Sural nerve involvement in experimental hypertension: morphology and morphometry in male and female normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR)

Background: The sural nerve has been widely investigated in experimental models of neuropathies but information about its involvement in hypertension was not yet explored. The aim of the present study was to compare the morphological and morphometric aspects of different segments of the sural nerve in male and female spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats. Rats aged 20 weeks (N = 6 in each group) were investigated. After arterial pressure and heart rate recordings in anesthetized animals, right and left sural nerves were removed and prepared for epoxy resin embedding and light microscopy. Morphometric analysis was performed with the aid of computer software, and took into consideration the fascicle area and diameter, as well as myelinated fiber number, density, area and diameter. Results: Significant differences were observed for the myelinated fiber number and density, comparing different genders of WKY and SHR. Also, significant differences for the morphological (thickening of the endoneural blood vessel walls and lumen reduction) and morphometric (myelinated fibers diameter and G ratio) parameters of myelinated fibers were identified. Morphological exam of the myelinated fibers suggested the presence of a neuropathy due to hypertension in both SHR genders. Conclusions: These results indicate that hypertension altered important morphometric parameters related to nerve conduction of sural nerve in hypertensive animals. Moreover the comparison between males and females of WKY and SHR allows the conclusion that the morphological and morphometric parameters of sural nerve are not gender related. The morphometric approach confirmed the presence of neuropathy, mainly associated to the small myelinated fibers. In conclusion, the present study collected evidences that the high blood pressure in SHR is affecting the sural nerve myelinated fibers.

Fluctuating Initial Conditions and Anisotropic Flows

In this work we study the connection between anisotropic flows and lumpy initial conditions for Au+Au collisions at 200 GeV. We present comparisons between anisotropic flow coefficients and eccentricities up to sixth order, and between initial condition reference angles and azimuthal particle distribution angles. We also present a toy model to justify the lack of connection between flow coefficients and eccentricities for individual events.

GLUT4 content decreases along with insulin resistance and high levels of inflammatory markers in rats with metabolic syndrome

Background: Metabolic syndrome is characterized by insulin resistance, which is closely related to GLUT4 content in insulin-sensitive tissues. Thus, we evaluated the GLUT4 expression, insulin resistance and inflammation, characteristics of the metabolic syndrome, in an experimental model. Methods: Spontaneously hypertensive neonate rats (18/group) were treated with monosodium glutamate (MetS) during 9 days, and compared with Wistar-Kyoto (C) and saline-treated SHR (H). Blood pressure (BP) and lipid levels, C-reactive protein (CRP), interleukin 6 (IL-6), TNF-alpha and adiponectin were evaluated. GLUT4 protein was analysed in the heart, white adipose tissue and gastrocnemius. Studies were performed at 3 (3-mo), 6 (6-mo) and 9 (9-mo) months of age. Results: MetS rats were more insulin resistant (p<0.001, all ages) and had higher BP (3-mo: p<0.001, 6-mo: p = 0.001, 9-mo: p = 0.015) as compared to C. At 6 months, CRP, IL-6 and TNF-alpha were higher (p<0.001, all comparisons) in MetS rats vs H, but adiponectin was lower in MetS at 9 months (MetS: 32 +/- 2, H: 42 +/- 2, C: 45 +/- 2 pg/mL; p<0.001). GLUT4 protein was reduced in MetS as compared to C rats at 3, 6 and 9-mo, respectively (Heart: 54%, 50% and 57%; Gastrocnemius: 37%, 56% and 50%; Adipose tissue: 69%, 61% and 69%). Conclusions: MSG-treated SHR presented all metabolic syndrome characteristics, as well as reduced GLUT4 content, which must play a key role in the impaired glycemic homeostasis of the metabolic syndrome.

Arterial Spin Labeling Measurements of Cerebral Perfusion Territories in Experimental Ischemic Stroke

