Vascular endothelium

Progressive tumor growth depends on angiogenesis to sustain metabolic needs of tumor cells, thus providing a potential target for cancer therapy. Malignant gliomas have retained their dismal prognosis despite aggressive multimodal conventional therapeutic approaches, illustrating the need for novel therapeutic strategies. Gliomas are a suitable tumor type for probing angiogenesis inhibition as their proliferation is characterized by a prominent proliferative vascular component. In the present review, we discuss the current status and future directions of angiogenesis inhibition in gliomas. We focus on recently developed approaches inducing an antiangiogenic response such as targeted gene delivery, protein tyrosine kinase inhibitors and encapsulated producer cells. Although several of these modalities have shown promising results on their own, the true potential of these novel approaches lies in their combined use with radiotherapy or 'metronomically scheduled' chemotherapy. A combined approach potentially counteracts the selective pressure on hypoxia-resistant malignant tumor cells, circumvents endothelial resistance induced by local cytoprotective responses and enhances the delivery of cytotoxic agents by normalizing vascular physiology. Surrogate markers of angiogenesis currently under study may provide accurate assessment of response in individual patients. Future research on endothelial markers expressed on tumor-associated vasculature as well as endothelial responses to cytotoxic treatment will provide new avenues for molecularly targeted therapy in malignant gliomas. D

1 1 De De ept p of Ca Card r rdio io iolo lo logy gy y a a and nd nd A A Ang ng ngio io iolo lo logy gy gy I I I, He He Hear ar art t t Ce Cen n nte e er, Un Un Univ iv iver er ersi sity ty ty o of f f Fr Fr Frei ei eibu bu b rg g g, , , Ge Ge Germ rm rman an ny; y; y; 2 2 De De Dept pt pt of Bi Bio ol o ogy, Alb lbert t t-L L Lud dw wi i igs--Un Un Uni iver e si sity ty, F F Freib bu bur rg, Ge Ge Germ man an any; y; y; 3 D D Dep p pt o of H He em ma mat t tol lo logy g a a an nd d O O On n ncol log og gy, Un Un Univ iv iver er ersi si sity ty H H Hos ospi pi p ta ta tal l Fr Fr Frei e bu bu burg rg rg, , , Ge G Germ rm man any; y; y; 4 Ex Ex Expe pe peri ri ime me ment nt ntal al al C C Car ar ardi di iol ol olog o ogy y y La La abo bora ra rato to tory ry ry, Un Un Univ iver er ersi si sity ty y Me Medi dica cal l e Ce Cent nter er U Utr trec echt ht, , , Th The e e Ne Neth ther erla la d nd nds s

Aim To study the expression of monocyte chemotactic protein-3 (MCP-3, also known as chemokine CCL-7) in tissue from apical lesions (AL) and to associate MCP-3 expression with symptomatic or asymptomatic apical periodontitis. Methodology To determine the expression of MCP-3 in AL, biopsies obtained during tooth extraction procedures were fixed, subjected to routine processing and diagnosed as apical granuloma (AG) (n = 7) or radicular cyst (RC) (n = 5). As controls, apical periodontal ligament (PDL) specimens from healthy premolars extracted for orthodontics reasons were included (n = 7). All specimens were immunostained for MCP-3 and examined under a light microscope. In addition, homogenates from AL (n = 14) and healthy PDL samples (n = 7) were studied through immunowestern blot. Finally, periapical exudates samples were collected from root canals of teeth having diagnosis of symptomatic (n = 14) and asymptomatic apical periodontitis (n = 14) during routine endodontic treatments and analysed by immunowestern blot and densitometry. Results MCP-3 was detected in AG and RC and localized mainly to inflammatory leucocytes, whereas no expression was observed in healthy PDLs. MCP-3 was also detected in periapical exudate, and its levels were significantly higher in symptomatic than in asymptomatic apical periodontitis. Conclusions MCP-3 was expressed in AL and its levels associated with clinical symptoms. MCP-3 might play a role in disease pathogenesis, possibly by stimulating mononuclear chemotaxis.

A large proportion of the beneficial effects that oestrogens demonstrate on the vasculature are believed to be mediated via direct effects on the vascular wall. In this study we compared a number of oestrogenic compounds isolated from pregnant mare's urine including 17b-oestradiol and oestrone, in terms of their abilities to inhibit stimulated endothelin-1 release from normal human coronary artery endothelial cells (CAEC). We also examined their ability to stimulate expression of constitutive endothelial nitric oxide synthase (eNOS) and explored their effects on cellular angiotensin converting enzyme (ACE). All the oestrogens tested were able to inhibit serum-stimulated ET-1 release. Oestrone and 17a-dihydroequilenin failed to significantly affect cellular eNOS levels. 17b-oestradiol and oestrone significantly increased cellular ACE levels while 17b,D 8,9-dehydroestradiol decreased cellular ACE. We discuss these observations in terms of their potential clinical relevance and use as a means of screening novel oestrogen-like compounds.

