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This study aimed to assess endothelium-dependent vasomotor function in non-culprit coronary vessels in patients with recent acute coronary syndrome (ACS). Endothelial dysfunction can also concern peripheral vessels during ACS, but the frequency of this phenomenon at coronary circulation level is unknown. Endothelial function was assessed by infusion of graded doses of acetylcholine (ACh) in a non-culprit coronary artery of normal appearance in 43 patients having recently suffered from non-ST ACS, and reassessed 6 months later. Endothelium-dependent vasoreactivity was impaired at baseline in 81% (35/43) of the patients, and only 19% (8/43) of patients showed a normal response to ACh. Among the 35 subjects with initial dysfunction, 77% showed a significant improvement 6 months later. All patients without initial endothelial dysfunction remained normal. C-reactive protein (CRP) level was elevated at month 0, and had declined at follow-up, tending towards normal levels. At that time, apolipoprotein A-I (apoA-I) levels were correlated with vasomotor improvement in univariate (p0.02) and multivariate analysis (p0.04). In conclusion, endothelium dysfunction is very frequently observed after recent ACS in non-culprit and angiographically normal coronary arteries, and an improvement occurs within 6 months in most cases. After resolution of the initial inflammation, apoA-I seems to play an important role in endothelial function.

1. The rationale for preclinical research on the atheroprotective effect of oestrogens is based on the epidemiological evidence that women are protected against the clinical complications of atherosclerosis until menopause. However, this protection, probably due to sex hormones, is progressively lost within the years following menopause. 2. In addition, numerous studies have clearly demonstrated the atheroprotective effect of oestrogens in all animal models. 3. In the present paper, we first summarize our understanding of the pathophysiology of atherosclerosis. We then focus on the recognized target of oestradiol (E2) in the vessel wall: the classical target, namely the endothelium, and a recently characterized target, namely cells of the inflammatory-immune system. Finally, we discuss how unknown mechanisms in atherosclerosis could be responsible for the absence of effect of hormone-replacement therapy in the Heart and Estrogen/ progestin Replacement Study (HERS).

Introduction Estradiol (E2) binds to Estrogen Receptor alpha (ERα) activation functions (AF-1 and -2) and regulates gene transcription. A fraction of ERa is targeted to plasma membrane and elicits membrane-initiated steroid signalling (MISS) but its physiological role has never been directly investigated in vivo. Methods We thus generated a mouse mutated for the palmitoylation site (C451A-ERα) by homologous recombination, leading to an abrogation of membrane localization of ERα. Results Surprisingly, this single mutation leads to total female infertility with abnormal ovaries lacking corpus luteum and hence low progesterone production. However, E2 proliferative action was completely preserved in the uterus of C451A-ERa mutant mice and endometrial epithelial proliferation was similar to wild-type. On the opposite, E2 vascular effects, such as rapid dilatation, acceleration of endothelial healing and endothelial NO synthase phosphorylation were abrogated in arteries of C451A-ERa mice. In striking contrast, in mice inactivated for genomic effects (ERa-AF2°), acceleration of re-endothelialization using membrane-selective activator estrogen-dendrimer conjugate (EDC) was preserved, demonstrating the integrity of the MISS actions in ERa-AF2°. Using a large scale analysis of uterine gene expression, almost all uterine E2-dependent gene expression was abrogated in ERa-AF2°, whereas in C451A mice, gene regulation was essentially similar to wild-type, revealing that this uterine transcriptional response depends primarily on genomic/nuclear functions of ERα. Conclusion These models provide evidence for the first time of the physiological role of MISS effects of ERα in vivo and delineate tissue specific roles of membrane and nuclear actions of ERα.

Angiotensin-converting enzyme (ACE) is mainly responsible for converting angiotensin I (AI) to angiotensin II (AII), and ACE inhibitors prevent atherosclerosis in animal models. Neutral endopeptidase 24.11 (NEP) degrades substance P, kinins and atrial natriuretic peptide (ANP), and aortic wall NEP activity was found to be increased in atherosclerosis. In the present study, we have evaluated the effect of candoxatril, a NEP inhibitor, and of omapatrilat, a dual ACE and NEP inhibitor, on the development of fatty streak in apolipoprotein E (apoE)-deficient mice. Groups of ten male apoE-deficient mice were given either placebo, candoxatril 50 mg/kg per day, or omapatrilat 10, or 100 mg/kg per day for 4 months. None of the treatments influenced body weight, serum total or HDL-cholesterol. Compared with the placebo, candoxatril did not protect the mice from fatty streak deposit. In contrast, omapatrilat dose dependently inhibited the constitution of fatty streak in apoE-deficient mice. The precise advantages of the dual ACE and NEP inhibition versus the inhibition of only ACE should now be considered in the prevention of atherosclerosis as well as in the occurrence of its complications.

The epithelium of the paranasal sinuses produces nitric oxide (NO), which probably plays a major role in the nonspecific defense of these cavities through its bacteriostatic and cilia motility stimulation properties. Abundant eosinophils of nasal polyps potentially generate superoxide anion (O2-*), but NO and O2-* inactivate reciprocally. The purpose of the present work was to evaluate the relationship between NO concentrations and nasal polyp production of O2-*. Polyp fragments from 24 patients were studied using histological examination and lucigenin-enhanced chemiluminescence (to assess O2-* production). The effect of various concentrations of exogenous NO on chemiluminescent signals was assessed. Basal and phorbol ester-stimulated O2-* production varied largely among patients, but both were highly related to eosinophilic infiltration. A slow releasing NO donor DETA NONOate (DETA/NO NOC-18) dose dependently inhibited lucigenin-enhanced chemiluminescence from phorbol ester-stimulated polyp fragments, with an EC50 of 1.5 mM. The NO concentration in normal maxillary sinus was estimated about 10 ppm (i.e., 0.5 microM in aqueous phase) (Lundberg, et al. Nature Med 1995;1:370). Calculations revealed that the DETA NONOate 0.75 mM and 1.5 mM generate steady-state concentrations of NO of 0.5 microM and 2.5 microM, respectively. In conclusion, the NO concentration present in paranasal sinuses appears to partially suppress (approximately 20-40%) O2-* production from polyp eosinophils. Conversely, phagocytic-derived O2-* could contribute to decrease sinus NO concentration, further altering this natural local defense. Together, these events could participate in chronic inflammation and contribute to the pathophysiology of nasal polyps.

