Mechanisms involved in the reduced leukocyte migration in intrauterine undernourishment.

OBJECTIVE: We investigated factors that may be involved in the reduced leukocyte migration observed in intrauterine undernourished rats. METHODS: Male Wistar rat offspring (8-9 wk of age) of dams fed during pregnancy with 50% less food than control dams were used to measure L-selectin expression (by flow cytometry), bone marrow cell count, blood cell count, laminin and type IV collagen in the basal membrane of venules of the spermatic fascia (by immunohistochemistry), total protein level and serum albumin, and the production of leukotriene B4 after stimulation with tumor necrosis factor-alpha and corticosterone plasma levels (by enzyme-linked immunosorbent assay). RESULTS: Hypocellularity in bone marrow and peripheral blood and reduced L-selectin expression were found in the undernourished rat offspring (UR) compared with nourished offspring (NR; P < 0.05). Type IV collagen in the basal membrane of the venules of the spermatic fascia was less in UR than in NR (P < 0.05). The total protein levels and serum albumin did not differ between the two groups. Leukotriene B4 production after stimulation with tumor necrosis factor-alpha was lower in UR (P < 0.05). These differences could not be attributed to circulating glucocorticoids levels, which were not different in the NR and UR groups. CONCLUSION: Our data suggest that all observed differences contribute to reduced leukocyte migration in undernourishment.

Role of the kallikrein-kinin system in Ang-(1-7)-induced vasodilation in mesenteric arterioles of Wistar rats studied in vivo-in situ.

Angiotensin-(1-7) [Ang-(1-7)], exerts a variety of actions in the cardiovascular system, with an important effect being vasodilation. In this work, we investigated the relationship between the vasodilatory activity of Ang-(1-7) and the kallikrein-kinin system. Intravital microscopy was used to study the vasodilation caused by Ang-(1-7) in the mesenteric vascular bed of anesthetized Wistar rats. The topical application of Ang-(1-7) caused vasodilation of mesenteric arterioles that was reduced by A-779, JE 049 and peptidase inhibitors (aprotinin, SBTI, PKSI 527, E-64, PMSF). These results indicated that the vasodilation induced by Ang-(1-7) in the mesenteric arterioles of Wistar rats was heavily dependent on the activation of kallikrein and subsequent kinin formation.

Considerações sobre o significado e o manuseio da intolerância a glicose em pacientes admitidos com síndrome coronária aguda / Hyperglycaemia: role and treatment in acute coronary syndrome patients

A doença cardiovascular é a principal causa de morte no mundo. Pacientes diabéticos têm risco aumentado para doença arterial coronária e apresentam elevada taxa de mortalidade no infarto do miocárdio, mesmo com evolução no tratamento. Também é relatada freqüência aumentada de complicações pós-infarto: insuficiência cardíaca, re-infarto, distúrbios de condução e arritmias. É comum a presença de hiperglicemia em pacientes críticos internados em unidades de terapia intensiva e unidades coronárias. Na síndrome coronária aguda, a hiperglicemia, seja ela na admissão ou durante o jejum, está presente em 30 por cento dos casos, independente do estado metabólico prévio. Discutiremos aqui a influência da hiperglicemia na evolução dos pacientes em fase aguda da doença coronária e quais são as recomendações para o seu manejo terapêutico

Losartan attenuates the antimigratory effect of diclofenac in spontaneously hypertensive rats.

Many patients with hypertension, particularly elderly patients, take nonsteroidal antiinflammatory drugs (NSAIDs) and antihypertensive agents. However, few studies describe the effect of the association of antihypertensive agents with NSAIDs on inflammatory response in hypertension. To investigate this, spontaneously hypertensive rats (SHRs) were treated with either diclofenac alone or diclofenac combined with losartan (an AT1 angiotensin II antagonist). The leukocyte-endothelial interaction was then observed using intravital microscopy. Blood pressure of SHR (169.6+/-3.6) was increased by diclofenac (186.4+/-2.9), reduced by losartan (152.6+/-3.5), and reduced by the combination of the 2 (158.9+/-3.7). All the treatments tested reduced the number of rollers, adherent and migrated leukocytes, and the expression of endothelial intercellular adhesion molecule-1 and P-selectin. The association of losartan reduced the effect of diclofenac on leukocyte migration. Neither treatment tested increased the venular shear rate or modified the venular diameters, number of circulating leukocytes, and L-selectin expression on granulocytes. The reduction of CD11/CD18 expression induced by diclofenac alone was hindered by losartan. A pharmacokinetic interference between losartan and diclofenac was ruled out since no significant differences were observed in the plasma concentrations of each drug when they were associated. In conclusion, although diclofenac does not interfere with the losartan antihypertensive effect, losartan attenuates the effect of diclofenac has on leukocyte behavior and expression of adhesion molecules. Losartan has an antimigratory effect, reducing leukocyte migration by reducing ICAM-1 and P-selectin expression. Losartan may hinder the full expression of the antimigratory effect of diclofenac.

