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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.

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Background and objectives: Endothelin-1 (ET-1) and transforming growth factor-ß (TGF-ß) play a pivotal role in the pathophysiology and vascular remodeling of chronic thromboembolic pulmonary hypertension (CTEPH) which is an under-diagnosed complication of acute pulmonary embolism (PE). Currently, pulmonary endarterectomy (PEA) is still the treatment of choice for selected patients suffering from CTEPH. The aim of this study was to evaluate the preoperative and postoperative circulating levels of ET-1 and TGF-ß in subjects affected by CTEPH undergoing successful surgical treatment by PEA. Methods: The data from patients diagnosed with CTEPH who underwent PEA at the Foundation IRCCS Policlinico San Matteo Hospital (Pavia, Italy) were prospectively recorded in the Institutional database. Circulating ET-1 and TGF-ß levels were assessed by an ELISA commercial kit before PEA, at 3 months and 1 year after PEA. The demographic data, preoperatory mean pulmonary arterial pressure (mPAP), cardiac output (CO), and pulmonary vascular resistance (PVR) were also recorded. Univariate and multivariate analyses were performed. Results: The analysis included 340 patients with complete ET-1 measurements and 206 patients with complete TGF-ß measurements. ET-1 significantly decreased both at 3 months (p < 0.001) and at 1 year (p = 0.009) after PEA. On the other hand, preoperatory TGF-ß levels did not significantly change after PEA. Furthermore, ET-1, but not TGF-ß, was a good predictor for increased mPAP in multivariate analyses (p < 0.05). Conclusions: ET-1 but not TGF ß was significantly modulated by PEA in subjects affected by CTEPH up to 1 year after surgery. The mechanisms leading to prolonged elevated circulating TGF-ß levels and their clinical significance have to be further elucidated.

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Purpose: Age-related macular degeneration (AMD) presents a multifaceted etiopathogenesis involving ischemic, inflammatory, and genetic components. This study investigates the correlation between ocular hemodynamics, scleral rigidity (SR), and plasma endothelin-1 (ET1) levels in treatment-naive patients with asymmetrical AMD. Patients and Methods: This study included 20 treatment-naive patients (12 females and 8 males) with an average age of 76.4 ± 3.7 years, who presented with AMD with neovascular membrane formation (nAMD) in one eye, and intermediate grade 2 AMD (iAMD) in the other eye. The control group consisted of 20 healthy subjects (13 females and 7 males) with a mean age of 74.7 ± 3.9 years. All patients and healthy controls underwent color Doppler imaging (i) of the ophthalmic artery (OA), short posterior ciliary arteries (SPCAs), and central retinal artery (CRA); Plasma ET-1 levels were measured for all patients and healthy subjects. Corneal biomechanics were assessed using an Ocular Response Analyzer and two indices were obtained: corneal hysteresis (CH) and corneal resistance factor (CRF). Results: Results showed reduced blood flow velocities and increased resistance indices in AMD eyes, particularly affecting the short posterior ciliary arteries. According to mechanical theory, ARMD eyes exhibited elevated scleral rigidity and corneal resistance factor compared to controls, with a notable rise in SR in neovascular AMD (nAMD) eyes. As per the chronic subacute inflammation theory, plasma ET-1 levels were significantly higher in AMD patients, correlating with abnormal SPCAs blood flow and increased resistance indices. Conclusion: Findings suggest a multifactorial etiology of AMD involving an increase of ET-1 plasma levels with biomechanic damages of corneal and scleral tissue in nAMD.

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Current ischemic models strive to replicate ischemia-mediated injury. However, they face challenges such as inadequate reproducibility, difficulties in translating rodent findings to humans, and ethical, financial, and practical constraints that limit the accuracy of extensive research. This study introduces a novel approach to inducing persistent ischemia in 3-day-old chicken embryos using endothelin-1. The protocol targets the right vitelline arteries, validated with Doppler blood flow imaging and molecular biology experiments. This innovative approach facilitates the exploration of oxidative stress, inflammatory responses, cellular death, and potential drug screening suitability utilizing a 3-day-old chicken embryo. Key features • This model enables the evaluation and investigation of the pathology related to persistent ischemia • This model allows for the assessment of parameters like oxidative stress, inflammation, and cellular death • This model enables quantification of molecular changes at the nucleic acid and protein levels • This model allows for the efficient screening of drugs and their targets Graphical overview.

