bluuebunny/crossref_metadata_2025 huggingface dataset:
Induction of Heme Oxygenase-1 with Hemoglobin Depresses Vasoreactivity in Rat Aorta
Authors: Gaine Sean P. , Booth Greg , Otterbein Leo , Flavahan Nicholas A. , Choi Augustine M.K. , Wiener Charles M.
Published: April 2003

Septic shock induced by lipopolysaccharide (LPS) produces systemic hypotension and decreased responsiveness to vasoconstrictors. Recently, intravenous injection of hemoglobin (HGB) into rats was found to be protective from a subsequent lethal dose of LPS and was correlated with induction of the enzyme heme oxygenase-1 (HO-1). To determine whether the HGB modulated the vasomotor tone of systemic arteries, we evaluated the effect of in vivo treatment with HGB and LPS on vasoconstrictor responses to phenylephrine (PE) in the isolated rat aorta. Rats (n = 4, for each group) were injected intravenously with rat HGB (200 mg/kg i.v.) or normal saline control (CON) 16 h before sacrifice, and/or LPS (20 mg/kg) or CON 4 h before sacrifice. The descending aorta was dissected into rings and suspended in a modified Krebs solution where vasoconstrictor responses were determined to KCl (60 mM) and PE (10–8 to 10–5 M). LPS, but not HGB, inhibited the vasoconstrictor response to KCl. LPS, HGB, and HGB+LPS inhibited the maximal vasoconstrictor response to PE (PEmax). Induction of HO-1 RNA in the aorta by HGB and by LPS was demonstrated by Northern blot analysis. To determine if induction of HO-1 was related to the effect of LPS or HGB on vascular reactivity, vessels were treated with the HO-1 inhibitor, SnPP9 (30 μM). PEmax in SnPP9+HGB vessels was not different from control, whereas SnPP9+LPS vessels had a marked decrease in PEmax. We conclude that induction of HO-1 does not protect the rat aorta from the vasodepressor effects of LPS in vitro. Our results demonstrate, however, that the induction of HO-1 causes vasodepression, possibly via increased production of carbon monoxide.
Simultaneous in vivo Quantitation of Vascular Endothelial Growth Factor mRNA Splice Variants
Authors: Renner Wilfried , Pilger Ernst
Published: April 2003

Vascular endothelial growth factor (VEGF) is an important regulator of angiogenesis. In vivo expression of four different VEGF isoforms, consisting of 121, 165, 189 or 206 amino acids, has been found in the human organism, with all isoforms arising from a single gene by alternative mRNA splicing. We developed an assay for simultaneous quantitation of VEGF isoform expression using competitive polymerase chain reaction (PCR). RNA was isolated from cells, reverse transcribed to cDNA and coamplified with a synthetical competitor DNA using VEGF specific primers. Amplification products were analyzed electrophoretically and concentration of VEGF transcripts calculated. Concentration of housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH) transcripts was quantitated as above, VEGF gene activity is presented as ratio VEGF mRNA to GAPDH mRNA. Using this assay, we were able to detect and quantitate in vivo expression of VEGF121, VEGF165 and VEGF189 by human peripheral blood mononuclear cells (PBMC). These are the first quantitative data of in vivo VEGF expression by PBMC, suggesting a role for them in the maintenance of the vasculature.
Evidence That an Endothelial Cytosolic Protein Binds to the 3′-Untranslated Region of Endothelial Nitric Oxide Synthase mRNA
Authors: Sánchez de Miguel Lourdes , Alonso Javier , González-Fernández Fernando , de la Osada Jesús , Montón Mercedes , Rodríguez-Feo Juan A. , Guerra José I. , Arriero María M. , Rico Luis , Casado Santos , López-Farré Antonio
Published: April 2003

Changes in the endothelial nitric oxide synthase (eNOS) expression could be involved in the endothelium-dependent vasorelaxing dysfunction associated with cardiovascular diseases. We have recently demonstrated the existence of endothelial cytosolic proteins that bind to the 3′-untranslated region (3′-UTR) of eNOS mRNA and could be involved in eNOS mRNA stabilization. In the present work, we have characterized the cytosolic proteins that bind to 3′-UTR eNOS mRNA. An endothelial cytosolic protein (MW 60-kD) specifically bound to 3′-UTR eNOS mRNA as determined by a cross-linking assay followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The endothelial cytosolic protein recognized a cytidine (C)-rich region within 3′-UTR eNOS mRNA. Furthermore, tumor necrosis factor-α (TNF-α) increased the level of the 60-kD endothelial cytosolic protein. In addition, TNF-α reduced eNOS mRNA levels and this was prevented by coincubation with cycloheximide. Cycloheximide also prevented the binding activity of the endothelial cytosolic protein to 3′-UTR eNOS mRNA. In summary, these data suggest that a 60-kD endothelial cytosolic protein binds to 3′-UTR eNOS mRNA. TNF-α increased the 60-kD protein levels. Cycloheximide prevented the binding activity of the cytosolic protein to 3′-UTR eNOS mRNA related to TNF-α; this effect was associated with greater eNOS mRNA levels. Further specific studies are needed to determine the involvement of this 60-kD endothelial cytosolic protein in the regulation of eNOS mRNA stabilization and in the endothelial dysfunction associated with cardiovascular diseases.
Regulation of Arachidonic Acid Release by Calcium Influx in Human Endothelial Cells
Authors: Millanvoye-Van Brussel Elisabeth , David-Dufilho Monique , Do Pham Thuc , Iouzalen Lahcen , Aude Devynck Marie
Published: April 2003