Endothelium produces oxygen-derived free radicals (nitric oxide, NOz.rad;; superoxide anion, O(2)(*-)) which play a major role in physiology and pathology of the vessel wall. However, little is known about endothelium-derived O(2)(*-) production, particularly due to the difficulty in assessing O(2)(*-) when its production is low and to controversies recently raised about the use of lucigenin-enhanced chemiluminescence. We compared four techniques of O(2)(*-) assessment when its production is low. In the present study, we have compared ferricytochrome c reduction, electron spin resonance (ESR) spectroscopy using DMPO as spin trap, hydroethidine fluorescence, and lucigenin-enhanced chemiluminescence to assess O(2)(*-) production in cultured bovine aortic endothelial cells (BAEC). We focused our study on extracellular O(2)(*-) production because the specificity of the signal is provided by the use of superoxide dismutase, and this control cannot be obtained intracellularly. We found that the calcium ionophore A23187 dose-dependently stimulated O(2)(*-) production, with a good correlation between all four techniques. The signals evoked by postconfluent BAEC were increased 2- to 7-fold in comparison to just-confluent BAEC, according to the technique used. Ferricytochrome c 20 microm rather than at 100 microm appears more suitable to detect O(2)(*-). However, in the presence of electron donors such as NADH or NADPH, lucigenin-enhanced chemiluminescence generated high amounts of O(2)(*-). Thus, ferricytochrome c reduction, electron spin resonance (ESR), and hydroethidine fluorescence appear as adequate tools for the detection of extracellular endothelium-derived O(2)(*-) production, whereas lucigenin may be artifactual, even when a low concentration of lucigenin is employed.

Abstract —It has previously been reported that hypertension induced by the chronic blockade of NO production is characterized by a proinflammatory phenotype of the arterial wall associated with a periarterial accumulation of inflammatory cells. In the present study, the cellular and molecular mechanisms involved in the luminal and perivascular accumulation of inflammatory cells were evaluated in the aortas of N G -nitro- l -arginine methyl ester (L-NAME)–treated rats. Because the medial layer remains intact, putative markers of the resistance of the vascular wall to cell migration and to oxidative stress were also explored. For this purpose, monocyte adhesion, cytokine expression, superoxide anion production, and nuclear factor-κB (NF-κB) activation were assessed in the aortas of L-NAME–treated rats. Expressions of tissue inhibitor of metalloproteinases-1 (TIMP-1) and heme oxygenase-1 (HO-1) in the aortic wall were also studied as possible markers of such resistance. Chronic blockade of NO production increased ex vivo monocyte adhesion to the endothelium, increased the production of superoxide anions, and activated the NF-κB system. In concert with this modification of the redox state of the vascular wall in L-NAME–treated rats, the expression of proinflammatory cytokines interleukin-6, monocyte chemoattractant protein-1, and macrophage colony–stimulating factor was increased. In parallel, expressions of both TIMP-1 and HO-1 were increased. All these changes were prevented by treatment with an angiotensin-converting enzyme inhibitor (Zofenopril). Hypertension associated with a proinflammatory phenotype of the vascular wall induced by blockade of NO production could be due to an increase in oxidative stress, which, in turn, activates the NF-κB system and increases gene expression. In parallel, the arterial wall overexpresses factors such as TIMP-1 and HO-1, which could participate in the resistance to cell migration and oxidative stress.

Asymmetric dimethyl-L-arginine (ADMA) is a naturally occurring analogue of L-arginine (L-Arg), the substrate of nitric oxide synthase (NOS). ADMA is a potent endogenous inhibitor of NOS and accumulates in the plasma of patients with renal failure, with peripheral arterial occlusive disease or with clinically asymptomatic hypercholesterolemia. We measured circulating concentrations of L-arginine, symmetric and asymmetric dimethylarginine (SDMA and ADMA, respectively) in human serum. We developed a new method for the rapid determination of these molecules using capillary electrophoresis and laser-induced fluorescence (CE-LIF). All methylated arginines were labeled with fluorescein isothiocyanate (FITC) prior to analysis. Under the capillary electrophoresis (CE) conditions used, methylated arginine derivatives were well separated, with a migration time of around 10 min. These migration times were smaller than the ones of other amino acids which do not have the same charge at pH 10. Consequently, such basic amino acids were well separated from most of the other amines or amino acids. Moreover, CE allowed one to separate all the analogues of fluorescein thiocarbamyl-arginine. The results indicated that CE-LIF is useful as a selective, rapid, cheap and sensitive tool for the determination of methylated arginine products. This new technology might appreciate the endogenous substrate for NO synthase and facilitate the knowledge of the physiological and pathophysiological regulation of NO synthesis.

Abstract —The recruitment of monocytes via the endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) is a key step in the formation of the initial lesion in atherosclerosis. Because angiotensin (Ang) II may be involved in this process, we investigated its role on the signaling cascade leading to VCAM-1 expression in endothelial cells. Ang II stimulates mRNA and protein expression of VCAM-1 in these cells via the AT 1 receptor. This effect was enhanced by N G -nitro- l -arginine methyl ester, a nitric oxide synthase inhibitor, and blocked by pyrrolidinedithiocarbamate, an antioxidant molecule. Ang II activated the redox-sensitive transcription factor nuclear factor-κB and stimulated the degradation of both inhibitor of κB (IκB)α and IκBβ with different kinetics. The degradation of IκBs induced by Ang II was not modified by incubation with exogenous superoxide dismutase and catalase, suggesting that this effect was not mediated by the extracellular production of O 2 − . In contrast, rotenone and antimycin, 2 inhibitors of the mitochondrial respiratory chain, inhibited the Ang II–induced IκB degradation, showing that generation of reactive oxygen species in the mitochondria is involved on Ang II action. BXT-51702, a glutathione peroxidase mimic, inhibited the effect of Ang II, and aminotriazole, an inhibitor of catalase, enhanced it, suggesting a role for H 2 O 2 in IκB degradation. This is confirmed by experiments showing that Ang II stimulates the intracellular production of H 2 O 2 in endothelial cells. These results demonstrate that Ang II induced an intracellular oxidative stress in endothelial cells, which stimulates IκB degradation and nuclear factor-κB activation. This activation enhances the expression of VCAM-1 and probably other genes involved in the early stages of atherosclerosis.