Endothelial-derived microparticles (EMPs) are a novel biological marker of endothelium injury and vasomotion disorders that are involved in pathogenesis of cardiovascular, metabolic, and inflammatory diseases. Circulating levels of EMPs are thought to reflect a balance between cell stimulation, proliferation, apoptosis, and cell death. Increased EMPs may be defined in several cardiovascular diseases, such as stable and unstable coronary artery disease, acute and chronic heart failure, hypertension, arrhythmias, thromboembolism, asymptomatic atherosclerosis as well as renal failure, metabolic disorders (including type two diabetes mellitus, abdominal obesity, metabolic syndrome, insulin resistance) and dyslipidemia. This review highlights the controversial opinions regarding impact of circulating EMPs in major cardiovascular and metabolic diseases and summarizes the perspective implementation of the EMPs in risk stratification models.

Endothelin (ET) 1 is a potent vasoconstrictor peptide produced by vascular endothelial cells and implicated in various pathophysiologic states involving abnormal vascular tone. Homozygous ET-1 null mice have craniofacial and cardiac malformations that lead to neonatal death. To study the role of ET-1 in adult vascular physiology, we generated a mouse strain (ET-1 flox/flox ;Tie2-Cre mice) in which ET-1 is disrupted specifically in endothelial cells. ET-1 peptide levels in plasma, heart, lung, kidney, and brain homogenates were reduced by 65% to 80% in these mice. mRNA levels for ET receptors were unaltered except that the ET A receptor mRNA was upregulated in the heart. ET-1 flox/flox ;Tie2-Cre mice had mean blood pressures 10 to 12 mm Hg lower than genetic controls. In contrast, the blood pressure of mice systemically heterozygous for the ET-1 null allele (ET-1 dlox/ϩ mice) was unchanged compared with wild-type littermates. Despite the lower basal blood pressure, acute pharmacological responses to angiotensin II, captopril, phenylephrine, bradykinin, N G -nitro-L-arginine methyl ester, and exogenous ET-1 were normal in ET-1 flox/flox ;Tie2-Cre mice. These results support an essential role of endothelial-derived ET-1 in the maintenance of basal vascular tone and blood pressure. Normal pharmacological responses of ET-1 flox/flox ;Tie2-Cre mice suggest that the renin-angiotensin system, the adrenergic system, and NO are not significantly altered by endothelial ET-1. Taken in conjunction with other lines of genetically altered mice, our results provide evidence for a paracrine vasoregulatory pathway mediated by endothelial cell-derived ET-1 acting on the vascular smooth muscle ET A receptor. (Hypertension. 2010;56:121-128.) Key Words: hypertension Ⅲ endothelium Ⅲ ET A Ⅲ ET B Ⅲ cre/loxP Ⅲ blood pressure Ⅲ gene knockout E ndothelin (ET) 1, originally identified as a potent vaso-

Arginase 2 (Arg2) is a critical target in atherosclerosis because it controls endothelial nitric oxide, proliferation, fibrosis, and inflammation. Regulators of Arg2 transcription in the endothelium have not been characterized. The goal of the current study is to determine the role of specific histone deacetylases (HDACs) in the regulation of endothelial Arg2 transcription and endothelial function. The HDAC inhibitor trichostatin A increased levels of Arg2 mRNA, protein, and activity in both human aortic endothelial cells and mouse aortic rings. These changes occurred in both time- and dose-dependent patterns and resulted in Arg2-dependent endothelial dysfunction. Trichostatin A and the atherogenic stimulus oxidized low-density lipoprotein enhanced the activity of common promoter regions of Arg2. HDAC inhibition with trichostatin A also decreased endothelial nitric oxide, and these effects were blunted by arginase inhibition. Nonselective class I HDAC inhibitors enhanced Arg2 expres...

