Hemodynamics During Development and Postnatal Life.

A well-developed heart is essential for embryonic survival. There are constant interactions between cardiac tissue motion and blood flow, which determine the heart shape itself. Hemodynamic forces are a powerful stimulus for cardiac growth and differentiation. Therefore, it is particularly interesting to investigate how the blood flows through the heart and how hemodynamics is linked to a particular species and its development, including human. The appropriate patterns and magnitude of hemodynamic stresses are necessary for the proper formation of cardiac structures, and hemodynamic perturbations have been found to cause malformations via identifiable mechanobiological molecular pathways. There are significant differences in cardiac hemodynamics among vertebrate species, which go hand in hand with the presence of specific anatomical structures. However, strong similarities during development suggest a common pattern for cardiac hemodynamics in human adults. In the human fetal heart, hemodynamic abnormalities during gestation are known to progress to congenital heart malformations by birth. In this chapter, we discuss the current state of the knowledge of the prenatal cardiac hemodynamics, as discovered through small and large animal models, as well as from clinical investigations, with parallels gathered from the poikilotherm vertebrates that emulate some hemodynamically significant human congenital heart diseases.

Effects of EGFR-TKI on epidermal melanin unit integrity: Therapeutic implications for hypopigmented skin disorders.

Epidermal melanin unit integrity is crucial for skin homeostasis and pigmentation. Epidermal growth factor (EGF) receptor (EGFR) is a pivotal player in cell growth, wound healing, and maintaining skin homeostasis. However, its influence on skin pigmentation is relatively unexplored. This study investigates the impact and underlying mechanisms of EGFR inhibitors on skin pigmentation. We evaluated EGF and EGFR expression in various skin cells using quantitative real-time PCR, Western blot, and immunofluorescence. EGF and EGFR were predominantly expressed in epidermal keratinocytes, and treatment with the EGFR tyrosine kinase inhibitors (EGFR-TKIs) gefitinib and PD153035 significantly increased stem cell factor (SCF) and endothelin-1 (ET-1) expression in cultured keratinocytes. Enhanced melanocyte migration and proliferation were observed in co-culture, as evidenced by time-lapse live imaging and single-cell tracking assays. Furthermore, topical application of gefitinib to guinea pig dorsal skin induced increased pigmentation and demonstrated efficacy in mitigating rhododendrol-induced leukoderma. Suppression of EGF signaling indirectly enhanced skin pigmentation by upregulating SCF and ET-1 in epidermal keratinocytes. This novel mechanism highlights the pivotal role of EGF signaling in regulating skin pigmentation, and topical EGFR-TKI therapy at an appropriate dose may be a promising approach for depigmentation disorder management.

Evaluation of some nonroutine cardiac biomarkers among adults and children with beta-thalassemia major.

BACKGROUND: Cardiac injury caused by iron overload is the leading cause of mortality and morbidity in patients with beta-thalassemia, owing to frequent blood transfusion, increased iron overload, and blood hemolysis. OBJECTIVE: This research aimed to assess several novel cardiac biomarkers in the blood samples of children and adult patients with beta-thalassemia major (ßTM), along with their respective control groups. These biomarkers included endothelin 1 (ET-1), N-terminal pro-brain natriuretic peptide (NT-proBNP), atrial natriuretic peptide (ANP), growth differentiation factor-15 (GDF-15), and renalase (RNLS). METHODS: This case-control study was done on 46 patients with ßTM (23 children <18 years, and 23 adults ≥18 years) from the Genetic Hematology Center in Thi-Qar province, Iraq, and 42 comparable controls in 2 groups (21 for each group) in the period from February to April 2023. RESULTS: Levels of ET-1, NT-proBNP, ANP, GDF-15, RNLS, and ferritin were higher in the children and adults with ßTM than in the control subjects. CONCLUSION: Elevations of the novel cardiac biomarkers ET-1, NT-proBNP, ANP, GDF-15, and RNLS in the sera of children and adult patients with ßTM when compared with comparable control subjects confirm that the majority of patients with ßTM are at risk of cardiac and cardiovascular complications even when there are no obvious symptoms, especially in children, which gives suitable predictive biomarkers.

Activation of ETAR and ETBR in myocardial tissue characterizes heart failure induced by experimental autoimmune myocarditis.