Inhaled nitric oxide (NO) is used to treat various cardiopulmonary disorders associated with pulmonary hypertension. The rationale is based on the fact that NO, given by inhalation, only dilates those pulmonary vessels that perfuse well-ventilated lung units. As a result, pulmonary gas exchange is improved while pulmonary vascular resistance is reduced and pulmonary blood flow is increased. Inhaled NO has been succesfully applied to treat persistent pulmonary hypertension of the newborn, reducing the need for extracorporeal life support. Although pulmonary hypertension and altered vasoreactivity contribute to profound hypoxaemia in adult and paediatric acute respiratory distress syndrome (ARDS), the benefit of inhaled NO still remains to be established in patients with ARDS. ARDS is a complex response of the lung to direct or indirect insults, leading to pulmonary vasoconstriction and various inflammatory responses. Recent randomized trials suggest that inhaled NO only causes a transient improvement in oxygenation. Whether this effect is important in the long-term management of ARDS remains to be established. NO, measured in the exhaled breath, is an elegant and non-invasive means to monitor inflammation of the upper and lower respiratory tract. In the normal upper airways, the bulk of exhaled NO originates from the paranasal sinuses. Exhaled NO is increased in nasal allergy and decreased in cystic fibrosis, nasal polyposis and chronic sinusitis. That NO production is increased in asthmatic airways is also well established. However, several questions still need to be addressed, in particular evaluation of the sensitivity and specificity of the measurement techniques, and assessment of the bronchodilator action of endogenous NO.

In normal upper airways, nitric oxide is generated by the paranasal sinus epithelium and then diffuses into the nasal cavities. This study examined whether or not nasal NO concentration is affected by paranasal sinus inflammatory diseases. The influence of obstruction (nasal polyposis) and/or inflammation (allergy or chronic sinusitis) of the paranasal sinuses on nasal NO concentration was evaluated in nasal allergic (n=7 patients) or nonallergic (n=20) polyposis, nonallergic chronic sinusitis (n=10) and Kartagener's syndrome (n=6) and compared with control subjects (n=42). A score of alteration of the paranasal sinus (number of altered and occluded sinuses) was determined by a computed tomography scan. The nasal NO concentration in nasal nonallergic polyposis (150+/-20 parts per billion (ppb)) was significantly decreased compared with both controls (223+/-6 ppb, p=0.01) and polyposis with allergy (272+/-28 ppb, p

Nitric oxide (NO) is a free radical gas and a short-lived messenger which has many paracrine functions. Direct assessment of NO production is very difficult in vivo. However, the paranasal cavities generate a high amount of NO which diffuses in the nasal cavity where it can be easily measured. Several studies have suggested alterations of the NO production in heart failure. Thus, we assessed nasal NO concentration in normal subjects and in heart failure patients. The nasal NO concentration averaged 227 +/- 10 ppb in the control group (n = 20), and 210 +/- 10, 198 +/- 20 and 159 +/- 54 ppb in New York Heart Association (NYHA) class II (n = 30), III (n = 28) and IV (n = 7) patients, respectively (mean +/- standard error [SE], not significant using analysis of variance [ANOVA]). Nasal NO level was not influenced by age, sex or etiology of the heart failure or by treatment with frusemide, angiotensin-converting enzyme inhibitor or digoxin. However, treatment with NO-releasing drugs (nitrates or molsidomine) significantly decreased the nasal NO level in heart failure patients. A two-way ANOVA revealed that treatment with a NO-releasing drug influenced nasal NO concentration (P = 0.0005), whereas NYHA class did not (P = 0.23), with a trend towards an interaction between the two parameters (P = 0.09): the inhibitory effect of NO-releasing drug on nasal NO concentration was more pronounced in severe heart failure. In an additional group of 12 patients (NYHA class II or III), the nasal NO concentration was 174 +/- 19 ppb during NO-releasing drug treatment and increased to 231 +/- 27 ppb 3 days after withdrawal of the nitrates (P = 0.0007 using paired t-test). Conversely, the nasal NO concentration in another group of seven patients (NYHA class II or III) was 219 +/- 32 ppb without nitrate treatment and decreased to 188 +/- 28 ppb 7 days after nitrate addition (P = 0.02 using paired t-test). In contrast, the nasal NO concentration in another group of ten ischemic patients without heart failure was 203 +/- 25 ppb without nitrate treatment and was similar (207 +/- 28 ppb) 7 days after nitrate addition (not significant using paired t-test). In conclusion, nasal NO production is normal in heart failure, except in patients receiving NO-releasing drugs. Nasal NO concentration could be useful for investigating the mechanism(s) by which exogenous NO donors decrease endogenous NO production.

Angiotensin II (ANG II) produces vasoconstriction by a direct action on smooth muscle cells via AT1receptors. These receptors are also present in the endothelium, but their function is poorly understood. This study was therefore undertaken to determine whether ANG II elicits the release of nitric oxide (NO) from cultured rat aortic endothelial cells. NO production, measured by the accumulation of nitrite and nitrate, was enhanced by 10−7M ANG II. The biological activity of the NO released by ANG II action was evaluated by measuring its guanylate cyclase-stimulating activity in smooth muscle cells. The guanosine 3′,5′-cyclic monophosphate (cGMP) content of smooth muscle cells was significantly increased by exposure of supernatant from ANG II-stimulated endothelial cells. These effects resulted from the activation of NO synthase, as they were inhibited by the l-arginine analogs. These ANG II actions were mediated by the AT1receptor, as shown by their inhibition by the AT1antagonist losartan. The cGMP production by reporter cells was inhibited by the calmodulin antagonist W-7, suggesting that ANG II activates endothelial calmodulin-dependent NO synthase. This hypothesis is also supported by the increase of intracellular free calcium induced by ANG II in endothelial cells. ANG II also stimulated luminol-enhanced chemiluminescence in endothelial cells. This effect was inhibited by Nω-monomethyl-l-arginine and superoxide dismutase, suggesting that this luminol-enhanced chemiluminescence reflected an increase in peroxynitrite production. Thus ANG II stimulates NO release from macrovascular endothelium, which may modulate the direct vasoconstrictor effect of ANG II on smooth muscle cells. However, this beneficial effect may be counteracted by the simultaneous production of peroxynitrite, which could contribute to several pathological processes in the vascular wall.

Abstract The reality of the atheroprotective effect of estrogens is still a matter of debate, and its unknown mechanisms could involve favorable changes in blood lipids and lipoproteins and/or direct action at the level of the arterial wall. We used the recently developed animal model of atherosclerosis constituted by apolipoprotein E–deficient mice in an attempt to clarify these issues. Male and female animals, fed a low-fat chow diet, were treated with increasing doses of 17β-estradiol (E 2 ) after castration and compared with testosterone treated and uncastrated (intact) animals. Total serum cholesterol, LDL-cholesterol, and HDL-cholesterol concentrations decreased under E 2 treatment in each sex and were weakly correlated with lesion area. However, a highly significant correlation between lesion area and serum E 2 levels also suggested a direct action of E 2 on cells of the vascular wall. A dose-response curve analysis revealed that these activities were sex-dependent, with females being nearly twice as sensitive to E 2 as males. It also revealed that the atheroprotective activity was recruited at higher E 2 concentrations than those needed by other E 2 target tissues such as uterus or functions such as apoA-1 and LDL production and/or clearance rates.