The chronic inflammation of arterial walls is associated with the development of atherosclerosis. Earlier we reported that avenanthramide (Avn) s-enriched extract of oats (AvnsO) significantly suppressed interleukin (IL)-1β-stimulated secretion of proinflammatory cytokines, such as IL-6, IL-8, and MCP-1, by human aortic endothelial cells (HAEC). The main objective of the current study was to determine if the mechanism of inhibitory effect of these polyphenols from oats on the expression of proinflammatory cytokines is mediated through modulation of nuclear factor κB (NF-κB)-dependent transcription. Confluent HAEC monolayers were treated for 24 h with AvnsO, and synthetically prepared Avn-c suppressed IL-β-stimulated activation of NF-κB in a concentration-dependent manner. CH3-Avn-c, a synthetically prepared methyl ester derivative of Avn-c with a high biological potency, significantly and dose dependently decreased mRNA expression and secretion of IL-6, IL-8, and MCP-1 by HAEC as determined by real-time RT-PCR and ELISA, and it inhibited IL-1β-and TNFα-stimulated NF-κB activation as determined by a NF-κB DNA binding assay and a NF-κB luciferase reporter assay. AvnsO and Avn-c as well as CH3-Avn-c also inhibited the NF-κB-dependent reporter gene expression activated by TNFR-associated factor 2 and 6 (TRAF2, TRAF6) and NFκB-inducing kinase (NIK). CH3-Avn-c also significantly and dose dependently decreased the phosphorylation level of IκB kinase (IKK) and IκB, and prevented IκB degradation as measured by Western blotting. In addition, CH3-Avn-c markedly increased the overall levels of high mass ubiquitin-conjugated protein levels while it mildly inhibited proteasome activity. These observations suggest that Avns, unique polyphenols from oats, decrease the expression of endothelial proinflammatory cytokines at least in part through inhibition of NF-κB activation by inhibiting the phosphorylation of IKK and IκB, and by suppressing proteasome activity.

Vascular responses to hypoxia are heterogeneous and involve the release of vasodilators substances such as nitric oxide (NO) and prostacyclin (PGI 2). In vitro studies have shown that Vitamin K 1 modulates the release of arachidonic acid (AA) in vascular cells, and thus inhibits the capacity of blood vessels to synthesise vasodilator AA metabolites. The aim of our work was to investigate the effects of Vitamin K 1 on the hypoxia-induced vasorelaxation. Hypoxia was induced by changing the gas from 95% O 2 /5% CO 2 to a mixture containing 95% N 2 /5% CO 2. Rat carotid arteries were pre-contracted with phenylephrine (Phe, 10 −8 mol/l) and when the contraction reached a plateau, the bath was bubbled with 95% N 2 /5% CO 2 for 15 min. In intact rings, there was a total relaxation after 15 min of exposure to hypoxia. Removal of the endothelium strongly reduced hypoxia-induced relaxation. In intact rings, indomethacin and l-NAME reduced the hypoxic relaxation after 5 min of exposure but not after 10 or 15 min. Exposure of endothelium-intact rings to Vitamin K 1 (5×10 −6 and 5×10 −5 mol/l), l-NAME +indomethacin as well as the combination of l-NAME +indomethacin + Vitamin K 1 reduced the hypoxic relaxation after 5 and 10 min of exposure but not after 15 min. At 5 × 10 −7 mol/l Vitamin K 1 did not attenuate hypoxia-induced relaxation. It was also found that Vitamin K 1 (5×10 −6 and 5×10 −5 mol/l) inhibited ACh-induced relaxation in normoxic conditions. These results show that the effect of Vitamin K 1 on attenuating hypoxia-induced vasorelaxation is concentration-dependent and probably related to its action on endothelial cells.

Heparin-like polysaccharides possess the capacity to inhibit cancer cell proliferation, angiogenesis, heparanase-mediated cancer cell invasion, and cancer cell adhesion to vascular endothelia via adhesion receptors, such as selectins. The clinical applicability of the antitumor effect of such polysaccharides, however, is compromised by their anticoagulant activity. We have compared the potential of chemically O-sulfated and N,O-sulfated bacterial polysaccharide (capsular polysaccharide from E. coli K5 [K5PS]) species to inhibit metastasis of mouse B16-BL6 melanoma cells and human MDA-MB-231 breast cancer cells in two in vivo models. We demonstrate that in both settings, O-sulfated K5PS was a potent inhibitor of metastasis. Reducing the molecular weight of the polysaccharide, however, resulted in lower antimetastatic capacity. Furthermore, we show that O-sulfated K5PS efficiently inhibited the invasion of B16-BL6 cells through Matrigel and also inhibited the in vitro activity of heparanase. Moreover, treatment with O-sulfated K5PS lowered the ability of B16-BL6 cells to adhere to endothelial cells, intercellular adhesion molecule-1, and P-selectin, but not to E-selectin. Importantly, O-sulfated K5PSs were largely devoid of anticoagulant activity. These findings indicate that O-sulfated K5PS polysaccharide should be considered as a potential antimetastatic agent.

Disabled-2 (DAB2) is an adaptor protein implicated in signal transduction pathways and in protein traffic regulation. Here, we show that DAB2 is highly expressed in human endothelial cells. DAB2 silencing in endothelial cells by lentiviral-mediated small hairpin RNA expression affects cell migration and differentiation into capillary-like structures while increasing cell proliferation and viability. DAB2 knockdown causes activation of the Src-FAK signal pathway, extracellular-signal regulated kinase and c-Jun NH 2 -terminal kinase activation, and inhibition of p38 phosphorylation. In DAB2 silenced endothelial cells, pharmacological inhibition of Src with its specific inhibitor PP2 abolishes focal adhesion kinase activation and restores differentiation of endothelial cells. These results suggest that DAB2, via Src and focal adhesion signaling, plays a role in human endothelial cell function.

