Effect of endothelin-1 on the blood pressure response to acute hypoxia and hyperoxia in healthy young men.

Endothelin-1 (ET-1) and its receptors are linked to increases in sensitivity of the chemoreceptors to hypoxic stress and the development of hypertension in preclinical models. We hypothesized ET receptor antagonism would lower resting blood pressure (BP) as well as the acute BP response to chemoreflex stress. Twenty-four men (31 ± 5 years, 26 ± 3 kg/m2) completed two study visits (control, bosentan). On each visit, BP was assessed under three conditions: (1) normoxia (FiO2 0.21), (2) chemoreflex excitation via hypoxia (FiO2 0.05-0.21), (3) chemoreflex inhibition via hyperoxia (FiO2 1.00). Bosentan increased plasma ET-1 (0.94 ± 0.90 to 1.27 ± 0.62 pg/mL, p = 0.004), supporting receptor blockade. Resting diastolic (73 ± 5 to 69 ± 7 mmHg, p = 0.007) and mean (93 ± 7 to 88 ± 7 mmHg, p = 0.005) BP were reduced following bosentan compared to control with no change in systolic BP (p = 0.507). The mean BP response to both acute hypoxia (-0.48 ± 0.38 to -0.25 ± 0.31 mmHg/%, p = 0.004) and hyperoxia (area under the curve -93 ± 108 to -27 ± 66 AU, p = 0.018) were attenuated following bosentan. Acute ET receptor inhibition attenuates the rise in BP during chemoreflex excitation as well as the fall in BP during chemoreflex inhibition in healthy young men. These data support a role for ET-1 in control of resting BP, possibly through a chemoreceptor-mediated mechanism.

Secretion of GPNMB from Neural Stem Cells Induced by ET-1 Contributes to Angiogenesis after Spinal Cord Injury.

BACKGROUND: The feeble plasticity of spinal cord microvascular endothelial cells (SCMECs) after trauma is one of the major causes of spinal cord injury (SCI). Neural stem cells (NSCs) play an important role in nerve repair. Glycoprotein nonmetastatic B (GPNMB) has neuroprotective effects and can be stimulated by endothelin 1 (ET-1), and its expression is upregulated in SCI. Here, we aim to investigate whether elevated ET-1 levels stimulate NSCs to secrete GPNMB, thereby further promoting angiogenesis. METHODS: Mouse SCMECs and NSCs were isolated, cultured, and identified by flow cytometry and immunofluorescence staining. NSCs were treated with ET-1, while SCMECs were cocultured with NSCs, followed by treatment with ET-1. NCS and SCMEC viability were evaluated using cell counting kit 8 (CCK-8) assay, while cell proliferation, migration, invasion, and angiogenesis were examined using 5'-Ethynyl-2'-Deoxyuridine (EdU) staining, wound healing assay, Transwell assay, and tube formation assay. GPNMB expression in NCSs and SCMECs was quantified by western blot assay, quantitative Real-Time polymerase chain reaction (qRT-PCR), or enzyme-linked immunosorbent assay (ELISA). RESULTS: Mouse SCMECs and NSCs were successfully isolated and cultured. ET-1 promoted NSC viability and proliferation and upregulated GPNMB expression. NSCs and ET-1-treated NSCs promoted the viability, migration, invasion, angiogenesis, and GPNMB expression in SCMECs compared with control group cells, while GPNMB antibody reversed the above effects of ET-1 on the SCMECs. CONCLUSION: ET-1 promotes SCMEC migration and invasion, along with angiogenesis, by enhancing NSC-mediated GPNMB secretion, so ET-1 may be a novel therapeutic target for SCI.

Lycium barbarum glycopeptide promotes neuroprotection in ET-1 mediated retinal ganglion cell degeneration.

