endothelin-1 and Lung-Diseases

Although originally discovered because of their ability to affect hemodynamics, vasoactive peptides have been found to function in a variety of capacities including neurotransmission, endocrine functions, and the regulation of cell proliferation. A growing body of evidence describes the ability of vasoactive peptides to regulate cell death by apoptosis in either a positive or negative fashion depending on the peptide and the type of target cell. The available evidence to date is strongest for the peptides endothelin, angiotensin II, vasoactive intestinal peptide, atrial natriuretic peptide, and adrenomedullin. Each of these peptides is discussed, with specific regard to apoptosis, in terms of regulatory activity, target cell specificity, and potential role in pulmonary physiology.

Topics: Adrenomedullin; Angiotensin II; Animals; Apoptosis; Atrial Natriuretic Factor; Endothelin-1; Humans; Lung; Lung Diseases; Peptides; Vasoactive Intestinal Peptide

Endothelin-1 (ET-1) is a 21 amino acid peptide with diverse biological activity that has been implicated in numerous diseases. ET-1 is a potent mitogen regulator of smooth muscle tone, and inflammatory mediator that may play a key role in diseases of the airways, pulmonary circulation, and inflammatory lung diseases, both acute and chronic. This review will focus on the biology of ET-1 and its role in lung disease.

Topics: Amino Acid Sequence; Endothelin-1; Graft Rejection; Humans; Lung; Lung Diseases; Lung Neoplasms; Lung Transplantation; Molecular Sequence Data; Respiratory Distress Syndrome; Respiratory Tract Diseases; Vascular Diseases

1. There is an increasing amount of research to implicate endothelin (ET)-1, a member of a family of 21 amino acid peptides, as a potentially important mediator in pulmonary diseases, in particular asthma and pulmonary hypertension. Thus, ET-1 fits several of the standard criteria that need to be fulfilled for a pathophysiologically relevant substance. 2. Endothelin-1 is present in abundance in human lung: the major loci for ET-1 are the epithelium, endothelium, endocrine cells and inflammatory cells. Furthermore, the receptors that mediate the biological effects of ET-1, the ETA and ETB receptor subtypes, are found in human lung, predominantly in airway smooth muscle, and vascular smooth muscle and, to a lesser extent, nerves. There is no change in the relative proportions of ETA and ETB receptors in asthmatic versus non-asthmatic bronchial smooth muscle and peripheral lung. 3. Several studies have shown that ET-1 mimics several of the features of asthma (including bronchospasm, airway remodelling, inflammatory cell recruitment and activation, oedema, mucus secretion, airway hyperreactivity and dysfunction in neuronal inputs); however, some other reports are at odds with these findings. 4. Endothelin-1 mimics the two classical features of pulmonary hypertension (pulmonary vascular constriction and remodelling), which is often a serious complication of chronic obstructive pulmonary disease. 5. Intranasal ET-1 produces several of the symptoms of allergic rhinitis. 6. There are several reports of increased levels and/or expression of ET in patients with many pulmonary disorders, in particular asthma or pulmonary hypertension, with some evidence of a correlation between ET amounts and disease severity; however, other studies do not confirm these observations. 7. Despite these intriguing data in support of a pathophysiological role of ET-1 in lung disease, the definitive test and most difficult criteria to fulfil, the clinical evaluation of ET receptor antagonists or ET synthesis inhibitors, has still to be conducted. Only after these pivotal data are available will we be able to determine definitively whether ET-1 is a pathophysiologically important mediator in lung diseases or merely an interesting peptide with several effects in the pulmonary system.

Topics: Asthma; Endothelin Receptor Antagonists; Endothelin-1; Humans; Hypertension, Pulmonary; Lung Diseases; Molecular Mimicry; Receptors, Endothelin

During high intensity exercise, the very high pulmonary artery pressure (Ppa) experienced by Thoroughbred horses is considered a major factor in the aetiology of exercise-induced pulmonary haemorrhage (EIPH). Recently, endothelin-1 (ET-1), a potent vasoconstrictive hormone, has been found to increase Ppa in horses at rest via binding to its ET-1A receptor subtype. In addition, plasma concentrations of ET-1 are increased in horses during and after high intensity exercise.. If ET-1 increases Ppa during exercise in the horse, administration of a specific ET-1A antagonist would decrease Ppa and therefore EIPH.. Saline (CON) or an ET-1A receptor antagonist, TBC3214 (3 mg/kg bwt i.v.; ANTAG) was administered to horses 1 h prior to maximal incremental exercise on a high-speed treadmill. Gas exchange measurements were made breath-by-breath and blood samples collected during each 1 min stage to determine blood gases, acid-base status and cardiac output. EIPH was determined via bronchoalveolar lavage (BAL) approximately 30 min after exercise.. The time to fatigue, gas exchange and cardiovascular responses were not different between groups (P>0.05). Resting and peak Ppa did not differ significantly between treatments. Most importantly, ANTAG did not decrease EIPH.. These results do not support a deterministic role for ET-1 in the increased Ppa and therefore EIPH, during maximal exercise in the equine athlete.. Treatment with an ET-1A receptor antagonist does not appear to be a viable therapeutic intervention in the prevention of EIPH.

Topics: Animals; Blood Chemical Analysis; Blood Gas Analysis; Cross-Over Studies; Endothelin-1; Hemorrhage; Horse Diseases; Horses; Isoxazoles; Lung Diseases; Oxygen Consumption; Physical Conditioning, Animal; Pulmonary Wedge Pressure; Sulfonamides

To investigate the effect of Sanao Tang (SAT) on urine volume and the expression of aquaporin-\ 2 (AQP2) in rats with lung dysfunction induced by passive smoking and lipopolysaccharide.. Totally 45 healthy Specific pathogen Free Wistar Rats were randomized into 3 groups:\ normal control group, model group and SAT group. A rat model of respiratory dysfunction induced by\ exposure to cigarette smoking and lipopolysaccharide (LPS). Lavage of decoction of the Chinese medicine\ was performed for rats in the SAT group. Anires 2005 System was used to analyze the pulmonary\ function. Urine of rats was collected through metabolism cage method. Enzyme-linked immunosorbent\ assay (ELISA) was used to determine content of antidiuretic hormone (ADH), angiotensin Ⅱ (AngⅡ), atrial natriuretic factor (ANP), endothelin 1 (ET-1), nitric oxide (NO) and prostaglandin E2\ (PGE2) in serum, lung and kidney. The expression of AQP2 in rat renal tissue was determined with \ real-time fluorescence quantitative PCR (RT-PCR).. (a) In comparison with the normal control, It was found that enforced vital capacity (FVC),\ 1-second forced expiratory volume/forced vital capacity% (FEV(1)/FVC%), 24 h urine volume content of\ NO and PGE2 were decreased, while AQP2mRNA level and content of ADH, Agn Ⅱ, ANP and ET-1\ were increased in the model group with statistical significance (P < 0.05). (b) In comparison with the\ model group, It was found that FVC, FEV(1), FEV(1)/FVC%, 24 h urine volume, content of PGE2 and NO\ decreased, while AQP2mRNA level, content of ANP, ADH and Ang Ⅱ decreased in the SAT group with\ statistical significance (P < 0.05).. SAT might effectively regulate the urine volume in the modeled rats; ADH, Ang Ⅱ,\ ANP, ET-1, NO and PGE2 might play an important role in the regulation on urine volume by lungs.\ This might be the mechanisms underpinning the function of lung governing water passage in terms\ of the theory of Traditional Chinese Medicine.