Physiological adaptation of normal blood vessels to acute or chronic changes in blood flow is endothelium dependent. In vitro studies have shown that, among other genes, NO synthase (NOS) 3 mRNA and protein expression is enhanced by acute elevation of shear stress in endothelial cells. We have investigated the effect of chronic high blood flow on NOS3 mRNA and protein expression in rat aorta. NOS3 mRNA levels were measured by quantitative polymerase chain reaction (PCR) in the aortas of 12 rats with arteriovenous fistulas and 9 sham-operated control rats. The PCR assay indicated that NOS3 mRNA levels were significantly enhanced (twofold) during high blood flow. Western blots showed that immunoreactive NOS3 levels were also increased to a similar extent. Furthermore, the Ca 2+ -dependent NOS activity, measured by the l -arginine to l -citrulline conversion assay, and the cGMP content were also significantly increased in the proximal aortic wall submitted to the arteriovenous shunt. These results indicate that NOS3 mRNA and protein expression is enhanced in vivo during chronic high blood flow.

The effect of extracellular L-arginine and L-glutamine on nitric oxide (NO) release was studied in cultured bovine aortic endothelial cells and in rabbit aortic rings. Increasing L-arginine (0.01 to 10 mM) did not alter NO release from cultured endothelial cells or modify endothelium-dependent relaxation to acetylcholine in isolated vessels. L-Glutamine (0.6 and 2 mM) inhibited NO release from cultured cells (in response to bradykinin) and from aortic rings (in response to acetylcholine or ADP). L-Arginine (0.1-10 mM) dose-dependently reversed the L-glutamine inhibition of receptor-stimulated NO release in both models. In contrast to its inhibitory response to receptor-mediated stimuli, glutamine alone slightly potentiated NO release in both models when the calcium ionophore, A23187, was added. Furthermore, cultured cells incubated with L-arginine (0.01-10 mM), in the presence or absence of glutamine, released similar amounts of NO in response to A23187. L-Glutamine did not affect intracellular L-arginine levels. Neither D-glutamine nor D-arginine affected NO release or endothelium-dependent vascular relaxation. L-Glutamine had no effect on the activity of endothelial NOS assessed by L-arginine to L-citrulline conversion. These findings show that in the absence of L-glutamine, manipulating intracellular L-arginine levels over a wide range does not affect NO release. L-Glutamine in concentrations circulating in vivo may tonically inhibit receptor-mediated NO release by interfering with signal transduction. One mechanism by which L-arginine may enhance NO release is via reversal of the inhibitory effect of L-glutamine, but apparently independently of enhancing NO synthase substrate.

It has been suspected that abnormalities of the L-arginine-nitric oxide pathway could underlie certain forms of hypertension. In this review, we will consider the role of nitric oxide in primary and secondary models of experimental hypertension and discuss potential abnormalities of the L-arginine-nitric oxide pathway in hypertension in humans.

N G -nitro- l -arginine methyl ester (L-NAME) and 11-desoxycorticosterone plus salt intake (DOCAsalt) hypertensive rat models were compared to study the possible involvement of model-specific factors in the development of renal angiopathy and left ventricular hypertrophy (LVH). Blood pressure was measured in L-NAME, DOCA-salt hypertensive, and control Wistar rats, and the lesions of nephroangiosclerosis and left ventricular hypertrophy were evaluated after 7 weeks. Arterial wall cyclic guanosine monophosphate, plasma renin activity (PRA), and renal renin storage were assessed in parallel. For the same level of hypertension in the two models, the renal arterial fibrinoid necrotic lesions were significantly more frequent in L-NAME than in DOCA-salt hypertensive rats. In DOCA-salt hypertensive rats, PRA was decreased and arterial cGMP increased compared to controls. In the L-NAME model, arterial cGMP decreased and PRA showed a bimodal distribution in this intermediate stage of hypertensive disease. LVH was observed in DOCA-salt rats and only in the L-NAME rats with a high level of PRA. There was a close correlation between the lesions of nephroangiosclerosis, left ventricular index, and plasma renin activity in L-NAME rats. We therefore suggest that the activation of the renin-angiotensin system participates specifically in the development of the second stage of hypertension during chronic blockade of NO synthase involving nephroangiosclerosis and LVH.

During the past two years, the enzyme responsible for production of endothelium-derived nitric oxide, the endothelial cell NO synthase (ecNOS) has been cloned and the gene encoding this enzyme isolated, cloned and its structure characterized. This research has provided direction for a variety of studies of regulation of the ecNOS. Several features of the ecNOS are compatible with a constitutively expressed, poorly regulated gene, including absence of a TATA box and numerous SP-1 sites. The promoter also contains a number of putative binding domains which suggest that it may be regulated by a variety of transcription factor mediated signals. In this review we will discuss evidence to support the concept that the ecNOS is a constitutively expressed gene subject to a modest degree of regulation by important physiological influences.

Introduction Les œstrogenes previennent l’accumulation de masse grasse et l’installation d’une insulinoresistance via leur recepteur α (ERα). Ce recepteur nucleaire est connu pour reguler la transcription de nombreux genes grâce a deux fonctions de transactivation, AF-1 et AF-2, et nous avons recemment montre que, en activant le recepteur independamment de la fonction AF-1, il est possible de conserver l’integralite des effets protecteurs des œstrogenes sur le metabolisme glucidique et la paroi vasculaire, sans effet deletere sur l’uterus. Materiels et methodes Pour determiner l’implication de la fonction AF-2 dans l’action benefique des œstrogenes sur la composition corporelle, la sensibilite a l’insuline et l’homeostasie glucidique, des souris deficientes en ERα (ERα−/−) ou specifiquement en AF-2 (AF-2°), ont ete etudiees en conditions de regime standard ou hyperlipidique (mâles et femelles, n = 8–10 par sexe et par genotype). Resultats Par comparaison a leurs controles sauvages, les souris ERα−/− et AF-2° sont caracterisees par une prise de poids acceleree avec accumulation massive de tissu adipeux, une insulinoresistance et une intolerance au glucose. Pour s’affranchir de l’effet potentiel des steroides sexuels endogenes, des souris femelles ovariectomisees ont ensuite recu une administration chronique de 17β- estradiol a doses physiologiques. Comme attendu, ce traitement previent l’exces d’adiposite, ainsi que l’alteration de la sensibilite a l’insuline (clamps hyperinsulinemiques, voie de signalisation de l’insuline dans les tissus peripheriques) et de la tolerance au glucose chez les souris sauvages, mais ces effets sont totalement abolis chez les souris ERα−/− et AF-2°. Conclusion Comme precedemment demontre concernant leurs effets vasculoprotecteurs, l’action benefique des œstrogenes sur l’adiposite, la sensibilite a l’insuline et la tolerance au glucose s’avere independante de la fonction AF-1, mais dependante de la fonction AF-2 du ERα. Ces resultats ouvrent la voie a une modulation selective du recepteur activant specifiquement AF-2 dans une perspective de prevention cardiovasculaire et metabolique.

