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.

Vascular and autonomic function as early predictive biomarkers of the progression to gestational hypertension.

Background: The changes in endothelial function, arterial stiffness, and heart rate variability (HRV) produced in the first trimester of pregnancy in women who develop gestational hypertension (GH) are still being investigated. Objective: to evaluate the HVR, endothelial function, and arterial stiffness changes during the first trimester of pregnancy and their relationship with the development of GH. Methods: A group of women normotensive during the first trimester (n = 43), who later did (GH; n = 11) or did not (no-GH; n = 32) develop GH in that pregnancy, were enrolled. In the first trimester, endothelial function and arterial stiffness were evaluated through photoplethysmography. HRV, parasympathetic (PNS), and sympathetic (SNS) indexes were measured in a 5-minute continuous electrocardiogram record at rest sitting. The Griess reaction measured urinary nitrite excretion (NOx). Results: Systolic blood pressure (SBP) values were higher in GH (no-GH: 105.8 ± 2.0 vs. GH: 112.7 ± 3.0 mmHg; p < 0.05). Endothelial function was decreased, and arterial stiffness was increased in GH. Only in GH the arterial stiffness was correlated with SBP (Pearson's r: 0.5594; 95%CI: 0.06106-0.8681; p < 0.05). In HRV, GH decreased low-frequency power and the ratio SD2/SD1. The inhibition of PNS was lower in GH. The NOx was reduced in GH (no-GH: 3.4 ± 0.4 vs. GH: 0.3 ± 0.1 µM/L; p < 0.001). NOx was correlated negatively with the SNS index only in GH. Conclusions: Developed GH is preceded early in pregnancy by endothelial dysfunction and increased arterial stiffness. In this context, there are SNS-PNS interrelation modifications with less inhibition of PNS.

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.

Angiotensin-(1-7) inhibits sodium transport via Mas receptor by increasing nitric oxide production in thick ascending limb.

Sodium transport in the thick ascending loop of Henle (TAL) is tightly regulated by numerous factors, especially angiotensin II (Ang II), a key end-product of the renin-angiotensin system (RAS). However, an alternative end-product of the RAS, angiotensin-(1-7) [Ang-(1-7)], may counter some of the Ang II actions. Indeed, it causes vasodilation and promotes natriuresis through its effects in the proximal and distal tubule. However, its effects on the TAL are unknown. Because the TAL expresses the Mas receptor, an Ang-(1-7) ligand, which in turn may increase NO and inhibit Na+ transport, we hypothesized that Ang-(1-7) inhibits Na transport in the TAL, via a Mas receptor/NO-dependent mechanism. We tested this by measuring transport-dependent oxygen consumption (VO2 ) in TAL suspensions. Administering Ang-(1-7) decreased VO2 ; an effect prevented by dimethyl amiloride and furosemide, signifying that Ang-(1-7) inhibits transport-dependent VO2 in TAL. Ang-(1-7) also increased NO levels, known inhibitors of Na+ transport in the TAL. The effects of Ang-(1-7) on VO2 , as well as on NO levels, were ameliorated by the Mas receptor antagonist, D-Ala, in effect suggesting that Ang-(1-7) may inhibit transport-dependent VO2 in TAL via Mas receptor-dependent activation of the NO pathway. Indeed, blocking NO synthesis with L-NAME prevented the inhibitory actions of Ang-(1-7) on VO2 . Our data suggest that Ang-(1-7) may modulate TAL Na+ transport via Mas receptor-dependent increases in NO leading to the inhibition of transport activity.

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.

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.

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.

Nitric oxide modulates reactivity to angiotensin II in internal mammary arterial grafts in hypertensive patients without associated risk factors.

