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Krauss RM, Lu JT, Higgins JJ, Clary CM, Tabibiazar R. VLDL receptor gene therapy for reducing atherogenic lipoproteins. Mol Metab 2023; 69:101685. [PMID: 36739970 PMCID: PMC9950951 DOI: 10.1016/j.molmet.2023.101685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/16/2023] [Accepted: 01/29/2023] [Indexed: 02/05/2023] Open
Abstract
Over the past 40 years, there has been considerable research into the management and treatment of atherogenic lipid disorders. Although the majority of treatments and management strategies for cardiovascular disease (CVD) center around targeting low-density lipoprotein cholesterol (LDL-C), there is mounting evidence for the residual CVD risk attributed to high triglyceride (TG) and lipoprotein(a) (Lp(a)) levels despite the presence of lowered LDL-C levels. Among the biological mechanisms for clearing TG-rich lipoproteins, the VLDL receptor (VLDLR) plays a key role in the trafficking and metabolism of lipoprotein particles in multiple tissues, but it is not ordinarily expressed in the liver. Since VLDLR is capable of binding and internalizing apoE-containing TG-rich lipoproteins as well as Lp(a), hepatic VLDLR expression has the potential for promoting clearance of these atherogenic particles from the circulation and managing the residual CVD risk not addressed by current lipid lowering therapies. This review provides an overview of VLDLR function and the potential for developing a genetic medicine based on liver-targeted VLDLR gene expression.
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Affiliation(s)
- Ronald M. Krauss
- University of California, San Francisco, 5700 Martin Luther King, Jr. Way, Oakland CA 94609, USA,Corresponding author.
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Kralova E, Marusakova M, Hadova K, Krenek P, Klimas J. Dapagliflozin elevates plasma high-density lipoprotein levels and influences visceral fat gene expression in streptozotocin-induced diabetes mellitus. J Pharm Pharmacol 2021; 73:778-784. [PMID: 33749792 DOI: 10.1093/jpp/rgab005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 01/13/2021] [Indexed: 01/06/2023]
Abstract
OBJECTIVES Dapagliflozin (Dapa) could potentially be used to treat type 1 diabetes mellitus. We tested the hypothesis that it would influence blood lipid levels and visceral fat accumulation in a rodent diabetic model. METHODS We used three groups of male Wistar rats: Controls, streptozotocin (STZ)-treated rats and STZ-treated orally with Dapa (STZ+Dapa), 10 mg/kg/day for six weeks. Blood glucose and serum lipids levels were determined. Plasma levels of lipases (hormone-sensitive lipase, HSL and lipoprotein lipase, LPL), adipokines (leptin and adiponectin) and proinflammatory cytokines [tumour necrosis factor-alpha (TNFα) and interleukin-6 (IL-6)] were determined by ELISA assays. mRNA levels in the perirenal fat were determined by real-time PCR. KEY FINDINGS Dapa suppressed STZ-related hyperglycemia by 20% (P < 0.05) and increased serum HDL when compared to the controls and the STZ-only treated rats (both P < 0.05). STZ treatment caused elevations of other serum lipids that were resistant to Dapa treatment. Dapa treatment also increased both plasma and visceral fat mRNA levels of leptin, LPL and IL-6, while decreasing plasma and fat expressions of HSL and TNFα compared to the STZ-only treated rats (all P < 0.05). CONCLUSIONS Our results suggest that Dapa, in addition to its antidiabetic effect, also influences the function of adipose tissue which could be beneficial in the treatment of diabetes.
