Perfil de riesgo cardiovascular en mujeres de tres entornos de la Provincia de Tucumán - Argentina / Cardiovascular risk profile in women from three different areas of the Province of Tucumán, Argentina

RESUMEN Introducción : El rol del entorno sobre la salud en la población femenina de Tucumán está poco estudiado. El objetivo del presente trabajo fue evaluar el perfil de riesgo cardiovascular de mujeres de los entornos rural, periurbano y urbano de la provincia de Tucumán (Argentina). Material y métodos : Se efectuó un estudio analítico transversal en 3 grupos de mujeres de Tucumán: rural (n=125), periurbano (n= 50) y urbano (n=112). Resultados : La presión arterial (PA) fue menor en el grupo rural; el grupo urbano presentó mayor frecuencia cardíaca y menor circunferencia de cuello. El 29,7% de las mujeres presentaron sobrepeso y el 42,4% obesidad, sin diferencia significativa entre los 3 grupos. La circunferencia de cuello estuvo aumentada en el 62% de las mujeres del grupo rural, 79% del periurbano y 41% del urbano (p<0,001). El grupo urbano presentó más frecuentemente tabaquismo. En los grupos urbano y periurbano fue mayor la proporción de mujeres con estudios superiores (p <0,001). El nivel educativo se correlacionó positivamente con la frecuencia cardíaca. Conclusiones : Independientemente del entorno las mujeres de Tucumán presentan sobrepeso u obesidad asociados a otros factores de riesgo para enfermedad cardiovascular. Ello debe ser tenido en cuenta para la elaboración de políticas y la toma de conductas a fin de mejorar su pronóstico.

ABSTRACT Background : The role of the environment on female population health in Tucumán has been little studied. This study aimed to evaluate the cardiovascular risk profile in women from rural, peri-urban and urban areas in the province of Tucumán (Argentina) and to analyse their differences. Methods : An analytical cross-sectional study was conducted in 3 groups of women from Tucumán: rural (n = 125), peri-urban (n = 50) and urban (n = 112). Results : Blood pressure (BP) was lower in the rural group; the urban group showed higher heart rate and smaller neck cir cumference. Of the studied women, 29.7% were overweight and 42.4% obese, and no significant differences were found in the 3 groups. Increased neck circumference was observed in 62% of women in the rural group, 79% in the peri-urban group and 41% in the urban group (p <0.001). Smoking was more frequent in the urban group. In the urban and peri-urban groups, the proportion of women with higher education level was greater (p <0.001). Education level was positively correlated with heart rate. Conclusion : Regardless of the environment, women from Tucumán are overweight or obese and have other risk factors for cardiovascular disease. This should be considered when planning policies and making decisions in order to improve their prognosis.

Evaluación de la función ventricular en la hipertensión pulmonar por resonancia magnética cardíaca / Evaluation of ventricular function in pulmonary hypertension by cardiac magnetic resonance

Resumen Objetivo: Evaluar la función del ventrículo derecho (VD) e izquierdo (VI) en la hipertensión pulmonar (HP) mediante resonancia magnética cardíaca (RMC). Material y métodos: En pacientes con (grupo HP; n = 9) y sin (grupo control; n = 9) HP se evaluó volumen telediastólico (VTD) y telesistólico (VTS) y fracción de eyección (FE) de ventrículo derecho (VD) e izquierdo (VI), área de aurícula derecha (AD) e izquierda y diámetro de arteria pulmonar (AP). Resultados: En HP, el VD presentó mayor VTD y VTS y menor FE (HP 52 ± 5% vs. control 64 ± 2%; p < 0,05). Solo en HP se observó movimiento anormal del tabique interventricular y realce tardío en los puntos de inserción del VD en VI. En HP aumentó el área de AD y el diámetro de AP. En VD, solo en HP, la FE se correlacionó negativamente con VTD (Pearson r: –0,8290; p < 0,01) y VTS (Pearson r: –0,7869; p < 0,05). Conclusiones: La evaluación de pacientes con HP mediante RMC demuestra alteraciones fisiológicas y anatómicas de las cavidades derechas con disminución de la FE del VD que también afecta la interrelación VD/VI. Se recalca la importancia de una evaluación temprana y secuencial del VD con RMC para valorar la mejor estrategia terapéutica para cada caso en particular.