Background: Notch signaling pathway controls key functions in vascular and endothelial cells (ECs) where Notch4 plays a major role. However, little is known about the contribution of other Notch receptors. This study investigated regulation of Notch2 and further examined its implication in EC dysfunction.

Background. Cell implantation into ischemic regions has recently been introduced as a novel strategy for therapeutic angiogenesis. Little is known, however, about the process of blood vessel regeneration, particularly that of the inferior vena cava (IVC). The indicators of normal angiogenesis are also unestablished.

Pseudomonas aeruginosa, a common agent of septicemia, enters into human endothelial cellsin vitro but the effects of bacterial infection have not been addressed properly. In this study, human umbilical vein endothelial cells (HUVEC) were infected by the noninvasive PA103 and ...

The prodromal stage of atherosclerotic lesions is already formed during human fetal development. The presence of infections during childhood may increase synergistically the progression of atherogenesis. After delivery, especially those children exposed to severe maternal hypercholesterolemia should be followed up for the onset and development of acute and chronic infections and be included in clinical and noninvasive examinations of vascular function.

Genetic studies have recently revealed a role for transforming growth factor-beta-I (TGF-~I) and its receptors (TGF-~Rs I and II as well as endoglin) in embryonic vascular assembly and in the establishment and maintenance of vessel wall integrity. The purpose of this review is threefold: first, to reassess previous studies on TGF-/~ and endothelium in the light of these recent findings; second, to describe some of the well-established as well as controversial issues concerning TGF-/~ and its regulatory role in angiogenesis; and third, to explore the notion of 'context' with respect to TGF-/~ and endothelial cell function. Although the focus of this review will be on the endothelium, other vascular wall cells are also likely to be important in the pathogenesis of the vascular lesions revealed by genetic studies. ~

To study facial flush after systemic administration of human corticotropin-releasing hormone (hCRH) we injected 100 lag hCRH intravenously to ten healthy young men. The increase in facial temperature was measured by infrared camera. A significant increase in facial temperature of 1.39°C __+ 0.3 was found within 7 min in all patients, which lasted up to 60 min, although facial flushing was visible in only 50% (5/10) of the probands. In a second experiment 100 tag hCRH was then administered to seven other healthy young men. Intra-and extracerebral blood flow velocity changes in the medial cerebral artery (MCA) and external carotid artery (ECA) were measured after hCRH administration by use of Doppler sonography. We found a decrease of intracerebral blood flow which was caused by hyperventilation and was reversible following 6% CO2 hyperventilation during a second injection of 100 gg hCRH. Blood flow velocity in the ECA increased by 111.5 __ 32.9% (compared to baseline level), lasted up to 60 min after hCRH injection, and was not reversible by 6% end-tidal CO2 ventilation. We thus demonstrated that the direct vasodilatory effect of hCRH involves the ECA-supplied vascular territory only. The intracerebral vasoconstrictory effect represents the result of hyperventilation following hCRH injection. The data thus clearly suggest an interaction of hCRH and the vascular endothelium of the ECA, causing a marked blood flow velocity increase and facial flushing.

Tubulointerstitial nephritis (TIN) antigen has been recently identified as a novel basement membrane macromolecule. It consists of a single chain of 58 kDa and exhibits a restricted distribution. The interaction between TIN antigen and laminin or type IV collagen has been studied using solid-phase binding assays and found to be for both macromolecules specific, saturable, and with an affinity in the low micromolar range. In similar assays, TIN antigen did not interact with heparin. In turbidimetry assays, it was found that the presence of TIN antigen did not affect the polymerization of type IV collagen but had a concentration-dependent inhibitory effect on laminin polymerization and on preformed laminin polymers. TIN antigen was able to promote adhesion of epithelial cells derived from kidney tubules and of endothelial cells derived from aorta. The data suggest that TIN antigen may be a macromolecule of importance both for basement membrane ultrastructure and cellular adhesion.

Background-Pulmonary endothelium has metabolic functions including the conversion of angiotensin I to angiotensin II by angiotensin-converting ectoenzyme (ACE). In this study, we have validated an indicator-dilution technique that provides estimations of dynamically perfused capillary surface area (DPCSA) in humans, and we have characterized pulmonary endothelial ACE in vivo. Methods and Results-In 12 adults, single-pass transpulmonary (one or both lungs) hydrolysis of the specific ACE substrate 3 H-benzoyl-Phe-Ala-Pro ( 3 H-BPAP) was measured and expressed as % metabolism (%M) and vϭϪln(1ϪM). We also calculated A max /K m , an index of DPCSA. %M (70.1Ϯ3.2 vs 67.9Ϯ3.1) and v (1.29Ϯ0.14 vs 1.20Ϯ0.12) were similar in both lungs and the right lung, respectively, whereas A max /K m/ /body surface area decreased from 2460Ϯ193 to 1318Ϯ115 mL/min per square meter. Conclusions-Pulmonary endothelial ACE activity can be assessed in humans at the bedside by means of indicatordilution techniques. Our data suggest homogeneous pulmonary capillary ACE concentrations and capillary transit times (t c ) in both human lungs, and similar t c within the normal range of cardiac index. A max /K m in the right lung is 54% of total A max /K m in both lungs, suggesting that A max /K m is a reliable and quantifiable index of DPCSA in humans. (Circulation. 1999;99:1593-1599.)

