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Samniang B, Shinlapawittayatorn K, Chunchai T, Pongkan W, Kumfu S, Chattipakorn SC, KenKnight BH, Chattipakorn N. Vagus Nerve Stimulation Improves Cardiac Function by Preventing Mitochondrial Dysfunction in Obese-Insulin Resistant Rats. Sci Rep 2016; 6:19749. [PMID: 26830020 PMCID: PMC4735283 DOI: 10.1038/srep19749] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/17/2015] [Indexed: 01/02/2023] Open
Abstract
Long-term high-fat diet (HFD) consumption leads to not only obese-insulin resistance, but also impaired left ventricular (LV) function. Vagus nerve stimulation (VNS) has been shown to exert cardioprotection. However, its effects on the heart and metabolic parameters under obese-insulin resistant condition is not known. We determined the effects of VNS on metabolic parameters, heart rate variability (HRV) and LV function in obese-insulin resistant rats. Male Wistar rats were fed with HFD for 12 weeks, and were randomly divided into sham and VNS groups. VNS was applied for the next 12 weeks. Echocardiography, blood pressure and HRV were examined. Blood samples were collected for metabolic parameters. At the end, the heart was removed for determination of apoptosis, inflammation, oxidative stress, and cardiac mitochondrial function. VNS for 12 weeks significantly decreased plasma insulin, HOMA index, total cholesterol, triglyceride, LDL and visceral fat. Serum adiponectin was significantly increased in the VNS group. VNS also significantly decreased blood pressure, improved HRV and LV function, decreased cardiac MDA, TNF-α and Bax levels, and improved cardiac mitochondrial function. VNS improves metabolic and hemodynamic parameters, and the LV function via its ability against apoptosis, inflammation and oxidative stress, and preserved cardiac mitochondrial function in obese-insulin resistant rats.
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Affiliation(s)
- Bencharunan Samniang
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Center of Excellence in Cardiac Electrophysiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Krekwit Shinlapawittayatorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Center of Excellence in Cardiac Electrophysiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Titikorn Chunchai
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Center of Excellence in Cardiac Electrophysiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Wanpitak Pongkan
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Center of Excellence in Cardiac Electrophysiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Sirinart Kumfu
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Center of Excellence in Cardiac Electrophysiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Siriporn C. Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Center of Excellence in Cardiac Electrophysiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai, 50200, Thailand
| | | | - Nipon Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
- Center of Excellence in Cardiac Electrophysiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
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Yoshida T, Semprun-Prieto L, Wainford RD, Sukhanov S, Kapusta DR, Delafontaine P. Angiotensin II reduces food intake by altering orexigenic neuropeptide expression in the mouse hypothalamus. Endocrinology 2012; 153:1411-20. [PMID: 22234465 PMCID: PMC3281527 DOI: 10.1210/en.2011-1764] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Angiotensin II (Ang II), which is elevated in many chronic disease states such as end-stage renal disease and congestive heart failure, induces cachexia and skeletal muscle wasting by increasing muscle protein breakdown and reducing food intake. Neurohormonal mechanisms that mediate Ang II-induced appetite suppression are unknown. Consequently, we examined the effect of Ang II on expression of genes regulating appetite. Systemic Ang II (1 μg/kg · min) infusion in FVB mice rapidly reduced hypothalamic expression of neuropeptide Y (Npy) and orexin and decreased food intake at 6 h compared with sham-infused controls but did not change peripheral leptin, ghrelin, adiponectin, glucagon-like peptide, peptide YY, or cholecystokinin levels. These effects were completely blocked by the Ang II type I receptor antagonist candesartan or deletion of Ang II type 1a receptor. Ang II markedly reduced phosphorylation of AMP-activated protein kinase (AMPK), an enzyme that is known to regulate Npy expression. Intracerebroventricular Ang II infusion (50 ng/kg · min) caused a reduction of food intake, and Ang II dose dependently reduced Npy and orexin expression in the hypothalamus cultured ex vivo. The reduction of Npy and orexin in hypothalamic cultures was completely prevented by candesartan or the AMPK activator 5-aminoimidazole-4-carboxamide ribonucleoside. Thus, Ang II type 1a receptor-dependent Ang II signaling reduces food intake by suppressing the hypothalamic expression of Npy and orexin, likely via AMPK dephosphorylation. These findings have major implications for understanding mechanisms of cachexia in chronic disease states such as congestive heart failure and end-stage renal disease, in which the renin-angiotensin system is activated.
