ET-1 mediates the release of reactive oxygen species and TNF-α in lung tissue by protein kinase C α and β1

Effects of pulmonary surfactant combined with noninvasive positive pressure ventilation in neonates with respiratory distress syndrome

BACKGROUND

Neonatal respiratory distress syndrome (NRDS) is one of the most common diseases in neonatal intensive care units, with an incidence rate of about 7% among infants. Additionally, it is a leading cause of neonatal death in hospitals in China. The main mechanism of the disease is hypoxemia and hypercapnia caused by lack of surfactant.

AIM

To explore the effect of pulmonary surfactant (PS) combined with noninvasive positive pressure ventilation on keratin-14 (KRT-14) and endothelin-1 (ET-1) levels in peripheral blood and the effectiveness in treating NRDS.

METHODS

Altogether 137 neonates with respiratory distress syndrome treated in our hospital from April 2019 to July 2021 were included. Of these, 64 control cases were treated with noninvasive positive pressure ventilation and 73 observation cases were treated with PS combined with noninvasive positive pressure ventilation. The expression of KRT-14 and ET-1 in the two groups was compared. The deaths, complications, and PaO2, PaCO2, and PaO2/FiO2 blood gas indexes in the two groups were compared. Receiver operating characteristic curve (ROC) analysis was used to determine the diagnostic value of KRT-14 and ET-1 in the treatment of NRDS.

RESULTS

The observation group had a significantly higher effectiveness rate than the control group. There was no significant difference between the two groups in terms of neonatal mortality and adverse reactions, such as bronchial dysplasia, cyanosis, and shortness of breath. After treatment, the levels of PaO2 and PaO2/FiO2 in both groups were significantly higher than before treatment, while the level of PaCO2 was significantly lower. After treatment, the observation group had significantly higher levels of PaO2 and PaO2/FiO2 than the control group, while PaCO2 was notably lower in the observation group. After treatment, the KRT-14 and ET-1 levels in both groups were significantly decreased compared with the pre-treatment levels. The observation group had a reduction of KRT-14 and ET-1 levels than the control group. ROC curve analysis showed that the area under the curve (AUC) of KRT-14 was 0.791, and the AUC of ET-1 was 0.816.

CONCLUSION

Combining PS with noninvasive positive pressure ventilation significantly improved the effectiveness of NRDS therapy. KRT-14 and ET-1 levels may have potential as therapeutic and diagnostic indicators.

Impact of atorvastatin on plasma and cardiac biomarkers of inflammation, oxidative stress, and fibrosis in a rat model of streptozotocin-induced diabetes

Oxidative stress and fibrosis foster the development of cardiovascular disease (CVD) in diabetes. Atorvastatin protects against cardiovascular diseases in diabetes patients. However, the mechanisms are not completely known. This study evaluated the impact of atorvastatin on vascular and myocardial oxidative stress, inflammation, and fibrosis in a model of diabetes. Male Wistar rats were assigned into four groups; control rats, atorvastatin-treated rats (Ator, 40 mg/kg given by oral gavage for 6 weeks), diabetes rats (DM, single IP 40 mg/kg streptozotocin), and diabetes rats treated with atorvastatin (DM + Ator). Serum and cardiac inflammatory, oxidant, and fibrotic markers were measured. Cardiac fibrosis was evaluated by Masson trichrome stain. Streptozotocin-induced diabetes as documented by the marked elevation in blood glucose. Levels of oxidant biomarkers of serum and cardiac nitrite, cardiac nitrate, and cardiac thiobarbituric acid reactive substances (TBARS) were increased in the DM group. The use of atorvastatin reduced nitrite and TBARS levels. Serum and cardiac inflammatory factors of endothelin-1 (ET-1) were elevated in the DM group, and the use of atorvastatin reduced these increases. Cardiac C-reactive protein tended to increase in the DM group and the use of atorvastatin reduced its level. Cardiac interstitial fibrosis was increased in the DM group with a parallel increase in the platelet-derived growth factor level. The use of atorvastatin reduced cardiac fibrosis. Diabetes was associated with an increase in serum and/or myocardial markers of oxidative stress, inflammation, and fibrosis. The use of atorvastatin reduced cardiac interstitial fibrosis and decreased cardiac oxidant and inflammatory biomarkers.