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Parallel to the increasing prevalence of obesity in the world, the mortality from cardiovascular disease has also increased. Low-grade chronic inflammation in obesity disrupts vascular homeostasis, and the dysregulation of adipocyte-derived endocrine and paracrine effects contributes to endothelial dysfunction. Besides the adipose tissue inflammation, decreased nitric oxide (NO)-bioavailability, insulin resistance (IR), and oxidized low-density lipoproteins (oxLDLs) are the main factors contributing to endothelial dysfunction in obesity and the development of cardiorenal metabolic syndrome. While normal healthy perivascular adipose tissue (PVAT) ensures the dilation of blood vessels, obesity-associated PVAT leads to a change in the profile of the released adipo-cytokines, resulting in a decreased vasorelaxing effect. Higher stiffness parameter ß, increased oxidative stress, upregulation of pro-inflammatory cytokines, and nicotinamide adenine dinucleotide phosphate (NADP) oxidase in PVAT turn the macrophages into pro-atherogenic phenotypes by oxLDL-induced adipocyte-derived exosome-macrophage crosstalk and contribute to the endothelial dysfunction. In clinical practice, carotid ultrasound, higher leptin levels correlate with irisin over-secretion by human visceral and subcutaneous adipose tissues, and remnant cholesterol (RC) levels predict atherosclerotic disease in obesity. As a novel therapeutic strategy for cardiovascular protection, liraglutide improves vascular dysfunction by modulating a cyclic adenosine monophosphate (cAMP)-independent protein kinase A (PKA)-AMP-activated protein kinase (AMPK) pathway in PVAT in obese individuals. Because the renin-angiotensin-aldosterone system (RAAS) activity, hyperinsulinemia, and the resultant IR play key roles in the progression of cardiovascular disease in obesity, RAAS-targeted therapies contribute to improving endothelial dysfunction. By contrast, arginase reciprocally inhibits NO formation and promotes oxidative stress. Thus, targeting arginase activity as a key mediator in endothelial dysfunction has therapeutic potential in obesity-related vascular comorbidities. Obesity-related endothelial dysfunction plays a pivotal role in the progression of type 2 diabetes (T2D). The peroxisome proliferator-activated receptor gamma (PPARγ) agonist, rosiglitazone (thiazolidinedione), is a popular drug for treating diabetes; however, it leads to increased cardiovascular risk. Selective sodium-glucose co-transporter-2 (SGLT-2) inhibitor empagliflozin (EMPA) significantly improves endothelial dysfunction and mortality occurring through redox-dependent mechanisms. Although endothelial dysfunction and oxidative stress are alleviated by either metformin or EMPA, currently used drugs to treat obesity-related diabetes neither possess the same anti-inflammatory potential nor simultaneously target endothelial cell dysfunction and obesity equally. While therapeutic interventions with glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide or bariatric surgery reverse regenerative cell exhaustion, support vascular repair mechanisms, and improve cardiometabolic risk in individuals with T2D and obesity, the GLP-1 analog exendin-4 attenuates endothelial endoplasmic reticulum stress.

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OBJECTIVE: This article reviews the published data including the pharmacology, efficacy, and safety of aprocitentan, a novel endothelin receptor antagonist developed to treat hypertension in conjunction with additional agents. DATA SOURCES: A literature search was conducted from drug discovery until May 2024 through PubMed, MEDLINE, and National Institutes of Health Clinical Trials Registry utilizing the following search terms: Tryvio, aprocitentan, hypertension, resistant hypertension, endothelin receptor antagonist, and ACT-132577. STUDY SELECTION AND DATA EXTRACTION: All relevant English-language studies, or studies that could be appropriately translated into English, containing the pharmacology, pharmacokinetics, safety, and efficacy of aprocitentan, were selected for review. DATA SYNTHESIS: In the setting of resistant hypertension, aprocitentan has shown significant reductions in blood pressure in both medical office and 24-hour ambulatory settings at 4 weeks with a sustained effect at 40 weeks. Studies evaluating cardiovascular risk reduction have not been conducted at this time. Fluid retention and edema were the most frequent adverse events reported in clinical studies with aprocitentan. As a class, endothelin receptor antagonists may cause fetal harm; aprocitentan should be used with caution to avoid embryo-fetal toxicity. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE IN COMPARISON TO EXISTING DRUGS: Owing to the existent barriers for the treatment of resistant hypertension, aprocitentan presents itself as an effective option when added to traditional antihypertensives. This single-strength, once-daily regimen may serve as an appealing option to both patients and prescribers. CONCLUSION: Aprocitentan is a safe and effective medication for the treatment of hypertension when added to other pharmacological therapies.