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Affiliation(s)
- Tadashi Yoshida
- Heart and Vascular Institute, Tulane University School of Medicine, 1430 Tulane Avenue SL-48, New Orleans, Louisiana 70112, USA
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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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Renin-angiotensin system inhibitors suppress azoxymethane-induced colonic preneoplastic lesions in C57BL/KsJ-db/db obese mice. Biochem Biophys Res Commun 2011; 410:108-13. [PMID: 21640075 DOI: 10.1016/j.bbrc.2011.05.115] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 05/19/2011] [Indexed: 12/28/2022]
Abstract
Obesity-related metabolic abnormalities, including chronic inflammation and oxidative stress, increase the risk of colorectal cancer. Dysregulation of the renin-angiotensin system (RAS) also plays a critical role in obesity-related metabolic disorders and in several types of carcinogenesis. In the present study, we examined the effects of an angiotensin-converting enzyme (ACE) inhibitor and angiotensin-II type 1 receptor blocker (ARB), both of which inhibit the RAS, on the development of azoxymethane (AOM)-initiated colonic premalignant lesions in C57BL/KsJ-db/db (db/db) obese mice. Male db/db mice were given 4 weekly subcutaneous injections of AOM (15 mg/kg body weight), and then, they received drinking water containing captopril (ACE inhibitor, 5mg/kg/day) or telmisartan (ARB, 5mg/kg/day) for 7 weeks. At sacrifice, administration of either captopril or telmisartan significantly reduced the total number of colonic premalignant lesions, i.e., aberrant crypt foci and β-catenin accumulated crypts, compared to that observed in the control group. The expression levels of TNF-α mRNA in the colonic mucosa of AOM-treated db/db mice were decreased by captopril and telmisartan. Captopril lowered the expression levels of TNF-α, IL-1β, IL-6, and PAI-1 mRNAs, while telmisartan lowered the expression levels of COX-2, IL-1β, IL-6, and PAI-1 mRNAs in the white adipose tissues of these mice. In addition, these agents significantly reduced the levels of urinary 8-OHdG, a surrogate marker of oxidative damage to DNA, in the experimental mice. These findings suggested that both ACE inhibitor and ARB suppress chemically-induced colon carcinogenesis by attenuating chronic inflammation and reducing oxidative stress in obese mice. Therefore, targeting dysregulation of the RAS might be an effective strategy for chemoprevention of colorectal carcinogenesis in obese individuals.
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Yamamoto R, Akazawa H, Fujihara H, Ozasa Y, Yasuda N, Ito K, Kudo Y, Qin Y, Ueta Y, Komuro I. Angiotensin II type 1 receptor signaling regulates feeding behavior through anorexigenic corticotropin-releasing hormone in hypothalamus. J Biol Chem 2011; 286:21458-65. [PMID: 21525005 DOI: 10.1074/jbc.m110.192260] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The activation of renin-angiotensin system contributes to the development of metabolic syndrome and diabetes as well as hypertension. However, it remains undetermined how renin-angiotensin system is implicated in feeding behavior. Here, we show that angiotensin II type 1 (AT(1)) receptor signaling regulates the hypothalamic neurocircuit that is involved in the control of food intake. Compared with wild-type Agtr1a(+/+) mice, AT(1) receptor knock-out (Agtr1a(-/-)) mice were hyperphagic and obese with increased adiposity on an ad libitum diet, whereas Agtr1a(-/-) mice were lean with decreased adiposity on a pair-fed diet. In the hypothalamus, mRNA levels of anorexigenic neuropeptide corticotropin-releasing hormone (Crh) were lower in Agtr1a(-/-) mice than in Agtr1a(+/+) mice both on an ad libitum and pair-fed diet. Furthermore, intracerebroventricular administration of CRH suppressed food intake both in Agtr1a(+/+) and Agtr1a(-/-) mice. In addition, the Crh gene promoter was significantly transactivated via the cAMP-responsive element by angiotensin II stimulation. These results thus demonstrate that central AT(1) receptor signaling plays a homeostatic role in the regulation of food intake by maintaining gene expression of Crh in hypothalamus and suggest a therapeutic potential of central AT(1) receptor blockade in feeding disorders.