BACKGROUND: Vascular dysregulation is one of the major risk factors of glaucoma, and endothelin-1 (ET-1) may have a role in the pathogenesis of vascular-related glaucoma. Fruit extract from Lycium Barbarum (LB) exhibits anti-ageing and multitarget mechanisms in protecting retinal ganglion cells (RGC) in various animal models. To investigate the therapeutic efficacy of LB glycoproteins (LbGP) in ET-1 induced RGC degeneration, LbGP was applied under pre- and posttreatment conditions to an ET-1 mouse model. Retina structural and functional outcomes were characterised using clinical-based techniques. METHODS: Adult C57BL/6 mice were randomly allocated into four experimental groups, namely vehicle control (n = 9), LbGP-Pretreatment (n = 8), LbGP-Posttreatment (day 1) (n = 8) and LbGP-Posttreatment (day 5) (n = 7). Oral administration of LbGP 1 mg/Kg or PBS for vehicle control was given once daily. Pre- and posttreatment (day 1 or 5) were commenced at 1 week before and 1 or 5 days after intravitreal injections, respectively, and were continued until postinjection day 28. Effects of treatment on retinal structure and functions were evaluated using optical coherence tomography (OCT), doppler OCT and electroretinogram measurements at baseline, post-injection days 10 and 28. RGC survival was evaluated by using RBPMS immunostaining on retinal wholemounts. RESULTS: ET-1 injection in vehicle control induced transient reductions in arterial flow and retinal functions, leading to significant RNFL thinning and RGC loss at day 28. Although ET-1 induced a transient loss in blood flow or retinal functions in all LbGP groups, LbGP treatments facilitated better restoration of retinal flow and retinal functions as compared with the vehicle control. Also, all three LbGP treatment groups (i.e. pre- and posttreatments from days 1 or 5) significantly preserved thRNFL thickness and RGC densities. No significant difference in protective effects was observed among the three LbGP treatment groups. CONCLUSION: LbGP demonstrated neuroprotective effects in a mouse model of ET-1 induced RGC degeneration, with treatment applied either as a pretreatment, immediate or delayed posttreatment. LbGP treatment promoted a better restoration of retinal blood flow, and protected the RNFL, RGC density and retinal functions. This study showed the translational potential of LB as complementary treatment for glaucoma management.

Przewaquinone A inhibits Angiotensin II-induced endothelial diastolic dysfunction activation of AMPK.

BACKGROUND: Endothelial dysfunction (ED), characterized by markedly reduced nitric oxide (NO) bioavailability, vasoconstriction, and a shift toward a proinflammatory and prothrombotic state, is an important contributor to hypertension, atherosclerosis, and other cardiovascular diseases. Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) is widely involved in cardiovascular development. Przewaquinone A (PA), a lipophilic diterpene quinone extracted from Salvia przewalskii Maxim, inhibits vascular contraction. PURPOSE: Herein, the goal was to explore the protective effect of PA on ED in vivo and in vitro, as well as the underlying mechanisms. METHODS: A human umbilical vein endothelial cell (HUVEC) model of ED induced by angiotensin II (AngII) was used for in vitro observations. Levels of AMPK, endothelial nitric oxide synthase (eNOS), vascular cell adhesion molecule-1 (VCAM-1), nitric oxide (NO), and endothelin-1 (ET-1) were detected by western blotting and ELISA. A mouse model of hypertension was established by continuous infusion of AngII (1000 ng/kg/min) for 4 weeks using osmotic pumps. Following PA and/or valsartan administration, NO and ET-1 levels were measured. The levels of AMPK signaling-related proteins in the thoracic aorta were evaluated by immunohistochemistry. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were measured using the tail cuff method. Isolated aortic vascular tone measurements were used to evaluate the vasodilatory function in mice. Molecular docking, molecular dynamics, and surface plasmon resonance imaging (SPRi) were used to confirm AMPK and PA interactions. RESULTS: PA inhibited AngII-induced vasoconstriction and vascular adhesion as well as activated AMPK signaling in a dose-dependent manner. Moreover, PA markedly suppressed blood pressure, activated vasodilation in mice following AngII stimulation, and promoted the activation of AMPK signaling. Furthermore, molecular simulations and SPRi revealed that PA directly targeted AMPK. AMPK inhibition partly abolished the protective effects of PA against endothelial dysfunction. CONCLUSION: PA activates AMPK and ameliorates endothelial dysfunction during hypertension.

Sexual dimorphism of hypothalamic serotonin release during systemic inflammation: Role of endothelin-1.

The hypothalamus receives serotonergic projections from the raphe nucleus in a sex-specific manner. During systemic inflammation, hypothalamic levels of serotonin (5-hydroxytryptamine [5-HT]) decrease in male rats. The present study evaluated the involvement of endothelin-1 (ET-1) in the febrile response, hypolocomotion, and changes in hypothalamic 5-HT levels during systemic inflammation in male and female rats. An intraperitoneal injection of lipopolysaccharide (LPS) induced a febrile response and hypolocomotion in both male and female rats. However, although LPS reduced hypothalamic levels of 5-HT and its metabolite 5-hydroxyindol acetic acid (5-HIAA) in male rats, it increased these levels in female rats. An intracerebroventricular injection of the endothelin-B receptor antagonist BQ788 significantly reduced LPS-induced fever and hypolocomotion and changes in hypothalamic 5-HT and 5-HIAA levels in both male and female rats. The i.c.v. administration of ET-1 induced a significant fever and hypolocomotion, but reduced the hypothalamic levels of 5-HT and 5-HIAA in both males and females. These results suggest an important sexual dimorphism during systemic inflammation regarding the release of 5-HT in the hypothalamus. Moreover, ET-1 arises as an important mediator involved in the changes in hypothalamic 5-HT levels in both male and female rats.