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Background: 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.

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Na+-K+-2Cl- cotransporter-1 (NKCC1) is present in brain cells, including astrocytes. The expression of astrocytic NKCC1 increases in the acute phase of traumatic brain injury (TBI), which induces brain edema. Endothelin-1 (ET-1) is a factor that induces brain edema and regulates the expression of several pathology-related genes in astrocytes. In the present study, we investigated the effect of ET-1 on NKCC1 expression in astrocytes. ET-1 (100 nM)-treated cultured astrocytes showed increased NKCC1 mRNA and protein levels. The effect of ET-1 on NKCC1 expression in cultured astrocytes was reduced by BQ788 (1 µM), an ETB antagonist, but not by FR139317 (1 µM), an ETA antagonist. The involvement of ET-1 in NKCC1 expression in TBI was examined using a fluid percussion injury (FPI) mouse model that replicates the pathology of TBI with high reproducibility. Administration of BQ788 (15 nmol/day) decreased FPI-induced expressions of NKCC1 mRNA and protein, accompanied with a reduction of astrocytic activation. FPI-induced brain edema was attenuated by BQ788 and NKCC1 inhibitors (azosemide and bumetanide). ET-1-treated cultured astrocytes showed increased mRNA and protein expression of hypoxia-inducible factor-1α (HIF1α). Immunohistochemical observations of mouse cerebrum after FPI showed co-localization of HIF1α with GFAP-positive astrocytes. Increased HIF1α expression in the TBI model was reversed by BQ788. FM19G11 (an HIF inhibitor, 1 µM) and HIF1α siRNA suppressed ET-induced increase in NKCC1 expression in cultured astrocytes. These results indicate that ET-1 increases NKCC1 expression in astrocytes through the activation of HIF1α.

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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.

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BACKGROUND AND PURPOSE: Endothelin-1 (ET-1) receptor A (ETA) antagonists reduce proteinuria and prevent renal outcomes in chronic kidney disease (CKD) patients, but their utility has been limited because of associated fluid retention, resulting in increased heart failure risk. Understanding the mechanisms responsible for fluid retention could result in solutions that preserve renoprotective effects while mitigating fluid retention, but the complexity of the endothelin system has made identification of the underlying mechanisms challenging. APPROACH: We utilized a previously developed mathematical model of ET-1 kinetics, ETA receptor antagonism, kidney function, haemodynamics, and sodium and water homeostasis to evaluate hypotheses for mechanisms of fluid retention with ETA antagonism. To do this, we simulated the RADAR clinical trial of atrasentan in patients with type 2 diabetes and CKD and evaluated the ability of the model to predict the observed decreases in haematocrit, urine albumin creatinine ratio (UACR), mean arterial pressure (MAP), and estimated glomerular filtration rate (eGFR). BACKGROUND AND KEY RESULTS: An effect of ETA antagonism on venodilation and increased venous capacitance was found to be the critical mechanism necessary to reproduce the simultaneous decrease in both MAP and haematocrit observed in RADAR. CONCLUSIONS AND IMPACT: These findings indicate that fluid retention with ETA antagonism may not be caused by a direct antidiuretic effect within the kidney but is instead be an adaptive response to venodilation and increased venous capacity, which acutely tends to reduce cardiac filling pressure and cardiac output, and that fluid retention occurs in an attempt to maintain cardiac filling and cardiac output.

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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.