We investigated the effects of extraendothelial nitric oxide (NO) on angiotensin II (Ang II) reactivity in internal mammary artery (IMA) rings, as well as the impact of hypertension without associated risk factors in this response. Vascular reactivity, NO levels, and resting membrane potentials were determined in hypertensive (HT) and normotensive (NT) IMA rings. Only rings with endothelial dysfunction were included. Ang II produced a dose-dependent contraction that was higher in HT rings. Response to Ang II was potentiated by Nω-nitro L-arginine methyl ester (L-NAME) in NT but not in HT rings. The antioxidant agents tempol and diphenyleneiodonium (DPI) reverted the hyperreactivity to Ang II in HT rings. Extraendothelial NO was present in both NT and HT rings. However, NT rings showed higher values. L-NAME and S-methyl-L-thiocitrulline inhibited NO release in all cases. L-arginine reverted this inhibition. Both tempol and DPI increased NO release in both NT and HT rings. The number of vascular smooth muscle cells (VSMC) and anti-α-actin positive areas were lower in HT than in NT rings, without variations in wall thickness or wall/lumen ratio. With regard to resting membrane potential, we found in HT rings that the depolarization induced by Ang II was abolished by tempol. These findings suggest that extraendothelial NO counterregulates Ang II contractility in IMA rings; however, its action could be altered in hypertensive situations even though the patients did not have associated risk factors. We suggest two mechanisms: increased oxidative stress and a decreased ability of nNOS in VSMC to produce NO.

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.

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.

Internal mammary artery grafts reactivity in hypertensive patients: role of stretching in extraendothelial nitric oxide.

BACKGROUND: The internal mammary artery (IMA) used in bypass coronary surgery remains efficient for a longer time than other grafts, such as saphenous veins; however, its biological characteristics are incompletely defined. OBJECTIVE: To compare in IMA grafts from hypertensive (HT) and normotensive (NT) patients the presence of endothelium and their functionability, the response to passive stretching and basal tone, the reactivity to exogenous vasoconstrictors, the role of stretching in NO release, and the possible extraendothelial NO source. METHODS AND RESULTS: IMA rings contractility, presence of endothelium, and nitrite release were studied. An endothelial dysfunction associated with hypertension was found. IMA rings from HT had an impaired response to passive stretching, resulting in a decreased relaxation. All IMA grafts had an increased basal tone demonstrated by relaxation to SNP; however, a lesser response was found in HT. Interestingly, it was demonstrated that NO release was present in IMA grafts, despite an endothelial dysfunction and that stretching increased NO release. This effect was inhibited by Ca2+ -free media, L-NAME and a specific neuronal NO synthase (nNOS) inhibitor. Furthermore, the demonstration of the presence of nNOS in smooth muscle cells by immunohistochemistry supports a role of extraendothelial NO. CONCLUSION: We demonstrate the impact of hypertension in IMA grafts producing increased endothelial dysfunction, reduced response to passive stretching, increased basal tone, and impaired responsiveness to exogenous vasoconstrictors and NO release. A specific role of stretching in extraendothelial NO release was demonstrated, which may have an important role in the outcome of IMA grafts due to the protective actions of NO, even in the absence of the endothelium.

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)

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.

Structural changes in the renal vasculature in streptozotocin-induced diabetic rats without hypertension.

BACKGROUND/AIM: We evaluated in diabetic-streptozotocin rats (STZR) the structural changes of glomeruli, preglomerular vessels, glomerular tuft and renal parenchyma in order to determine the degree of renal injury and the presence of remodeling in afferent arterioles developed by diabetes without overimposed hypertension. METHODS: Renal mass index and histological score (glomerular number, density, tubular lesions and degree of arteriosclerosis) were estimated. In afferent arterioles the ratio of wall thickness/lumen was obtained by stereological methods. RESULTS: STZR developed diabetes without hypertension; renal mass index increased and matched changes in glomeruli (decrease of capillary number and enlargement of mesangium and basement capillary membrane). Both glomerular number and density as well as afferent arteriole number were diminished. Degenerative changes in both proximal (glycogenic and hyaline degeneration) and distal tubules (hyaline casts) were also observed. At variance with preglomerular vessels, the efferent arterioles only presented initial arteriosclerosis. Finally, the stereological study of afferent arterioles showed a significantly lower arteriolar lumen area and arteriolar wall thickness in STZR, resulting in a remodeling without modification of wall/lumen ratio. CONCLUSION: Diabetes, uncomplicated by hypertension, is associated with (1) a reduction in glomerular number; (2) degeneration in parenchyma and renal tubules, and (3) a specific pattern of remodeling in preglomerular vessels different from that induced by hypertension. Although this work demonstrated that these changes are not triggered by hypertension, further investigations are required in order to determine which mediators are involved in diabetic-vascular renal dysfunction.