BACKGROUND: Endothelial dysfunction is characterized by an imbalance between endothelium-derived vasodilatory and vasoconstrictive effects and may play an important role in the development of heart failure. An increasing number of studies have shown that endothelial-derived NO-mediated vasodilation is attenuated in heart failure patients. However, the role of endothelin-1 (ET-1) in heart failure remains controversial due to its different receptors including ET-1 receptor type A (ETAR) and ET-1 receptor type B (ETBR). The aim of this study was to determine whether ET-1 and its receptors are activated and to explore the role of ETAR and ETBR in heart failure induced by myocarditis. METHODS: We constructed an animal model of experimental autoimmune myocarditis (EAM) with porcine cardiac myosin. Twenty rats were randomized to the control group (3 weeks, n = 5), the extended control group (8 weeks, n = 5), the EAM group (3 weeks, n = 5), the extended EAM group (8 weeks, n = 5). HE staining was used to detect myocardial inflammatory infiltration and the myocarditis score, Masson's trichrome staining was used to assess myocardial fibrosis, echocardiography was used to evaluate cardiac function, ELISA was used to detect serum NT-proBNP and ET-1 concentrations, and immunohistochemistry and western blotting were used to detect ETAR and ETBR expression in myocardial tissue of EAM-induced heart failure. Subsequently, a model of myocardial inflammatory injury in vitro was constructed to explore the role of ETAR and ETBR in EAM-induced heart failure. RESULTS: EAM rats tended to reach peak inflammation after 3 weeks of immunization and developed stable chronic heart failure at 8 weeks after immunization. LVEDd and LVEDs were significantly increased in the EAM group compared to the control group at 3 weeks and 8 weeks after immunization while EF and FS were significantly reduced. Serum NT-proBNP concentrations in EAM (both 3 weeks and 8 weeks) were elevated. Therefore, EAM can induce acute and chronic heart failure due to myocardial inflammatory injury. Serum ET-1 concentration and myocardial ETAR and ETBR protein were significantly increased in EAM-induced heart failure in vivo. Consistent with the results of the experiments in vivo, ETAR and ETBR protein expression levels were significantly increased in the myocardial inflammatory injury model in vitro. Moreover, ETAR gene silencing inhibited inflammatory cytokine TNF-α and IL-1ß levels, while ETBR gene silencing improved TNF-α and IL-1ß levels. CONCLUSIONS: ET-1, ETAR, and ETBR were activated in both EAM-induced acute heart failure and chronic heart failure. ETAR may positively regulate EAM-induced heart failure by promoting myocardial inflammatory injury, whereas ETBR negatively regulates EAM-induced heart failure by alleviating myocardial inflammatory injury.

Relationship Between Serum ET-1, HDL-C, and sVCAM-1 and Hearing Loss in Patients with Sudden Deafness.

Vascular causes are most commonly associated with sudden sensorineural hearing loss (SSHL). This study was performed to determine the relationship between serum endothelin-1 (ET-1), high-density lipoprotein cholesterol (HDL-C), soluble vascular cell adhesion molecule-1 (sVCAM-1) levels, and the degree of hearing loss in patients with SSHL. Firstly, 60 SSHL patients were admitted to The First Hospital of Shanxi Medical University. In the same period, 60 healthy subjects matching the age and gender of SSHL patients were selected as the control group. Then, serum levels of ET-1, HDL-C, and sVCAM-1 were measured by enzyme-linked immunosorbent assay (ELISA). Next, the relationship between serum levels of ET-1, HDL-C, and sVCAM-1 with clinicopathological factors and their diagnostic and prognostic values were analyzed and evaluated. Serum ET-1 and sVCAM-1 were increased, and HDL-C was decreased in patients with SSHL. Serum ET-1 and sVCAM-1 were higher and HDL-C was lower in patients aged ≥ 45 years, or severe hearing loss patients (P < 0.05). ROC analysis determined that ET-1 (AUC = 0.839), HDL-C (AUC = 0.830), and sVCAM-1 (AUC = 0.865) had excellent diagnostic values. In addition, patients with low levels of ET-1 and sVCAM-1 and high levels of HDL-C had better hearing prognosis (P < 0.05). Abnormal serum ET-1, HDL-C, and sVCAM-1 in patients with SSHL are closely related to age, and degree of hearing loss, and perform diagnostic and prognostic values.

Luteolin prevents TNF-α-induced NF-κB activation and ROS production in cultured human placental explants and endothelial cells.

