Farmacoterapia e análise de mediadores gasosos em pacientes hipertensos

OBJETIVO Evaluar el efecto del uso de antihipertensivos pertenecientes a las clases medicamentosas antagonistas de canales de calcio e inhibidores de la enzima convertidora de angiotensina en las concentraciones plasmáticas de ácido sulfhídrico y óxido nítrico en portadores de hipertensión arterial sistémica. MÉTODO Estudio transversal con abordaje cuantitativo realizado con hipertensos que toman antihipertensivos de las clases de inhibidores de la enzima convertidora de angiotensina o antagonistas de los canales de calcio. RESULTADOS Se verificó que la concentración de óxido nítrico plasmático fue significativamente mayor en hipertensos que estaban usando inhibidores de la enzima convertidora de angiotensina (pOBJECTIVE To evaluate the effect of using antihypertensive classes of drugs of the calcium channel antagonists and inhibitors of angiotensin-converting enzyme in plasma concentrations of hydrogen sulfide and nitric oxide in patients with hypertension. METHODS Cross-sectional study with quantitative approach conducted with hypertensive patients in use of antihypertensive classes of drugs: angiotensin-converting enzyme inhibitors or calcium channel antagonists. RESULTS It was found that the concentration of plasma nitric oxide was significantly higher in hypertensive patients that were in use of angiotensin-converting enzyme inhibitors (pOBJETIVO Avaliar o efeito do uso de anti-hipertensivos pertencentes às classes medicamentosas antagonistas de canais de cálcio e inibidores da enzima conversora de angiotensina nas concentrações plasmáticas de ácido sulfídrico e óxido nítrico em portadores de hipertensão arterial sistêmica. MÉTODO Estudo transversal com abordagem quantitativa realizado com hipertensos em uso de anti-hipertensivos das classes inibidores da enzima conversora de angiotensina ou antagonistas dos canais de cálcio. RESULTADOS Verificou-se que a concentração de óxido nítrico plasmático foi significativamente maior em hipertensos que estavam em uso de inibidores da enzima conversora de angiotensina (

Estudo da termorregulação como marcador de agravamento do quadro de sepse experimental em modelo animal

Objective: to analyze variations in body temperature and in plasma nitrate and lactate concentrations in rats submitted to the experimental sepsis model. Method: a total of 40 rats divided equally into five groups. The induction of endotoxemia was performed with intravenous administration of lipopolysaccharide, 0.5 mg/Kg, 1.5 mg/Kg, 3.0 mg/Kg, and 10 mg/Kg, respectively. The control group received 0.5 mL of saline solution. The experiment lasted six hours, with evaluations performed at 0 (baseline data), 2nd, 4th, and 6thhours. Results: The animals that received doses up to 3.0 mg/kg showed a significant increase in body temperature compared to the group with 10 mg/kg, which showed a decrease in these values. The increase in plasma nitrate and lactate concentrations in the groups with lipopolysaccharide was significantly higher than in the group that received the saline solution and was correlated with the increase in body temperature. Conclusion: the variations in body temperature observed in this study showed the dose-dependent effect of lipopolysaccharide and were correlated with the increase in the concentrations of nitrate and plasma lactate biomarkers. The implications of this study are the importance of monitoring body temperature, together with the assessment of these pathophysiological markers, which suggest worsening in the prognosis of sepsis.Objetivo: analisar as variações na temperatura corporal e nas concentrações de nitrato e lactato plasmáticos em ratos submetidos ao modelo de sepse experimental. Método: foram utilizados 40 ratos divididos igualmente em cinco grupos. A indução da endotoxemia foi realizada com administração endovenosa de lipopolissacarídeo, respectivamente 0,5 mg/Kg, 1,5 mg/Kg, 3,0 mg/Kg e 10 mg/Kg. O grupo controle recebeu 0,5 mL de solução salina. O experimento teve duração de seis horas, com avaliações realizadas na 0 (dados basais), 2a, 4a e 6a hora. Resultados: os animais que receberam doses de até 3,0 mg/Kg apresentaram aumento significativo na temperatura corporal em relação ao grupo com 10 mg/Kg, que apresentou diminuição nesses valores. O aumento nas concentrações de nitrato e lactato plasmáticos nos grupos com lipopolissacarídeo foi significativamente superior ao grupo que recebeu salina e esteve correlacionado com o aumento na temperatura corporal. Conclusão: as variações na temperatura corporal observadas neste estudo mostraram efeito dose dependentes de lipopolissacarídeo e estiveram correlacionadas com o aumento nas concentrações dos biomarcadores nitrato e lactato plasmáticos. O estudo traz como implicações, a importância no monitoramento da temperatura corporal, em conjunto com a avaliação destes marcadores fisiopatológicos, os quais sugerem agravamento no prognóstico da sepse.Objetivo: analizar las variaciones de la temperatura corporal y de las concentraciones de nitrato y lactato en plasma en ratones sometidos a un modelo de sepsis experimental. Método: se utilizaron 40 ratones divididos en cinco grupos iguales. La inducción de la endotoxemia se realizó mediante administración intravenosa de 0,5 mg/Kg, 1,5 mg/Kg, 3,0 mg/Kg y 10 mg/Kg de lipopolisacárido, respectivamente. El grupo de control recibió 0,5 mL de solución salina. El experimento duró seis horas, con evaluaciones realizadas a la hora 0 (datos de referencia) y a la 2a, 4a y 6ahora. Resultados: los animales que recibieron dosis de hasta 3,0 mg/kg presentaron un aumento significativo de la temperatura corporal, en comparación con el grupo al que se le administró 10 mg/kg, que presentó una disminución de dichos valores. En los grupos a los que se les administró lipopolisacárido, el aumento en las concentraciones de nitrato y lactato en plasma fue significativamente mayor que en el grupo al que se le administró la solución salina y estuvo correlacionado con el aumento de la temperatura corporal. Conclusión: las variaciones de la temperatura corporal observadas en este estudio mostraron que los efectos dependieron de la dosis de lipopolisacárido, y estuvieron correlacionadas con el aumento en la concentración de biomarcadores, como el nitrato y lactato en plasma. El estudio reveló la importancia del control de la temperatura corporal, junto con la evaluación de estos marcadores fisiopatológicos, que sugieren un empeoramiento en el pronóstico de la sepsis

