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Santos KGD, Yoshinaga MY, Glezer I, Chaves-Filho ADB, Santana AAD, Kovacs C, Magnoni CD, Lajolo FM, Miyamoto S, Aymoto Hassimotto NM. Orange juice intake by obese and insulin-resistant subjects lowers specific plasma triglycerides: A randomized clinical trial. Clin Nutr ESPEN 2022; 51:336-344. [DOI: 10.1016/j.clnesp.2022.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 07/24/2022] [Accepted: 08/03/2022] [Indexed: 11/26/2022]
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Wirt RA, Crew LA, Ortiz AA, McNeela AM, Flores E, Kinney JW, Hyman JM. Altered theta rhythm and hippocampal-cortical interactions underlie working memory deficits in a hyperglycemia risk factor model of Alzheimer's disease. Commun Biol 2021; 4:1036. [PMID: 34480097 PMCID: PMC8417282 DOI: 10.1038/s42003-021-02558-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 07/28/2021] [Indexed: 01/04/2023] Open
Abstract
Diabetes mellitus is a metabolic disease associated with dysregulated glucose and insulin levels and an increased risk of developing Alzheimer’s disease (AD) later in life. It is thought that chronic hyperglycemia leads to neuroinflammation and tau hyperphosphorylation in the hippocampus leading to cognitive decline, but effects on hippocampal network activity are unknown. A sustained hyperglycemic state was induced in otherwise healthy animals and subjects were then tested on a spatial delayed alternation task while recording from the hippocampus and anterior cingulate cortex (ACC). Hyperglycemic animals performed worse on long delay trials and had multiple electrophysiological differences throughout the task. We found increased delta power and decreased theta power in the hippocampus, which led to altered theta/delta ratios at the end of the delay period. Cross frequency coupling was significantly higher in multiple bands and delay period hippocampus-ACC theta coherence was elevated, revealing hypersynchrony. The highest coherence values appeared long delays on error trials for STZ animals, the opposite of what was observed in controls, where lower delay period coherence was associated with errors. Consistent with previous investigations, we found increases in phosphorylated tau in STZ animals’ hippocampus and cortex, which might account for the observed oscillatory and cognitive changes. To investigate the effects of chronic hyperglycemia on hippocampal network activity Wirt et al induced sustained hyperglycemia in rats and tested them in a spatial delayed alternation task while recording from the hippocampus and anterior cingulate cortex. They demonstrated that hyperglycemia impaired task performance and altered theta rhythm as well as increasing tau phosphorylation, which suggest there is potentially a direct link between chronic hyperglycemia and Alzheimer’s disease.
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Affiliation(s)
- Ryan A Wirt
- Interdisciplinary Program in Neuroscience, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Lauren A Crew
- Interdisciplinary Program in Neuroscience, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Andrew A Ortiz
- Interdisciplinary Program in Neuroscience, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Adam M McNeela
- Interdisciplinary Program in Neuroscience, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Emmanuel Flores
- Interdisciplinary Program in Neuroscience, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Jefferson W Kinney
- Department of Brain Health, School of Integrated Health Sciences, University of Nevada, Las Vegas, NV, USA
| | - James M Hyman
- Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV, USA.
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Haghi J, Eteraf-Oskouei T, Najafi M. Effects of Postconditioning with Fructose on Arrhythmias and the Size of Infarct Caused by Global Ischemia and Reperfusion in Isolated Rat Heart. Adv Pharm Bull 2018; 8:57-62. [PMID: 29670839 PMCID: PMC5896396 DOI: 10.15171/apb.2018.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 12/28/2017] [Accepted: 01/01/2018] [Indexed: 12/28/2022] Open
Abstract
Purpose: In the present study, postconditioning effect of fructose against ischemia/reperfusion (I/R)-induced arrhythmias and infarct size were investigated in isolated rat heart. Methods: The isolated hearts were divided into 7 groups, mounted on a Langendorff apparatus at constant pressure then subjected to 30 min zero flow global ischemia followed by 120 min reperfusion. In the control group, normal Krebs–Henseleit (K/H) solution was perfused into the hearts throughout the experiment. In two separate sets of experiments, the treatment groups received 12, 24 and 48 mM of fructose with/without normal glucose in K/H solution for 20 min at the beginning of reperfusion. Cardiac arrhythmias including number of ventricular tachycardia (VT), total ventricular ectopic beats, incidence and duration of VT, reversible and irreversible ventricular fibrillation were recorded and analyzed during the first 30 min of reperfusion. Computerized planimetry method was used to determine volume and percentage of infarct size. Results: Administration of fructose as a postconditioning agent clearly reduced volume and percentage of infarct size in the all treatment groups. The effect was statistically significant especially in the hearts that treated by fructose plus glucose (P<0.05). However, fructose alone or its co-administration with glucose had no significant inhibitory effect against reperfusion arrhythmias. Conclusion: The results showed that perfusion of high concentration of fructose alone or coincident with glucose in globally ischemic-reperfused isolated rat hearts can reduce infarct size without inhibitory effect against reperfusion arrhythmias. Probably, fructose by providing adequate ATP for cardiac functions may inhibit necrosis and death of cardiomyocytes during I/R.
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Affiliation(s)
- Jila Haghi
- Student Research Committee, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Tahereh Eteraf-Oskouei
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Moslem Najafi
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
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Mangmool S, Denkaew T, Parichatikanond W, Kurose H. β-Adrenergic Receptor and Insulin Resistance in the Heart. Biomol Ther (Seoul) 2017; 25:44-56. [PMID: 28035081 PMCID: PMC5207462 DOI: 10.4062/biomolther.2016.128] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/26/2016] [Accepted: 08/02/2016] [Indexed: 12/24/2022] Open
Abstract
Insulin resistance is characterized by the reduced ability of insulin to stimulate tissue uptake and disposal of glucose including cardiac muscle. These conditions accelerate the progression of heart failure and increase cardiovascular morbidity and mortality in patients with cardiovascular diseases. It is noteworthy that some conditions of insulin resistance are characterized by up-regulation of the sympathetic nervous system, resulting in enhanced stimulation of β-adrenergic receptor (βAR). Overstimulation of βARs leads to the development of heart failure and is associated with the pathogenesis of insulin resistance in the heart. However, pathological consequences of the cross-talk between the βAR and the insulin sensitivity and the mechanism by which βAR overstimulation promotes insulin resistance remain unclear. This review article examines the hypothesis that βARs overstimulation leads to induction of insulin resistance in the heart.
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Affiliation(s)
- Supachoke Mangmool
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand.,Center of Excellence for Innovation in Drug Design and Discovery, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand
| | - Tananat Denkaew
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand
| | | | - Hitoshi Kurose
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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DiNicolantonio JJ, Lucan SC. The wrong white crystals: not salt but sugar as aetiological in hypertension and cardiometabolic disease. Open Heart 2014; 1:e000167. [PMID: 25717381 PMCID: PMC4336865 DOI: 10.1136/openhrt-2014-000167] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Revised: 08/28/2014] [Accepted: 10/01/2014] [Indexed: 01/09/2023] Open
Abstract
Cardiovascular disease is the leading cause of premature mortality in the developed world, and hypertension is its most important risk factor. Controlling hypertension is a major focus of public health initiatives, and dietary approaches have historically focused on sodium. While the potential benefits of sodium-reduction strategies are debatable, one fact about which there is little debate is that the predominant sources of sodium in the diet are industrially processed foods. Processed foods also happen to be generally high in added sugars, the consumption of which might be more strongly and directly associated with hypertension and cardiometabolic risk. Evidence from epidemiological studies and experimental trials in animals and humans suggests that added sugars, particularly fructose, may increase blood pressure and blood pressure variability, increase heart rate and myocardial oxygen demand, and contribute to inflammation, insulin resistance and broader metabolic dysfunction. Thus, while there is no argument that recommendations to reduce consumption of processed foods are highly appropriate and advisable, the arguments in this review are that the benefits of such recommendations might have less to do with sodium-minimally related to blood pressure and perhaps even inversely related to cardiovascular risk-and more to do with highly-refined carbohydrates. It is time for guideline committees to shift focus away from salt and focus greater attention to the likely more-consequential food additive: sugar. A reduction in the intake of added sugars, particularly fructose, and specifically in the quantities and context of industrially-manufactured consumables, would help not only curb hypertension rates, but might also help address broader problems related to cardiometabolic disease.