Abstract Objective: To evaluate the function of the right ventricle (RV) and left ventricle (LV) in pulmonary hypertension (PH) through cardiac magnetic resonance imaging (CMR). Material and method: In patients with (PH group; n = 9) and without PH (control group; n = 9), end-diastolic volume (EDV) and end-systolic volume (ESV) and ejection fraction (EF) of right (RV) and left (LV) ventricle, area of the right (RA) and left (LA) atrium and diameter of the pulmonary artery (PA) were evaluated. Results: In PH, the RV increased EDV and ESV and decreased EF (PH: 52 ± 5% vs. control: 64 ± 2%; p < 0.05). Abnormal movement of the interventricular septum and late enhancement in the insertion points of the RV in the LV were only observed in HP. HP increased the area of RA and the diameter of PA. In LV, only in HP, EF was negatively correlated with EDV (Pearson r: –0.8290; p < 0.01) and ESV (Pearson r: –0.7869; p < 0.05). Conclusions: CMR evaluation of patients with PH demonstrates physiological and anatomical alterations of the right cavities with decreased EF in RV that also affects the RV/LV interrelationship. The importance of an early and sequential evaluation of the RV with CMR is emphasized to assess the best therapeutic strategy for each particular case.

A novel endothelium-independent effect of insulin on basal vascular tone in cafeteria diet-induced hypertensive rats.

Insulin vasorelaxant effect in metabolic syndrome has been shown on precontracted vessels. However, the insulin effects on basal vascular tone and its interrelationship with nitric oxide (NO) and K-channels are unknown. To test the effect of insulin on the basal vascular tone in isolated aortic rings from the cafeteria diet-induced hypertensive rats and to determine the role of NO and K-channels on this insulin effect. Male Wistar rats were randomized into two groups: one group fed with a cafeteria diet (CafR) and another fed with a standard chow diet (control rats: CR). Then, in isolated aortic rings, the insulin effect on the basal tone and the role of K-channels were evaluated. Also, the endothelial function, NO levels, and resting membrane potential were measured. CafR increased blood pressure (138 ± 6.2 mmHg; n = 9 vs. CR: 109 ± 1.4 mmHg; n = 9; p < 0.001) and vascular basal tone. Insulin 400 mU/ml reduced basal tone in aortic rings (-284 ± 47 mg; n = 9). This effect was unaffected by endothelium removal or NG-nitro-l-arginine methyl ester (L-NAME) treatment. Likewise, CafR showed low NO levels and a hyperpolarized resting membrane potential. Insulin decreased the resting membrane potential and the KCa and Kv channels blockers abolished this effect. In CafR, endothelial dysfunction is accompanied by an increased basal tone. Insulin reduced it by Kv and KCa channels dependent mechanisms, using an endothelium-independent pathway. These results highlight a novel insulin effect on basal tone of aortic rings from animals with metabolic syndrome and endothelial dysfunction, pathophysiological conditions associated with human hypertension.

Changes in vascular function and autonomic balance during the first trimester of pregnancy and its relationship with the new-born weight.

