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Nelson MAM, Efird JT, Kew KA, Katunga LA, Monroe TB, Doorn JA, Beatty CN, Shi Q, Akhter SA, Alwair H, Robidoux J, Anderson EJ. Enhanced Catecholamine Flux and Impaired Carbonyl Metabolism Disrupt Cardiac Mitochondrial Oxidative Phosphorylation in Diabetes Patients. Antioxid Redox Signal 2021; 35:235-251. [PMID: 33066717 PMCID: PMC8262387 DOI: 10.1089/ars.2020.8122] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Aims: Catecholamine metabolism via monoamine oxidase (MAO) contributes to cardiac injury in models of ischemia and diabetes, but the pathogenic mechanisms involved are unclear. MAO deaminates norepinephrine (NE) and dopamine to produce H2O2 and highly reactive "catecholaldehydes," which may be toxic to mitochondria due to the localization of MAO to the outer mitochondrial membrane. We performed a comprehensive analysis of catecholamine metabolism and its impact on mitochondrial energetics in atrial myocardium obtained from patients with and without type 2 diabetes. Results: Content and maximal activity of MAO-A and MAO-B were higher in the myocardium of patients with diabetes and they were associated with body mass index. Metabolomic analysis of atrial tissue from these patients showed decreased catecholamine levels in the myocardium, supporting an increased flux through MAOs. Catecholaldehyde-modified protein adducts were more abundant in myocardial tissue extracts from patients with diabetes and were confirmed to be MAO dependent. NE treatment suppressed mitochondrial ATP production in permeabilized myofibers from patients with diabetes in an MAO-dependent manner. Aldehyde dehydrogenase (ALDH) activity was substantially decreased in atrial myocardium from these patients, and metabolomics confirmed lower levels of ALDH-catalyzed catecholamine metabolites. Proteomic analysis of catechol-modified proteins in isolated cardiac mitochondria from these patients identified >300 mitochondrial proteins to be potential targets of these unique carbonyls. Innovation and Conclusion: These findings illustrate a unique form of carbonyl toxicity driven by MAO-mediated metabolism of catecholamines, and they reveal pathogenic factors underlying cardiometabolic disease. Importantly, they suggest that pharmacotherapies targeting aldehyde stress and catecholamine metabolism in heart may be beneficial in patients with diabetes and cardiac disease. Antioxid. Redox Signal. 35, 235-251.
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Affiliation(s)
- Margaret-Ann M Nelson
- Department of Pharmacology & Toxicology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Jimmy T Efird
- Centre for Clinical Epidemiology and Biostatistics, School of Medicine and Public Health, University of Newcastle, Newcastle, Australia
| | - Kimberly A Kew
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Lalage A Katunga
- Department of Pharmacology & Toxicology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - T Blake Monroe
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, Iowa, USA
| | - Jonathan A Doorn
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, Iowa, USA
| | - Cherese N Beatty
- Department of Pharmacology & Toxicology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Qian Shi
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Shahab A Akhter
- Department of Cardiovascular Sciences, Brody School of Medicine, East Carolina Heart Institute, Greenville, North Carolina, USA
| | - Hazaim Alwair
- Department of Cardiovascular Sciences, Brody School of Medicine, East Carolina Heart Institute, Greenville, North Carolina, USA
| | - Jacques Robidoux
- Department of Pharmacology & Toxicology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Ethan J Anderson
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