Endothelin-1 down-regulates nuclear factor erythroid 2-related factor-2 and contributes to perivascular adipose tissue dysfunction in obesity.

Perivascular adipose tissue (PVAT) negatively regulates vascular muscle contraction. However, in the context of obesity, the PVAT releases vasoconstrictor substances that detrimentally affect vascular function. A pivotal player in this scenario is the peptide endothelin-1 (ET-1), which induces oxidative stress and disrupts vascular function. The present study postulates that obesity augments ET-1 production in the PVAT, decreases the function of the nuclear factor erythroid 2-related factor-2 (Nrf2) transcription factor, further increasing reactive oxygen species (ROS) generation, culminating in PVAT dysfunction. Male C57BL/6 mice were fed either a standard or a high-fat diet for 16 weeks. Mice were also treated with saline or a daily dose of 100 mg·kg-1 of the ETA and ETB receptor antagonist Bosentan, for 7 days. Vascular function was evaluated in thoracic aortic rings, with and without PVAT. Mechanistic studies utilized PVAT from all groups and cultured WT-1 mouse brown adipocytes. PVAT from obese mice exhibited increased ET-1 production, increased ECE1 and ETA gene expression, loss of the anticontractile effect, as well as increased ROS production, decreased Nrf2 activity, and downregulated expression of Nrf2-targeted antioxidant genes. PVAT of obese mice also exhibited increased expression of Tyr216-phosphorylated-GSK3ß and KEAP1, but not BACH1 - negative Nrf2 regulators. Bosentan treatment reversed all these effects. Similarly, ET-1 increased ROS generation and decreased Nrf2 activity in brown adipocytes, events mitigated by BQ123 (ETA receptor antagonist). These findings place ET-1 as a major contributor to PVAT dysfunction in obesity and highlight that pharmacological control of ET-1 effects restores PVAT's cardiovascular protective role.

Prognostic Value of Plasma Endothelin-1 in Predicting Worse Outcomes in Patients with Prediabetes and Diabetes and Stable Coronary Artery Diseases.

BACKGRUOUND: Endothelin-1 (ET-1) is an endogenous vasoconstrictor implicated in coronary artery disease (CAD) and diabetes. This study aimed to determine the prognostic value of ET-1 in the patients with stable CAD under different glucose metabolism states. METHODS: In this prospective, large-cohort study, we consecutively enrolled 7,947 participants with angiography-diagnosed stable CAD from April 2011 to April 2017. Patients were categorized by baseline glycemic status into three groups (normoglycemia, prediabetes, and diabetes) and further divided into nine groups by circulating ET-1 levels. Patients were followed for the occurrence of cardiovascular events (CVEs), including nonfatal myocardial infarction, stroke, and cardiovascular mortality. RESULTS: Of the 7,947 subjects, 3,352, 1,653, and 2,942 had normoglycemia, prediabetes, and diabetes, respectively. Over a median follow-up of 37.5 months, 381 (5.1%) CVEs occurred. The risk for CVEs was significantly higher in patients with elevated ET-1 levels after adjustment for potential confounders. When patients were categorized by both status of glucose metabolism and plasma ET-1 levels, the high ET-1 levels were associated with higher risk of CVEs in prediabetes (adjusted hazard ratio [HR], 2.089; 95% confidence interval [CI], 1.151 to 3.793) and diabetes (adjusted HR, 2.729; 95% CI, 1.623 to 4.588; both P<0.05). CONCLUSION: The present study indicated that baseline plasma ET-1 levels were associated with the prognosis in prediabetic and diabetic patients with stable CAD, suggesting that ET-1 may be a valuable predictor in CAD patients with impaired glucose metabolism.

Recurrent endothelin-1 mediated vascular insult leads to cognitive impairment protected by trophic factor pleiotrophin.

Vascular dementia (VaD) is a complex neurodegenerative condition, with cerebral small vessel dysfunctions as the central role in its pathogenesis. Given the lack of suitable animal models to study the disease pathogenesis, we developed a mouse model to closely emulate the clinical scenarios of recurrent transient ischemic attacks (TIAs) leading to VaD using vasoconstricting peptide Endothelin-1(ET-1). We observed that administration of ET-1 led to blood-brain barrier (BBB) disruption and detrimental changes in its components, such as endothelial cells and pericytes, along with neuronal loss and synaptic dysfunction, resulting in irreversible memory loss. Further, in our pursuit of understanding potential interventions, we co-administered pleiotrophin (PTN) alongside ET-1 injections. PTN exhibited remarkable efficacy in preserving vital components of the BBB, including endothelial cells and pericytes, thereby restoring BBB integrity, preventing neuronal loss, and enhancing memory function. Our findings give a valuable framework for understanding the detrimental effects of multiple TIAs on brain health and provide a useful animal model to explore VaD's underlying mechanisms further and pave the way for promising therapies.