This study aimed to evaluate vascular function changes and autonomic balance during the first trimester of pregnancy and its relationship with the new-born weight. This prospective study performed in pregnant (PG) women and after delivery (not pregnant: NPG) evaluated the endothelial function (EF) and arterial stiffness (AS) by a non-invasive method. We evaluated the heart rate variability (HRV), parasympathetic nervous system (PNS), sympathetic nervous system (SNS) indexes by electrocardiogram (5 min) and the urinary nitrite excretion (NOx). PG increased EF and NOx and decreased AS and HRV. PG decreased the PNS index and augmented the SNS index. The new-born weight positively correlated with the PNS index (Pearson's r: 0.4291; p<.05), NOx, HRV and negatively correlated with AS. In summary, in pregnancy, although haemodynamically, the SNS activation plays a compensatory role, the low rates of PNS inhibition are essential to ensure normal foetal growth.Impact StatementWhat is already known on this subject? In pregnancy, there are adaptive physiological changes in the cardiovascular system that include increases of EF and decreases AS with an SNS activation. The study of HRV lets to predict the SNS and PNS balance and how they affect blood pressure and vascular function.What the results of this study add? Although it is known that SNS activation plays a compensatory role in healthy pregnancy, this study adds the critical role of PNS. Early in pregnancy, the low rates of PNS inhibition are essential to ensure normal foetal growth.What the implications are of these findings for clinical practice and/or further research? The present results show a potential predictive value of SNS and PNS activity early in pregnancy. It will provide valuable information not only on the pregnant woman's vascular function but also on the new-born weight.

Disparate Effect of Antioxidant Supplements on the Basal Tone and Vascular Remodeling of the Aorta in Hypertensive Rats.

BACKGROUND: Oxidative stress plays an essential role in the vascular tone in hypertension; however, the mechanisms remain unclear. AIM: This study aimed to determine the antioxidant effect of tempol and vitamin C (Vit-C) on the basal tone and vascular remodeling of the aorta in nitric oxide (NO) deficiency-induced hypertensive rats. METHOD: Male Sprague-Dawley rats were induced to hypertension by Nω-nitro-L-arginine methyl ester (L-NAME). Animals were randomized as follows: vehicle (Control: CR), CR-tempol, CR-Vit-C, L-NAME, L-NAME-tempol, and L-NAME-Vit-C. After 6 weeks of treatment, the basal aortic tone was evaluated by sodium nitroprusside (SNP) and calcium-free medium. Endothelial function, NO, reduced-to-oxidized glutathione (GSH/GSSG) ratio, resting membrane potential (mP), and vascular remodeling were also measured. RESULTS: L-NAME rats showed an increased basal tone that was blunted by both SNP (-547 ± 69; n = 7 vs. CR: -7.5 ± 6.7 mg; n = 7; p < 0.001) and calcium-free medium. Tempol or Vit-C did not reverse hypertension, and the high basal tone was decreased only with tempol. In L-NAME rats, only tempol partially improved endothelial function, GSH-to-GSSG ratio, mP values, and vascular remodeling. CONCLUSIONS: Tempol decreased calcium-dependent basal aortic tone and improved vascular homeostasis in L-NAME rats. Vit-C did not lead to a similar effect, suggesting that alterations in the superoxide dismutase pathway may play a role in the basal aortic tone.

Vascular Function in Children with Low Birthweight and Its Relationship with Early Markers of Cardiovascular Risk.

UNLABELLED: Low birthweight (LBW) increases the risk of developing cardiovascular diseases (CVD). Few studies have established its impact at early ages. AIMS: To study endothelial function (EF) and arterial stiffness (AS) and their relationship to early markers of CVD risk in children with LBW. METHODS: In children with LBW (4-6 years; n = 53), anthropometric, haemodynamic and laboratory parameters, including HOMA-IR, hs-CRP, adiponectin and leptin, were determined. EF and AS were evaluated by digital pulse plethysmography. Data were compared with a control group (n = 33). RESULTS: In both groups, anthropometric parameters remained within normal limits. Insulin and HOMA-IR had normal values, but they were significantly augmented in LBW children. LBW children showed higher leptin and hs-CRP levels than the control group. The LBW group had decreased EF (37.5 ± 5.6%) compared with the control group (75.0 ± 11.9%; p < 0.01), however without differences in AS. In LBW children, EF was negatively correlated with waist circumference, leptin, hs-CRP and with a cumulative score of risk factors. CONCLUSIONS: LBW children display altered EF that is related to early changes in CVD risk factors. The differences found in the metabolic parameters might indicate a pro-inflammatory state. This hypothesis is also supported by the laboratory findings and the correlation between EF and the number of CVD risk factors, suggesting that very early lifestyle interventions may be needed.