Intrauterine undernutrition in rats interferes with leukocyte migration, decreasing adhesion molecule expression in leukocytes and endothelial cells.

Experimental and epidemiologic data have shown that malnutrition predisposes individuals to infections. Immune responses are compromised, particularly in undernourished children. Therefore, we investigated the migratory capacity of leukocytes, using the intravital microscopy technique, in male Wistar rats (8-9 wk of age) that were undernourished in utero after their dams were fed 50% less food than the amount consumed by control dams. The number of leukocytes rolling along the venular endothelium, sticking after stimulation with leukotriene B4, tumor necrosis factor-alpha (TNF-alpha) or zymosan-activated plasma, or migrating after TNF-alpha stimulation was significantly reduced in the undernourished rat offspring. Compared with nourished rat offspring, undernourished offspring had significantly reduced numbers of circulating leukocytes, higher blood pressure, and higher leukocyte rolling velocity (V(WBC)), as well as a higher ratio between V(WBC) and RBC velocity (V(RBC)). Endothelial P-selectin and intercellular adhesion molecule-1 (ICAM-1) expression, analyzed by immunohistochemistry, and basal leukocyte L-selectin expression, analyzed by flow cytometry, were significantly reduced in the undernourished rat offspring. Because the groups did not differ in leukocyte CD11/18 expression, endothelial expression of platelet-endothelial cell adhesion molecule-1, or venular blood flow velocity and, consequently, venular shear rate, we conclude that intrauterine undernutrition in rats reduces leukocyte migration, downregulates endothelial expression of P-selectin and ICAM-1, as well as leukocyte expression of L-selectin, while reducing leukocyte counts. The higher V(WBC) and V(WBC)/V(RBC) ratio may also play a role in this reduced leukocyte migration. Our data suggest that this phenomenon is involved in the increased predisposition to infections in undernourished subjects.

Aspectos farmacológicos da interação anti-hipertensivos e antiinflamatórios não-esteróides / Pharmacological aspects of the interaction antihypertensive and anti-inflammatory drugs

O uso da associação de antiinflamatórios (AINEs) e antihipertensivos é relativamente comum, principalmente em indivíduos idosos. A inibição da ciclooxigenases (COX-1 e 2), enzimas responsáveis pela síntese de prostaglandinas (PGs), é geralmente considerada como o principal mecanismo da ação dos AINEs. Os efeitos benéficos desses agentes têm sido explicados pela inibição da COX-2, induzível nos sítios inflamatórios, e seus efeitos colaterais por inibição da COX-1 constitutiva. As PGs são importantes na proteção da mucosa gástrica, na modulação da dilatação vascular renal e sistêmica, na secreção tubular de sódio e água, na neurotransmissão adrenérgica e no sistema renina-angiotensina-aldosterona. Muitos AINEs provocam elevação da pressão arterial e podem antagonizar parcial ou totalmente os efeitos de muitos anti-hipertensivos. Interações significativas ocorrem em cerca de 1 por cento de pacientes por ano. O risco é maior em idosos, afrodescendentes e em pacientes com hipertensão arterial com renina baixa. Os AINEs podem bloquear os efeitos antihipertensivos dos diuréticos tiazídicos e de alça, os antagonistas de receptores alfa e dos receptores beta-adrenérgicos, bem como os agentes que inibem o sistema renina-angiotensina-aldosterona. Não se detectou interação com agonistas alfa-adrenérgicos de ação central ou com bloqueadores de canais de cálcio. O uso de inibidores seletivos da COX -2 parece diminuir o risco de efeitos gastrintestinais graves. Entretanto, há dados mostrando aumento do risco de eventos cardiovasculares isquêmicos. Estudos clínicos demonstraram que, à semelhança dos AINEs não-seletivos, os inibidores seletivos da COX-2 podem induzir ou agravar hipertensão arterial já existente