In response to stimuli, endothelial cells release arachidonic acid, a lipid precursor of various vasoactive substances. We have investigated the relationships between cytosolic Ca2+ movements and arachidonic acid release in human umbilical vein endothelial cells. Histamine, a receptor-dependent agonist, and thapsigargin, a specific inhibitor of sarco-/endoplasmic Ca2+ pumps, time- and dose-dependently increased the release of [1-14C]-arachidonic acid. This release was inhibited by AACOCF3, a selective inhibitor of cytosolic phospholipase A2 (PLA2). In the absence of Ca2+ influx, arachidonic acid release was suppressed in both histamine- and thapsigargin-stimulated cells, despite marked elevations of cytosolic Ca2+ concentration ([Ca2+]i). In the presence of Ca2+ influx, arachidonic acid release was reduced in cells treated with BAPTA, an intracellular Ca2+ buffer, or with SK&F 96365, a receptor-operated Ca2+ channel blocker. Arachidonic acid release was analyzed as a function of the two successive phases of Ca2+ response to stimulation: Ca2+ peak and plateau phase, reflecting Ca2+ mobilization from internal stores and Ca2+ influx, respectively. The amount of arachidonic acid released was directly related to [Ca2+]i values measured at the influx phase with a 80 nM [Ca2+]i threshold, similar to that reported for PLA2 translocation. This suggests that Ca2+ entry from the extracellular space is essential for activating cytosolic PLA2 in human endothelial cells.
MDR1 Gene Expression in Normal and Atherosclerotic Human Arteries1
Authors: Batetta Barbara , Dessì Sandra , Putzolu Marirosa , Sanna Francesca , Spano Ornella , Mulas Maria Franca , Petruzzo Palmina , Cappai Antonello , Brotzu Giovanni
Published: April 2003

Recent studies have shown that a membrane p-glycoprotein, encoded by MDR1 gene, is involved in the transport of free cholesterol from the plasma membrane to endoplasmic reticulum, the site of cholesterol esterification by acyl-CoA:cholesterol acyltransferase (ACAT). Moreover, results deriving from our previous studies have shown that the rate of cell proliferation was positively correlated with cholesteryl ester levels as well as with ACAT and MDR1 gene expression. In this study, lipid content and the expression of the genes involved in cholesterol metabolism such as hydroxy-methylglutaryl coenzyme A reductase (HMGCoA-R), low-density lipoprotein receptor (LDL-R), ACAT and MDR1 have been investigated in control and atherosclerotic arteries. The results have shown that the levels of cholesteryl ester increase with the age of cadaveric donors in arteries prone to atherosclerosis (abdominal aorta, superficial femoral artery) and become predominant in advanced atherosclerotic lesions. The mRNA levels of ACAT and MDR1 showed the same age correlation, reaching the highest values in atherosclerotic specimens. These results suggest that MDR1 may be involved in the accumulation of intracellular cholesterol ester levels found in atherosclerotic lesions. Moreover, the levels of HMGCoA-R, LDL-R and ACAT gene expressions progressively increased with the age of cadaveric donors; conversely, in atherosclerotic specimens, the mRNA levels of HMGCoA-R and LDL-R drastically decreased while ACAT gene expression reached its maximum. These findings suggest a reactivation of normal homeostatic regulation of cholesterol in advanced and complicated lesions.
Expression of Tie1 and Tie2 Proteins during Reendothelialization in Balloon-Injured Rat Carotid Artery
Authors: Fujikawa Koshi , Presman Eleonora , Isner Jeffrey M. , Varticovski Lyuba
Published: April 2003

The novel endothelial cell tyrosine kinase receptors, Tie1 and Tie2, are essential for vascular development and remodeling in the embryo but little is known regarding the regulation of their expression and their role in the maintenance and repair of the adult vascular system. We examined the expression of Tie1 and Tie2 in normal vessels and during reendothelialization following balloon injury of the adult rat carotid artery. Tie proteins were detected in quiescent endothelial cells of the adult rat carotid artery. Tie1 and Tie2 proteins were also detected in human and rat platelets. A weak expression of Tie1 and Tie2 proteins was detected in young endothelial cells which sparsely repopulated the denuded surface by day 14. Protein levels increased in the confluent layer of endothelial cells by day 28. Based on these observations, we tested whether Tie1 and Tie2 mRNA and protein levels are regulated by cell density. Tie1 and Tie2 expression significantly increased with higher density in cultured human endothelial cells, and this upregulation required cell-cell interaction. These data suggest that Tie1 and Tie2 may play a role in the maintenance and repair of the adult vascular system and that the expression of these proteins is regulated by cell density.
Local Adenovirus-Mediated Delivery of Hirudin in a Rabbit Arterial Injury Model
Authors: Bishop Gregory G. , Wiegman Pete , McNamara Coleen , Din Salah , Sanders John , Hesselbacher Sean , Feldman Mike , McPherson John A. , Humphries John E. , Hammarskjold Marie-Louise , Gimple Lawrence W. , Ragosta Michael , Powers Eric R. , Dickek David , Owens Gary K. , Sarembock Ian J.
Published: April 2003