Gestión en salud y su articulación con el sector científico en la atención primaria de la salud / Health management and its articulation with the scientific sector in the primary health care

Objetivos: Determinar los programas y proyectos de investigación e intervención, incluyendo diagnósticos de salud, entre Abril de 2001 a Diciembre del 2007, en la Provincia de Tucumán, Argentina. Materiales y Métodos: Para los proyectos de investigación científica en salud se utilizó la base de datos del Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) y la Universidad Nacional de Tucumán (UNT). Para las investigaciones socio-sanitarias se realizaron entrevistas a actores claves involucrados en la gestión del conocimiento, funcionarios del gobierno del Ministerio de Salud y de la Secretaría de Ciencia y Técnica de Innovación Productiva de la Provincia, Ministerio de Desarrollo Social y a autoridades del Sistema Provincial de Salud. Resultados: Medicina representó el 4,9% del total de Proyectos financiados por la Universidad y el 1,9% del total de Programas aprobados por la Secretaría de Ciencia y Técnica de la UNT. Una situación similar se describe para nuestra provincia en relación a los subsidios otorgados por CONICET con el 2% del total de financiamiento. La Investigación Clínica y Epidemiológica fueron los temas más investigados de acuerdo a la clasificación presentada. De acuerdo con la encuesta, el 32% de los entrevistados opinó que “articula bastante” la investigación científica con los programas de la Atención Primaria de la Salud. Conclusiones: Hay escaso conocimiento sobre los proyectos de investigación en salud financiados por entidades públicas en las diferentes áreas geográficas estudiadas (Metropolitana, Agroindustrial y SILOS). Se observó que a nivel institucional universitario el área de Ciencias de la Salud y especialmente Medicina, es un área de vacancia.

Aim: To determine programs and projects of research and intervention, including diagnosis of health, during April 2001 to December 2007, in the Province of Tucuman, Argentina. Material and Methods: Data were obtained from public organisms of the Province of Tucuman. For research in health were used the data base of the National Scientific and Technical Research Council - Argentina (CONICET) and the National University of Tucuman (UNT). For research in Health and social care were realized interviews to key actors directly involved in knowledge management, Government officials of the Ministry of Health and the Secretary of Science and Technology of Productive Innovation of the Province of Tucuman, and Ministry of Social Development and the officials of the Health System of Tucuman. Results: Medicine accounted 4.9% of all projects funded by the University and 1.9% of total approved by the Ministry of Science and Technology of UNT. A similar situation is described for our province in relation to grants from CONICET with the 2% of total funding. Clinical and Epidemiological Research were the most investigated according to the classification presented. According to the survey, 32% of respondents felt that “articulates quite” the scientific research programs with Primary Health Care. Conclusions: There is little knowledge about health research projects funded by public entities in different geographical areas studied (Metropolitan, Agroindustrial and SILOS). It was noted that in a university institutional area, Health Sciences, and Medicine in particular, is an area of vacancy.

Tempol blunts afferent arteriolar remodeling in chronic nitric oxide-deficient hypertension without normalizing blood pressure.

BACKGROUND/AIM: Renal preglomerular vessels play a central role in modulating renal function and injury, especially during conditions of renal hemodynamic stress such as hypertension. We evaluated whether improving the balance between nitric oxide (NO) and oxidative stress improves the morphological alterations of renal afferent arterioles that occur in NO deficiency-induced hypertension. METHODS: We measured indices of NO and oxidative stress and evaluated renal morphology and afferent arteriolar remodeling in rats treated with vehicle, L-NAME or L-NAME plus tempol (a superoxide dismutase mimetic) for 6 weeks. RESULTS: L-NAME-treated rats had hypertension, lower urinary and renal NO indices, higher renal cortical levels of TBARS, GSSG and GSSG/GSH. This was associated with significant eutrophic inward remodeling of the afferent arterioles; they had a marked decrease in arteriolar lumen area and a striking increase in arteriolar wall thickness and media to lumen ratio. Tempol did not significantly reduce blood pressure, but increased NO levels, decreased oxidative stress and partially blunted L-NAME-induced remodeling of afferent arterioles. CONCLUSION: L-NAME-induced remodeling of afferent arterioles is blunted by tempol. This beneficial effect on remodeling is associated with increases in NO indices, decreases in oxidative stress, without significant decreases in blood pressure. Thus, the balance between these components may contribute to the altered renal hemodynamics and function in this model.