Efeitos farmacológicos dos diuréticos e dos bloqueadores dos canais de cálcio / Pharmacological effects of diuretics and calcium channel blockers

Os diuréticos têm sido utilizados no tratamento de pacientes hipertensos durante as últimas quatro décadas. São tão eficazes quanto a maioria de outros agentes anti-hipertensivos. Administrados como monoterapia ou em associação com outros agentes, formam a base terapêutica para a maioria dos pacientes hipertensos. Os tiazídicos são usualmente os de primeira escolha, geralmente em associação com outras drogas anti-hipertensivas. Os diuréticos de alça são indicados para pacientes com insuficiência renal, hipertensão resistente ou falência cardíaca. Os diuréticos são prescritos para pacientes hipertensos principalmente por: (1) sua eficácia, baixo custo e poucos efeitos colaterais; (2) seu efeito sinérgico, quando em associação com outros agentes anti-hipertensivos; (3) impedir a retenção de sal e fluido causado por outros agentes anti-hipertensivos e (4) sua utilidade em pacientes com falência cardíaca. Os bloqueadores de canais de cálcio (BCC) constituem um grupo estrutural e funcionamento heterogêneo, e são freqüentemente usados no tratamento de pacientes com hipertensão e angina. Incluem as dihidropiridinas, como a nifedipina e o anlodipino e as não-dihidropiridinas como o verapamil e o diltiazem. Como classe são bem tolerados e exibem poucos efeitos colaterais. Apesar da preocupação com a segurança no seu uso, dados recentes de ensaios clínicos, em larga escala, não demonstraram associação dos BCC de longa duração e os eventos cardiovasculares. Mesmo assim o uso dos BCC foi associado a aumento do risco de falência cardíaca. A partir desses resultados, pode-se concluir que os BCC de longa duração podem ser usados no tratamento da hipertensão e angina. Entretanto, como classe não são tão protetores quanto os outros agentes anti-hipertensivos na falência cardíaca

A lower ratio of AT1/AT2 receptors of angiotensin II is found in female than in male spontaneously hypertensive rats.

OBJECTIVE: Sexual dimorphism has been observed in arterial hypertension. Blood pressure levels are lower in female than in male spontaneously hypertensive rats (SHR). Angiotensin II (Ang II) plays a major role in the regulation of blood pressure. The aim of this study was to compare Ang II vascular reactivity and AT(1) and AT(2) receptor gene expression in female and male SHR. METHODS: SHR animals were divided into four groups: (I) male, (II) female in physiological estrus, (III) ovariectomized and (IV) ovariectomized treated with estrogen. Arterial blood pressure, AT(1) and AT(2) mRNA expression were determined. Ang II responses in aorta and mesenteric vessels were also evaluated. RESULTS: In female SHR, aorta and mesenteric microvessels were hyporeactive to Ang II in comparison to male SHR. In ovariectomized females, Ang II vasoconstriction was similar to that of males. Estrogen treatment abolished this difference. The mRNA expression for AT(1) was higher in aorta and mesenteric vessels from males than in females. In ovariectomized SHR, mRNA expression for AT(1) was comparable to that of males. Treatment with estrogen reversed the over expression observed. Whereas AT(2) gene expression did not differ, a lower ratio AT(1)/AT(2) was found in female than in male vessels. A higher mRNA expression for AT(1) was observed in kidney from male than in female. Ovariectomy resulted in up-regulation of this subtype receptor. Treatment with estrogen reversed the overexpression. AT(2) gene expression was higher in kidney from female than male SHR. Ovariectomy reduced AT(2) gene expression and estrogen treatment reversed the alteration observed in kidney. CONCLUSION: There is sexual dimorphism in vascular reactivity and in receptor gene expression to Ang II in SHR. We conclude that estrogen modulates AT(1) and AT(2) receptor gene expression and that this might explain at least partially the lower blood pressure observed in female SHR.