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Affiliation(s)
- James J DiNicolantonio
- Department of Preventive Cardiology, Saint Luke's Mid America Heart Institute, Kansas City, Missouri, USA
| | - Sean C Lucan
- Department of Family and Social Medicine, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, USA
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El-Bassossy HM, Dsokey N, Fahmy A. Characterization of vascular complications in experimental model of fructose-induced metabolic syndrome. Toxicol Mech Methods 2014; 24:536-43. [PMID: 25046175 DOI: 10.3109/15376516.2014.945109] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Vascular dysfunction is an important complication associated with metabolic syndrome (MS). Here we fully characterized vascular complications in a rat model of fructose-induced MS. MS was induced by adding fructose (10%) to drinking water to male Wistar rats of 6 weeks age. Blood pressure (BP) and isolated aorta responses phenylephrine (PE), KCl, acetylcholine (ACh), and sodium nitroprusside (SNP) were recorded after 6, 9, and 12 weeks of fructose administration. In addition, serum levels of glucose, insulin, uric acid, tumor necrosis factor α (TNFα), lipids, advanced glycation end products (AGEs), and arginase activity were determined. Furthermore, aortic reactive oxygen species (ROS) generation, hemeoxygenase-1 expression, and collagen deposition were examined. Fructose administration resulted in a significant hyperinslinemia after 6 weeks which continued for 12 weeks. It was also associated with a significant increase in BP after 6 weeks which was stable for 12 weeks. Aorta isolated from MS animals showed exaggerated contractility to PE and KCl and impaired relaxation to ACh compared with control after 6 weeks which were clearer at 12 weeks of fructose administration. In addition, MS animals showed significant increases in serum levels of lipids, uric acid, AGEs, TNFα, and arginase enzyme activity after 12 weeks of fructose administration. Furthermore, aortae isolated from MS animals were characterized by increased ROS generation and collagen deposition. In conclusion, adding fructose (10%) to drinking water produces a model of MS with vascular complications after 12 weeks that are characterized by insulin resistance, hypertension, disturbed vascular reactivity and structure, hyperuricemia, dyslipidemia, and low-grade inflammation.
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Affiliation(s)
- Hany M El-Bassossy
- Department of Pharmacology, Faculty of Pharmacy, King Abdulaziz University , Jeddah , Kingdom of Saudi Arabia and
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Macedo AF, Douglas I, Smeeth L, Forbes H, Ebrahim S. Statins and the risk of type 2 diabetes mellitus: cohort study using the UK clinical practice pesearch datalink. BMC Cardiovasc Disord 2014; 14:85. [PMID: 25022519 PMCID: PMC4118294 DOI: 10.1186/1471-2261-14-85] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 07/07/2014] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND There is strong evidence of reductions in major vascular events from statins across all cardiovascular risk categories. However, trials of statin therapy have provided conflicting results regarding statin use and type 2 diabetes (T2DM). We aimed to assess the effect of statins on T2DM development. METHOD We carried out a population-based cohort study using the Clinical Practice Research Datalink (CPRD), a database of computerized clinical records. Every patient aged 30-85 years old starting a statin between 1989 and 2009 was matched with up to five non-statin users. The observation period in CPRD ended in 31 December 2011. Cox proportional hazard regression was used to compare rates of T2DM between statin users and non-users, using propensity score method to adjust for systematic differences between groups. RESULTS The study basis comprised 2,016,094 individuals, including 430,890 people who received a statin, matched to 1,585,204 people not prescribed a statin. Mean follow-up time was 5.43 years for statin users and 3.89 years for nonusers. During follow-up 130,395 individuals developed T2DM. Statin use was associated with an increased risk of T2DM (HR 1.57; 95% CI 1.54-1.59), which increases with longer duration of use. The increased risk was smaller among people with hypertension or cardiovascular disease and was only apparent after 5 or more years treatment with statins in these groups. Conversely, age-specific risk ratios decreased in older people. CONCLUSIONS Statin use is associated with an increased risk of T2DM. Our results suggest that the relative risk is higher among people without diagnosed hypertension or cardiovascular disease. These findings should be considered in the context of the observational nature of the data which is prone to bias and unmeasured confounding.
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Affiliation(s)
- Ana Filipa Macedo
- Department of Non-communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
- Faculty of Health Sciences, University of Beira Interior, Covilhã, Portugal
| | - Ian Douglas
- Department of Non-communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Liam Smeeth
- Department of Non-communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Harriet Forbes
- Department of Non-communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Shah Ebrahim
- Department of Non-communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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De Ciuceis C, Flati V, Rossini C, Rufo A, Porteri E, Di Gregorio J, Petroboni B, La Boria E, Donini C, Pasini E, Agabiti Rosei E, Rizzoni D. Effect of antihypertensive treatments on insulin signalling in lympho-monocytes of essential hypertensive patients: A pilot study. Blood Press 2014; 23:330-8. [DOI: 10.3109/08037051.2014.901021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Vasdev S, Stuckless J, Richardson V. Role of the immune system in hypertension: modulation by dietary antioxidants. Int J Angiol 2012. [PMID: 23204821 DOI: 10.1055/s-0031-1288941] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Hypertension is a major health problem worldwide. Individuals with hypertension are at an increased risk for stroke, heart disease, and kidney failure. Although the etiology of essential hypertension has a genetic component, lifestyle factors such as diet play an important role. Insulin resistance is a common feature of hypertension in both humans and animal models affecting glucose and lipid metabolism producing excess aldehydes including methylglyoxal. These aldehydes react with proteins to form conjugates called advanced glycation end products (AGEs). This alters protein structure and function and can affect vascular and immune cells leading to their activation and secretion of inflammatory cytokines. AGEs also act via receptors for advanced glycation end products on these cells altering the function of antioxidant and metabolic enzymes, and ion channels. This results in an increase in cytosolic free calcium, decrease in nitric oxide, endothelial dysfunction, oxidative stress, peripheral vascular resistance, and infiltration of vascular and kidney tissue with inflammatory cells leading to hypertension. Supplementation with dietary antioxidants including vitamins C, E, or B(6), thiols such as cysteine and lipoic acid, have been shown to lower blood pressure and plasma inflammatory cytokines in animal models and humans with essential hypertension. A well-balanced diet rich in antioxidants that includes vegetables, fruits, low fat dairy products, low salt, and includes whole grains, poultry, fish and nuts, lowers blood pressure and vascular inflammation. These antioxidants may achieve their antihypertensive and anti-inflammatory/immunomodulatory effects by reducing AGEs and improving insulin resistance and associated alterations. Dietary supplementation with antioxidants may be a beneficial, inexpensive, front-line alterative treatment modality for hypertension.
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Affiliation(s)
- Sudesh Vasdev
- Discipline of Medicine, Health Sciences Centre, Memorial University, St. John's, Newfoundland, Canada
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10
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Abstract
Hypertension is a leading cause of morbidity and mortality worldwide. Individuals with hypertension are at increased risk of stroke, heart disease and kidney failure. Although the etiology of essential hypertension has a genetic component, lifestyle factors such as diet play an important role. Reducing dietary salt is effective in lowering blood pressure in salt-sensitive individuals. Insulin resistance and altered glucose metabolism are common features of hypertension in humans and animal models, with or without salt sensitivity. Altered glucose metabolism leads to increased formation of advanced glycation end products. Insulin resistance is also linked to oxidative stress, and alterations in the nitric oxide pathway and renin angiotensin system. A diet rich in protein containing the semiessential amino acid, arginine, and arginine treatment, lowers blood pressure in humans and in animal models. This may be due to the ability of arginine to improve insulin resistance, decrease advanced glycation end products formation, increase nitric oxide, and decrease levels of angiotensin II and oxidative stress, with improved endothelial cell function and decreased peripheral vascular resistance. The Dietary Approaches to Stop Hypertension (DASH) study demonstrated that the DASH diet, rich in vegetables, fruits and low-fat dairy products; low in fat; and including whole grains, poultry, fish and nuts, lowered blood pressures even more than a typical North American diet with similar reduced sodium content. The DASH diet is rich in protein; the blood pressure-lowering effect of the DASH diet may be due to its higher arginine-containing protein, higher antioxidants and low salt content.
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Affiliation(s)
- Sudesh Vasdev
- Discipline of Medicine, Faculty of Medicine, Health Sciences Centre, Memorial University, St John's, Newfoundland
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Abstract
Hypertension is a leading cause of morbidity and mortality worldwide. Individuals with hypertension are at an increased risk for stroke, heart disease and kidney failure. Essential hypertension results from a combination of genetic and lifestyle factors. One such lifestyle factor is diet, and its role in the control of blood pressure has come under much scrutiny. Just as increased salt and sugar are known to elevate blood pressure, other dietary factors may have antihypertensive effects. Studies including the Optimal Macronutrient Intake to Prevent Heart Disease (OmniHeart) study, Multiple Risk Factor Intervention Trial (MRFIT), International Study of Salt and Blood Pressure (INTERSALT) and Dietary Approaches to Stop Hypertension (DASH) study have demonstrated an inverse relationship between dietary protein and blood pressure. One component of dietary protein that may partially account for its antihypertensive effect is the nonessential amino acid cysteine. Studies in hypertensive humans and animal models of hypertension have shown that N-acetylcysteine, a stable cysteine analogue, lowers blood pressure, which substantiates this idea. Cysteine may exert its antihypertensive effects directly or through its storage form, glutathione, by decreasing oxidative stress, improving insulin resistance and glucose metabolism, lowering advanced glycation end products, and modulating levels of nitric oxide and other vasoactive molecules. Therefore, adopting a balanced diet containing cysteine-rich proteins may be a beneficial lifestyle choice for individuals with hypertension. An example of such a diet is the DASH diet, which is low in salt and saturated fat; includes whole grains, poultry, fish and nuts; and is rich in vegetables, fruits and low-fat dairy products.