BackgroundA fat-enriched diet favors the development of gram negative bacteria in the intestine which is linked to the occurrence of type 2 diabetes (T2D). Interestingly, some pathogenic gram negative bacteria are commonly associated with the development of periodontitis which, like T2D, is characterized by a chronic low-grade inflammation. Moreover, estrogens have been shown to regulate glucose homeostasis via an LPS receptor dependent immune-modulation. In this study, we evaluated whether diet-induced metabolic disease would favor the development of periodontitis in mice. In addition, the regulatory role of estrogens in this process was assessed.MethodsFour-week-old C57BL6/J WT and CD14 (part of the TLR-4 machinery for LPS-recognition) knock-out female mice were ovariectomised and subcutaneously implanted with pellets releasing either placebo or 17β-estradiol (E2). Mice were then fed with either a normal chow or a high-fat diet for four weeks. The development of diabetes was monitored by an intraperitoneal glucose-tolerance test and plasma insulin concentration while periodontitis was assessed by identification of pathogens, quantification of periodontal soft tissue inflammation and alveolar bone loss.ResultsThe fat-enriched diet increased the prevalence of periodontal pathogenic microbiota like Fusobacterium nucleatum and Prevotella intermedia, gingival inflammation and alveolar bone loss. E2 treatment prevented this effect and CD14 knock-out mice resisted high-fat diet-induced periodontal defects.Conclusions/significanceOur data show that mice fed with a diabetogenic diet developed defects and microflora of tooth supporting-tissues typically associated with periodontitis. Moreover, our results suggest a causal link between the activation of the LPS pathway on innate immunity by periodontal microbiota and HFD-induced periodontitis, a pathophysiological mechanism that could be targeted by estrogens.

The rat aorta, whose three wall layers can be separated by microdissection offers the rare possibility of comparing physiological characteristics of in vivo tissular cell components and corresponding cells after culture. We developed a technique allowing the dissociation of the three tunicae (intima, media and adventitia) of the rat aorta and the culture of their main cell types, i.e.: endothelial cells (EC) from intima, smooth muscle cells (SMC) from media and fibroblasts (Fib) from adventitia. Comparison between selected tunicae in vivo and their corresponding cells in vitro was performed via arterial angiotensin converting enzyme (ACE) activity measurements in Wistar rats. In vivo microsomial ACE activity for each tunica was as follows: 368.9 +/- 34.3 (endothelium), 10.5 +/- 1.9 (media) and 10.2 +/- 4.9 (adventitia) pmol/mg protein/min. Corresponding cell primary culture values were 1.2 +/- 0.1 (EC), 0.06 +/- 0.02 (SMC) and 0.24 +/- 0.01 (Fib) pmol/mg protein/min. Incubation of serum-deprived cells with Dexamethasone (10(-7) M) over 48 hr induced a statistically significant shift of total ACE activity from controls to stimulated cells of 2.9 +/- 0.3 to 9.7 +/- 1.0 in EC, 0.8 +/- 0.1 to 32.1 +/- 4.9 in SMC and 1.03 +/- 0.65 to 57.2 +/- 2.1 pmol/mg prot/min in fibroblasts. In the rat aorta, ACE was present not only in the intimal endothelial cell lining, but also in the media and the adventitia. ACE activity levels in primary cultured vascular cells were about 100-fold less than those found in the ex vivo tissues. Nevertheless, ACE expression seems to be more constitutive in endothelial cells and more inducible in smooth muscle cells and fibroblasts. This methodological approach should be of interest in studying environmental or genetic regulation of protein expression in the three layers/three cell types of the vascular wall.

International audience; Angiotensin I-converting enzyme (ACE) is known to be present at the surface of endothelial cells and also in the adventitia in large vessels. The presence of ACE in the vascular smooth muscle remains controversial. We microdissected segments of adventitia and media with or without endothelium from a region devoid of collateral arteries. The membrane-bound ACE activity in the media averaged 41% (pmol [glycine-1-14C]hippuryl-L-histidyl-L-leucine hydrolyzed.g tissue-1.min-1) of the values found in the whole aorta, whereas the adventitia contained only 6%. Immunoreactive ACE in media was characterized by Western blotting. ACE mRNAs were detected and characterized after polymerase chain amplification in isolated media. Angiotensin I and angiotensin II were equally able to contract medial rings, and the response to angiotensin I was blocked by enalaprilat. In aortas of two-kidney, one-clip hypertensive rats, there was an increase in ACE mRNA estimated by ribonuclease protection assay (P = 0.02) and in ACE activity at 15 days and 1 and 3 mo after clipping. This corresponded to a 1.5- to 2-fold increase in the ACE activity of both the media and the adventitia compared with sham-operated rats (P < or = 0.02). Thus ACE gene expression occurs in smooth muscle of rat aorta, which contains roughly the same amount of enzyme as the endothelium and readily converts angiotensin I to angiotensin II. ACE in the medial layer and the adventitia is upregulated in renovascular hypertension.

Nitric oxide, which is produced from L-ar-ginine by a nitric oxide-synthase enzyme, has been shown to be a ubiquitous messenger molecule. Recently, it has been suggested that nitric oxide might influence insulin secretion by activating the soluble guanylate cyclase and generating cyclic guanosine monophosphate (cGMP). We have investigated the role of the nitric oxide pathway in insulin secretion by evaluating the insulin response to several secretagogues in rats in which nitric oxide-synthase was chronically inhibited by oral administration of the L-arginine analogue, NG-nitro-L-arginine methyl ester (L-NAME). Blood pressure and aortic wall cGMP content were used as indices of nitric oxide-synthase blockade. Insulin secretion was evaluated after an intravenous bolus of D-glucose, L-arginine or D-arginine. Chronic L-NAME administration induced a 30% increase in blood pressure and a seven-fold drop in arterial cGMP content. Body weight, fasting plasma glucose and insulin were not influenced by L-NAME administration. First-phase insulin secretion (1 + 3 min) in response to glucose was not significantly different in L-NAME and control rats. The areas under the insulin curve were similar in both groups. Insulin secretion in response to D-arginine or L-arginine in L-NAME-treated and control rats were also similar. In conclusion, chronic nitric oxide-synthase blockade increases blood pressure and decreases aortic cGMP content, but does not alter insulin secretion in response to several secretagogues. Chronic oral administration of L-NAME in the rat provides an adequate animal model for studying the L-arginine nitric oxide-pathway.

