bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of enalapril and losartan on circulating adhesion molecules and monocyte chemotactic protein-1
Authors: JILMA B. , LI-SAW-HEE F.L. , WAGNER O.F. , BEEVERS D.G. , LIP G.Y.H.
Published: August 2015

At least four independent studies in different clinical settings showed that angiotensin-converting enzyme inhibitors (ACE-Is) such as enalapril effectively decrease plasma levels of circulating adhesion molecules (cAMs). To examine whether this effect may be mediated by the decreased action of angiotensin, we compared the effects of enalapril with the direct angiotensin-II antagonist, losartan, on plasma levels of cAMs, and monocyte chemotactic protein-1 (MCP-1). In a randomized trial, we recruited 32 untreated patients (19 male, aged 59±13years) with hypertension, who received either enalapril (mean dose 17mg/day) or losartan (mean dose 77mg/day) at equipotent doses. Enalapril decreased plasma levels of all cAMs after 8weeks of treatment: cE-selectin levels decreased by 13% (P = 0.007), intercellular adhesion molecule-1 (cICAM-1) by 15% (P = 0.002) and vascular cell adhesion molecule-1 (cVCAM-1) by 19% (P = 0.003). Similarly, enalapril decreased plasma levels of MCP-1 by 13% (P<0.001). Losartan did not significantly change cAM or MCP-1 plasma concentrations after 8weeks of treatment: cE-selectin levels decreased by 3%, cICAM-1 by 5%, cVCAM-1 by 8%, whereas MCP-1 increased by 2% (all P = NS; not significant). The enalapril effect on percentage changes of cVCAM-1 was significantly different from losartan (P = 0.0429). Eight weeks of antihypertensive treatment with enalapril but not losartan, significantly decreased plasma levels of cAMs and MCP-1 in hypertensive patients. The beneficial effects of ACE-Is on cAMs may have implications for atherogenesis and the reduction of cardiovascular events, which cannot be fully explained by their antihypertensive effects alone.
Expression of cholecystokinin in the duodenum of patients with coeliac disease: respective role of atrophy and lymphocytic infiltration
Authors: DEPREZ Pierre H. , SEMPOUX Christine , DE SAEGER Christine , RAHIER Jacques , MAINGUET Paul , PAUWELS Stanislas , GEUBEL André
Published: August 2015

Cholecystokinin (CCK) release after a standard test meal is decreased in coeliac patients. The aim of the study was to determine the origin of the CCK deficiency and the relationship between the distinctive types of mucosal lesions observed in coeliac disease and the number of duodenal CCK cells and their peptide and mRNA content. Duodenal biopsies were obtained in ten controls and nineteen coeliac patients [seven with atrophic mucosa, six with increased numbers of intraepithelial lymphocytes (IELs) and six with fully normalized mucosa]. Immunocytochemistry was performed with a CCK C-terminal-specific polyclonal antiserum. The CCK cells were counted and related to the epithelial area using a semi-automated image analyser. CCK content in mucosal extracts was determined by radioimmunoassay. mRNA was measured with a semi-quantitative reverse transcriptase–PCR method using specific CCK and ribosomal protein L19 (RPL19) primers. CCK tissue concentration and CCK mRNA were significantly reduced in patients with atrophic mucosa [12.2 (range 6.9–17.5) pmol/g; CCK/RPL19 ratio 0.64 (0.30–0.99)] compared with patients with normal mucosa [40.5 (30.4–50.7) pmol/g; CCK/RPL19 ratio 1.40 (0.41–2.40)] or controls [42.7 (18.2–67.2) pmol/g; CCK/RPL19 ratio 1.35 (1.09–1.62)]. A similar decrease was observed in patients with an excess of IELs, 13.9 (3.8–31.8) pmol/g and 0.86 (0.57–1.15) pmol/g respectively. The number of CCK cells was, however, similar in all groups. Duodenal CCK concentration and mRNA are decreased not only in the mucosa presenting atrophic changes but also when disease activity is limited to infiltration by IELs. Reduced expression of the CCK gene could therefore be related to suppressive factors induced by the inflammatory infiltrate.
New insights into the relationship between airway inflammation and asthma
Authors: WARDLAW A.J. , BRIGHTLING C.E. , GREEN R. , WOLTMANN G. , BRADDING P. , PAVORD I.D.
Published: August 2015

Asthma is a condition characterized by variable airflow obstruction, airway hyper-responsiveness (AHR) and airway inflammation which is usually, but not invariably, eosinophilic. Current thoughts on the pathogenesis of asthma are focused on the idea that it is caused by an inappropriate response of the specific immune system to harmless antigens, particularly allergens such as cat dander and house dust mite, that result in Th2-mediated chronic inflammation. However, the relationship between inflammation and asthma is complex, with no good correlation between the severity of inflammation, at least as measured by the number of eosinophils, and the severity of asthma. In addition, there are a number of conditions, such as eosinophilic bronchitis and allergic rhinitis, in which there is a Th2-mediated inflammatory response, but no asthma, as measured by variable airflow obstruction or AHR. Bronchoconstriction can also occur without obvious airway inflammation, and neutrophilic inflammation can in some cases be associated with asthma. When we compared the immunopathology of eosinophilic bronchitis and asthma, the only difference we observed was that, in asthma, the airway smooth muscle (ASM) was infiltrated by mast cells, suggesting that airway obstruction and AHR are due to an ASM mast cell myositis. This observation emphasizes that the features that characterize asthma, as opposed to bronchitis, are due to abnormalities in smooth muscle responsiveness, which could be intrinsic or acquired, and that inflammation is only relevant in that it leads to these abnormalities. It also emphasizes the importance of micro-localization as an organizing principle in physiological responses to airway inflammation. Thus, if inflammation is localized to the epithelium and lamina propria, then the symptoms of bronchitis (cough and mucus hypersecretion) result, and it is only if the ASM is involved–for reasons that remain to be established–that asthma occurs.
Effects of head-up tilting on baroreceptor control in subjects with different tolerances to orthostatic stress
Authors: COOPER V.L. , HAINSWORTH R.
Published: August 2015