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Affiliation(s)
- Sudesh Vasdev
- Discipline of Medicine, Faculty of Medicine, Health Sciences Centre, Memorial University, St John's, Newfoundland
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Abstract
Altered glucose metabolism due to insulin resistance is a common feature of essential hypertension in humans and in animal models. Elevated endogenous aldehydes in genetic (spontaneously hypertensive rats) and acquired (fructose-induced hypertensive rats) models of essential hypertension may be due to increased production of the reactive aldehyde methylglyoxal, resulting from altered glucose metabolism. Excess methylglyoxal binds sulfhydryl groups of membrane proteins, altering calcium channels and increasing cytosolic free Ca(2+) and blood pressure. It has been demonstrated that methylglyoxal, when given in drinking water to Wistar-Kyoto rats, leads to an increase in kidney aldehyde conjugates, cytosolic free Ca(2+) concentration, decreased serum nitric oxide, renal vascular hyperplasia and hypertension. N-acetylcysteine (NAC) in the diet of these animals prevented hypertension and associated biochemical and morphological changes. NAC normalizes blood pressure by directly binding to excess methylglyoxal, thus normalizing Ca(2+) channels, cytosolic Ca(2+) and nitric oxide. NAC also leads to increased levels of tissue glutathione, a storage form of cysteine. Glutathione acts as a cofactor in the enzymatic catabolism of methylglyoxal. Cysteine and other antioxidants, such as vitamins B(6), C and E, and lipoic acid, prevented hypertension and associated biochemical and morphological changes in both genetic and acquired rat models of hypertension. The antihypertensive effect of dietary antioxidants may be due to an increase in tissue cysteine and glutathione, which improves glucose metabolism and decreases tissue methylglyoxal. A diet rich in these antioxidants may be effective in preventing and controlling hypertension in humans.
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Affiliation(s)
- Sudesh Vasdev
- Discipline of Medicine, Faculty of Medicine, Health Sciences Centre, Memorial University, St John's, Newfoundland and Labrador
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Putnam K, Shoemaker R, Yiannikouris F, Cassis LA. The renin-angiotensin system: a target of and contributor to dyslipidemias, altered glucose homeostasis, and hypertension of the metabolic syndrome. Am J Physiol Heart Circ Physiol 2012; 302:H1219-30. [PMID: 22227126 DOI: 10.1152/ajpheart.00796.2011] [Citation(s) in RCA: 159] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The renin-angiotensin system (RAS) is an important therapeutic target in the treatment of hypertension. Obesity has emerged as a primary contributor to essential hypertension in the United States and clusters with other metabolic disorders (hyperglycemia, hypertension, high triglycerides, low HDL cholesterol) defined within the metabolic syndrome. In addition to hypertension, RAS blockade may also serve as an effective treatment strategy to control impaired glucose and insulin tolerance and dyslipidemias in patients with the metabolic syndrome. Hyperglycemia, insulin resistance, and/or specific cholesterol metabolites have been demonstrated to activate components required for the synthesis [angiotensinogen, renin, angiotensin-converting enzyme (ACE)], degradation (ACE2), or responsiveness (angiotensin II type 1 receptors, Mas receptors) to angiotensin peptides in cell types (e.g., pancreatic islet cells, adipocytes, macrophages) that mediate specific disorders of the metabolic syndrome. An activated local RAS in these cell types may contribute to dysregulated function by promoting oxidative stress, apoptosis, and inflammation. This review will discuss data demonstrating the regulation of components of the RAS by cholesterol and its metabolites, glucose, and/or insulin in cell types implicated in disorders of the metabolic syndrome. In addition, we discuss data supporting a role for an activated local RAS in dyslipidemias and glucose intolerance/insulin resistance and the development of hypertension in the metabolic syndrome. Identification of an activated RAS as a common thread contributing to several disorders of the metabolic syndrome makes the use of angiotensin receptor blockers and ACE inhibitors an intriguing and novel option for multisymptom treatment.
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Affiliation(s)
- Kelly Putnam
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, 40536-0200, USA
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Dong JY, Qin LQ, Zhang Z, Zhao Y, Wang J, Arigoni F, Zhang W. Effect of oral L-arginine supplementation on blood pressure: a meta-analysis of randomized, double-blind, placebo-controlled trials. Am Heart J 2011; 162:959-65. [PMID: 22137067 DOI: 10.1016/j.ahj.2011.09.012] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 09/13/2011] [Indexed: 12/16/2022]
Abstract
BACKGROUND Previous studies suggest that L-arginine, an amino acid and a substrate of nitric oxide synthase, may have blood pressure (BP)-lowering effect. Because some studies were performed with limited number of patients with hypertension and therefore limited statistical power with sometimes inconsistent results, we aimed to examine the effect of oral L-arginine supplementation on BP by conducting a meta-analysis of randomized, double-blind, placebo-controlled trials. METHODS PubMed, Cochrane Central Register of Controlled Trials, and the ClinicalTrials.gov databases were searched through June 2011 to identify randomized, double-blind, placebo-controlled trials of oral L-arginine supplementation on BP in humans. We also reviewed reference lists of obtained articles. Either a fixed-effects or, in the presence of heterogeneity, a random-effects model was used to calculate the combined treatment effect. RESULTS We included 11 randomized, double-blind, placebo-controlled trials involving 387 participants with oral L-arginine intervention ranging from 4 to 24 g/d. Compared with placebo, L-arginine intervention significantly lowered systolic BP by 5.39 mm Hg (95% CI -8.54 to -2.25, P = .001) and diastolic BP by 2.66 mm Hg (95% CI -3.77 to -1.54, P < .001). Sensitivity analyses restricted to trials with a duration of 4 weeks or longer and to trials in which participants did not use antihypertensive medications yielded similar results. Meta-regression analysis suggested an inverse, though insignificant (P = .13), relation between baseline systolic BP and net change in systolic BP. CONCLUSIONS This meta-analysis provides further evidence that oral L-arginine supplementation significantly lowers both systolic and diastolic BP.
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Elovainio M, Merjonen P, Pulkki-Råback L, Kivimäki M, Jokela M, Mattson N, Koskinen T, Viikari JSA, Raitakari OT, Keltikangas-Järvinen L. Hostility, metabolic syndrome, inflammation and cardiac control in young adults: The Young Finns Study. Biol Psychol 2011; 87:234-40. [PMID: 21419189 DOI: 10.1016/j.biopsycho.2011.03.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 02/22/2011] [Accepted: 03/02/2011] [Indexed: 11/25/2022]
Abstract
We studied whether there is an association between hostility and cardiovascular heart disease (CHD) risk factors, such as the metabolic syndrome, systemic inflammation and autonomic cardiac control. Participants were 912 women and 712 men aged 15-30 when hostility was measured in 1992. Metabolic syndrome was assessed 9years later in 2001 using 3 definitions: the National Institute of Health Adult Treatment Panel III criteria (NCEP), the European Group for the Study of Insulin Resistance criteria (EGIR), and the International Diabetes Federation criteria (IDF). C-reactive protein (CRP) defined in 2001 was the marker of inflammation. Cardiac control indices were from EGC recording. In women, hostility predicted increased risk of metabolic syndrome (EGIR, and the IDF definitions, ORs = 1.34, 1.35, p < 0.05), and higher levels of inflammation (β = 0.09, p < 0.01). We concluded that hostility is associated with metabolic syndrome and systemic inflammation in women and these conditions may be factors linking hostility to CHD.
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Affiliation(s)
- Marko Elovainio
- Department of Behavioural Sciences, University of Helsinki, Finland.
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Ackerman Z, Oron-Herman M, Pappo O, Peleg E, Safadi R, Schmilovitz-Weiss H, Grozovski M. Hepatic effects of rosiglitazone in rats with the metabolic syndrome. Basic Clin Pharmacol Toxicol 2010; 107:663-8. [PMID: 20210788 DOI: 10.1111/j.1742-7843.2010.00553.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Rats given fructose-enriched diet develop many characteristics of the human metabolic syndrome and non-alcoholic fatty liver disease. In this study, we characterized the hepatic effects of rosiglitazone in fructose-enriched diet rats. Rats were randomly divided into three groups. One group was maintained on standard rat chow diet for 6 weeks, whereas the other two groups were given fructose-enriched diet for 6 weeks. Four weeks after the initiation of fructose-enriched diet, one of the fructose-enriched diet groups was also given rosiglitazone (10 mg/kg/day) for an additional 2 weeks. Rosiglitazone administration to the fructose-enriched diet rats was associated with decreases in the following parameters: blood pressure (-17%), plasma triglycerides (-62%), hepatic total lipids (-19%), hepatic triglycerides (-61%), hepatic malondialdehyde (-88%), glutathione reductase activity (-84%). An increase in adiponectin plasma levels (+329%), hepatic phospholipids (+46%), hepatic alpha-tocopherol concentrations (+24%) and hepatic paraoxonase activity (+68%) was observed. Rosiglitazone caused a decrease in hepatic macrovesicular steatosis score but no change in hepatic fibrosis. Administration of rosiglitazone, to rats with the metabolic syndrome has limited hepatic favourable effects: it improves hepatic lipid metabolism, decreases macrovesicular steatosis and improves some of the hepatic oxidative-anti-oxidative milieu but has no effect on hepatic fibrosis.