Intravascular delivery of an E1/E3 deleted adenovirus encoding the hirudin protein reduces neointimal formation in the rat arterial injury model. Given the interspecies variability in response to adenoviral vectors, we tested this same construct in the hirudin-sensitive cholesterol-fed rabbit arterial balloon injury model. We hypothesized that local delivery of an E1/E3-deleted adenovirus encoding hirudin (Ad-Hir) in addition to early hirudin infusion would limit neointimal formation compared to early hirudin alone. Methods and Results: Local delivery of Ad-Hir, 2.5 × 1010 PFU/ml, using a double balloon catheter [n = 6 vessels (v)] produced a 79% reduction in vessel wall thrombin activity at 48 h after balloon angioplasty (BA) compared with vehicle (Veh, n = 6v; p = 0.05). In chronic experiments, hypercholesterolemic rabbits underwent femoral BA, and received either early hirudin alone (n = 9v) or early hirudin plus locally delivered Ad-Hir (early hirudin + Ad-Hir; n = 9v), an E1/E3-deleted adenovirus encoding β-galactosidase (early hirudin + AdGal; n = 7v), or Veh (early hirudin + Veh; n = 10v). Early hirudin + Ad-Hir did not limit the arterial response to injury versus the other groups at 4 weeks after BA. Plaque area, cross-sectional luminal area narrowing by plaque, and T cell infiltration were significantly increased in the adenovirus- versus non-adenovirus-treated arteries. Plaque area correlated with T cell density. Conclusion: Following BA in cholesterol-fed rabbits, local transduction with A-Hir produced a marked reduction in vessel wall-associated thrombin activity. However, this strategy increased rather than decreased the arterial response to BA injury. Our results suggest that the lack of therapeutic effect resulted from adenovirus-stimulated plaque formation, possibly resulting from a T cell-mediated inflammatory response.
Kinetics of the Different Steps during Neutrophil Migration through Cultured Endothelial Monolayers Treated with Tumour Necrosis Factor-α
Authors: Luu N. Thin , Rainger G. Ed , Nash Gerard B.
Published: April 2003

To enable a better understanding of the regulation of neutrophil migration, we investigated the kinetics of adhesion and migration over, through and under endothelial monolayers. Neutrophils were perfused over human umbilical vein endothelial cells (HUVEC) which had been treated with tumour necrosis factor-α (TNF; 2–1,000 U/ml) for 4 h. Videomicroscopy showed that transendothelial migration was complete within about 5 min of completion of perfusion of a bolus of neutrophils. Separate populations of adherent cells could then be observed, either rolling, migrating over the surface of the HUVEC or migrating underneath, at different characteristic speeds. Increasing concentration of TNF had little effect on the kinetics of migration, but shifted the balance from rolling adhesion to transendothelial migration. When individual neutrophils were followed from the moment they bound to HUVEC treated with 100 U/ml TNF, we found that ∼40% immobilised essentially immediately on contact, while ∼40% immobilised after rolling for varying periods (average 26 s) and ∼20% rolled continuously. Most of the immobilised cells went on to migrate through the monolayer after spending 20–200 s migrating on top, and took about 60 s to pass through. Overall, the time from first binding to completion of transmigration averaged 152 s (range ∼60–240 s). Interestingly, neutrophils moved relatively slowly on top of the monolayer (about 8 μm/min) but more rapidly underneath (about 16 μm/min). We suggest that the different stages during neutrophil transmigration have characteristic kinetics with separate control mechanisms, which critically influence the efficiency and rate of clearance from the vasculature.
Significance of Nitric Oxide and Peroxynitrite in Permeability Changes of the Retinal Microvascular Endothelial Cell Monolayer Induced by Vascular Endothelial Growth Factor
Authors: Marumo Takeshi , Noll Thomas , Schini-Kerth Valérie B. , Harley Elizabeth A. , Duhault Jacques , Piper Hans M. , Busse Rudi
Published: April 2003

Reactive oxygen species (ROS) play an important role in signaling pathways stimulated by growth factors in vascular cells. We investigated whether vascular endothelial growth factor (VEGF), which is upregulated in diabetic retinopathy and atherosclerosis, is able to enhance production of ROS, and if so, whether ROS modulate endothelial permeability. ROS levels in bovine retinal microvascular endothelial cells (BMEC) were measured by the oxidation of 2′,7′-dichlorodihydrofluorescein (DCHF), and permeability was examined by monitoring the passage of albumin through BMEC monolayers. VEGF stimulated oxidation of DCHF in BMEC, an effect which was inhibited by superoxide dismutase (SOD) and the nitric oxide (NO) synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), but not by D-NAME. Urate, a scavenger of peroxynitrite, attenuated the VEGF-induced oxidation of DCHF. VEGF elicited a significant increase in the macromolecule permeability of BMEC monolayers within 30 min. SOD did not modify the basal or the VEGF-stimulated hyperpermeability, but the combination of SOD and VEGF induced a transient reduction in permeability after 10 min. L-NAME, but not D-NAME, enhanced VEGF-induced hyperpermeability without affecting basal values. Urate did not modify the VEGF-induced changes in permeability. In conclusion, VEGF stimulates oxidation of DCHF, which most likely represents peroxynitrite formation, and induces an increase in permeability of BMEC monolayers. Activation of NO synthase seems to counteract this stimulatory effect of VEGF on endothelial permeability.
Interaction between Wall Shear Stress and Circumferential Strain Affects Endothelial Cell Biochemical Production
Authors: Qiu Yuchen , Tarbell John M.
Published: April 2003

The wall shear stress (WSS) of flowing blood and the circumferential strain (CS) driven by the pressure pulse interact to impose a dynamic force pattern on endothelial cells (ECs) which can be characterized by the temporal phase angle between WSS and CS, a quantity which varies significantly throughout the circulation. To study the interaction of WSS and CS on endothelial production of vasodilators (prostacyclin and nitric oxide) and a vasoconstrictor (endothelin-1), bovine aortic ECs were cultured on the inner surface of compliant tubes and subjected to various flow conditions: steady shear (10 dyn/cm2), oscillatory shear (10 ± 10 dyn/cm2, rigid tube), and oscillatory shear (10 ± 10 dyn/cm2) with CS (8%) either in or out of phase with shear. The 4-hour production rates of vasoactive agents show that steady shear stimulates the highest production of vasodilators whereas oscillatory shear stimulates the highest vasoconstrictor production. The addition of CS in concert with oscillatory shear enhances the production of vasodilators and inhibits the production of vasoconstrictors, and this effect is modulated by the phase angle between WSS and CS. These data suggest that the interactions of WSS and CS are important in vascular regulation and remodeling.
Gender Differences in Cutaneous Laser Doppler Flow Response to Local Direct and Contralateral Cooling
Authors: Cankar Ksenija , Finderle Žare , Štrucl Martin
Published: April 2003