During orthostatic stress, an increase in peripheral vascular resistance normally results in arterial blood pressure being well maintained, despite a decrease in cardiac output. The present study was undertaken to determine whether the sensitivity of the carotid baroreceptor reflex was increased during orthostatic stress and whether failure to develop this increase was associated with poor orthostatic tolerance. Three groups of subjects were studied: asymptomatic controls; patients investigated for suspected posturally related syncope but who had normal responses to an orthostatic stress test (normal patients); and patients who were shown to have low orthostatic tolerance (early fainters). We determined responses of R–R interval and forearm vascular resistance (mean arterial pressure/brachial artery velocity by Doppler ultrasonography) to the loading and unloading of carotid baroreceptors by application of pressures of -30 and +30mmHg to a chamber fitted over the neck. Responses were determined after 20min of supine rest and after 10min of head-up tilt at 60°. Responses of cardiac interval were not significantly different between the three groups, and they were not altered by the postural change. Vascular responses also did not differ between the groups during supine rest. However, in healthy volunteers and in normal patients, responses to both neck suction and pressure were significantly enhanced during head-up tilt. In controls, responses to suction were increased by tilt from 0.04±0.1 to -1.01±0.2%·mmHg-1 (means±S.E.M.; P<0.001) and those to neck pressure from -0.6±0.3 to -3.1±1.1%·mmHg-1 (P<0.05). In the normal patients, the corresponding changes were: during suction, from -0.2±0.1 to -0.7±0.1%·mmHg-1 (P<0.05); during pressure, from -0.7±0.1 to -1.5±0.3%·mmHg-1 (P<0.05). In contrast, in patients with low orthostatic tolerance, posture had no effect on the reflex (neck suction, from -0.3±0.1 to -0.3±0.1%·mmHg-1; neck pressure, from -1.0±0.3 to -0.9±0.2%·mmHg-1). We suggest that an increase in the sensitivity of the carotid baroreceptor/vascular resistance reflex may be important in the maintenance of blood pressure during orthostatic stress, and that failure of this to occur in patients with posturally related syncope may go some way towards explaining their poor orthostatic tolerance.
Hyperglycaemia suppresses the secretion of ghrelin, a novel growth-hormone-releasing peptide: responses to the intravenous and oral administration of glucose
Authors: NAKAGAWA Eiichiro , NAGAYA Noritoshi , OKUMURA Hiroyuki , ENOMOTO Mitsunobu , OYA Hideo , ONO Fumiaki , HOSODA Hiroshi , KOJIMA Masayasu , KANGAWA Kenji
Published: August 2015

Ghrelin is a novel growth hormone (GH)-releasing peptide, isolated from the stomach, which may also cause a positive energy balance by stimulating food intake and reducing fat utilization. However, whether glucose influences the release of ghrelin remains unknown. Accordingly, we examined circulating levels of ghrelin and GH in response to the intravenous or oral administration of 50g of glucose in eight healthy humans. After the administration of intravenous glucose (50g), the plasma ghrelin level decreased significantly from 127±9 to 98±9fmol/ml (P<0.01), associated with an increase in plasma glucose from 85±3 to 357±19mg/dl (P<0.01). Ingestion of 50g of glucose decreased the plasma ghrelin level significantly from 134±12 to 97±15fmol/ml (P<0.01), associated with an increase in plasma glucose from 93±3 to 166±10mg/dl (P<0.01). The decrease in the plasma ghrelin level lasted for more than 30min after recovery of the plasma glucose level. In conclusion, ghrelin secretion may be suppressed, at least in part, by an increased plasma glucose level in healthy humans.
Glutamine plays a role in superoxide production and the expression of p47phox, p22phox and gp91phox in rat neutrophils
Authors: PITHON-CURI Tania Cristina , LEVADA Adriana C. , LOPES Lúcia R. , DOI Sonia Q. , CURI Rui
Published: August 2015

The effect of glutamine on the activity of the NADPH oxidase complex from rat neutrophils was investigated. Superoxide anion (O2-) production was assessed: (1) by scintillation counting by using lucigenin, and (2) by reduction of cytochrome c over 10min. The effects of glutamine and PMA on the expression of the NADPH oxidase components p22phox, gp91phox and p47phox were also determined. Glutamine at 1 and 2mM increased O2- generation in the presence of PMA by 100% and 74% respectively, in neutrophils maintained previously for 3h in medium deprived of this amino acid. DON (6-diazo-5-oxo-l-norleucine), an inhibitor of phosphate-dependent glutaminase and thus of glutamine metabolism, caused a significant decrease in O2- production by neutrophils stimulated with PMA both in the absence (44%) and in the presence (66%) of glutamine. PMA markedly increased the expression of gp91phox, p22phox and p47phox mRNAs. Glutamine (2mM) increased the expression of these three proteins both in the absence and in the presence of PMA. We postulate that glutamine leads to O2- production in neutrophils, probably via the generation of ATP and regulation of the expression of components of NADPH oxidase.
Lipolysis generates platelet dysfunction after in vivo heparin administration
Authors: MURIITHI Elijah W. , BELCHER Philip R. , DAY Stephen P. , CHAUDHRY Mubarak A. , CASLAKE Muriel J. , WHEATLEY David J.
Published: August 2015

