Uteroplacental insufficiency decreases leptin expression and impairs lung development in growth-restricted newborn rats.

BACKGROUND: The study aimed to analyze the effect of uteroplacental insufficiency (UPI) on leptin expression and lung development of intrauterine growth restriction (IUGR) rats. METHODS: On day 17 of pregnancy, time-dated Sprague-Dawley rats were randomly divided into either an IUGR group or a control group. Uteroplacental insufficiency surgery (IUGR) and sham surgery (control) were conducted. Offspring rats were spontaneously delivered on day 22 of pregnancy. On postnatal days 0 and 7, rats' pups were selected at random from the control and IUGR groups. Blood was withdrawn from the heart to determine leptin levels. The right lung was obtained for leptin and leptin receptor levels, immunohistochemistry, proliferating cell nuclear antigen (PCNA), western blot, and metabolomic analyses. RESULTS: UPI-induced IUGR decreased leptin expression and impaired lung development, causing decreased surface area and volume in offspring. This results in lower body weight, decreased serum leptin levels, lung leptin and leptin receptor levels, alveolar space, PCNA, and increased alveolar wall volume fraction in IUGR offspring rats. The IUGR group found significant relationships between serum leptin, radial alveolar count, von Willebrand Factor, and metabolites. CONCLUSION: Leptin may contribute to UPI-induced lung development during the postnatal period, suggesting supplementation as a potential treatment. IMPACT: The neonatal rats with intrauterine growth restriction (IUGR) caused by uteroplacental insufficiency (UPI) showed decreased leptin expression and impaired lung development. UPI-induced IUGR significantly decreased surface area and volume in lung offspring. This is a novel study that investigates leptin expression and lung development in neonatal rats with IUGR caused by UPI. If our findings translate to IUGR infants, leptin may contribute to UPI-induced lung development during the postnatal period, suggesting supplementation as a potential treatment.

Inhibition of FABP4 attenuates hyperoxia-induced lung injury and fibrosis via inhibiting TGF-ß signaling in neonatal rats.

Bronchopulmonary dysplasia (BPD) is a chronic lung disease characterized by interrupted alveologenesis and alveolar simplification caused by oxygen therapy in premature infants. Metabolic dysfunction is involved in the pathogenesis of BPD. Fatty acid-binding protein 4 (FABP4) is significantly increased in specific lung tissues in patients with BPD. Therefore, we investigated whether BMS309403, an FABP4 inhibitor that can mitigate tissue fibrosis, can regulate pulmonary fibrotic processes in newborn rats exposed to hyperoxia. Newborn rat pups were exposed to room air (RA; 21% O2 ) or 85% O2 from 5 to 14 days of age and were then allowed to recover in RA until 29 days of age. They received intraperitoneal injection with placebo (phosphate-buffered saline [PBS]) or BMS 309403 (0.5 mg or 1.0 mg kg-1 d-1 ) every other day from 4 to 14 days of age then were divided into O2 plus PBS or low dose or high dose and RA plus PBS or low dose or high dose groups. We assessed lung histology and evaluated lung collagen I, FABP4 as well as TGF-ß1 expression at 14 and 29 days of age. In the hyperoxia injury-recovery model, prophylactic BMS309403 treatment reduced mean linear intercept values and FABP4 expression (p < 0.001). Prophylactic BMS309403 treatment mitigated pulmonary fibrosis and TGF-ß1 expression immediately after hyperoxia exposure (p < 0.05). The attenuation of hyperoxia-induced alveolar developmental impairment and pulmonary fibrosis by FABP4 inhibition indicated that such inhibition has potential clinical and therapeutic applications.

Kidney Injuries and Evolution of Chronic Kidney Diseases Due to Neonatal Hyperoxia Exposure Based on Animal Studies.