Inhibitory effects of Syzygium jambos extract on biomarkers of endothelial cell activation

Background

Disordered endothelial cell activation plays an important role in the pathophysiology of atherosclerosis, cancer, sepsis, viral infections, and inflammatory responses. There is interest in developing novel therapeutics to regulate endothelial cell function in atherothrombotic, metabolic, vascular, and hematological diseases. Extracts from leaves of the Syzygium jambos (L.) Alston (S. jambos) trees have been proposed to treat cardiovascular diseases and diabetes through unclear mechanisms. We investigated the effects of the S. jambos extract on biomarkers of endothelial dysfunction and immune responses in the human endothelial cell line, EA.hy926.

Methods

Leaves of S. jambos were collected, concocted and lyophilized. To study the effects of S. jambos on endothelial cell activation, we used the human endothelial cell line. IL-6 levels were measured using qPCR and ELISA. PDI activity was measured using Insulin Turbidity and Di-E-GSSG assays. CM-H2DCFDA was used to study ROS levels. Migration assay was used to study S. jambos effect on ex vivo human polymorphonuclear and human mononuclear cells.

Results

Our results show that incubation of EA.hy926 cells with ET-1 led to a 6.5 ± 1.6 fold increase in IL-6 expression by qPCR, an event that was blocked by S. jambos. Also, we observed that ET-1 increased extracellular protein disulfide isomerase (PDI) activity that was likewise dose-dependently blocked by S. jambos (IC₅₀ = 14 μg/mL). Consistent with these observations, ET-1 stimulated ex vivo human polymorphonuclear and mononuclear cell migration that also was dose-dependently blocked by S. jambos. In addition, ET-1 stimulation led to significant increases in ROS production that were sensitive to S. jambos.

Conclusion

Our results suggest that the S. jambos extract represents a novel cardiovascular protective pharmacological approach to regulate endothelial cell activation, IL-6 expression, and immune-cell responses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03572-7.

Effects of Pulmonary Surfactant Combined with Noninvasive Positive Pressure Ventilation on KRT-14 and ET-1 Levels in Peripheral Blood and Therapeutic Effects in Neonates with Respiratory Distress Syndrome

This study is aimed at exploring the effect of pulmonary surfactant (PS) combined with noninvasive positive pressure ventilation on the levels of Keratin-14 (KRT-14) and Endothelin-1 (ET-1) in peripheral blood and the therapeutic effect of neonatal respiratory distress syndrome (NRDS). Altogether 137 cases of neonates with respiratory distress syndrome treated in our hospital from April 2016 to July 2018 were collected. Among them, 64 cases treated with noninvasive positive pressure ventilation were considered as the control group, and 73 cases treated with PS combined with noninvasive positive pressure ventilation were considered as the observation group. The expression of KRT-14 and ET-1 in the two groups was compared. The therapeutic effect, death, complications, and blood gas indexes PaO2, PaCO2, and PaO2/FiO2 in the two groups were compared. Receiver operating characteristic curve (ROC) was applied to analyze the diagnostic value of KRT-14 and ET-1 in the therapeutic effect of NRDS. The effective rate of the observation group was higher than that of the control group. After treatment, PaO2 and PaO2/FiO2 in both groups were notably higher than that before treatment, while PaCO2 was notably lower than that before treatment. And after treatment, the levels of PaO2 and PaO2/FiO2 in the observation group were remarkably higher than that in the control group; PaCO2 was notably lower than that in the control group. After treatment, the levels of KRT-14 and ET-1 in the two groups were remarkably lower than those before treatment, and the levels of KRT-14 and ET-1 in the observation group were considerably lower than those in the control group after treatment. ROC curve showed that the area under the curve (AUC) of KRT-14 was 0.791, and the AUC of ET-1 was 0.816. PS combined with noninvasive positive pressure ventilation can notably improve the therapeutic effect of NRDS. KRT-14 and ET-1 levels may be potential therapeutic diagnostic indicators.