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Affiliation(s)
- Zvi Ackerman
- Department of Medicine, Mount Scopus Campus, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
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Abstract
While virtually absent in our diet a few hundred years ago, fructose has now become a major constituent of our modern diet. Our main sources of fructose are sucrose from beet or cane, high fructose corn syrup, fruits, and honey. Fructose has the same chemical formula as glucose (C(6)H(12)O(6)), but its metabolism differs markedly from that of glucose due to its almost complete hepatic extraction and rapid hepatic conversion into glucose, glycogen, lactate, and fat. Fructose was initially thought to be advisable for patients with diabetes due to its low glycemic index. However, chronically high consumption of fructose in rodents leads to hepatic and extrahepatic insulin resistance, obesity, type 2 diabetes mellitus, and high blood pressure. The evidence is less compelling in humans, but high fructose intake has indeed been shown to cause dyslipidemia and to impair hepatic insulin sensitivity. Hepatic de novo lipogenesis and lipotoxicity, oxidative stress, and hyperuricemia have all been proposed as mechanisms responsible for these adverse metabolic effects of fructose. Although there is compelling evidence that very high fructose intake can have deleterious metabolic effects in humans as in rodents, the role of fructose in the development of the current epidemic of metabolic disorders remains controversial. Epidemiological studies show growing evidence that consumption of sweetened beverages (containing either sucrose or a mixture of glucose and fructose) is associated with a high energy intake, increased body weight, and the occurrence of metabolic and cardiovascular disorders. There is, however, no unequivocal evidence that fructose intake at moderate doses is directly related with adverse metabolic effects. There has also been much concern that consumption of free fructose, as provided in high fructose corn syrup, may cause more adverse effects than consumption of fructose consumed with sucrose. There is, however, no direct evidence for more serious metabolic consequences of high fructose corn syrup versus sucrose consumption.
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Affiliation(s)
- Luc Tappy
- Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, CH-1005 Lausanne, Switzerland.
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Vasdev S, Gill VD, Randell E, Han Y, Gadag V. Fructose and moderately high dietary salt-induced hypertension: prevention by a combination of N-acetylcysteine and L-arginine. Mol Cell Biochem 2009; 337:9-16. [PMID: 19806432 DOI: 10.1007/s11010-009-0281-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Accepted: 09/16/2009] [Indexed: 02/05/2023]
Abstract
Diets containing 8% salt or 4% fructose (FR) cause insulin resistance and increase tissue methylglyoxal and advanced glycation end products (AGEs), platelet cytosolic-free calcium, and systolic blood pressure (SBP) in rats. In WKY rats, we have shown that moderately high salt, 4% NaCl (MHS) alone in diet does not cause hypertension, and when given along with 4% FR it does not have an additive effect. N-acetylcysteine (NAC) or L-arginine (ARG), treatment alone does not prevent hypertension in this model. The objectives of this study were to investigate the effect of NAC plus ARG in diet on SBP, platelet cytosolic-free calcium in a MHS + FR model, and to measure the plasma levels of methylglyoxal and the AGE, methylglyoxal-derived hydroimidazolone (MGH). At 7 weeks of age, WKY rats were divided into three groups: control group was given regular rat chow (0.7% NaCl) and water; MHS + FR group, diet containing 4% NaCl and 4% FR in drinking water; and MHS + FR + NAC + ARG group, MHS diet supplemented with 1.5% N-acetylcysteine (NAC) and 1.5% L-arginine (ARG), and 4% FR in drinking water, and followed for 6 weeks. NAC + ARG prevented the increase in platelet cytosolic-free calcium and SBP in MHS + FR treated rats. There was no difference in mean values of plasma methylglyoxal and MGH among the groups. In conclusion, NAC + ARG treatment is effective in preventing hypertension in a moderately high salt + FR-induced animal model. Plasma methylglyoxal and MGH may not represent tissue modification or, alternatively, other tissue AGEs, derived from methylglyoxal or other aldehydes, may be involved in hypertension in this model.
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Affiliation(s)
- Sudesh Vasdev
- Department of Medicine, Health Sciences Centre, Memorial University, St. John's, NL, Canada.
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Tran LT, Yuen VG, McNeill JH. The fructose-fed rat: a review on the mechanisms of fructose-induced insulin resistance and hypertension. Mol Cell Biochem 2009; 332:145-59. [PMID: 19536638 DOI: 10.1007/s11010-009-0184-4] [Citation(s) in RCA: 258] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 06/09/2009] [Indexed: 02/07/2023]
Abstract
The metabolic syndrome is an important public health concern that predisposes individuals to the development of cardiovascular disease and/or Type 2 diabetes. The fructose-fed rat is an animal model of acquired systolic hypertension that displays numerous features of the metabolic syndrome. This animal model is used to study the relationship between insulin resistance/compensatory hyperinsulinemia and the development of hypertension. Several mechanisms have been proposed to mediate the link between insulin resistance and hypertension. In this review, we have addressed the role of sympathetic nervous system overactivation, increased production of vasoconstrictors, such as endothelin-1 and angiotensin II, and prostanoids in the development of hypertension in fructose-fed rats. The roles of nitric oxide, impaired endothelium-dependent relaxation and sex hormones in the pathogenesis of the fructose-fed induced hypertensive rats have also been highlighted. More recently, increased formation of reactive oxygen species and elevated levels of uric acid have been reported to contribute to fructose-induced hypertension.
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Affiliation(s)
- Linda T Tran
- Division of Pharmacology & Toxicology, Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC, V6T 1Z3, Canada
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Nagai Y, Ichihara A, Nakano D, Kimura S, Pelisch N, Fujisawa Y, Hitomi H, Hosomi N, Kiyomoto H, Kohno M, Ito H, Nishiyama A. Possible contribution of the non-proteolytic activation of prorenin to the development of insulin resistance in fructose-fed rats. Exp Physiol 2009; 94:1016-23. [PMID: 19502292 DOI: 10.1113/expphysiol.2009.048108] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Recent studies have shown that blocking non-proteolytically activated prorenin with a decoy peptide for the handle region of the prorenin prosegment (HRP) inhibits the development of microvascular complications in diabetic animals. In the present study, we investigated whether non-proteolytic activation of prorenin contributes to the development of fructose-induced insulin resistance. Rats were fed a standard diet (n = 10), a 60% high fructose diet (n = 16), or a high fructose diet + HRP (0.1 mg kg(-1) day(-1), n = 16) for 10 weeks. Fructose-fed rats showed higher systolic blood pressure (SBP), fasting plasma triglycerides, total cholesterol and insulin levels; which, except for SBP, were suppressed by HRP. The responses of plasma glucose and insulin levels to oral glucose loading were significantly greater in fructose-fed rats than in standard diet-fed rats. The HRP normalized the enhanced responses of plasma glucose and insulin levels that were observed in fructose-fed rats. Moreover, HRP suppressed the enhanced prorenin activation and angiotensin II formation in the soleus muscle of fructose-fed rats. These data suggest that local angiotensin II generation in skeletal muscle, induced by non-proteolytic activation of prorenin, contributes to the development of insulin resistance induced by a high fructose diet.
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Affiliation(s)
- Yukiko Nagai
- Life Sciences Research Center, Kagawa University, Miki, Kita, Kagawa 761-0793, Japan
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Manco M, Giordano U, Turchetta A, Fruhwirth R, Ancinelli M, Marcellini M, Nobili V. Insulin resistance and exercise capacity in male children and adolescents with non-alcholic fatty liver disease. Acta Diabetol 2009; 46:97-104. [PMID: 18839055 DOI: 10.1007/s00592-008-0063-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Accepted: 09/15/2008] [Indexed: 12/16/2022]
Abstract
Insulin resistance (IR) and obesity may be associated with impaired response to physical exercise. We aimed at assessing physical capacity in obese children with biopsy proven non-alcoholic fatty liver disease (NAFLD) as compared to normal weight and obese children without fatty liver disease. All male subjects, 20 NAFLD and 31 control individuals (20 obese, without NAFLD and 11 normal weight children) took part in the study. We evaluated changes in cardiovascular parameters during a bicycle-ergometer exercise test (James' test). Duration, power of exercise, heart rate (HR), blood pressure (BP), pulse pressure, cardiac output ((I)CO) and total peripheral vascular resistance indexed for height ((I)TPVR) were recorded at rest ((r)) and peak ((p)) exercise. The homeostatic model assessment was used to determine insulin resistance (HOMA-IR) and beta-cell action (HOMA-beta cell). In NAFLD and obese subjects, fasting leptin, insulin secretion, insulinogenic index (IGI), muscle insulin sensitivity (MISI) and hepatic insulin resistance index (HIRI) were assayed. Children with NAFLD were the most insulin-resistant (P = 0.001), and showed higher HIRI than obese controls (P = 0.05). At rest, they had the lowest values of SBP(r) (P = 0.001 vs. controls and P < or = 0.05 vs. obese controls); during the test, the highest values of (I)CO(p) (P = 0.005), Delta(I)CO (P = 0.003) and DeltaTRVP(p) (P < or = 0.0001). NAFLD and obese controls both had impaired DeltaHR(p) (P < or = 0.0001). However, obese controls were not able to reduce peripheral resistance during the test. HOMA-IR explained 28% of variance in Delta(I)CO of the whole sample, (P < or = 0.0001). In obese children with or without NAFLD, increased IR and body weight may induce cardiovascular compensatory changes in response to physical exercise with fairly different pathogenetic mechanisms, which are likely to be dependent on the different degree of IR.