Heparin, when administered to patients undergoing operations using cardiopulmonary bypass, induces plasma changes that gradually impair platelet macroaggregation, but heparinization of whole blood in vitro does not have this effect. The plasma changes induced by heparin in vivo continue to progress in whole blood ex vivo. Heparin releases several endothelial proteins, including lipoprotein lipase, hepatic lipase, platelet factor-4 and superoxide dismutase. These enzymes, which remain active in plasma ex vivo, may impair platelet macroaggregation after in vivo heparinization and during cardiopulmonary bypass. In the present study, proteins were added in vitro to hirudin (200units·ml-1)-anticoagulated blood from healthy volunteers, and the platelet macroaggregatory responses to ex vivo stimulation with collagen (0.6μg·ml-1) were assessed by whole-blood impedance aggregometry. Over a 4h period, human lipoprotein lipase and human hepatic lipase reduced the platelet macroaggregatory response from 17.0±2.3 to 1.5±1.3 and 1.2±0.6Ω respectively (means±S.D.) (both P<0.01; n = 6). Other lipoprotein lipases also impaired platelet macroaggregation, but platelet factor-4 and superoxide dismutase did not. Platelet macroaggregation showed an inverse linear correlation with plasma concentrations of non-esterified fatty acids (r2 = 0.69; two-sided P<0.0001; n = 8), suggesting that heparin-induced lipolysis inhibits platelet macroaggregation. Lipoprotein degradation products may cause this inhibition by interfering with eicosanoids and other lipid mediators of metabolism.
Chylomicron-remnant-like particles inhibit receptor-mediated endothelium-dependent vasorelaxation in pig coronary arteries
Authors: GOULTER Andrew B. , AVELLA Michael A. , ELLIOTT Jonathan , BOTHAM Kathleen M.
Published: August 2015

The influence of native and oxidized chylomicron-remnant-like particles (CMR-LPs) on endothelium-dependent relaxation in pig coronary arteries was studied. Artificial lipid particles of a size and lipid composition resembling chylomicron remnants and containing pig apolipoprotein E were used to investigate the effects of chylomicron remnants on the relaxation of isolated segments of pig coronary arteries in response to three endothelium dilators: 5-hydroxytryptamine (5-HT), bradykinin and the calcium ionophore A23187. CMR-LPs caused significant inhibition of the maximum relaxation response of the vessels to 5-HT, but not that to bradykinin or A23187 (P<0.05). In contrast, CMR-LPs that had been oxidized by incubation with 10μM CuSO4 (oxidized CMR-LPs) were found to significantly reduce maximal relaxation to bradykinin by 13% (P<0.05) and to reduce the sensitivity of the tissue to A23187 by 1.7-fold (P<0.05). In experiments in which either the L-arginine/nitric oxide (NO) pathway or the endothelium-derived hyperpolarizing factor (EDHF) pathway was selectively inhibited, leaving the other intact, the inhibitory effect of oxidized CMR-LPs was observed only in vessels in which the L-arginine/NO-mediated pathway was operative. Furthermore, the oxidized particles had no inhibitory effect on the relaxation of the vessel segments to the non-endothelium-dependent agonists S-nitro-N-acetylpenicillamine, 5'-(N-ethylcarboxamido)adenosine or pinacidil. These results demonstrate that CMR-LPs inhibit vascular relaxation in pig coronary arteries by an endothelium-dependent mechanism involving the L-arginine/NO pathway, but not the EDHF pathway, and provide evidence in support of a role for chylomicron remnants in the endothelial dysfunction associated with hypercholesterolaemia and atherogenesis.
Natriuretic effect of caffeine: assessment of segmental sodium reabsorption in humans
Authors: SHIRLEY D.G. , WALTER S.J. , NOORMOHAMED F.H.
Published: August 2015

In order to assess the intrarenal mechanisms responsible for the natriuretic action of caffeine, the renal clearances of 51Cr-EDTA [used as a measure of glomerular filtration rate (GFR)] and lithium (used as an index of end-proximal fluid delivery) were measured in eight healthy males before (control period) and immediately after (experimental period) a 400mg oral dose of caffeine (given over 90min) or placebo. In caffeine-treated subjects, the fractional excretion of sodium rose from 1.00±0.25% in the control period to 1.47±0.18% in the experimental period, while corresponding values on the placebo day were 1.04±0.16% and 0.70±0.07% respectively. GFR was unchanged following either caffeine or placebo. When compared with the placebo day, caffeine caused increases in lithium clearance (experimental period values: caffeine, 37±1ml/min; placebo, 28±2ml/min; P<0.001), the fractional excretion of lithium (caffeine, 34±1%; placebo, 26±2%; P<0.001) and the sodium/lithium clearance ratio (used as an index of the fraction of sodium delivered to the distal nephron that escapes reabsorption therein: caffeine, 4.4±0.3%; placebo, 2.8±0.2%; P<0.001). These results suggest that reduced fractional sodium reabsorption in both the proximal tubule and the distal nephron contributes to the acute natriuretic effect of caffeine. The data also confirm the importance of controlling caffeine intake when investigating renal function using lithium clearance.
Albumin synthesis in humans increases immediately following the administration of endotoxin
Authors: BARLE Hans , JANUSZKIEWICZ Anna , HÅLLSTRÖM Lars , ESSÉN Pia , MCNURLAN Margaret A. , GARLICK Peter J. , WERNERMAN Jan
Published: August 2015

In order to investigate the immediate (i.e. within 3h) response of albumin synthesis to the administration of endotoxin, as a model of a moderate and well controlled catabolic insult, two measurements employing L-[2H5]phenylalanine were performed in 16 volunteers. One group (n = 8) received an intravenous injection of endotoxin (4ng/kg; lot EC-6) immediately after the first measurement of albumin synthesis, whereas the other group received saline. A second measurement was initiated 1h later. In the endotoxin group, the fractional synthesis rate of albumin was 6.9±0.6%/day (mean±S.D.) in the first measurement. In the second measurement, a significant increase was observed (9.6±1.2%/day; P<0.001). The corresponding values in the control group were were 6.6±0.6%/day and 7.0±0.6%/day respectively (not significant compared with first measurement and P<0.001 compared with the second measurement in the endotoxin group). The absolute synthesis rates of albumin were 148±35 and 201±49mg·kg-1·day-1 before and after endotoxin (P<0.01). In the control group, the corresponding values were 131±21 and 132±20mg·kg-1·day-1 (not significant compared with the first measurement and P<0.01 compared with the second measurement in the endotoxin group). In conclusion, these results indicate that albumin synthesis increases in the very early phase after a catabolic insult, as represented by the administration of endotoxin.
Cholesteryl ester transfer protein inhibitor (JTT-705) and the development of atherosclerosis in rabbits with severe hypercholesterolaemia
Authors: HUANG Zhiping , INAZU Akihiro , NOHARA Atsushi , HIGASHIKATA Toshinori , MABUCHI Hiroshi
Published: August 2015