Preterm birth interrupts the development and maturation of the kidneys during the critical growth period. The kidneys can also exhibit structural defects and functional impairment due to hyperoxia, as demonstrated by various animal studies. Furthermore, hyperoxia during nephrogenesis impairs renal tubular development and induces glomerular and tubular injuries, which manifest as renal corpuscle enlargement, renal tubular necrosis, interstitial inflammation, and kidney fibrosis. Preterm birth along with hyperoxia exposure induces a pathological predisposition to chronic kidney disease. Hyperoxia-induced kidney injuries are influenced by several molecular factors, including hypoxia-inducible factor-1α and interleukin-6/Smad2/transforming growth factor-ß, and Wnt/ß-catenin signaling pathways; these are key to cell proliferation, tissue inflammation, and cell membrane repair. Hyperoxia-induced oxidative stress is characterized by the attenuation or the induction of multiple molecular factors associated with kidney damage. This review focuses on the molecular pathways involved in the pathogenesis of hyperoxia-induced kidney injuries to establish a framework for potential interventions.

Cervical Noninvasive Vagus Nerve Stimulation for Migraine and Cluster Headache: A Systematic Review and Meta-Analysis.

BACKGROUND: Noninvasive vagus nerve stimulation (nVNS) has been proposed as a new neuromodulation therapy to treat primary headache disorders. The purpose of this study was to analyze the effectiveness and safety of peripheral nerve stimulation of the cervical branch of the vagal nerve for primary headache disorders. METHODS: A systematic review and meta-analysis of the literature was carried out on randomized controlled trials of nVNS for treating headaches. We searched the Medline, Embase, and CENTRAL databases until January 29, 2019. A random-effects model was used to report all outcomes. The primary outcomes were a reduction in headache days or attacks and pain-free status within 30 min. Secondary outcomes were: the pain-relief status within 30 min, the pain-relief status at 60 min, abortive medication use, ≥50% responder rate, pain-free status in ≥50% of treated attacks, adverse events, and satisfaction. RESULTS: In total, 983 patients were included from six trials. We found that nVNS was effective in achieving a pain-free status within 30 min (odds ratio [OR], 2.27; 95% confidence interval [CI], 1.16~4.44; p = 0.02), pain-relief status within 30 min (OR, 1.8; 95% CI, 1.17~2.78; p = 0.007), pain-relief status at 60 min (OR, 1.93; 95% CI, 1.2~3.1; p = 0.006), a reduction in abortive medication use (OR, 0.61; 95% CI, 0.41~0.92; p = 0.02), and pain-free status in ≥50% of treated attacks (OR, 2.15; 95% CI, 1.27~3.66; p = 0.005) compared to sham-device treatment. There were no significant differences in decreased headache days (standardized mean difference (SMD), -0.159; 95% CI, -0.357~0.04; p = 0.117), adverse events (OR, 1.084; 95% CI, 0.559~2.104; p = 0.811), or satisfaction (OR, 1.45; 95% CI, 0.97~2.17; p = 0.07) between nVNS and sham-device treatment. The ≥50% responder rate could not be determined (OR, 3.34; 95% CI, 0.83~13.33; p = 0.09; I 2 = 73%). CONCLUSIONS: Cervical nVNS is effective for acute pain relief for migraine and cluster headache. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration number CRD42019126009.

Bubble CPAP Support after Discontinuation of Mechanical Ventilation Protects Rat Lungs with Ventilator-Induced Lung Injury.

BACKGROUND: Bubble continuous positive airway pressure (BCPAP) has been used in neonates with respiratory distress for decades, but its lung-protective effect and underlying mechanism has not been investigated. OBJECTIVES: To test the hypothesis that BCPAP use after extubation decreases lung injury and that alterations to lung nitric oxide synthase (NOS) 3 expression may be one of the underlying mechanisms. METHODS: We compared gas exchange, lung injury severity, and lung NOS expression among rats with ventilator-induced lung injury (VILI) treated with either BCPAP or spontaneous breathing. After high tidal volume ventilation for 30 min, the rats were randomly divided to three groups: a control group underwent spontaneous breathing (n = 7), and two BCPAP groups were treated with the bubble technique with either a 2.5-mm-diameter (n = 7) or a 5.5-mm-diameter (n = 7) expiratory limb for 2 h. RESULTS: The bubble technique (2.5 and 5.5 mm diameter combined) resulted in a significantly higher PaO2, decreased alveolar protein levels (1.01 vs. 1.43 mg/kg, p < 0.05), a lower lung injury score (3.87 vs. 4.86, p < 0.05), and decreased NOS3 expression (1.99 vs. 3.32, p < 0.05) compared to spontaneous breathing in the control group. BCPAP with a 2.5-mm-diameter and with a 5.5-mm-diameter expiratory limb was not different with regard to gas exchange, alveolar protein levels, and lung injury scores, but there was a trend for lower NOS3 expression in the 5.5-mm group (1.41 vs. 2.56, p = 0.052). CONCLUSIONS: BCPAP decreases lung injury in rats with VILI after stopping mechanical ventilation. Attenuation of lung NOS3 expression may be one of the underlying mechanisms.