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Affiliation(s)
- Melania Manco
- Scientific Directorate, Bambino Gesù Children's Hospital and Research Institute, S. Onofrio 4 square, 00165, Rome, Italy.
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Tran LT, MacLeod KM, McNeill JH. Endothelin-1 modulates angiotensin II in the development of hypertension in fructose-fed rats. Mol Cell Biochem 2009; 325:89-97. [PMID: 19139972 DOI: 10.1007/s11010-008-0023-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Accepted: 12/30/2008] [Indexed: 02/07/2023]
Abstract
Two of the most potent vasoconstrictors, endothelin-1 (ET-1) and angiotensin II (Ang II), are upregulated in fructose hypertensive rats. It is unknown whether an interrelationship exists between these peptides that may contribute to the development of fructose-induced hypertension. The objective of this study was to investigate the existence of an interaction between the endothelin and renin angiotensin systems that may play a role in the development of fructose-induced hypertension. High fructose feeding and treatment with either bosentan, a dual endothelin receptor antagonist, or with L-158,809, an angiotensin type 1 receptor antagonist, were initiated simultaneously in male Wistar rats. Systolic blood pressure, fasted plasma parameters, insulin sensitivity, plasma Ang II, and vascular ET-1-immunoreactivity were determined following 6 weeks of high fructose feeding. Rats fed with a high fructose diet exhibited insulin resistance, hyperinsulinemia, hypertriglyceridemia, hypertension, and elevated plasma Ang II. Treatment with either bosentan or L-158,809 significantly attenuated the rise in blood pressure with no effect on insulin levels or insulin sensitivity in fructose-fed rats. Bosentan treatment significantly reduced plasma Ang II levels, while L-158,809 treatment significantly increased vascular ET-1-immunoreactivity in fructose-fed rats. Thus, treatment with the endothelin receptor antagonist prevented the development of fructose-induced hypertension and decreased plasma Ang II levels. These data suggest that ET-1 contributes to the development of fructose-induced hypertension through modulation of Ang II levels.
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Affiliation(s)
- L T Tran
- Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC, V6T 1Z3, Canada
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Perinatal taurine depletion increases susceptibility to adult sugar-induced hypertension in rats. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 643:123-33. [PMID: 19239143 PMCID: PMC2706705 DOI: 10.1007/978-0-387-75681-3_13] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
This study tests the hypothesis that perinatal taurine depletion produces autonomic nervous system dysregulation and increases arterial pressure in young male rats maintained on a high sugar diet. Sprague-Dawley dams were either taurine depleted (beta-alanine 3% in water) or left untreated from conception to weaning. Their male offspring were fed normal rat chow with or without 5% glucose. At 7-8 weeks of age, the male offspring were either tested in a conscious, unrestrained state or after anesthetia. Body weight was slightly lower in the taurine-depleted rats although their heart or kidneys to body weight ratios were similar. Plasma potassium, blood urea nitrogen, plasma creatinine, hematocrit, fasting blood glucose concentrations and glucose tolerance were all similar. In the taurine-depleted, high glucose group, mean arterial pressure and sympathetic nervous system activity were increased while baroreflex function was impaired. These findings suggest that in this model perinatal taurine depletion causes autonomic nervous system dysfunction that may contribute to dietary high sugar-induced hypertension.
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Chen CY, Hwu CM, Lin MW, Tsai CH, Yeh HI. High triglyceride level is associated with severe coronary artery disease in hypertensive subjects. SCAND CARDIOVASC J 2008; 42:146-52. [PMID: 18365898 DOI: 10.1080/14017430701840325] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND The contribution of triglycerides (TG) to the extent of coronary artery disease (CAD) in hypertensive patients remained unclear. METHODS Consecutive 821 (aged 64.5+/-11.5 years, 482 males) hypertensive patients undergoing coronary angiography were included. The relationship of TG levels (<150 vs. > or =150 mg/dl) to the extent of CAD in all patients was examined by multiple logistic regression, adjusting for other CAD risk factors. In the lipid group, low levels of HDL were also adjusted. RESULTS Higher levels of TG were found in subjects with severe CAD compared to those with no or minimal CAD. The adjusted odds ratios for high levels of TG in the severe CAD subgroup versus the no or minimal CAD subgroup were 5.20 (95% CI, 3.13 to 8.63) in all patients and 7.51 (95% CI, 3.19 to 17.65) in the lipid group. CONCLUSIONS High levels of TG are strong clinical markers of greater extent of CAD in hypertensive subjects undergoing coronary angiography. The results may have clinical relevance for physicians in therapeutic decision making.
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Affiliation(s)
- Chun-Yen Chen
- Cardiovascular Division, Department of Internal Medicine, Mackay Memorial Hospital, Taipei, Taiwan
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Angiotensin receptor blockers improve insulin signaling and prevent microvascular rarefaction in the skeletal muscle of spontaneously hypertensive rats. J Hypertens 2008; 26:1595-601. [DOI: 10.1097/hjh.0b013e328304b060] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Abstract
Recently oxidative stress has been proposed as the cause of hypertension. An imbalance in superoxide and nitric oxide production may account for reduced vasodilation, which in turn can favor the development of hypertension. In vitro and in human studies support this hypothesis. The supplementation of antioxidants, particularly in the form of fresh fruit and vegetables, reduces blood pressure, supporting a role for free radicals in hypertension.
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Affiliation(s)
- Antonio Ceriello
- Centre of Excellence in Diabetes and Endocrinology, University Hospital of Coventry and Warwickshire, Warwick Medical School, University of Warwick, Coventry, UK.
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Almgren T, Wilhelmsen L, Samuelsson O, Himmelmann A, Rosengren A, Andersson OK. Diabetes in treated hypertension is common and carries a high cardiovascular risk: results from a 28-year follow-up. J Hypertens 2007; 25:1311-7. [PMID: 17563546 DOI: 10.1097/hjh.0b013e328122dd58] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE The objective of this study was to analyse predictive factors for development of type 2 diabetes during life-long therapy for hypertension and the alleged additional cardiovascular risk this constitutes. METHODS The study group (n = 754) comprised the hypertensive subgroup of a randomized population sample of 7500 men, aged 47-54 years, screened for cardiovascular risk factors and followed for 25-28 years. The patients were treated with thiazide diuretics and beta-adrenergic blocking drugs with the addition of hydralazin during the first decade. Calcium antagonists were substituted for hydralazin and, if needed, angiotensin-converting enzyme inhibitors were added when these drugs became available. RESULTS A total of 148 (20.4%) treated hypertensive patients developed diabetes during 25 years, and in multivariate Cox regression analysis body mass index, serum triglycerides and treatment with beta-blockers were positively related with this complication. New-onset diabetes implied a significantly increased risk for stroke [hazard ratio (HR): 1.67; 95% confidence interval (95% CI): 1.1-2.6; P < 0.05], myocardial infarction (OR: 1.66; 95% CI: 1.1-2.5; P < 0.05) and mortality (OR: 1.42; 95% CI: 1.1-1.9; P < 0.05). The greatest risk for stroke was new-onset diabetes, followed by smoking (OR: 1.46; 95% CI: 1-2.2; P = 0.07) and the greatest risk for myocardial infarction was new-onset diabetes, followed by smoking (HR: 1.64; 95% CI: 1.1-2.4; P < 0.01). The greatest risk for mortality was smoking (HR: 1.73; 95% CI: 1.3-2.2; P < 0.005). Achieved systolic and diastolic blood pressure were not predictive of cardiovascular complications or death. The mean observation time from onset of diabetes mellitus to a first stroke was 9.1 years and to a first myocardial infarction 9.3 years. CONCLUSION Diabetes in treated hypertensive patients is alarmingly common and carries a high risk for cardiovascular complications and mortality.
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Affiliation(s)
- Torbjörn Almgren
- Department of Internal Medicine, Sahlgrenska University Hospital, Goteborg, Sweden
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Kannel WB. Cardiovascular disease preventive measures for the older patient: an epidemiologic perspective. ACTA ACUST UNITED AC 2007; 15:382-8. [PMID: 17086034 DOI: 10.1111/j.1076-7460.2006.04397.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- William B Kannel
- The Framingham Heart Study/Boston University School of Medicine, 73 Mount Wayte Avenue, Framingham, MA 01702, USA.