Cholesteryl ester transfer protein (CETP) is a major determinant of plasma levels of high-density lipoprotein-cholesterol (HDL-C) in humans. The anti-atherogenic effect of lowering CETP levels is dependent not only on HDL-C levels but also on a metabolic background of increased low-density lipoprotein or very-low-density lipoprotein. Here we investigated the effects of JTT-705, a chemical inhibitor of CETP, on the development of atherosclerosis in Japanese white rabbits fed on a high cholesterol diet. After 4 weeks on a diet of 0.25% cholesterol-containing chow, 100mg/kg (low dose) or 300mg/kg (high dose) JTT-705 was given, and the animals were monitored at weeks 0, 4, 8 and 12. Aortic atherosclerotic lesions were determined at the end of this period. JTT-705 induced a significant increase in HDL-C in the high-dose group [from 21±3 to 50±7mg/dl (mean±S.E.M.); P<0.0001] compared with the control group (from 21±2 to 27±2mg/dl). The atheromatous area was 60±9% in the high-dose group and 58±9% in the control group. Moreover, correlation analysis showed that triacylglycerol and non-HDL-C levels had a direct relationship with the development of atherosclerosis, but CETP activity and HDL-C levels did not. Thus the CETP inhibitor JTT-705 alone did not have an anti-atherogenic effect in our rabbit model, of severe hypercholesterolaemia suggesting a relatively minor effect of HDL-elevating therapy as compared with decreases in non-HDL-C (or triacylglycerol) levels in patients with severe hypercholesterolaemia, such as familial hypercholesterolaemia.
Transplantation of embryonic kidneys
Authors: HAMMERMAN Marc R.
Published: August 2015

The number of kidney allotransplants performed per year is limited by the availability of human donor organs. Xenotransplantation of a vascularized organ, such as the kidney, as an alternative to allotransplantation presents formidable immunological challenges. One novel solution to this conundrum is to use embryonic kidneys taken from animal donors early during organogenesis when metanephroi can be transplanted in ‘cellular’ form. We and others have shown that developing embryonic kidneys (metanephroi) transplanted into the omentum of animal hosts undergo differentiation and growth in situ, become vascularized by blood vessels of host origin and exhibit excretory function. Metanephroi can be stored for up to 3 days in vitro prior to transplantation with no impairment in growth or function post-implantation. Metanephroi can be transplanted across both concordant (rat to mouse) and highly disparate/discordant (pig to rodent) xenogeneic barriers. This review summarizes experimental data relating to the transplantation of embryonic kidneys.
Time course of gene expression in rat experimental autoimmune myocarditis
Authors: HANAWA Haruo , ABE Satoru , HAYASHI Manabu , YOSHIDA Tsuyoshi , YOSHIDA Kaori , SHIONO Takaaki , FUSE Koichi , ITO Masahiro , TACHIKAWA Hitoshi , KASHIMURA Takeshi , OKURA Yuji , KATO Kiminori , KODAMA Makoto , MARUYAMA Seitaro , YAMAMOTO Tadashi , AIZAWA Yoshifusa
Published: August 2015

Genetic responses that characterize experimental autoimmune myocarditis (EAM) have not yet been determined. To investigate gene expression in the myocardium of EAM, absolute copy numbers of 44 mRNA species [calcium-handling proteins, contractile proteins, natriuretic peptides (NPs), cytokines, chemokines, growth factors, renin–angiotensin–aldosterone (RAA) system, endothelins (ETs) and extracellular matrix] in synthesized cDNA from a fixed quantity of total heart RNA were assessed using real-time reverse-transcriptase PCR at days 0, 14, 21 and 28 after immunization. α-Cardiac myosin showed a 26.3-fold decrease and β-cardiac myosin a 3.75-fold increase at day 14. Atrial NP and brain NP increased 47.7- and 6.35-fold at days 21 and 14 respectively. Angiotensin II type 1 receptor, angiotensin-converting enzyme and ET1 increased 22.3-fold at day 21, 6.30-fold at day 21 and 16.8-fold at day 14 respectively. Aldosterone receptor decreased 2.15-fold at day 14, but aldosterone synthetase was detected only at days 14 and 21. Interleukin (IL)-2, IL-10, interferon-γ and monocyte chemo-attractant protein-1 increased 9.08-fold at day 14, 398-fold at day 21, 43.1-fold at day 14 and 142-fold at day 14 respectively. Collagen type 3, collagen type 1 and fibronectin increased 34.6-, 1.74- and 44.4-fold respectively at day 21. Interestingly, osteopontin showed a 4540-fold increase and it was the highest mRNA of all at day 14. An isoform of cardiac myosin and NP are dramatically changed in EAM. RAA system and ET expressions are changed differently during the EAM time course. Cytokine, chemokine and extracellular matrix greatly increase and, in particular, large numbers of osteopontin mRNA are expressed in early EAM.
Increased systolic blood pressure in rats induced by a maternal low-protein diet is reversed by dietary supplementation with glycine
Authors: JACKSON Alan A. , DUNN Rebecca L. , MARCHAND Michael C. , LANGLEY-EVANS Simon C.
Published: August 2015