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Kusmic C, Giorgetti A, Barsanti C, Burchielli S, Petroni D, Kusch A, Genovesi D, Menichetti L, Marzullo P. Spatial Inhomogeneity of Cardiac Norepinephrine Transport Protein and Meta-[ 123I]Iodobenzylguanidine Uptake in Swine Myocardial Tissue. Mol Imaging Biol 2018; 21:482-490. [PMID: 30187232 DOI: 10.1007/s11307-018-1269-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
PURPOSE The aim of the present study was to evaluate the expression of the cardiac norepinephrine transporter (NET) in the left ventricle (LV) of healthy pigs and its relationship with regional meta-[123I]iodobenzylguanidine ([123I]MIBG) myocardial uptake. PROCEDURES Experiments were performed on animals injected with [123I]MIBG and acquired 2 h later using an ultrafast CZT gamma camera to assess the regional myocardial uptake. After image acquisition, animals were euthanized; the heart was quickly excised and underwent to an ex vivo single photon emission tomography (SPECT) imaging. Four small samples of tissue were then harvested from mid-walls and apex of the left ventricle; NET densities were evaluated and further normalized for protein loading per cardiac region. RESULTS Three variants of NET protein with different molecular weights were detected. The expression of NET was not homogenous in the LV, with the highest density in the inferior wall and the lowest one in the apical area. The regional in vivo [123I]MIBG uptake revealed an analogous trend, showing a good linear relationship with NET expression. Parallel results were obtained from the ex vivo study. CONCLUSION This study elucidates the expression of three different variants of NET proteins into the left ventricular myocardium of a healthy pig. NET expression into the LV was not homogeneous and paralleled by differences in regional [123I]MIBG uptake. Moreover, the correlation and the agreement between measurements of regional expression of NET variants and [123I]MIBG uptake represent a relevant finding for inferences about NET expression in the context of clinical imaging.
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Affiliation(s)
- Claudia Kusmic
- Institute of Clinical Physiology, Consiglio Nazionale delle Ricerche (CNR), Via Moruzzi, 1, 56124, Pisa, Italy.
| | - Assuero Giorgetti
- Fondazione Toscana G. Monasterio, Via Moruzzi, 1, 56124, Pisa, Italy.
| | - Cristina Barsanti
- Institute of Clinical Physiology, Consiglio Nazionale delle Ricerche (CNR), Via Moruzzi, 1, 56124, Pisa, Italy
| | - Silvia Burchielli
- Fondazione Toscana G. Monasterio, Via Moruzzi, 1, 56124, Pisa, Italy
| | - Debora Petroni
- Institute of Clinical Physiology, Consiglio Nazionale delle Ricerche (CNR), Via Moruzzi, 1, 56124, Pisa, Italy
| | - Annette Kusch
- Fondazione Toscana G. Monasterio, Via Moruzzi, 1, 56124, Pisa, Italy
| | - Dario Genovesi
- Fondazione Toscana G. Monasterio, Via Moruzzi, 1, 56124, Pisa, Italy
| | - Luca Menichetti
- Institute of Clinical Physiology, Consiglio Nazionale delle Ricerche (CNR), Via Moruzzi, 1, 56124, Pisa, Italy.,Fondazione Toscana G. Monasterio, Via Moruzzi, 1, 56124, Pisa, Italy
| | - Paolo Marzullo
- Institute of Clinical Physiology, Consiglio Nazionale delle Ricerche (CNR), Via Moruzzi, 1, 56124, Pisa, Italy.,Fondazione Toscana G. Monasterio, Via Moruzzi, 1, 56124, Pisa, Italy
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Capitanio S, Nanni C, Marini C, Bonfiglioli R, Martignani C, Dib B, Fuccio C, Boriani G, Picori L, Boschi S, Morbelli S, Fanti S, Sambuceti G. Heterogeneous response of cardiac sympathetic function to cardiac resynchronization therapy in heart failure documented by 11[C]-hydroxy-ephedrine and PET/CT. Nucl Med Biol 2015; 42:858-63. [PMID: 26239084 DOI: 10.1016/j.nucmedbio.2015.