ETA receptor mediates altered leukocyte-endothelial cell interaction and adhesion molecules expression in DOCA-salt rats.

Leukocyte adhesion to endothelial cells plays a key role in inflammatory processes associated with end-organ injury. Endothelin-1 (ET-1), which stimulates inflammatory processes, contributes to cardiovascular damage in deoxycorticosterone (DOCA)-salt hypertension. We investigated whether ETA receptor blockade modulates in vivo leukocyte-endothelial cell interactions and expression of cell adhesion molecules (CAM) involved in these processes. DOCA-salt and control uninephrectomized rats were treated with the ETA antagonist BMS182874 (40 mg/kg per day) or vehicle. Analysis of CAMs expression by reverse transcription-polymerase chain reaction and immunohistochemistry showed increased cardiac platelet selectin (P-selectin), detected mainly in endothelial cells, and vascular cell adhesion molecule-1 (VCAM-1), but not intercellular adhesion molecule-1 (ICAM-1), in DOCA-salt rats. Cardiac expression of endothelial selectin (E-selectin) was decreased, whereas immunoreactivity to ED-1 and myeloperoxidase (MPO) activity, markers of macrophage and leukocyte infiltration, respectively, were increased in DOCA-salt. Leukocyte-endothelial cell interaction, functionally assessed in venules of internal spermatic fascia by intravital microscopy, was significantly altered in DOCA-salt rats as evidenced by increased leukocyte adhesion and decreased rolling. BMS182874 treatment normalized leukocyte-endothelium interactions, decreased cardiac VCAM-1 expression in DOCA and control groups, and had no effects on ICAM-1 expression. BMS182874 also increased E-selectin and abolished P-selectin expression in DOCA-salt, but not in control rats. The ETA antagonist reduced cardiac ED-1 content and MPO activity and prevented cardiac damage in DOCA-salt rats. These data indicate that ET-1 participates, via activation of ETA receptors, in altered leukocyte-endothelial cell interactions in DOCA-salt rats, possibly by modulating expression of CAMs, and that the inflammatory status is associated with cardiac damage in mineralocorticoid hypertension.

Relative contribution of estrogen withdrawal and gonadotropins increase secondary to ovariectomy on prostaglandin generation in mesenteric microvessels.

Recent studies have established that ovariectomy impairs endothelial function, partially by increasing vasoconstrictor prostaglandins generation. Because ovariectomy causes concomitant lack of estrogen and increase of gonadotropins (ie, LH and FSH), in this study we explored the relative role of estrogen and LH/FSH in modulating vasoconstrictor prostaglandins generation in mesenteric arteriolar bed of SHR. Endothelium-dependent relaxation to acetylcholine (ACh) and bradykinin (Bk) was markedly reduced in ovariectomized (OVX) compared with SHR in physiological estrus (OE). Estrogen replacement (OVX + E), but not the decrease in LH/FSH levels with leuprolide (OVX + Leu), corrected the altered vasorelaxation response in OVX. Treatment of mesenteries with diclofenac, prostaglandin-H synthase (PGHS) inhibitor, significantly enhanced the relaxing response in arteries from OVX and OVX + Leu, but not those from OE, indicating that a PGHS-derived vasoconstrictor has modified the endothelium-dependent response during estrogen but not LH/FSH deprivation. Confirming these data, in response to exogenous arachidonic acid, whereas arteries from OVX and OVX + Leu exhibited a marked and similar vasoconstrictor response, the arteries from OE and OVX + E rats exhibited a slight vasodilation. We also demonstrated by RT-PCR that ovariectomy significantly increased PGHS-2 but not PGHS-1 mRNA expression in comparison to OE. The PGHS-2 overexpression in OVX was corrected by estrogen replacement, but not by the reduction of LH/FSH levels. Altogether these data strongly support a role for hypoestrogenism rather than LH/FSH enhancement, associated with the removal of ovaries, in the increase of vasoconstrictor prostaglandins, possibly by a mechanism involving PGHS-2 overexpression.

Intrauterine undernutrition--renal and vascular origin of hypertension.