Maternal nicotine exposure during gestation and lactation induces kidney injury and fibrosis in rat offspring.

BACKGROUND: Maternal tobacco smoke exposure adversely affected fetal kidney development. Nicotine stimulates epithelial-mesenchymal transition and connective tissue growth factor (CTGF) expression in the renal epithelium. We hypothesized that maternal nicotine exposure would induce kidney fibrosis and involve CTGF in newborn rats. METHODS: Nicotine was administered to pregnant Sprague-Dawley rats at a dose of 6 mg/kg/d from gestational days 7-21 and gestational day 7 to postnatal day 14. A control group was injected with normal saline. Neonatal kidney tissues underwent histological analysis, collagen measurement, and western blot analysis. RESULTS: Tubular injury scores and total collagen contents were significantly higher in rats born to nicotine-treated dams than in rats born to normal saline-treated dams on postnatal days 7 and 21. Masson's trichrome staining further verified the presence of kidney fibrosis. Prenatal and/or postnatal nicotine exposure increased CTGF expression on postnatal days 7 and 21. CONCLUSION: Maternal nicotine exposure during gestation and lactation induces neonatal kidney fibrosis, and CTGF may be involved in the pathogenesis of kidney fibrosis. These results may be relevant to premature low-birth-weight infants who are conveyed a high risk of developing chronic kidney disease and exposed to breast milk of smoking mothers during the neonatal period.

Combined effects of maternal inflammation and neonatal hyperoxia on lung fibrosis and RAGE expression in newborn rats.

BACKGROUND: Receptors for advanced glycation end products (RAGE) have been implicated in fibrotic processes. We hypothesized that lung fibrosis induced by maternal lipopolysaccharide (LPS)-mediated inflammation and neonatal hyperoxia involves RAGE in newborn rats. METHODS: Pregnant Sprague-Dawley rats received intraperitoneal injections of LPS or normal saline (NS) on 20 and 21 d of gestation. The pups were reared in room air (RA) or an O2-enrich atmosphere (O2), creating the four study groups, NS + RA, NS + O2, LPS + RA, and LPS + O2. The O2 treatment was >95% O2 for 7 d, followed by 60% O2 for 14 d. RESULTS: Rat pups born to LPS-injected dams exhibited significantly higher lung interferon-γ and interleukin-1ß (IL-1ß) on postnatal day 7 than the pups born to NS-injected dams. Rat pups reared in hyperoxia expressed higher lung IL-10 on postnatal day 7, compared with the RA-reared pups. The LPS + O2 group had significantly higher total collagen and transforming growth factor-ß1 on postnatal days 7 and 21 than the NS+RA group. RAGE mRNA and sRAGE protein expression were significantly lower in the LPS + O2 group on postnatal day 7 than the NS+RA group. CONCLUSION: RAGE may be involved in the pathogenesis of lung fibrosis induced by maternal systemic inflammation and postnatal hyperoxia in rat neonates.

Altered purine and pentose phosphate pathway metabolism in uteroplacental insufficiency-induced intrauterine growth restriction offspring rats impair intestinal function.