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 05/30/2015] [Accepted: 07/05/2015] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Cardiac resynchronization therapy (CRT) is an accepted treatment in patients with end-stage heart failure. PET permits the absolute quantification of global and regional homogeneity in cardiac sympathetic innervation. We evaluated the variation of cardiac adrenergic activity in patients with idiopathic heart failure (IHF) disease (NYHA III-IV) after CRT using (11)C-hydroxyephedrine (HED) PET/CT. METHODS Ten IHF patients (mean age = 68; range = 55-81; average left ventricular ejection fraction 26 ± 4%) implanted with a resynchronization device underwent three HED PET/CT studies: PET 1 one week after inactive device implantation; PET 2, one week after PET 1 under stimulated rhythm; PET 3, at 3 months under active CRT. A dedicated software (PMOD 3.4 version) was used to estimate global and regional cardiac uptake of HED through 17 segment polar maps. RESULTS At baseline, HED uptake was heterogeneously distributed throughout the left ventricle with a variation coefficient of 18 ± 5%. This variable markedly decreased after three months CRT (12 ± 5%, p < 0.01). Interestingly, subdividing the 170 myocardial segments (17 segments of each patient multiplied by the number of patients) into two groups, according to the median value of tracer uptake expressed as % of maximal myocardial uptake (76%), we observed a different behaviour depending on baseline innervation: HED uptake significantly increased only in segments with "impaired innervation" (SUV 2.61 ± 0.92 at PET1 and 3.05 ± 1.67 at three months, p < 0.01). CONCLUSION As shown by HED PET/CT uptake and distribution, improvement in homogeneity of myocardial neuronal function reflected a selective improvement of tracer uptake in regions with more severe neuronal damage. ADVANCES IN KNOWLEDGE These finding supported the presence of a myocardial regional variability in response of cardiac sympathetic system to CRT and a systemic response involving remote tissues with rich adrenergic innervation. IMPLICATION FOR PATIENT CARE This work might contribute to identify imaging parameters that could predict the response to CRT therapy.
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Affiliation(s)
- Selene Capitanio
- Nuclear Medicine, IRCCS AOU San Martino-IST, Department of Health Sciences, University of Genoa, Genoa, Italy
| | - Cristina Nanni
- Nuclear Medicine, Hematology-Oncology and Laboratory Medicine Department, Azienda Ospedaliero-Universitaria di Bologna Policlinico Sant' Orsola-Malpighi, University of Bologna, Italy
| | - Cecilia Marini
- CNR Institute of Bioimages and Molecular Physiology, Milan, Section of Genoa, Italy
| | - Rachele Bonfiglioli
- Nuclear Medicine, Hematology-Oncology and Laboratory Medicine Department, Azienda Ospedaliero-Universitaria di Bologna Policlinico Sant' Orsola-Malpighi, University of Bologna, Italy
| | - Cristian Martignani
- Istitute of Cardiology, Azienda Ospedaliero-Universitaria di Bologna Policlinico Sant' Orsola-Malpighi, University of Bologna, Italy
| | - Bassam Dib
- Nuclear Medicine, IRCCS AOU San Martino-IST, Department of Health Sciences, University of Genoa, Genoa, Italy
| | - Chiara Fuccio
- Nuclear Medicine, Hematology-Oncology and Laboratory Medicine Department, Azienda Ospedaliero-Universitaria di Bologna Policlinico Sant' Orsola-Malpighi, University of Bologna, Italy
| | - Giuseppe Boriani
- Istitute of Cardiology, Azienda Ospedaliero-Universitaria di Bologna Policlinico Sant' Orsola-Malpighi, University of Bologna, Italy
| | - Lorena Picori
- Nuclear Medicine, IRCCS AOU San Martino-IST, Department of Health Sciences, University of Genoa, Genoa, Italy
| | - Stefano Boschi
- Nuclear Medicine, Hematology-Oncology and Laboratory Medicine Department, Azienda Ospedaliero-Universitaria di Bologna Policlinico Sant' Orsola-Malpighi, University of Bologna, Italy
| | - Silvia Morbelli
- Nuclear Medicine, IRCCS AOU San Martino-IST, Department of Health Sciences, University of Genoa, Genoa, Italy
| | - Stefano Fanti
- Nuclear Medicine, Hematology-Oncology and Laboratory Medicine Department, Azienda Ospedaliero-Universitaria di Bologna Policlinico Sant' Orsola-Malpighi, University of Bologna, Italy
| | - Gianmario Sambuceti
- Nuclear Medicine, IRCCS AOU San Martino-IST, Department of Health Sciences, University of Genoa, Genoa, Italy.