Estresse oxidativo não está associado à disfunção vascular em um modelo de diabetes induzida por aloxana em ratos

OBJECTIVES: To verify if an experimental model of alloxan-diabetic rats promotes oxidative stress, reduces nitric oxide bioavailability and causes vascular dysfunction, and to evaluate the effect of N-acetylcysteine (NAC) on these parameters. METHODS: Alloxan-diabetic rats were treated or not with NAC for four weeks. Plasmatic levels of malondialdehyde (MDA) and nitrite/nitrate (NOx), the endothelial and inducible nitric oxide synthase (eNOS and iNOS) immunostaining and the vascular reactivity of aorta were compared among diabetic (D), treated diabetic (TD) and control (C) rats. RESULTS: MDA levels increased in D and TD. NOx levels did not differ among groups. Endothelial eNOS immunostaining reduced and adventitial iNOS increased in D and TD. The responsiveness of rings to acetylcholine, sodium nitroprusside, and phenylephrine did not differ among groups. CONCLUSIONS: NAC had no effect on the evaluated parameters and this experimental model did not promote vascular dysfunction despite the development of oxidative stress.OBJETIVOS: Verificar se um modelo experimental de diabetes por aloxana promove estresse oxidativo, reduz a disponibilidade de óxido nítrico e causa disfunção vascular, e avaliar o efeito da N-acetilcisteína (NAC) nesses parâmetros. MÉTODOS: Ratos diabéticos por aloxana foram tratados com NAC por quatro semanas. Níveis plasmáticos de malondialdeído (MDA) e nitrito/nitrato (NOx), imunomarcação para óxido nítrico sintase endotelial e induzida (eNOS e iNOS) e reatividade vascular da aorta foram comparados entre ratos diabéticos (D), diabéticos tratados (TD) e controles (C). RESULTADOS: O MDA aumentou nos grupos D e TD. O NOx não diferiu entre os grupos. A marcação da eNOS no endotélio reduziu e a da iNOS na adventícia aumentou nos grupos D e TD. A responsividade dos anéis vasculares à acetilcolina, nitroprussiato de sódio e fenilefrina não diferiu entre os grupos. CONCLUSÕES: A NAC não teve efeito sobre os parâmetros avaliados. Esse modelo experimental não promoveu disfunção vascular apesar do desenvolvimento de estresse oxidativo

Correlation between body temperature, blood pressure and plasmatic nitric oxide in septic patients