Topics: Angiotensin II; Animals; Aquaporin 2; Dinoprostone; Drugs, Chinese Herbal; Endothelin-1; Humans; Lipopolysaccharides; Lung; Lung Diseases; Male; Nicotiana; Rats; Rats, Wistar; Tobacco Smoke Pollution; Urination; Vasopressins

This study was designated to estimate protective role of ETA and ETB receptor antagonist against endothelin 1 (ET-1)-induced oxidative stress in lungs and determine whether these effects are mediated by nitric oxide (NO) synthase. Experiments were performed on Wistar rats divided into the following groups: I - saline (0.9 % NaCl); II - ET-1 (3 microg/kg b.w.), III - BQ123 (1 mg/kg b.w.) + ET-1 (3 microg/kg b.w.), IV - BQ788 (3 mg/kg b.w.) + ET-1 (3 microg/kg b.w.), V - N-nitro-L-arginine methyl ester (L-NAME) (5 mg/kg b.w.) + ET-1 (3 microg/kg b.w.). ETA and ETB receptor antagonists or L-NAME were administered 30 min before ET-1 injection. The levels of the following substances were measured in the lungs homogenates: thiobarbituric acid reactive substances (TBARS), hydrogen peroxide (H(2)O(2)), reduced glutathione (GSH) and tumor necrosis factor-alpha (TNF-alpha). The results showed that ET-1 significantly increased TBARS, H(2)O(2) (respectively: p<0.001, p<0.02) and TNF-alpha levels (p<0.02) and decreased the GSH level (p<0.01) vs.. On the other hand, prior administration of ETA receptor blocker (BQ123) significantly attenuated TBARS (p<0.01), H(2)O(2) (p<0.02), TNF-alpha (p<0.02) and increased GSH (p<0.02) levels vs. ET-1. However, prior administration of ETB receptor blocker BQ788 did not cause significant changes in the: TBARS, H(2)O(2) and TNF-alpha (p>0.05) levels, but significantly increased the GSH level and GSH/GSSG ratio (p<0.05). Administration of L-NAME significantly attenuated TBARS (p<0.001), H(2)O(2) (p<0.05), TNF-alpha (p<0.01) and increased GSH (p<0.05) levels vs. ET-1. In conclusion, we demonstrated that ET-1 induced oxidative stress in the lungs is mediated by ETA receptors. ETA receptor blockage inhibited generation of free radicals and TNF-alpha and ameliorated antioxidant properties. Moreover, generation of reactive oxygen species is mediated by NOS in the lungs.

Topics: Animals; Endothelin Receptor Antagonists; Endothelin-1; Glutathione; Hydrogen Peroxide; Lipid Peroxidation; Lung; Lung Diseases; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase; Oligopeptides; Oxidative Stress; Peptides, Cyclic; Piperidines; Random Allocation; Rats, Wistar; Reactive Oxygen Species; Receptor, Endothelin A; Receptor, Endothelin B; Tumor Necrosis Factor-alpha

Despite increase in survival of HIV patients due to highly active antiretroviral therapy (HAART), non-infectious complications are still prevalent such as presentation of lung vasculopathy, even in asymptomatic patients. Endothelin-1 (ET-1) is a potent vasoconstrictor that causes pulmonary vasculopathy. Participation of this protein in the pulmonary circulation in HIV patients has not been elucidated. In this work we studied the presence and expression of ET-1 in pulmonary complex vascular lesions associated with human immunodeficiency virus (PCVL/HIV).. We used immunohistochemistry and immunochemiluminescence (imagej) to determine the different degrees of expression of ET-1 in PCVL/HIV in comparison with non-PCVL/HIV. Reagents used were anti-endothelin-1 and an automated system. All data are presented as mean and standard deviation (SD). Differences were analyzed with one-way ANOVA; p < 0.05 was accepted as statistically significant.. Lung tissues from 56 patients who died from complications of HIV pulmonary infection and with PCVL were studied. Histological evidence of pulmonary vasculopathy was shown as different types (proliferative, obliterative and plexiform). A statistically significant increase in ET-1 expression was observed in all PCVL/HIV tissue samples and is associated directly with different grades of severity of endothelial dysfunction.. ET-1 has a relevant role in the pathogenesis of pulmonary vasculopathy in acquired immunodeficiency syndrome (AIDS) patients. It is necessary to determine in the future the participation of ET-1 and other mechanisms involved in PCVL/HIV.

Topics: Acquired Immunodeficiency Syndrome; Adult; Endothelin-1; Female; Humans; Lung; Lung Diseases; Male; Middle Aged; Pulmonary Artery; Pulmonary Circulation; Vascular Diseases; Young Adult

Heart and pulmonary involvement is a leading cause of systemic sclerosis (SSc)-related deaths.. The aim of our study was to assess if biochemical markers of right ventricular (RV) overload, endothelial function and collagen metabolism can predict RV dysfunction assessed by Doppler echocardiography in SSc patients.. We prospectively studied 111 consecutive patients (101 F, 10 M, age 54.2 ± 13.8 years) with diagnosed SSc (mean disease duration 9.4 ± 11.4 years) and a group of 21 age-matched subjects (18 F, 3 M, age 49.3 + 10.5 years). We performed transthoracic echocardiography (Phillips iE 33) and measured serum endothelin-1 (ET-1), N-terminal pro-brain natriuretic peptide (NT-proBNP), asymmetric dimethylarginine (ADMA), endoglin and human tissue inhibitor of matrix metalloproteinase (TIMP-1) concentration.. Median serum NT-proBNP level in SSc patients was 133.5 (range 21.86-17,670 pg/ml) and was significantly higher than in controls (p = 0.0002). Moreover, the median serum ET-1 level of 1.49 (range 0.26-8.75 pg/ml) was higher in SSc patients (p = 0.002). However, no significant differences in ADMA, TIMP-1 and endoglin serum concentration between SSc patients and controls were observed. Serum NT-proBNP concentration correlated positively with echocardiographic signs of RV overload: tricuspid regurgitation pressure gradient (r = 0.38, p = 0.0004) and RV Tei index (r = 0.25, p = 0.01). ET-1 serum level correlated negatively with tricuspid annular plane systolic excursion (r = -0.4, p = 0.01) and positively with inferior vena cava diameter measured at expiration (r = 0.38, p = 0.0002). The echocardiographic signs of RV overload were significantly more pronounced in the highest NT-proBNP tertile (>195 pg/ml) group than in the lowest one (<88 pg/ml).. Serum ET-1 and NT-proBNP, but not endoglin, ADMA and TIMP-1 levels correlating with the echocardiographic parameters of RV overload, can be considered as noninvasive indicators of RV dysfunction in SSc patients.