Arterial stiffness and endothelial function in obese children and adolescents and its relationship with cardiovascular risk factors.

BACKGROUND: Obesity is related to an increase in the rates of cardiovascular disease. OBJECTIVE: To establish the impact of obesity on vascular function (endothelial function and arterial stiffness) in children and adolescents and its relationship to cardiovascular risk factors. METHODS: In obese (OB) children and adolescents, endothelial function and arterial stiffness were evaluated by a pulse plethysmography method (reactive hyperemia and index of digital volume waveforms, respectively). Data were compared with the non-obese (non-OB) group (body mass index >10th to <97th percentile). Anthropometric parameters, body fat percentage, fasting glucose, lipid profile, insulinemia, HOMA-IR and hemodynamic parameters were determined in both groups. RESULTS: Body mass index, weight, waist circumference, body fat, insulinemia and HOMA-IR were significantly higher in the OB group. The OB group showed impaired endothelial function (15.8 ± 0.2%, n = 37) compared to the non-OB group (41.4 ± 5%, n = 20; p < 0.001) and increased arterial stiffness. Endothelial function was only negatively correlated with waist circumference and HOMA-IR in the OB group, whereas a positive correlation was found between insulinemia and HOMA-IR. CONCLUSIONS: This study shows that impaired vascular function is already present in OB children and adolescents. The fact that obesity is associated with some markers of cardiovascular risk suggests the importance of early lifestyle interventions in this population to prevent cardiovascular disease.

Antioxidant treatment reverts increased arterial Basal tone and oxidative stress in nephrectomized (5/6) hypertensive rats.

Nonischemic 5/6 nephrectomized rat (NefR) is a model of chronic kidney disease. However, little is known about vascular dysfunction and its relation with hypertension in NefR. Aims. To evaluate possible alterations of endothelial function, NO-bioavailability, and basal tone in aorta from NefR and the role of oxidative stress. Sprague Dawley rats were divided into sham rats (SR), NefR, and NefR treated with tempol (NefR-T). Mean arterial pressure (MAP) and renal function were determined. In isolated aortic rings the following was measured: 1-endothelial function, 2-basal tone, 3-NO levels, 4-membrane potential (MP), and 5-oxidative stress. NefR increased MAP (SR: 119 ± 4 mmHg; n = 7; NefR: 169 ± 6; n = 8; P < 0.001). Tempol did not modify MAP (NefR-T: 168 ± 10; n = 6; P < 0.001). NefR showed endothelial dysfunction, increased basal tone and decreased NO levels (SR: 32 ± 2 nA; n = 7, NefR: 10 ± 2; n = 8; P < 0.001). In both in vitro and in vivo tempol improves basal tone, NO levels, and MP. Oxidative stress in NefR was reverted in NefR-T. We described, for the first time, that aorta from NefR presented increased basal tone related to endothelial dysfunction and decreased NO-bioavailability. The fact that tempol improves NO-contents and basal tone, without decrease MAP, indicates that oxidative stress could be implicated early and independently to hypertension, in the vascular alterations.

Oxidative stress in hypertensive patients induces an increased contractility in vein grafts independent of endothelial function.