This study aimed to identify metabolic alterations in the small intestine of newborn rats with intrauterine growth restriction (IUGR), a condition linked to intestinal dysfunction. Pregnant Sprague Dawley rats underwent bilateral uterine artery ligation on gestational day 17 to induce intrauterine growth restriction or sham surgery. Rat pups were delivered spontaneously on gestational day 22. Small intestine tissues were collected on postnatal days 0 and 7 from offspring. Liquid chromatography-mass spectrometry analysis was performed to investigate untargeted metabolomic profiles. Western blot analysis assessed protein expression of key regulators. Newborn rats with intrauterine growth restriction exhibited distinct small intestine metabolic profiles compared to controls on postnatal day 0. Notably, significant alterations were observed in purine metabolism, the pentose phosphate pathway, and related pathways. Western blot analysis revealed a decrease expression in transketolase, a key enzyme of the pentose phosphate pathway, suggesting impaired activity of the pentose phosphate pathway. Additionally, decreased expression of tight junction proteins ZO-1 and occludin indicated compromised intestinal barrier function in rats with intrauterine growth restriction. Similar metabolic disruptions persisted on postnatal day 7, with further reductions in tricarboxylic acid cycle intermediates and folate biosynthesis precursors. Interestingly, lysyl-glycine, a protein synthesis marker, was elevated in rats with intrauterine growth restriction. Our findings reveal a distinct metabolic signature in the small intestine of neonatal rats with intrauterine growth restriction, characterized by disruptions in the pentose phosphate pathway, purine metabolism, and energy production pathways. These novel insights suggest potential mechanisms underlying IUGR-associated intestinal dysfunction and impaired growth.

Circulating MicroRNAs as a biomarker signature of perinatal asphyxia.

AIM: This study aimed to explore whether microRNAs (miRNAs) could serve as biomarkers of perinatal asphyxia and whether they were correlated with severity of brain magnetic resonance imaging. METHODS: We prospectively enrolled 26 full-term newborns, including 10 with perinatal asphyxia and 16 healthy controls. Plasma samples were collected at 0-6 h and 7 days of age. Encephalopathy was classified according to modified Sarnat staging. Magnetic resonance imaging was performed in surviving infants within 30 days of birth, and a score was established. We used next-generation sequencing to explore differentially expressed miRNAs, which were then further validated using quantitative reverse transcription real-time polymerase chain reaction (RT-PCR). RESULTS: A significantly lower expression of miR-486-5p was found at 0-6 h of age in the asphyxiated newborns compared with the healthy controls (p = 0.005). The area under the receiver operating characteristic curve (AUC) of miR-486-5p at 0-6 h of age to differentiate the perinatal asphyxia group from the healthy control group was 0.831, and the AUC to differentiate newborns eligible for therapeutic hypothermia from others was 0.782. In addition, a lower expression of miR-486-5p at 7 days of age was noted in the asphyxiated newborns with adverse outcomes compared to those with normal outcomes. CONCLUSION: MiR-486-5p may be a biomarker of perinatal asphyxia in newborns, and further research is warranted to clarify its role.

Rho-kinase inhibitor Y-27632 attenuates pulmonary hypertension in hyperoxia-exposed newborn rats.

AIM: To test the hypothesis that neonatal hyperoxia induced pulmonary hypertension accompanied by increased Rho-kinase expression in rat lungs and that Rho-kinase inhibitor could attenuate right ventricular hypertrophy and pulmonary arterial remodeling. METHODS: Newborn rats were exposed to >95% O2 in the first week after birth, then to 60% O2 in the following 2 weeks. Control pups were exposed to room air over the same periods. The pups were injected with either Rho-kinase inhibitor Y-27632 (10 mg·kg(-1)·d(-1), ip) or vehicle from postnatal d 14 to 20. Lung and heart tissues were collected on postnatal d 7 and 21. Rho-kinase activity in lungs was measured using Western blotting and immunohistochemistry. The right ventricular hypertrophy and arterial medial wall thickness (MWT) were assessed morphologically. RESULTS: Rho-kinase activity in lungs was comparable between the hyperoxic and control pups on postnatal d 7, but it had a more than 2-fold increase in the hyperoxic pups on postnatal d 21. Moreover, the hyperoxic exposure induced structural features of pulmonary hypertension, as shown by the right ventricular hypertrophy and significantly increased arterial MWT. Administration with Y-27632 effectively blocked the hyperoxia-induced increase of Rho-kinase activity in lungs, and attenuated the right ventricular hypertrophy. CONCLUSION: Rho-kinase inhibitor may be a novel therapy for attenuating the hyperoxia-induced structural changes in pulmonary hypertension.

Tissue plasminogen activator attenuates ventilator-induced lung injury in rats.