Topics: Adult; Aged; Antigens, CD; Arginine; Biomarkers; Case-Control Studies; Collagen; Echocardiography; Echocardiography, Doppler; Endoglin; Endothelin-1; Endothelium, Vascular; Female; Fibrosis; Humans; Lung Diseases; Male; Middle Aged; Natriuretic Peptide, Brain; Peptide Fragments; Prospective Studies; Receptors, Cell Surface; Scleroderma, Systemic; Tissue Inhibitor of Metalloproteinase-1; Ventricular Function, Right

Many studies of human subjects have demonstrated the utility of assessing serum levels of endothelin-1 (ET-1) and big ET-1 as clinical biomarkers in cardiopulmonary and neoplastic diseases. In this study we explored the feasibility of using serum big ET-1 as a reliable veterinary marker in dogs with various cardiopulmonary and neoplastic diseases.. Serum big ET-1 levels were measured by ELISA in dogs with cardiopulmonary (n=21) and neoplastic diseases (n=57). Dogs exhibiting cardiopulmonary disease were divided into two groups based on the velocity of tricuspid valve regurgitation (3.0>m/s) measured by ultrasound: without and with pulmonary hypertension. Big ET-1 levels for the dogs with the diseases were compared with levels in normal healthy dogs (n=17).. Dogs with cardiopulmonary disease (4.6±4.6 pmol/l) showed a significantly (P<0.01) higher level of big ET-1 than healthy control dogs (1.1±0.53 pmol/l). Serum levels in the dogs with pulmonary hypertension (6.2±5.3 pmol/l) were significantly (P<0.01) higher than those without pulmonary hypertension (2.0±0.6 pmol/l). Dogs with hemangiosarcoma (5.6±2.2 pmol/l), adenocarcinoma (2.0±1.8 pmol/l), histiocytic sarcoma (3.3±1.9 pmol/l), chondrosarcoma or osteosarcoma (3.0±1.6 pmol/l) and hepatocellular carcinoma (2.7±1.8 pmol/l) showed significantly (P<0.05) higher levels than healthy control dogs.. These findings point to the potential of serum big ET-1 as a clinical marker for cardiopulmonary and neoplastic diseases in dogs.

Topics: Animals; Biomarkers; Cardiovascular Diseases; Dogs; Endothelin-1; Female; Humans; Lung Diseases; Male; Natriuretic Peptide, Brain; Neoplasms; Peptide Fragments

End-stage renal disease (ESRD) is a complex illness that involves different organs including the lungs. We studied the pulmonary function tests, arterial blood gases (ABG) and plasma endothelin-1 (ET-1) levels to check whether there is any change in their levels after hemodialysis (HD) in patients with ESRD. In this cross-sectional study (from July 2009 to April 2010), 20 patients with ESRD were evaluated. ABG, spirometric parameters and plasma ET-1 were measured before and after HD in these patients. Student's t-test was performed to clarify the differences and Pearson's test was used for correlations. P <0.05 was considered statistically significant. Significant reduction was seen in oxygen saturation (O₂sat), partial pressure of carbon-dioxide (PaCO₂) and oxygen (PaO₂) after a HD session (P <0.001). Also, improvement was seen in all spirometric parameters except forced expiratory volume (FEV1)/forced vital capacity (FVC) after HD. Plasma ET-1 levels decreased significantly after HD. Mean ET-1 before HD was 6.88 + 5.81 pg/mL while it was 3.91 + 2.76 pg/mL after HD (P = 0.009). Based on the plasma levels of ET-1, the patients were divided into two groups. The mean level of ET-1 was higher in the first group. Significant increase was seen in spirometric parameters in the second group. Our study suggests that, in patients with ESRD, plasma ET-1 level is higher than in the normal population, and this is closely related to deterioration of pulmonary function tests. Significant reduction of plasma ET-1 may be an important factor in the improvement of spiro-metry parameters after HD.

Topics: Adult; Biomarkers; Blood Gas Analysis; Cross-Sectional Studies; Endothelin-1; Female; Forced Expiratory Volume; Humans; Kidney Failure, Chronic; Lung; Lung Diseases; Male; Middle Aged; Recovery of Function; Renal Dialysis; Respiratory Function Tests; Treatment Outcome; Vital Capacity; Young Adult

Differentiation of fibroblasts into α-smooth muscle actin (SMA)-expressing myofibroblasts represents a critical step in the pathogenesis of fibrotic disorders, and is generally regarded as irreversible. Prostaglandin E2 (PGE2) has been shown to prevent multiple aspects of fibroblast activation, including the differentiation of fibroblasts to myofibroblasts. Here, we investigated its ability to reverse this differentiated phenotype. Fetal and adult lung fibroblasts were induced to differentiate into myofibroblasts by 24-hour culture with transforming growth factor (TGF)-β1 or endothelin-1. Cells were then treated without or with PGE2 for various intervals and assessed for α-SMA expression. In the absence of PGE2 treatment, α-SMA expression induced by TGF-β1 was persistent and stable for up to 8 days. By contrast, PGE2 treatment effected a dose-dependent decrease in α-SMA and collagen I expression that was observed 2 days after PGE2 addition, peaked at 3 days, and persisted through 8 days in culture. This effect was not explained by an increase in myofibroblast apoptosis, and indeed, reintroduction of TGF-β1 2 days after addition of PGE2 prompted dedifferentiated fibroblasts to re-express α-SMA, indicating redifferentiation to myofibroblasts. This effect of PGE2 was associated with inhibition of focal adhesion kinase signaling, and a focal adhesion kinase inhibitor was also capable of reversing myofibroblast phenotype. These data unambiguously demonstrate reversal of established myofibroblast differentiation. Because many patients have established or even advanced fibrosis by the time they seek medical attention, this capacity of PGE2 has the potential to be harnessed for therapy of late-stage fibrotic disorders.

Topics: Actins; Antigens, Differentiation; Apoptosis; Cell Differentiation; Cell Line; Collagen Type I; Dinoprostone; Endothelin-1; Fibrosis; Focal Adhesion Protein-Tyrosine Kinases; Gene Expression; Humans; Lung; Lung Diseases; Myofibroblasts; Phenotype; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerases; Signal Transduction; Transforming Growth Factor beta1

Patients with cirrhosis exhibit impaired regulation of the arterial blood pressure, reduced baroreflex sensitivity (BRS), and prolonged QT interval. In addition, a considerable number of patients have a pulmonary dysfunction with hypoxemia, impaired lung diffusing capacity (Dl(CO)), and presence of hepatopulmonary syndrome (HPS). BRS is reduced at exposure to chronic hypoxia such as during sojourn in high altitudes. In this study, we assessed the relation of BRS to pulmonary dysfunction and cardiovascular characteristics and the effects of hyperoxia. Forty-three patients with cirrhosis and 12 healthy matched controls underwent hemodynamic and pulmonary investigations. BRS was assessed by cross-spectral analysis of variabilities between blood pressure and heart rate time series. A 100% oxygen test was performed with the assessment of arterial oxygen tensions (Pa(O(2))) and alveolar-arterial oxygen gradient. Baseline BRS was significantly reduced in the cirrhotic patients compared with the controls (4.7 +/- 0.8 vs. 10.3 +/- 2.0 ms/mmHg; P < 0.001). The frequency-corrected QT interval was significantly prolonged in the cirrhotic patients (P < 0.05). There was no significant difference in BRS according to presence of HPS, Pa(O(2)), Dl(CO), or Child-Turcotte score, but BRS correlated with metabolic and hemodynamic characteristics. After 100% oxygen inhalation, BRS and the QT interval remained unchanged in the cirrhotic patients. In conclusion, BRS is significantly reduced in patients with cirrhosis compared with controls, but it is unrelated to the degree of pulmonary dysfunction and portal hypertension. Acute hyperoxia does not significantly revert the low BRS or the prolonged QT interval in cirrhosis.