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Affiliation(s)
- Eva Kralova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University in Bratislava, Bratislava, Slovakia
| | - Margareta Marusakova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University in Bratislava, Bratislava, Slovakia
| | - Katarina Hadova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University in Bratislava, Bratislava, Slovakia
| | - Peter Krenek
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University in Bratislava, Bratislava, Slovakia
| | - Jan Klimas
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University in Bratislava, Bratislava, Slovakia
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Tekavec S, Sorčan T, Giacca M, Režen T. VLDL and HDL attenuate endoplasmic reticulum and metabolic stress in HL-1 cardiomyocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158713. [PMID: 32330663 DOI: 10.1016/j.bbalip.2020.158713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 03/06/2020] [Accepted: 04/13/2020] [Indexed: 11/17/2022]
Abstract
Lipoproteins have a vital role in the development of metabolic and cardiovascular diseases ranging from protective to deleterious effects on target tissues. VLDL has been shown to induce lipotoxic lipid accumulation and exert a variety of negative effects on cardiomyocytes. Lipotoxicity and endoplasmic reticulum (ER) stress are proposed to be the mediators of damaging effects of metabolic diseases on cardiovascular system. We treated cardiomyocytes with lipoproteins to evaluate the adaptability of these cells to metabolic stress induced by starvation and excess of lipoproteins, and to evaluate the effect of lipoproteins and lipid accumulation on ER stress. VLDL reversed metabolic stress induced by starvation, while HDL did not. VLDL induced dose-dependent lipid accumulation in cardiomyocytes, which however did not result in reduced cell viability or induction of ER stress. Moreover, VLDL or HDL pre-treatment reduced ER stress in cardiomyocytes induced by tunicamycin and palmitic acid as measured by the expression of ER stress markers, even in conditions of increased lipid accumulation. VLDL and HDL induced activation of pro-survival ERK1/2 in cardiomyocytes; however, this activation was not involved in the protection against ER stress. Additionally, we observed that LDLR and VLDLR are regulated differently by lipoproteins and cellular stress, as lipoproteins induced VLDLR protein independently of the level of lipid accumulation. We conclude that VLDL is not a priori detrimental for cardiomyocytes and can even have beneficial effects, enabling cell survival under starvation and attenuating ER stress.
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Affiliation(s)
- Sara Tekavec
- Centre for Functional Genomics and Bio-Chips, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Tjaša Sorčan
- Centre for Functional Genomics and Bio-Chips, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Mauro Giacca
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Tadeja Režen
- Centre for Functional Genomics and Bio-Chips, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
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Park SO, Zammit VA. In vivo monitoring of hepatic glycolipid distribution of n-6 ∕ n-3 in jugular-vein-cannulated rats as a nutritional research model for monogastric animal. Arch Anim Breed 2019; 62:437-446. [PMID: 31807655 PMCID: PMC6852779 DOI: 10.5194/aab-62-437-2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Accepted: 06/04/2019] [Indexed: 12/13/2022] Open
Abstract
The metabolic distribution via blood from liver of glycerolipids by omega-6
to omega-3 fatty acid (n-6 / n-3) ratio in monogastric animal nutrition is
very important. In vivo monitoring technique using jugular-vein-cannulated
rats as a nutritional model for monogastric animal can yield important
insights into animal nutrition. This study was conducted to determine the
effect of different n-6 / n-3 ratios (71:1, 4:1, 15:1, 30:1) on
metabolic distribution of glycerolipids newly synthesized and secreted in
the liver of the rats and explore the mechanism involved. Regarding
14CO2 released from oxidation of glycerolipid metabolism, it was
the highest (22.5 %) in groups with a n-6 / n-3 ratio of 4:1 (P<0.05).
The control group showed the highest total glycerolipid level, followed by the
30:1, 15:1, and 4:1 groups in order (P<0.05). When secreted
triacylglycerol level of each group was compared with that of the control
group, the 4:1, 15:1, and 30:1 groups were decreased by 36.3 %, 20.9 %, and
13.3 %, respectively (P<0.05). Regarding the distribution of
phospholipid against total glycerolipid compared to the control group, the 4:1, 15:1, and 30:1 groups were 1.38, 1.29, and 1.17 times higher, respectively
(P<0.05). In the comparison of 14CO2 emission against
total glycerolipid compared with the control group, the 4:1, 15:1, and 30:1
groups were 1.61, 1.52, and 1.29 times higher, respectively
(P<0.05). These results demonstrate that a dietary n-6 / n-3 fatty acid
ratio of 4:1 could significantly decrease harmful lipid levels in the blood
by controlling the mechanism of metabolic distribution via blood from
triglyceride and phospholipid newly synthesized in the liver of cannulated
rat.