[Effects of acupuncture on endothelial active factors and related autonomic neurotransmitters in spontaneous hypertension rats].

OBJECTIVE: To observe the effects of acupuncture at "antihypertensive acupoint prescription" on endothelial active factors and related autonomic neurotransmitters in spontaneous hypertension rats, and explore the vascular regulation and central regulation mechanisms of acupuncture for anti-hypertension. METHODS: Thirty SPF grade male spontaneous hypertension rats were randomly divided into a model group (15 rats) and an acupuncture group (15 rats). Besides, 15 Wistar Kyoto rats were collected as a blank control group (normal group). In the acupuncture group, acupuncture was delivered at the "antihypertensive acupoint prescription" (bilateral "Renying" [ST 9], "Quchi" [LI 11], "Zusanli" [ST 36], "Taichong" [LR 3] and "Neiguan" [PC 6]), with needles retained for 30 min, once daily. The duration of intervention was 28 days. Every week, using the the irritation scale, the sign of sympathetic irritation was evaluated dynamically. The arterial blood pressure of the rats tail was determined, using non-invasive blood pressure measurement system. ELISA was adopted to detect the levels of calcitonin gene-related peptide (CGRP), nitric oxide (NO), endothelin-1 (ET-1), neuropeptide Y (NPY) in the serum. DAB chromogenic in situ hybridization (CISH) was provided to detect the mRNA expression of endothelial nitric oxide synthase (eNOS) in the internal carotid artery and the arcuate nucleus (ARC), and that of CGRP in the paraventricular nucleus posterior (PVP) and the ventrolateral medulla (VLM). Liquid chromatography-mass spectrometry (LC-MS) was used to detect the levels of epinephrine (E) and norepinephrine (NE) in the paraventricular nucleus anterior (PVA). RESULTS: Compared with the normal group, the irritation scores, systolic blood pressure and diastolic blood pressure were increased at each time point in the model group (P<0.05). When compared with the model group, the irritation scores after the intervention for 3 and 4 weeks, and systolic and diastolic blood pressure after intervention for 2, 3 and 4 weeks were reduced in the acupuncture group (P<0.05). In comparison with the normal group, the serum CGRP and NO levels of the rats were decreased (P<0.05), and the serum ET-1 and NPY levels, as well as E and EN levels in PVA were increased (P<0.05) in the model group. The levels of serum CGRP and NO were elevated (P<0.05), and the serum ET-1 and NPY levels, as well as E and EN levels of PVA were reduced (P<0.05) in the acupuncture group when compared with those of the model group. In the model group, the media of internal carotid artery exhibited thickening and remodeling, while the neuron volume in ARC was small. In the acupuncture group, every layer of internal carotid artery was acceptably arranged, and the parvicellular neuron of ARC was moderate in volume. For the in situ hybridization of eNOS mRNA for the rats of each group, the smooth muscle cells were predominantly expressed in each layer of the internal carotid artery, whereas the expression of parvicellular neurons was dominated in ARC. In the model group, the large and small neurosecretory cells were distributed sparsely in the nerves of PVP; in the acupuncture group, the cells of these two species were distributed regularly; and there were few species of glial cell in the VLM of either the model group or the acupuncture group. In each group, for the in situ hybridization of CGRP mRNA, the small neurosecretory cells were expressed predominately in the PVP, while, the expression of glial cell nuclei and the cell cytoplasm was dominated in the VLM. Compared with the normal group, the mRNA expression of eNOS in the internal carotid artery and ARC and that of CGRP mRNA in the PVP and VLM was decreased in the model group (P<0.05). In the acupuncture group, when compared with the model group, the mRNA expression of eNOS in the internal carotid artery and ARC and that of CGRP in the PVP and VLM was increased in the acupuncture group (P<0.05). CONCLUSION: Acupuncture at "antihypertensive acupoint prescription" can upregulate the level of vascular relaxing factors, downregulate the level of contracting factors, enhance the response of relaxing factors in targeting blood vessels and regulating the center. The mechanism may be related to the modulation of the sympathetic-adrenergic autonomic neurotransmitters in the paraventricular nucleus in spontaneous hypertension rats.

Levels of Plasma Endothelin-1, Circulating Endothelial Cells, Endothelial Progenitor Cells, and Cytokines after Cardiopulmonary Bypass in Children with Congenital Heart Disease: Role of Endothelin-1 Regulation.