Topics: Aged; Aldosterone; Angiotensin II; Atrial Natriuretic Factor; Baroreflex; Case-Control Studies; Endothelin-1; Female; Humans; Hyperoxia; Liver Cirrhosis, Alcoholic; Lung Diseases; Male; Middle Aged; Natriuretic Peptide, Brain; Norepinephrine; Oxygen; Renin

Peak oxygen uptake (peak VO(2)) is a predictor of outcome in patients with lung disease. In these patients, peak VO(2) is typically determined by ventilation and gas exchange. However, it is not well known whether cardiac strain contributes to peak VO(2) in patients with chronic lung disease.. To assess the relationship between several novel biomarkers reflecting different aspects of cardiac function and peak VO(2) in patients with chronic lung disease.. Plasma concentrations of midregional pro-A-type natriuret- ic peptide (MR-proANP), midregional proadrenomedullin (MR-proADM), C-terminal proendothelin-1 (CT-proET-1), and C-terminal provasopressin (copeptin) were measured in 85 patients with a variety of chronic pulmonary diseases [age 57 ± 14 years, forced expiratory volume in the 1st second (FEV(1)) 76 ± 23% of the predicted value] undergoing maximal cardiopulmonary exercise testing (peak VO(2) 18.6 ± 6.6 ml/kg/min).. Raised MR-proANP (r = -0.54), MR- proADM (r = -0.54), and CT-proET-1 (r = -0.49; p < 0.001 for all) but not copeptin (r = -0.05; p = 0.68) concentrations were associated with lower peak VO(2), and these associations were independent of age, gender, medication, FEV(1) and oxygenation. The relationship between MR-proANP, MR-proADM, and CT-proET-1 and peak VO(2) was significant whether patients had an obstructive ventilatory disease or not.. In patients with chronic lung disease, several biomarkers known to reflect measures of cardiac function were associated with peak VO(2) independent of lung function, indicating that cardiac strain may contribute to exercise limitation in these patients due to concomitant cardiac disease or in the context of a pulmonary-cardiac interaction.

Topics: Adrenomedullin; Adult; Aged; Atrial Natriuretic Factor; Biomarkers; Endothelin-1; Female; Forced Expiratory Volume; Humans; Lung Diseases; Male; Middle Aged; Oxygen Consumption; Peptide Fragments; Protein Precursors; Vital Capacity

Contact of blood with artificial surfaces and air as well as ischemia/reperfusion injury to the heart and lungs mediate systemic and local inflammation during cardiopulmonary bypass (CPB). Activation of complement and coagulation cascades leads to and accompanies endothelial cell damage. Therefore, endothelial-targeted cytoprotection with the complement inhibitor and endothelial protectant dextran sulfate (DXS, MW 5000) may attenuate CBP-associated myocardial and pulmonary injury.. Eighteen pigs (DXS, n=10; phosphate buffered saline [PBS], n=8) underwent standard cardiopulmonary bypass. After aortic cross-clamping, cardiac arrest was initiated with modified Buckberg blood cardioplegia (BCP), repeated after 30 and 60 min with BCP containing either DXS (300 mg/10 ml, equivalent to 5mg/kg) or 10 ml of PBS. Following 30 min reperfusion, pigs were weaned from CPB. During 2h of observation, cardiac function was monitored by echocardiography and invasive pressure measurements. Inflammatory and coagulation markers were assessed regularly. Animals were then sacrificed and heart and lungs analyzed.. DXS significantly reduced CK-MB levels (43.4+/-14.8 ng/ml PBS, 35.9+/-11.1 ng/ml DXS, p=0.042) and significantly diminished cytokine release: TNFalpha (1507.6+/-269.2 pg/ml PBS, 222.1+/-125.6 pg/ml DXS, p=0.0071), IL1beta (1081.8+/-203.0 pg/ml PBS, 110.7+/-79.4 pg/ml DXS, p=0.0071), IL-6 (173.0+/-91.5 pg/ml PBS, 40.8+/-19.4 pg/ml DXS, p=0.002) and IL-8 (304.6+/-81.3 pg/ml PBS, 25.4+/-14.2 pg/ml DXS, p=0.0071). Tissue endothelin-1 levels were significantly reduced (6.29+/-1.90 pg/100mg PBS, 3.55+/-1.15 pg/100mg DXS p=0.030) as well as thrombin-anti-thrombin formation (20.7+/-1.0 microg/ml PBS, 12.8+/-4.1 microg/ml DXS, p=0.043). Also DXS reduced cardiac and pulmonary complement deposition, neutrophil infiltration, hemorrhage and pulmonary edema (measured as lung water content, 81+/-3% vs 78+/-3%, p=0.047), indicative of attenuated myocardial and pulmonary CPB-injury. Diastolic left ventricular function (measured as dp/dt(min)), pulmonary artery pressure (21+/-3 mmHg PBS, 19+/-3 mmHg DXS, p=0.002) and right ventricular pressure (21+/-1 mmHg PBS, 19+/-3 mmHg DXS p=0.021) were significantly improved with the use of DXS.. Addition of DXS to the BCP solution ameliorates post-CPB injury and to a certain extent improves cardiopulmonary function. Endothelial protection in addition to myocyte protection may improve post-CPB outcome and recovery.

Topics: Animals; Blood Coagulation; Cardiopulmonary Bypass; Complement Hemolytic Activity Assay; Dextran Sulfate; Disease Models, Animal; Drug Evaluation, Preclinical; Endothelin-1; Heart Arrest, Induced; Hemodynamics; Inflammation Mediators; Lung Diseases; Myocardial Reperfusion Injury; Pulmonary Edema; Reperfusion Injury; Sus scrofa

Acute lung injury (ALI) induced by phosgene increases risk of serious edema and mortality. Increased permeability of the microvascular endothelium is implicated in the progression of ALI, but the processing interaction and time course activity of the vascular regulators in exudation are still not understood. The main aim of this study was to investigate the time course and potential role for vascular endothelial growth factor (VEGF), its receptors, and some vascular function regulators related to increased vascular permeability of lung induced by phosgene. Sprague Dawley rats were randomly divided into seven groups according to time post phosgene exposure (control, and 1, 3, 6, 12, 24, and 48 h groups). Lung tissue was removed to evaluate VEGF isoforms, fms-like tyrosine kinase receptor 1 (Flt-1), and kinase insert domain containing region (KDR/Flk-1) by reverse-transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Blood samples were collected for measurement of plasma endothelin-1 (ET-1) and nitric oxide (NO) level. The results showed that the mRNA and protein expression profile of the VEGF system after phosgene exposure was time dependent. The VEGF system expression in lung tissue was related closely to the level of ET-1 and NO. In conclusion, increased permeability of the lung microvascular endothelium induced by phosgene was primarily a result of differential expression of VEGF and its receptors, and was related to the level of ET-1 and NO. The results suggest that the cooperation of VEGF system, ET-1, and NO plays a critical role, and all those parameters emerge as time dependent in the early phase of the permeability process induced by phosgene exposure.

