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Sharma N, Okere IC, Barrows BR, Lei B, Duda MK, Yuan CL, Previs SF, Sharov VG, Azimzadeh AM, Ernsberger P, Hoit BD, Sabbah H, Stanley WC. High-sugar diets increase cardiac dysfunction and mortality in hypertension compared to low-carbohydrate or high-starch diets. J Hypertens 2008; 26:1402-10. [PMID: 18551017 DOI: 10.1097/hjh.0b013e3283007dda] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Sugar consumption affects insulin release and, in hypertension, may stimulate cardiac signaling mechanisms that accelerate left ventricular hypertrophy and the development of heart failure. We investigated the effects of high-fructose or sucrose diets on ventricular function and mortality in hypertensive Dahl salt-sensitive rats. METHODS Rats were fed chows that were either high starch (70% starch, 10% fat by energy), high fat (20% carbohydrates, 60% fat), high fructose (61% fructose, 9% starch, 10% fat), or high sucrose (61% sucrose, 9% starch, 10% fat). Hypertension was induced by adding 6% salt to the chow (n = 8-11/group). RESULTS After 8 weeks of treatment, systolic blood pressure and left ventricular mass were similarly increased in all rats that were fed high-salt diets. Hypertension caused a switch in mRNA myosin heavy chain isoform from alpha to beta, and this effect was greater in the high-salt sucrose and fructose groups than in starch and fat groups. The cardiac mRNA for atrial natriuretic factor was also increased in all high-salt groups compared to respective controls, with the increase being significantly greater in the hypertensive sucrose fed group. Mortality was greater in the sucrose group (44%) compared to all the other hypertensive groups (12-18%), as was cardiomyocyte apoptosis. Left ventricular ejection fraction was lower in the high-salt sucrose group, which was due to an increase in end-systolic volume, and not increased end-diastolic volume. CONCLUSION Diets high in sugar accelerated cardiac systolic dysfunction and mortality in hypertension compared to either a low-carbohydrate/high-fat or high-starch diet.
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Affiliation(s)
- Naveen Sharma
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
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Sharma N, Okere IC, Duda MK, Johnson J, Yuan CL, Chandler MP, Ernsberger P, Hoit BD, Stanley WC. High fructose diet increases mortality in hypertensive rats compared to a complex carbohydrate or high fat diet. Am J Hypertens 2007; 20:403-9. [PMID: 17386347 DOI: 10.1016/j.amjhyper.2006.09.022] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Revised: 09/10/2006] [Accepted: 09/27/2006] [Indexed: 10/23/2022] Open
Abstract
BACKGROUND Chronic hypertension leads to cardiac hypertrophy, heart failure, and premature death. Little is known about the impact of dietary macronutrient composition on hypertension-induced cardiac hypertrophy and mortality. We investigated the effects of consuming either a high complex carbohydrate diet, a high simple sugar diet, or a high fat diet on cardiac hypertrophy and mortality in hypertensive Dahl salt-sensitive (DSS) rats. METHODS Rats were assigned to four diets: complex carbohydrate (CC; 70% starch, 10% fat, 20% protein by energy), high fat (FAT; 20% carbohydrates, 60% fat, 20% protein), high fructose (FRU; 70% fructose, 10% fat, 20% protein), and "western" (WES; 35% fructose, 45% fat, 20% protein). Hypertension was initiated by adding 6% NaCl (+S) to the chow of half the animals within each diet (n = 10 to 13/group). Tail cuff blood pressure measurements were assessed after 5 and 11 weeks of treatment, and echocardiography were assessed after 12 weeks of treatment. RESULTS All rats fed a high salt diet had similar levels of hypertension (CC+S 220 +/-2 mm Hg, FAT+S 221 +/- 3 mm Hg, FRU+S 221 +/- 1 mm Hg, WES+S 226 +/- 3 mm Hg). Echocardiography results show that the addition of salt to FRU resulted in increased regional wall thickness that was not observed in other dietary groups. All rats fed a low salt diet (CC, FAT, FRU, WES) and the FAT+S group survived 90 days. On the other hand, there was 90-day mortality in the WES+S group (18% mortality) and the CC+S group (30% mortality). In addition, FRU+S rats started dying after 45 days of salt feeding, and only 15% survived the full 90 days. CONCLUSIONS These results demonstrate that a high fructose diet consumed during hypertension increases mortality and left ventricular (LV) wall thickness compared to either a high fat, high starch, or a "western" diet.