Chronic hypertension is a major predisposing factor for stroke in humans. It has recently been shown that long-term inhibition of nitric oxide synthase activity causes a gradual time-dependent increase in arterial blood pressure in rats. We used this new animal model of chronic hypertension to study the occurrence and spatial features of infarcts in the central nervous system. Rats were treated with a nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester, dissolved in the drinking water at 50 mg/kg per day for 11 weeks. The brains and spinal cords of hypertensive rats with and without motion disturbances were processed for standard microscopic examination. Seventy-nine percent of the hypertensive rats showed motion dysfunctions, especially front leg paralysis, and/or died suddenly when their systolic blood pressure reached approximately 215 mm Hg after approximately 7 weeks of treatment. All of the hypertensive rats with stroke had spinal cord infarcts (90% at the cervical or cervicothoracic level) either alone or combined with brain lesions (30%). These structural alterations ranged from focal areas of pale, spongy tissue to large necrotic sites with vascular alterations, including thickened or fibrinoid degenerated vessel wall, macrophage invasion, and reactive astrocytes. Infarcts occurred in the central nervous system with a high incidence in the spinal cord of hypertensive rats in which nitric oxide synthase was chronically blocked. This location of the hypertensive neuropathologic sequelae contrasts with the model of stroke-prone spontaneously hypertensive rats. The results suggest that nitric oxide is a key factor in spinal cord arteriolar vasomotion and structure in rats.

We performed a double-blind, placebo-controlled study to determine whether oral enoximone would aid weaning dobutamine-dependent patients. Twenty-four patients 64 +/- 10 years, with an echocardiographic ejection fraction of 0.20 +/- 0.06, and receiving maximal therapy were studied. After failure of dobutamine weaning, a dobutamine infusion was set up at 10 micrograms.kg-1.min-1 for 48 h. Oral enoximone (100 mg t.i.d.) or placebo was added from D0 for the next 28 days, while the dobutamine dosage was progressively decreased after D4 and eventually stopped at D7. The patients were then followed-up for 21 days (i.e. until enoximone administration had continued for 28 days). In the placebo group, two patients suffered a relapse of congestive heart failure (CHF) before D4, six patients withdrew during dobutamine tapering (five with a relapse of CHF and one with septic shock) and two during follow-up (one with a relapse of CHF and one with sustained ventricular tachycardia). In the enoximone group, three patients withdrew during dobutamine tapering (two with a relapse of CHF, one with a cutaneous rash). Four patients on placebo and nine receiving enoximone could be weaned from dobutamine, P < 0.05. Echocardiographic LV ejection fraction significantly increased and Doppler-derived indexes of systolic function tended to increase when enoximone but not placebo was associated with dobutamine. Oral enoximone might be helpful in weaning patients with end-stage congestive heart failure from i.v. dobutamine.

The results of the Women’s Health Initiative, a randomized controlled primary prevention trial evaluating the risks and benefits of estrogen plus progestin in healthy postmenopausal women, were published in July 2002.1 After a mean of 5.2 years of follow-up, the data and safety monitoring board recommended cessation of the trial because the test statistic for invasive breast cancer exceeded the stopping boundary for this adverse effect and the global index statistic supported risks exceeding benefits. More surprisingly, this trial revealed that hormone replacement therapy (HRT) does not confer vasculoprotection, but even slightly increases the risk of a cardiovascular event early after the start of HRT. These results are quite similar to those reported concerning the effect of HRT in secondary prevention (Heart and Estrogen/Progestin Replacement Study [HERS, 1998]).2 These data clearly conflict with previous clinical observations and experimental studies. Indeed, the clinical rationale for these two large randomized controlled trials was based on the epidemiological evidence that women are protected against the clinical complications of atherosclerosis until menopause. However, this protection, probably attributable to sex hormones, is steadily lost within the years after menopause. In addition, all experimental studies that use animal models of atherosclerosis, by feeding monkeys, swine, or rabbits an atherogenic diet,3 have clearly demonstrated that estrogens prevent fatty streak deposit, the first step of atherosclerosis. More recently, the effect of estrogens was also studied in genetically modified mice, which allowed evaluation of the expression of various genes in physiological or various pathophysiological processes. Mice deficient in apolipoprotein E demonstrate an endogenous hypercholesterolemia on a chow diet and …

Rationnel Les œstrogenes previennent l’accumulation de masse grasse et la survenue d’un diabete de type 2 via leur recepteur α(ERα), mais leurs effets indesirables limitent leur interet therapeutique. ER_regule la transcription de nombreux genes grâce a ses deux fonctions de transactivation, AF-1 et AF-2, et nous avons montre que, en activant le recepteur independamment de la fonction AF-1, il est possible de conserver l’integralite des actions vasculoprotectrices des oestrogenes sans effet deletere sur l’uterus. Materiels et methodes Pour etudier l’implication des fonctions de transactivation de ER_dans l’action benefique des oestrogenes sur la composition corporelle et l’homeostasie glucidique, des souris deficientes en ERα(ERα-/-), en AF-1 (AF-1-/-) ou AF-2 (AF-2-/-), ont ete suivies jusqu’a l’âge de 7 mois (regime standard, mâles et femelles, n = 8–10 par sexe et par genotype). Resultats Par comparaison a leurs controles sauvages, les souris ERα-/- ont ete caracterisees par une prise de poids acceleree avec accumulation massive de tissu adipeux, une insulinoresistance et une intolerance au glucose. Les souris AF-2-/- ont developpe un profil phenotypique et metabolique identique. En revanche, nous n’avons pas observe d’acceleration du gain ponderal et du developpement de la masse grasse chez les animaux AF-1-/-. De plus, la tolerance au glucose etait conservee chez les mâles, et alteree uniquement tardivement chez les femelles AF-1-/-. De facon concordante, l’effet protecteur de l’administration chronique de 17β-estradiol vis-a-vis de l’accumulation de tissu adipeux chez des femelles ovariectomisees etait aboli chez les souris ERα-/- et AF-2-/-, mais totalement conserve chez les souris AF-1-/-. Conclusion Comme pour leurs effets vasculoprotecteurs, l’action favorable des oestrogenes sur la masse grasse et la tolerance au glucose est en grande partie independante de la fonction AF-1 du ERα. Ces resultats ouvrent la voie a une modulation selective du recepteur n’activant pas AF-1 dans une perspective de prevention cardiovasculaire et metabolique.