Topics: Animals; Capillary Permeability; Chemical Warfare Agents; Endothelin-1; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Gene Expression; Lung; Lung Diseases; Male; Microcirculation; Nitric Oxide; Phosgene; Pulmonary Circulation; Rats; Rats, Sprague-Dawley; Receptors, Vascular Endothelial Growth Factor; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-1; Vascular Endothelial Growth Factor Receptor-2

We designed the present experiments to investigate the involvement of endogenous nitric oxide synthase (NOS) inhibitors, dimethylarginine dimethylaminohydrolase (DDAH) as a hydrolyzing enzyme of the NOS inhibitors, NOS, arginase which shares l-arginine as a common substrate with NOS, and endothelin-1 (ET-1) in the pulmonary dysfunction after induction of experimental subarachnoid hemorrhage (SAH) in the rabbit. SAH was induced by injecting autologous blood into the cisterna magna, and controls were injected with saline. On day 2, pulmonary arteries were isolated for determinations. A significant impairment of the endothelium-dependent relaxation (EDR) caused by acetylcholine was found in 20 cases (43.5%) out of 46 SAH animals, and the same animals exhibited accompanying the significantly impaired cyclic GMP production, accumulated endogenous NOS inhibitors, attenuated DDAH activity, enhanced arginase activity and accumulated ET-1 within the vessel wall. Meanwhile, there were no differences in endothelial NOS activity per se and sodium nitroprusside-induced relaxation between the animals with an impaired EDR and those without such a change. ET-1 content within aortic wall was increased with concomitant decrease in cyclic GMP production after the intraperitoneal application of authentic monomethylarginine as a NOS inhibitor in the rat. The current results suggest that accumulated endogenous NOS inhibitors and enhanced arginase activity possibly bring about the impaired NO production, thereby attenuating the EDR and contributing to the accumulation of ET-1 within the vessel wall. The accumulated endogenous NOS inhibitors at least partly result from the decreased DDAH activity. These alterations may be relevant to the pulmonary dysfunction after induction of SAH.

Topics: Acetylcholine; Amidohydrolases; Animals; Arginase; Cyclic GMP; Cyclooxygenase Inhibitors; Dose-Response Relationship, Drug; Endothelin-1; Indomethacin; Lung Diseases; Male; Models, Biological; Nitric Oxide Donors; Nitric Oxide Synthase; Nitroarginine; Nitroprusside; omega-N-Methylarginine; Oxadiazoles; Pulmonary Artery; Quinoxalines; Rabbits; Rats; Rats, Sprague-Dawley; Subarachnoid Hemorrhage; Vasoconstriction

As prolonged hyperoxia induces extensive lung tissue damage, we set out to investigate the involvement of endothelin-1 (ET-1) receptors in these adverse changes.. Experiments were performed on four groups of mice: control animals kept in room air and a group of mice exposed to hyperoxia for 60 h were not subjected to ET-1 receptor blockade, whereas the dual ETA/ETB-receptor blocker tezosantan (TEZ) was administered via an intraperitoneal pump (10 mg/kg/day for 6 days) to other groups of normal and hyperoxic mice. The respiratory system impedance (Zrs) was measured by means of forced oscillations in the anesthetized, paralyzed and mechanically ventilated mice before and after the iv injection of ET-1 (2 microg). Changes in the airway resistance (Raw) and in the tissue damping (G) and elastance (H) of a constant-phase tissue compartment were identified from Zrs by model fitting.. The plasma ET-1 level increased in the mice exposed to hyperoxia (3.3 +/- 1.6 pg/ml) relative to those exposed to room air (1.6 +/- 0.3 pg/ml, p < 0.05). TEZ administration prevented the hyperoxia-induced increases in G (13.1 +/- 1.7 vs. 9.6 +/- 0.3 cmH2O/l, p < 0.05) and H (59 +/- 9 vs. 41 +/- 5 cmH2O/l, p < 0.05) and inhibited the lung responses to ET-1. Hyperoxia decreased the reactivity of the airways to ET-1, whereas it elevated the reactivity of the tissues.. These findings substantiate the involvement of the ET-1 receptors in the physiopathogenesis of hyperoxia-induced lung damage. Dual ET-1 receptor antagonism may well be of value in the prevention of hyperoxia-induced parenchymal damage.

Topics: Airway Resistance; Animals; Endothelin-1; Female; Hyperoxia; Lung; Lung Diseases; Mice; Mice, Inbred C57BL; Models, Biological; Pyridines; Receptors, Endothelin; Tetrazoles; Time Factors; Vasodilator Agents

Inhalation of endothelin (ET)-A receptor antagonists has been shown to improve gas exchange in experimental acute lung injury (ALI) but may induce side effects by increasing circulating ET-1 levels. We investigated whether the inhaled ET(A) receptor antagonist, LU-135252, at low doses, improves gas exchange without affecting ET-1 plasma concentrations and lung injury in an animal model of ALI. Twenty-two piglets were examined in a prospective, randomized, controlled study. In anesthetized animals, ALI was induced by surfactant depletion. Animals received either LU-135252 at a dose of 0.3 mg/kg during 20 mins (LU group; n = 11), or nebulization of saline buffer (control group; n = 11). The Mann-Whitney U test was used to compare groups (P < 0.05). In the LU group, arterial partial pressure of oxygen (PaO2) and mean pulmonary artery pressure (MPAP) improved compared with the control group (PaO2, 319 +/- 44 mm Hg vs. 57 +/- 3 mm Hg; MPAP, 32 +/- 2 mm Hg vs. 41 +/- 2 mm Hg; values at 6 hrs after induction of ALI; P < 0.05). Mean arterial pressure and cardiac output were not different between groups. ET-1 plasma concentrations increased from 0.96 +/- 0.06 fmol/ml after induction of ALI to a maximum of 1.17 +/- 0.09 fmol/ml at 3 hrs after ALI onset in the LU group and did not differ significantly from the control group (1.21 +/- 0.08 fmol/ml, not significant). On histologic examination, we found no differences in total lung injury score between groups. However, the LU group revealed significantly reduced interstitial inflammation and hemorrhage (P < 0.05 vs. control group). In this animal model of ALI, inhalation of LU-135252 at a dose of 0.3 mg/kg induced a significant and sustained improvement in gas exchange, whereas there were no changes in ET-1 plasma concentrations. Furthermore, our data indicate a trend toward decreased pulmonary inflammation in the group receiving the inhaled ET(A) receptor antagonist.

Topics: Acute Disease; Administration, Inhalation; Animals; Blood Pressure; Cardiac Output; Dose-Response Relationship, Drug; Endothelin A Receptor Antagonists; Endothelin-1; Inflammation; Lung Diseases; Phenylpropionates; Prospective Studies; Pulmonary Gas Exchange; Pyrimidines; Random Allocation; Swine