Collateral circulation, defined as the supplementary vascular network that maintains cerebral blood flow (CBF) when the main vessels fail, constitutes one important defense mechanism of the brain against ischemic stroke. In the present study, continuous arterial spin labeling (CASL) was used to quantify CBF and obtain perfusion territory maps of the major cerebral arteries in spontaneously hypertensive rats (SHRs) and their normotensive Wistar-Kyoto (WKY) controls. Results show that both WKY and SHR have complementary, yet significantly asymmetric perfusion territories. Right or left dominances were observed in territories of the anterior (ACA), middle and posterior cerebral arteries, and the thalamic artery. Magnetic resonance angiography showed that some of the asymmetries were correlated with variations of the ACA. The leptomeningeal circulation perfusing the outer layers of the cortex was observed as well. Significant and permanent changes in perfusion territories were obtained after temporary occlusion of the right middle cerebral artery in both SHR and WKY, regardless of their particular dominance. However, animals with right dominance presented a larger volume change of the left perfusion territory (23 +/- 9%) than animals with left dominance (7 +/- 5%, P<0.002). The data suggest that animals with contralesional dominance primarily safeguard local CBF values with small changes in contralesional perfusion territory, while animals with ipsilesional dominance show a reversal of dominance and a substantial increase in contralesional perfusion territory. These findings show the usefulness of CASL to probe the collateral circulation.

STIM 1/Orai 1 contributes to sex differences in vascular responses to calcium in spontaneously hypertensive rats

Sex differences in Ca2+-dependent signalling and homoeostasis in the vasculature of hypertensive rats are well characterized. However, sex-related differences in SOCE (store-operated Ca2+ entry) have been minimally investigated. We hypothesized that vascular protection in females, compared with males, reflects decreased Ca2+ mobilization due to diminished activation of Orai 1/STIM 1 (stromal interaction molecule I). In addition, we investigated whether ovariectomy in females affects the activation of the Orai 1/STIM 1 pathway. Endothelium-denuded aortic rings from male and female SHRSP (stroke-prone spontaneously hypertensive rats) and WKY (Wistar Kyoto) rats and from OVX (ovariectomized) or sham female SHRSP and WKY rats were used to functionally evaluate Ca2+ influx-induced contractions. Compared with females, aorta from male SHRSP displayed: (i) increased contraction during the Ca2+-loading period; (ii) similar transient contraction during Ca2+ release from the intracellular stores; (iii) increased activation of STIM 1 and Orai1, as shown by the blockade of STIM 1 and Orai1 with neutralizing antibodies, which reversed the sex differences in contraction during the Ca2+-loading period; and (iv) increased expression of STIM I and Orai I. Additionally, we found that aortas from OVX-SHRSP showed increased contraction during the Ca2+-loading period and increased Orai1 expression, but no changes in the SR (sarcoplasmic reticulum)-buffering capacity or STIM I expression. These findings suggest that augmented activation of STIM 1/Orai 1 in aortas from male SHRSP represents a mechanism that contributes to sex-related impaired control of intracellular Ca2+ levels. Furthermore, female sex hormones may negatively modulate the STIM/Orai 1 pathway, contributing to vascular protection observed in female rats.

AEROBIC EXERCISE TRAINING CORRECTS CAPILLARY RAREFACTION AND ALTERATIONS IN PROPORTIONS OF THE MUSCLE FIBERS TYPES IN SPONTANEOUSLY HYPERTENSIVE RATS

Aerobic exercise training (ET) has been established as an important non-pharmacological treatment of hypertension, since it decreases blood pressure. Studies show that the skeletal muscle abnormalities in hypertension are directly associated with capillary rarefaction, higher percentage of fast-twitch fibers (type II) with glycolytic metabolism predominance and increased muscular fatigue. However, little is known about these parameters in hypertension induced by ET. We hypothesized that ET corrects capillary rarefaction, potentially contributing to the restoration of the proportion of muscle fiber types and metabolic proprieties. Twelve-week old Spontaneously Hypertensive Rats (SHR, n=14) and Wistar Kyoto rats (WKY, n=14) were randomly assigned into 4 groups: SHR, trained SHR (SHR-T), WKY and trained WKY (WKY-T). As expected, ten weeks of ET was effective in reducing blood pressure in SHR-T group. In addition, we analyzed the main markers of ET. Resting bradycardia, increase of exercise tolerance, peak oxygen uptake and citrate synthase enzyme activity in trained groups (WKY-T and SHR-T) showed that the aerobic condition was achieved. ET also corrected the skeletal muscle capillary rarefaction in SHR-T. In parallel, we observed reduction in percentage of type IIA and IIX fibers and simultaneous augmented percentage of type I fibers induced by ET in hypertension. These data suggest that ET prevented changes in soleus fiber type composition in SHR, since angiogenesis and oxidative enzyme activity increased are important adaptations of ET, acting in the maintenance of muscle oxidative metabolism and fiber profile.