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Affiliation(s)
- Sang-O Park
- College of Animal Life Science, Kangwon National University, Chuncheon, Gangwon-do, 24419 Republic of Korea
| | - Victor A Zammit
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
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Pendzialek SM, Schindler M, Plösch T, Gürke J, Haucke E, Hecht S, Fischer B, Santos AN. Cholesterol metabolism in rabbit blastocysts under maternal diabetes. Reprod Fertil Dev 2018; 29:1921-1931. [PMID: 27918728 DOI: 10.1071/rd15542] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 10/24/2016] [Indexed: 01/10/2023] Open
Abstract
In the rabbit reproductive model, maternal experimentally induced insulin-dependent diabetes mellitus (expIDD) leads to accumulation of lipid droplets in blastocysts. Cholesterol metabolism is a likely candidate to explain such metabolic changes. Therefore, in the present study we analysed maternal and embryonic cholesterol concentrations and expression of related genes in vivo (diabetic model) and in vitro (embryo culture in hyperglycaemic medium). In pregnant expIDD rabbits, the serum composition of lipoprotein subfractions was changed, with a decrease in high-density lipoprotein cholesterol and an increase in very low-density lipoprotein cholesterol; in uterine fluid, total cholesterol concentrations were elevated. Expression of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), very low-density lipoprotein receptor (VLDLR), sterol regulatory element binding transcription factor 2 (SREBF2), insulin-induced gene-1 (INSIG1) and cholesterol 7α-hydroxylase (CYP7A1) mRNA was decreased in the liver and low-density lipoprotein receptor (LDLR) mRNA expression was decreased in the adipose tissue of diabetic rabbits. In embryos from diabetic rabbits, the mean (±s.e.m.) ratio of cholesterol concentrations in trophoblasts to embryoblasts was changed from 1.27±2.34 (control) to 0.88±3.85 (expIDD). Rabbit blastocysts expressed HMGCR, LDLR, VLDLR, SREBF2 and INSIG1 but not CYP7A1, without any impairment of expression as a result of maternal diabetes. In vitro hyperglycaemia decreased embryonic HMGCR and SREBF2 transcription in rabbit blastocysts. The findings of the present study show that a diabetic pregnancy leads to distinct changes in maternal cholesterol metabolism with a minor effect on embryo cholesterol metabolism.
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Affiliation(s)
- S Mareike Pendzialek
- Department of Anatomy and Cell Biology, Martin Luther University Faculty of Medicine, Grosse Steinstr. 52, 06108 Halle (Saale), Germany
| | - Maria Schindler
- Department of Anatomy and Cell Biology, Martin Luther University Faculty of Medicine, Grosse Steinstr. 52, 06108 Halle (Saale), Germany
| | - Torsten Plösch
- Department of Obstetrics and Gynaecology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 Groningen, The Netherlands
| | - Jacqueline Gürke
- Department of Anatomy and Cell Biology, Martin Luther University Faculty of Medicine, Grosse Steinstr. 52, 06108 Halle (Saale), Germany
| | - Elisa Haucke
- Department of Anatomy and Cell Biology, Martin Luther University Faculty of Medicine, Grosse Steinstr. 52, 06108 Halle (Saale), Germany
| | - Stefanie Hecht
- Department of Anatomy and Cell Biology, Martin Luther University Faculty of Medicine, Grosse Steinstr. 52, 06108 Halle (Saale), Germany
| | - Bernd Fischer
- Department of Anatomy and Cell Biology, Martin Luther University Faculty of Medicine, Grosse Steinstr. 52, 06108 Halle (Saale), Germany
| | - Anne Navarrete Santos
- Department of Anatomy and Cell Biology, Martin Luther University Faculty of Medicine, Grosse Steinstr. 52, 06108 Halle (Saale), Germany
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Evans RD, Hauton D. The role of triacylglycerol in cardiac energy provision. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1481-91. [DOI: 10.1016/j.bbalip.2016.03.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 02/07/2023]
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Nasarre L, Juan-Babot O, Gastelurrutia P, Llucia-Valldeperas A, Badimon L, Bayes-Genis A, Llorente-Cortés V. Low density lipoprotein receptor-related protein 1 is upregulated in epicardial fat from type 2 diabetes mellitus patients and correlates with glucose and triglyceride plasma levels. Acta Diabetol 2014; 51:23-30. [PMID: 23096408 DOI: 10.1007/s00592-012-0436-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 10/08/2012] [Indexed: 11/27/2022]
Abstract