When rat dams consume a diet low in protein during pregnancy, their offspring develop high blood pressure. On a low-protein diet, the endogenous formation of the amino acid glycine is thought to become constrained. Glycine may become conditionally essential, as its rate of endogenous formation is inadequate to meet metabolic needs, and may be limiting for the normal development of the fetus. In the present study, five groups of Wistar rats were provided during pregnancy with one of five diets: a control diet containing 18% (w/w) casein (CON), a low-protein diet containing 9% casein (MLP), or the low-protein diet supplemented with 3% glycine (MLPG), alanine (MLPA) or urea (MLPU). The offspring were weaned on to standard laboratory chow, and blood pressure was measured at 4 weeks of age. Blood pressure was significantly increased in the MLP, MLPA and MLPU groups compared with the CON group, but for the MLPG group blood pressure was not significantly different from CON. Compared with the CON group, body weight was significantly reduced for the MLP, MLPA and MLPG groups, but for the MLPU group body weight was not different from CON. These data show that different forms of non-essential dietary nitrogen, when consumed during pregnancy, exert different effects upon the growth and function of the offspring. The availability of glycine appears to be of critical importance for normal cardiovascular development.
The inhaled ETA receptor antagonist LU-135252 acts as a selective pulmonary vasodilator
Authors: DEJA Maria , WOLF Steffen , BUSCH Thilo , PETERSEN Bodil , JAGHZIES Ursel , BOEMKE Willehad , KAISERS Udo
Published: August 2015

To investigate the hypothesis that the inhaled ETA receptor antagonist LU-135252 acts as selective pulmonary vasodilator, we compared inhaled LU-135252 and inhaled nitric oxide (iNO) in an experimental model of acute lung injury (ALI), in a prospective, randomized, controlled animal study. A total of 30 anaesthetized, tracheotomized and mechanically ventilated pigs underwent induction of ALI by repeated saline washout of surfactant. The animals were then randomly assigned to receive the nebulized ETA receptor antagonist LU-135252 (0.3mg·kg-1, inhaled over 20min; ETA-A group; n = 10), inhaled NO (30p.p.m. continuously; iNO group; n = 10) or nebulized saline buffer (5ml inhaled over 20min; control group; n = 10). Measurements of pulmonary gas exchange and haemodynamics were performed hourly over a 4h period after induction of ALI. In the ETA-A group, the arterial oxygen tension (Pao2) increased from 58±3 to 377±39mmHg at 4h after intervention, while the intrapulmonary shunt (QS/QT) decreased from 53±4% to 18±2% (P<0.01 compared with controls). In the iNO group, PaO2 increased from 62±4 to 224±48mmHg, and QS/QT decreased from 47±2% to 27±5%, at 4h after induction of ALI (P<0.05 compared with controls). In the ETA-A and iNO groups, the increase in mean pulmonary artery pressure was significantly attenuated compared with controls (ETA-A group, 14±4%; iNO group, 6±4%; values at 4h; P<0.01compared with controls). In contrast, there were no significant differences in changes of mean arterial pressure and cardiac output between groups. Thus, in this experimental model of ALI, both inhaled LU-135252 and iNO significantly improved gas exchange and prevented an increase in mean pulmonary artery pressure, without significant systemic effects, when compared with controls. Our results indicate the occurrence of selective pulmonary vasodilation in both treatment groups.
ETA receptor blockade protects the small intestine against ischaemia/reperfusion injury in dogs via an enhancement of antioxidant defences
Authors: ANDRÁSI Terézia B. , KÉKESI Violetta , BLÁZOVICS Anna , DÓBI István , SZABÂ Gábor , JUHÁSZ-NAGY Alexander
Published: August 2015

The aim of the present study was to determine whether the ETA receptor antagonist LU135252 can protect the mesenterium against ischaemia/reperfusion (I/R) damage. Direct occlusion of the superior mesenteric artery was performed for 30min in two groups of dogs. Declamping was followed by 90min of reperfusion. Mesenteric release of ET-1 was studied in series 1 (n = 6). In series 2, 5min before cross-clamping, the treated group (n = 7) received an intravenous bolus of LU135252 (5mg/kg), whereas the control group (n = 6) was given vehicle. Mean arterial blood pressure and mesenteric blood flow were recorded. Mesenteric venous and systemic arterial serum lactate and glucose, plasma creatine kinase and free radical concentrations were determined at 15min intervals. Ischaemia for 30min induced a significant increase (P<0.05) in mesenteric ET-1 release (1594±526pg/min, compared with 343±258pg/min at baseline), which had returned to baseline after 20min of reperfusion. LU135252 administration significantly decreased mesenteric blood flow during ischaemia (204±23%) compared with controls (320±34%, P<0.05). In contrast, mesenteric blood flow was higher in the treated group (120±19% compared with 82±7%; P<0.05) after 90min of reperfusion. Mesenteric lactate production was reduced by ETA antagonist administration under ischaemia (0.77±0.02mmol/l) compared with controls (1.36±0.04mmol/l; P<0.01). Lower levels of venous creatine kinase were present in the treated group during ischaemia as well as after reperfusion (120±7% compared with 150±16%; P<0.01). Administration of LU135252 also improved the total scavenger capacity of the mesenteric bed during ischaemia [(15.9±3.9)×106 compared with (6.4±3.6)×106 relative light units; P<0.05] and early reperfusion [(8.7±3.1)×106 compared with (1.1±2.9)×106 relative light units]. Thus ET-1 is involved in I/R-induced disturbances in the intestine. LU135252 seems to counteract these changes, in part by increasing the antioxidant capacity of the mesenterium.
Sequence analysis and expression of the mouse full-length vasoactive intestinal contractor/endothelin-2 gene (EDN2): comparison with the endothelin-1 gene (EDN1)
Authors: SAIDA Kaname , KOMETANI Naoko , UCHIDE Tsuyoshi , MITSUI Youji
Published: August 2015

