Increased Expression of Endothelin Receptors in Human Cirrhosis—— Relationship with Splanchnic Hemodynamics

The purpose of the present study was to assess the correlation that likely exists among increased portal pressure (P p), portal blood flow quantity (Q p) and ET A and ET B receptor mRNA expression in human cirrhosis. In situ hybridization and reverse transcription polymerase chain reactions (RT PCR) were performed to determine the expression of ET A and ET B receptor mRNA in liver tissues from traumatic subjects ( n =10) and cirrhotic patients ( n =15) in whom hepatic hemodynamic values were measured. The expression of the two transcripts was significantly higher in liver samples of cirrhotic patients than in those obtained from traumatic subjects. It has shown that ET A receptor mRNA predominantly located in hepatic stellate cells (HSCs) and vascular smooth muscle cells of intrahepatic arteries and portal veins, ET B receptor mRNA in HSCs, sinusoidal endothelial cells and Kuppfer cells. There was a highly significant direct relationship between ET A and ET B receptor mRNA and P p and Q p in cirrhotic patients. It suggests that liver paracrine endothelin system may be overactivated in human cirrhosis accompanied with increased expression of ET A and ET B receptor mRNA which may play an important role in the pathogenesis and maintenance of splanchnic hyperdynamics.

Correlation between Pulmonary Endothelin Receptors and Alveolar-arterial Oxygen Gradient in Rats with Hepatopulmonary Syndrome

The correlation between pulmonary endothelin receptors and alveolar-arterial oxygen gradient （A aDO2） in rats with hepatopulmonary syndrome was investigated. Animals were divided into 2 groups： Sham operated （Sham） group and common bile duct ligation （CBDL） group. Arterial blood gas was evaluated by a blood gas analyzer. The concentrations of ET-1 in blood and lung tissue sample were evaluated by radioimmunoassay. The distribution and expression of two kinds of subtype receptor of ET-1, ETRA and ETRB were examined by in situ hybridization. The results showed that the level of A aDO2, was higher in CBDI. group than that in Sham group （P〈0.05）. The levels of plasma and pulmonary ET-1 in CBDL group were both higher than in Sham group （P〈0.05 ）. There was no significant difference in average A of ETRA between two groups by imaging analysis （0.21±0.06 vs 0.22±0.08, P〉0.05）, while that of ETRB was higher in CBDI. group than in Sham group （0.58±0.16 vs 0.28±0.07, P〈0.05）. The expression of ETRBinlung was positively correlated with A aDO2（P〈0.05）. It was concluded that the widened A-aDO2 may be related with enhancement of the expression of ETRB in lung.

Externalization and internalization of cardiac endothelin receptors during different phases of sepsis in rat

Objective To study the redistribution of ET1 receptors in two subcellular organelles, the sarcolemmal membrane and the light vesicle, of rat heart during the progress of septic shock Methods Male Sprague Dawley rats weighing from 270 to 320?g were randomly divided into three groups: control, early sepsis, and late sepsis Each group included six rats Sepsis was induced by cecal ligation and puncture (CLP) Control rats were sham operated After operation for 9 hours or 18 hours, animals of the three groups were anesthetized with sodium pentobarbital (60?mg/kg IP) and the hearts were removed for preparation of sarcolemma and light vesicle Hemodynamic parameters were determined with polygraph via femoral artery and intraventricular cannula ET1 receptor was assayed by [ 125 I] ET1 binding Results Heart rate, cardiac output and left ventricular +dp/dt max undergo biphasic changes: an increase in early phase of sepsis (9?h after CLP) followed by a decrease in late phase of sepsis (18?h after CLP) Mean arterial blood pressure and left ventricular dp/dt max remained relatively unaltered during early phase of sepsis but was decreased during late phase of sepsis Although septic rat heart exhibited biphasic cardiodynamic changes, myocardial function showed signs of progressive deterioration during the development of sepsis, as indicated by a progressive elevation of LVEDP [ 125 I] ET1 bindings to cardiac membranes exhibited a saturable process with a single component binding characteristic for all three experimental groups In sarcolemmal membrane fraction, the maximum binding capacity (B max ) calculated from scatchard plot was increased 30% ( P <0 01) during early phase of sepsis but decreased 24% ( P <0 01) during late phase of sepsis The affinity [the reciprocal of the dissociation contant (Kd)] for [ 125 I] ET1 binding in sarcolemmal membranes remained unaffected during early and late phases of sepsis In light vesicle fraction, the B max for [ 125 I] ET1 binding was decreased by 19% ( P <0 05) during early phase of sepsis but increased by 38% ( P <0 01) during late phase of sepsis The affinity for [ 125 I] ET1 binding in light vesicles was unaltered in early and late phases of sepsis It should be mentioned that the sum of Bmax of sarcolemmal and light vesicle fractions was increased by 25% ( P <0 01) during early phase of sepsis but was decreased by 17% ( P <0 01) during late phase of sepsis Conclusions These data indicated that a biphasic intracellular redistribution of ET1 receptor in the heart might contribute to the development of the initial hyperdynamic and subsequent hypodynamic state during sepsis