5-Hydroxy-2-(2,6-diisopropylphenyl)-1H-isoindole-1,3-dione (5HPP-33: 10), which was obtained during our previous structural development studies on thalidomide, was revealed to possess potent anti-angiogenic activity in a human umbilical vein endothelial cell (HUVEC) assay. Thalidomide (1) and its metabolite, 5-hydroxythalidomide (5-HT: 2), which possesses a hydroxyl group at the position corresponding to that of 5HPP-33, as well as IMiDs (immunomodulatory derivatives of thalidomide: 3 and 5), also showed weak or moderate activity in the same assay.

Salmosin is a snake venom-derived novel disintegrin that antagonizes platelet aggregation. In this study, we investigated its functional specificity in tumor angiogenesis. Salmosin significantly inhibited bovine capillary endothelial cell proliferation induced by basic fibroblast growth factor but had no effect on normal growth of the cell. The basic fibroblast growth factor-induced in vivo angiogenesis in the chorioallantoic membrane was disrupted by salmosin treatment without affecting normal embryonic angiogenesis. Adhesion of the bovine capillary endothelial cells to vitronectin was also inhibited by the binding of salmosin to the alpha(v)beta3 integrin. Both the metastatic-tumor growth and the solid-tumor growth that developed in mice were effectively suppressed by salmosin treatment. Several lines of experimental evidence strongly suggest that the tumor-specific antiangiogenic activity of salmosin disrupts tumor growth by blocking the alpha(v)beta3 integrin that is expressed o...

It has been suggested that transforming growth factor-beta1 (TGF-beta1) plays an important role in the pathogenesis of diabetes-induced erectile dysfunction. To investigate the expression and activity of Smad transcriptional factors, the key molecules for the initiation of TGF-beta-mediated fibrosis, in the penis of streptozotocin (STZ)-induced diabetic rats. Fifty-two 8-week-old Sprague-Dawley rats were used and divided into control and diabetic groups. Diabetes was induced by an intravenous injection of STZ. Eight weeks later, erectile function was measured by electrical stimulation of the cavernous nerve (N = 12 per group). The penis was harvested and stained with Masson trichrome or antibody to TGF-beta1, phospho-Smad2 (P-Smad2), smooth muscle alpha-actin, and factor VIII (N = 12 per group). Penis specimens from a separate group of animals were used for TGF-beta1 enzyme-linked immunosorbent assay (ELISA), P-Smad2/Smad2, phospho-Smad3 (P-Smad3)/Smad3, fibronectin, collagen I, and collagen IV western blot, or hydroxyproline determination. Erectile function was significantly reduced in diabetic rats compared with that in controls. The expression of TGF-beta1, P-Smad2, and P-Smad3 protein evaluated by ELISA or western blot was higher in diabetic rats than in controls. Compared with that in control rats, P-Smad2 expression was higher mainly in smooth muscle cells and fibroblasts of diabetic rats, whereas no significant differences were noted in endothelial cells or in the dorsal nerve bundle. Cavernous smooth muscle and endothelial cell contents were lower in diabetic rats than in controls. Cavernous fibronectin, collagen IV, and hydroxyproline content was significantly higher in diabetic rats than in controls. Upregulation of TGF-beta1 and activation of the Smad signaling pathway in the penis of diabetic rats might play important roles in diabetes-induced structural changes and deterioration of erectile function.

This study evaluates the impact of obesity on coronary endothelial function in patients with normal or mild coronary artery disease. BACKGROUND The American Heart Association (AHA) has recently classified obesity as a modifiable risk factor for coronary heart disease.