Endothelin-1 (ET-1) is increasingly recognized as a proinflammatory mediator in various diseases, such as atherosclerosis and acute respiratory distress syndrome (ARDS). Angiopoietin-1 (Ang-1), a ligand of the endothelial receptor Tie2, inhibits endothelial apoptosis, reduces vascular leakage, and suppresses the induction of inflammatory markers, indicating that it has diverse vasoprotective, anti-inflammatory actions. Thus, we examined the effects of Ang-1 on ET-1 production in vitro and in vivo and investigated cell-based gene transfer of Ang-1 in a rat model of lipopolysaccharide (LPS)-induced ARDS. Cultured human endothelial cells were treated with recombinant Ang-1 with or without tumor necrosis factor-alpha (TNF-alpha) (100 U/ml). ET-1 release into the culture medium after 24 hrs was determined by enzyme-linked immunosorbent assay. Levels of preproendothelin-1 (ppET-1) mRNA were measured by quantitative reverse transcription-polymerase chain reaction. Fisher344 rats were subjected to cell-based gene transfer to the lung circulation by injecting syngeneic fibroblasts transfected with Ang-1 cDNA or a null plasmid vector. After 24 hrs, LPS (100 microg/kg body wt) was instilled intratracheally to induce pulmonary inflammation. Bronchoalveolar lavage was performed 6 hrs later, and lungs were harvested for histologic and molecular analyses. ET-1 release from cultured endothelial cells was dose-dependently reduced by Ang-1, which also prevented induction of ET-1 release by TNF-alpha (P < 0.05). RNA expression of ppET-1 was similarly reduced. In LPS-challenged lungs, ppET-1 RNA was induced 3.4-fold, and ET-1 protein in lavage fluid was increased 5.6-fold (P < 0.05). Ang-1 gene transfer attenuated the LPS-induced increases in ppET-1 RNA and lavage ET-1 protein by 34% and 33%, respectively (P < 0.05). The downregulation of ET-1 correlated with the amelioration of pulmonary inflammation, as indicated by reductions in leukocyte infiltration (by 43%) and intra-alveolar septal thickening (by 40%). These results show that ET-1 transcript and protein levels are downregulated by Ang-1 in both in vitro and in vivo systems and that cell-based Ang-1 gene transfer markedly ameliorated inflammation in vivo in an experimental model of ARDS. Thus, cell-based gene transfer of Ang-1 may provide a novel treatment strategy for ARDS by attenuating vascular inflammation via suppression of ET-1.

Topics: Angiopoietin-1; Animals; Cells, Cultured; Culture Media; Dose-Response Relationship, Drug; Down-Regulation; Endothelin-1; Endothelium, Vascular; Fibroblasts; Gene Expression Regulation; Gene Transfer Techniques; Inflammation; Lung Diseases; Male; Random Allocation; Rats; Rats, Inbred F344; Skin

To study the role of endothelin (ET-1) and adrenomedullin (AM) on pulmonary vascular pressure/flow characteristic (pulmonary arterial pressure/cardiac output (Pap/CO)) during low-dose dobutamine infusion.. Case control study of 14 patients (12 men, 2 women) with severe lung disease (chronic obstructive pulmonary disease, COPD n=5; cystic fibrosis, CF n=9) and 5 control subjects (CTRL, 4 men, 1 woman). ET-1 and AM plasma levels in pulmonary artery (mixed venous blood, ven) and aorta or femoral artery (arterial, art), were measured at baseline and during dobutamine infusion (5-10-15 mcg kg(-1) min(-1)). The Ppa/CO coordinates obtained at baseline and during dobutamina infusion for each patients were used to calculate the Slope and Intercept by linear regression analysis.. Baseline hemodynamics measurements were similar in the three groups with a trend towards a mild elevation in Ppa in CF group (Ppa mm Hg: CTRL 19+/-3.5, COPD 19.4+/-5.5, CF 22.7+/-7.5). Baseline plasma ET-1(ET-1ven pg ml(-1): CTRL 13.9+/-6.7, COPD 20.1+/-14, CF 20.4+/-7.1; ET-1art pg ml(-1): CTRL 16.7+/-6.4, COPD 20.1+/-11.7, CF 18.1+/-3.9) and AM (AMven pg ml(-1): CTRL 15.8+/-5, COPD 31.8+/-17.6, CF 27.7+/-7.6; AMart pg ml(-1): CTRL 15.9+/-1.4, COPD 21.4+/-3.8, CF 27+/-7.6) showed a trend towards higher value among patients' groups compared to the controls. Baseline ET-1 pulmonary gradient did not show significant difference among the three groups as well AM pulmonary gradient. Dobutamine infusion caused a comparable increase of heart rate and CO in the three groups. Mean pulmonary pressure had a trend towards a greater increase in COPD and CF than in controls, consequently, pulmonary Pap/CO relationship showed a steeper slope in patients' groups (Slope mm Hg L(-1) min(-1): CTRL 0.9+/-0.3, COPD 2.1+/-0.8 p<0.02 vs. CTRL, CF 1.9+/-0.9 p<0.03 vs CTRL). During dobutamine plasma ET-1 and AM showed a great individual variability resulting in no significant difference among groups. ET-1 pulmonary gradient showed a trend towards pulmonary uptake in patients' groups (ET-1art-ven pg min(-1): CTRL 2.7+/-2.9, COPD-6.1+/-7.8, CF -4+/-4.8) while AM pulmonary gradient did not show any particular pattern. During dobutamine ET-1 was significantly correlated to Pap/CO characteristics (Slope and ET-1ven, r=-0.59, p<0.05; Slope and ET-1art-ven, r=-0.60, p<0.05; Intercept and ET-1art-ven, r=0.63, p<0.004), and ET-1art-ven was the only independent variable related to Slope and Intercept.. In patients with moderate pulmonary vascular impairment, ET-1 pulmonary gradient, but not AM pulmonary gradient, is inversely correlated with pulmonary incremental resistance, suggesting a role of ET-1 in the regulation of pulmonary vascular resistance.

Topics: Adrenergic beta-Agonists; Adrenomedullin; Adult; Aged; Blood Pressure; Dobutamine; Endothelin-1; Female; Humans; Lung; Lung Diseases; Male; Middle Aged; Multivariate Analysis; Peptides; Pulmonary Circulation; Respiratory Function Tests

To compare the accuracy of biomarkers for identifying acute chest syndrome (ACS) in patients with sickle cell disease presenting to a pediatric emergency department (ED).. We conducted a 13-month-long (2002-2003) cohort study with nested case-control in patients with sickle cell disease presenting to the pediatric ED with vaso-occlusive crises or fever in which we compared levels of secretory phospholipase A2 (sPLA2), endothelin-1, interleukin-6 (IL-6), and peripheral white blood cell count (WBC) in cases that were complicated by ACS and in control subjects with uncomplicated illnesses. For diagnosis, a test was considered to be accurate when the area under its receiver operator characteristic curve (AUC) was >0.70. Laboratory tests with AUC values > or =0.70 were entered into a binary recursive partitioning model for diagnosis.. For the period of study, samples from 72 visits were obtained from 51 patients who presented with vaso-occlusive crises (range: 1-4 visits per patient; 15 were enrolled more than once). ACS complicated 19 of 72 visits (26%, 95% confidence interval: 17%-38%). At an AUC value of 0.79, only the sPLA2 test was accurate for diagnosing ACS. AUC values for peripheral WBC, endothelin-1, and IL-6 were 0.68, 0.51, and 0.52, respectively. Binary recursive partitioning retained only sPLA2 at a cutoff of 13.7 ng/mL to be accurate for diagnosis. This cutoff had a sensitivity of 74% (14 of 19), a specificity of 87% (46 of 53), a positive likelihood ratio of 5.6, and a negative likelihood ratio of 0.18.. Secretory phospholipase A2 but not endothelin-1, IL-6, or WBC is an accurate test for identifying present or incipient ACS in young patients who present to the ED with sickle cell pain crises.