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Vasdev S, Gill V, Parai S, Gadag V. Fructose-induced hypertension in Wistar–Kyoto rats: interaction with moderately high dietary saltThis paper is one of a selection of papers published in this Special Issue, entitled The Cellular and Molecular Basis of Cardiovascular Dysfunction, Dhalla 70th Birthday Tribute. Can J Physiol Pharmacol 2007; 85:413-21. [PMID: 17612650 DOI: 10.1139/y06-080] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the effects of 4% fructose plus moderately high salt (MHS) (4% NaCl) treatment on tissue aldehyde conjugates, platelet cytosolic free calcium ([Ca2+]i), renal morphology, and systolic blood pressure (SBP) in Wistar–Kyoto rats, and whether these effects were reversible (R) after withdrawal of treatment. At age 7 weeks, rats were divided into 4 groups: NS group, given normal salt (NS) diet (0.7% NaCl) for 18 weeks; NS+F(R) group, NS diet and fructose in water for 14 weeks, then 4 weeks fructose withdrawal; MHS+F group, NS diet and fructose for 6 weeks, then MHS diet and fructose for 12 weeks; and MHS+F(R) group, NS diet and fructose for 6 weeks, then MHS diet and fructose for 8 weeks, then MHS and fructose withdrawal for 4 weeks. SBP in the NS+F(R) group increased during fructose treatment, but normalized within 1 week of withdrawal. Tissue aldehyde conjugates and platelet [Ca2+]i were normal at completion. Adverse renal vascular changes did not reverse to normal and were similar to those of the salt plus fructose-treated groups. This may have implications for future development of hypertension. MHS did not cause any additional increase in SBP or associated tissue alterations when added to fructose treatment. However, the SBP and tissue changes persisted even after discontinuation of treatment. The fructose and salt combination may result in long-lasting vascular alterations leading to hypertension.
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Affiliation(s)
- Sudesh Vasdev
- Department of Medicine and Laboratory Medicine Health Sciences Centre, Memorial University of Newfoundland, St. John's, NL A1B 3V6, Canada.
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Coronary Risk Factors: An Overview. CARDIOVASCULAR MEDICINE 2007. [DOI: 10.1007/978-1-84628-715-2_128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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32
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Lloyd-Jones DM, Levy D. Epidemiology of Hypertension. Hypertension 2007. [DOI: 10.1016/b978-1-4160-3053-9.50007-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Yamaguchi K, Ura N, Murakami H, Togashi N, Hyakukoku M, Higashiura K, Shimamoto K. Olmesartan ameliorates insulin sensitivity by modulating tumor necrosis factor-alpha and cyclic AMP in skeletal muscle. Hypertens Res 2006; 28:773-8. [PMID: 16419651 DOI: 10.1291/hypres.28.773] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We have reported that tumor necrosis factor (TNF)-alpha in skeletal muscle is one of the determinants of insulin resistance and that the renin-angiotensin system may be related to the regulation of TNF-a in skeletal muscle. Recent studies have suggested the involvement of cyclic adenosine monophosphate (cAMP) in the regulation of TNF-a in vascular smooth muscle cells or monocytes. The aim of this study was to determine the relationship between cAMP and TNF-a in skeletal muscle in connection with the renin-angiotensin system. Six-week-old male Sprague-Dawley rats were fed either normal rat chow or fructose-rich chow for 6 weeks. For the last 2 weeks of a 6-week period, the rats were treated with a vehicle or with an angiotensin II type 1 receptor antagonist (olmesartan medoxomil, 0.1 mg/kg/day). TNF-alpha levels in the soleus muscle were significantly higher and cAMP levels in the soleus muscle were significantly lower in fructose-fed rats than in control rats. Olmesartan increased cAMP and reduced TNF-a simultaneously in fructose-fed rats. There was a significant negative correlation between levels of cAMP and TNF-alpha. Moreover, a cAMP analogue reduced TNF-a levels in the soleus muscle. These results indicate that the increase in TNF-alpha via suppression of cAMP may affect the induction of insulin resistance. In addition, the facts that olmesartan increased cAMP and decreased TNF-alpha suggest that a part of the TNF-alpha regulation by angiotensin II might consist of modulation of cAMP through Gi protein activation in skeletal muscle.
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Affiliation(s)
- Koichi Yamaguchi
- Second Department of Internal Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
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Katovich MJ, Grobe JL, Huentelman M, Raizada MK. Angiotensin‐converting enzyme 2 as a novel target for gene therapy for hypertension. Exp Physiol 2005; 90:299-305. [PMID: 15640278 DOI: 10.1113/expphysiol.2004.028522] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Less than one-third of patients with hypertension have their blood pressures (BP) controlled with current traditional therapeutic approaches for the treatment and control of hypertension. Pharmacological approaches may have reached a plateau in their effectiveness and thus newer innovative strategies need to be studied not only to increase the number of patients that can achieve BP control, but also to find a way to cure, not just manage, the disease. Continuous advances in gene delivery systems coupled with the completion of the Human Genome Project, now make it possible to investigate genetic means for the treatment and possible cure for hypertension. The renin-angiotensin system (RAS) has long been known to regulate BP, and salt and water metabolism. This system is unique in having both a peripheral circulating system and a tissue-based system. Each of these components have been ascribed a variety of physiological effects that have been associated with not only an increase in BP, but also in a variety of the pathophysiological manifestations associated with hypertension, such as cardiac hypertrophy and kidney dysfunction. We and others have used an antisense gene therapy approach, targeting the classical components of the RAS, to effectively attenuate the development of hypertension and related cardiovascular pathophysiologies in numerous experimental models of hypertension. Recently other components of the RAS have been elucidated and some of these components may be potential targets in a gene therapy approach. This article will focus on angiotensin-converting enzyme 2 (ACE2) as a new, potential target of gene therapy for hypertensive disorders.
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Affiliation(s)
- Michael J Katovich
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, PO Box 100487, Gainesville, FL 32610-0487, USA.
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Ackerman Z, Oron-Herman M, Grozovski M, Rosenthal T, Pappo O, Link G, Sela BA. Fructose-induced fatty liver disease: hepatic effects of blood pressure and plasma triglyceride reduction. Hypertension 2005; 45:1012-8. [PMID: 15824194 DOI: 10.1161/01.hyp.0000164570.20420.67] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The most known risk factor for nonalcoholic fatty liver disease (NAFLD) is the metabolic syndrome. In this study, we characterized changes in liver pathology, hepatic lipid composition, and hepatic iron concentration (HIC) occurring in rats given fructose-enriched diet (FED), with and without therapeutic maneuvers to reduce blood pressure and plasma triglycerides. Rats were given FED or standard rat chow for 5 weeks. Rats on FED were divided into 4 groups: receiving amlodipine (15 mg/kg per day), captopril (90 mg/kg per day), bezafibrate (10 mg/kg per day) in the last 2 weeks, or a control group that received FED only. FED rats had hepatic macrovesicular and microvesicular fat deposits develop, with increase in hepatic triglycerides (+198%) and hepatic cholesterol (+89%), but a decrease in hepatic phospholipids (-36%), hypertriglyceridemia (+223%), and hypertension (+15%), without increase in HIC. Amlodipine reduced blood pressure (-18%), plasma triglycerides (-12%), but there was no change in hepatic triglycerides and phospholipids concentrations. Captopril reduced blood pressure (-24%), plasma triglycerides (-36%), hepatic triglycerides (-51%), and hepatic macrovesicular fat (-51%), but increased HIC (+23%), with a borderline increase in hepatic fibrosis. Bezafibrate reduced plasma triglycerides (-49%), hepatic triglycerides (-78%), hepatic macrovesicular fat (-90%), and blood pressure (-11%). We conclude that FED rats can be a suitable model for human NAFLD. Drugs administered to treat various aspects of the metabolic syndrome could have hepatic effects. An increase in HIC in rats with NAFLD could be associated with increased hepatic fibrosis.
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Affiliation(s)
- Zvi Ackerman
- Hebrew University Hadassah Medical Center, Jerusalem, Israel.
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36
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Kannel WB. Coronary Atherosclerotic Sequelae of Hypertension. Hypertension 2005. [DOI: 10.1016/b978-0-7216-0258-5.50113-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Abstract
Essential hypertension in humans may develop through a combination of genetic and environmental factors. Diet has long been under investigation as a potential effector of blood pressure. A diet high in sucrose or fructose can give rise to hyperlipidemia, insulin resistance and hypertension. Insulin resistance, glucose intolerance and oxidative stress are common features of hypertension. If glucose metabolism through the glycolytic pathway is impaired, as in insulin resistance, there will be a build-up of glyceraldehyde, glyceraldehyde-3-phosphate and dihydroxyacetone phosphate with further metabolism to methylglyoxal, a highly reactive ketoaldehyde. Excess aldehydes can bind sulfhydryl groups of membrane proteins, altering membrane calcium channels, increasing cytosolic free calcium, peripheral vascular resistance and blood pressure. The presence of reactive aldehydes can also lead to oxidative stress. Dietary management through lower sucrose or fructose intake and increased consumption of vitamins improves glucose metabolism, lowers tissue aldehydes, increases anti-oxidant capacity and may also prevent hypertension.
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Affiliation(s)
- Sudesh Vasdev
- Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.