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Thackeray JT, deKemp RA, Beanlands RS, DaSilva JN. Early diabetes treatment does not prevent sympathetic dysinnervation in the streptozotocin diabetic rat heart. J Nucl Cardiol 2014; 21:829-41. [PMID: 24890379 DOI: 10.1007/s12350-014-9900-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 03/03/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND Positron emission tomography (PET) studies have demonstrated reduced sympathetic neuronal integrity in high-fat diet fed streptozotocin insulin-resistant diabetic rats in parallel with abnormal early-to-atrial transmitral velocity. We hypothesized that administration of anti-glycemic drugs early after diabetes induction would prevent sympathetic neuronal dysfunction. METHODS AND RESULTS Male Sprague-Dawley rats fed high-fat diet were administered streptozotocin (45 mg·kg(-1), ip, n = 23) to induce diabetes or vehicle alone (n = 6). Diabetic rats were randomized to receive insulin (4 U·day(-1)), metformin (650 mg·kg(-1)·day(-1)), rosiglitazone (4 mg·kg(-1)·day(-1)), or no treatment 1 week after streptozotocin. Small animal PET imaging using the norepinephrine analog [(11)C]meta-hydroxyephedrine (HED) at baseline and 8 weeks of diabetes determined sympathetic neuronal integrity. Echocardiography assessed cardiac function. Plasma norepinephrine levels were determined in parallel. Ex vivo immunoblotting was performed at the end of the experiment to compare the relative expression of various proteins involved in metabolic and noradrenergic signaling. Insulin restored blood glucose and lipid levels to normal. Despite improved plasma lipid levels, neither metformin nor rosiglitazone reduced blood glucose. At 8 weeks, untreated and treated diabetics displayed a 39%-42% reduction in myocardial HED standardized uptake values (P < .05). In all diabetic groups, plasma norepinephrine was elevated (2.3- to 3.3-fold, P < .05) and norepinephrine reuptake transporter expression reduced (28%-35%, P < .05) compared to non-diabetics. Doppler echocardiography revealed delayed development of prolonged mitral valve deceleration and elevated early-to-atrial filling velocity ratio among treated diabetic rats. CONCLUSION Early glycemic treatment of insulin-resistant diabetic rats did not prevent deterioration of sympathetic neuronal integrity though ventricular filling abnormalities were delayed.
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Affiliation(s)
- James T Thackeray
- Molecular Function & Imaging Program, National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON, K1Y4W7, Canada
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Marangoni MN, Brady ST, Chowdhury SA, Piano MR. The co-occurrence of myocardial dysfunction and peripheral insensate neuropathy in a streptozotocin-induced rat model of diabetes. Cardiovasc Diabetol 2014; 13:11. [PMID: 24410801 PMCID: PMC3893387 DOI: 10.1186/1475-2840-13-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 12/30/2013] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Cardiomyopathy and distal symmetrical polyneuropathy (DSPN), including sensory and autonomic dysfunction, often co-occur in diabetic mellitus (DM) patients. However, the temporal relationship and progression between these two complications has not been investigated. Using a streptozotocin DM animal model that develops insensate neuropathy, our aim was to examine in parallel the development of DSPN and DM-associated changes in cardiac structure and function as well as potential mechanisms, such as autonomic dysfunction, evaluated by changes in urinary and myocardial norepinephrine content and myocardial neuronal markers. METHODS Sensory neuropathy was measured by behavioral tests using Von Frey filaments and Hargreaves methods. Echocardiography was used to evaluate myocardial structure and function. Autonomic function was evaluated by measuring urinary and myocardial norepinephrine (NE) levels by enzyme-linked immunosorbent assay and high-performance liquid chromatography/mass spectrometry. Quantitative immunohistochemistry was used to measure the myocardial neuronal markers, calcitonin gene-related peptide (CGRP) and general neuronal protein gene product 9.5 (PGP 9.5). RESULTS The DM group developed tactile and thermal insensate neuropathy 4-5 weeks after DM onset. Cardiovascular changes were found between 4 and 12 weeks after DM onset and included bradycardia, diastolic and systolic dysfunction and cardiac dilation. There was a 2.5-fold reduction in myocardial NE levels and a 5-fold increase in urinary NE levels in the DM group. Finally, there was a 2.3-fold increase in myocardial CGRP levels in the DM group and no change in PGP9.5 levels. CONCLUSIONS Cardiovascular structural and functional changes developed early in the course of DM and in combination with insensate neuropathy. In parallel, signs of cardiac autonomic dysfunction were also found and included decreased myocardial NE levels and altered CGRP levels. These results may indicate the need for early cardiovascular evaluation in DM patients with insensate neuropathy.