Topics: Acute Disease; Adolescent; Anemia, Sickle Cell; Area Under Curve; Biomarkers; Chest Pain; Child; Endothelin-1; Female; Humans; Interleukin-6; Leukocyte Count; Lung Diseases; Male; Phospholipases A; Phospholipases A2; Sensitivity and Specificity; Syndrome

To observe the phenomenon of pulmonary hemorrhage (PH) induced by exogenous endothelin-1 (exET-1) and the antagonizing effect of exogenous calcitonin gene-related peptide (exCGRP) in newborn rats.. (1) To study the exET-1 induced PH: 100 newborn Wistar rats were randomly assigned into control group (group A, n = 10) and experiment groups (20 rats in each of groups B, C, D and E and 10 in group F). Thirty microl of normal saline and different concentrations of exET-1 in saline (ranged from 2 x 10(-6) mol/L to 10 x 10(-6) mol/L) were dripped into the rats' trachea through intubation for control group and the experiment groups, respectively. (2) To study the antagonizing effect of calcitonin gene-related peptide against endothelin: 50 rats were randomly assigned into control group (group D(1), n = 10) and experiment groups D(2), D(3), D(4) and D(5) (10 rats in each group), and were treated with 30 microl of normal saline as control and 4 x 10(-6) mol/L exET-1 via tracheal dripping. Twenty microl of exCGRP (concentrations ranged from 6.7 x 10(-8) mol/L to 6.7 x 10(-6) mol/L) were given by dripping to rats in groups D(3) to D(5) 30 minutes after the administration of exET-1. (3) The rats were sacrificed 3 hours after the first tracheal dripping and the gross anatomical and histological (HE staining) changes in lungs were observed.. (1) Following the treatment with exET-1, the rats showed cyanosis and dyspnea rapidly. The severity of respiratory symptoms varied in a dose dependent fashion with the concentrations of exET-1. The symptoms were relieved in the survived rats in about 30 minutes. The rats of all exET-1 treated groups presented with different degree of PH and group D (treated with 4 x 10(-6) mol/L of exET-1) had the highest incidence (diffuse PH 30%, focal PH 25%, spotty PH 25% and 80% in total), with a mortality of 20%. Rats in group E and F had lower incidence of PH (50% and 20%) but higher mortality (35% and 60%). (2) After the administration of different concentrations of exCGRP, the skin of the exET-1 treated rats turned ruddy rapidly with a significantly decreased incidence of PH and all the rats survived. The best protective effect was observed with the concentration of 6.7 x 10(-6) mol/L, and the incidence of PH was reduced to 20% (focal PH 10%, spotty PH 10%).. A significant increase of the endogenous ET-1 in hemorrhagic lung tissue caused by rewarming and reoxygenation following hypothermia and hypoxia had been confirmed. Administration of intratracheal exET-1 could induce pulmonary hemorrhage. This suggests that a significant increase of endogenous ET-1 in lung tissue may be one of the mechanisms in pathogenesis of PH caused by rewarming and reoxygenation following hypothermia and hypoxia. Endotracheal administration of exCGRP showed protective antagonizing effect against PH induced by exET-1. The authors speculate that the exCGRP has the potential to treat or even prevent PH caused by a significant increase of the endogenous ET-1.

Topics: Animals; Animals, Newborn; Calcitonin Gene-Related Peptide; Dose-Response Relationship, Drug; Endothelin-1; Female; Hemorrhage; Lung; Lung Diseases; Male; Random Allocation; Rats; Rats, Wistar

Endothelin-1 (ET-1) has fibrogenic and inflammatory properties. Its pathogenic role in pulmonary fibrosis and certain inflammatory airway diseases is now well known. Its production is, in part, triggered by infectious processes. Episodes of infection are suspected to be involved in the development of bronchiolitis obliterans syndrome (BOS), which is the main feature of chronic lung rejection and the major factor limiting the long-term survival of transplanted patients. We postulated that ET-1 is upregulated during infectious complications arising from the graft and that this could partly explain the remodeling of airway structures observed in BOS. We, therefore, set up this study to assess ET-1 expression in relation to complications of the graft in human lung transplant recipients.. ET-1 mRNA was quantified by reverse transcription-competitive polymerase chain reaction in cells from 119 samples of bronchoalveolar lavage (BAL) fluid from 17 lung transplant recipients. ET-1 and big ET-1 proteins were assessed in BAL cell culture supernatants by enzyme immunoassay. Transbronchial biopsies (n=21) were stained immunohistochemically for ET-1 receptors.. Episodes of bacterial infection strongly correlated with increased ET-1 mRNA and protein expression. ET-1 receptors were also upregulated during these episodes, especially on endothelial and smooth muscle cells. Five of the seven patients with the highest ET-1 levels subsequently developed BOS.. These results raise the possibility that ET-1, part of whose production is triggered by infectious postgraft complications, might play a role in the development of BOS through its potential effects on airway remodeling.

Topics: Adult; Bacterial Infections; Bronchi; Bronchiolitis Obliterans; Bronchoalveolar Lavage Fluid; Endothelin-1; Female; Humans; Lung Diseases; Lung Transplantation; Male; Receptor, Endothelin A; Receptors, Endothelin; RNA, Messenger; Tissue Distribution; Up-Regulation

Sarcoidosis is a chronic systemic disease, characterized by an imbalance of immunity processes and the presence of granuloma. Endothelin-1, a new vasoactive and bronchoconstrictive peptide, is a powerful mitogen for smooth muscle cells and fibroblasts and plays a role in the inflammation state. We postulate that endothelin-1 has a role in sarcoidosis.. We studied the behaviour of circulating levels of endothelin-1 in 20 patients with sarcoidosis and its correlation with some biochemical parameters of activity disease, such as erythrocyte sedimentation rate (ESR) and serum angiotensin-converting enzyme (SACE). We measured serum levels of ESR, SACE, calcium and plasma endothelin-1 levels in all patients at the beginning of the study and one again in 9 patients with clinical-biochemical remission of disease after steroid treatment.. In patients with sarcoidosis, circulating levels of endothelin-1, SACE and ESR were significantly higher (p<0.001) than those of healthy subjects. Moreover, in patients with pulmonary involvement, there was a significant statistical difference (p<0.001) between endothelin-1 levels and radiological stage compared to normal subjects. In the 9 patients with remission of disease, both endothelin-1 levels and parameters of activity disease normalized.. Our results seem to suggest that the increase of plasma endothelin-1 levels in active sarcoidosis can represent an expression of the endothelial dysfunction and reflect the picture of cellular activation.

Topics: Adrenal Cortex Hormones; Adult; Blood Sedimentation; Calcium; Endothelin-1; Endothelium, Vascular; Female; Humans; Lung Diseases; Male; Middle Aged; Peptidyl-Dipeptidase A; Sarcoidosis

Receptors for endothelin (ET)-1, a potent vasoconstrictor peptide, have two isoforms, i.e. ET(A) receptors and ET(B) receptors. We previously reported that an ET(A) receptor antagonist greatly ameliorated pulmonary hypertension due to congestive heart failure (CHF) in rats. In the present study of rats with pulmonary congestion secondary to CHF, we determined not only ET(A) receptor mRNA expression but also ET(B) receptor mRNA expression in the congestive lung because lung ET(B) receptors are reported to be important for the clearance of circulating ET-1. We also measured lung ET-1 and circulating ET-1 levels. The expression of ET(B) receptor mRNA in the lung was significantly lower in rats with CHF than in age-matched control rats, while the expression of ET(A) receptor mRNA did not differ between the two groups. The protein level of ET(B) receptor, determined by Western blot, in the lung was lower in the rats with CHF than in the control rats, while the protein level of ET(A) receptor did not differ between the two groups. The lung ET-1 level and plasma ET-1 level were significantly higher in the rats with CHF than in the controls by 1.4-fold and 5.3-fold, respectively. Thus, in the rats with CHF, ET-1 was increased to a much greater extent in plasma than in the lung. The present findings suggest that selective down-regulation of ET(B) receptor, but not ET(A) receptor, occurs in the congestive lung. Since lung ET(B) receptors play a role in the clearance of circulating ET-1, we propose that down-regulation of lung ET(B) receptors partly contributes to marked increases in circulating ET-1 and that increased ET-1 in the circulating plasma as well as in the lung is involved in the progression of pulmonary hypertension in CHF.