Oxidative stress and diabetic retinopathy: Molecular mechanisms, pathogenetic role and therapeutic implications

Oxidative stress, a cytopathic outcome of excessive generation of ROS and the repression of antioxidant defense system for ROS elimination, is involved in the pathogenesis of multiple diseases, including diabetes and its complications. Retinopathy, a microvascular complication of diabetes, is the primary cause of acquired blindness in diabetic patients. Oxidative stress has been verified as one critical contributor to the pathogenesis of diabetic retinopathy. Oxidative stress can both contribute to and result from the metabolic abnormalities induced by hyperglycemia, mainly including the increased flux of the polyol pathway and hexosamine pathway, the hyper-activation of protein kinase C (PKC) isoforms, and the accumulation of advanced glycation end products (AGEs). Moreover, the repression of the antioxidant defense system by hyperglycemia-mediated epigenetic modification also leads to the imbalance between the scavenging and production of ROS. Excessive accumulation of ROS induces mitochondrial damage, cellular apoptosis, inflammation, lipid peroxidation, and structural and functional alterations in retina. Therefore, it is important to understand and elucidate the oxidative stress-related mechanisms underlying the progress of diabetic retinopathy. In addition, the abnormalities correlated with oxidative stress provide multiple potential therapeutic targets to develop safe and effective treatments for diabetic retinopathy. Here, we also summarized the main antioxidant therapeutic strategies to control this disease.

•

Oxidative stress can both contribute to and result from hyperglycemia-induced metabolic abnormalities in retina.

•

Genes important in regulation of ROS are epigenetically modified, increasing ROS accumulation in retina.

•

Oxidative stress is closely associated with the pathological changes in the progress of diabetic retinopathy.

•

Antioxidants ameliorate retinopathy through targeting multiple steps of oxidative stress.

Carotid body chemoreflex: a driver of autonomic abnormalities in sleep apnoea

What is the topic of this review? This article presents emerging evidence for heightened carotid body chemoreflex activity as a major driver of sympathetic activation and hypertension in sleep apnoea patients. What advances does it heighlight? This article discusses the recent advances on cellular, molecular and epigenetic mechanisms underlying the exaggerated chemoreflex in experimental models of sleep apnoea. The carotid bodies are the principal peripheral chemoreceptors for detecting changes in arterial blood oxygen concentration, and the resulting chemoreflex is a potent regulator of the sympathetic tone, blood pressure and breathing. Sleep apnoea is a disease of the respiratory system that affects several million adult humans. Apnoeas occur during sleep, often as a result of obstruction of the upper airway (obstructive sleep apnoea) or because of defective respiratory rhythm generation by the CNS (central sleep apnoea). Patients with sleep apnoea exhibit several co-morbidities, with the most notable among them being heightened sympathetic nerve activity and hypertension. Emerging evidence suggests that intermittent hypoxia resulting from periodic apnoea stimulates the carotid body, and the ensuing chemoreflex mediates the increased sympathetic tone and hypertension in sleep apnoea patients. Rodent models of intermittent hypoxia that simulate the O2 saturation profiles encountered during sleep apnoea have provided important insights into the cellular and molecular mechanisms underlying the heightened carotid body chemoreflex. This article describes how intermittent hypoxia affects the carotid body function and discusses the cellular, molecular and epigenetic mechanisms underlying the exaggerated chemoreflex.

Endothelin-2 Injures the Blood-Retinal Barrier and Macroglial Müller Cells: Interactions with Angiotensin II, Aldosterone, and NADPH Oxidase

Although increasing evidence indicates that endothelin-2 (Edn2) has distinct roles in tissue pathology, including inflammation, glial cell dysfunction, and angiogenesis, its role in the retina and the factors that regulate its actions are not fully understood. We hypothesized that Edn2 damages the blood-retinal barrier (BRB) and that this is mediated by interactions with the renin-angiotensin-aldosterone system and reactive oxygen species derived from NADPH oxidase (Nox). C57BL/6J mice received an intravitreal injection of Edn2 or control vehicle to examine the blood pressure-independent effects of Edn2. Mice administered Edn2 were randomized to receive by intraperitoneal injection treatments that inhibited the Edn type a receptor, Edn type b receptor, angiotensin type 1 receptor, mineralocorticoid receptor, or Nox isoforms 1 to 4. One month later, mice administered Edn2 exhibited breakdown of the BRB with increased vascular leakage, vascular endothelial growth factor expression, and infiltrating macrophages (Ly6C⁺CD45^highCD11b⁺). Further, macroglial Müller cells, which influence the integrity of the BRB and prevent retinal edema, became gliotic and expressed increased levels of water (aquaporin-4) and ion (Kir4.1) channels. This Edn2-mediated retinopathy was reduced by all treatments. Complementary in vitro studies in cultured Müller cells supported these findings and demonstrated the importance of reactive oxygen species in mediating these events. In conclusion, Edn2 has detrimental effects on the BRB and Müller cells that involve interactions with the renin-angiotensin aldosterone system and Nox1/4.