Full length 66 kDa estrogen receptor alpha (ER) stimulates target gene transcription through two activation functions (AF), AF-1 in the N-terminal domain and AF-2 in the ligand binding domain. Another physiologically expressed 46 kDa ER isoform lacks the N-terminal A/B domains and is consequently devoid of AF-1. To evaluate the involvement of ER AF-1 and AF-2 in the vasculoprotective actions of estradiol (E2), we generated a targeted deletion of the ER A/B domain in the mouse named ERAF-10 mice, and a targeted deletion of amino acids 543–549 and thus deficient in AF-2 (named ERAF-20 mice). Both basal endothelial NO production was increased by E2 administration in a similar extent than in control mice. E2 similarly decreased fatty streak deposits at the aortic root from both ovariectomized 18 week-old ERAF-1+/+ LDL-r-/- (Low Density Lipoprotein receptor) and ERAF-10 LDL-r-/- mice fed with a hypercholesterolemic diet. We conclude that ER AF-1 is not required for the vasculoprotective actions of E2, whereas it is necessary for the effects of E2 on its reproductive targets. Thus, Selective Estrogen Receptor Modulators stimulating ER independently of the A/B domain and thereby with minimal activation of ER AF-1 could retain beneficial vascular actions, while minimizing the sexual effects. The results concerning ERAF-20 mice are in process and will be available at the end of 2010, and the precise role of AF2 in these actions will be presented.

Wistar rats given a nitric oxide synthase inhibitor, NG-nitro-L-arginine-methyl ester (L-NAME), for 4 weeks develop time- and dose-dependent hypertension without cardiac hypertrophy. This initial study of the relation between left ventricular weight and L-NAME-induced hypertension has now been extended by giving 50 mg/kg per day L-NAME to Wistar rats (n = 30) for 8 weeks and comparing results with those from control rats (n = 10) and two-kidney, one clip rats (n = 14). Although L-NAME rats and two-kidney, one clip rats had increased systolic blood pressures during the last 3 weeks of the experiment (202 +/- 24 and 224 +/- 16 mm Hg, respectively), the ratio of left ventricular weight to body weight of L-NAME rats (2.12 +/- 0.32 mg/g) was not statistically different from that of control rats (1.93 +/- 0.13 mg/g), whereas that of two-kidney, one clip rats was increased (2.85 +/- 0.20 mg/g). The plasma renin activity of L-NAME rats was not significantly different from that of control rats. Two L-NAME rat subgroups were defined according to the presence of left ventricular hypertrophy (ratio of left ventricular weight to body weight > 2.19 mg/g, control mean +2 SD) (6 of 25) or its absence (19 of 25). Systolic blood pressure, plasma renin activity, and cardiac angiotensin converting enzyme activity of L-NAME rats with left ventricular hypertrophy were significantly higher than those of the subgroup without.(ABSTRACT TRUNCATED AT 250 WORDS)

OBJECTIVE A decreased responsiveness to endothelium-dependent vasodilatory substances is characteristically seen in isolated arteries from spontaneously hypertensive rats (SHR). However, the precise status and role of nitric oxide (NO), which is, at least in part, the endothelium-derived relaxing factor, remains unclear in SHR. The objective of the present study was to evaluate the importance of NO release in vivo. METHODS The effect on systolic blood pressure of chronic administration of NG-nitro-L-arginine methyl ester (L-NAME, an NO-synthase inhibitor) was studied. Twenty SHR and 10 Wistar-Kyoto (WKY) rats were given 25 mg/kg per day L-NAME by gavage. Thirteen SHR and 14 WKY rats given water for the same period were used as controls. Rats were killed after 15 days and the aortic wall cyclic GMP (cGMP, the second messenger of NO) and cGMP-dependent kinase (the effector of cGMP) concentrations were assessed. RESULTS During the trial, 11 of the 20 SHR given L-NAME died. Mean +/- SD systolic blood pressure increased from 131 +/- 8 to 171 +/- 10 mmHg in WKY rats given L-NAME and from 185 +/- 10 to 249 +/- 22 mmHg in SHR given L-NAME. Aortic cGMP content was similar in control WKY rats (2122 +/- 707 fmol/mg protein) and in control SHR (2098 +/- 704 fmol/mg protein), and was decreased in the L-NAME-treated WKY rats and SHR to 308 +/- 87 and 644 +/- 222 fmol/mg protein, respectively. The aortic concentrations of cGMP-dependent kinase were not different in any group. CONCLUSIONS Basal release of NO does not appear to be impaired in SHR, but represents a major counter-regulatory mechanism in this genetic model of arterial hypertension.

Atrial natriuretic factor (ANF) promotes natriuresis and diuresis, increases vascular permeability and may induce p]ripheral vasodilation. Endothelium-derived relaxing factor (EDRF), which is nitric oxide (NO), promotes local vasodilatation. ANF and EDRF-NO both cause vascular relaxation by generating cGMP via the activation of the particulate and soluble guanylate cyclases, respectively. This study examines the in vivo effect exogeneous ANF administration in normal Wistar rats, and of increased endogenous ANF in an experimental model of heart failure, on plasma and tissue cGMP concentrations. Low-dose ANF increased plasma and pulmonary cGMP concentrations, whereas 10-fold higher doses were necessary to increase aorta cGMP concentrations. Rats with a myocardial infarction had increased plasma ANF and cGMP and pulmonary cGMP concentrations, but aorta cGMP concentration remained similar to that of sham-operated rats. NG nitro L-arginine methyl ester (L-NAME) was administered chronically to sham-operated and myocardial infarction rats to block NO-synthase: soluble guanylate cyclase activity. L-NAME did not lower the increase in plasma ANF concentration or in urinary, plasma or pulmonary cGMP concentration. In contrast, L-NAME reduced the aorta cGMP concentration 6-fold, despite an increased level of circulating ANF. In summary, the pathophysiological range of plasma ANF concentrations greatly increases plasma and pulmonary cGMP concentrations (by activating particulate guanylate cyclase), but has little influence on the aorta cGMP concentration (which remains mainly dependent on NO-synthase: soluble guanylate cyclase activity).

Arterial hypertension is accompanied mainly by trophic alterations in the structure of the arterial wall, such as changes in media thickness, increased collagen, loss of elastin and intimal proliferation. These changes are the result of phenotypic alterations in the smooth muscle cells. They are regulated by hemodynamic signals, blood and interstitial-borne signals, and signals from the endothelial cells. They produce alterations in the intracellular second messenger systems, and these transmit the information required to modify gene expression and thus the cell phenotype.