Congenital heart disease (CHD) can be complicated by pulmonary arterial hypertension (PAH). Cardiopulmonary bypass (CPB) for corrective surgery may cause endothelial dysfunction, involving endothelin-1 (ET-1), circulating endothelial cells (CECs), and endothelial progenitor cells (EPCs). These markers can gauge disease severity, but their levels in children's peripheral blood still lack consensus for prognostic value. The aim of our study was to investigate changes in ET-1, cytokines, and the absolute numbers (Ɲ) of CECs and EPCs in children 24 h before and 48 h after CPB surgery to identify high-risk patients of complications. A cohort of 56 children was included: 41 cases with CHD-PAH (22 with high pulmonary flow and 19 with low pulmonary flow) and 15 control cases. We observed that Ɲ-CECs increased in both CHD groups and that Ɲ-EPCs decreased in the immediate post-surgical period, and there was a strong negative correlation between ET-1 and CEC before surgery, along with significant changes in ET-1, IL8, IL6, and CEC levels. Our findings support the understanding of endothelial cell precursors' role in endogenous repair and contribute to knowledge about endothelial dysfunction in CHD.

Antibody to Endogenous Cardiotonic Steroid Reverses Vascular Fibrosis and Restores Vasorelaxation in Chronic Kidney Disease.

Marinobufagenin (MBG) is implicated in chronic kidney disease, where it removes Fli1-induced inhibition of the collagen-1. We hypothesized that (i) in nephrectomized rats, aortic fibrosis develops due to elevated plasma MBG and inhibited Fli1, and (ii) that the antibody to MBG reduces collagen-1 and improves vasodilatation. A partial nephrectomy was performed in male Sprague-Dawley rats. Sham-operated animals comprised the control group. At 5 weeks following nephrectomy, rats were administered the vehicle (n = 8), or the anti-MBG antibody (n = 8). Isolated aortic rings were tested for their responsiveness to sodium nitroprusside following endothelin-1-induced constriction. In nephrectomized rats, there was an increase in the intensity of collagen staining in the aortic wall vs. the controls. In antibody-treated rats, the structure of bundles of collagen fibers had ordered organization. Western blots of the aorta had lower levels of Fli1 (arbitrary units, 1 ± 0.05 vs. 0.2 ± 0.01; p < 0.001) and greater collagen-1 (arbitrary units, 1 ± 0.01 vs. 9 ± 0.4; p < 0.001) vs. the control group. Administration of the MBG antibody to rats reversed the effect of the nephrectomy on Fli1 and collagen-1 proteins. Aortic rings pretreated with endothelin-1 exhibited 50% relaxation following the addition of sodium nitroprusside (EC50 = 0.28 µmol/L). The responsiveness of the aortic rings obtained from nephrectomized rats was markedly reduced (EC50 = 3.5 mol/L) compared to the control rings. Treatment of rats with the antibody restored vasorelaxation. Thus, the anti-MBG antibody counteracts the Fli1-collagen-1 system and reduces aortic fibrosis.

Exploring the roles and therapeutic implications of melatonin-mediated KLF6 in the development of intracranial aneurysm.

BACKGROUND: Intracranial aneurysm (IA) is a cerebrovascular disease with a high mortality rate due to ruptured subarachnoid hemorrhage. While Krüppel-like factor 6 (KLF6) dysregulation has been implicated in cancer and cardiovascular diseases, its role in IA remains unclear. MATERIALS AND METHODS: The GSE122897 and GSE15629 datasets were downloaded from the Gene Expression Omnibus database. Immune cell infiltration and hypoxia analysis were performed to explore the effects of KLF6 on IA. Weighted gene co-expression network analysis was used to identify hub genes related to KLF6 expression for subsequent analyses. Hypoxia-related genes were identified. Drug prediction was performed for IA. Samples from healthy individuals and patients with IA were collected to detect the expression of endothelin-1 (ET-1), vascular hematoma factor (vWF), and KLF6. A model of H2O2-induced human brain vascular smooth muscle cells (HBVSMC) injury was constructed to explore the effects of KLF6 and melatonin to treat IA. RESULTS: T cells CD4 memory resting and monocytes were significantly different in the KLF6 high and low expression groups. Four hypoxia-related gene sets were significantly enriched in the KLF6 high-expression group. Six hypoxia-related hub genes were obtained, which were significantly associated with KLF6. Drug prediction showed that melatonin may be a potential drug for IA. The levels of ET-1, vWF, and KLF6 were significantly upregulated in patients with IA. KLF6 exacerbates H2O2-induced injury in HBVSMC, ameliorated by melatonin. CONCLUSION: KLF6 may be a potential target for IA treatment, with melatonin-mediated KLF6 effects playing a crucial role in the development of IA.

KLF6 was associated with infiltrated immune cells and hypoxia genes in intracranial aneurysm.KLF6 was significantly upregulated in patients with intracranial aneurysm.KLF6 exacerbates H₂O₂-induced injury in HBVSMC, ameliorated by melatonin.