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OBJECTIVE: Ischemic complications account for significant patient morbidity following aneurysmal subarachnoid hemorrhage (aSAH). The Prevention and Treatment of Vasospasm with Clazosentan (REACT) study was designed to assess the safety and efficacy of clazosentan, an endothelin receptor antagonist, in preventing clinical deterioration due to delayed cerebral ischemia (DCI) in patients with aSAH. METHODS: REACT was a prospective, multicenter, randomized, double-blind, phase 3 study. Eligible patients had aSAH secured by surgical clipping or endovascular coiling, and had presented with thick and diffuse clot on admission CT scan. Patients were randomized (1:1 ratio) to 15 mg/hour intravenous clazosentan or placebo within 96 hours of the aSAH for up to 14 days, in addition to standard of care treatment including oral or intravenous nimodipine. The primary efficacy endpoint was the occurrence of clinical deterioration due to DCI up to 14 days after initiation of the study drug. The main secondary endpoint was the occurrence of clinically relevant cerebral infarction at day 16 after study drug initiation. Other secondary endpoints included clinical outcome assessed on the modified Rankin Scale (mRS) and the Glasgow Outcome Scale-Extended (GOSE) at week 12 post-aSAH. Imaging and clinical endpoints were centrally adjudicated. RESULTS: A total of 409 patients were randomized between February 2019 and May 2022 across 74 international sites. Three patients did not start study treatment and were not included in the analysis set. The occurrence of clinical deterioration due to DCI was 15.8% (32/202 patients) in the clazosentan group and 17.2% (35/204 patients) in the placebo group, and the difference was not statistically significant (relative risk reduction [RRR] 7.2%, 95% CI -42.6% to 39.6%, p = 0.734). A nonsignificant RRR of 34.1% (95% CI -21.3% to 64.2%, p = 0.177) was observed in clinically relevant cerebral infarcts treated with clazosentan (7.4%, 15/202) versus placebo (11.3%, 23/204). Rescue therapy was less frequently needed for patients treated with clazosentan compared to placebo (10.4%, 21/202 vs 18.1%, 37/204; RRR 42.6%, 95% CI 5.4%-65.2%). A nonsignificant relative risk increase of 25.4% (95% CI -10.7% to 76.0%, p = 0.198) was reported in the risk of poor GOSE and mRS scores with clazosentan (24.8%, 50/202) versus placebo (20.1%, 41/204) at week 12 post-aSAH. Treatment-emergent adverse events were similar to those reported previously. CONCLUSIONS: Clazosentan administered for up to 14 days at 15 mg/hour had no significant effect on the occurrence of clinical deterioration due to DCI. Clinical trial registration no.: NCT03585270 (ClinicalTrials.gov) EU clinical trial registration no.: 2018-000241-39 (clinicaltrialsregister.eu).

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AIMS: Endothelin-1 (ET-1) is elevated in patients with obesity and adipose tissue of obese mice fed high-fat diet (HFD); however, its contribution to the pathophysiology of obesity is not fully understood. Genetic loss of endothelin type B receptors (ETB) improves insulin sensitivity in rats and leads to increased circulating adiponectin, suggesting that ETB activation on adipocytes may contribute to obesity pathophysiology. We hypothesized that elevated ET-1 in obesity promotes insulin resistance by reducing the secretion of insulin sensitizing adipokines, via ETB receptor. METHODS: Male adipocyte-specific ETB receptor knockout (adETBKO), overexpression (adETBOX), or control littermates were fed either normal diet (NMD) or high-fat diet (HFD) for 8 weeks. RESULTS: RNA-sequencing of epididymal adipose (eWAT) indicated differential expression of over 5500 genes (p < 0.05) in HFD compared to NMD controls, and changes in 1077 of these genes were attenuated in HFD adETBKO mice. KEGG analysis indicated significant increase in metabolic signaling pathway. HFD adETBKO mice had significantly improved glucose and insulin tolerance compared to HFD control. In addition, adETBKO attenuated changes in plasma adiponectin, insulin, and leptin that is observed in HFD versus NMD control mice. Treatment of primary adipocytes with ET-1 caused a reduction in adiponectin production that was attenuated in cells pretreated with an ETB antagonist. CONCLUSION: These data indicate elevated ET-1 in adipose tissue of mice fed HFD inhibits adiponectin production and causes insulin resistance through activation of the ETB receptor on adipocytes.

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Premenopausal women generally exhibit lower blood pressure and a lower prevalence of hypertension than men of the same age, but these differences reverse postmenopause due to estrogen withdrawal. Sexual dimorphism has been described in different components of kidney physiology and pathophysiology, including the renin-angiotensin-aldosterone system, endothelin system, and tubular transporters. This review explores the sex-specific differences in kidney function and blood pressure regulation. Understanding these differences provides insights into potential therapeutic targets for managing hypertension and kidney diseases, considering the patient's sex and hormonal status.

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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.

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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.