Lipoprotein receptor expression plays a crucial role in the pathophysiology of adipose tissue in in vivo models of diabetes. However, there are no studies in diabetic patients. The aims of this study were to analyze (a) low-density lipoprotein receptor-related protein 1 (LRP1) and very low-density lipoprotein receptor (VLDLR) expression in epicardial and subcutaneous fat from type 2 diabetes mellitus compared with nondiabetic patients and (b) the possible correlation between the expression of these receptors and plasmatic parameters. Adipose tissue biopsy samples were obtained from diabetic (n = 54) and nondiabetic patients (n = 22) undergoing cardiac surgery before the initiation of cardiopulmonary bypass. Adipose LRP1 and VLDLR expression was analyzed at mRNA level by real-time PCR and at protein level by Western blot analysis. Adipose samples were also subjected to lipid extraction, and fat cholesterol ester, triglyceride, and free cholesterol contents were analyzed by thin-layer chromatography. LRP1 expression was higher in epicardial fat from diabetic compared with nondiabetic patients (mRNA 17.63 ± 11.37 versus 7.01 ± 4.86; P = 0.02; protein 11.23 ± 7.23 versus 6.75 ± 5.02, P = 0.04). VLDLR expression was also higher in epicardial fat from diabetic patients but only at mRNA level (231.25 ± 207.57 versus 56.64 ± 45.64, P = 0.02). No differences were found in the expression of LRP1 or VLDLR in the subcutaneous fat from diabetic compared with nondiabetic patients. Epicardial LRP1 and VLDLR mRNA overexpression positively correlated with plasma triglyceride levels (R(2) = 0.50, P = 0.01 and R(2) = 0.44, P = 0.03, respectively) and epicardial LRP1 also correlated with plasma glucose levels (R(2) = 0.33, P = 0.03). These results suggest that epicardial overexpression of certain lipoprotein receptors such as LRP1 and VLDLR expression may play a key role in the alterations of lipid metabolism associated with type 2 diabetes mellitus.
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Affiliation(s)
- L Nasarre
- Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Hospital de la Santa Creu i Sant Pau, UAB, Sant Antoni Mª Claret, 167, 08025, Barcelona, Spain
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Atkinson BJ, Griesel BA, King CD, Josey MA, Olson AL. Moderate GLUT4 overexpression improves insulin sensitivity and fasting triglyceridemia in high-fat diet-fed transgenic mice. Diabetes 2013; 62:2249-58. [PMID: 23474483 PMCID: PMC3712063 DOI: 10.2337/db12-1146] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The GLUT4 facilitative glucose transporter mediates insulin-dependent glucose uptake. We tested the hypothesis that moderate overexpression of human GLUT4 in mice, under the regulation of the human GLUT4 promoter, can prevent the hyperinsulinemia that results from obesity. Transgenic mice engineered to express the human GLUT4 gene and promoter (hGLUT4 TG) and their nontransgenic counterparts (NT) were fed either a control diet (CD) or a high-fat diet (HFD) for up to 10 weeks. Homeostasis model assessment of insulin resistance scores revealed that hGLUT4 TG mice fed an HFD remained highly insulin sensitive. The presence of the GLUT4 transgene did not completely prevent the metabolic adaptations to HFD. For example, HFD resulted in loss of dynamic regulation of the expression of several metabolic genes in the livers of fasted and refed NT and hGLUT4 TG mice. The hGLUT4 TG mice fed a CD showed no feeding-dependent regulation of SREBP-1c and fatty acid synthase (FAS) mRNA expression in the transition from the fasted to the fed state. Similarly, HFD altered the response of SREBP-1c and FAS mRNA expression to feeding in both strains. These changes in hepatic gene expression were accompanied by increased nuclear phospho-CREB in refed mice. Taken together, a moderate increase in expression of GLUT4 is a good target for treatment of insulin resistance.
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9
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Imagawa M, Takahashi S, Zenimaru Y, Kimura T, Suzuki J, Miyamori I, Iwasaki T, Hattori H, Yamamoto TT, Nakano T, Nakajima K. Comparative reactivity of remnant-like lipoprotein particles (RLP) and low-density lipoprotein (LDL) to LDL receptor and VLDL receptor: effect of a high-dose statin on VLDL receptor expression. Clin Chim Acta 2011; 413:441-7. [PMID: 22085424 DOI: 10.1016/j.cca.2011.10.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Revised: 10/24/2011] [Accepted: 10/24/2011] [Indexed: 11/27/2022]
Abstract
BACKGROUND Comparison of the reactivity of remnant-like lipoprotein particles (RLP) and LDL particles to LDL receptor and VLDL receptor has not been investigated. METHODS LDL receptor- or VLDL receptor-transfected ldlA-7, HepG2 and L6 cells were used. Human LDL and rabbit β-VLDL were isolated by ultracentrifugation. Human RLP was isolated using an immunoaffinity mixed gel. The effect of statin on lipoprotein receptors was examined. RESULTS Both LDL receptor and VLDL receptor recognized RLP. In LDL receptor transfectants, RLP, β-VLDL and LDL all bound to LDL receptor. Cold RLP competed efficiently with DiI-β-VLDL; however, cold LDL competed weakly. In VLDL receptor transfectants, RLP and β-VLDL bound to VLDL receptor, but not LDL. RLP bound to VLDL receptor with higher affinity than β-VLDL because of higher apolipoprotein E in RLP. LDL receptor expression was induced in HepG2 by the low concentration of statin while VLDL receptor expression was induced in L6 myoblasts at higher concentration. CONCLUSIONS RLP are bound to hepatic LDL receptor more efficiently than LDL, which may explain the mechanism by which statins prevent cardiovascular risk by primarily reducing plasma RLP rather than by reducing LDL. Additionally, a high-dose of statins also may reduce plasma RLP through muscular VLDL receptor.