Endothelin-1 (ET-1) contributes to senescence and phenotypic changes in brain pericytes in diabetes-mimicking conditions.

Diabetes mediates endothelial dysfunction and increases the risk of Alzheimer's disease and related dementias. Diabetes also dysregulates the ET system. ET-1-mediated constriction of brain microvascular pericytes (BMVPCs) has been shown to contribute to brain hypoperfusion. Cellular senescence, a process that arrests the proliferation of harmful cells and instigates phenotypical changes and proinflammatory responses in endothelial cells that impact their survival and function. Thus, we hypothesized that ET-1 mediates BMVPC senescence and phenotypical changes in diabetes-like conditions. Human BMVPCs were incubated in diabetes-like conditions with or without ET-1 (1 µmol/L) for 3 and 7 days. Hydrogen peroxide (100 µmol/L H2O2) was used as a positive control for senescence and to mimic ischemic conditions. Cells were stained for senescence-associated ß-galactosidase or processed for immunoblotting and quantitative real-time PCR analyses. In additional experiments, cells were stimulated with ET-1 in the presence or absence of ETA receptor antagonist BQ-123 (20 µmol/L) or ETB receptor antagonist BQ-788 (20 µmol/L). ET-1 stimulation increased ß-galactosidase accumulation which was prevented by BQ-123. ET-1 also increased traditional senescence marker p16 protein and pericyte-specific senescence markers, TGFB1i1, PP1CA, and IGFBP7. Furthermore, ET-1 stimulated contractile protein α-SMA and microglial marker ostepontin in high glucose suggesting a shift toward an ensheathing or microglia-like phenotype. In conclusion, ET-1 triggers senescence, alters ETA and ETB receptors, and causes phenotypical changes in BMVPCs under diabetes-like conditions. These in vitro findings need to be further studied in vivo to establish the role of ETA receptors in the progression of pericyte senescence and phenotypical changes in VCID.

Ribosomal S6 kinase signaling regulates neuronal viability during development and confers resistance to excitotoxic cell death in mature neurons.

The Ribosomal S6 Kinase (RSK) family of serine/threonine kinases function as key downstream effectors of the MAPK signaling cascade. In the nervous system, RSK signaling plays crucial roles in neuronal development and contributes to activity-dependent neuronal plasticity. This study examined the role of RSK signaling in cell viability during neuronal development and in neuroprotection in the mature nervous system. Using neuronal cell-culture-based profiling, we found that suppressing RSK signaling led to significant cell death in developing primary neuronal cultures. To this end, treatment with the RSK inhibitors BiD1870 or SL0101 on the first day of culturing resulted in over 80% cell death. In contrast, more mature cultures showed attenuated cell death upon RSK inhibition. Inhibition of RSK signaling during early neuronal development also disrupted neurite outgrowth and cell growth. In maturing hippocampal explant cultures, treatment with BiD1870 had minimal effects on cell viability, but led to a striking augmentation of NMDA-induced cell death. Finally, we used the endothelin 1 (ET-1) model of ischemia to examine the neuroprotective effects of RSK signaling in the mature hippocampus in vivo. Notably, in the absence of RSK inhibition, the granule cell layer (GCL) was resistant to the effects of ET-1; However, disruption of RSK signaling (via the microinjection of BiD1870) prior to ET-1 injection triggered cell death within the GCL, thus indicating a neuroprotective role for RSK signaling in the mature nervous system. Together these data reveal distinct, developmentally-defined, roles for RSK signaling in the nervous system.

Endothelin-1 Plasma and Aqueous Humor Levels in Different Types of Glaucoma: A Systematic Review and Meta-Analysis.

Background and Objectives: Several studies suggest the complex relationship between Endothelin-1 (ET-1) levels with various types of glaucoma. This systematic review and meta-analysis explore ET-1 levels in plasma and aqueous humor among different types of glaucoma. Materials and Methods: A literature search (PubMed, ScienceDirect, Cochrane Library) was made up to April 2024 (PROSPERO: CRD42023430471). The results were synthesized according to PRISMA Guidelines. Results were presented as standardized mean differences (SMD) with 95% confidence intervals (CI). Results: A total of 2597 subjects (1513 patients with glaucoma vs. 1084 healthy controls) from 23 studies were included in a meta-analysis. Notably, patients with glaucoma reported significantly higher plasma levels of ET-1 compared to controls (SMD: 1.21, 95% CI: 0.59-1.82, p < 0.001). Particularly, plasma ET-1 levels were higher in primary open-angle glaucoma (POAG) (SMD: 0.87, 95% CI: 0.09-1.65, p < 0.05), normal-tension glaucoma (SMD: 0.86, 95% CI: 0.27-1.46, p = 0.05), and angle-closure glaucoma patients (SMD: 1.03, 95% CI: 0.43-1.63, p < 0.001) compared to healthy controls. Moreover, ET-1 aqueous humor levels were significantly higher in patients with glaucoma compared to controls (SMD: 1.60, 95% CI: 1.04-2.15, p < 0.001). In particular, aqueous humor levels were higher in POAG patients (SMD: 2.03 95% CI: 1.00-3.14, p < 0.001), and pseudoexfoliative glaucoma patients (SMD: 2.03, 95% CI: 1.00-3.07, p < 0.001) compared to controls. Conclusions: This meta-analysis indicates that elevated levels of ET-1 plasma and aqueous humor are significantly associated with different types of glaucoma. The pathogenesis of ET-1-related mechanisms may vary across different glaucoma types, indicating that possible therapeutic approaches targeting ET-1 pathways should be tailored to each specific glaucoma type.