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Affiliation(s)
| | | | | | - Mariann R Piano
- Department of Biobehavioral Health Science, University of Illinois at Chicago, 845 South Damen Avenue, Room 706 (M/C 802), Chicago, IL 60612-7350, USA.
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Thackeray JT, deKemp RA, Beanlands RS, DaSilva JN. Insulin restores myocardial presynaptic sympathetic neuronal integrity in insulin-resistant diabetic rats. J Nucl Cardiol 2013; 20:845-56. [PMID: 23842711 DOI: 10.1007/s12350-013-9759-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 06/27/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Diabetes is associated with increased sympathetic activity, elevated norepinephrine, impaired heart rate variability, and the added risk of cardiovascular mortality. The temporal development of sympathetic neuronal dysfunction, response to therapy, and relation to ventricular function is not well characterized. METHODS AND RESULTS Sympathetic neuronal integrity was serially investigated in high fat diet-fed streptozotocin diabetic rats using [(11)C]meta-hydroxyephedrine (HED) positron emission tomography at baseline, 8 weeks of diabetes, and after a further 8 weeks of insulin or insulin-sensitizing metformin therapy. Myocardial HED retention was reduced in diabetic rats (n = 16) compared to non-diabetics (n = 6) at 8 weeks by 52-57% (P = .01) with elevated plasma and myocardial norepinephrine levels. Echocardiography pulse-wave Doppler measurements demonstrated prolonged mitral valve deceleration and increased early-to-atrial filling velocity, consistent with diastolic dysfunction. Insulin but not metformin evoked recovery of HED retention and plasma norepinephrine (P < .05), whereas echocardiography measurements of diastolic function were not improved by either treatment. Relative expressions of norepinephrine reuptake transporter and β-adrenoceptors were lower in metformin-treated as compared to insulin-treated diabetic and non-diabetic rats. Diabetic rats exhibited depressed heart rate variability and impaired diastolic function which persisted despite insulin treatment. CONCLUSIONS HED imaging provides sound estimation of sympathetic function. Effective glycemic control can recover sympathetic function in diabetic rats without the corresponding recovery of echocardiography indicators of diastolic dysfunction. HED positron emission tomography imaging may be useful in stratifying cardiovascular risk among diabetic patients and in evaluating the effect of glycemic therapy on the heart.