AIM: To test the hypothesis that the tissue plasminogen activator (tPA) may counteract the inhibitory effect of plasminogen activator inhibitors (PAI) and attenuate lung injury in a rat model of ventilator-induced lung injury (VILI). METHODS: Adult male Sprague-Dawley rats were ventilated with a HVZP (high-volume zero PEEP) protocol for 2 h at a tidal volume of 30 mL/kg, a respiratory rate of 25 breaths/min, and an inspired oxygen fraction of 21%. The rats were divided into 3 groups (n=7 for each): HVZP+tPA group receiving tPA (1.25 mg/kg, iv) 15 min before ventilation, HVZP group receiving HVZP+vehicle injection, and a control group receiving no ventilation. After 2 h of ventilation, the rats were killed; blood and lungs were collected for biochemical and histological analyses. RESULTS: HVZP ventilation significantly increased total protein content and the concentration of macrophage inflammatory protein-2 (MIP-2) in the bronchoalveolar lavage fluid (BALF) as well as the lung injury score. Rats that received HVZP ventilation had significantly higher lung PAI-1 mRNA expression, plasma PAI-1 and plasma D-dimer levels than the control animals. tPA treatment significantly reduced the BALF total protein and the lung injury score as compared to the HVZP group. tPA treatment also significantly decreased the plasma D-dimer levels and the HVZP ventilation-induced lung vascular fibrin thrombi. tPA treatment showed no effect on MIP-2 level in BALF. CONCLUSION: These results demonstrate that VILI increases lung PAI-1 mRNA expression, plasma levels of PAI-1 and D-dimers, lung injury score and vascular fibrin deposition. tPA can attenuate VILI by decreasing capillary-alveolar protein leakage as well as local and systemic coagulation as shown by decreased lung vascular fibrin deposition and plasma D-dimers.

Molecular mechanisms underlying hyperoxia-induced lung fibrosis.

Supplemental oxygen is often used to treat newborns with respiratory disorders. Exposure to high concentration of oxygen and long-term oxygen causes inflammation and acute lung injury. The acute inflammatory phase is followed by a fibroproliferative repair phase, leading to lung fibrosis. Many infants with lung fibrosis develop significant respiratory morbidities including reactive airways dysfunction and obstructive lung disease during childhood. Despite the absence of effective treatments and the incomplete understanding regarding mechanisms underlying fibrosis, extensive literature regarding lung fibrosis from in vitro and in vivo hyperoxia-exposed models is available. In this review, we discuss molecular mediators and signaling pathways responsible for increased fibroblast proliferation and collagen production, excessive extracellular matrix accumulation, and eventually, lung fibrosis. We discuss each of these mediators separately to facilitate clear understanding as well as significant interactions occurring among these molecular mediators and signaling pathways.

Roxadustat attenuates hyperoxia-induced lung injury by upregulating proangiogenic factors in newborn mice.

BACKGROUND: Premature infants who require oxygen therapy for respiratory distress syndrome often develop bronchopulmonary dysplasia, a chronic lung disease characterized by interrupted alveologenesis. Disrupted angiogenesis inhibits alveologenesis; however, the mechanisms through which disrupted angiogenesis affects lung development are poorly understood. Hypoxia-inducible factors (HIFs) are transcription factors that activate multiple oxygen-sensitive genes, including those encoding for vascular endothelial growth factor (VEGF). However, the HIF modulation of angiogenesis in hyperoxia-induced lung injury is not fully understood. Therefore, we explored the effects of roxadustat, an HIF stabilizer that has been shown to promote angiogenesis, in regulating pulmonary angiogenesis on hyperoxia exposure. METHODS: C57BL6 mice pups reared in room air and 85% O2 were injected with phosphate-buffered saline or 5 mg/kg or 10 mg/kg roxadustat. Their daily body weight and survival rate were recorded. Their lungs were excised for histology and angiogenic factor expression analyses on postnatal Day 7. RESULTS: Exposure to neonatal hyperoxia reduced body weight; survival rate; and expressions of von Willebrand factor, HIF-1α, phosphor mammalian target of rapamycin, VEGF, and endothelial nitric oxide synthase and increased the mean linear intercept values in the pups. Roxadustat administration reversed these effects. CONCLUSION: Hyperoxia suppressed pulmonary vascular development and the expression of proangiogenic factors. Roxadustat promoted pulmonary angiogenesis on hyperoxia exposure by stabilizing HIF-1α and upregulating the expression of proangiogenic factors, indicating its potential in clinical and therapeutic applications.