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38
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Vasdev S, Gill V, Longerich L, Parai S, Gadag V. Salt-induced hypertension in WKY rats: prevention by alpha-lipoic acid supplementation. Mol Cell Biochem 2004; 254:319-26. [PMID: 14674712 DOI: 10.1023/a:1027354005498] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
There is strong evidence that points to excess dietary salt as a major factor contributing to the development of hypertension. Salt sensitivity is associated with glucose intolerance and insulin resistance in both animal models and humans. In insulin resistance, impaired glucose metabolism leads to elevated endogenous aldehydes which bind to vascular calcium channels, increasing cytosolic [Ca2+]i and blood pressure. In an insulin resistant animal model of hypertension, spontaneously hypertensive rats (SHRs), dietary supplementation with lipoic acid lowers tissue aldehydes and plasma insulin levels and normalizes blood pressure. The objective of this study is to examine the effects of a high salt diet on tissue aldehydes, cytosolic [Ca2+]i and blood pressure in WKY rats and to investigate whether dietary supplementation with lipoic acid can prevent a salt induced increase in blood pressure. Starting at 7 weeks of age, WKY rats were divided into three groups of six animals each and treated for 10 weeks with diets as follows: WKY-normal salt (0.7% NaCl); WKY-high salt (8% NaCl); WKY-high salt + lipoic acid (8% NaCl diet + lipoic acid 500 mg/Kg feed). At completion, animals in the high salt group had elevated systolic blood pressure, platelet [Ca2+]i, and tissue aldehyde conjugates compared with the normal salt group and showed smooth muscle cell hyperplasia in the small arteries and arterioles of the kidneys. Dietary alpha-lipoic acid supplementation in high salt-treated WKY rats normalized systolic blood pressure and cytosolic [Ca2+]i and aldehydes in liver and aorta. Kidney aldehydes and renal vascular changes were attenuated, but not normalized.
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Affiliation(s)
- Sudesh Vasdev
- Department of Medicine and Laboratory Medicine, Health Sciences Centre, Memorial University of Newfoundland, St. John's Newfoundland, Canada.
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39
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Jang YJ, Ryu HJ, Choi YO, Lee JG, Kim C, Leem CH, Park CS. Effects of an intracellular Ca(2+) chelator on insulin resistance and hypertension in high-fat-fed rats and spontaneously hypertensive rats. Metabolism 2004; 53:269-72. [PMID: 15015134 DOI: 10.1016/j.metabol.2003.10.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We explored the possibility that a sustained elevation of intracellular Ca(2+) concentration ([Ca(2+)](i)) may be a cellular abnormality common to both insulin resistance and hypertension. In high-fat diet (HFD) fed rats, the steady-state glucose infusion rate (GIR) during the euglycemic hyperinsulinemic clamp was reduced by 40% (P <.05) and mean arterial pressure (MAP) was elevated by 20 mm Hg (P <.01) in comparison to the normal chow-fed rats. Intravenous injection of 5,5'-dimethyl derivative of bis(o-aminophenoxy)ethane-N,N,N',N' tetraacetic acetoxymethyl ester (dimethyl-BAPTA/AM), an effective intracellular Ca(2+) chelator, 90 minutes before the clamp not only restored about 50% of the reduced GIR, but also normalized MAP in the HFD rats. The chelator injection also significantly increased GIR by 25% (P <.01) and reduced MAP about 30 mm Hg (P <.01) in the spontaneously hypertensive rats (SHR). In addition, we have recently shown in the HFD rats that an injection of dimethyl-BAPTA/AM normalizes elevated [Ca(2+)](i) in adipocytes. These results together demonstrate that lowering [Ca(2+)](i) simultaneously ameliorates both insulin resistance and hypertension and provide presumptive evidence that sustained high levels of [Ca(2+)](i) may play a common pathophysiologic role in these 2 diseases.
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Affiliation(s)
- Y J Jang
- Department of Physiology, University of Ulsan College of Medicine, Seoul, Korea
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40
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Pravenec M, Kazdová L, Landa V, Zidek V, Mlejnek P, Jansa P, Wang J, Qi N, Kurtz TW. Transgenic and recombinant resistin impair skeletal muscle glucose metabolism in the spontaneously hypertensive rat. J Biol Chem 2003; 278:45209-15. [PMID: 12944409 DOI: 10.1074/jbc.m304869200] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Increased serum levels of resistin, a molecule secreted by fat cells, have been proposed as a possible mechanistic link between obesity and insulin resistance. To further investigate the effects of resistin on glucose metabolism, we derived a novel transgenic strain of spontaneously hypertensive rats expressing the mouse resistin gene under the control of the fat-specific aP2 promoter and also performed in vitro studies of the effects of recombinant resistin on glucose metabolism in isolated skeletal muscle. Expression of the resistin transgene was detected by Northern blot analysis in adipose tissue and by real-time PCR in skeletal muscle and was associated with increased serum fatty acids and muscle triglycerides, impaired skeletal muscle glucose metabolism, and glucose intolerance in the absence of any changes in serum resistin concentrations. In skeletal muscle isolated from non-transgenic spontaneously hypertensive rats, in vitro incubation with recombinant resistin significantly inhibited insulin-stimulated glycogenesis and reduced glucose oxidation. These findings raise the possibility that autocrine effects of resistin in adipocytes, leading to release of other prodiabetic effector molecules from fat and/or paracrine actions of resistin secreted by adipocytes embedded within skeletal muscle, may contribute to the pathogenesis of disordered skeletal muscle glucose metabolism and impaired glucose tolerance.
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MESH Headings
- Adipocytes/metabolism
- Animals
- Animals, Genetically Modified
- Blotting, Northern
- Blotting, Western
- Body Weight
- Glucose/metabolism
- Glucose Tolerance Test
- Glycogen/metabolism
- Hormones, Ectopic/blood
- Hormones, Ectopic/genetics
- Hormones, Ectopic/metabolism
- Intercellular Signaling Peptides and Proteins
- Lipid Metabolism
- Mice
- Mice, Inbred BALB C
- Models, Biological
- Muscle, Skeletal/metabolism
- Nerve Growth Factor
- Oxygen/metabolism
- Phenotype
- Promoter Regions, Genetic
- Proteins
- Rats
- Rats, Inbred SHR
- Recombinant Proteins/metabolism
- Resistin
- Reverse Transcriptase Polymerase Chain Reaction
- Time Factors
- Transgenes
- Triglycerides/metabolism
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Affiliation(s)
- Michal Pravenec
- Institute of Physiology, Czech Academy of Sciences and the Center for Integrated Genomics, Prague 14220, Czech Republic.
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41
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Yamaguchi K, Higashiura K, Ura N, Murakami H, Hyakukoku M, Furuhashi M, Shimamoto K. The effect of tumor necrosis factor-alpha on tissue specificity and selectivity to insulin signaling. Hypertens Res 2003; 26:389-96. [PMID: 12887130 DOI: 10.1291/hypres.26.389] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Recent studies have indicated that tumor necrosis factor (TNF)-alpha plays a significant role in insulin resistance. It has been proposed that selective impairment of insulin signaling in glucose metabolism is related to the development of atherosclerosis, although the mechanisms are not clear. The aim of this study was to elucidate the effect of TNF-alpha on tissue specificity and selectivity to insulin signaling. L6 myotubes and rat aortic vascular smooth muscle cells (VSMC) were cultured. Cells were stimulated with insulin pretreated with or without TNF-alpha. The protein extracts were used for electrophoresis and immunoblotting studies to examine phosphorylation of insulin receptor (IR)-beta, insulin receptor substrate (IRS)-1 and extracellular signal-regulated kinase (ERK). IR-beta phosphorylation was not affected by TNF-alpha in L6 or in VSMC. TNF-alpha significantly (p<0.05) inhibited IRS-1 phosphorylation by insulin but had no effect on ERK in L6. TNF-alpha had no effect on either IRS-1 phosphorylation or ERK in VSMC. Insulin induced ERK phosphorylation in a dose-dependent manner in VSMC. These results suggests that TNF-alpha plays a significant role in the tissue specificity and signal selectivity of insulin resistance. The pathway related to glucose metabolism is selectively impaired by TNF-alpha in skeletal muscle, and this impairment may induce compensatory hyperinsulinemia, which in turn would stimulate the pathway related to the cell proliferation in vascular tissues and possibly enhance the progression of atherosclerosis.
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Affiliation(s)
- Koichi Yamaguchi
- Second Department of Internal Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan.
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42
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Valensi P, Doaré L, Perret G, Germack R, Pariès J, Mesangeau D. Cardiovascular vagosympathetic activity in rats with ventromedial hypothalamic obesity. OBESITY RESEARCH 2003; 11:54-64. [PMID: 12529486 DOI: 10.1038/oby.2003.10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Rats with ventromedial hypothalamic lesion (VMH) are massively obese with endogenous hyperinsulinemia, insulin resistance, low sympathetic activity, and high parasympathetic activity, which are likely to induce hypertension. The goal was to follow in this model the long-term hemodynamic changes and to investigate the role of autonomic nervous system and insulin resistance in these changes. RESEARCH METHODS AND PROCEDURES Heart rate and blood pressure were monitored for 12 weeks after operation using a telemetric system in VMH and sham rats. Plasma catecholamines and heart beta-adrenoceptors were measured. Glucose tolerance was studied after an intravenous glucose injection and insulin sensitivity during a euglycemic hyperinsulinemic clamp test. RESULTS A marked bradycardia and only a mild increase in blood pressure occurred in VMH rats compared with sham animals. Response to autonomic-acting drugs showed an increase in heart vagal tone and responsiveness to a beta-agonist drug. Plasma catecholamine levels were markedly increased, and the density and affinity of heart beta-adrenoceptors were similar in VMH, sham, and control rats. Muscle glucose use was reduced by 1 week after operation in VMH animals. DISCUSSION These results show the following in this model of massively obese rats with sympathetic impairment: 1). adrenal medulla secretion is increased, probably as a result of hyperinsulinemia and increased vagal activity; 2). cardiac responsiveness to beta-agonist stimulation is increased; and 3). despite these changes and suspected resistance to the vasodilative effect of insulin, blood pressure does not increase. We conclude that high vagal activity may be protective against hypertension associated with obesity.