OBJECTIVE: A large number of clinical and experimental studies supports the hypothesis that intrauterine undernutrition is an important determinant of hypertension, coronary heart disease and non-insulin-dependent diabetes in the adult offspring. In this review, the renal and vascular repercussions of maternal undernutrition are emphasized, and the physiopatologic mechanisms discussed. The origin of hypertension is detailed based upon the findings of kidney functional parameters and endothelium function studies. A working model linking hypertension to intrauterine undernutrition is proposed.

Intrauterine undernutrition: expression and activity of the endothelial nitric oxide synthase in male and female adult offspring.

OBJECTIVE: Epidemiological studies suggest that intrauterine undernutrition plays an important role in the development of arterial hypertension in adulthood. In an attempt to define the mechanisms whereby blood pressure may be raised, we have hypothesized that arteries from offspring of nutritionally restricted dams exhibit abnormalities in the endothelial function and in nitric oxide synthesis. In order to investigate the existence of potential gender differences on the effects of intrauterine undernutrition, both male and female offspring of pregnant Wistar rats on normal and restricted diets were studied in adulthood. METHODS: Female pregnant Wistar rats were fed either normal or 50% of the normal intake diets, during the whole gestational period. At 14 weeks of age, the rats were used for the study of vascular reactivity, eNOS and iNOS gene expression, eNOS activity and, in the case of females, estrogen levels. RESULTS: Intrauterine undernutrition induced hypertension in both male and female offspring, but hypertension was more severe in male rats. Endothelium-intact aortic rings from male and female rats in the restricted diet group exhibited increased responses to norepinephrine, decreased vasodilation to acetylcholine and unaltered responses to sodium nitroprusside in comparison to aortic rings from control rats. No gender-related differences were observed in the vascular reactivity studies. Intrauterine undernutrition promoted decreased gene expression for eNOS in aorta isolated from male, but not female, offspring, reduction in eNOS activity in both male and female offspring and impairment in synthesis of estrogen in female offspring. CONCLUSION: Our data show that intrauterine undernutrition: (1) induces hypertension both in the male and female offspring, hypertension being more severe in male than in female rats; (2) alters endothelium-dependent responses in aortas from the resulting offspring. The endothelial dysfunction is associated with a decrease in activity/expression of eNOS in aortas from male offspring. The mechanism involved in altered response to ACh in female offspring might be a consequence of reduction in estrogen levels leading to reduced eNOS activity.

In vivo evidence for antioxidant potential of estrogen in microvessels of female spontaneously hypertensive rats.

In studies conducted in vitro, it has been demonstrated that estrogen has an antioxidant potential that may contribute to its protective effects on the cardiovascular system. However, the antioxidant effect of estrogen in vivo has not been demonstrated. To address this issue, in this study the effects of estrogen on oxidative stress were evaluated in microvessels studied in vivo. Oxidative stress was evaluated by using intravital microscopy in mesenteric arterioles from female spontaneously hypertensive rats (SHR) in physiological estrous (OE), ovariectomized (OVX), OVX treated with estradiol (E(2)), or estradiol + progesterone (E/P). The mesenteries were superfused with hydroethidine, a reduced and nonfluorescent precursor of ethidium bromide (EB). In the presence of reactive oxygen species, hydroethidine is transformed intracellularly in EB, which binds to DNA and can be detected by its red fluorescence. The percentage of EB-positive nuclei along the arteriolar wall in OVX (28.4 +/- 4.3) was significantly increased compared with OE (14.2 +/- 3.9; P<0.05). The OVX overproduction of oxyradicals was attenuated by E(2) (15.7 +/- 2.2) and E/P (14.8 +/- 0.8). Treatment with the superoxide dismutase mimetic MnTMPyP attenuated by 75% the oxidation of hydroethidine in both OE and OVX. Conversely, mannitol, that decomposes hydroxyl radical, and L-NAME, a nitric oxide synthase inhibitor, had no significant effects on hydroethidine oxidation. No differences on hydrogen peroxide plasma concentration were observed among the groups, suggesting that superoxide anion is the most likely oxyradical involved in the increased oxidative stress observed in OVX. The treatment of mesenteries with diphenyleneiodonium (DPI), an nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase inhibitor, but not with oxypurinol, a xanthine-oxidase inhibitor, produced a significant reduction of oxyradical generation in OVX microvessels and a slight decrease in those from OE. Chronic treatment of female SHR with losartan caused similar decreases in oxyradicals in both OE and OVX, whereas diclofenac and verapamil had no effects. Together these data suggest that estrogen reduces superoxide anion bioavailability in vivo. The antioxidant effect of estrogen, which can contribute to a less pronounced endothelial dysfunction in female SHR, may be dependent on a direct modulatory action of estrogen on NADPH activity.