Endothelin receptor antagonists for the treatment of diabetic nephropathy:A meta-analysis and systematic review

BACKGROUND Diabetic nephropathy(DN)is the main cause of chronic kidney disease and endstage renal disease worldwide.Although available clinical trials have shown that endothelin receptor(ER)antagonists may be a novel and beneficial drug for DN,no consistent conclusions regarding their sufficient effectiveness and safety for patients with DN have been presented.AIM To assess the effectiveness and safety of ER antagonists among patients with DN.METHODS The EMBASE,PubMed,MEDLINE,Cochrane,and ClinicalTrials.gov databases were searched without any language restrictions.Relative risks with 95%confidence intervals(CIs)for dichotomous data and mean differences or standardized mean difference with 95%CIs for continuous data were calculated using Review Manager 5.3 software.Publication bias was assessed using Egger’s test with Stata/SE software.RESULTS We enrolled seven studies with six data sets and 5271 participants.The ER antagonists group showed a significantly greater reduction in albuminuria and more patients with 40%reduction in urinary albumin-to-creatinine ratio than the control group(P<0.0001 and P=0.02,respectively).Subgroup analysis for reductions in estimated glomerular filtration rate(eGFR)showed that for the middle-dosage subgroup,the ER antagonists group exhibited lower eGFR reduction than the control group(P<0.00001;mean difference,0.7095%CI:0.66,0.74).Moreover,significant reductions in systolic and diastolic blood pressure were observed in the invention group.CONCLUSION ER blockades combined with angiotensin converting enzyme inhibitor/angiotensin II type 1 receptor blockers may be an effective treatment to lower blood pressure and reduce proteinuria in DN with declined eGFR.However,attention should be given to adverse events,including cardiac failure,anemia,and hypoglycemia,as well as serious adverse events.

Correlation of calcitonin gene-related peptide and endothelin receptor A with subarachnoid hemorrhage

Numerous studies have demonstrated that endothelin-1 combines with endothelin receptor A, resulting in intense vasoconstriction. Although calcitonin gene-related peptide （CGRP） suppresses endothelin-1, CGRP and endothelin receptor A exhibit direct biological effects on brain tissue. The present study analyzed CGRP and endothelin receptor A expression following subarachnoid hemorrhage in rabbits using immunohistochemistry. CGRP expression was significant at 5 days after model establishment, and endothelin receptor A expression was significant at 3 days after model induction. The perimeter of the basilar artery was measured to determine the amount of cerebral vasospasm. Analytical results revealed a significantly shortened basilar artery perimeter following subarachnoid hemorrhage. Changes in the basilar artery perimeter were negatively associated with endothelin receptor A expression, but positively correlated with CGRP expression in vessels. These results suggest that following subarachnoid hemorrhage, CGRP and endothelin receptor A expressions dynamically changed in brain vessels and tissues, although these changes were not synchronous. Changes in endothelin receptor A expression exhibited a significant effect on the occurrence and development of delayed cerebral vasospasm and delayed neuronal death, while CGRP relaxed vessels and protected nerves.

The Expression of Endothelin Receptor B in Melanoma Cells A375 and Sk-mel-1 and the Proliferative Effects of Endothelin 3 on A375 Cells

In order to investigate the expression of endothelin receptor B （ETR-B） in human malignant melanoma （MM） cells A375 and SK-mel-1 and the proliferative effects of endothelin 3 （ET3） on A375 cells, RT-PCR was applied to detect the expression of ETR-B gene in human MM cells A375 and SK-mel-1. MTT method was used to evaluate the growth enhancing effects of ET3 on A375 cell line in vitro. The results showed that ETR-B gene was expressed in both MM A375 and SK-mel-1 cells. ET3 had stronger ability to enhance the proliferation of A375 cells in vitro in a concentration-dependent manner. It was suggested that ET3/ETR-B might play an important proliferative role in MM.