Objective. To evaluate the impact of oxidative stress on vascular reactivity to vasoconstrictors and on nitric oxide (NO) bioavailability in saphenous vein (SV) graft with endothelial dysfunction from hypertensive patients (HT). Methods. Endothelial function, vascular reactivity, oxidative state, nitrites and NO release were studied in isolated SV rings from HT and normotensive patients (NT). Only rings with endothelial dysfunction were used. Results. HT rings presented a hyperreactivity to vasoconstrictors that was reverted by diphenylene iodonium (DPI). In NT, no effect of DPI was obtained, but Nω-nitro-(L)-arginine methyl ester (L-NAME) increased the contractile response. NO was present in SV rings without endothelial function. Nitrites were higher in NT than in HT (1066.1 ± 86.3 pmol/mg; n = 11 versus 487.8 ± 51.6; n = 23; P < 0.01) and inhibited by nNOS inhibitor. L-arginine reversed this effect. Antioxidant agents increased nitrites and NO contents only in HT. The anti-nNOS-stained area by immunohistochemistry was higher in NT than HT. HT showed an elevation of oxidative state. Conclusions. Extraendothelial NO counter-regulates contractility in SV. However, this action could be altered in hypertensive situations by an increased oxidative stress or a decreased ability of nNOS to produce NO. Further studies should be performed to evaluate the implication of these results in graft patency rates.

Inflammatory and prothrombotic activation with conserved endothelial function in patients with chronic, asymptomatic Chagas disease.

UNLABELLED: Previously, our group showed a prothrombotic state in asymptomatic patients with chronic Chagas disease. The current paper studies the inflammatory status and endothelial function in these patients. METHODS: In 40 patients and 40 healthy volunteers, we evaluated prothrombotic state, blood parasitemia (molecular biology: polymerized chain reaction [PCR]-amplification), tissue factor pathway inhibitor antibodies (aTFPI), interleukin 6 (IL-6), and vascular cell adhesion molecule-1 (VCAM-1). Endothelial function was determined by reactive hyperemia (pulse plethysmography). RESULTS: In patients, prothrombin fragment 1 + 2, d-dimer, PAI-1, and fibrinogen were higher. Amplification of 121/122 primers (Trypanosoma cruzi) was positive in 45% of the patients. Patients presented higher values of aTFPI- immunoglobulin G (IgG; P < .05), aTFPI-IgM (P < .001), IL-6 (P = .004), and VCAM-1 (P = .00001). In both groups, endothelial function was preserved. CONCLUSIONS: We found that asymptomatic patients with chronic Chagas disease presented a prothrombotic/inflammatory status. The fact that endothelial function is still preserved suggests that prothrombosis and inflammation are primarily implicated in the beginning of cardiovascular damage.

Probables mecanismos involucrados en la etiopatogenia del estado protrombótico en la enfermedad de Chagas crónica. ¿Activación inflamatoria con función endotelial conservada? / Possible mechanisms involved in the pathogenesis of prothrombotic state Chronic Chagas disease. Inflammatory activation with preserved endothelial function?

Introducción: En el estadio indeterminado de la enfermedad de Chagas crónica, se comprobó un estado protrombótico asociado con factores de riesgo trombofílicos. La etiopatogenia de la enfermedad de Chagas es multifactorial sin que ninguno de los mecanismos involucrados explique por sí mismo el inicio y progresión de las lesiones. Objetivo: Evaluar probables mecanismos involucrados en la etiopatogenia del estado protrombótico en el estadio indeterminado de la enfermedad de Chagas crónica. Material y Métodos: Desde marzo de 2004 hasta diciembre de 2006 se evaluaron 40 pacientes chagásicos crónicos, 14 varones y 26 mujeres, (33.5 ± 4.9 años); en clase funcional I, de la clasificación clínica de la miocardiopatía chagásica crónica, comparándolos con un muestreo accidental de 40 voluntarios sanos, 19 varones y 21 mujeres (28.8 ± 6.3 años). Se evaluó la presencia del parásito por técnica de amplificación de las cadenas de polimerasa (PCR) y se determinó anticuerpo inhibidor de la vía extrínseca de la coagulación (aTFPI) por un método de ELISA optimizado, con valor de corte para aTFPI IgG >18 Uml-1 y para aTFPI IgM >15 Uml-1. Valores altos de aTFPI (IgG e IgM) se consideraron los >50 Uml-1. Se tomaron también muestras de sangre para la determinación por ELISA de dos marcadores de inflamación; Interleuquina 6 (IL-6) y de la molécula de adhesión a célula vascular (VCAM-1). La función endotelial se evaluó por pletismografía de onda de pulso digital para determinar hiperemia reactiva, la que discrimina sujetos con y sin disfunción endotelial. Resultados: En los pacientes chagásicos estudiados se detectó presencia del parásito por la técnica de amplificación de PCR utilizada en el 45 por ciento (n=18) de los casos. Los pacientes chagásicos presentaron valores de aTFPI mayores que los controles, con una p<0.05 para aTFPI IgG y p<0.001 para aTFPI IgM; superando en muy pocos casos los valores de corte establecidos para el método...