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Affiliation(s)
- Michiko Imagawa
- Third Department of Internal Medicine, University of Fukui, Faculty of Medical Science, Japan
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Kim MS, Wang Y, Rodrigues B. Lipoprotein lipase mediated fatty acid delivery and its impact in diabetic cardiomyopathy. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:800-8. [PMID: 22024251 DOI: 10.1016/j.bbalip.2011.10.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Revised: 09/15/2011] [Accepted: 10/03/2011] [Indexed: 01/29/2023]
Abstract
Although cardiovascular disease is the leading cause of diabetes-related death, its etiology is still not understood. The immediate change that occurs in the diabetic heart is altered energy metabolism where in the presence of impaired glucose uptake, glycolysis, and pyruvate oxidation, the heart switches to exclusively using fatty acids (FA) for energy supply. It does this by rapidly amplifying its lipoprotein lipase (LPL-a key enzyme, which hydrolyzes circulating lipoprotein-triglyceride to release FA) activity at the coronary lumen. An abnormally high capillary LPL could provide excess fats to the heart, leading to a number of metabolic, morphological, and mechanical changes, and eventually to cardiac disease. Unlike the initial response, chronic severe diabetes "turns off" LPL, this is also detrimental to cardiac function. In this review, we describe a number of post-translational mechanisms that influence LPL vesicle formation, actin cytoskeleton rearrangement, and transfer of LPL from cardiomyocytes to the vascular lumen to hydrolyze lipoprotein-triglyceride following diabetes. Appreciating the mechanism of how the heart regulates its LPL following diabetes should allow the identification of novel targets for therapeutic intervention, to prevent heart failure. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.
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Affiliation(s)
- Min Suk Kim
- Molecular and Cellular Pharmacology, Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada V6T 1Z3
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Gangula PR, Chinnathambi V, Hale AB, Mukhopadhyay S, Channon KM, Ravella K. Impairment of nitrergic system and delayed gastric emptying in low density lipoprotein receptor deficient female mice. Neurogastroenterol Motil 2011; 23:773-e335. [PMID: 21414103 PMCID: PMC3120899 DOI: 10.1111/j.1365-2982.2011.01695.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND In the current study, we have investigated whether low density lipoprotein receptor knockout mice (LDLR-KO), moderate oxidative stress model and cholesteremia burden display gastroparesis and if so whether nitrergic system is involved in this setting. In addition, we have investigated if sepiapterin (SEP) supplementation attenuated impaired nitrergic system and delayed gastric emptying. METHODS Gastric emptying and nitrergic relaxation were measured in overnight fasting mice. nNOSα dimerization, anti-oxidant markers such as Nrf2, GCLM, GCLC, HO-1, catalase (CAT), and superoxide dismutase (SOD1) were measured using standard methods. Biopterin levels and intestinal transit time were measured using HPLC and dye migration assay, respectively. Wild type (WT) and LDLR-KO were supplemented with SEP. KEY RESULTS In LDLR null stomachs: (i) significant reduction in rate of gastric emptying, gastric pyloric and fundus nitrergic relaxation and nNOSα dimerization, (ii) elevated oxidized biopterins and reduced ratio of BH(4) /BH(2) + B, (iii) reduced Nrf2 and GCLC protein expression and no change in GCLM, HO-1, CAT, SOD1, and (iv) accelerated small intestinal motility were noticed. Supplementation of SEP restored delayed gastric emptying, impaired pyloric and fundus nitrergic relaxation with restoration of nNOS dimerization and nNOS expression. CONCLUSIONS & INFERENCES This novel data suggests that hyperlipidemia and/or suppression of selective antioxidants may be a potential cause of developing gastroparesis in diabetic patients.