To investigate the role of sympathetic neurovascular reactivity in the gender differences of cutaneous, cold-induced vasomotor response, we compared direct (at the site of cooling) and indirect (at a site remote from the cooling site) response measured by laser Doppler (LD) flowmetry in 12 healthy males and 12 healthy females. The females underwent testing twice, once in the follicular and once in the luteal phase of the menstrual cycle. We measured LD flow before and during local cooling of one hand at 15°C. We found that local cooling evokes a significantly greater decrease in cutaneous LD flow in females than in males in direct as well as in indirect response conditions (p < 0.05). Comparing the response in females in the different phases of menstrual cycle, we obtained a significantly greater direct response to local cooling in the luteal phase than in the follicular phase (p < 0.05). In contrast, there was no menstrual-cycle-dependent difference in the indirect response to cold. The results of our study strongly indicate that sympathetic neural reactivity, as assessed by way of an indirect response to a cold stimulus, significantly contributes to gender differences in the response to local cooling. In contrast, the variation in microvascular responsiveness to cold exposure due to the menstrual cycle is most probably caused by local vascular mechanisms rather than by variation in sympathetic neural reactivity to local cooling.
Low-Dose Cerivastatin Inhibits Spontaneous Atherogenesis in Heterozygous Watanabe Hyper lipidemic Rabbits
Authors: Pauletto Paolo , Puato Massimo , Faggin Elisabetta , Sartore Saverio
Published: April 2003

The aim of this study was to investigate whether cerivastatin (BAYw6228), a new potent 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitor, was able to prevent atherogenesis in heterozygous Watanabe heritable-hyperlipidemic (WHHL) rabbits, a model never tested before using this HMG-CoA reductase inhibitor. The heterozygous WHHL rabbits of our breeding developed mild hypercholesterolemia along with focal atherosclerotic lesions in the thoracic aorta. A 9-week treatment with cerivastatin at doses comparable to those used in humans (50 μg/kg/day) reduced serum total cholesterol levels (from 94.4 ± 10.9 to 43.6 ± 10.5 mg/dl, p < 0.005) and prevented aortic lesion development (intima/media ratio: 0.058 ± 0.032 vs 0.946 ± 0.282 in the placebo group, p < 0.0005). Using a panel of monoclonal antibodies specific to macrophages and able to recognize different smooth muscle cell (SMC) phenotypes, we observed that cerivastatin treatment affected the differentiation properties of SMCs and drastically reduced SMC and macrophage accumulation in the intima of the thoracic aorta. These data show that in the presence of moderate atherosclerotic lesions, such as those of heterozygous WHHL rabbits, low doses of cerivastatin exert an antiatherogenic effect.
Cyclic Nucleotide Hydrolysis in Bovine Aortic Endothelial Cells in Culture: Differential Regulation in Cobblestone and Spindle Phenotypes
Authors: Keravis Thérèse , Komas Narcisse , Lugnier Claire
Published: April 2003

Cyclic nucleotide phosphodiesterases (PDEs) were investigated in cultured bovine aortic endothelial cells having two phenotypes, cobblestone and spindle, representing, respectively, the resting and angiogenic phenotypes in vivo. Spindle cell homogenates displayed higher hydrolytic activities towards cAMP (52%) and cGMP (10-fold). These increases were due to: (1) increased number of spindle PDE isozymes in the cytosolic fraction (for cAMP: PDE1, PDE2, PDE3 and PDE4 compared to PDE2 and PDE4 in cobblestone; for cGMP: PDE2 and PDE5 compared to PDE2 in cobblestone); (2) increased spindle-specific activities of cytosolic and particulate PDE2, cytosolic PDE3 and particulate PDE4. These changes were associated with an increase in spindle transcripts: 7.5 kb PDE3A (6-fold) and 7.0 kb PDE4D (3-fold). Moreover, cAMP hydrolysis in the two phenotypes was differently regulated by 5 μM cGMP: 60% increase in total cAMP-PDE activity in cobblestone homogenate related to PDE2 stimulation; 30% decrease in spindle homogenate related to PDE3 inhibition. This underlines the roles played by PDE2, PDE3 and PDE5 in the cross-talk involving the two cyclic nucleotides. These changes in PDE isozyme expression along with the cross-talk between cAMP and cGMP may well modulate NO production and consequently might participate in angiogenesis, making PDEs potential targets to modulate angiogenesis.
Inhibition of Nitric Oxide Synthesis by Systemic NG-Monomethyl-L-Arginine Administration in Humans: Effects on Interstitial Adenosine, Prostacyclin and Potassium Concentrations in Resting and Contracting Skeletal Muscle
Authors: Frandsen Ulrik , Bangsbo Jens , Langberg Henning , Saltin Bengt , Hellsten Ylva
Published: April 2003