Reactivity of isolated toad aortic rings to angiotension II: the role of nitric oxide.

Little is known about the vascular actions of angiotensin II (Ang II) and nitric oxide (NO) in Amphibia. This study investigated (1) Ang II contractility, (2) NO concentrations, and (3) correlations between Ang II contractility, NO concentration and mean arterial pressure (MAP) in isolated Bufo arenarum toad aortic rings. Contractility was measured in isometric conditions, NO concentrations were determined by the Griess reaction, and MAP was determined by a direct method. In isolated toad aortic rings, Ang II produced a contractile response (292.7 +/- 89.2 mg; n = 20). Furthermore, a contractile response to norepinephrine (NE) was also obtained. A significant correlation between both the Ang II and NE contractile responses was found (r = 0.89; n = 11; P < 0.01). Administration of Ang II increased MAP values (Basal 16.8 +/- 1.7; n = 19 vs. Ang II 28.4 +/- 1.8 mmHg; n = 19; P < 0.001), and the increase of MAP by Ang II was positively correlated with the Ang II contractile response (P < 0.01). Administration of L-NAME also increased MAP values, and this effect was higher in those toads that presented a lower pressure response to Ang II (Pearson r = -0.68; P < 0.05). NO was present in all aortic rings, and its concentrations were negatively related to the Ang II contractile response (P < 0.036) and pressure response (Pearson r = -7.08; P < 0.001). These findings suggest that, in the B. arenarum toad, the NO system contra-regulates both the contractile and pressure Ang II responses, although its action could be different in each specimen.

Oxido nítrico en vasos usados para bypass: arteria mamaria vs. venas safena, rol de la tensión de estiramiento / Nitric oxide on bypass glasses: mammary artery vs safena vein, lift strain role