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Affiliation(s)
- P R Gangula
- Department of Physiology, Center for Women's Health Research, Meharry Medical College, 1005 Dr. D.B. Todd Jr. Blvd., Nashville, TN 37208, USA.
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Very-low-density lipoprotein: complex particles in cardiac energy metabolism. J Lipids 2011; 2011:189876. [PMID: 21773049 PMCID: PMC3136095 DOI: 10.1155/2011/189876] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Accepted: 05/09/2011] [Indexed: 01/07/2023] Open
Abstract
The heart is a major consumer of energy and is able to utilise a wide range of substrates including lipids. Nonesterified fatty acids (NEFA) were thought to be a favoured carbon source, but their quantitative contribution is limited because of their relative histotoxicity. Circulating triacylglycerols (TAGs) in the form of chylomicrons (CMs) and very-low-density lipoprotein (VLDL) are an alternative source of fatty acids and are now believed to be important in cardiac metabolism. However, few studies on cardiac utilisation of VLDL have been performed and the role of VLDL in cardiac energy metabolism remains unclear. Hearts utilise VLDL to generate ATP, but the oxidation rate of VLDL-TAG is relatively low under physiological conditions; however, in certain pathological states switching of energy substrates occurs and VLDL may become a major energy source for hearts. We review research regarding myocardial utilisation of VLDL and suggest possible roles of VLDL in cardiac energy metabolism: metabolic regulator and extracardiac energy storage for hearts.
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Yuan G, Liu Y, Sun T, Xu Y, Zhang J, Yang Y, Zhang M, Cianflone K, Wang DW. The Therapeutic Role of Very Low-Density Lipoprotein Receptor Gene in Hyperlipidemia in Type 2 Diabetic Rats. Hum Gene Ther 2011; 22:302-12. [PMID: 21087152 DOI: 10.1089/hum.2010.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Gang Yuan
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Yongjian Liu
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
- Department of Endocrinology, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Tingting Sun
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Yongping Xu
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Jianhuan Zhang
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Yan Yang
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Muxun Zhang
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Katherine Cianflone
- Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec, QC, Canada
| | - Dao Wen Wang
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
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de Souza MDSS, Sinzato YK, Lima PHO, Calderon IMP, Rudge MVC, Damasceno DC. Oxidative stress status and lipid profiles of diabetic pregnant rats exposed to cigarette smoke. Reprod Biomed Online 2010; 20:547-52. [PMID: 20153698 DOI: 10.1016/j.rbmo.2010.01.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 08/05/2009] [Accepted: 12/07/2009] [Indexed: 11/24/2022]
Abstract
This study aimed to evaluate the oxidative stress status and the concentrations of triglycerides, cholesterol and total proteins of pregnant rats exposed to the association of diabetes and cigarette smoke. Female Wistar rats were randomly distributed in four experimental groups, according to presence or not of diabetes and the exposure or not to cigarette smoke. Diabetes was induced by streptozotocin (40 mg/kg i.v.) and exposure to cigarette smoke was for 30 min, twice a day, for 2 months. At day 21 of pregnancy, blood was collected for total protein, triglyceride, cholesterol and oxidative stress determinations. Data were analysed by ANOVA followed by Student-Newman-Keuls test (P<0.05). The association of diabetes and exposure to cigarette smoke was related to the incidence of hypertriglyceridaemia, and this result was due to the severe diabetes and not to exposure to smoke. There was no alteration to protein metabolism in pregnant rats. Diabetes and cigarette smoke exposure led to the activation of the antioxidant system in an attempt to detoxify the organism in face of high lipid peroxidation, which can be characterized by the determination of reactive substances to thiobarbituric acid.