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Affiliation(s)
- Rie Yamamoto
- Department of Cardiovascular Science and Medicine, Chiba University Graduate School of Medicine, Chiba, Chiba 260-8670, Japan
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Effect of the BioEnterics intragastric balloon on weight, insulin resistance, and liver steatosis in obese patients. Gastrointest Endosc 2010; 71:927-33. [PMID: 19863955 DOI: 10.1016/j.gie.2009.06.036] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 06/25/2009] [Indexed: 12/13/2022]
Abstract
BACKGROUND In obese patients, positioning of the BioEnterics intragastric balloon (BIB) proved beneficial for weight loss, but the effect of the device on ameliorating some components of the metabolic syndrome associated with obesity remains uncertain. OBJECTIVE To evaluate the effectiveness of BIB insertion on weight control and amelioration of components of the metabolic syndrome. DESIGN A prospective intervention study performed at baseline, 6 months after BIB insertion, and after a mean (standard deviation [SD]) of 21 (3) months (range 14-26) of follow-up. SETTING Division of Gastroenterology and Endoscopic Unit, "Casa Sollievo della Sofferenza" Hospital. PATIENTS One hundred thirty obese patients with a mean (SD) weight of 118 (24) kg and mean (SD) body mass index (BMI) of 43 (8) kg/m(2). INTERVENTIONS Positioning of BIB. MAIN OUTCOME MEASUREMENTS Anthropometric and laboratory parameters. RESULTS Overall, the mean (SD) weight and BMI decreased by 13.2 (8.2) kg and 5.1 (3.2) kg/m(2), respectively, compared with baseline. The mean glycemia, insulinemia, Homeostasis Model Assessment index, triglyceridemia, and alanine aminotransferase levels were significantly reduced. In the 91 responders (BMI decrease of > or = 3.5 kg/m(2)), the mean (SD) weight and BMI decreased by 16.4 (6.3) kg and 6.4 (2.3) kg/m(2), respectively, and severe liver steatosis decreased from 52% to 4% (P < .0001). On multivariate analysis, severe steatosis and the Homeostasis Model Assessment index were predictive of the response to BIB: odds ratios of 6.71 (95% CI, 2.23-20.19) and 3.18 (95% CI, 1.20-8.42). After a median follow-up of 22 months after BIB removal, 50% of responders maintained or continued to lose weight. LIMITATIONS No sham-treated patients were included as comparative controls. CONCLUSIONS Treatment was effective in inducing weight loss, improving liver steatosis, and restoring some components of the metabolic syndrome.