INTRODUCTION: Preeclampsia (PE) is a serious hypertensive pregnancy disorder and a leading cause of maternal and perinatal morbidity and mortality. Despite the prevalence and complications, there are no approved therapeutics to relieve PE symptoms. Inflammation, oxidative stress, and angiogenic imbalance have been shown to contribute to the PE pathophysiology, though there is a lack of understanding in how best to target these pathways in PE. We recently demonstrated that the bioflavonoid luteolin is a potent inhibitor of the anti-angiogenic and pro-hypertensive soluble fms-like tyrosine kinase 1 (sFlt-1), and here we aimed to determine if luteolin was also capable of reducing inflammation and oxidative stress pathways. METHODS: Tumor necrosis factor (TNF)-α, which is upregulated in PE, was utilized to stimulate these pathways in human placental explants and endothelial cells. Endothelin-1 (ET-1) and interleukin (IL)-6 in the media from explants and cells were measured via ELISA, and NF-κB localization and reactive oxygen species were detected via fluorescence microscopy. RESULTS: Pretreatment with luteolin demonstrated significant reductions in NF-κB activation, reactive oxygen species, superoxide, and IL-6 and ET-1 expression in endothelial cells. We also saw a significant reduction in phosphorylation of NF-κB in human placental explants. DISCUSSION: These data demonstrate that luteolin inhibits pathways implicated in the development of PE and should be explored further for its potential as a PE therapeutic.

Role of endothelin ETA receptors in the hypertension induced by the VEGFR-2 kinase inhibitors axitinib and lenvatinib in conscious freely-moving rats.

Receptor tyrosine kinase inhibitors (RTKIs) suppress tumour growth by targeting vascular endothelial growth factor receptor 2 (VEGFR-2) which is an important mediator of angiogenesis. Here, we demonstrate that two potent RTKIs, axitinib and lenvatinib, are associated with hypertensive side effects. Doppler flowmetry was used to evaluate regional haemodynamic profiles of axitinib and lenvatinib. Male Sprague Dawley rats (350-500 g) were instrumented with Doppler flow probes (renal and mesenteric arteries and descending abdominal aorta) and catheters (jugular vein and distal abdominal aorta, via the caudal artery). Rats were dosed daily with axitinib (3 or 6 mg.kg-1) or lenvatinib (1 or 3 mg.kg-1) and regional haemodynamics were recorded over a maximum of 4 days. Both RTKIs caused significant (p < 0.05) increases in mean arterial pressure (MAP), which was accompanied by significant (p < 0.05) vasoconstriction in both the mesenteric and hindquarters vascular beds. To gain insight into the involvement of endothelin-1 (ET-1) in RTKI-mediated hypertension, we also monitored heart rate (HR) and MAP in response to axitinib or lenvatinib in animals treated with the ETA receptor selective antagonist sitaxentan (5 mg.kg-1) or the mixed ETA/ETB receptor antagonist bosentan (15 mg.kg-1) over two days. Co-treatment with bosentan or sitaxentan markedly reduced the MAP effects mediated by both RTKIs (p < 0.05). Bosentan, but not sitaxentan, also attenuated ET-1 mediated increases in HR. These data suggest that selective antagonists of ETA receptors may be appropriate to alleviate the hypertensive effects of axitinib and lenvatinib.

sST2 and Big ET-1 as Alternatives of Multi-Biomarkers Strategies for Prognosis Evaluation in Patients Hospitalized with Heart Failure.

Objective: To identify biomarkers with independent prognostic value and investigate the prognostic value of multiple biomarkers in combination in patients hospitalized with heart failure. Methods: A total of 884 consecutive patients hospitalized with heart failure from 2015 to 2017 were enrolled. Twelve biomarkers were measured on admission, and the relationships between biomarkers and outcomes were assessed. Results: During the median follow-up of 913 days, 291 patients (32.9%) suffered from primary endpoint events. Soluble suppression of tumorigenicity-2 (sST2) (per log [unit] increase, adjusted HR [95% CI]: 1.39 [1.13,1.72], P = 0.002) and big endothelin-1 (big ET-1) (per log [unit] increase, adjusted HR [95% CI]: 1.56 [1.23,1.97], P < 0.001) remained independent predictors of primary endpoint event after adjusting for other predictors including N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT). Both sST2 (C-statistic: 0.810 vs 0.801, P = 0.005, and 0.832 vs 0.826, P = 0.024, respectively) and big ET-1 (C-statistic: 0.829 vs 0.801, P = 0.001, and 0.843 vs 0.826, P < 0.001, respectively) significantly improved the predictive value for primary endpoint event at 1 year and 3 years. However, only big ET-1 (C-statistic: 0.852 vs 0.846, P = 0.014) significantly improved the predictive value at 3 months when added to clinical predictors and known biomarkers. According to the number of elevated biomarkers (including NT-proBNP, hs-cTnT, sST2, and big ET-1), patients with three or more elevated biomarkers had a higher risk of primary endpoint event compared to those with two elevated biomarkers (P = 0.001), as well as in patients with two elevated biomarkers compared to those with one elevated biomarker (P = 0.004). However, the risk of primary endpoint event was comparable between patients with one elevated biomarker and those with no elevated biomarker (P = 0.582). Conclusion: Multiple biomarkers in combination could provide a better prognostic value than a single biomarker. sST2 and big ET-1 could act as alternatives of multi-biomarkers strategies for prognosis evaluation beyond NT-proBNP and hs-cTnT in patients hospitalized with heart failure.