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Affiliation(s)
- Maricelma da Silva Soares de Souza
- Laboratory of Experimental Research of Gynecology and Obstetrics, Department of Gynecology and Obstetrics, Botucatu Medical School, UNESP/Univ Estadual Paulista, São Paulo State, Brazil
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15
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Glucose deprivation accelerates VLDL receptor-mediated TG-rich lipoprotein uptake by AMPK activation in skeletal muscle cells. Biochem Biophys Res Commun 2008; 368:716-22. [DOI: 10.1016/j.bbrc.2008.01.154] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Accepted: 01/27/2008] [Indexed: 11/22/2022]
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16
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An D, Rodrigues B. Role of changes in cardiac metabolism in development of diabetic cardiomyopathy. Am J Physiol Heart Circ Physiol 2006; 291:H1489-506. [PMID: 16751293 DOI: 10.1152/ajpheart.00278.2006] [Citation(s) in RCA: 329] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In patients with diabetes, an increased risk of symptomatic heart failure usually develops in the presence of hypertension or ischemic heart disease. However, a predisposition to heart failure might also reflect the effects of underlying abnormalities in diastolic function that can occur in asymptomatic patients with diabetes alone (termed diabetic cardiomyopathy). Evidence of cardiomyopathy has also been demonstrated in animal models of both Type 1 (streptozotocin-induced diabetes) and Type 2 diabetes (Zucker diabetic fatty rats and ob/ob or db/db mice). During insulin resistance or diabetes, the heart rapidly modifies its energy metabolism, resulting in augmented fatty acid and decreased glucose consumption. Accumulating evidence suggests that this alteration of cardiac metabolism plays an important role in the development of cardiomyopathy. Hence, a better understanding of this dysregulation in cardiac substrate utilization during insulin resistance and diabetes could provide information as to potential targets for the treatment of cardiomyopathy. This review is focused on evaluating the acute and chronic regulation and dysregulation of cardiac metabolism in normal and insulin-resistant/diabetic hearts and how these changes could contribute toward the development of cardiomyopathy.
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MESH Headings
- Animals
- Cardiomyopathies/etiology
- Cardiomyopathies/metabolism
- Cardiomyopathies/pathology
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/pathology
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Disease Models, Animal
- Energy Metabolism/physiology
- Fatty Acids/metabolism
- Glucose/metabolism
- Humans
- Insulin Resistance/physiology
- Mice
- Mice, Obese
- Myocardium/metabolism
- Myocardium/pathology
- Rats
- Rats, Zucker
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Affiliation(s)
- Ding An
- Div. of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, The Univ. of British Columbia, 2146 East Mall, Vancouver, BC, Canada
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17
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Shinohara T, Takahashi N, Ooie T, Hara M, Shigematsu S, Nakagawa M, Yonemochi H, Saikawa T, Yoshimatsu H. Phosphatidylinositol 3-kinase-dependent activation of akt, an essential signal for hyperthermia-induced heat-shock protein 72, is attenuated in streptozotocin-induced diabetic heart. Diabetes 2006; 55:1307-15. [PMID: 16644687 DOI: 10.2337/db05-0266] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We tested the hypothesis that phosphatidylinositol 3-kinase (PI 3-kinase)-dependent activation of Akt is essential for the expression of cardiac heat-shock protein 72 (HSP72) and that this pathway is impaired in the streptozotocin (STZ)-induced diabetic heart. STZ-induced male diabetic rats were treated with insulin (STZ-insulin group, n = 26) or vehicle (STZ-vehicle group, n = 61) for 3 weeks. Whole-body hyperthermia (43 degrees C for 20 min) was applied, and the heart was isolated 24 h later. Compared with control heart, hyperthermia-induced HSP72 expression and phosphorylation of Akt were attenuated in the STZ-vehicle heart. Pretreatment with wortmannin attenuated hyperthermia-induced HSP72 expression and phosphorylation of Akt. In isolated perfused heart experiments, the hyperthermia-treated STZ-vehicle heart showed poor left ventricular functional recovery during reperfusion after no-flow global ischemia compared with hyperthermia-treated control heart. Insulin treatment restored HSP72 expression and reperfusion-induced functional recovery. In cultured neonatal rat cardiomyocytes, hyperthermia-induced HSP72 expression was enhanced by insulin, together with tolerance against hypoxia-reoxygenation injury. Wortmannin and LY294002 inhibited hyperthermia-induced HSP72 expression and phosphorylation of Akt. Our results indicate that activation of Akt, in a PI 3-kinase-dependent manner, is essential for hyperthermia-induced HSP72 expression in association with cardioprotection, suggesting impairment of this signaling pathway in the STZ-induced diabetic heart, probably due to insulin deficiency.
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Affiliation(s)
- Tetsuji Shinohara
- Department of Internal Medicine 1, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama, Oita 879-5593, Japan
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