A reduced nitric oxide availability is a hallmark of endothelial dysfunction occurring early in atherosclerosis. Recently, we have shown that plasma nitrite mirrors acute changes in endothelial nitric oxide synthase activity in various mammals, including humans. Here, we examined the hypothesis that plasma nitrite levels are reduced in humans with endothelial dysfunction and the decrease is correlated with increasing numbers of cardiovascular risk factors (RF). Plasma nitrite concentrations were quantified by flow-injection analysis. The coefficient of variation for repeated measurements of plasma nitrite was <8%, and heart rate and blood pressure at the time of blood sampling had no significant effect on nitrite values measured (n = 10). Baseline levels of plasma nitrite followed a normal distribution in each group studied and decreased progressively with increasing numbers of cardiovascular risk factors (n = 351, p < 0.001): 351 T 13 (0 RF), 261 T 10 (1 RF), 253 T 11 (2 RF), 222 T 18 (3 RF), and 171 T 29 nmol/L (4 RF). Intima media thickness (IMT) and flow-mediated dilation (FMD) were determined via ultrasound. Plasma nitrite and FMD levels were lower, whereas IMT was greater in individuals with endothelial dysfunction (n = 12) compared to healthy volunteers (n = 12). Nitrite correlated significantly with FMD (r = 0.56, p < 0.001) and inversely with IMT (r = À0.49, p < 0.01). Plasma nitrite levels are reliably measurable in humans, indicate endothelial dysfunction, and correlate with cardiovascular risk factors. Future studies are necessary to identify the prognostic relevance of plasma nitrite determination in patients suffering from cardiovascular disease. D 2005 Elsevier Inc. All rights reserved.

The objective is to determine cardiovascular and insulin release effects under metoclopramide (MTC) and dopamine (DA) infusion by using an acute comparative design with the intravenous infusion of both drugs. We evaluated 15 normal (normotensive and normoglycemic) subjects, 13 hypertensive, and 15 type 2 diabetic subjects. Subjects were submitted to an experimental design in which we first gave them a 0.9% saline solution for 30 minutes, and then administered MTC at 7.5 mg kg 21 min 21 through an intravenous infusion during a period of 30 minutes. Although subjects were receiving MTC, we added an intravenous infusion of DA at 1-3 mg kg 21 min 21 during 30 minutes. Blood pressure, heart rate, serum lipid profile, and insulin levels were measured. Sympathetic reactivity by the cold pressor test was also measured. In normotensive subjects, there was a systolic blood pressure and heart rate increase during MTC plus DA infusion. In subjects with diabetes mellitus there was a heart rate increase without changes in blood pressure during the MTC plus DA infusion period. In hypertensive subjects, MTC induced a significant decrease of systolic and diastolic blood pressure. During MTC plus DA period there was an increase of heart rate but no significant changes in blood pressure. During cold pressor test in both diabetic and hypertensive subjects, there were significant increases of both blood pressure and heart rate. Insulin serum levels increased in normotensive and hypertensive subjects but were attenuated in subjects with diabetes mellitus. We conclude that there is a pharmacologic interaction between MTC and DA, that the pressor effects of DA are due to activation to beta and alpha adrenergic receptors, and that the cardiovascular effects of DA in type 2 diabetic subjects are attenuated by a probable defect in sympathetic system and to endothelial dysfunction.

Idazoxan is an a 2 adrenoceptor antagonist and a 1 /a 2 partial agonist that also blocks imidazoline receptors, with an evident preference for the I 2 type. Idazoxan was introduced in 1981 as a specific a 2 antagonist [1], but is also a partial agonist for a 2 [2] and a 1 [3-5] adrenoceptors. It has been widely used as an a 2 antagonist, including many vascular reactivity studies, where it helped the a 2 /a 1 distinction in terms of: pharmacology , muscle and endothelium distribution , electrophysiology [7], functional relevance/interference , including a 1 states and subtypes . However in some vessels, such as rat aorta, the presence and importance of a 2 are negligible . Moreover, idazoxan is a well-established antagonist of imidazoline receptors, for which various implications are discussed . Imidazoline receptors are present in the vascular wall pre-and postsynaptically, in both smooth muscle and endothelial cells, so far involved in proliferation control , without an accepted role in the modulation of vascular contractile activity. However, agmatineinduced relaxation in rat aorta appears to be mediated by I 1 imidazoline receptors .

Regulatory T cells (T regs ) are found at sites of chronic inflammation where they mediate bystander and Ag-specific suppression of local immune responses. However, little is known about the molecular control of T reg recruitment into inflamed human tissues. We report that up to 18% of T cells in areas of inflammation in human liver disease are forkhead family transcriptional regulator box P3 (FoxP3) + T regs . We isolated CD4 + CD25 + CD127 low FoxP3 + T regs from chronically inflamed human liver removed at transplantation; compared with blood-derived T regs , liver-derived T regs express high levels of the chemokine receptors CXCR3 and CCR4. In flow-based adhesion assays using human hepatic sinusoidal endothelium, T regs used CXCR3 and a4b1 to bind and transmigrate, whereas CCR4 played no role. The CCR4 ligands CCL17 and CCL22 were absent from healthy liver, but they were detected in chronically inflamed liver where their expression was restricted to dendritic cells (DCs) within inflammatory infiltrates. These DCs were closely associated with CD8 T cells and CCR4 + T regs in the parenchyma and septal areas. Ex vivo, liverderived T regs migrated to CCR4 ligands secreted by intrahepatic DCs. We propose that CXCR3 mediates the recruitment of T regs via hepatic sinusoidal endothelium and that CCR4 ligands secreted by DCs recruit T regs to sites of inflammation in patients with chronic hepatitis. Thus, different chemokine receptors play distinct roles in the recruitment and positioning of T regs at sites of hepatitis in chronic liver disease.

