Quercetin: a treatment for hypertension? - a review of efficacy and mechanisms

Journal ArticleQuercetin is a polyphenolic flavonoid. Common sources in the diet are apples, onions, berries, and red wine. Epidemiological studies have found an inverse relationship between dietary quercetin intake and cardiovascular disease. This has led to in vitro, in vivo, and clinical research to determine the mechanism by which quercetin exerts cardioprotective effects. Recent studies have found a reduction in blood pressure when hypertensive (>140 mm Hg systolic and >90 mm Hg diastolic) animals and humans are supplemented with quercetin. Proposed mechanisms for the antihypertensive effect of quercetin include decreased oxidative stress, inhibition of angiotensin converting enzyme activity, improved endothelial function, direct action on the vascular smooth muscle, and/or modulation in cell signaling and gene expression. Although in vitro and in vivo evidence exists to support and refute each possibility, it is likely that quercetin influences multiple targets via a combination of known and as yet undiscovered mechanisms. The purpose of this review is to examine the mechanisms whereby quercetin might reduce blood pressure in hypertensive individuals

Risk factors for surgical site infection after cholecystectomy

AbstractBackgroundThere are limited data on risk factors for surgical site infection (SSI) after open or laparoscopic cholecystectomy.MethodsA retrospective cohort of commercially insured persons aged 18–64 years was assembled using International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedure or Current Procedural Terminology, 4th edition codes for cholecystectomy from December 31, 2004 to December 31, 2010. Complex procedures and patients (eg, cancer, end-stage renal disease) and procedures with pre-existing infection were excluded. Surgical site infections within 90 days after cholecystectomy were identified by ICD-9-CM diagnosis codes. A Cox proportional hazards model was used to identify independent risk factors for SSI.ResultsSurgical site infections were identified after 472 of 66566 (0.71%) cholecystectomies; incidence was higher after open (n = 51, 4.93%) versus laparoscopic procedures (n = 421, 0.64%; P &amp;lt; .001). Independent risk factors for SSI included male gender, preoperative chronic anemia, diabetes, drug abuse, malnutrition/weight loss, obesity, smoking-related diseases, previous Staphylococcus aureus infection, laparoscopic approach with acute cholecystitis/obstruction (hazards ratio [HR], 1.58; 95% confidence interval [CI], 1.27–1.96), open approach with (HR, 4.29; 95% CI, 2.45–7.52) or without acute cholecystitis/obstruction (HR, 4.04; 95% CI, 1.96–8.34), conversion to open approach with (HR, 4.71; 95% CI, 2.74–8.10) or without acute cholecystitis/obstruction (HR, 7.11; 95% CI, 3.87–13.08), bile duct exploration, postoperative chronic anemia, and postoperative pneumonia or urinary tract infection.ConclusionsAcute cholecystitis or obstruction was associated with significantly increased risk of SSI with laparoscopic but not open cholecystectomy. The risk of SSI was similar for planned open and converted procedures. These findings suggest that stratification by operative factors is important when comparing SSI rates between facilities.</jats:sec

Exercise training improves vascular mitochondrial function

Exercise training is recognized to improve cardiac and skeletal muscle mitochondrial respiratory capacity; however, the impact of chronic exercise on vascular mitochondrial respiratory function is unknown. We hypothesized that exercise training concomitantly increases both vascular mitochondrial respiratory capacity and vascular function. Arteries from both sedentary (SED) and swim-trained (EX, 5 wk) mice were compared in terms of mitochondrial respiratory function, mitochondrial content, markers of mitochondrial biogenesis, redox balance, nitric oxide (NO) signaling, and vessel function. Mitochondrial complex I and complex I + II state 3 respiration and the respiratory control ratio (complex I + II state 3 respiration/complex I state 2 respiration) were greater in vessels from EX relative to SED mice, despite similar levels of arterial citrate synthase activity and mitochondrial DNA content. Furthermore, compared with the SED mice, arteries from EX mice displayed elevated transcript levels of peroxisome proliferative activated receptor-γ coactivator-1α and the downstream targets cytochrome c oxidase subunit IV isoform 1, isocitrate dehydrogenase (Idh) 2, and Idh3a, increased manganese superoxide dismutase protein expression, increased endothelial NO synthase phosphorylation (Ser1177), and suppressed reactive oxygen species generation (all P \u3c 0.05). Although there were no differences in EX and SED mice concerning endothelium-dependent and endothelium-independent vasorelaxation, phenylephrine-induced vasocontraction was blunted in vessels from EX compared with SED mice, and this effect was normalized by NOS inhibition. These training-induced increases in vascular mitochondrial respiratory capacity and evidence of improved redox balance, which may, at least in part, be attributable to elevated NO bioavailability, have the potential to protect against age- and disease-related challenges to arterial function

α1-Adrenergic responsiveness in human skeletal muscle feed arteries: the impact of reducing extracellular pH