Una estimación de la función endotelial de arterias mamarias (art mam) y venas safenas (vena saf) usadas parabypass coronario sería medir la liberación de oxido nítrico (NO). En nuestro laboratorio observamos, en arterias de conejos, que el estiramiento (stretching) incrementa el NO. Objetivos: Determinar la presencia de endotelio en art mam y vena saf en pacientes (p) de bypass coronario y dosar el contenido de NO. Evaluar el rol del estiramiento. Métodos: Se usaron restos (1-4 anillos) de art mam y vena saf de 44 p del CMC con o sin factores de riesgo (FR) asociados. Se efectuaron dos protocolos in vitro: NT) anillos no tensados (precarga de 0g) y T) anillos tensados (precarga de 2g:art mam o 3g:vena saf). La presencia de endotelio se determinó por relajación (con endotelio) o no (sin endotelio) a acetilcolina 10-6M o bradiquinina 10-7M sobre precontractura con noradrenalina en baño de órgano aislado. El NO se dosó por método de Griess a los 15 min y en una curva de tiempo (90 min) con y sin tratamiento con L-Name 10-3M o Ang II (10-9 a -6M). Resultados: 7 p presentaron endotelio sin asociación con los FR. En T el NO basal fue mayor en vasos con endotelio en art mam (1829±259 vs 3699±65 pmol/mg n=19; p<0,05) y vena saf (694±103 vs 1290±216 pmol/mg, n=18; p<0,01). T estimuló laliberación de NO, este efecto es mayor en art mam con endotelio que en vena saf (p<0,001) y se mantiene aúnen anillos sin endotelio a los 90 min. En NT no hubo diferencias entre art mam y vena saf. Ang II mostródiferencias entre T y NT. L-Name solo inhibió el NO en vena saf con endotelio. Conclusiones: Los vasospresentaron disfunción endotelial generalizada sin asociación con ningún FR. Sin embargo, hubo liberación deNO incluso en anillos sin endotelio. Demostramos mayores niveles de NO en art mam. Sin embargo art mam yvena saf aumentan su liberación si se someten a T y este aumento se mantiene en la disfunción endotelial. Suorigen involucraría activación de la enzima NO Sintetasa neuronal(nNOS). La T activaría la nNOS, situaciónhomologable in vivo a la T que sufriere el vaso injertado en el circuito arterial coronario. Este mecanismocompensador de NO ayudaría a explicar la buena perfomance, aun en vena saf, de los puentes coronarios, más allá del FR asociado.

Oxido nítrico en vasos usados para bypass: arteria mamaria vs. venas safena, rol de la tensión de estiramiento / Nitric oxide on bypass glasses: mammary artery vs safena vein, lift strain role

Una estimación de la función endotelial de arterias mamarias (art mam) y venas safenas (vena saf) usadas parabypass coronario sería medir la liberación de oxido nítrico (NO). En nuestro laboratorio observamos, en arterias de conejos, que el estiramiento (stretching) incrementa el NO. Objetivos: Determinar la presencia de endotelio en art mam y vena saf en pacientes (p) de bypass coronario y dosar el contenido de NO. Evaluar el rol del estiramiento. Métodos: Se usaron restos (1-4 anillos) de art mam y vena saf de 44 p del CMC con o sin factores de riesgo (FR) asociados. Se efectuaron dos protocolos in vitro: NT) anillos no tensados (precarga de 0g) y T) anillos tensados (precarga de 2g:art mam o 3g:vena saf). La presencia de endotelio se determinó por relajación (con endotelio) o no (sin endotelio) a acetilcolina 10-6M o bradiquinina 10-7M sobre precontractura con noradrenalina en baño de órgano aislado. El NO se dosó por método de Griess a los 15 min y en una curva de tiempo (90 min) con y sin tratamiento con L-Name 10-3M o Ang II (10-9 a -6M). Resultados: 7 p presentaron endotelio sin asociación con los FR. En T el NO basal fue mayor en vasos con endotelio en art mam (1829±259 vs 3699±65 pmol/mg n=19; p<0,05) y vena saf (694±103 vs 1290±216 pmol/mg, n=18; p<0,01). T estimuló laliberación de NO, este efecto es mayor en art mam con endotelio que en vena saf (p<0,001) y se mantiene aúnen anillos sin endotelio a los 90 min. En NT no hubo diferencias entre art mam y vena saf. Ang II mostródiferencias entre T y NT. L-Name solo inhibió el NO en vena saf con endotelio. Conclusiones: Los vasospresentaron disfunción endotelial generalizada sin asociación con ningún FR. Sin embargo, hubo liberación deNO incluso en anillos sin endotelio. Demostramos mayores niveles de NO en art mam. Sin embargo art mam yvena saf aumentan su liberación si se someten a T y este aumento se mantiene en la disfunción endotelial. Suorigen involucraría activación de la enzima NO Sintetasa neuronal(nNOS). La T activaría la nNOS, situaciónhomologable in vivo a la T que sufriere el vaso injertado en el circuito arterial coronario. Este mecanismocompensador de NO ayudaría a explicar la buena perfomance, aun en vena saf, de los puentes coronarios, más allá del FR asociado. (AU)