Ruíz Gayo, Mariano

Dietary treatment with high-fat diets (HFD) triggeenrs diabetes and hyperleptinemia, con- comitantly with a partial state of leptin resistance that affects hepatic and adipose tissue but not the heart. In this context, characterized by widespread steatosis, cardiac lipid con- tent remains unchanged. As previously reported, HFD-evoked hyperleptinemia could be a pivotal element contributing to increase fatty-acid (FA) metabolism in the heart and to prevent cardiac steatosis. This metabolic adaptation might theoretically reduce energy efficiency in cardiomyocytes and lead to cardiac electrophysiological remodeling. There- fore the aim of the current study has been to investigate the impact of long-term HFD on cardiac metabolism and electrophysiological properties of the principal ionic currents responsible of the action potential duration in mouse cardiomyocytes. Male C57BL/6J mice were fed a control (10 kcal% from fat) or HFD (45 kcal% from fat) during 32 weeks. Quantification of enzymatic activities regulating mitochondrial uptake of pyruvate and FA showed an increase of both carnitine-palmitoyltransferase and citrate synthase activities together with a decrease of lactate dehydrogenase and pyruvate dehydrogenase activities. Increased expression of uncoupling protein-3, Mn-, and Cu/Zn-superoxide dismutases and catalase were also detected. Total glutathione/oxidized glutathione ratios were unaffected by HFD. These data suggest that HFD triggers adaptive mechanisms aimed at facilitating FA catabolism, and preventing oxidative stress. All these changes did not affect the dura- tion of action potentials in cardiomyocytes and only slightly modified electrocardiographic parameters.

Leptin causes vasodilatation both by endothelium-dependent and-independent mechanisms. Leptin is synthesized by perivascular adipose tissue (PVAT). The hypothesis of this study is that a decrease of leptin production in PVAT of spontaneously hypertensive rats (SHR) might contribute to adiminished paracrine anticontractile effect of the hormone. We have determined in aorta from Wistar-Kyoto (WKY) and SHR leptin mRNA and protein levels in PVAT, the effect of leptin and PVAT on contractile responses, and leptin-induced relaxation and nitricoxide (NO) production. Leptin mRNA and protein expression were significantly lower in PVAT from SHR. Concentration response curves to angiotensin II were significantly blunted in presence of PVAT as well as by exogenousleptin (10−9M) only in WKY. This anticontractile effect was endothelium-dependent. Vasodilatation induced by leptin was smaller in SHR than in WKY, and was also endothelium-dependent. More over, release of endothelial NO in response to acute leptin was higherin WKY compared to SHR, but completely abolished in the absence of endothelium. In conclusion, the reduced anticontractile effect of PVAT in SHR might be attributed to a reduced PVAT-derived leptin and to an abrogated effect of leptin on endothelial NO release probably due to an impaired activation of endothelial NO synthase

Background: The hypothesis of this study is that long-term high-fat diets (HFD) induce perivascular adipose tissue (PVAT) dysfunction characterized by a redox imbalance, which might contribute to aggravate endothelial dysfunction in obesity. Methods and Results: C57BL/6J mice were fed either control or HFD (45% kcal from fat) for 32 weeks. Body weight, lumbar and mesenteric adipose tissue weights were significantly higher in HFD animals compared to controls. The anticontractile effect of PVAT in mesenteric arteries (MA) was lost after 32 week HFD and mesenteric endothelial-dependent relaxation was significantly impaired in presence of PVAT in HFD mice (Emax = 71.065.1 vs Emax = 58.564.2, p,0.001). The inhibitory effect of L-NAME on Ach-induced relaxation was less intense in the HFD group compared with controls suggesting a reduction of endothelial NO availability. Expression of eNOS and NO bioavailability were reduced in MA and almost undetectable in mesenteric PVAT of the HFD group. Superoxide levels and NOX activity were higher in PVAT of HFD mice. Apocynin only reduced contractile responses to NA in HFD animals. Expression of ec-SOD and total SOD activity were significantly reduced in PVAT of HFD mice. No changes were observed in Mn-SOD, Cu/Zn-SOD or catalase. The ratio [GSSG]/([GSH]+[GSSG]) was 2- fold higher in the mesenteric PVAT from HFD animals compared to controls. Conclusions: We suggest that the imbalance between pro-oxidant (NOX, superoxide anions, hydrogen peroxide) and antioxidant (eNOS, NO, ecSOD, GSSG) mechanisms in PVAT after long-term HFD might contribute to the aggravation of endothelial dysfunction.