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Affiliation(s)
- Naveen Sharma
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4970, USA
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Rennison JH, McElfresh TA, Okere IC, Vazquez EJ, Patel HV, Foster AB, Patel KK, Chen Q, Hoit BD, Tserng KY, Hassan MO, Hoppel CL, Chandler MP. High-fat diet postinfarction enhances mitochondrial function and does not exacerbate left ventricular dysfunction. Am J Physiol Heart Circ Physiol 2007; 292:H1498-506. [PMID: 17114240 DOI: 10.1152/ajpheart.01021.2006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Lipid accumulation in nonadipose tissue due to enhanced circulating fatty acids may play a role in the pathophysiology of heart failure, obesity, and diabetes. Accumulation of myocardial lipids and related intermediates, e.g., ceramide, is associated with decreased contractile function, mitochondrial oxidative phosphorylation, and electron transport chain (ETC) complex activities. We tested the hypothesis that the progression of heart failure would be exacerbated by elevated myocardial lipids and an associated ceramide-induced inhibition of mitochondrial oxidative phosphorylation and ETC complex activities. Heart failure (HF) was induced by coronary artery ligation. Rats were then randomly assigned to either a normal (10% kcal from fat; HF, n = 8) or high saturated fat diet (60% kcal from saturated fat; HF + Sat, n = 7). Sham-operated animals (sham; n = 8) were fed a normal diet. Eight weeks postligation, left ventricular (LV) function was assessed by echocardiography and catheterization. Subsarcolemmal and interfibrillar mitochondria were isolated from the LV. Heart failure resulted in impaired LV contractile function [decreased percent fractional shortening and peak rate of LV pressure rise and fall (±dP/d t)] and remodeling (increased end-diastolic and end-systolic dimensions) in HF compared with sham. No further progression of LV dysfunction was evident in HF + Sat. Mitochondrial state 3 respiration was increased in HF + Sat compared with HF despite elevated myocardial ceramide. Activities of ETC complexes II and IV were elevated in HF + Sat compared with HF and sham. High saturated fat feeding following coronary artery ligation was associated with increased oxidative phosphorylation and ETC complex activities and did not adversely affect LV contractile function or remodeling, despite elevations in myocardial ceramide.
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Affiliation(s)
- Julie H Rennison
- Dept of Physiology and Biophysics, School of Medicine E558, Case Western Reserve Univ, Cleveland, OH 44106-4970, USA
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Sharma N, Okere IC, Yuan CY, Ernsberger P, Hoit BD, Chandler MP, Stanley WC. High sucrose diet causes increased left ventricular dysfunction and mortality in hypertensive Dahl salt sensitive rats. FASEB J 2007. [DOI: 10.1096/fasebj.21.6.a898-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | - Brian D Hoit
- Physiology & Biophysics
- MedicineCase Western Reserve University10900 Euclid Ave., School of MedicineClevelandOH44108
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Okere IC, Chandler MP, McElfresh TA, Rennison JH, Kung TA, Hoit BD, Ernsberger P, Young ME, Stanley WC. CARNITINE PALMITOYL TRANSFERASE-I INHIBITION IS NOT ASSOCIATED WITH CARDIAC HYPERTROPHY IN RATS FED A HIGH-FAT DIET. Clin Exp Pharmacol Physiol 2007; 34:113-9. [PMID: 17201745 DOI: 10.1111/j.1440-1681.2007.04545.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
1. Cardiac lipotoxicity is characterized by hypertrophy and contractile dysfunction and can be triggered by impaired mitochondrial fatty acid oxidation and lipid accumulation. The present study investigated the effect of dietary fatty acid intake alone and in combination with inhibition of mitochondrial fatty acid uptake with the carnitine palmitoyl transferase (CPT)-I inhibitor oxfenicine. Long-chain fatty acids activate peroxisome proliferator-activated receptors (PPAR), thus mRNA levels of PPAR target genes were measured. 2. Rats were untreated or given the CPT-I inhibitor oxfenicine (150 mg/kg per day) and were fed for 8 weeks with either: (i) standard low-fat chow (10% of energy from fat); (ii) a long-chain saturated fatty acid diet; (iii) a long-chain unsaturated fatty acid diet; or (iv) a medium-chain fatty acid diet (which bypasses CPT-I). High-fat diets contained 60% of energy from fat. 3. Cardiac triglyceride content was increased in the absence of oxfenicine in the saturated fat group compared with other diets. Oxfenicine treatment further increased cardiac triglyceride stores in the saturated fat group and caused a significant increase in the unsaturated fat group. Despite elevations in triglyceride stores, left ventricular mass, end diastolic volume and systolic function were unaffected. 4. The mRNA levels of PPAR-regulated genes were increased by the high saturated and unsaturated fat diets compared with standard chow or the medium chain fatty acid chow. Oxfenicine did not further upregulate PPARalpha target genes within each dietary treatment group. 5. Taken together, the data suggest that consuming a high-fat diet or inhibiting CPT-I do not result in cardiac hypertrophy or cardiac dysfunction in normal rats.