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In this study, we present a versatile, scaffold-free approach to create ring-shaped engineered vascular tissue segments using human mesenchymal stem cell-derived smooth muscle cells (hMSC-SMCs) and endothelial cells (ECs). We hypothesized that incorporation of ECs would increase hMSC-SMC differentiation without compromising tissue ring strength or fusion to form tissue tubes. Undifferentiated hMSCs and ECs were co-seeded into custom ring-shaped agarose wells using four different concentrations of ECs: 0%, 10%, 20%, and 30%. Co-seeded EC and hMSC rings were cultured in SMC differentiation medium for a total of 22 days. Tissue rings were then harvested for histology, Western blotting, wire myography, and uniaxial tensile testing to examine their structural and functional properties. Differentiated hMSC tissue rings comprising 20% and 30% ECs exhibited significantly greater SMC contractile protein expression, endothelin-1 (ET-1)-meditated contraction, and force at failure compared with the 0% EC rings. On average, the 0%, 10%, 20%, and 30% EC rings exhibited a contractile force of 0.745 ± 0.117, 0.830 ± 0.358, 1.31 ± 0.353, and 1.67 ± 0.351 mN (mean ± standard deviation [SD]) in response to ET-1, respectively. Additionally, the mean maximum force at failure for the 0%, 10%, 20%, and 30% EC rings was 88.5 ± 36. , 121 ± 59.1, 147 ± 43.1, and 206 ± 0.8 mN (mean ± SD), respectively. Based on these results, 30% EC rings were fused together to form tissue-engineered blood vessels (TEBVs) and compared with 0% EC TEBV controls. The addition of 30% ECs in TEBVs did not affect ring fusion but did result in significantly greater SMC protein expression (calponin and smoothelin). In summary, co-seeding hMSCs with ECs to form tissue rings resulted in greater contraction, strength, and hMSC-SMC differentiation compared with hMSCs alone and indicates a method to create a functional 3D human vascular cell coculture model.

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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.

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Cyclic ADP-ribose (cADPR) has emerged as a calcium-regulating second messenger in smooth muscle cells. CD38 protein possesses ADP-ribosyl cyclase and cADPR hydrolase activities and mediates cADPR synthesis and degradation. We have previously shown that CD38 expression is regulated by estrogen and progesterone in the myometrium. Considering hormonal regulation in gestation, the objective of the present study was to determine the role of CD38/cADPR signaling in the regulation of intracellular calcium upon contractile agonist stimulation using immortalized pregnant human myometrial (PHM1) cells. Western blot, immunofluorescence, and biochemical studies confirmed CD38 expression and the presence of ADP-ribosyl cyclase (2.6 ± 0.1 pmol/mg) and cADPR hydrolase (26.8 ± 6.8 nmoles/mg/h) activities on the PHM1 cell membrane. Oxytocin, PGF2α, and ET-1 elicited [Ca2+]i responses, and 8-Br-cADPR, a cADPR antagonist significantly attenuated agonist-induced [Ca2+]i responses between 20% and 46% in average. The findings suggest that uterine contractile agonists mediate their effects in part through CD38/cADPR signaling to increase [Ca2+]i and presumably uterine contraction. As studies in humans are limited by the availability of myometrium from healthy donors, PHM1 cells form an in vitro model to study human myometrium.

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Pulmonary fibrosis is a severe and progressive lung disease characterized by lung tissue scarring. Transforming growth factor beta 1 (TGFß1) is crucial in causing pulmonary fibrosis by promoting the activation of fibroblasts and their differentiation into myofibroblasts, which are responsible for excessive extracellular matrix deposition. This study aimed to identify genes activated by TGFß1 that promote fibrosis and to understand the regulatory pathway controlling myofibroblast. Endothelin-1 (ET-1) was identified as the top-ranking gene in the fibrosis-related gene set using quantitative PCR array analysis. TGFß1 upregulated EGR1 expression through the ERK1/2 and JNK1/2 MAPK pathways. EGR1 and p-SMAD2 proteins interacted with the ET-1 gene promoter region to regulate TGFß1-induced ET-1 expression in IMR-90 pulmonary fibroblasts. Mice lacking the Egr1 gene showed reduced ET-1 levels in a model of pulmonary fibrosis induced by intratracheal administration of bleomycin. These findings suggest that targeting EGR1 is a promising approach for treating pulmonary fibrosis, especially idiopathic pulmonary fibrosis, by affecting ET-1 expression and profibrotic reactions.