Hyperhomocysteinemia is an independent risk factor for ischemic cardiovascular diseases, but its causal role in atherothrombosis remains controversial. Proatherogenic and/or prothrombotic effects may underlie the potential causal relation between hyperhomocysteinemia and cardiovascular events. Here, the effects of selective lowering of plasma homocysteine, plasma cholesterol, or both on endothelial function and on atherogenesis in male hyperlipidemic and hyperhomocysteinemic C57BL/6 lowdensity lipoprotein receptor (LDLr) −/− /cystathionine-β-synthase (CBS) +/− -deficient mice were investigated. Second, we evaluated whether selective homocysteine lowering has anti-thrombotic effects in a model of arterial thrombosis. A hyperhomocysteinemic and atherogenic diet was started at the age of 12 weeks. Three weeks later, gene transfer was performed with E1E3E4-deleted adenoviral vectors for hepatocyte-restricted overexpression of CBS (AdCBS) or of the LDLr (AdLDLr), or with the control vector Adnull. In a fourth group, AdCBS and AdLDLr were coadministered. Selective homocysteine lowering but not selective cholesterol lowering restored endothelial function at 6 weeks after gene transfer. Intimal area in the aortic root and in the brachiocephalic artery at 13 weeks was more than 100-fold (p<0.001) smaller in AdLDLr and AdCBS/ AdLDLr mice than in control mice and AdCBS mice. No differences in intimal area were observed between control mice and AdCBS mice. In a model of carotid artery thrombosis, the average time to first occlusion and to stable occlusion were 1.9-fold (p <0.01) and 2.1-fold longer (p<0.01), respectively, in AdCBS-treated mice than in control mice. Taken together, these data show that correction of endothelial dysfunction following selective homocysteine lowering has anti-thrombotic but no antiatherogenic effects.

Activation of the complement system contributes significantly to the pathogenesis of numerous acute and chronic diseases. Recently, a monoclonal antibody (5Gl. 1) that recognizes the human complement protein C5, has been shown to effectively block C5 cleavage, thereby preventing the generation of the pro-inflammatory complement components C5a and C5b-9. Humanized 5Gl. 1 antibody, Fab and scFv molecules have been produced by grafting the complementarity determining regions of 5Gl. 1 on to human framework regions. Competitive ELISA analysis indicated that no framework changes were required in the humanized variable regions for retention of high affinity binding to C5, even at framework positions predicted by computer modeling to influence CDR canonical structure. The humanized Fab and scFv molecules blocked complement-mediated lysis of chicken erythrocytes and porcine aortic endothelial cells in a dose-dependent fashion, with complete complement inhibition occurring at a three-fold molar excess, relative to the human C5 concentration. In contrast to a previously characterized anti-C5 scFv molecule, the humanized h5Gl. 1 scFv also effectively blocked C5a generation. Finally. an intact humanized h5Gl.l antibody blocked human complement lytic activity at concentrations identical to the original murine monoclonal antibody. These results demonstrate that humanized h5Gl. 1 and its recombinant derivatives retain both the affinity and blocking functions of the murine 5G 1.1 antibody, and suggest that these molecules may serve as potent inhibitors of complement-mediated pathology in human inflammatory diseases. (0 1997 Elsevier Science Ltd. All rights reserved.

The reversibility of pulmonary arterial hypertension (PAH) in children with congenital heart disease (CHD) is strongly associated with the degree of intimal proliferation, vessel narrowing, and number of circulating endothelial cells (CECs). Circulating endothelial cells may arise from either endothelial damage or accelerated turnover during vessel remodeling, but nothing is known about endothelial microparticles (EMPs) and other biomarkers reflecting endothelial alterations. This study aimed to document endothelial markers further according to the irreversibility of PAH secondary to CHD. The study investigated soluble markers of endothelial damage or activation (thrombomodulin, soluble endothelial protein C receptor, and soluble E-selectin), inflammation (interleukin-6), and angiogenic cytokine levels [vascular endothelial growth factor (VEGF) and placental growth factor (PlGF)] in 26 patients with CHD, 16 with reversible PAH (median age, 2 years) and 10 with irreversible PAH (median age, 9 years). Endothelial activation/apoptosis was evaluated by measuring EMP levels. Plasma procoagulant activity also was measured. The results show that the levels of soluble markers indicating endothelial activation were not predictors of PAH irreversibility. Lower levels of PlGF were observed in reversible compared with irreversible PAH but were not associated with the CEC level, the mean pulmonary artery pressure (mPAP), or age. No significant difference in procoagulant activity or EMP level was found between irreversible and reversible PAH. Among a large panel of biomarkers reflecting endothelial activation, regeneration, and injury, the high CEC levels previously described proved to be the only marker allowing discrimination between reversible and irreversible PAH secondary to CHD.