OBJECTIVE: to investigate whether there is a relationship between plasmatic levels of nitrate, body temperature, and blood pressure values in patients with sepsis, severe sepsis and septic shock. METHOD: prospective observational study performed in a Brazilian hospital; data were collected from July to December 2009. Thirty blood samples were obtained from a total of 29 patients. Blood samples (10ml) were collected for subsequent laboratory analysis to determine nitrate levels in the plasma. RESULTS: nitric oxide synthesis is increased in patients with septic shock, and is inversely correlated to the body temperature values. CONCLUSION: these data show that the measurement of body temperature and the observation of hypothermic conditions in septic patients could be important to guide the nursing regarding the evolution of individuals with sepsis to septic shock

Central Administration of Angiotensin-(1-7) Improves Vasopressin Impairment and Hypotensive Response in Experimental Endotoxemia

Angiotensin-(1-7) [Ang-(1-7)]/Mas receptor is a counter-regulatory axis that counteracts detrimental renin-angiotensin system (RAS) effects, especially regarding systemic inflammation, vasopressin (AVP) release, and hypothalamic-pituitary-adrenal (HPA) activation. However, it is not completely understood whether this system may control centrally or systemically the late phase of systemic inflammation. Thus, the aim of this study was to determine whether intracerebroventricular (i.c.v.) administration of Ang-(1-7) can modulate systemic inflammation through the activation of humoral pathways in late phase of endotoxemia. Endotoxemia was induced by systemic injection of lipopolysaccharide (LPS) (1.5 mg/kg, i.v.) in Wistar rats. Ang-(1-7) (0.3 nmol in 2 µL) promoted the release of AVP and attenuated interleukin-6 (IL-6) and nitric oxide (NO) levels but increased interleukin-10 (IL-10) in the serum of the endotoxemic rats. The central administration of Mas receptor antagonist A779 (3 nmol in 2 µL, i.c.v.) abolished these anti-inflammatory effects in endotoxemic rats. Furthermore, Ang-(1-7) applied centrally restored mean arterial blood pressure (MABP) without affecting heart rate (HR) and prevented vascular hyporesponsiveness to norepinephrine (NE) and AVP in animals that received LPS. Together, our results indicate that Ang-(1-7) applied centrally promotes a systemic anti-inflammatory effect through the central Mas receptor and activation of the humoral pathway mediated by AVP

Ethanol consumption increases the expression of endothelial nitric oxide synthase, inducible nitric oxide synthase and metalloproteinases in the rat kidney

Objectives The effects of longterm ethanol consumption on the levels of nitric oxide (NO) and the expression of endothelial NO synthase (eNOS), inducible NO synthase (iNOS) and metalloproteinase-2 (MMP-2) were studied in rat kidney. Methods Male Wistar rats were treated with 20% ethanol (v/v) for 6 weeks. Nitrite and nitrate generation was measured by chemiluminescence. Protein and mRNA levels of eNOS and iNOS were assessed by immunohistochemistry and quantitative real-time polymerase chain reaction, respectively. MMP-2 activity was determined by gelatin zymography. Histopathological changes in kidneys and indices of renal function (creatinine and urea) and tissue injury (mitochondrial respiration) were also investigated. Results Chronic ethanol consumption did not alter malondialdehyde levels in the kidney. Ethanol consumption induced a significant increase in renal nitrite and nitrate levels. Treatment with ethanol increased mRNA expression of both eNOS and iNOS. Immunohistochemical assays showed increased immunostaining for eNOS and iNOS after treatment with ethanol. Kidneys from ethanol-treated rats showed increased activity of MMP-2. Histopathological investigation of kidneys from ethanol-treated animals revealed tubular necrosis. Indices of renal function and tissue injury were not altered in ethanol-treated rats. Conclusions Ethanol consumption increased renal metalloproteinase expression/activity, which was accompanied by histopathological changes in the kidney and elevated NO generation. Since iNOS-derived NO and MMPs contribute to progressive renal injury, the increased levels of NO and MMPs observed in ethanol-treated rats might contribute to progressive renal damage.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo, Brazil [06/60076-7]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (Brazil

Ethanol Consumption Alters the Expression and Reactivity of Adrenomedullin in the Rat Mesenteric Arterial Bed