Exercise training restores the endothelial progenitor cells number and function in hypertension: implications for angiogenesis

Objectives: Aerobic exercise training has been established as an important nonpharmacological treatment for hypertension. We investigated whether the number and function of endothelial progenitor cells (EPCs) are restored after exercise training, potentially contributing to neovascularization in hypertension. Methods: Twelve-week-old male spontaneously hypertensive rats (SHRs, n = 14) and Wistar Kyoto (WKY, n = 14) rats were assigned to four groups: SHR; trained SHR (SHR-T); WKY; and trained WKY. Exercise training consisted of 10 weeks of swimming. EPC number and function, as well as the vascular endothelial growth factor (VEGF), nitrotyrosine and nitrite concentration in peripheral blood were quantified by fluorescence-activated cell sorter analysis (CD34+/Flk1+ cells), colony-forming unit assay, ELISA and nitric oxide (NO) analyzer, respectively. Soleus capillary/fiber ratio and protein expression of VEGF and endothelial NO synthase (eNOS) by western blot were assessed. Results: Exercise training was effective in reducing blood pressure in SHR-T accompanied by resting bradycardia, an increase in exercise tolerance, peak oxygen uptake (VO2) and citrate synthase activity. In response to hypertension, the amount of peripheral blood-EPC and number of colonies were decreased in comparison with control levels. In contrast, exercise training normalized the EPC levels and function in SHR-T accompanied by an increase in VEGF and NO levels. In addition, oxidative stress levels were normalized in SHR-T. Similar results were found in the number and function of bone marrow EPC. Exercise training repaired the peripheral capillary rarefaction in hypertension by a signaling pathway VEGF/eNOS-dependent in SHR-T. Moreover, improvement in EPC was significantly related to angiogenesis. Conclusion: Our data show that exercise training repairs the impairment of EPC in hypertension, which could be associated with peripheral revascularization, suggesting a mechanism for its potential therapeutic: application in vascular diseases.

Testosterone Induces Vascular Smooth Muscle Cell Migration by NADPH Oxidase and c-Src-Dependent Pathways

Testosterone has been implicated in vascular remodeling associated with hypertension. Molecular mechanisms underlying this are elusive, but oxidative stress may be important. We hypothesized that testosterone stimulates generation of reactive oxygen species (ROS) and migration of vascular smooth muscle cells (VSMCs), with enhanced effects in cells from spontaneously hypertensive rats (SHRs). The mechanisms (genomic and nongenomic) whereby testosterone induces ROS generation and the role of c-Src, a regulator of redox-sensitive migration, were determined. VSMCs from male Wistar-Kyoto rats and SHRs were stimulated with testosterone (10(-7) mol/L, 0-120 minutes). Testosterone increased ROS generation, assessed by dihydroethidium fluorescence and lucigenin-enhanced chemiluminescence (30 minutes [SHR] and 60 minutes [both strains]). Flutamide (androgen receptor antagonist) and actinomycin D (gene transcription inhibitor) diminished ROS production (60 minutes). Testosterone increased Nox1 and Nox4 mRNA levels and p47phox protein expression, determined by real-time PCR and immunoblotting, respectively. Flutamide, actinomycin D, and cycloheximide (protein synthesis inhibitor) diminished testosterone effects on p47phox. c-Src phosphorylation was observed at 30 minutes (SHR) and 120 minutes (Wistar-Kyoto rat). Testosterone-induced ROS generation was repressed by 3-(4-chlorophenyl) 1-(1,1-dimethylethyl)-1H-pyrazolo[3,4-day]pyrimidin-4-amine (c-Src inhibitor) in SHRs and reduced by apocynin (antioxidant/NADPH oxidase inhibitor) in both strains. Testosterone stimulated VSMCs migration, assessed by the wound healing technique, with greater effects in SHRs. Flutamide, apocynin, and 3-(4-chlorophenyl) 1-(1,1-dimethylethyl)-1H-pyrazolo[3,4-day] pyrimidin-4-amine blocked testosterone-induced VSMCs migration in both strains. Our study demonstrates that testosterone induces VSMCs migration via NADPH oxidase-derived ROS and c-Src-dependent pathways by genomic and nongenomic mechanisms, which are differentially regulated in VSMCs from Wistar-Kyoto rats and SHRs. (Hypertension. 2012; 59: 1263-1271.). Online Data Supplement

Exercise training prevents the microvascular rarefaction in hypertension balancing angiogenic and apoptotic factors role of microRNAs-16,-21, and -126