Effects of Bosentan on Hypoxia, Inflammation and Oxidative Stress in Experimental Blunt Thoracic Trauma Model.

Background and Objectives: In this study, we aimed to investigate the effects of bosentan, an endothelin receptor antagonist, on endothelin-1 (ET-1), hypoxia-inducible factor-1 (HIF-1), nuclear factor-kappa B (NF-κB), and tumor necrosis factor (TNF)-α as inflammation markers, pro-oxidant antioxidant balance (PAB), and total antioxidant capacity (TAC) levels as oxidative stress parameters in lung tissues of rats in an experimental model of pulmonary contusion (PC) induced by blunt thoracic trauma. Materials and Methods: Thirty-seven male Sprague-Dawley rats were divided into five groups. C: The control group (n = 6) consisted of unprocessed and untreated rats. PC3 (n = 8) underwent 3 days of PC. PC-B3 (n = 8) received 100 mg/kg bosentan and was given orally once a day for 3 days. The PC7 group (n = 7) underwent 7 days of PC, and PC-B7 (n = 8) received 100 mg/kg bosentan and was given orally once a day for 7 days. Results: ET-1, NF-κB, TNF-α, HIF-1α, and PAB levels were higher, while TAC activity was lower in all groups compared with the control (p < 0.05). There was no significant difference in ET-1 and TNF-α levels between the PC-B3 and PC-B7 groups and the control group (p < 0.05), while NF-κB, HIF-1α, and PAB levels were still higher in both the PC-B3 and PC-B7 groups than in the control group. Bosentan decreased ET-1, NF-κB, TNF-α, HIF-1α, and PAB and increased TAC levels in comparison to the nontreated groups (p < 0.05). Conclusions: Bosentan decreased the severity of oxidative stress in the lungs and reduced the inflammatory reaction in rats with PC induced by blunt thoracic trauma. This suggests that bosentan may have protective effects on lung injury mechanisms by reducing hypoxia, inflammation, and oxidative stress. If supported by similar studies, bosentan can be used in both pulmonary and emergency clinics to reduce ischemic complications, inflammation, and oxidative stress in some diseases that may be accompanied by ischemia.

Endothelin-1 influences mechanical properties and contractility of hiPSC derived cardiomyocytes resulting in diastolic dysfunction.

A better understanding of the underlying pathomechanisms of diastolic dysfunction is crucial for the development of targeted therapeutic options with the aim to increase the patients' quality of life. In order to shed light on the processes involved, suitable models are required. Here, effects of endothelin-1 (ET-1) treatment on cardiomyocytes derived from human induced pluripotent stem cells (hiPSCs) were investigated. While it is well established, that ET-1 treatment induces hypertrophy in cardiomyocytes, resulting changes in cell mechanics and contractile behavior with focus on relaxation have not been examined before. Cardiomyocytes were treated with 10 nM of ET-1 for 24 h and 48 h, respectively. Hypertrophy was confirmed by real-time deformability cytometry (RT-DC) which was also used to assess the mechanical properties of cardiomyocytes. For investigation of the contractile behavior, 24 h phase contrast video microscopy was applied. To get a deeper insight into changes on the molecular biological level, gene expression analysis was performed using the NanoString nCounter® cardiovascular disease panel. Besides an increased cell size, ET-1 treated cardiomyocytes are stiffer and show an impaired relaxation. Gene expression patterns in ET-1 treated hiPSC derived cardiomyocytes showed that pathways associated with cardiovascular diseases, cardiac hypertrophy and extracellular matrix were upregulated while those associated with fatty acid metabolism were downregulated. We conclude that alterations in cardiomyocytes after ET-1 treatment go far beyond hypertrophy and represent a useful model for diastolic dysfunction.

Characterizing the Linkage of Systemic Hypoxia and Angiogenesis in High-Grade Glioma to Define the Changes in Tumor Microenvironment for Predicting Prognosis.