Aims: Adrenomedullin (AM) is a peptide that displays cardiovascular protective activity. We investigated the effects of chronic ethanol consumption on arterial blood pressure, vascular reactivity to AM and the expression of AM system components in the rat mesenteric arterial bed (MAB). Methods: Male Wistar rats were treated with ethanol (20% vol/vol) for 6 weeks. Systolic, diastolic and mean arterial blood pressure were monitored in conscious rats. Vascular reactivity experiments were performed on isolated rat MAB. Matrix metalloproteinase-2 (MMP-2) levels were determined by gelatin zymography. Nitrite and nitrate generation were measured by chemiluminescence. Protein and mRNA levels of pre-pro-AM, CRLR (calcitonin receptor-like receptor) and RAMP1, 2 and 3 (receptor activity-modifying proteins) were assessed by western blot and quantitative real-time polymerase chain reaction, respectively. Results: Ethanol consumption induced hypertension and decreased the relaxation induced by AM and acetylcholine in endothelium-intact rat MAB. Phenylephrine-induced contraction was increased in endothelium-intact MAB from ethanol-treated rats. Ethanol consumption did not alter basal levels of nitrate and nitrite, nor did it affect the expression of MMP-2 or the net MMP activity in the rat MAB. Ethanol consumption increased mRNA levels of pre-pro-AM and protein levels of AM in the rat MAB. Finally, no differences in protein levels or mRNA of CRLR and RAMP1, 2 and 3 were observed after treatment with ethanol. Conclusion: Our study demonstrates that ethanol consumption increases blood pressure and the expression of AM in the vasculature and reduces the relaxation induced by this peptide in the rat MAB.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo-FAPESP [06/60076-7, 10/09962-1

Systematization of the offering of a diet for inducing obesity in adult rats

Aim: To systematize the offering of foods which were highly palatable and rich in calories and to investigate the effects on morphometric and metabolic parameters of adult Wistar rats. Methods: The study used 15 male Wistar rats, aged 45 days old, divided into a control group and a cafeteria diet group. To the control group was offered a commercial diet ad libitum, while to the cafeteria diet group was offered the commercial diet supplemented each day with four items selected from a list of 28 foods. The consumption of foods from the cafeteria diet was checked daily, and the two groups’ consumption of water and feed was checked weekly. After seven weeks, the morphometric parameters were checked and animals were sacrificed for collection of blood and the deposit of perigonadal fat. Results: The mean weight of the cafeteria diet group was higher than that of the control group, as was abdominal circumference, deposit of perigonadal fat, body mass index and the Lee index. Furthermore, animals from the cafeteria diet group presented high blood levels of triglycerides; also, changes were not observed in levels of cholesterol and glucose. Animals from the cafeteria diet group ingested more calories, carbohydrates and fats than animals in the control group. Conclusion: This study showed that a protocol of offering a cafeteria diet formulated based in foods typically consumed by the Brazilian population can be used for inducing obesity in rats, requiring a relatively short time period for obtaining results. RESUMO Sistematização do oferecimento de uma dieta para indução de obesidade em ratos adultosObjetivo: sistematizar um protocolo de dieta de cafeteria para indução de obesidade em roedores a partir da ingestão de alimentos altamente palatáveis, ricos em gorduras e carboidratos. Método: foram utilizados ratos Wistar com 45 dias de vida, divididos aleatoriamente em grupo controle (GC) e grupo dieta de cafeteria (GDC). Ao GC foi oferecido dieta comercial balanceada para roedores à vontade e ao GDC foi oferecido a dieta comercial balanceada à vontade suplementada diariamente com quatro itens selecionados de uma lista de 28 alimentos. O consumo dos alimentos da dieta de cafeteria foi verificado diariamente e o consumo de água e ração dos dois grupos verificado semanalmente. Ao final das sete semanas foram verificados os parâmetros morfométricos, a seguir, os animais foram sacrificados para coleta de sangue e gordura perigonadal. Resultados: o peso médio do GDC foi significativamente maior do que do GC, assim como a circunferência abdominal e o depósito de gordura perigonadal. Adicionalmente, os animais do GDC apresentaram níveis sanguíneos significativamente elevados de triglicerídeos comparados aos animais do GC, entretanto, não foi observada alteração nos níveis de colesterol e glicose. Os animais do GDC ingeriram significativamente mais calorias, carboidratos e gorduras os animais do GC. Conclusão: este estudo mostrou que um protocolo de oferecimento de dieta de cafeteria formulado com base em alimentos tipicamente consumidos pela população brasileira, pode ser utilizado para indução de obesidade em roedores, necessitando de um período de tempo relativamente curto para obtenção de resultados