Regulación de la liberación de renina durante la hipertensión renovascular

La hipertensión es un síndrome cardiovascular progresivo que surge de etiologías complejas e interrelacionadas. Los marcadores tempranos del síndrome a menudo están presentes antes de que la elevación de la presión sanguínea sea observada. El desarrollo de la hipertensión arterial se asocia con anomalías cardíacas y vasculares funcionales y estructurales que dañan el corazón, los riñones, el cerebro, los vasos, y otros órganos, y conducen a la morbilidad y muerte prematura. El sistema renina angiotensina y los riñones son los principales mecanismos que subyacen para el desarrollo de la hipertensión. La renina es la enzima limitante para la síntesis de la angiotensina II; la liberación de renina está regulada por mecanismos como el barorreceptor intrarrenal, la mácula densa (MD) y el sistema nervioso simpático. Desde la MD son liberadas prostaglandinas vasodilatadoras (PG) como PGI2 y PGE2, generadas por la ciclooxigenasa 2, que inducen la liberación de renina de las células yuxtaglomerulares. En esta revisión, mostramos los mecanismos interrelacionados entre la ciclooxigenasa 2 de la MD y la angiotensina II renal

Hypoglycaemic and Antioxidant Effects of Propolis of Chihuahua in a Model of Experimental Diabetes

Propolis is a bee-collected natural product that has been proven to have various bioactivities. This study tested the effects of a Mexican propolis on streptozotocin-induced diabetes mellitus in a murine model. The results showed that an ethanolic extract of propolis of Chihuahua (EEPCh) significantly inhibited increases in blood glucose and the loss of body weight in diabetic mice. EEPCh increased plasma insulin levels in STZ-diabetic mice, whereas, in untreated diabetic mice, there was no detection of insulin. EEPCh had a high antioxidant capacity (SA50 = 15.75 μg/mL), which was directly related to the concentrations of total phenols (314 mg GAE/g of extract) and flavonoids (6.25 mg QE/g of extract). In addition, increased activities of the enzymes superoxide dismutase, catalase, and glutathione peroxidase were observed in diabetic mice treated with EEPCh. Compounds such as pinocembrin, quercetin, naringin, naringenin, kaempferol, acacetin, luteolin, and chrysin were identified by HPLC-MS analysis. This investigation demonstrated that propolis of Chihuahua possesses hypoglycaemic and antioxidant activities and can alleviate symptoms of diabetes mellitus in mice. These effects may be directly related to the chemical composition of propolis, as most of the compounds identified in propolis are reportedly active in terms of the different parameters evaluated in this work

Regulación de la liberación de renina durante la hipertensión renovascular

Hypertension is a progressive cardiovascular syndrome arising from complex and interrelated etiologies. Early markers of the syndrome are often present before blood pressure elevation is observed. The development of arterial hypertension is associated with functional and structural cardiac and vascular abnormalities that damage the heart, kidneys, brain, vasculature, and other organs, and lead to morbidity and premature death. The kidney and the renin angiotensin system are the principal mechanisms that underlie for development of hypertension. Renin is the rate limiting enzyme for angiotensin II synthesis, and renin release is regulated by mechanisms as the intrarenal baroreceptor, the macula densa (MD) and the sympathetic nervous system. The MD releases vasodilator prostaglandins (PG) as PGI2 and PGE2, generated by cyclooxygenase 2, which induce renin release from juxtaglomerular cells. In this review, we show interrelated mechanisms between cyclooxygenase 2 of MD and renal angiotensin II.La hipertensión es un síndrome cardiovascular progresivo que surge de etiologías complejas e interrelacionadas. Los marcadores tempranos del síndrome a menudo están presentes antes de que la elevación de la presión sanguínea sea observada. El desarrollo de la hipertensión arterial se asocia con anomalías cardíacas y vasculares funcionales y estructurales que dañan el corazón, los riñones, el cerebro, los vasos, y otros órganos, y conducen a la morbilidad y muerte prematura. El sistema renina angiotensina y los riñones son los principales mecanismos que subyacen para el desarrollo de la hipertensión. La renina es la enzima limitante para la síntesis de la angiotensina II; la liberación de renina está regulada por mecanismos como el barorreceptor intrarrenal, la mácula densa (MD) y el sistema nervioso simpático. Desde la MD son liberadas prostaglandinas vasodilatadoras (PG) como PGI2 y PGE2, generadas por la ciclooxigenasa 2, que inducen la liberación de renina de las células yuxtaglomerulares. En esta revisión, mostramos los mecanismos interrelacionados entre la ciclooxigenasa 2 de la MD y la angiotensina II renal

Experimental Gestational Diabetes Mellitus Induces Blunted Vasoconstriction and Functional Changes in the Rat Aorta

Diabetic conditions increase vascular reactivity to angiotensin II in several studies but there are scarce reports on cardiovascular effects of hypercaloric diet (HD) induced gestational diabetes mellitus (GDM), so the objective of this work was to determine the effects of HD induced GDM on vascular responses. Angiotensin II as well as phenylephrine induced vascular contraction was tested in isolated aorta rings with and without endothelium from rats fed for 7 weeks (4 before and 3 weeks during pregnancy) with standard (SD) or hypercaloric (HD) diet. Also, protein expression of AT1R, AT2R, COX-1, COX-2, NOS-1, and NOS-3 and plasma glucose, insulin, and angiotensin II levels were measured. GDM impaired vasoconstrictor response (P<0.05 versus SD) in intact (e+) but not in endothelium-free (e−) vessels. Losartan reduced GDM but not SD e− vasoconstriction (P<0.01 versus SD). AT1R, AT2R, and COX-1 and COX-2 protein expression were significantly increased in GDM vessels (P<0.05 versus SD). Results suggest an increased participation of endothelium vasodilator mediators, probably prostaglandins, as well as of AT2 vasodilator receptors as a compensatory mechanism for vasoconstrictor changes generated by experimental GDM. Considering the short term of rat pregnancy findings can reflect early stage GDM adaptations

Effect of inter-renal aortic coarctation-induced hypertension on function and expression of vascular α1A- and α1D-adrenoceptors

We investigated the effect of inter-renal aortic coarctation on the function and expression of vascular a1A- and a1D-adrenoceptors and plasma angiotensin II (ATII) in rats. Male Wistar rats, either sham operated (SO), or with aortic coarctation for 7 (AC7) and 14 days (AC14) were used for agonist-induced pressor responses in vehicle (physiological saline)- and antagonist-treated anesthetized animals, immunoblot analysis (α1A- and α1D-adrenoceptor in aorta and caudal arteries), and immunoassay (plasma ATII). The a1D-adrenoceptor antagonist, BMY-7378 (BMY) blocked noradrenalineinduced responses in the order SO > AC7 ≫ AC14; in contrast, the α1A-adrenoceptor antagonist RS-100329 (RS), produced a marginal shift to the right of the dose-response curve to noradrenaline, along with a strong decrease of the maximum pressor effect in the order SO > AC7 = AC14. The potency of the α1A-adrenoceptor agonist A-61603 increased in rats with AC14, and responses were inhibited by RS in the order AC14 > AC7 > SO. In aorta, α1D-adrenoceptor protein increased in AC7 and decreased in AC14; α1A-adrenoreceptor protein increased in the caudal artery of AC7 and returned to control values in AC14. Plasma ATII increased in AC7 and AC14, compared with SO rats. These results suggest an early and direct relationship between ATII and a1D-adrenoreceptors in the development of hypertension in this experimental model