High-grade gliomas (HGG) comprising WHO grades 3 and 4 have a poor overall survival (OS) that has not improved in the past decade. Herein, markers representing four components of the tumor microenvironment (TME) were identified to define their linked expression in TME and predict the prognosis in HGG, namely, interleukin6 (IL6, inflammation), inducible nitric oxide synthase(iNOS), heat shock protein-70 (HSP70, hypoxia), vascular endothelial growth receptor (VEGF), and endothelin1 (ET1) (angiogenesis) and matrix metalloprotease-14 (MMP14) and intercellular adhesion molecule1 (ICAM1, extracellular matrix). To establish a non-invasive panel of biomarkers for precise prognostication in HGG. Eighty-six therapy-naive HGG patients with 45 controls were analyzed for the defined panel. Systemic expression of extracellular/secretory biomarkers was screened dot-immune assay (DIA), quantified by ELISA, and validated by immunocytochemistry (ICC). Expression of iNOS, HSP70, IL-6, VEGF, ET1, MMP14, and ICAM1 was found to be positively associated with grade. Quantification of circulating levels of the markers by ELISA and ICC presented a similar result. The biomarkers were observed to negatively correlate with OS (p < 0.0001). Cox-regression analysis yielded all biomarkers as good prognostic indicators and independent of confounders. On applying combination statistics, the biomarker panel achieved higher sensitivity than single markers to define survival. The intra-association of all seven biomarkers was significant, hinting of a cross-talk between the TME components and a hypoxia driven systemic inflammation upregulating the expression of other components. This is a first ever experimental study of a marker panel that can distinguish between histopathological grades and also delineate differential survival using liquid biopsy, suggesting that markers of hypoxia can be a cornerstone for personalized therapy. The panel of biomarkers of iNOS, HSP70, IL-6, VEGF, ET1, MMP14, and ICAM1 holds promise for prognostication in HGG.

Indigo Leaves-Induced Pulmonary Arterial Remodeling without Right Ventricular Hypertrophy in Rats.

Indigo naturalis (IN), derived from the leaves of the indigo plant, is a traditional Chinese medicine that has historically been used for its anti-inflammatory properties in the treatment of various diseases, including ulcerative colitis (UC). However, long-term use of IN in UC patients is incontrovertibly associated with the onset of pulmonary arterial hypertension (PAH). To investigate the mechanisms by which IN induces PAH, we focused on the raw material of IN, indigo leaves (IL). Only the condition of long-term chronic (6 months) and high-dose (containing 5% IL in the control diet) administration of IL induced medial thickening in the pulmonary arteries without right ventricular hypertrophy in our rat model. IL administration for a month did not induce pulmonary arterial remodeling but increased endothelin-1 (ET-1) expression levels within endothelial cell (EC) layers in the lungs. Gene Expression Omnibus analysis showed that ET-1 is a key regulator of PAH and that the IL component indican and its metabolite IS induced ET-1 mRNA expression via reactive oxygen species-dependent mechanism. We identified the roles of indican and IS in ET-1 expression in ECs, which were linked to pulmonary arterial remodeling in an animal model.

Prognostic value of plasma big endothelin-1 in patients with light chain cardiac amyloidosis.

BACKGROUND: Light chain cardiac amyloidosis (AL-CA) is associated with a high incidence of mortality. Big endothelin-1 (ET-1), the precursor of endothelial-vasoconstrictive ET-1, is closely related to the concentration of bioactive ET-1. Association between big ET-1 and prognosis of AL-CA has not yet been documented. The purpose of this study was to evaluate the prognostic value of big ET-1 for poor outcomes in moderate to severe AL-CA. METHODS: Big ET-1 levels were determined on admission in patients with newly diagnosed AL-CA with modified Mayo 2004 stage II or III. Primary outcome was all-cause mortality. The secondary outcomes included death from cardiac cause and the composite of the primary outcome or hospitalisations due to worsening heart failure. RESULTS: Overall, 141 patients were retrospectively included (57 stage II, 34 stage IIIa, 50 stage IIIb). During a median follow-up time of 25.7 months, 84 (59.6%) patients died. Patients with big ET-1 levels of ≤0.88 pmol/L had longer survival than those with >0.88 pmol/L (median survival time: 34.1 months vs 15.3 months, log-rank p<0.001), which was also observed in the validation cohort (log-rank p=0.026). Higher big ET-1 levels were predictive for all-cause mortality after multivariable adjustment (HR 1.91, 95% CI 1.05 to 3.49, p=0.035). Big ET-1 levels added an incremental prognostic value over modified Mayo 2004 stage (C-index: from 0.671 to 0.696, p=0.025; integrated discrimination improvement 0.168, p=0.047). CONCLUSIONS: Big ET-1 is a strong and independent predictor of mortality in patients with moderate to severe AL-CA, which may indicate a possible role for risk stratification in patients with this disease.