We examined whether the formation or the release of the vasodilators adenosine, prostacyclin (PGI2) and potassium (K+) increase in skeletal muscle interstitium in response to nitric oxide synthase (NOS) inhibition. Five subjects performed one-legged knee extensor exercise at 30 W without (controls) and with prior NG-nitro-L-arginine methyl ester (L-NAME) infusion (4 mg/kg, intravenously). Samples from the interstitial fluid were obtained at rest, during exercise and after exercise with the microdialysis technique. Interstitial adenosine in controls increased (p < 0.05) from 0.11 ± 0.03 μmol/l at rest to 0.48 ± 0.06 μmol/l during exercise. Interstitial adenosine during exercise in L-NAME was similar (p > 0.05) to controls. The 6-keto-prostaglandin F1α concentration in controls was 1.17 ± 0.20 ng/ml at rest and increased (p < 0.05) to 1.97 ± 0.30 ng/ml during exercise and was further elevated (p < 0.05) to 2.76 ± 0.38 ng/ml after exercise and these concentrations were not different (p > 0.05) in L-NAME. The interstitial K+ concentration in controls increased (p < 0.05) from 4.1 ± 0.1 mmol/l at rest to 9.5 ± 0.5 mmol/l during exercise. The interstitial K+ concentration during exercise (6.7 ± 0.4 mmol/l) was lower (p < 0.05) in L-NAME than in controls. The present findings demonstrate that the muscle interstitial concentrations of adenosine, PGI2 and K+ during exercise are not increased with systemic NOS inhibition. Thus, the lack of effect of NOS inhibition on the rate of blood flow to contracting human skeletal muscle does not appear to be due to compensatory formation or release of adenosine, PGI2 and K+ in the muscle interstitium. The present study also supports a role for PGI2 in the regulation of blood flow during exercise.
Characterization of the Secreted Form of Endothelial-Cell-Specific Molecule 1 by Specific Monoclonal Antibodies
Authors: Bechard David , Meignin Véronique , Scherpereel Arnaud , Oudin Severine , Kervoaze Gwenola , Bertheau Philippe , Janin Anne , Tonnel André-Bernard , Lassalle Philippe
Published: April 2003

Endothelial-cell-specific molecule 1 (ESM-1) is a recently identified endothelial cell molecule. As ESM-1 mRNA is preferentially expressed in human lung and kidney tissues, and as ESM-1 mRNA expression is regulated by inflammatory cytokines, ESM-1 is thought to play a role in the vascular contribution to organ-specific inflammation. In order to define its behavior, mouse anti-ESM-1 monoclonal antibodies were developed, and three distinct epitopes were mapped, which allowed development of a specific ELISA assay, immunohistological staining and immunoblot analysis. Here, we demonstrate that ESM-1 is present in cell lysates of human endothelial cells (human umbilical vein endothelial cells) with an apparent molecular weight of 20 kD. In contrast, the secreted form of ESM-1 is shifted to an apparent molecular weight of 50 kD, indicating that the secreted form of ESM-1 is posttranslationally modified. By ELISA, we show that the secretion of ESM-1 is significantly enhanced in the presence of TNFα. In contrast, the spontaneous as well as TNFα-induced secretion of ESM-1 is strongly inhibited by IFNγ. Moreover, ESM-1 was detected in the serum of healthy subjects at an average concentration of 1.08 ng/ml, and we demonstrated that the serum level of ESM-1 is dramatically increased in patients presenting a septic shock. Analysis of ESM-1 expression in normal human tissues by immunohistochemistry showed that ESM-1 is localized in the vascular network, but also in the bronchial and renal epithelia. Our results demonstrate that ESM-1 is mainly expressed in the vascular endothelium both in vitro and in vivo, but also by different epithelia. ESM-1 may represent a new marker of endothelial cell activation, and may have a functional role in endothelium-dependent pathological disorders.
Cytochrome P450 Activity and Endothelial Dysfunction in Insulin Resistance
Authors: Katakam Prasad V.G. , Hoenig Margarethe , Ujhelyi Michael R. , Miller Allison W.
Published: April 2003

Impaired endothelium-dependent relaxation attributable to nitric oxide/prostacyclin-independent factor (endothelium-dependent hyperpolarizing factor; EDHF) has been demonstrated in the small mesenteric arteries of insulin-resistant rats. The purpose of this study was to determine if modulation of the cytochrome P450 enzyme system would restore EDHF-mediated relaxation in insulin-resistant rats. Sprague-Dawley rats were randomized to control (n = 32) or insulin-resistant (n = 32) groups. Each group was further randomized to treatment (n = 48) or placebo (n = 16). Miconazole (3 days) and phenobarbital (3 and 14 days) achieved cytochrome P450 inhibition and induction, respectively. Following drug treatment, mean arterial pressure was measured and vascular function was assessed in small mesenteric arteries in vitro. Specifically, acetylcholine-induced relaxation alone and in the presence of indomethacin plus N-nitro-L-arginine (LNNA) or KCl was determined. Miconazole reduced the maximal relaxation in response to acetylcholine in control rats. Similarly, in the presence of LNNA plus indomethacin, acetylcholine-induced relaxation was impaired in the miconazole-treated control group versus the placebo group, whereas relaxation in the presence of KCl was unchanged. Miconazole did not affect relaxation in insulin-resistant arteries. In contrast, 3- and 14-day treatment with phenobarbital significantly improved acetylcholine-induced relaxation in insulin-resistant arteries. Likewise, acetylcholine-mediated relaxation in the presence of LNNA plus indomethacin was also improved after phenobarbital treatment, while relaxation in the presence of KCl was unchanged. Phenobarbital treatment did not affect the control group. Miconazole treatment increased the mean arterial pressure in control rats, while 14-day phenobarbital treatment normalized the mean arterial pressure in insulin-resistant rats. Cytochrome P450 induction results in the restoration of EDHF-mediated relaxation in small mesenteric arteries and the normalization of mean arterial pressure in insulin-resistant rats. Thus, endothelial dysfunction secondary to insulin resistance can be reversed by the induction of cytochrome P450.
Role of Kinins in the Renoprotective Effect of Angiotensin–Converting Enzyme Inhibitors in Experimental Chronic Renal Failure
Authors: MacLaughlin Myriam , Monserrat Alberto J. , Muller Angélica , Matoso Mirian , Amorena Carlos
Published: April 2003

