Matheus Monteiro

Adipokines, diabetes and atherosclerosis: an inflammatory association.

Cardiovascular diseases can be considered the most important cause of death in diabetic population and diabetes can in turn increase the risk of cardiovascular events. Inflammation process is currently recognized as responsible for the development and maintenance of diverse chronic diseases, including diabetes and atherosclerosis. Considering that adipose tissue is an important source of adipokines, which may present anti and proinflammatory effects, the aim of this review is to explore the role of the main adipokines in the pathophysiology of diabetes and atherosclerosis, highlighting the therapeutic options that could arise from the manipulation of these signaling pathways both in humans and in translational models.

Quercetin Improves Baroreflex Sensitivity in Spontaneously Hypertensive Rats

Quercetin is a well-known antioxidant. Here, we investigated the effects of treatment with quercetin on mean arterial pressure (MAP), heart rate (HR) and baroreflex sensitivity (BRS) in spontaneously hypertensive rats (SHR). SHR and their controls (WKY) were orally treated with quercetin (2, 10 or 25 mg/kg/day) or saline for seven days. On the 8th day, MAP and HR were recorded. BRS was tested using phenylephrine (8 mg/kg, i.v.) and sodium nitroprusside (25 mg/kg, i.v.). Oxidative stress was measured by tiobarbituric acid reactive species assay. The doses of 10 (n = 8) and 25 mg/kg (n = 8) were able to decrease the MAP in SHR (n = 9) (163 ± 4 and 156 ± 5 vs. 173 ± 6, respectively, p < 0.05) but not in WKY (117 ± 1 and 118 ± 2 vs. 113 ± 1, respectively, p < 0.05). The dose of 25 mg/kg/day increased the sensitivity of parasympathetic component of the baroreflex (−2.47 ± 0.31 vs. −1.25 ± 0.8 bpm/mmHg) and decreased serum oxidative stress in SHR (2.04 ± 0.17 vs. 3.22 ± 0.37 nmol/mL, n = 6). Our data suggest that treatment with quercetin reduces hypertension and improves BRS in SHR via reduction in oxidative stress.

Angiotensin-II-derived reactive oxygen species on baroreflex sensitivity during hypertension: new perspectives

Hypertension is a multifactorial disorder, which has been associated with the reduction in baroreflex sensitivity (BRS) and autonomic dysfunction. Several studies have revealed that increased reactive oxygen species (ROS) generated by nicotinamide adenine dinucleotide phosphate [NAD(P)H] oxidase, following activation of type 1 receptor (AT1R) by Angiotensin-(Ang) II, the main peptide of the Renin–Angiotensin–Aldosterone System (RAAS), is the central mechanism involved in Ang-II-derived hypertension. In the present review, we will discuss the role of Ang II and oxidative stress in hypertension, the relationship between the BRS and the genesis of hypertension and how the oxidative stress triggers baroreflex dysfunction in several models of hypertension. Finally, we will describe some novel therapeutic drugs for improving the BRS during hypertension.

The new nitric oxide donor 2-nitrate-1,3-dibuthoxypropan alters autonomic function in spontaneously hypertensive rats.

Previously, we found that the nitrate synthesized from glycerin, 2-nitrate-1,3-dibuthoxypropan (NDBP), increased NO levels in rat aortic smooth muscle cells, inducing vasorelaxation in mesenteric artery. However, its effects on blood pressure and heart rate as well as on autonomic function were not investigated. This study evaluated the action of NDBP on these cardiovascular parameters in spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats. We found that NDBP causes a biphasic response: hypotension and bradycardia followed by hypertension and tachycardia in WKY and SHR rats. Atropine (2mg/kg) blunted the hypotension induced by NDBP (15 mg/kg) in WKY and SHR (-75 ± 9 vs -12 ± 3 mmHg, n=6; -101 ± 6 vs -7 ± 2 bpm, n=6; respectively, p<0.05) and the pressor response to the compound was potentiated. Furthermore, vagotomy reduced the bradycardia in WKY and SHR (-136 ± 8 vs -17 ± 2, n=4, p<0.05; -141 ± 9 vs -8 ± 2, n=6, p<0.05). Moreover, hexamethonium (30 mg/kg) reduced both bradycardia (-278 ± 23 vs -48 ± 3 in WKY; -285 ± 16 vs -27 ± 19 in SHR, n=4; p<0.05) and pressor response (28 ± 8 vs -9 ± 5-WKY, n=6; 42 ± 7 vs -19 ± 8-SHR, n=5; p<0.05). In addition, administration of methylene blue (4 mg/kg) attenuated the hypotensive and bradycardic responses to the NDBP in all groups. In conclusion, NDBP induces bradycardia by direct vagal stimulation and pressor response by increasing sympathetic outflow to the periphery.