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Affiliation(s)
- Paul Valensi
- Laboratory of Nutrition and Metabolic Diseases, Paris-Nord University, Bondy, France.
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43
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Galipeau D, Verma S, McNeill JH. Female rats are protected against fructose-induced changes in metabolism and blood pressure. Am J Physiol Heart Circ Physiol 2002; 283:H2478-84. [PMID: 12427595 DOI: 10.1152/ajpheart.00243.2002] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objective of this study was to determine whether the effects of a fructose diet, which causes hyperinsulinemia, insulin resistance, and hypertension in male rats, are dependent on sex. Blood pressure was measured via the tail-cuff method, and oral glucose tolerance tests were performed to assess insulin sensitivity. Blood pressure in female rats did not differ between fructose-fed and control rats at any time point (126 +/- 5 and 125 +/- 3 mmHg at week 9 for fructose-fed and control rats, respectively) nor was there a difference in any metabolic parameter measured. Furthermore, the vascular insulin resistance that is present in male fructose-fed rats was not observed. After ovariectomy, fructose caused a significant change in systolic blood pressure from baseline compared with fructose-fed ovary-intact rats (change of 21 +/- 5 vs. -2 +/- 4 mmHg). The results demonstrate that females do not develop hypertension or hyperinsulinemia upon fructose feeding except after ovariectomy, suggesting that female sex hormones may confer protection against the effects of a fructose diet.
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Affiliation(s)
- Denise Galipeau
- Division of Pharmacology and Toxicology, University of British Columbia, Vancouver, Canada V6T 1Z3
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44
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45
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Imazu M, Sumii K, Yamamoto H, Toyofuku M, Okimoto T, Gomyo Y, Ueda H, Hayashi Y, Kohno N. Hyperinsulinemia as a risk factor for restenosis after coronary balloon angioplasty. JAPANESE CIRCULATION JOURNAL 2001; 65:947-52. [PMID: 11716244 DOI: 10.1253/jcj.65.947] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The present study evaluated whether hyperinsulinemia is a predictor of restenosis after coronary balloon angioplasty in 69 patients who underwent elective coronary balloon angioplasty; patients were excluded if they were known diabetics being treated with insulin. Quantitative coronary angiography was performed before and after angioplasty and at follow-up. Restenosis was defined as the presence of > or = 50% stenosis at follow-up. Plasma insulin responses before, 30, 60, and 120 min after 75 g glucose load (OGTT) were measured. Plasma insulin levels were higher in patients with restenosis than in patients without restenosis. Minimal lumen diameter at follow-up was smaller, and percent diameter stenosis at follow-up was higher and late loss was greater in the highest sum of insulin levels during OGTT (sigma insulin) quartile (0.95+/-0.15 vs 1.47+/-0.09 mm, p=0.005; 66.3+/-5.8 vs 40.5+/-3.3%, p=0.0003; 0.90+/-0.15 vs 0.49+/-0.08 mm, p=0.02). Even after adjustment for coronary risk factors and administration of angiotensin converting enzyme inhibitors, the association of hyperinsulinemia with restenosis leads to the conclusion that hyperinsulinemia is a strong risk factor for restenosis.
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Affiliation(s)
- M Imazu
- Second Department of Internal Medicine, Hiroshima University School of Medicine, Japan.
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46
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Xiao J, Gregersen S, Kruhøffer M, Pedersen SB, Ørntoft TF, Hermansen K. The effect of chronic exposure to fatty acids on gene expression in clonal insulin-producing cells: studies using high density oligonucleotide microarray. Endocrinology 2001; 142:4777-84. [PMID: 11606444 DOI: 10.1210/endo.142.11.8483] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Fatty acids affect insulin secretion of pancreatic beta-cells. Investigating gene expression profiles may help to characterize the underlying mechanism. INS-1 cells were cultured with palmitate (0, 50, and 200 microM) for up to 44 d. Insulin secretion and expressions of 8740 genes were studied. We found that basal insulin secretion increased in cells exposed to palmitate. The response to glucose stimulation declined on d 44 in cells cultured at 200 microM palmitate. In response to 50 and 200 microM palmitate exposure, expression was changed in 11 and 99 genes on d 2 and 134 and in 159 genes on d 44, respectively. Genes involved in fatty acid oxidation were up-regulated, whereas those involved in glycolysis were down-regulated with 200 microM palmitate. A suppression of insulin receptor and insulin receptor substate-2 gene expression was found on d 44 in cells cultured at 200 microM palmitate. In conclusion, chronic exposure to low palmitate alters insulin secretion as well as gene expression. The number of genes that changed expression was palmitate dose and exposure time dependent. Randle's fatty acid-glucose cycle seems to be operative on the gene transcription level. A modification of expression of various genes may contribute to the functional changes.
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Affiliation(s)
- J Xiao
- Department of Endocrinology and Metabolism C, Aarhus University Hospital, 8000 Aarhus C, Denmark
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47
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Galipeau D, Arikawa E, Sekirov I, McNeill JH. Chronic Thromboxane Synthase Inhibition Prevents Fructose-Induced Hypertension. Hypertension 2001. [DOI: 10.1161/hyp.38.4.872] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To investigate the role of thromboxane A
2
in the development of hypertension in the fructose-fed rat, we treated male fructose-fed rats with dazmegrel (a thromboxane synthase inhibitor) and monitored blood pressure, fasting plasma parameters, and insulin sensitivity for 7 weeks. Systolic blood pressure was measured each week using tail plethysmography, and an oral glucose tolerance test was performed at the end of the study to assess insulin sensitivity. Treatment with a 60% fructose diet and dazmegrel (100 mg · kg
−1
· d
−1
via oral gavage) was initiated on the same day. Plasma triglyceride levels increased 2-fold in both fructose- and fructose/dazmegrel-treated groups, and plasma insulin levels tended to be higher in these groups, although not significantly. Systolic blood pressure increased significantly throughout the study in the fructose-fed group only (132±3 versus 112±4 mm Hg in control rats, 118±2 mm Hg in control-treated rats, 116±2 mm Hg in fructose-treated rats). Both fructose groups demonstrated a higher peak insulin response to oral glucose challenge and had 40% to 60% lower insulin sensitivity index values. The results of this study show that treatment with a thromboxane synthase inhibitor, dazmegrel, can prevent the development of hypertension but does not improve insulin sensitivity or other fructose-induced metabolic impairments. Based on these data, we conclude that the potent vasoconstrictor thromboxane is involved in the link between hyperinsulinemia/insulin resistance and hypertension.
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Affiliation(s)
- Denise Galipeau
- From the Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Emi Arikawa
- From the Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Inna Sekirov
- From the Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - John H. McNeill
- From the Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
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48
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Abstract
This article describes the benefits of exercise, including why exercise improves blood pressure control, how it may reduce the risk for cancer, and increase mental health, and how it may improve bone mineral density. The article also explores the gender-independent and gender-specific benefits of exercise for women.
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Affiliation(s)
- J L Tanji
- Department of Sports Medicine, University of California, Davis Health System, Sacramento, USA
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Katovich MJ, Pachori A. Effects of inhibition of the renin-angiotensin system on the cardiovascular actions of insulin. Diabetes Obes Metab 2000; 2:3-14. [PMID: 11220351 DOI: 10.1046/j.1463-1326.2000.00044.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- M J Katovich
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville 32610, USA.
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50
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Rupp H, Maisch B. Radiotelemetric characterization of overweight-associated rises in blood pressure and heart rate. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H1540-5. [PMID: 10516193 DOI: 10.1152/ajpheart.1999.277.4.h1540] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We addressed the hypothesis that hypercaloric diets induce hyperkinetic hypertension irrespective of day-night cycle and locomotor activity that is associated with altered cardiac myosin isozymes. Normotensive rats with implanted radiotelemetry pressure transducers were fed increasing amounts of coconut fat (8, 16, and 24%, each for 2 wk) corresponding to 20-47% of total calories from fat. Thereafter, increasing amounts of sucrose (16, 32, and 50%) and fructose (50%) were added to the 24% fat diet corresponding to 13-40% of total calories from sugar. In contrast to the fat diets, the 32% and 50% sucrose diets as well as the 50% fructose diets increased (P < 0.05) blood pressure (systolic maximum +13 mmHg, diastolic maximum +4 mmHg, mean maximum +7 mmHg) and heart rate (maximum +50 beats/min) irrespective of the day-night cycle and the unaltered locomotor activity. Furthermore, body weight increased (P < 0.05) during the 32% and 50% sucrose feedings. The increased blood pressure and heart rate normalized after rats were fed a regular chow. We concluded that an excessive caloric intake results in hyperkinetic hypertension that increases the myosin V(1) proportion.
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Affiliation(s)
- H Rupp
- Molecular Cardiology Laboratory, Department of Internal Medicine, Philipps University of Marburg, 35033 Marburg, Germany.
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