The aim of this study was to investigate whether the renoprotective effect of angiotensin–converting enzyme inhibitors (ACEIs) following 5/6 renal mass reduction is due in part to the potentiation of kinins. Three groups of rats with 5/6 renal mass reduction were studied during the 14 weeks following surgery. One group received no therapy (control); the second group was treated from the beginning with the ACEI ramipril (1 mg/kg/day) added to the drinking water, and the last group received ramipril plus a β2–bradykinin antagonist, HOE 140 (500 μg/kg/day) via osmotic minipumps. Plasma creatinine did not change in any group during the study. Urinary protein excretion rose in the controls from 9.18±1.6 to 45.0±5.6 mg/24 h at the end of the study. In ramipril group proteinuria was prevented (initial 7.5±1.0 and final 8.6±0.8 mg/24h). The effect of ramipril was abolished by HOE 140 (initial 11.6±2.0 and final 38.9±11 mg/ 24h). The systolic blood pressure of the controls increased from 106±2 to 144±5mmHg at the 14th week. Ramipril abolished the increase in systolic blood pressure. The effect of ramipril was reverted by HOE 140 (initial 108±2 and final 140±9 mmHg). Control rats had more severe histopathologic changes. Those animals receiving ramipril + HOE 140 displayed less severe glomerular changes, while rats treated only with ramipril had mild alterations. Thus the glomerular injury score was 2.11±0.32 for controls, 1.53±0.52 for rats treated with ramipril + HOE 140, and 0.06±0.04 for rats treated only with ramipril. The glomerular area was 20,886±1,410, 19,693±2,200 and 14,352±3,200 μm2, respectively, for the 3 groups. These results suggest that the protective effect of ACEIs in the development of chronic renal failure is partially mediated by kinins.
Superoxide–Mediated Glomerulopathy in the Endotoxin–Treated Pregnant Rat
Authors: Faas M.M. , Schuiling G.A. , Valkhof N. , Baller J.W.F. , Bakker W.W.
Published: April 2003

In the present study the role of superoxide in the glomerular damage in the low–dose endotoxin–infused pregnant rats was investigated. On day 14 of pregnancy, 12 rats were infused for 1 h with 1.0 μg/kg bw endotoxin via a permanent jugular vein cannula. Of these rats, 6 were treated with SOD both prior to endotoxin infusion (7,000 U/kg) and 30 min (7,000 U/kg) and 4 h (14,000 U/kg) after the start of the infusion (SOD rats). The other 6 rats received no SOD treatment (endotoxin rats). Control pregnant rats were infused for 1 h with saline (saline rats; n = 6). Urinary albumin was measured on days 15 and 19 of pregnancy. On day 21, rats were sacrificed and kidney specimens were snap–frozen. Cryostat kidney sections were stained for fibrinogen, ecto–ATP diphosphohydrolase (e–ATPase) activity, polymorphonuclear cells, monocytes and various adhesion molecules on the endothelium and the leukocytes. SOD treatment appeared to significantly prevent the increased urinary albumin excretion and the decrease of glomerular e–ATPase activity which were observed in endotoxin–treated rats. This effect of SOD treatment after endotoxin infusion was associated with a significant inhibition of glomerular monocyte influx and a significant inhibition of adhesion molecule expression (glomerular ICAM–1 and VCAM–1 and leukocyte LFA–1 and VLA–4).The present data suggest that in the endotoxin–infused pregnant rat, production of superoxide in the first few hours after the infusion plays a role in the induction of glomerular damage, leading to albuminuria and diminished e–ATPase expression during the following days.
Urinary Dopamine and Renal Handling of L–DOPA in Fasted Spontaneously Hypertensive Rats
Authors: Dantonello Tobias M. , Küster Eberhard , Mühlbauer Bernd
Published: April 2003

A defective renal dopaminergic system has been suggested to contribute, via impaired sodium excretion, to the pathogenesis of hypertension. Data according renal dopamine (DA) release in hypertension, however, are inconsistent. In the present study, we compared urinary DA excretion (UDAV), plasma free DA (PDA), and renal tissue DA contents (TDA) of young spontaneously hypertensive rats (SHR), Wistar–Kyoto (WKY), and Sprague–Dawley (SD) rats. Since the protein intake dominantly controls UDAV, fasted animals were used to exclude the influence of feeding. Conscious WKY and SHR had a similar UDAV which was lower compared to SD rats. Thiopental anesthesia increased UDAV in SHR and WKY but not in SD rats. TDA was higher in SHR compared to SD and WKY rats. To investigate the tubular capacity to generate DA, the response to L–DOPA infusion was assessed in two doses. 1 nmol/min/100 g body weight L–DOPA increased UDAV approximately 30–fold in all strains but did not affect tubular sodium excretion or renal hemodynamics. In contrast, infusion of 3 μmol/min/100 g body weight L–DOPA increased UDAV by five orders of magnitude and induced natriuresis, diuresis, and tachycardia. These effects were assigned to an increase in PDA and no significant differences were observed among the strains. We conclude that, regarding renal DA, (1) the differences among SHR, WKY, and SD rats rather appear to be strain related than hypertension associated; (2) the renal capacity of DA generation from L–DOPA is not impaired in SHR; (3) tubular DA at physiological concentrations does not alter sodium excretion significantly in normo– or hypertensive rats, and (4) the influence of anesthesia on UDAV should be considered in comparative studies.
Chronic Interstitial Damage in Proteinuria
Authors: Sheerin Neil S. , Sacks Steven H.
Published: April 2003

Tubulointerstitial injury is seen in some patients with glomerular proteinuria and when present is a poor prognostic indicator. However, the mechanism by which proteinuria results in tubular and interstitial damage is unknown. Activation of the complement system has been implicated in many forms of tissue injury, including immune–mediated renal disease. Immunohistochemical studies suggest that complement is deposited on the tubular epithelium in proteinuric states raising the possibility that complement activation may contribute to tubular injury. In this review, we discuss how complement proteins reach the tubular epithelium and why the complement system is activated at this site. We also discuss the effects this may have on tubular cells and how this could result in progressive interstitial disease. The possibility that complement inhibition may reduce progression of tubulointerstitial injury is also considered.
Role of Tubular Cells in Progressive Renal Disease
Authors: van Kooten Cees , Langers Alexandra M.J. , Bruijn Jan A. , Daha Mohamed R.
Published: April 2003