Coconut oil supplementation and physical exercise improves baroreflex sensitivity and oxidative stress in hypertensive rats

The hypothesis that oral supplementation with virgin coconut oil (Cocos nucifera L.) and exercise training would improve impaired baroreflex sensitivity (BRS) and reduce oxidative stress in spontaneously hypertensive rats (SHR) was tested. Adult male SHR and Wistar Kyoto rats (WKY) were divided into 5 groups: WKY + saline (n = 8); SHR + saline (n = 8); SHR + coconut oil (2 mL·day(-1), n = 8); SHR + trained (n = 8); and SHR + trained + coconut oil (n = 8). Mean arterial pressure (MAP) was recorded and BRS was tested using phenylephrine (8 μg/kg, intravenous) and sodium nitroprusside (25 μg·kg(-1), intravenous). Oxidative stress was measured using dihydroethidium in heart and aorta. SHR + saline, SHR + coconut oil, and SHR + trained group showed higher MAP compared with WKY + saline (175 ± 6, 148 ± 6, 147 ± 7 vs. 113 ± 2 mm Hg; p < 0.05). SHR + coconut oil, SHR + trained group, and SHR + trained + coconut oil groups presented lower MAP compared with SHR + saline group (148 ± 6, 147 ± 7, 134 ± 8 vs. 175 ± 6 mm Hg; p < 0.05). Coconut oil combined with exercise training improved BRS in SHR compared with SHR + saline group (-2.47 ± 0.3 vs. -1.39 ± 0.09 beats·min(-1)·mm Hg(-1); p < 0.05). SHR + saline group showed higher superoxide levels when compared with WKY + saline (774 ± 31 vs. 634 ± 19 arbitrary units (AU), respectively; p < 0.05). SHR + trained + coconut oil group presented reduced oxidative stress compared with SHR + saline in heart (622 ± 16 vs. 774 ± 31 AU, p < 0.05). In aorta, coconut oil reduced oxidative stress in SHR compared with SHR + saline group (454 ± 33 vs. 689 ± 29 AU, p < 0.05). Oral supplementation with coconut oil combined with exercise training improved impaired BRS and reduced oxidative stress in SHR.

Alkaloids and Phenolic Compounds from Sida rhombifolia L. (Malvaceae) and Vasorelaxant Activity of Two Indoquinoline Alkaloids

The follow-up of phytochemical and pharmacological studies of Sida rhombifolia L. (Malvaceae) aims to strengthen the chemosystematics and pharmacology of Sida genera and support the ethnopharmacological use of this species as hypotensive herb. The present work reports phytoconstituents isolated and identified from aerial parts of S. rhombifolia by using chromatographic and spectroscopic methods. The study led to the isolation of scopoletin (1), scoporone (2), ethoxy-ferulate (3), kaempferol (4), kaempferol-3-O-β-d-glycosyl-6′′-α-d-rhamnose (5), quindolinone (6), 11-methoxy-quindoline (7), quindoline (8), and the cryptolepine salt (9). The alkaloids quindolinone (6) and cryptolepine salt (9) showed vasorelaxant activity in rodent isolated mesenteric arteries.

Brain Angiotensin-II-derived Reactive Oxygen Species: Implications for High Blood Pressure

Hypertension and its relation to free radicals have been matter of continuous research worldwide. This review is based on the premise that some forms of neurogenic hypertension is, in part, caused by the formation of Angiotensin- II (Ang II)-derived reactive oxygen species within the brain, especially in areas along the Subfornical Organ- Paraventricular Nucleus of the Hypothalamus-Rostral Ventrolateral Medulla pathway (SFO-PVN-RVLM pathway). Here we will discuss the recent contribution of our laboratory and others regarding the mechanisms by which neurons in the Rostral Ventrolateral Medulla (RVLM) are activated by Ang II, how they communicate with the SFO and PVN and more importantly, how Ang II-derived Reactive Oxygen Species (ROS) participate along the SFO-PVN-RVLM pathway in the pathogenesis of neurogenic hypertension.

Antioxidant and Antihypertensive Effects of a Chemically Defined Fraction of Syrah Red Wine on Spontaneously Hypertensive Rats

A particularly phenolic-rich fraction extracted from red wine from the São Francisco valley (Northeastern Brazil) was chemically characterized and its hypotensive and antioxidant effects on spontaneously hypertensive rats were studied both in vitro and in vivo. The liquid-liquid pH dependent fractionation scheme afforded a fraction with high content of bioactive phenolics such as flavonols, flavonol glycosides, phenolic acids and anthocyanins, whose identities were confirmed by liquid chromatography coupled to mass spectrometry analysis. Pretreatment of spontaneously hypertensive rats with this wine fraction at doses of 50 and 100 mg/kg by gavage for 15 days was able to decrease mean arterial pressure and heart rate as well as decrease serum lipid peroxidation. The fraction at concentrations of 0.01–1000 µg/mL induced concentration-dependent relaxation of isolated rat superior mesenteric artery rings pre-contracted with phenylephrine and this effect was not attenuated by endothelium removal. Our results demonstrate it is possible for phenolic constituents of red wine that are orally bioavailable to exert in vivo hypotensive and antioxidant effects on intact endothelial function.

Cronic creatine supplementation and physical exercisereduces on oxidative stress in Wistar rats

Methods Twenty-four rats were divided into three groups: control (CO, n = 8), creatine supplemented (CR, n = 8; 0.5g creatine/kg/day, by gavage for 4 weeks) and exercise (EX, n = 8; swimming for 1 h/d, for 4 weeks). Oxidative stress was measured by tiobarbituric acid reactive species assay (TBARS) in serum, heart, kidney, liver, gastrocnemius muscle and nervous system (cortex, midbrain, cerebellum and brainstem).

Coconut oil supplementation reduces blood pressure and oxidative stress in spontaneously hypertensive rats

Background Oxidative stress has been implicated in the pathogenesis of hypertension and antioxidant compounds have been used in the prevention and treatment of this disease. In this context, coconut oil (CO) was found to have antioxidant property due to its high polyphenol content. In this study, we investigated the effects caused by chronic treatment with CO on mean arterial pressure (MAP), heart rate (HR), and lipid peroxidation in spontaneously hypertensive rats (SHR).