Inhibition of infarction-induced sympathetic innervation with endothelin receptor antagonism via a PI3K/GSK-3β-dependent pathway

Although endothelin (ET)-1 has been shown to upregulate nerve growth factor (NGF) expression, the molecular mechanisms are largely unknown. Phosphatidylinositol 3-kinase (PI3K)/Akt/glycogen synthase kinase (GSK)-3β signal has been implicated in the regulation of NGF. We investigated whether selective ET receptor blockers attenuated cardiac sympathetic reinnervation through restoring PI3K/Akt/GSK-3β activity. After ligation of the left anterior descending artery, male Wistar rats were randomized to either vehicle, atrasentan (an ET_A receptor antagonist) or A-192621 (an ET_B receptor antagonist) for 4 weeks. Sympathetic hyperinnervation after infarction was confirmed by myocardial norepinephrine measurement and immunofluorescent analysis. Post infarction was associated with increased reactive oxygen species (ROS), as measured by myocardial superoxide levels and dihydroethidine fluorescence staining. This was paralleled by a significant upregulation of NGF expression on mRNA and protein levels in the vehicle-treated rats, which reduced after administering atrasentan, not A-192621. Arrhythmic scores in the vehicle-treated rats were significantly higher than those treated with atrasentan. In an in vivo study atrasentan-induced decreased NGF was associated with activation of PI3K/Akt signaling pathway, which was further confirmed by the ex vivo study showing the restoration of NGF levels after coadministration of PI3K inhibitors (wortmannin and LY294002). Lithium chloride, an inhibitor of GSK-3β, did not provide additional attenuated NGF levels compared with atrasentan alone. Finally, atrasentan-attenuated NGF levels were reversed in the presence of peroxynitrite generator. ET_A receptor antagonism is a mediator to attenuate sympathetic hyperinnervation probably through restoration of PI3K/Akt/GSK-3β/ROS signaling pathway, a potential pharmacological target for arrhythmias after infarction.

H2S production by reactive oxygen species in the carotid body triggers hypertension in a rodent model of sleep apnea

Sleep apnea is a prevalent respiratory disease in which episodic cessation of breathing causes intermittent hypoxia. Patients with sleep apnea and rodents exposed to intermittent hypoxia exhibit hypertension. The carotid body senses changes in blood O2 concentrations, and an enhanced carotid body chemosensory reflex contributes to hypertension in sleep apnea patients. A rodent model of intermittent hypoxia that mimics blood O2 saturation profiles of patients with sleep apnea has shown that increased generation of reactive oxygen species (ROS) in the carotid body enhances the chemosensory reflex and triggers hypertension. CO generated by heme oxygenase-2 (HO-2) induces a signaling pathway that inhibits hydrogen sulfide (H2S) production by cystathionine γ-lyase (CSE), leading to suppression of carotid body activity. We found that ROS inhibited CO generation by HO-2 in the carotid body and liver through a mechanism that required Cys(265) in the heme regulatory motif of heterologously expressed HO-2. We showed that ROS induced by intermittent hypoxia inhibited CO production and increased H2S concentrations in the carotid body, which stimulated its neural activity. In rodents, blockade of H2S synthesis by CSE, by either pharmacologic or genetic approaches, inhibited carotid body activation and hypertension induced by intermittent hypoxia. Thus, our results indicate that oxidant-induced inactivation of HO-2, which leads to increased CSE-dependent H2S production in the carotid body, is a critical trigger of hypertension in rodents exposed to intermittent hypoxia.