It is generally accepted that the progressive loss of kidney function results from a pathogenic process that is independent of the original etiology, functioning as a final common pathway. Part of this response is characterized by triggering of interstitial infiltration and induction of tubular damage. As a consequence, tubular epithelial cells (TEC) can become activated and begin to express several inflammatory mediators. In the present review, we will summarize the potential role of TEC in progressive renal disease. Much emphasis will be put on studies using in vitro cultured TEC. These studies have provided more insight into the different signals involved in the regulation of the production of inflammatory mediators like complement, cytokines and chemokines, as well as progression factors like growth factors and matrix component by TEC.
Mechanisms of Distal–Nephron Li+ Reabsorption during Dietary K+ Restriction in Rats
Authors: Emamifar Mahmoud , Shalmi Michael , Thomsen Klaus , Christensen Sten
Published: April 2003

The mechanism by which dietary K+ restriction induces distal–nephron Li+ reabsorption was investigated by administration of bendroflumethiazide (BFTZ) or vehicle in conscious Wistar rats. Changes in fractional excretion of Li+ following administration of amiloride (ΔFELi) were used as an index of distal tubular Li+ reabsorption. The results revealed an absence of distal tubular Li+ reabsorption in K+–replete rats (ΔFELi = 3.6±2.4%), in contrast to K+ restriction in which ΔFELi was 24.0±2.7%. The distal tubular Li+ reabsorption in K+–depleted rats was significantly reduced by preadministration of BFTZ (ΔFELi = 9.2±0.9%). The fractions of Li+ and Na+ reabsorbed in the amiloride–sensitive segment were different in K+–replete rats (9±6 vs. 60±6%), but similar in K+–depleted rats (61±5 vs. 73±4%). BFTZ administration to K+–depleted rats resulted in a proportional decrease in these fractions, suggesting competition between Na+ and Li+ for reabsorption in the distal–nephron segment during K+ depletion. These results are compatible with the hypothesis that during K+ depletion the reabsorption of Li+ in the distal–nephron segment is competitively inhibited by Na+.
Effect of Intrarenal Infusion of Angiotensin–(1–7) in the Dog
Authors: Heller J. , Kramer H.J. , Malý J. , Červenka L. , Horáček V.
Published: April 2003

Angiotensin–(1–7), (Ang–(1–7)), a metabolite of Ang II and /or Ang I, was infused into the renal artery (i.r.a) of anesthetized dogs in order to demonstrate its possible direct renal action. The dose administered, 15 Ìg/kg BW/min in isotonic saline (0.072 ml/kg BW/min) throughout the experiment, did not influence the systemic arterial pressure and water and sodium excretion from the contralateral noninfused kidney. Renal blood flow (RBF) was measured by an electromagnetic flowmeter, glomerular filtration rate (GFR) by (exogenous) creatinine clearance. In other groups of animals, either EXP 3174, an AT–1 receptor antagonist alone (30 Ìg/kg BW/ min) or together with Ang–(1–7) (15 Ìg/kg BW/min), were infused. In the last group, the AT–2 receptor antagonist PD 123319, 10 Ìg/kg BW/min, was added to the infusion of Ang–(1–7). A small but significant decrease of RBF from 4.51±0.32 to 3.8±0.29 ml/g BW/min occurred after Ang–(1–7); this decrease was very similar when PD 123319 was added. However, an increase to 4.98±0.34 ml/g BW/min was seen after the addition of EXP 3174 to the i.r.a. infusion of Ang–(1–7); this increase was similar to the increase observed after EXP 3174 alone (5.21±0.33; p<0.02 in both cases). A very small but significant increase in GFR was seen after Ang–(1–7) + EXP 3174 or after the AT–1 blocker alone (0.64±0.049 and 0.62±0.05 vs. 0.6±0.05 ml/g BW/min in the Time Control Group, p<0.01 and 0.05, respectively). Water, sodium and urea excretion rates were increased in all groups infused with Ang–(1–7); after the combination of Ang–(1–7) + EXP 3174, all increases were higher than after every substance alone; however, statistical significance (p<0.05) was reached in sodium excretion values only. Potassium excretion rates were increased just in those groups in which EXP 3174 was present in the infusion fluid. In summary, Ang–(1–7) i.r.a. infusion in the dog is followed by increases in water, sodium and urea (but not potassium) excretion rates, highly probably of tubular origin. This effect is not completely blocked by the AT–1 – and not at all by the AT–2 receptor antagonist – thus indirectly suggesting another receptor could play a role. A small decrease in RBF disappears after EXP 3174, thus indicating an AT–1 receptor action.
Pressor and Renal Effects of Intracerebroventricularly Administered Angiotensins II and III in Rats
Authors: Chen Chuen-Yuan , Huang Wann-Chu
Published: April 2003