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Identification of cardiovascular genes in omentum from morbidly obese patients with type 2 diabetes. Int J Obes (Lond) 2010; 34:1020-7. [PMID: 20157321 DOI: 10.1038/ijo.2010.23] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND The metabolic syndrome describes the association between obesity and co-morbidities including insulin resistance, hypertension, dyslipidemia, and cardiovascular (CV) disease. Adipokines produced from omentum contribute to the risk of CV disease and increase the inflammatory state. This study examines the gene expression differences in the omental tissue of morbidly obese diabetic and non-diabetic patients. METHODS Twenty morbidly obese patients undergoing bariatric surgery were included. Ten patients were diabetic and 10 were non-diabetic. Omental samples were collected intraoperatively and snap frozen. Total RNA was extracted using the Trizol reagent and purified with the RNeasy kit (Qiagen). Microarray experiments were performed using the Affymetrix Gene 1.0 ST array and data was analyzed with the Partek 6.3 program using an unpaired t-test (P<0.05). The gene expression profiles of the diabetic group were compared with the non-diabetic group. Using the Ingenuity program, the gene list generated from the microarray analysis was evaluated and real-time quantitative PCR (qPCR) was used to validate the array data. RESULTS Compared with the non-diabetic group, the diabetic obese patients showed 79 upregulated genes and 4 downregulated genes with >1.4-fold difference in expression. Ingenuity analysis showed numerous dysregulated genes associated with CV disease including leptin, Von Willebrand factor, P-selectin, angiopoietin-1 (ANGPT1), phospholipase A2 (group VII), and periostin osteoblast specific factor. Microarray results for the earlier mentioned genes were confirmed with qPCR. The results were analyzed with respect to the presence or absence of hyperlipidemia, hypertension, and coronary artery disease. In patients with hyperlipidemia, ANGPT1 and P-selectin were upregulated 1.9- and 2.9-fold, respectively. CONCLUSIONS This microarray analysis of omental tissue from morbidly obese diabetic patients documents a host of upregulated genes related to CV disease. This study provides further evidence that diabetic status predisposes obese patients to a higher risk of developing CV disease.
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Katare RG, Kakinuma Y, Arikawa M, Yamasaki F, Sato T. Chronic intermittent fasting improves the survival following large myocardial ischemia by activation of BDNF/VEGF/PI3K signaling pathway. J Mol Cell Cardiol 2008; 46:405-12. [PMID: 19059263 DOI: 10.1016/j.yjmcc.2008.10.027] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 10/22/2008] [Accepted: 10/24/2008] [Indexed: 10/21/2022]
Abstract
Chronic heart failure (CHF) is the major cause of death in the developed countries. Calorie restriction is known to improve the recovery in these patients; however, the exact mechanism behind this protective effect is unknown. Here we demonstrate the activation of cell survival PI3kinase/Akt and VEGF pathway as the mechanism behind the protection induced by intermittent fasting in a rat model of established chronic myocardial ischemia (MI). Chronic MI was induced in rats by occlusion of the left coronary artery. Two weeks later, the rats were randomly assigned to a normal feeding group (MI-NF) and an alternate-day feeding group (MI-IF). After 6 weeks of observation, we evaluated the effect of intermittent fasting on cellular and ventricular remodeling and long-term survival after CHF. Compared with the normally fed group, intermittent fasting markedly improved the survival of rats with CHF (88.5% versus 23% survival, P<0.05). The heart weight body weight ratio was significantly less in the MI-IF group compared to the MI-NF group (3.4+/-0.17 versus 3.9+/-0.18, P<0.05). Isolated heart perfusion studies exhibited well preserved cardiac functions in the MI-IF group compared to the MI-NF group (P<0.05). Molecular studies revealed the upregulation of angiogenic factors such asHIF-1-alpha (3010+/-350% versus 650+/-151%), BDNF (523+/-32% versus 110+/-12%), and VEGF (450+/-21% versus 170+/-30%) in the fasted hearts. Immunohistochemical studies confirmed increased capillary density (P<0.001) in the border area of the ischemic myocardium and synthesis VEGF by cardiomyocytes. Moreover fasting also upregulated the expression of other anti-apoptotic factors such as Akt and Bcl-2 and reduced the TUNEL positive apoptotic nuclei in the border zone. Chronic intermittent fasting markedly improves the long-term survival after CHF by activation through its pro-angiogenic, anti-apoptotic and anti-remodeling effects.
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Affiliation(s)
- Rajesh G Katare
- Department of Cardiovascular Control, Kochi Medical School, Nankoku, Kochi, Japan.
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