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Affiliation(s)
- Isidore C Okere
- Department of Physiology, Case Western Reserve University, Cleveland, Ohio 44106-4970, USA
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Sharma N, Okere IC, Duda MK, Chess DJ, O'Shea KM, Stanley WC. Potential impact of carbohydrate and fat intake on pathological left ventricular hypertrophy. Cardiovasc Res 2006; 73:257-68. [PMID: 17166490 PMCID: PMC2700717 DOI: 10.1016/j.cardiores.2006.11.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Revised: 11/03/2006] [Accepted: 11/06/2006] [Indexed: 01/11/2023] Open
Abstract
Currently, a high carbohydrate/low fat diet is recommended for patients with hypertension; however, the potentially important role that the composition of dietary fat and carbohydrate plays in hypertension and the development of pathological left ventricular hypertrophy (LVH) has not been well characterized. Recent studies demonstrate that LVH can also be triggered by activation of insulin signaling pathways, altered adipokine levels, or the activity of peroxisome proliferator-activated receptors (PPARs), suggesting that metabolic alterations play a role in the pathophysiology of LVH. Hypertensive patients with high plasma insulin or metabolic syndrome have a greater occurrence of LVH, which could be due to insulin activation of the serine-threonine kinase Akt and its downstream targets in the heart, resulting in cellular hypertrophy. PPARs also activate cardiac gene expression and growth and are stimulated by fatty acids and consumption of a high fat diet. Dietary intake of fats and carbohydrate and the resultant effects of plasma insulin, adipokine, and lipid concentrations may affect cardiomyocyte size and function, particularly in the setting of chronic hypertension. This review discusses potential mechanisms by which dietary carbohydrates and fats ca affect cardiac growth, metabolism, and function, mainly in the context of pressure overload-induced LVH.
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Affiliation(s)
- Naveen Sharma
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
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Okere IC, Young ME, McElfresh TA, Chess DJ, Sharov VG, Sabbah HN, Hoit BD, Ernsberger P, Chandler MP, Stanley WC. Low carbohydrate/high-fat diet attenuates cardiac hypertrophy, remodeling, and altered gene expression in hypertension. Hypertension 2006; 48:1116-23. [PMID: 17060511 DOI: 10.1161/01.hyp.0000248430.26229.0f] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The effects of dietary fat intake on the development of left ventricular hypertrophy and accompanying structural and molecular remodeling in response to hypertension are not understood. The present study compared the effects of a high-fat versus a low-fat diet on development of left ventricular hypertrophy, remodeling, contractile dysfunction, and induction of molecular markers of hypertrophy (ie, expression of mRNA for atrial natriuretic factor and myosin heavy chain beta). Dahl salt-sensitive rats were fed either a low-fat (10% of total energy from fat) or a high-fat (60% of total energy from fat) diet on either low-salt or high-salt (6% NaCl) chow for 12 weeks. Hearts were analyzed for mRNA markers of ventricular remodeling and activities of the mitochondrial enzymes citrate synthase and medium chain acyl-coenzyme A dehydrogenase. Similar levels of hypertension were achieved with high-salt feeding in both diet groups (systolic pressure of approximately 190 mm Hg). In hypertensive rats fed low-fat chow, left ventricular mass, myocyte cross-sectional area, and end-diastolic volume were increased, and ejection fraction was decreased; however, these effects were not observed with the high-fat diet. Hypertensive animals on low-fat chow had increased atrial natriuretic factor mRNA, myosin heavy chain isoform switching (alpha to beta), and decreased activity of citrate synthase and medium chain acyl-coenzyme A dehydrogenase, which were all attenuated by high-fat feeding. In conclusion, increased dietary lipid intake can reduce cardiac growth, left ventricular remodeling, contractile dysfunction, and alterations in gene expression in response to hypertension.