Circulatory Maternal Endothelin 1 and Matrix Metalloproteinase-9 Gene Expression in PREECLAMPSIA: A Study in Western Uttar Pradesh, India.

Introduction: Preeclampsia (PE) is a multiorgan disease of pregnant women. The main pathophysiology of PE is a trophoblastic invasion into maternal circulation leading to alterations in circulatory levels of matrix metalloproteinases (MMPs), inflammatory markers, and endothelin 1(ET1) levels. Therefore, the present study has explored the role of MMP-9 and ET1 and their association in PE. The advantage of the study is to provide insight into the pathology of PE. These markers may help in the early diagnosis and prognosis of PE. Objective: To investigate MMP-9 gene expression, ET1 level in PE cases and their correlation with blood pressure (BP), gestational age, weight, and height. Methods: The study design was a case-control observational study, which included 70 subjects in each case (PE) and controls (normal pregnant women (NPW)). Whole blood (250 ul) was utilized for RNA extraction (Trizol method) and synthesized cDNA as per manufacturer protocol. MMP-9 gene expression was analyzed by real-time PCR. Serum was utilized for ET1 estimation by sandwich ELISA. Results: The ET1 levels and MMP-9 gene expression were significantly increased in preeclamptic women as compared to controls. There was no significant correlation between MMP-9 gene expression and serum ET1 levels. However, a significant moderate association between systolic BP and diastolic BP with ET1 levels and MMP9 gene expression was seen in both PE and NPW. Conclusion: A significantly increased circulatory concentration of ET1 and MMP-9 gene expression in PE might be used as an early diagnostic as well as a prognostic marker of PE.

BAO-Ag-NPs as Promising Suppressor of ET-1/ICAM-1/VCAM-1 Signaling Pathway in ISO-induced AMI in Rats.

OBJECTIVES: Acute myocardial infarction (AMI) is the most prevalent cause of myocardial fibrosis and the leading cause of mortality from cardiovascular disease. The goal of this work was to synthesize Balanites aegyptiaca oil-silver nanoparticles (BAO-Ag-NPs) and evaluate their cardioprotective effect against ISO-induced myocardial infarction in rats, as well as their mechanism. METHODS: BAO was isolated, and the unsaturated fatty acids were estimated. BAO-Ag-NPs was prepared, LD50 was calculated to evaluate its cardioprotective activity against ISO (85 mg/kg)- induced AMI. Different doses of BAO-Ag-NPs (1/50 LD50; 46.6 mg/kg.b.w and 1/20 LD50; 116.5 mg) were received to the rats. RESULTS: The total fatty acids and unsaturated fatty acids generated by BAO were 909.63 and 653.47 mg/100 g oil, respectively. Oleic acid methyl ester, 9-Octadecenoic acid methyl ester, and 9, 12-Octadecadienoic acid methyl ester were the predominant ingredients, with concentrations of 107.6, 243.42, and 256.77 mg/100 g oil, respectively. According to TEM and DLS examinations, BAO-Ag-NPs have a size of 38.20±2.5 nm and a negative zeta potential of -19.82 ± 0.30 mV, respectively. The LD50 of synthesized BAO-Ag-NPs is 2330 mg. On the other hand, BAO-Ag-NPs reduce myocardial necrosis by lowering increased BNP, cTnI, CK-MB, TC, TG, MDA, MMP2, TGF-ß1, PGE2, and IL-6 levels. Furthermore, BAO-Ag-NPs inhibit the expression of ET-1, ICAM-1, and VCAM-1 genes. BAO-Ag-NPs given to ISO-treated rats enhance HDL-C, CAT, and GSH levels when compared to the ISO-treated group of rats. Histopathological findings suggested that BAO-Ag-NPs enhance cardiac function by increasing posterior wall thickness in heart tissues. CONCLUSION: BAO-Ag-NPs protect against AMI in vivo by regulating inflammation, excessive autophagy, and oxidative stress, as well as lowering apoptosis via suppression of the ET-1, ICAM-1, and VCAM-1 signaling pathways.