TRIM72 mediates lung epithelial cell death upon hyperoxia exposure.

BACKGROUND: Premature infants often require oxygen (O2) therapy for respiratory distress syndrome; however, excessive use of O2 can cause clinical conditions such as bronchopulmonary dysplasia. Although many treatment methods are currently available, they are not effective in preventing bronchopulmonary dysplasia. Herein, we explored the role of tripartite motif protein 72 (TRIM72), a factor involved in repairing alveolar epithelial wounds, in regulating alveolar cells upon hyperoxia exposure. METHODS: In this in vivo study, we used Sprague-Dawley rat pups that were reared in room air or 85% O2 for 2 weeks after birth. The lungs were excised for histological analyses, and TRIM72 expression was assessed on postnatal days 7 and 14. For in vitro experiments, RLE-6TN cells (i.e., rat alveolar type II epithelial cells) and A549 cells (i.e., human lung carcinoma epithelial cells) were exposed to 85% O2 for 5 days. The cells were then analyzed for cell viability, and TRIM72 expression was determined. RESULTS: Exposure to hyperoxia reduced body and lung weight, increased mean linear intercept values, and upregulated TRIM72 expression. In vitro study results revealed increased or decreased lung cell viability upon hyperoxia exposure depending on the suppression or overexpression of TRIM72, respectively. CONCLUSION: Hyperoxia upregulates TRIM72 expression in neonatal rat lung tissue; moreover, it initiates TRIM72-dependent alveolar epithelial cell death, leading to hyperoxia-induced lung injury.

Acute Appearance of a Neck Mass in an 11-Year-Old Girl.

Pustular abscess formation in the parotid gland is a rare complication following mumps virus infection. This is the second case report of pediatric parotid pustular abscess accompanied with mumps virus infection. Continuous antibiotics prescription without surgery is an eligible treatment for this patient.

High amplitude bubble continuous positive airway pressure decreases lung injury in rats with ventilator-induced lung injury.

BACKGROUND: Bubble continuous positive airway pressure (BCPAP) has been used in neonates with respiratory distress for decades; however, the optimal setting for BCPAP circuits remains unknown. This study compared the gas exchange efficiency and lung protection efficacy between conventional and high-amplitude BCPAP devices. METHODS: We compared gas exchange, lung volume, and pulmonary inflammation severity among rats with ventilator-induced lung injury (VILI) that were treated with conventional BCPAP (BCPAP with an expiratory limb at 0°), high-amplitude BCPAP (BCPAP with an expiratory limb at 135°), or spontaneous breathing (SB). After mechanical ventilation for 90 minutes, the rats were randomly divided into four groups: a control group (euthanized immediately; n = 3), an SB group (n = 8), and two BCPAP groups that received BCPAP with the expiratory limb at either 0° (n = 8) or 135° (n = 7) for 90 minutes. RESULTS: The high-amplitude BCPAP group exhibited significantly lower alveolar protein, lung volume, and Interleukin-6 (IL-6) levels than did the SB group. The high-amplitude BCPAP group exhibited significantly lower IL-6 levels than did the conventional BCPAP group. The two BCPAP groups demonstrated no difference in gas exchange efficiency. CONCLUSION: High-amplitude BCPAP reduced lung inflammation and alveolar overdistension in rats with VILI after mechanical ventilation was ceased. Thus high-amplitude BCPAP may offer a superior lung protective effect than conventional BCPAP.

Human mesenchymal stem cells ameliorate experimental pulmonary hypertension induced by maternal inflammation and neonatal hyperoxia in rats.