Vasoactive intestinal contractor (VIC)/endothelin-2 (ET2) is a vasoactive peptide hormone comprising 21 amino acids. The complete nucleotide sequence of the full-length gene encoding preproVIC (PPVIC) was determined. The PPVIC gene contains five exons that span 6kb and shows a duplication on exons 2 and 3, coding for the VIC and VIC-like peptides respectively. Similarities between the genomic organization of the PPVIC/preproET2 and preproendothelin-1 genes suggest that the two are distantly related. PPVIC gene expression was observed in foetal and adult mouse intestine. The expression level in adults was approx. 10-fold higher than in the foetus, suggesting an involvement of VIC in intestinal development.
Endothelin signalling and regulation of protein kinases in glomerular mesangial cells
Authors: SOROKIN Andrey , FOSCHI Marco , DUNN Michael J.
Published: August 2015

The molecular mechanisms of endothelin (ET)-dependent activation of extracellular signal-regulated kinase (ERK)and p38 mitogen-activated protein (MAP) kinase were studied in rat and human renal glomerular mesangial cells. ET-1 induced a rapid and transient activation of Ras in renal mesangial cells, which was dependent upon the formation of the Shc/Grb2/Sos1 signalling complex and resulted in transient ERK activation. We have observed that Pyk2, a calcium-dependent cytoplasmic tyrosine kinase, was expressed in human renal mesangial cells and was tyrosine phosphorylated after ET-1 treatment. ET-1-induced activation of p38 MAPK pathway (but not ERK pathway) was inhibited in human and in rat glomerular mesangial cells expressing dominant-negative form of Pyk2, suggesting the engagement of Pyk2 in ET-1-mediated activation of p38 MAP kinase cascade. Contractive responsiveness of renal mesangial cells was shown to depend on activation of the p38 MAP kinases. Thus, p38 MAP kinase stimulation could perhaps partially account for ET-1 contractive properties, whereas ET-1-induced cell proliferation occurs primarily via Ras-dependent activation of the ERK.
Differential effects of endothelin-1 on isolated working rat hearts before and after ischaemia and reperfusion
Authors: GOODWIN Andrew T. , AMRANI Mohamed , GRAY Caroline C. , JAYAKUMAR Jay , MARCHBANK Adrian J. , YACOUB Magdi H.
Published: August 2015

Endothelin (ET) may have both detrimental (reduced coronary flow) and beneficial effects (positive inotrope, reduced arrhythmogenesis) following ischaemia. We examined the effects of ET on cardiac function during reperfusion following prolonged hypothermic cardioplegic arrest in a protocol mimicking cardiac transplantation. Isolated working rat hearts were perfused with Krebs buffer to which increasing concentrations of ET-1 or sarafotoxin S6c had been added. Identical experiments were performed after 4h of cardioplegic arrest at 4°C. Under pre-ischaemic conditions ET-1 caused a dose-dependent decrease in cardiac function compared with controls. In contrast, following ischaemia low doses of ET-1 (10-10 M) caused a significant and beneficial increase in cardiac output (109.1% versus 81.3%), dP/dt i.e. the rate of change of pressure with time (94.7% versus 75.6%) and stroke volume (100.3% versus 77.5%) compared with controls (P<0.05). At higher doses of ET-1 there was a detrimental effect on cardiac output, dP/dt and stroke volume similar to that seen prior to ischaemia. Sarafotoxin S6c had no significant effect pre or post ischaemia on any of the parameters measured compared with controls (P = not significant). ET-1 at low concentrations during reperfusion can improve the recovery of cardiac function mediated via ETA receptors. ET may play an important physiological role in the recovery of cardiac function following prolonged ischaemia.
Endothelin-1-induced elevations in purine metabolite concentrations — autoregulatory protection in the canine pericardium?
Authors: ZIMA Endre , KÉKESI Violetta , NAGY Andrea , LOSONCZI László , TOMA Ildikó , SOÓS Pál , Barát Erzsébet , HUSZÁR Éva , MERKELY Béla , HORKAY Ferenc , Juhász-Nagy Alexander
Published: August 2015

Pericardial fluid accumulates the cardioprotective purine metabolites, as well as the endogenous vasoconstrictor agent endothelin-1 (ET-1). The aim of the present study was to characterize the pericardial concentrations of the purine metabolites adenosine, inosine and hypoxanthine before and after intrapericardial administration of ET-1 to the in situ heart. The closed pericardial sac of anaesthetized dogs (n = 9) was cannulated for ET-1 administration and for obtaining native pericardial fluid and control pericardial infusate samples (C1 and C2), as well as consecutive pericardial infusate samples (samples I, II and III) obtained 15min after intrapericardial administration of 150pmol/kg ET-1. In an additional five dogs, using the same protocol, ventricular epicardial and endocardial monophasic action potential recordings were performed to assess local ischaemic electrophysiological changes. Significant elevations of pericardial purine metabolite concentrations (measured by HPLC) were found in sample II compared with sample C2: adenosine, 4.5±1.7 compared with 0.5±0.1µM (P<0.05); inosine, 18.3±2.8 compared with 0.9±0.2µM (P<0.001); hypoxanthine, 38.1±8.0 compared with 13.4±2.6µM (P<0.01). Systemic blood pressure, left ventricular pressure and contractility, and systemic plasma levels of the purine metabolites remained unchanged during the ET-1 effect, while significant ECG ST elevations (STmax 0.68±0.01mV; P<0.001) were observed. In the five dogs analysed electrophysiologically, the left ventricular epicardial monophasic action potential duration and upstroke velocity decreased significantly at time point II compared with C2, while the endocardial monophasic action potential duration and upstroke velocity did not show ischaemia-related changes. The results suggest that intrapericardial administration of ET-1 induces subepicardial ischaemia, with parallel activation of coronary metabolic adaptive and cardiac self-protective mechanisms in the epimyocardial layer of the heart.
Endothelin-1 promotes proteolytic activity of ovarian carcinoma
Authors: ROSANÒ Laura , SALANI Debora , DI CASTRO Valeriana , SPINELLA Francesca , NATALI Pier Giorgio , BAGNATO Anna
Published: August 2015