Environmental enrichment enhanced neurogenesis and behavioral recovery after stroke in aged rats.

BACKGROUND AND PURPOSE: Age is identified as a significant prognostic factor for poorer outcome after stroke. However, environmental enrichment (EE) has been reported to promote functional recovery after ischemic stroke. The purpose of this study was to investigate whether environmental enrichment was beneficial to ischemic stroke in aged rats. METHODS: Aged rats were randomly assigned as control rats, rats subjected to cerebral ischemia, and rats with cerebral ischemia treated with EE for 30 days. Focal cortical ischemia was induced by intracranial injection of endothelin-1 (ET-1). EE housing began one day after focal ischemia and was maintained for the whole experimental period. We used immunofluorescence staining to analyze the neurogenesis in the subventricular zone (SVZ) and TdT-mediated dUTP-biotin nick-end labeling (TUNEL) assay to evaluate apoptosis. The expression of neuronal nuclei, glial fibrillary acidic protein (GFAP) and Iba-1 around the infarcted area were also measured by double immunohistochemistry. RESULTS: EE enhanced the proliferation of newborn neurons in the SVZ, as well as increased the long-term survival of newborn neurons. EE also exerted effects on inflammation after stroke. Furthermore, EE suppressed apoptosis and improved the motor functions after stroke in the aged rats. CONCLUSIONS: EE improved post-stroke recovery on the basis of enhancing neurogenesis in aged rats.

Comparison of ET-1 and eNOS expressions in yak testes at different developmental stages.

Yak has strong adaptability to plateau hypoxia environment. However, the endothelin-1 (ET-1) and endothelial nitric oxide synthase (eNOS) are important regulators in blood oxygen transportation. Yak testes: newborn (3 days), young (1 years), adult (4 years) and old (9 years) were collected for microscopic analyses using haematoxylin and eosin staining (H&E), immunohistochemistry and immunofluorescence, as well as Western blot to compare the expression of ET-1 and eNOS. Furthermore, the levels of ET-1 mRNA and eNOS mRNA was detected by real-time quantitative polymerase chain reaction (RT-qPCR). The results showed that ET-1 mRNA and eNOS mRNA in old yaks were higher than other developmental stages (p < .01). And the levels of ET-1 and eNOS protein increased with age. Immunohistochemistry and immunofluorescence showed that ET-1 and eNOS were mainly localized in gonocytes and spermatogenic membrane of newborn yaks. These two factors were expressed in both Leydig cells of young yaks and endothelial cells of adult yaks. In old yaks, ET-1 was mainly expressed in Sertoli cells, while eNOS was obviously positive in capillaries and Leydig cells. Therefore, the positive results of ET-1 and eNOS in gonocyte and spermatogenic basement were closely related to the development of testes. The expression of Leydig and Sertoli cells indicated that they played an important role in testes function. The expression in endothelial cells or interstitial capillaries, suggesting that they are involved in the regulation of microcirculation in yak testes. This study could provide clues for further revealing the regulation of yak testicular blood vessels in alpine cold and hypoxic environments.

E-Selectin, ICAM-1, and ET-1 Biomarkers Address the Concern of the Challenging Diagnosis of Interstitial Lung Disease in Patients with Autoimmune Diseases.

Interstitial lung disease (ILD) constitutes the most critical comorbidity in autoimmune diseases (ADs) and its early diagnosis remains a challenge for clinicians. Accordingly, we evaluated whether E-selectin, ICAM-1, and ET-1, key molecules in endothelial damage, could be useful biomarkers for the detection of AD-ILD+. We recruited patients with rheumatoid arthritis (RA)-ILD+ (n = 21) and systemic sclerosis (SSc)-ILD+ (n = 21). We included comparison groups of patients: RA-ILD- (n = 25), SSc-ILD- (n = 20), and idiopathic pulmonary fibrosis (IPF) (n = 21). Serum levels of these proteins were determined by ELISA. E-selectin, ICAM-1, and ET-1 serum levels were increased in RA-ILD+ and IPF patients in comparison to RA-ILD- patients. Additionally, SSc-ILD+ and IPF patients exhibited higher ICAM-1 levels than those with SSc-ILD-. The ability of E-selectin, ICAM-1, and ET-1 to discriminate RA-ILD+ from RA-ILD- patients, and ICAM-1 to distinguish SSc-ILD+ from SSc-ILD- patients was confirmed using ROC curve analysis. Furthermore, elevated levels of ET-1 and E-selectin correlated with lung function decline in RA-ILD+ and SSc-ILD+ patients, respectively. In conclusion, our findings support the relevant role of E-selectin, ICAM-1, and ET-1 in RA-ILD+ patients as well as of ICAM-1 in SSc-ILD+ patients, constituting potential screening blood biomarkers of ILD in AD. Moreover, this study suggests ET-1 and E-selectin as possible indicators of worsening lung function in RA-ILD+ and SSc-ILD+ patients, respectively.