Pulmonary hypertension is a critical problem in infants with bronchopulmonary dysplasia. This study determined the therapeutic effects of human mesenchymal stem cells (MSCs) on pulmonary hypertension in an animal model. Pregnant Sprague-Dawley rats were intraperitoneally injected with lipopolysaccharide (LPS, 0.5 mg/kg/day) on gestational days 20 and 21. The pups were randomly assigned to two treatment conditions: room air (RA) or an O2-enriched atmosphere. On postnatal day 5, they were intratracheally transplanted with human MSCs (3 × 105 and 1 × 106 cells) in 0.03 mL of normal saline (NS). Five study groups were examined: normal, LPS+RA+NS, LPS+O2+NS, LPS+O2+MSCs (3 × 105 cells), and LPS+O2+MSCs (1 × 106 cells). On postnatal day 14, the pup lungs and hearts were collected for histological examinations. The LPS+RA+NS and LPS+O2+NS groups exhibited a significantly higher right ventricle (RV):left ventricle (LV) thickness ratio and medial wall thickness (MWT) and higher ß-myosin heavy chain (ß-MHC) and toll-like receptor (TLR) 4 expression than did the normal group. Human MSC transplantation in LPS- and O2-treated rats reduced the MWT, RV:LV thickness ratio, and ß-MHC and TLR4 expression to normal levels. Thus, intratracheal human MSC transplantation ameliorates pulmonary hypertension, probably by suppressing TLR4 expression in newborn rats.

Uteroplacental Insufficiency Alters the Retinoid Pathway and Lung Development in Newborn Rats.

BACKGROUND: Intrauterine growth retardation (IUGR) is associated with reduced lung function during infancy and perhaps throughout adulthood. The retinoic acid (RA) signaling pathway modulates pre- and postnatal lung development. This study was conducted to test our hypothesis that uteroplacental insufficiency alters the elements of the retinoid pathway in developing lungs. METHODS: On Gestation Day 18, either uteroplacental insufficiency was induced through bilateral uterine vessel ligation (IUGR group) or sham surgery (control group) was performed. Lung tissues from the offspring were examined through Western blotting, immunohistochemistry, and morphometry on Postnatal Day 3 and Postnatal Day 7. RESULTS: Compared with control rats, the IUGR rats exhibited significantly lower body weights on Postnatal Day 3 and Postnatal Day 7 and significantly lower lung weights on Postnatal Day 3. Uteroplacental insufficiency significantly increased RA receptor (RAR)-ß protein expression on Postnatal Day 3. The expression of RAR-α, RAR-γ, cellular RA-binding protein-1, and cellular RA-binding protein-2 between the control and IUGR rats was comparable on Postnatal Day 3 and Postnatal Day 7. Compared with the control rats, the IUGR rats exhibited a significantly higher volume fraction of alveolar airspace on Postnatal Day 3 and Postnatal Day 7 and a significantly lower volume fraction of alveolar walls on Postnatal Day 3. CONCLUSION: Uteroplacental insufficiency causes defective alveolarization and transient increases in RAR-ß expression in the lungs of newborn rats. The retinoid pathway may be one of the probable pathways mediating lung abnormalities caused by uteroplacental insufficiency.

Klf10 deficiency in mice exacerbates pulmonary inflammation by increasing expression of the proinflammatory molecule NPRA.

KLF10 is a transforming growth factor (TGF)-ß/Smad downstream regulated gene. KLF10 binds to the promoter of target genes and mimics the effects of TGF-ß as a transcriptional factor. In our laboratory, we noted that Klf10 deficiency in mice is associated with significant inflammation of the lungs. However, the precise mechanism of this association remains unknown. We previously identified NPRA as a target gene potentially regulated by KLF10 through direct binding; NPRA knockout have known that prevented lung inflammation in a mouse model of allergic asthma. Here, we further explored the regulatory association between KLF10 and NPRA on the basis of the aforementioned findings. Our results demonstrated that KLF10 acts as a transcriptional repressor of NPRA and that KLF10 binding reduces NPRA expression in vitro. Compared with wild-type mice, Klf10-deficient mice were more sensitive to lipopolysaccharide or ovalbumin challenge and showed more severe inflammatory histological changes in the lungs. Moreover, Klf10-deficient mice showed pulmonary neutrophil accumulation. These findings collectively reveal the precise site where KLF10 signaling affects pulmonary inflammation by attenuating NPRA expression. They also verify the importance of KLF10 and atrial natriuretic peptide/NPRA in exerting influences on chronic pulmonary disease pathogenesis.