Endothelin-1 (ET-1) is a potent mitogenic and angiogenic factor for ovarian carcinoma cell lines, which acts selectively through the ETA receptor (ETAR). A previous study demonstrated that ET-1 is present at high concentrations in ovarian cancer ascites, indicating a direct role in the progression and metastasis of ovarian carcinoma. In this study, we investigated whether ET-1 could induce production and activation of tumour-associated proteinases in ovarian carcinoma cells. As demonstrated by ELISA, we found that the secretion of matrix metalloproteinase (MMP)-2 and MMP-9, urokinase-type plasminogen activator and plasminogen activator inhibitor type-1 and -2 was upregulated by ET-1 in a dose-dependent manner in the HEY cell line. In addition, the MMPs in ET-1-treated cells are consistently active, as shown by MMP gelatinase activity assay. Finally, we demonstrated that BQ-123, an antagonist of ETAR, inhibited the ET-1-induced tumour protease secretion and activity, suggesting that ET-1/ETAR may play an important role in the progression and metastasis of ovarian carcinoma, activating multiple proteinase cascades.
Coronary effects of endothelin-1 during acute hypertension in anaesthetized goats
Authors: FERNÁNDEZ Nuria , ANGELES MARTÍNEZ María , GARCÍA-VILLALÓN Angel Luis , MONGE Luis , DIÉGUEZ Godofredo
Published: August 2015

The coronary effects of endothelin-1 (ET-1) during acute hypertension were examined in anesthetized goats, where the left circumflex coronary artery flow was electromagnetically measured and hypertension was induced by constriction of the thoracic aorta. In six non-treated goats, aortic constriction increased arterial pressure (mean arterial pressure = 128±5mmHg) and coronary flow (by 34%) without changing coronary vascular conductance. In this case, ET-1 (0.01–0.3nmol) when injected intracoronarily, decreased coronary vascular conductance, which was similar in hypertension and in normotension. In eight NG-nitro-L-arginine methyl ester-treated goats, aortic constriction increased arterial pressure (mean arterial pressure = 131±5mmHg) and coronary flow (by 26%) and decreased coronary vascular conductance (by 17%). In this case, ET-1 (0.01–0.3nmol) also decreased coronary vascular conductance, which was similar in NG-nitro-L-arginine methyl ester-treated hypertension that observed in normotension. Therefore, acute hypertension attenuates the coronary vasoconstriction caused by ET-1, and this attenuation might be related to mechanisms other than changes in NO release.
Pathophysiological roles of Ca2+ overload via the Na+/Ca2+ exchanger and endothelin-1 overproduction in ischaemia/reperfusion-induced acute renal failure
Authors: MATSUMURA Yasuo , YAMASHITA Junji , KITA Satomi , IWAMOTO Takahiro , OGATA Masaya , TAKAOKA Masanori , WAKIMOTO Koji , SHIGEKAWA Munekazu , KOMURO Issei
Published: August 2015

Using Na+/Ca2+ exchanger (NCX1)-deficient mice, the pathophysiological role of Ca2+ overload via the reverse mode of the Na+/Ca2+ exchanger in ischaemia/reperfusion-induced renal injury was investigated. Since NCX1-/- homozygous mice die of heart failure before birth, we utilized NCX1+/- heterozygous mice. The ischaemia/reperfusion-induced renal dysfunction in heterozygous mice were significantly attenuated compared with cases in wild-type mice. Also, histological renal damage such as tubular necrosis and proteinaceous casts in tubuli in heterozygous mice were much less than that in wild-type mice. Ca2+ deposition in necrotic tubular epithelium was observed more markedly in wild-type than in heterozygous mice. The increase in renal endothelin-1 (ET-1) content was significantly greater in wild-type than in heterozygous mice, and this reflected the difference in immunohistochemical ET-1 localization in necrotic tubular epithelium. We conclude that Ca2+ overload via the reverse-mode of Na+/Ca2+ exchange, followed by renal ET-1 overproduction, plays an important role in the pathogenesis of ischaemia/reperfusion-induced acute renal failure.
Effect of the novel endothelin(A) receptor antagonist LU 208075 on contraction and relaxation of isolated rat basilar artery
Authors: VATTER Hartmut , ZIMMERMANN Michael , JUNG Carla , WEYRAUCH Edda , LANG Josef , SEIFERT Volker
Published: August 2015

Increased levels of endothelin (ET)-1 and bigET-1 may be responsible for enhanced cerebroarterial resistance under pathologic conditions. Therefore, the effect of LU 208075, a novel ET(A)-selective receptor antagonist was determined. The aim of the study was to investigate in vitro the inhibitory effect of LU 208075 on ET-1 and bigET-1 induced contraction and relaxation in rat basilar artery segments. Segments with (E+) and without (E-) endothelium were prepared for the measurement of isometric force. Concentration–effect curves (CECs) were constructed by cumulative application of ET-1 or bigET-1. The shift of the CECs in the presence of LU 208075 against the control curve was determined. Relaxation was investigated on precontracted segments, calculated in percentage decrease of precontraction and compared by the pD2 and Emax. ET-1 and bigET-1 induced contraction was dose dependently inhibited by LU 208075. Shifts of the CECs in the presence of LU 208075 (10-6M and 10-5M) were for ET-1 (1) in E+: 4.4 and 19.7; (2) in E-: 8.1 and 60.4 and for bigET-1 (3) in E+: 10.8 and (4) in E-: 26.0 respectively. LU 208075 (10-5M) completely inhibited bigET-1-induced contraction. Relaxation by ET-1 or bigE-1 was only observed in the presence of LU 208075. CECs were shifted to the right by LU 208075 (10-5 M) by a factor of 24 (ET-1) and 4.5 (bigET-1). Emax values were 45±18% and 51±15% (ET-1; in the presence of 10-5 and 10-6 M LU 208075 respectively), and 56±20% and 49±17% (bigET-1; in the presence of 10-5 and 10-6 M LU 208075 respectively). The data suggests a competitive ET(A)-receptor inhibition by LU 208075. The enhanced inhibitory effect on bigET-1-induced contraction could indicate an additional inhibitory effect on endothelin-converting enzyme activity. The pronounced effect on E-vessels and the inhibition of relaxation may suggest an ET(B) receptor affinity.
Endothelin system in normal and hypertensive pregnancy
Authors: SLOWINSKI Torsten , NEUMAYER Hans-H. , STOLZE Thomas , GOSSING Gabriele , HALLE Horst , HOCHER Berthold
Published: August 2015