What is the central question of this study? In human arteries involved in the regulation of muscle blood flow, there is a lack of data about whether acidosis alters vascular sensitivity to vasoactive agents, as well as altering endothelium dependent vasorelaxation. Little is known about the interaction of metabolites and vascular function in human skeletal muscle feed arteries. • What is the main finding and its importance? Increasing acidosis attenuated the response and sensitivity of the arteries to phenylephrine; this effect was selective to the receptor over smooth muscle. Acidosis did not alter endothelium dependent vasorelaxation. Impaired vasoconstriction coupled with intact vasorelaxation, promotes decreased vascular tone with exposure to acidosis, and may contribute to sympatholysis during exercise

Shaping electron wave functions in a carbon nanotube with a parallel magnetic field

A magnetic field, through its vector potential, usually causes measurable changes in the electron wave function only in the direction transverse to the field. Here we demonstrate experimentally and theoretically that in carbon nanotube quantum dots, combining cylindrical topology and bipartite hexagonal lattice, a magnetic field along the nanotube axis impacts also the longitudinal profile of the electronic states. With the high (up to 17T) magnetic fields in our experiment the wave functions can be tuned all the way from "half-wave resonator" shape, with nodes at both ends, to "quarter-wave resonator" shape, with an antinode at one end. This in turn causes a distinct dependence of the conductance on the magnetic field. Our results demonstrate a new strategy for the control of wave functions using magnetic fields in quantum systems with nontrivial lattice and topology.Comment: 5 figure

Interleukin-1 regulates multiple atherogenic mechanisms in response to fat feeding

Background: Atherosclerosis is an inflammatory process that develops in individuals with known risk factors that include hypertension and hyperlipidaemia, influenced by diet. However, the interplay between diet, inflammatory mechanisms and vascular risk factors requires further research. We hypothesised that interleukin-1 (IL-1) signaling in the vessel wall would raise arterial blood pressure and promote atheroma. Methodology/Principal Findings: Apoe(-/-) and Apoe(-/-)/IL-1R1(-/-) mice were fed high fat diets for 8 weeks, and their blood pressure and atherosclerosis development measured. Apoe(-/-)/IL-R1(-/-) mice had a reduced blood pressure and significantly less atheroma than Apoe(-/-) mice. Selective loss of IL-1 signaling in the vessel wall by bone marrow transplantation also reduced plaque burden (p<0.05). This was associated with an IL-1 mediated loss of endothelium-dependent relaxation and an increase in vessel wall Nox 4. Inhibition of IL-1 restored endothelium-dependent vasodilatation and reduced levels of arterial oxidative stress. Conclusions/Significance: The IL-1 cytokine system links atherogenic environmental stimuli with arterial inflammation, oxidative stress, increased blood pressure and atherosclerosis. This is the first demonstration that inhibition of a single cytokine can block the rise in blood pressure in response to an environmental stimulus. IL-1 inhibition may have profound beneficial effects on atherogenesis in man

Romantic jealousy: a test of social cognitive and evolutionary models in a population-representative sample of adults

Whereas sexually dimorphic evolutionary models argue for clear sex differences in responses to jealousy-evoking scenarios, social cognitive models emphasize the importance of other factors. This paper explores variables associated with responses to a commonly-used jealousy-evoking scenario in a population-representative sample. Data from 8,386 Australian men and women aged 16-69 were weighted to match the population. The results provided some support for evolutionary models among heterosexual respondents, but findings contrary to evolutionary models were found among non-heterosexual respondents. Support for social cognitive models was provided by the identification of six variables that had significant independent multivariate associations with jealousy: sex, age, education, lifetime number of partners, relationship status, and attitudes toward infidelity. The results suggest that although men and women may tend to respond differently to sexual or emotional infidelity scenarios, the anticipated experience of jealousy in each context is strongly influenced by biographical and cultural factors

Increased dihydroceramide/ceramide ratio mediated by defective expression of degs1 impairs adipocyte differentiation and function.

Adipose tissue dysfunction is an important determinant of obesity-associated, lipid-induced metabolic complications. Ceramides are well-known mediators of lipid-induced insulin resistance in peripheral organs such as muscle. DEGS1 is the desaturase catalyzing the last step in the main ceramide biosynthetic pathway. Functional suppression of DEGS1 activity results in substantial changes in ceramide species likely to affect fundamental biological functions such as oxidative stress, cell survival, and proliferation. Here, we show that degs1 expression is specifically decreased in the adipose tissue of obese patients and murine models of genetic and nutritional obesity. Moreover, loss-of-function experiments using pharmacological or genetic ablation of DEGS1 in preadipocytes prevented adipogenesis and decreased lipid accumulation. This was associated with elevated oxidative stress, cellular death, and blockage of the cell cycle. These effects were coupled with increased dihydroceramide content. Finally, we validated in vivo that pharmacological inhibition of DEGS1 impairs adipocyte differentiation. These data identify DEGS1 as a new potential target to restore adipose tissue function and prevent obesity-associated metabolic disturbances.This work was funded by Medical Research Council, MDU MRC, FP7- ETHERPATHS and the British Heart Foundation (BHF). We declare no conflict of interest.This is the accepted manuscript. The final version is available from ADA at http://diabetes.diabetesjournals.org/content/early/2014/10/22/db14-0359.abstract