Aims: Experiments were performed to assess the effects of intracerebroventricular (ICV) angiotensin (ANG) III on blood pressure and renal function in rats with normal and high sodium intake and to compare these effects with those produced by ICV ANG II. Methods: Male Sprague–Dawley rats on a normal sodium (0.3%) diet and a normal sodium diet plus 1% NaCl as drinking water were administered ANG II and ANG III ICV through a chronically implanted cannula. Blood pressure and renal clearance function responses were measured before and during peptide administrations. The effect of ICV ANG III on the renal efferent nerve activity was also evaluated. Results: ICV injections of ANG II and ANG III at 5 pmol in rats on a normal sodium diet did not significantly alter the blood pressure, but significantly increased renal plasma flow, glomerular filtration rate, urine flow, and absolute and fractional excretions of sodium and potassium. Increased doses of ANG II and III (10, 50 and 100 pmol) significantly increased blood pressure and further enhanced these renal functional indices. Central ANG–III–induced increases in blood pressure and renal functional indices were not significantly different from those produced by ANG II at each corresponding dose. The pressor and renal effects of ANG III were blunted by a specific antagonist, Ile7–ANG III. ICV administration of ANG III decreased the renal efferent nerve activity. In rats with dietary NaCl loading, ICV injections of ANG II and III also significantly enhanced renal function. Conclusions: Centrally administered ANG III is as potent as ANG II in causing pressor and renal effects in rats on normal and high sodium intake. As ANG II, brain ANG III reduced renal efferent nerve activity which may be partly accounted for the augmented renal function.
FcγRIIa Polymorphism in Systemic Lupus erythematosus
Authors: Tan S.Y.
Published: April 2003

FcγRIIs are the most widely distributed of the Fcγ receptor family and play an important role in the clearance of immune complexes. Evidence that the FcγRIIa–R131 allotype is less able to process and clear immune complexes effectively suggests that this may be a disease susceptibility factor for systemic lupus erythematosus (SLE). Data from studies published thus far do not agree on the potential role of FcγRIIa polymorphism in the genetics of SLE. Most studies in fact show no evidence for any correlation between polymorphism of FcγRIIa and risk for SLE. However, it remains to be determined whether FcγRIIa polymorphism may play a critical role in certain groups of patients, especially in those of differing ethnic background. Polymorphism of FcγRIIa may also be important in determining disease phenotype, and identification of this influence may have important implications in patient care and in identifying patients for more aggressive therapy.
Blood Pressure and Indices of Glomerular Filtration Area in Hypertensive and Normotensive Prague Rats
Authors: Hellmann H. , Davis J.M. , Thurau K.
Published: April 2003

The involvement of the kidney in the pathogenesis of hypertension has long been recognised, although the specific renal mechanisms underlying this phenomenon are still unknown. A current hypothesis attributes hypertension to a reduction in glomerular filtration area by glomerular loss. The present study analyses the relationship between glomerular number and volume and conscious systolic blood pressure (SBP) in 4- to 53-week-old hypertensive (PHR) and normotensive (PNR) rats of the Prague strain. Adult PHRs had higher SBP, were larger and had larger kidneys than PNRs, but 20% fewer glomeruli. A significant negative correlation between SBP and glomerular number was found in PHR males, but not in PHR females or PNRs. There was no correlation at all between glomerular volume and SBP and, in young animals, both SBP and glomerular number were higher in PHRs than in PNRs. In addition, in adult PHRs, glomerular volume and SBP were higher in males than in females. In summary, a generally valid, causal relationship linking raised blood pressure to decreased glomerular number or volume could not be demonstrated in the Prague rat model of genetically determined hypertension. The nature of the renal mechanism(s) determining the hypertension in this model remains unknown.
Follow-Up of 122 Symptomatic Patients after CABG: Coronary Arteriographic Definition of Disease Progression and Choice of Therapeutic Options
Authors: Hayat Nasser , Shafie MohamedZaki , Al-Ghoul Salah , Abraham M.Thomas , Endrys Jiri
Published: April 2003

Objective: To examine the graft patency and progression of atherosclerosis 8 ± 5 years after coronary artery bypass graft (CABG) surgery in symptomatic patients. The relationship of risk factors to the progression of the disease and the possible degree of anginal relief to repeated postbypass surgery, angioplasty or intensified medical treatment were reviewed. Methods: A retrospective review of medical files and coronary arteriographic studies of 122 consecutive patients who were catheterized from January 1, 1993 to December 31, 1996. Results: At 8 ± 5 years after CABG, 44.3% of saphenous vein grafts had occluded. For the same period, 89.3% of left internal mammary grafts were patent. Diabetes had a better association with progression of disease in native coronary arteries than grafts. Hypercholesterolemia affected the venous graft more. Hypertension inversely affected graft atherosclerosis and to a lesser extent native artery disease progression. Anginal class improved in 91% of patients having angioplasty. Repeat surgery improved 66% of the patients. Intensified medical intervention helped 50% of the group who were not candidates for other interventions. Conclusion: Symptomatic patients with post-CABG have reasonable prognosis. They should be catheterized early. Based on their coronary anatomy and disease burden in their grafted vessels they could benefit from percutaneous transluminal coronary angioplasty (PTCA), repeat CABG or intensive medical treatment. Amongst the three options, those who could have PTCA had better amelioration of their symptoms.
Role of Fine Needle Aspiration, Intraoperative Imprint Cytology and Frozen Section in the Diagnosis of Breast Lumps and Thyroid Lesions
Authors: Francis Issam M. , Das Dilip K.
Published: April 2003

Background and Objectives: Lesions of the thyroid and breast represent the two commonest sources of frozen section in Kuwait. This study investigates the value of intraoperative cytology (IC), preoperative fine needle aspiration cytology (FNAC) and intraoperative frozen section (FS), in improving the diagnostic accuracy of such lesions. Material: Thirty-one breast masses and 45 thyroid lesions were included. Methods: In each case, diagnosis was established by (1) preoperative FNAC, (2) intraoperative IC and (3) FS. Their accuracy was compared to paraffin section diagnosis. Results: Sensitivity of FNAC, IC and FS for breast malignancy was 82.6, 95.8 and 91.7%, respectively, while for thyroid malignancy sensitivity was 68.4, 85.0 and 65%, respectively. All three had 100% specificity and 0% false-positive rates. A 100% diagnostic accuracy was achieved by combined FNAC and IC in breast, and 93.3% with combined IC and FS in thyroid lesions. Conclusion: Intraoperative IC improves the diagnostic accuracy of FNAC and FS in breast and thyroid lesions.