
hyperoxia
-induced abnormal lung development. C57BL/6 mice were exposed to normoxia (21%) or
hyperoxia
(85% O2) from P4 to P14, in combination with intranasal locked nucleic acid against miR-489 to inhibit miR-489, cytomegalovirus promoter (pCMV)-miR-489 to overexpress miR-489, or empty vector.
Hyperoxia
reduced miR-489 and increased Igf1 and Tnc. Locked nucleic acid against miR-489 improved lung development during
hyperoxia
and did not alter it during normoxia, whereas miR-489 overexpression inhibited lung development during normoxia. The 3' untranslated region in vitro reporter studies confirmed Igf1 and Tnc as targets of miR-489. While miR-489 was of epithelial origin and present in exosomes, its targets Igf1 and Tnc were produced by fibroblasts. Infants with bronchopulmonary dysplasia (BPD) had reduced lung miR-489 and increased Igf1 and Tnc compared with normal preterm or term infants. These results suggest increased miR-489 is an inhibitor of alveolar septation. During
hyperoxia
or BPD, reduced miR-489 and increased Igf1 and Tnc may be inadequate attempts at compensation. Further inhibition of miR-489 may permit alveolar septation to proceed. The use of specific miRNA antagonists or agonists may be a therapeutic strategy for inhibited alveolarization, such as in BPD.
...
PMID:Regulation of alveolar septation by microRNA-489. 2671 45
Rationale:
Antenatal factors, such as chorioamnionitis, preeclampsia, and postnatal injury, are associated with an increased risk for bronchopulmonary dysplasia (BPD) and pulmonary hypertension (PH) after preterm birth. IGF-1 (
insulin-like growth factor
-1) is markedly decreased in normal preterm infants, but whether IGF-1 treatment can prevent BPD or PH is unknown.
Objectives:
To evaluate whether postnatal treatment with rhIGF-1 (recombinant human IGF-1)/BP3 (binding peptide 3) improves lung growth and prevents PH in two antenatal models of BPD induced by intraamniotic exposure to endotoxin (ETX) or sFlt-1 (soluble fms-like tyrosine kinase 1), and in a postnatal model due to prolonged
hyperoxia
.
Methods:
ETX or sFlt-1 were administered into the amniotic sac of pregnant rats at Embryonic Day 20 to simulate antenatal models of chorioamnionitis and preeclampsia, respectively. Pups were delivered by cesarean section at Embryonic Day 22 and treated with rhIGF-1/BP3 (0.02-20 mg/kg/d intraperitoneal) or buffer for 2 weeks. Study endpoints included radial alveolar counts (RACs), vessel density, and right ventricular hypertrophy (RVH). Direct effects of rhIGF-1/BP3 (250 ng/ml) on fetal lung endothelial cell proliferation and tube formation and alveolar type 2 cell proliferation were studied by standard methods
in vitro
.
Measurements and Main Results:
Antenatal ETX and antenatal sFlt-1 reduced RAC and decreased RVH in infant rats. In both models, postnatal rhIGF-1/BP3 treatment restored RAC and RVH to normal values when compared with placebo injections. rhIGF-1/BP3 treatment also preserved lung structure and prevented RVH after postnatal
hyperoxia
.
In vitro
studies showed that rhIGF-1/BP3 treatment increased lung endothelial cell and alveolar type 2 cell proliferation.
Conclusions:
Postnatal rhIGF-1/BP3 treatment preserved lung structure and prevented RVH in antenatal and postnatal BPD models. rhIGF-1/BP3 treatment may provide a novel strategy for the prevention of BPD in preterm infants.
...
PMID:rhIGF-1/BP3 Preserves Lung Growth and Prevents Pulmonary Hypertension in Experimental Bronchopulmonary Dysplasia. 3210 32
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