The aim of this study was to characterize alterations in vascular structure and mechanics in murine mesenteric arteries from obese non-hypertensive mice, as well as their relationship with adipokines. Four-week old C57BL/6J male mice were assigned either to a control (C, 10% kcal from fat) or a high-fat diet (HFD, 45% kcal from fat) for 32 weeks. HFD animals weighed 30% more than controls (p b 0.001), exhibited similar blood pressure, increased leptin, insulin and superoxide anion (O2 •−) levels, and reduced adiponectin levels and nitric oxide (NO) bioavailability. Arterial structure showed an outward remodeling with an increase in total number of both adventitial and smoothmuscle cells inHFD.Moreover, HFDmice exhibited an increased arterial stiffness assessed by β-values (C=2.4±0.5 vs HFD=5.3±0.8; p b 0.05) and aortic pulse wave velocity (PWV, C=3.4±0.1 vs HFD = 3.9 ± 0.1; p b 0.05). β-Values and PWV positively correlated with leptin, insulin or O2 •− levels, whereas they negatively correlated with adiponectin levels and NO bioavailability (p b 0.01). A reduction in fenestrae number together with an increase in type-I collagen amount (p b 0.05) were observed in HFD. These data demonstrate that HFD accounts for the development of vascular remodeling and arterial stiffness associated with adipokine dysregulation and oxidative stress, independently of hypertension development.

Vegetable oils such as palm oil (enriched in saturated fatty acids, SFA) and high-oleic-acid sunflower oil (HOSO, containing mainly monounsaturated fatty acids, MUFA) have emerged as the most common replacements for trans-fats in the food industry. The aim of this study is to analyze the impact of SFA and MUFA-enriched high-fat (HF) diets on endothelial function, vascular remodeling, and arterial stiffness compared to commercial HF diets. Five-week-old male C57BL6J mice were fed a standard (SD), a HF diet enriched with SFA (saturated oil-enriched Food, SOLF), a HF diet enriched with MUFA (unsaturated oil-enriched Food, UOLF), or a commercial HF diet for 8 weeks. Vascular function was analyzed in the thoracic aorta. Structural and mechanical parameters were assessed in mesenteric arteries by pressure myography. SOLF, UOLF, and HF diet reduced contractile responses to phenylephrine and induced endothelial dysfunction in the thoracic aorta. A significant increase in the -index, and thus in arterial stiffness, was also detected in mesenteric arteries from the three HF groups, due to enhanced deposition of collagen in the vascular wall. SOLF also induced hypotrophic inward remodeling. In conclusion, these data demonstrate a deleterious effect of HF feeding on obesity-related vascular alterations that is exacerbated by SFA.

Es curioso comprobar que en un mundo en el que más de 1000 millones de personas pasan hambre, uno de los mayores problemas de salud pública sea el de la obesidad. Se trata de una situación reciente, que empieza en la segunda mitad del siglo XX en algunas sociedades avanzadas, fundamentalmente en Estados Unidos y que, poco a poco, se ha ido extendiendo a otros paises, de América y de Europa principalmente, incluidos los de la Europa Mediterránea en los que el tipo de dieta habitual parecía prevenir este tipo de males. Algo similar empieza a ocurrir en los llamados países emergentes de América del Sur, México o China. 4 | Universidad CEU San Pablo La obesidad está, sin duda, ligada a un estilo de vida en el que el sedentarismo y el acceso a comidas abundantes con alto contenido calórico, sabrosas (alto contenido en sal, azucares fácilmente asimilables y grasas saturadas) y relativamente baratas, son la norma. Por el contrario, en las sociedades menos desarrolladas conseguir comida constituye muchas veces un objetivo inmediato, de forma que los individuos dedican gran parte del día a obtener alimentos.

A new synthetic methodology to provide cis-2-(1H-imidazol-4-yl)-cyclopropane carboxylic acids is described. These cyclopropanes are useful for the preparation of novel H3 receptor agents.

Most blood vessels are surrounded by adipose tissue. Similarly to the adventitia, perivascular adipose tissue (PVAT) was considered only as a passive structural support for the vasculature, and it was routinely removed for isolated blood vessel studies. In 1991, Soltis and Cassis demonstrated for the first time that PVAT reduced contractions to noradrenaline in rat aorta. Since then, an important number of adipocyte-derived factors with physiological and pathophysiological paracrine vasoactive effects have been identified. PVAT undergoes structural and functional changes in obesity. During early diet-induced obesity, an adaptative overproduction of vasodilator factors occurs in PVAT, probably aimed at protecting vascular function. However, in established obesity, PVAT loses its anticontractile properties by an increase of contractile, oxidative, and inflammatory factors, leading to endothelial dysfunction and vascular disease.The aim of this review is to focus on PVAT dysfunction mechanisms in obesity