Topics: Animals; Blood Pressure; Disease Models, Animal; Down-Regulation; Endothelin-1; Heart Failure; Lung Diseases; Organ Size; Polymerase Chain Reaction; Rats; Receptor, Endothelin A; Receptor, Endothelin B; Receptors, Endothelin

This fifth international conference on ET serves to underline the rapid pace of development of our understanding of the very versatile ET system. On the one hand, the body uses ETs at several stages in embryonic development, in normal postnatal growth, and in cardiovascular homeostasis under healthy conditions. On the other hand, overwhelming evidence now exists that ET-1 plays important pathophysiological roles in conditions of decompensated vascular homeostasis. Indeed, in CHF this evidence is sufficient to justify the large-scale studies of morbidity and mortality needed to market ET antagonists as medicines. Other potentially important cardiovascular indications for ET antagonists are still emerging--including hypertension, stroke, subarachnoid haemorrhage and renal failure--and all are likely to be the subject of clinical trials over the next few years. As yet, there has been little work outside the cardiovascular and renal fields, but other areas, such as cancer treatment, may also prove promising. New molecules with increasing selectivity (ETA and ETB) continue to emerge and may be valuable. Inhibition of ECE-1 remains as an alternative approach and nonpeptide ECE inhibitors now exist. There appears to be a consensus that ETA blockade is beneficial in cardiovascular and renal disease. However, several strands of work presented at the meeting--the hypertensive salt-sensitive phenotype of rescued ETB knockout mice, the sustained and progressive hypertensive effects of ETB-selective antagonism in rats, ETB-mediated vasodilatation and natriuresis in dogs, and nitric oxide-dependent ETB-mediated vasodilatation in humans--all suggest that ETB-mediated vascular and renal responses may be protective. The development of selective ETA antagonists, therefore, now seems fully justified. In the future, direct comparisons in animal models, and patients, of ETA and ETA/B antagonists will be important in determining the value of additional ETB receptor blockade in individual diseases.

Topics: Animals; Animals, Genetically Modified; Aspartic Acid Endopeptidases; Cardiovascular Diseases; Endothelin Receptor Antagonists; Endothelin-1; Endothelin-Converting Enzymes; Humans; Kidney Diseases; Lung Diseases; Metalloendopeptidases; Mice; Mice, Knockout; Promoter Regions, Genetic

Overproduction and overexpression of endothelin-1 (ET-1) have been reported to contribute to the pathophysiology of pulmonary diseases, including pulmonary fibrosis, obliterative bronchiolitis, and primary pulmonary hypertension. To determine whether ET-1 contributes to the pathogenesis of pulmonary disease, we locally overexpressed ET-1 using an in vivo UV-inactivated hemagglutinating virus of Japan (HVJ) liposome-mediated gene transfer system. Plasmid DNA of ET-1 (pME18fc preproET-1) and high mobility group 1 (HMG1) protein were co-encapsulated in liposomes. Then the plasmid DNA and liposome complexes were introduced into the lung via the trachea in Wistar rats, using HVJ-mediated membrane fusion. Control animals received instillation of HVJ liposome with an empty cassette. Two weeks after in vivo transfection of the preproET-1 gene, hyperplastic connective tissue plaques were seen in the alveolar duct and small conducting airways, indicating histologically distinctive obliterative bronchiolitis. No histopathologic changes were seen in the control animals. These results suggested that local overexpression of ET-1 may play an important role in the pathogenesis of obliterative bronchiolitis.

Topics: Animals; Bronchiolitis Obliterans; DNA, Viral; Endothelin-1; Gene Transfer Techniques; Liposomes; Lung; Lung Diseases; Male; Rats; Rats, Wistar; Respirovirus; Respirovirus Infections

Our study was designed to elucidate the effects of tetramethylpyrazine (TMP), a Chinese medicine, on plasma endothelin-1 (ET-1) levels in dogs with acute pulmonary alveolar hypoxia. Anesthetized dogs were used under artificial ventilation with room air or a hypoxic gas mixture (10% O2 and 90% N2) (n = 10) for 60 min. Effects of TMP (80 mg/kg) were studied by i.v. injection of TMP before exposure to hypoxia (n = 8). Mean pulmonary arterial pressure (PAPm), systemic arterial pressure (SAPm), right atrial pressure (RAP), pulmonary capillary wedge pressure (PCWP), cardiac output (CO), and heart rate (HR) were measured. The pulmonary vascular resistance (PVR) was calculated by the equation of (PAPm-PCWP) x 8/CO. Plasma ET-1 levels were determined in the abdominal aorta and pulmonary artery by RIA. The effects of TMP on PAP and plasma ET-1 level were evaluated by using percent increase in PAPm and the change of Da-pET (delta ET) before and after hypoxia. Both PAPm and PVR were significantly elevated 5 min after acute hypoxia over a period of 60 min, whereas CO and PCWP did not change. Plasma ET-1 levels in the abdominal aorta and Da-pET showed a significant increase. Administration of TMP significantly decreased the hypoxia-induced increase in the PAPm, PVR, and delta ET. These results suggest that TMP could be a useful therapeutic agent in the treatment of pulmonary hypertension induced by acute hypoxia through decrease of plasma ET-1 levels.

Topics: Anesthesia, General; Animals; Blood Pressure; Dogs; Drugs, Chinese Herbal; Endothelin-1; Hemodynamics; Hypoxia; Lung Diseases; Pulmonary Alveoli; Pulmonary Circulation; Pyrazines; Vascular Resistance; Vasodilator Agents

To investigate the role of the endothelial-derived vasoactive mediator endothelin (ET-1) in the acute chest syndrome (ACS), we incubated bovine pulmonary artery endothelial cells (BPAEC) with red blood cells (equivalent to a hematocrit of 20%) and/or autologous plasma (1:10 dilution) from two patients during ACS and during routine clinic visits. Cellular RNA was analyzed for ET-1 transcripts by Northern analysis and ET-1 protein levels in BPAEC supernatants and in plasma measured by radioimmunoassay. ET-1 mRNA expression and protein levels increased in BPAEC exposed to plasma obtained during ACS; in contrast, exposure to plasma obtained during routine clinic visits did not alter BPAEC ET-1 mRNA expression or protein levels. Plasma ET-1 level was elevated during ACS, decreased during resolution, and remained slightly elevated during routine clinic visits. Plasma obtained from one patient 4 d prior to hospitalization for vasoocclusive crisis contained the highest ET-1 level and markedly increased BPAEC ET-1 mRNA expression and protein levels. In both patients, BPAEC ET-1 mRNA and protein expression in vitro and plasma ET-1 levels in vivo correlated with stage of disease and occurred in the absence of direct erythrocyte contact in vitro. These observations suggest that ET-1 production contributes to development of ACS.

Topics: Acute Disease; Adult; Anemia, Sickle Cell; Animals; Cattle; Endothelin-1; Female; Humans; Lung Diseases; Pulmonary Artery; RNA; RNA, Messenger