Hipertensäo arterial: o endotélio e suas múltiplas funçöes / Arterial hypertension: endothelium and multiples functions

O endotélio sadio exerce funçöes anticoagulante, vasodilatadora e antiinflamatória que säo essenciais para a manutençäo da homeostasia. Em várias doenças cardiovasculares, entre elas a hipertensäo arterial, ocorre disfunçäo endotelial. O endotélio normal tem funçäo protetora contra o desenvolvimento de lesöes vasculares mantendo a vasodilataçäo, inibindo a agregaçäo plaquetária, a adesäo leucocitária e a proliferaçäo das células musculares lisas. Essas açöes säo exercidas principalmente pelo óxido nítrico, considerado o mais importante fator endotelial, ou EDRF (do inglês Endothelial-Derived Relaxing Factor), ao lado da prostaciclina e do fator hiperpolarizante derivado do endotélio. O endotélio pode também gerar fatores contráteis conhecidos por EDCFs, como as endotelinas, a angiotensina II, as prostaglandinas vasoconstritoras e espécies reativas de oxigênio. A disfunçäo endotelial na hipertensäo leva a desequilíbrio da produçäo/liberaçäo dos fatores contráteis e relaxantes e: 1) provoca diminuiçäo da geraçäo de óxido nítrico/aumento das espécies reativas de oxigênio, aumentando dessa forma o tônus vascular; 2) contribui para o aumento da permeabilidade vascular levando à formaçäo de edema subendotelial; 3) aumenta a expressäo de moléculas de adesäo com conseqüente aumento da aderência leucocitária à parede vascular; 4) acelera a coagulaçäo intravascular; 5) aumenta a proliferaçäo de células musculares lisas, levando à hipertrofia/hiperplasia da parede vascular. Torna-se evidente assim que o endotélio tem papel central na hipertensäo, controlando a permeabilidade vascular, a adesäo leucocitária, a proliferaçäo de células musculares lisas, a coagulaçäo e o equilíbrio entre fatores endoteliais (os EDRFs e os EDCFs).

The effect of chronic nitric oxide inhibition on vascular reactivity and blood pressure in pregnant rats

CONTEXT: The exact mechanism involved in changes in blood pressure and peripheral vascular resistance during pregnancy is unknown. OBJECTIVE:To evaluate the importance of endothelium-derivated relaxing factor (EDRF) and its main component, nitric oxide, in blood pressure and vascular reactivity in pregnant rats. DESIGN: Clinical trial in experimentation animals. SETTING: University laboratory of Pharmacology. SAMPLE: Female Wistar rats with normal blood pressure, weight (152 to 227 grams) and age (90 to 116 days). INTERVENTION: The rats were divided in to four groups: pregnant rats treated with L-NAME (13 rats); pregnant control rats (8 rats); virgin rats treated with L-NAME (10 rats); virgin control rats (12 rats). The vascular preparations and caudal blood pressure were obtained at the end of pregnancy, or after the administration of L-NAME in virgin rats. MAIN MEASUREMENTS: The caudal blood pressure and the vascular response to acetylcholine in pre-contracted aortic rings, both with and without endothelium, and the effect of nitric oxide inhibition, Nw-L-nitro-arginine methyl-ester (L-NAME), in pregnant and virgin rats. The L-NAME was administered in the drinking water over a 10-day period. RESULTS: The blood pressure decreased in pregnancy. Aortic rings of pregnant rats were more sensitive to acetylcholine than those of virgin rats. After L-NAME treatment, the blood pressure increased and relaxation was blocked in both groups. The fetal-placental unit weight of the L-NAME group was lower than that of the control group. CONCLUSION: Acetylcholine-induced vasorelaxation sensitivity was greater in pregnant rats and that blood pressure increased after L-NAME administration while the acetylcholine-induced vasorelaxation response was blocked.