Synthesis and Crystal Structure of an Endothelin Receptor Antagonist Ambrisentan

The title compound was synthesized and its crystal structure was determined by single-crystal X-ray diffraction. The crystal is of orthorhombic system （C22H22N2O4, Mr = 378.42）, space group P2121 with a = 6.8786（12）, b = 14.259（2）, c = 19.712（3） A, V= 1933.5（6） A3, Z = 4, Dc = 1.300 g/cm3, f（000） = 800, μ= 0.090 mm-1, the final R = 0.0324 and wR = 0.0775 for 2410 observed reflections （I 〉 2σ（I））. The structure, especially the absolute configuration, of the title compound ambrisentan, an important endothelin receptor antagonist, was confirmed by single- crystal X-ray diffraction. The three aromatic rings in the lattice are basically orthogonal to one another. There is an intermolecular hydrogen bond in the crystal, which helps to further stabilize the crystal. One of the two non-classical intramolecular hydrogen bonds can help to stabilize the molecular conformation in the lattice.

MUTATION OF THE ENDOTHELIN-B RECEPTOR AND THE ENDOTHELIN-3 GENE IN CHINESE SPORADIC CASES OF HIRSCHSPRUNG'S DISEASE

Objective To investigate the mutation of endothelin receptor B (EDNRB) gene and endothelin 3 (EDN 3) gene in sporadic Hirschsprungs disease (HD) in Chinese population. Methods Genomic DNA was extracted from bowel tissues of 34 unrelated HD patients which were removed by surgery. Exon 3, 4, 6 of EDNRB gene and Exon 1, 2 of EDN 3 gene were amplified by polymerase chain reaction (PCR) and analyzed by single strand conformation polymorphism (SSCP).Results EDNRB mutations were detected in 2 of the 13 short segment HDs. One mutant was in the exon 3; the other one was in the exon 6. EDN 3 mutation was detected in 1 of the 13 short segment HDs and in the exon 2. Both EDNRB mutation and EDN 3 mutation were detected in one short segment HD. No mutations were detected in the ordinary or long segment HD. Conclusion The mutations of EDNRB gene and EDN 3 gene are found in the short segment HD of sporadic Hirschsprung's disease in Chinese population, which suggests that the EDNRB gene and EDN 3 gene play important roles in the pathogenesis of HD. the mutations of EDNRB and EDN 3 lead to the maldevelopment of the enteric nervous system.

Semi-quantitatively Predicting the Residence Time of Three Natural Products on Endothelin Receptor A by Peak Profiling Using the Receptor Functionalized Macroporous Silica Gel as Stationary Phase

Drug-receptor interaction analysis has been broadly adopted as a tool for the evaluation of the drug-like property.Nowadays,growing evidence has demonstrated that drug e fficacy and safety are highly related to residence time,which equals the reciprocal of the dissociation rate constant(k_(d))of a drug to its target protein.Using endothelin receptor A(ET_(A)R)as a probe,we immobilized the receptor on the surface of macroporous silica gel through a covalent interaction between the epidermal growth factor tyrosine kinase(EGFR)at the C terminal of ET_(A)R and the covalent inhibitor ibrutinib modified on the gel in a one-step fashion.The a ffinity stationary phase was used to semi-quantitatively determine the residence time of natural products on ET_(A)R and evaluate their drug-like property.The k_(d)values of three specific ligands(bosentan,macitentan,and ambrisentan)to ET_(A)R were determined by nonlinear chromatography,peak profiling and peak_(d)ecay.Compared the data determined in free solution of the three methods,peak profiling is considered as the best-fit method for k_(d)determination.Thus,peak profiling was applied for predicting the residence time of three natural products(ferulic acid,berberine,and palmatine)on ET_(A)R.With the longest residence time of 61.11±3.47 s on ET_(A)R,palmatine was evaluated as the most potent compound,which could be developed as a long-acting lead for the receptor.We demonstrate that the high-performance a ffinity chromatography with immobilized ET_(A)R is an alternative for the semi-quantitative measurement of residence time for the drug-like property evaluation of natural products.

Pulmonary arterial hyper-tension in a patient with hereditary hemorrhagic telangiectasia and family gene analysis:A case report

BACKGROUND Hereditary hemorrhagic telangiectasia(HHT)is a rare autosomal dominant genetic disease.Very few patients suffering from HHT present with associated pulmonary arterial hypertension(PAH),which may result in a poor prognosis.Here,we report a case of HHT with PAH.The patient’s clinical manifestations and treatment as well as genetic analysis of family members are reviewed,in order to raise awareness of this multimorbidity.CASE SUMMARY A 45-year-old Chinese woman was admitted to the hospital to address a complaint of intermittent shortness of breath,which had lasted over the past 2 years.She also had a 30-year history of recurrent epistaxis and 5-year history of anemia.She reported that the shortness of breath had aggravated gradually over the 2 years.Physical examination discovered anemia and detected gallop rhythm in the precordium.Chest computerized tomography and cardiac ultrasound demonstrated PAH and hepatic arteriovenous malformation.The formal clinical diagnosis was HHT combined with PAH.The patient was treated with ambrisentan and her condition improved for a time.She died half a year after the diagnosis.Genetic testing revealed the patient and some family members to carry an activin A receptor-like type 1 mutation(c.1232G>A,p.Arg411Gln);the family was thus identified as an HHT family.CONCLUSION We report a novel gene mutation(c.1232G>A,p.Arg411Gln)in a Chinese HHT patient with PAH.