Lipopolysaccharide (LPS) is a highly proinflammatory molecule isolated from bacteria. This study demonstrated the existence of LPS in a medicinal fungus, Antrodia camphorata. Because no LPS had been identified in any fungus organism, the purification of LPS from A. camphorata was attempted. LPSs from six strains of A. camphorata (35396, 35398, 35716, B71, B85, and B86) were isolated. Chemical and functional properties were investigated on the fungus LPS. Compositional analysis revealed that sorbitol, fucose, galactose, and glucose were the neutral sugars in LPS of A. camphorata. Galactosamine, glucosamine, galactose, and glucose were the predominant monosaccharide species in E. coli O129 LPS molecules, whereas galactosamine and glucosamine were absent in A. camphorata LPS. Because these properties are different from those of bacterial LPS, the functions between fungus and bacterial LPS are also discussed. The vascular endothelial lining of blood vessels, which controls leucocyte traffic and activation, may be one of the primary targets of LPS action during sepsis. Assays for biological activity were performed on endothelial cells with anti-inflammatory effects associated with sepsis. A. camphorata LPS apparently showed a lesser extent of cytotoxicity than bacterial LPS. In contrary to the proinflammatory property of bacterial LPS, LPS from A. camphorata differentially reversed bacterial LPS-induced intercellular adhersion molecule-1 and monocyte adhesion; both were indicators during inflammatory process. In conclusion, basic chemical properties categorized A. camphorata extracts into lipopolysaccharide. However, the detailed functional structures and bioactivities of A. camphorata LPS were totally different from those of bacterial LPS. The investigation of the existence and anti-inflammatory effect of fungus LPS is at present a truly novel and important finding. These results show that LPS isolated from A. camphorata offers a novel therapeutic target for anti-inflammation against E. coli infection.

Neutrophil collagenase (matrix metalloproteinase-8 or MMP-8) is regarded as being synthesized exclusively by polymorphonuclear neutrophils (PMN). However, in vivo MMP-8 expression was observed in mononuclear fibroblast-like cells in the rheumatoid synovial membrane. In addition, we detected MMP-8 mRNA expression in cultured rheumatoid synovial fibroblasts and human endothelial cells. Up-regulation of MMP-8 was observed after treatment of the cells with either tumor necrosis factor-alpha (10 ng/ml) or phorbol 12-myristate 13-acetate (10 nM). Western analysis showed a similar regulation at the protein level. The size of secreted MMP-8 was 50 kDa, which is about 30 kDa smaller than MMP-8 from PMN. Conditioned media from rheumatoid synovial fibroblasts contained both type I and II collagen degrading activity. However, degradation of type II collagen, but not that of type I collagen, was completely inhibited by 50 microM doxycycline, suggesting specific MMP-8 activity. In addition, doxycycline down-regulated MMP-8 induction, at both the mRNA and protein levels. Thus MMP-8 exerts markedly wider expression in human cells than had been thought previously, implying that PMN are not the only source of cartilage degrading activity at arthritic sites. The inhibition of both MMP-8 activity and synthesis by doxycycline provides an incentive for further studies on the clinical effects of doxycycline in the treatment of rheumatoid arthritis.

1 The effects of exogenous guanosine 5'-triphosphate (GTP) and guanosine on vascular tone and cyclic nucleotide accumulation of noradrenaline-precontracted endothelium-intact and endothelium-denuded rat mesenteric artery rings were compared with the effects of the known purinoceptor agonists adenosine 5'-triphosphate (ATP) and adenosine.

Interaction of fibrin with endothelial cells through their receptor VE-cadherin has been implicated in modulation of angiogenesis and inflammation. Previous studies identified the VE-cadherin-binding site in the fibrin βN-domains formed by the NH2-terminal regions of fibrin β chains, and revealed that the recombinant dimeric (β15-66)2 fragment mimicking these domains preserves the VE-cadherin-binding properties of fibrin. To test if the other fibrin(ogen) regions/domains are involved in this interaction and localize the complementary fibrin-binding site in VE-cadherin, we prepared several recombinant fragments containing individual extracellular domains of VE-cadherin or combinations thereof, as well as several fragments corresponding to various fibrin(ogen) regions, and tested the interactions between them by ELISA and surface plasmon resonance. The experiments revealed that the βN-domains are the only fibrin(ogen) regions involved in the interaction with VE-cadherin. They also loc...