Tumor Necrosis Factor (TNF) α, Endothelin (ET) 1 and α1-Acid Glycoprotein (AGP) as Potential Urine and Serum Markers of Metabolic Complications in Psoriasis?

INTRODUCTION: Psoriasis, one of the most frequent dermatoses, strongly associated with metabolic disorders which increase patients' comorbidity and mortality. Hence, it is essential to look for markers of such complications. Our aim was to assess the clinical utility of urinary tumor necrosis factor alpha (TNFα), endothelin 1 (ET-1) and α1-acid glycoprotein (α1AGP) as well as their serum concentrations as markers of metabolic complications in psoriatics, and to examine the relations of these markers to clinical and demographic parameters. METHODS: The study involved 60 patients with plaque psoriasis and 30 volunteers without skin diseases (the control group). Serum and urinary concentrations of TNFα, ET-1 and α1AGP were measured by ELISA. Psoriasis severity was assessed using the psoriasis activity and severity index (PASI). Routine laboratory investigations were additionally performed. RESULTS: All serum markers were significantly higher in the patients compared to the controls. TNFα was undetectable in the urine in half of the patients. The urinary ET-1/creatinine concentration ratio was significantly lower in the psoriatics than the controls, whereas the absolute urinary α1AGP was significantly higher and the α1AGP/creatinine ratio was insignificantly different. There was no correlation between serum or urinary markers and PASI. All serum markers were higher in patients with psoriasis lasting less than 15 years. CONCLUSIONS: Serum TNFα, ET-1 and α1AGP seem to be useful biomarkers of metabolic syndrome in psoriatics. ET-1 could perhaps become a urinary marker of metabolic disorders in psoriatics, but further studies are required to confirm that a decreased ET-1 concentration in urine is a reliable predictive tool. Increased urinary α1AGP also requires more in-depth research as a potential marker. TNFα urine assessment does not seem to be useful for screening for metabolic disorders in psoriatics. Serum or urinary TNFα, ET-1 and α1AGP do not seem to be associated with psoriasis severity or duration.

Drug repurposing-a promising approach for patients with angina but non-obstructive coronary artery disease (ANOCA).

In today's era of individualized precision medicine drug repurposing represents a promising approach to offer patients fast access to novel treatments. Apart from drug repurposing in cancer treatments, cardiovascular pharmacology is another attractive field for this approach. Patients with angina pectoris without obstructive coronary artery disease (ANOCA) report refractory angina despite standard medications in up to 40% of cases. Drug repurposing also appears to be an auspicious option for this indication. From a pathophysiological point of view ANOCA patients frequently suffer from vasomotor disorders such as coronary spasm and/or impaired microvascular vasodilatation. Consequently, we carefully screened the literature and identified two potential therapeutic targets: the blockade of the endothelin-1 (ET-1) receptor and the stimulation of soluble guanylate cyclase (sGC). Genetically increased endothelin expression results in elevated levels of ET-1, justifying ET-1 receptor blockers as drug candidates to treat coronary spasm. sGC stimulators may be beneficial as they stimulate the NO-sGC-cGMP pathway leading to GMP-mediated vasodilatation.

Alterations in pulmonary vasomotor modulators post aerobic exercise training in non-alcoholic fatty liver disease.

This study investigated the impact of exercise training on major pulmonary vasomotor mediators and receptors including endothelial nitric oxide synthase (eNOS) inducible NOS (iNOS), endothelin-1 (ET-1), ET-1 receptors A (ETA) and-B (ETB) in high-fat-high-carbohydrate (HFHC) induced non-alcoholic fatty liver disease (NAFLD). NAFLD increased iNOS, ET-1 and ETA (p < 0.05), but not ETB (p > 0.05). Exercise attenuated iNOS, ET-1 and ETA (p < 0.05)., but not ETB (p > 0.05) and eNOS (p > 0.05). Exercise training is beneficial for pulmonary vasculature in NAFLD.