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Affiliation(s)
- Isidore C Okere
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106-4970, USA
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Duda M, Beresewicz A, Sharma N, Okere IC, Chess DJ, Oshea KM, Stanley WC. [Potential impact of carbohydrate and fat intake on cardiac hypertrophy]. Kardiol Pol 2006; 64:S572-S577. [PMID: 20527379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Currently, a high carbohydrate/low fat diet is recommended for patients with heart failure and/or hypertension; however, the potentially important role that the composition of dietary fat and carbohydrate might play in the development of LVH and heart failure has not been well characterized. Recent studies demonstrate that cardiomyocyte hypertrophy can also be triggered by activation of insulin signalling pathways, altered adipokine levels or the activity of peroxisome proliferator-activated receptors (PPARs), suggesting that metabolic alterations play a role in the pathophysiology of LVH and heart failure. Hypertensive patients with high plasma insulin or metabolic syndrome have a greater occurrence of LVH, which could be due to insulin activation of the serine-threonine kinase Akt and its downstream targets in the heart, resulting in cellular hypertrophy. PPARs also activate cardiac gene expression and growth, and are stimulated by fatty acids and consumption of a high fat diet. Dietary intake of fats and carbohydrate, the resultant effects of plasma insulin, adipokine, and lipid concentrations, may affect cardiomyocyte size and function, particularly following cardiac injury or with chronic hypertension. This review discusses potential mechanisms by which dietary carbohydrates and fats can affect cardiac growth, metabolism and function, particularly in the context of pressure overload LVH.
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Affiliation(s)
- Monika Duda
- Department of Physiology, School of Medicine, Case Western Reserve University, Cleveland 44106-4970, USA.
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9
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Duda M, Okere IC, Ernberger P, Chandler MP, Stanley WC. A105. Hypertension decrease serum leptin concentrantion in non-obese rats. J Mol Cell Cardiol 2006. [DOI: 10.1016/j.yjmcc.2006.03.309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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10
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Sharma N, Okere IC, Johnson J, Duda MK, Yuan C, Chandler MP, Stanley WC. A26. Increased LV hypertrophy and mortality in hypertensive Dahl salt sensitive rats fed high fructose diets. J Mol Cell Cardiol 2006. [DOI: 10.1016/j.yjmcc.2006.03.387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Zhou L, Cabrera ME, Okere IC, Sharma N, Stanley WC. Regulation of myocardial substrate metabolism during increased energy expenditure: insights from computational studies. Am J Physiol Heart Circ Physiol 2006; 291:H1036-46. [PMID: 16603683 DOI: 10.1152/ajpheart.01382.2005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In response to exercise, the heart increases its metabolic rate severalfold while maintaining energy species (e.g., ATP, ADP, and Pi) concentrations constant; however, the mechanisms that regulate this response are unclear. Limited experimental studies show that the classic regulatory species NADH and NAD+ are also maintained nearly constant with increased cardiac power generation, but current measurements lump the cytosol and mitochondria and do not provide dynamic information during the early phase of the transition from low to high work states. In the present study, we modified our previously published computational model of cardiac metabolism by incorporating parallel activation of ATP hydrolysis, glycolysis, mitochondrial dehydrogenases, the electron transport chain, and oxidative phosphorylation, and simulated the metabolic responses of the heart to an abrupt increase in energy expenditure. Model simulations showed that myocardial oxygen consumption, pyruvate oxidation, fatty acids oxidation, and ATP generation were all increased with increased energy expenditure, whereas ATP and ADP remained constant. Both cytosolic and mitochondrial NADH/NAD+ increased during the first minutes (by 40% and 20%, respectively) and returned to the resting values by 10-15 min. Furthermore, model simulations showed that an altered substrate selection, induced by either elevated arterial lactate or diabetic conditions, affected cytosolic NADH/NAD+ but had minimal effects on the mitochondrial NADH/NAD+, myocardial oxygen consumption, or ATP production. In conclusion, these results support the concept of parallel activation of metabolic processes generating reducing equivalents during an abrupt increase in cardiac energy expenditure and suggest there is a transient increase in the mitochondrial NADH/NAD+ ratio that is independent of substrate supply.