Dendritic cells (DC) are critical actors in the initiation of primary immune responses and regulation of self-tolerance. The steroid sex hormone 17β-estradiol (E 2 ) has been shown to promote the differentiation ofDCs from bone marrow (BM) precursors in vitro. However, the estrogen receptor (ER) involved in this effect has not yet been characterized. Using recently generated ERa- or ERβ-deficient mice, we investigated the role of ER isotypes in DC differentiation and acquisition of effector functions. We report that estrogen-dependent activation of ERa, but not ERβ, is required for normal DC development from BM precursors cultured with GM-CSF. We show that reduced numbers of DCs were generated in the absence of ERa activation and provide evidence for a cell-autonomous function of ERa signaling in DC differentiation. ERa-deficient DCs were phenotypically and functionally distinct from wild-type DCs generated in the presence of estrogens. In response to microbial components, ERa-deficient DCs failed to up-regulate MHC class II and CD86 molecules, which could account for their reduced capacity to prime naive CD4 + T lymphocytes. Although they retained the ability to express CD40 and to produce proinflammatory cytokines (e.g., IL-12, IL-6) upon TLR engagement, ERa-deficient DCs were defective in their ability to secrete such cytokines in response to CD40-CD40L interactions. Taken together, these results provide the first genetic evidence that ERa is the main receptor regulating estrogen-dependent DC differentiation in vitro and acquisition of their effector functions.

Estrogens are known to modulate lower urinary tract (LUT) trophicity and neuronal nitric oxide synthase (nNOS) expression in several organs. The aim of this study was to explore the effects of endogenous and supraestrus levels of 17β-estradiol (E2) on LUT and urethral nNOS expression and function. LUT function and histology and urethral nNOS expression were studied in adult female mice subjected either to sham surgery, surgical castration, or castration plus chronic E2 supplementation (80 μg·kg−1·day−1, i.e., pregnancy level). The micturition pattern was profoundly altered by long-term supraestrus levels of E2 with decreased frequency paralleled by increased residual volumes higher than those of ovariectomized mice. Urethral resistance was increased twofold in E2-treated mice, with no structural changes in urethra, supporting a pure tonic mechanism. Acute nNOS inhibition by 7-nitroindazole decreased frequency and increased residual volumes in ovariectomized mice but had no additive effect on the micturition pattern of long-term supraestrus mice, showing that long-term supraestrus E2 levels and acute inhibition of nNOS activity had similar functional effects. Finally, E2 decreased urethral nNOS expression in ovariectomized mice. Long-term supraestrus levels of E2 increased urethral tone through inhibition of nNOS expression, whereas physiological levels of E2 had no effect.

Objectif Bien que plusieurs arguments epidemiologiques et experimentaux plaident en faveur du benefice des œstrogenes vis-a-vis de la survenue d’une insulino-resistance et/ou d’un diabete de type 2, les mecanismes responsables de cet effet protecteur restent incertains. Le systeme immuno-inflammatoire etant une cible privilegiee des œstrogenes, leur effet metabolique favorable pourrait s’expliquer par la modification de la reponse inflammatoire induite par un stress nutritionnel. Pour valider cette hypothese, nous avons etudie l’influence des œstrogenes endogenes et exogenes chez des souris C57Bl/6 femelles soumises a un regime diabetogene hyperlipidique pendant 1þmois ou 3 mois. Resultats Nous avons confirme dans ce modele murin l’effet protecteur des œstrogenes endogenes (souris non ovariectomisees) et exogenes (administration s.c. Continue de 17β-œstradiol, E2, 80 μg/kg/j, chez des souris ovariectomisees) par comparaison a des souris ovariectomisees non traiteesþ: reduction de la prise ponderale, ameliorations significatives de la glycemie a jeun, de la tolerance au glucose et de la sensibilite a l’insuline (clamp euglycemique). De facon paradoxale, cet effet metabolique benefique s’accompagne de l’elevation concomitante de l’expression de plusieurs marqueurs inflammatoires au niveau du tissu adipeux visceral (IL-1b, IL-6, TNFa, PAI-1) et du foie (IL-6, PAI-1). Afin de determiner si l’effet inflammatoire des œstrogenes contribue a leur effet protecteur, des souris C57Bl/6 ont ete ovariectomisees, puis ont recu une irradiation letale suivie d’une greffe de moelle osseuse provenant de souris deficientes en recepteur α des œstrogenes. Tandis que l’effet pro-inflammatoire de l’E2 est aboli dans ce modele de chimeres hematopoietiques, l’effet protecteur metabolique de l’hormone est entierement maintenu. Enfin, cet effet protecteur est egalement conserve chez des souris deficientes en CD14 qui presentent une reponse inflammatoire tres attenuee en reponse au regime hyperlipidique. Conclusion Bien que favorisant l’expression de cytokines pro-inflammatoires au niveau du tissu adipeux visceral et du foie, les œstrogenes exercent un effet metabolique protecteur dans un contexte de stress nutritionnel, en preservant la sensibilite a l’insuline et la tolerance au glucose.

We compared the determination of plasma renin activity (PRA) and the direct immunoradiometric measurement of active renin (AR) as ways of assessing the activity of the renin-angiotensin system in normal volunteers and in patients with hypertension, heart failure, or liver failure. The levels of plasma renin substrate, angiotensinogen, and the ratio of PRA to AR concentration did not differ in the normal volunteers and the patients with essential or renovascular hypertension. However, compared to the volunteers, patients with severe heart or liver failure had markedly reduced plasma renin substrate levels, which led to a considerable underestimation of AR concentration when it was measured by PRA.

Le processus d’Aide Budgetaire Globale (MDBS) est ne au Ghana entre 2002 et 2003. Il repose sur l’adoption commune d’un cadre de performance entre le gouvernement du Ghana et dix bailleurs de fonds. Une revue annuelle permet a ces derniers de verser au budget de l’Etat environ 350 millions de dollars repartis entre une tranche de base et une tranche de performances. Apres deux annees pilotes inspirees pour partie d’experiences similaires dans d’autres pays tout en tenant compte des specificites ghaneennes, les membres du MDBS ont tire partie de mise en œuvre de la Declaration de Paris pour profondement reformer le processus de facon totalement conjoint en l’ancrant davantage sur le dialogue sectoriel, lequel a ete singulierement renforce a cette occasion, et en augmentant sensiblement la previsibilite des flux d’aide. Ceci s’est traduit in fine par une reduction sensible des couts de transaction, pour le gouvernement du Ghana - qui en a globalement beneficie des la mise en œuvre du MDBS - comme pour les bailleurs de fonds.