Endothelin-1 induces connective tissue growth factor expression in human lung fibroblasts by disrupting HDAC2/Sin3A/MeCP2 corepressor complex.

BACKGROUND: Reduction of histone deacetylase (HDAC) 2 expression and activity may contribute to amplified inflammation in patients with severe asthma. Connective tissue growth factor (CTGF) is a key mediator of airway fibrosis in severe asthma. However, the role of the HDAC2/Sin3A/methyl-CpG-binding protein (MeCP) 2 corepressor complex in the regulation of CTGF expression in lung fibroblasts remains unclear. METHODS: The role of the HDAC2/Sin3A/MeCP2 corepressor complex in endothelin (ET)-1-stimulated CTGF production in human lung fibroblasts (WI-38) was investigated. We also evaluated the expression of HDAC2, Sin3A and MeCP2 in the lung of ovalbumin-induced airway fibrosis model. RESULTS: HDAC2 suppressed ET-1-induced CTGF expression in WI-38 cells. ET-1 treatment reduced HDAC2 activity and increased H3 acetylation in a time-dependent manner. Furthermore, overexpression of HDAC2 inhibited ET-1-induced H3 acetylation. Inhibition of c-Jun N-terminal kinase, extracellular signal-regulated kinase, or p38 attenuated ET-1-induced H3 acetylation by suppressing HDAC2 phosphorylation and reducing HDAC2 activity. Overexpression of both Sin3A and MeCP2 attenuated ET-1-induced CTGF expression and H3 acetylation. ET-1 induced the disruption of the HDAC2/Sin3A/MeCP2 corepressor complex and then prompted the dissociation of HDAC2, Sin3A, and MeCP2 from the CTGF promoter region. Overexpression of HDAC2, Sin3A, or MeCP2 attenuated ET-1-stimulated AP-1-luciferase activity. Moreover, Sin3A- or MeCP2-suppressed ET-1-induced H3 acetylation and AP-1-luciferase activity were reversed by transfection of HDAC2 siRNA. In an ovalbumin-induced airway fibrosis model, the protein levels of HDAC2 and Sin3A were lower than in the control group; however, no significant difference in MeCP2 expression was observed. The ratio of phospho-HDAC2/HDAC2 and H3 acetylation in the lung tissue were higher in this model than in the control group. Overall, without stimulation, the HDAC2/Sin3A/MeCP2 corepressor complex inhibits CTGF expression by regulating H3 deacetylation in the CTGF promoter region in human lung fibroblasts. With ET-1 stimulation, the HDAC2/Sin3A/MeCP2 corepressor complex is disrupted and dissociated from the CTGF promoter region; this is followed by AP-1 activation and the eventual initiation of CTGF production. CONCLUSIONS: The HDAC2/Sin3A/MeCP2 corepressor complex is an endogenous inhibitor of CTGF in lung fibroblasts. Additionally, HDAC2 and Sin3A may be of greater importance than MeCP2 in the pathogenesis of airway fibrosis.

Mechanism Underlying Triple VEGFR Inhibitor Tivozanib-Induced Hypertension in Mice Model.

Tivozanib is a triple vascular endothelial growth factor receptor inhibitor, recently approved for the treatment of refractory advanced renal cell carcinoma. Clinical studies showed that around 46% of patients who received tivozanib suffer from hypertension in all grades. Thus, the present study was conducted to identify the role of angiotensin-II (AngII) in the mechanism underlying tivozanib-induced vascular toxicity and hypertension. C57BL/6 male mice received tivozanib (1 mg/kg) with or without losartan (10 or 30 mg/kg) for 3 weeks. Blood pressure was recorded every 3 days, and proteinuria was measured every week. On day 21, all mice were euthanized, and samples were harvested for further analysis. Tivozanib elevated blood pressure until systolic blood pressure reached 163 ± 6.6 mmHg on day 21 of treatment with low urination and high proteinuria. AngII and its receptors, endothelin-1, and oxidative stress markers were significantly increased. While nitric oxide (NO) levels were reduced in plasma and aortic tissues. AngII type 1 receptor blockade by losartan prevented these consequences caused by tivozanib and kept blood pressure within normal range. The results showed that AngII and ET-1 might be potential targets in the clinical studies and management of hypertension induced by tivozanib.

GARP on hepatic stellate cells is essential for the development of liver fibrosis.