Aerobic exercise training (ET) lowers hypertension and improves patient outcomes in cardiovascular disease. The mechanisms of these effects are largely unknown. We hypothesized that ET modulates microRNAs (miRNAs) involved in vascularization. miRNA-16 regulates the expression of vascular endothelial growth factor and antiapoptotic protein Bcl-2. miRNA-21 targets Bcl-2. miRNA-126 functions by repressing regulators of the vascular endothelial growth factor pathway. We investigated whether miRNA-16, -21 and -126 are modulated in hypertension and by ET. Twelve-week-old male spontaneously hypertensive rats (SHRs; n=14) and Wistar Kyoto (WKY; n=14) rats were assigned to 4 groups: SHRs, trained SHRs (SHR-T), Wistar Kyoto rats, and trained Wistar Kyoto rats. ET consisted of 10 weeks of swimming. ET reduced blood pressure and heart rate in SHR-Ts. ET repaired the slow-to-fast fiber type transition in soleus muscle and the capillary rarefaction in SHR-Ts. Soleus miRNA-16 and -21 levels increased in SHRs paralleled with a decrease of 48% and 25% in vascular endothelial growth factor and Bcl-2 protein levels, respectively. Hypertension increased Bad and decreased Bcl-x and endothelial NO synthase levels and lowered p-Bad(ser112): Bad ratio. ET in SHR-Ts reduced miRNA-16 and -21 levels and elevated vascular endothelial growth factor and Bcl-2 levels. ET restored soleus endothelial NO synthase levels plus proapoptotic and antiapoptotic mediators in SHR-Ts, indicating that the balance between angiogenic and apoptotic factors may prevent microvascular abnormalities in hypertension. miRNA-126 levels were reduced in SHRs with an increase of 51% in phosphoinositol-3 kinase regulatory subunit 2 expression but normalized in SHR-Ts. Our data show that ET promoted peripheral revascularization in hypertension, which could be associated with regulation of select miRNAs, suggesting a mechanism for its potential therapeutic application in vascular diseases. (Hypertension. 2012;59[part 2]:513-520.). Online Data Supplement

On the Origin of the Trigger-Angle Dependence of the Ridge Structure

The origin of the trigger-angle dependence of the ridge structure in two-hadron long-range correlations, as observed at RHIC, is discussed as due to an interplay between the elliptic flow caused by the initial state global geometry and flow produced by fluctuations.

Alpha(2)-adrenergic receptor distribution and density within the nucleus tractus solitarii of normotensive and hypertensive rats during development

The nucleus tractus solitarii (NTS), located in the brainstem, is one of the main nuclei responsible for integrating different signals in order to originate a specific and orchestrated autonomic response. Antihypertensive drugs are well known to stimulate alpha(2)-adrenoceptor (alpha(2R)) in brainstem cardiovascular regions to induce reduction in blood pressure. Because alpha(2R) impairment is present in several models of hypertension, the aim of the present study was to investigate the distribution and density of alpha(2R) binding within the NTS of Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats during development (1,15,30 and 90 day-old) by an in vitro autoradiographical study. The NTS shows heterogeneous distribution of alpha(2R) in dorsomedial/dorsolateral, subpostremal and medial/intermediate subnuclei. Alpha(2R) increased from rostral to caudal dorsomedial/dorsolateral subnuclei in 30 and 90 day-old SHR but not in WKY. Alpha(2R) decreased from rostral to caudal subpostremal subnucleus in 15, 30 and 90 day-old SHR but not in WKY. Medial/intermediate subnuclei did not show any changes in alpha(2R) according to NTS levels. Furthermore, alpha(2R) are decreased in SHR as compared with WKY in all NTS subnuclei and in different ages. Surprisingly, alpha(2R) impairment was also found in pre-hypertensive stages, specifically in subpostremal subnucleus of 15 day-old rats. Finally, alpha(2R) decrease from 1 to 90 day-old rats in all subnuclei analyzed. This decrease is different between strains in rostral dorsomedial/dorsolateral and caudal subpostremal subnuclei within the NTS. In summary, our results highlight the importance of alpha(2R) distribution within the NTS regarding the neural control of blood pressure and the development of hypertension. (C) 2011 Elsevier B.V. All rights reserved.