Effects of endothelin B receptor antagonists, BQ788 and ET-1_(11-21) fragment on the bronchoconstriction elicited by isocapnic hyperpnea in guinea pigs

Objective To explore the role of endothelin (ET) in the pathogenesis of exercise induced asthma (EIA), we investigated the effects of ET B receptor antagonists, ET 1 11 21 fragment and N cis 2,6 dimethylpi^peridinocardonyl L γ methylleucyl D 1 methoxycarbonyl tryptophanyl D norleucine (BQ788) on broncho^constriction elicited by isocapnic hyperpnea in guinea pigs Methods Eighteen pathogen free Hartley guinea pigs were randomly divided into three groups A: normal saline (NS) inhalation control group (n=6), B: BQ788 group (n=6), and C: ET 1 11 21 fragment group (n=6) Guinea pigs were anesthetized with pentobarbital sodium After measuring the basal value of lung resistance (R L) and dynamic compliance of the respiratory system (Cdyn), NS (0 96?ml), BQ788 (9?nmol) and ET 1 11 21 fragment (9?nmol) were inhaled A rodent respirator with a dry 5%CO 2-95%O 2 mixture at room temperature provided mechanical ventilation (V T 8?ml/animal, 100 breaths/min) for 5?min R L and Cdyn of the 3 groups were measured again after isocapnic hyperpnea challenge Results In the control group, isocapnic hyperpnea of dry gas elicited a marked increase in R L and decrease in Cdyn R L and Cdyn of the guinea pigs from BQ788 group and ET 1 11 21 fragment group did not change significantly Conclusion It was demonstrated that selective ET B receptor antagonists, ET 1 11 21 fragment and BQ788, inhibited the bronchoconstriction induced by isocapnic hyperpnea in guinea pigs The data showed that ETs are potent constrictors of guinea pig airway smooth muscle via a direct effect on ET receptors It was suggested that ET receptor antagonists, especially ET B receptor antagonist, might be beneficial in preventing EIA

内皮素1在内耳的产生、分布及其对内耳内环境的影响

内皮素1是一种具有多种生物学活性的多肽,可由内耳组织细胞产生,在内耳广泛分布并可通过多种方式影响内耳内环境。本文复习近年相关文献,试就上述几个方面的研究现状做一综述。

Effect of kappa elastin on melanogenesis in A375 human melanoma cells and its related mechanism

Background Elastin derived peptides can regulate melanocyte precursor development. Ultraviolet irradiation, infrared radiation and heat can increase the synthesis of tropoelastin in human skin epidermis. The aim of this study was to investigate whether the over expressed tropoelastin in epidermis has some role in melanogenesis of melanocytes. Methods A375 human melanoma cells were treated with different concentrations of kappa elastin for 24 hours. A375 human melanoma cells were randomly assigned to control, kappa elastin, and lactose pre-incubated groups. The cell viabilities were detected by the methyl thiazoleterazolium assay. Melanin content and tyrosinase activity in A375 melanoma cells were measured. The expressions of endothelin B receptor （ETBR） mRNA and c-kit mRNA in A375 melanoma cells were measured by quantative reverse transcription polymerase chain reaction. Results Fifty pg/ml of kappa elastin significantly increased the melanin content by 56.64% compared with the control （P 〈0.05）. Kappa elastin increased cellular tyrosinase activity by 46.73% compared with the control at 24 hours （P 〈0.05）. Kappa elastin increased the expressions of ETBR and c-kit mRNA levels by 2.13-fold and 2.47-fold compared with the controls, respectively. When pre-incubating cells with a lactose solution （10 mmol/L）, the inhibition on melanin production was 34.96% compared with the kappa elastin group （P 〈0.05）, tyrosinase activity was inhibited by 29.93% compared with kappa elastin group （P 〈0.05）, and the expressions of ETBR mRNA and c-kit mRNA were decreased by 1.56-fold and 0.82-fold compared with kappa elastin group, respectively. Conclusion Kappa elastin increased the melanogenesis in A375 melanoma cells via the stimulation of tyrosinase activity and the expression of ETBR and c-kit. The over expressed tropoelastin produced by keratinocytes might play a role in melanogenesis of epidermal melanocytes.