BACKGROUND & AIMS: Glycoprotein A repetitions predominant (GARP) is a membrane protein that functions as a latent TGF-ß docking molecule. While the immune regulatory properties of GARP on blood cells have been studied, the function of GARP on tissue stromal cells remains unclear. Here, we investigate the role of GARP expressed on hepatic stellate cells (HSCs) in the development of liver fibrosis. METHODS: The function of GARP on HSCs was explored in toxin-induced and metabolic liver fibrosis models, using conditional GARP-deficient mice or a newly generated inducible system for HSC-specific gene ablation. Primary mouse and human HSCs were isolated to evaluate the contribution of GARP to the activation of latent TGF-ß. Moreover, cell contraction of HSCs in the context of TGF-ß activation was tested in a GARP-dependent fashion. RESULTS: Mice lacking GARP in HSCs were protected from developing liver fibrosis. Therapeutically deleting GARP on HSCs alleviated the fibrotic process in established disease. Furthermore, natural killer T cells exacerbated hepatic fibrosis by inducing GARP expression on HSCs through IL-4 production. Mechanistically, GARP facilitated fibrogenesis by activating TGF-ß and enhancing endothelin-1-mediated HSC contraction. Functional GARP was expressed on human HSCs and significantly upregulated in the livers of patients with fibrosis. Lastly, deletion of GARP on HSCs did not augment inflammation or liver damage. CONCLUSIONS: GARP expressed on HSCs drives the development of liver fibrosis via cell contraction-mediated activation of latent TGF-ß. Considering that systemic blockade of TGF-ß has major side effects, we highlight a therapeutic niche provided by GARP and surface-mediated TGF-ß activation. Thus, our findings suggest an important role of GARP on HSCs as a promising target for the treatment of liver fibrosis. IMPACT AND IMPLICATIONS: Liver fibrosis represents a substantial and increasing public health burden globally, for which specific treatments are not available. Glycoprotein A repetitions predominant (GARP) is a membrane protein that functions as a latent TGF-ß docking molecule. Here, we show that GARP expressed on hepatic stellate cells drives the development of liver fibrosis. Our findings suggest GARP as a novel target for the treatment of fibrotic disease.

BQ788 reveals glial ETB receptor modulation of neuronal cholinergic and nitrergic pathways to inhibit intestinal motility: Linked to postoperative ileus.

BACKGROUND AND PURPOSE: ET-1 signalling modulates intestinal motility and inflammation, but the role of ET-1/ETB receptor signalling is poorly understood. Enteric glia modulate normal motility and inflammation. We investigated whether glial ETB signalling regulates neural-motor pathways of intestinal motility and inflammation. EXPERIMENTAL APPROACH: We studied ETB signalling using: ETB drugs (ET-1, SaTX, BQ788), activity-dependent stimulation of neurons (high K+ -depolarization, EFS), gliotoxins, Tg (Ednrb-EGFP)EP59Gsat/Mmucd mice, cell-specific mRNA in Sox10CreERT2 ;Rpl22-HAflx or ChATCre ;Rpl22-HAflx mice, Sox10CreERT2 ::GCaMP5g-tdT, Wnt1Cre2 ::GCaMP5g-tdT mice, muscle tension recordings, fluid-induced peristalsis, ET-1 expression, qPCR, western blots, 3-D LSM-immunofluorescence co-labelling studies in LMMP-CM and a postoperative ileus (POI) model of intestinal inflammation. KEY RESULTS: In the muscularis externa ETB receptor is expressed exclusively in glia. ET-1 is expressed in RiboTag (ChAT)-neurons, isolated ganglia and intra-ganglionic varicose-nerve fibres co-labelled with peripherin or SP. ET-1 release provides activity-dependent glial ETB receptor modulation of Ca2+ waves in neural evoked glial responses. BQ788 reveals amplification of glial and neuronal Ca2+ responses and excitatory cholinergic contractions, sensitive to L-NAME. Gliotoxins disrupt SaTX-induced glial-Ca2+ waves and prevent BQ788 amplification of contractions. The ETB receptor is linked to inhibition of contractions and peristalsis. Inflammation causes glial ETB up-regulation, SaTX-hypersensitivity and glial amplification of ETB signalling. In vivo BQ788 (i.p., 1 mg·kg-1 ) attenuates intestinal inflammation in POI. CONCLUSION AND IMPLICATIONS: Enteric glial ET-1/ETB signalling provides dual modulation of neural-motor circuits to inhibit motility. It inhibits excitatory cholinergic and stimulates inhibitory nitrergic motor pathways. Amplification of glial ETB receptors is linked to muscularis externa inflammation and possibly pathogenic mechanisms of POI.