Identification of epsilon PKC Targets During Cardiac Ischemic Injury

Background: Epsilon-protein kinase C (epsilon PKC) protects the heart from ischemic injury. However, the mechanism(s) of epsilon PKC cardioprotection is still unclear. Identification of the epsilon PKC targets may aid in elucidating the epsilon PKC-mediated cardioprotective mechanisms. Previous studies, using epsilon PKC transgenic mice and difference in gel electrophoresis, identified proteins involved in glucose metabolism, the expression of which was modified by epsilon PKC. Those studies were accompanied by metabolomic analysis, suggesting that increased glucose oxidation may be responsible for the cardioprotective effect of epsilon PKC. Whether these epsilon PKC-mediated alterations were because of differences in protein expression or phosphorylation was not determined. Methods and Results: In the present study, we used an epsilon PKC -specific activator peptide, psi epsilon RACK, combined with phosphoproteomics, to find epsilon PKC targets, and identified that the proteins whose phosphorylation was altered by selective activation of epsilon PKC were mostly mitochondrial proteins. Analysis of the mitochondrial phosphoproteome led to the identification of 55 spots, corresponding to 37 individual proteins, exclusively phosphorylated, in the presence of psi epsilon RACK. The majority of the proteins identified were involved in glucose and lipid metabolism, components of the respiratory chain as well as mitochondrial heat shock proteins. Conclusions: The protective effect of epsilon PKC during ischemia involves phosphorylation of several mitochondrial proteins involved in glucose and lipid metabolism and oxidative phosphorylation. Regulation of these metabolic pathways by epsilon PKC phosphorylation may lead to epsilon PKC-mediated cardioprotection induced by psi epsilon RACK. (Circ J 2012; 76: 1476-1485)

CARBON MARKET AND INSTITUTIONS: OPPORTUNITIES IN THE SEARCH OF A NEW MODEL FOR DEVELOPMENT

Seeking alternatives for the economic system to face the several crises it has gone through lately (electrical power, cultural, financing and technological) brought about a new market involving the Kyoto Protocol signatory countries: the carbon market. The present article aims at assessing the carbon market institutional issue in Brazil by identifying the risks and opportunities inherent to the institutional agent characteristics and to that market rules. The research methodology was bibliographic and based on the analysis of the Securities and Exchange Commission of Brazil (Comissao de Valores Mobiliarios and Bolsa Mercantil de Valores) contents. Its theoretical basis rests on concepts of the institution and the new institutional economy. The results show that in spite of the risks and institutional problems it involves, the carbon market is promising due to the opportunities create by new technologies and energies developed to achieve and sustain the capitalist system new cycle, addressed to produce a clean development.

Exercise training normalizes an increased neuronal excitability of NTS-projecting neurons of the hypothalamic paraventricular nucleus in hypertensive rats

Stern JE, Sonner PM, Son SJ, Silva FC, Jackson K, Michelini LC. Exercise training normalizes an increased neuronal excitability of NTS-projecting neurons of the hypothalamic paraventricular nucleus in hypertensive rats. J Neurophysiol 107: 2912-2921, 2012. First published February 22, 2012; doi:10.1152/jn.00884.2011.-Elevated sympathetic outflow and altered autonomic reflexes, including impaired baroreflex function, are common findings observed in hypertensive disorders. Although a growing body of evidence supports a contribution of preautonomic neurons in the hypothalamic paraventricular nucleus (PVN) to altered autonomic control during hypertension, the precise underlying mechanisms remain unknown. Here, we aimed to determine whether the intrinsic excitability and repetitive firing properties of preautonomic PVN neurons that innervate the nucleus tractus solitarii (PVN-NTS neurons) were altered in spontaneously hypertensive rats (SHR). Moreover, given that exercise training is known to improve and/or correct autonomic deficits in hypertensive conditions, we evaluated whether exercise is an efficient behavioral approach to correct altered neuronal excitability in hypertensive rats. Patch-clamp recordings were obtained from retrogradely labeled PVN-NTS neurons in hypothalamic slices obtained from sedentary (S) and trained (T) Wistar-Kyoto (WKY) and SHR rats. Our results indicate an increased excitability of PVN-NTS neurons in SHR-S rats, reflected by an enhanced input-output function in response to depolarizing stimuli, a hyperpolarizing shift in Na+ spike threshold, and smaller hyperpolarizing afterpotentials. Importantly, we found exercise training in SHR rats to restore all these parameters back to those levels observed in WKY-S rats. In several cases, exercise evoked opposing effects in WKY-S rats compared with SHR-S rats, suggesting that exercise effects on PVN-NTS neurons are state dependent. Taken together, our results suggest that elevated preautonomic PVN-NTS neuronal excitability may contribute to altered autonomic control in SHR rats and that exercise training efficiently corrects these abnormalities.