Pre-eclampsia complicates approximately 5–7% of pregnancies and it may be deleterious to both maternal and fetal health. In a prospective study, we investigated plasma endothelin (ET)-1 concentration within the 24th and 36th gestational week in non-smoking pregnant women. Thirty women fulfilled the criteria for the diagnosis of pre-eclampsia according to the American College of Obstetricians and Gynaecologists: de novo arterial hypertension after the 20th gestational week in at least two separate measurements and proteinuria of more than 300mg/l in a random specimen. For comparison, we analysed blood samples from 125 non-pre-eclamptic pregnant women. ET-1 concentrations were higher in pre-eclamptic pregnancies at both time points (mean±S.D.: 1.07±2.00 versus 0.54±0.56pg/ml, P = 0.045 at 24th week; 0.75±1.20 versus 0.44±0.45pg/ml, P = 0.023 at 36th week). Receiver operating characteristic (ROC) curves revealed a significant interaction between ET-1 plasma concentrations at the 36th week and the diagnosis of pre-eclampsia [area under the curve (AUC)±S.E.M.: 0.657±0.049, P = 0.008] and a cut-off value at 0.30pg/ml. Multivariate analysis showed a 4.6-fold higher chance (95% confidence interval: 1.7–12.1, P = 0.002) for the diagnosis of pre-eclampsia in pregnant women with ET-1 plasma concentration higher than 0.30pg/ml at the 36th week. Interaction between ET-1 plasma concentration at the 24th week and diagnosis of pre-eclampsia was not significant in ROC curve analysis (AUC±S.E.M.: 0.594±0.071, P = 0.278). Interestingly, we found a strong positive correlation between ET-1 concentration in the 24th and 36th week in linear regression analysis in pre-eclamptic (r = 0.99, P<0.001) and non-pre-eclamptic pregnancies (r = 0.61, P<0.001) with a slightly, non-significant decrease from the 24th to 36th week (for group means see above), indicating individual plasma ET-1 levels even in non-pre-eclamptic pregnancies. Linear regression analysis showed no correlation between blood pressure or urine protein excretion and ET-1 plasma concentration in non-pre-eclamptic pregnant women. In conclusion, our prospective study indicates that the ET system is, in contrast to most other forms of human hypertension, activated in pre-eclamptic pregnant women.
Endothelin-1 production by a microvascular endothelial cell line treated with Plasmodium falciparum parasitized red blood cells
Authors: BASILICO Nicoletta , SPECIALE Livianna , PARAPINI Silvia , FERRANTE Pasquale , TARAMELLI Donatella
Published: August 2015

In this study, we investigated the production of endothelin 1 (ET-1) by a human microvascular endothelial cell line, HMEC-1, co-cultured with Plasmodium falciparum-parasitized red blood cells (pRBCs). The results indicate that hypoxia increased the basal level of ET-1 production by HMEC-1 cells after 24 or 48h of treatment. However, the co-incubation of HMEC-1 cells with pRBCs, but not with uninfected RBCs, induced a dose-dependent decrease of both constitutive and hypoxia-induced ET-1 production. The inhibition was not due to a decrease in cell viability, as lactate dehydrogenase release remained constant. These results indicate that pRBCs are able to interfere with both the constitutive and stimulated ET-1 release from the microvascular endothelium, thus inducing local modifications of the vascular tone and of the inflammatory response. This could be of relevance in the pathogenesis of the most severe forms of P. falciparum infections, such as cerebral malaria or malaria during pregnancy.
Effects of creatine loading and prolonged creatine supplementation on body composition, fuel selection, sprint and endurance performance in humans
Authors: LOON Luc J.C. van , OOSTERLAAR Audrey M. , HARTGENS Fred , HESSELINK Matthijs K.C. , SNOW Rodney J. , WAGENMAKERS Anton J.M.
Published: August 2015

Most research on creatine has focused on short-term creatine loading and its effect on high-intensity performance capacity. Some studies have investigated the effect of prolonged creatine use during strength training. However, studies on the effects of prolonged creatine supplementation are lacking. In the present study, we have assessed the effects of both creatine loading and prolonged supplementation on muscle creatine content, body composition, muscle and whole-body oxidative capacity, substrate utilization during submaximal exercise, and on repeated supramaximal sprint, as well as endurance-type time-trial performance on a cycle ergometer. Twenty subjects ingested creatine or a placebo during a 5-day loading period (20g·day-1) after which supplementation was continued for up to 6 weeks (2g·day-1). Creatine loading increased muscle free creatine, creatine phosphate (CrP) and total creatine content (P<0.05). The subsequent use of a 2g·day-1 maintenance dose, as suggested by an American College of Sports Medicine Roundtable, resulted in a decline in both the elevated CrP and total creatine content and maintenance of the free creatine concentration. Both short- and long-term creatine supplementation improved performance during repeated supramaximal sprints on a cycle ergometer. However, whole-body and muscle oxidative capacity, substrate utilization and time-trial performance were not affected. The increase in body mass following creatine loading was maintained after 6 weeks of continued supplementation and accounted for by a corresponding increase in fat-free mass. This study provides definite evidence that prolonged creatine supplementation in humans does not increase muscle or whole-body oxidative capacity and, as such, does not influence substrate utilization or performance during endurance cycling exercise. In addition, our findings suggest that prolonged creatine ingestion induces an increase in fat-free mass.