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Affiliation(s)
- James T Thackeray
- Molecular Function & Imaging Program, National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON, K1Y 4W7, Canada,
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Diabetic cardiac autonomic neuropathy: insights from animal models. Auton Neurosci 2013; 177:74-80. [PMID: 23562143 DOI: 10.1016/j.autneu.2013.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 03/01/2013] [Indexed: 12/19/2022]
Abstract
Cardiac autonomic neuropathy (CAN) is a relatively common and often devastating complication of diabetes. The major clinical signs are tachycardia, exercise intolerance, and orthostatic hypotension, but the most severe aspects of this complication are high rates of cardiac events and mortality. One of the earliest manifestations of CAN is reduced heart rate variability, and detection of this, along with abnormal results in postural blood pressure testing and/or the Valsalva maneuver, are central to diagnosis of the disease. The treatment options for CAN, beyond glycemic control, are extremely limited and lack evidence of efficacy. The underlying molecular mechanisms are also poorly understood. Thus, CAN is associated with a poor prognosis and there is a compelling need for research to understand, prevent, and reverse CAN. In this review of the literature we examine the use and usefulness of animal models of CAN in diabetes. Compared to other diabetic complications, the number of animal studies of CAN is very low. The published studies range across a variety of species, methods of inducing diabetes, and timescales examined, leading to high variability in study outcomes. The lack of well-characterized animal models makes it difficult to judge the relevance of these models to the human disease. One major advantage of animal studies is the ability to probe underlying molecular mechanisms, and the limited numbers of mechanistic studies conducted to date are outlined. Thus, while animal models of CAN in diabetes are crucial to better understanding and development of therapies, they are currently under-used.
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Thackeray JT, Radziuk J, Harper ME, Suuronen EJ, Ascah KJ, Beanlands RS, Dasilva JN. Sympathetic nervous dysregulation in the absence of systolic left ventricular dysfunction in a rat model of insulin resistance with hyperglycemia. Cardiovasc Diabetol 2011; 10:75. [PMID: 21831292 PMCID: PMC3170183 DOI: 10.1186/1475-2840-10-75] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 08/10/2011] [Indexed: 12/19/2022] Open
Abstract
Background Diabetes mellitus is strongly associated with cardiovascular dysfunction, derived in part from impairment of sympathetic nervous system signaling. Glucose, insulin, and non-esterified fatty acids are potent stimulants of sympathetic activity and norepinephrine (NE) release. We hypothesized that sustained hyperglycemia in the high fat diet-fed streptozotocin (STZ) rat model of sustained hyperglycemia with insulin resistance would exhibit progressive sympathetic nervous dysfunction in parallel with deteriorating myocardial systolic and/or diastolic function. Methods Cardiac sympathetic nervous integrity was investigated in vivo via biodistribution of the positron emission tomography radiotracer and NE analogue [11C]meta-hydroxyephedrine ([11C]HED). Cardiac systolic and diastolic function was evaluated by echocardiography. Plasma and cardiac NE levels and NE reuptake transporter (NET) expression were evaluated as correlative measurements. Results The animal model displays insulin resistance, sustained hyperglycemia, and progressive hypoinsulinemia. After 8 weeks of persistent hyperglycemia, there was a significant 13-25% reduction in [11C]HED retention in myocardium of STZ-treated hyperglycemic but not euglycemic rats as compared to controls. There was a parallel 17% reduction in immunoblot density for NE reuptake transporter, a 1.2 fold and 2.5 fold elevation of cardiac and plasma NE respectively, and no change in sympathetic nerve density. No change in ejection fraction or fractional area change was detected by echocardiography. Reduced heart rate, prolonged mitral valve deceleration time, and elevated transmitral early to atrial flow velocity ratio measured by pulse-wave Doppler in hyperglycemic rats suggest diastolic impairment of the left ventricle. Conclusions Taken together, these data suggest that sustained hyperglycemia is associated with elevated myocardial NE content and dysregulation of sympathetic nervous system signaling in the absence of systolic impairment.
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Affiliation(s)
- James T Thackeray
- Molecular Function & Imaging Program, National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, K1Y 4W7, Canada
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Whole Body and Cardiac Metaiodobenzylguanidine Kinetics in Parkinson Disease and Multiple System Atrophy. Clin Nucl Med 2010; 35:311-6. [DOI: 10.1097/rlu.0b013e3181d62686] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Goethals LR, Weytjens CD, De Geeter F, Droogmans S, Caveliers V, Keyaerts M, Vanhove C, Van Camp G, Bossuyt A, Lahoutte T. Regional quantitative analysis of small animal myocardial sympathetic innervation and initial application in streptozotocin induced diabetes. CONTRAST MEDIA & MOLECULAR IMAGING 2009; 4:174-82. [DOI: 10.1002/cmmi.278] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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