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Affiliation(s)
- Lufang Zhou
- Department of Biomedical Engineering, Center for Modeling Integrated Metabolic Systems, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106-4970, USA
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Chandler MP, Okere IC, Chess D, Young ME, Ernsberger P, Hoit BD, Stanley WC. High Fat/Low Carbohydrate Feeding Prevents Cardiac Hypertrophy, LV Remodeling and ANF Gene Induction, Independent of Hypertension. FASEB J 2006. [DOI: 10.1096/fasebj.20.5.a1181-d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - M E Young
- PediatricsBaylor College of MedicineOne Baylor PlazaHoustonTX77030
| | | | - B D Hoit
- CardiologyCase Western Reserve University10900 Euclid AveClevelandOH44106
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13
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Duda M, Okere IC, Ernsberger P, Chandler MP, Stanley WC. Decreased Serum Leptin Concentration Independent of Dietary Composition In Hypertensive Non Obese Rats. FASEB J 2006. [DOI: 10.1096/fasebj.20.5.a1183-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Paul Ernsberger
- NutritionCase Western Reserve University10900 Euclid AveClevelandOH44106
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14
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Rennison JH, McElfresh TA, Okere IC, Vazquez EJ, Patel HV, Foster AB, Patel KK, Chen Q, Hoit BD, Hoppel CL, Chandler MP. Post Infarction High Saturated Fat Feeding Does Not Exacerbate LV Dysfunction but Enhances Mitochondrial Function. FASEB J 2006. [DOI: 10.1096/fasebj.20.4.a316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Julie Helene Rennison
- Physiology and BiophysicsCase Western Reserve University10900 Euclid AvenueClevelandOH44106
| | - Tracy A McElfresh
- Physiology and BiophysicsCase Western Reserve University10900 Euclid AvenueClevelandOH44106
| | - Isidore C Okere
- Physiology and BiophysicsCase Western Reserve University10900 Euclid AvenueClevelandOH44106
| | - Edwin J Vazquez
- Veteran Affairs Medical Center10701 East BoulevardClevelandOH44106
| | - Hiral V Patel
- Veteran Affairs Medical Center10701 East BoulevardClevelandOH44106
| | - Amy B Foster
- Veteran Affairs Medical Center10701 East BoulevardClevelandOH44106
| | - Kalpana K Patel
- Veteran Affairs Medical Center10701 East BoulevardClevelandOH44106
| | - Qun Chen
- Veteran Affairs Medical Center10701 East BoulevardClevelandOH44106
| | - Brian D Hoit
- CardiologyUniversity Hospitals11100 Euclid AvenueClevelandOH44106
| | - Charles L Hoppel
- Veteran Affairs Medical Center10701 East BoulevardClevelandOH44106
| | - Margaret P Chandler
- Physiology and BiophysicsCase Western Reserve University10900 Euclid AvenueClevelandOH44106
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Okere IC, Chandler MP, McElfresh TA, Rennison JH, Sharov V, Sabbah HN, Tserng KY, Hoit BD, Ernsberger P, Young ME, Stanley WC. Differential effects of saturated and unsaturated fatty acid diets on cardiomyocyte apoptosis, adipose distribution, and serum leptin. Am J Physiol Heart Circ Physiol 2006; 291:H38-44. [PMID: 16443671 DOI: 10.1152/ajpheart.01295.2005] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Fatty acids are the primary fuel for the heart and are ligands for peroxisome proliferator-activated receptors (PPARs), which regulate the expression of genes encoding proteins involved in fatty acid metabolism. Saturated fatty acids, particularly palmitate, can be converted to the proapoptotic lipid intermediate ceramide. This study assessed cardiac function, expression of PPAR-regulated genes, and cardiomyocyte apoptosis in rats after 8 wk on either a low-fat diet [normal chow control (NC); 10% fat calories] or high-fat diets composed mainly of either saturated (Sat) or unsaturated fatty acids (Unsat) (60% fat calories) (n = 10/group). The Sat group had lower plasma insulin and leptin concentrations compared with the NC or Unsat groups. Cardiac function and mass and body mass were not different. Cardiac triglyceride content was increased in the Sat and Unsat groups compared with NC (P < 0.05); however, ceramide content was higher in the Sat group compared with the Unsat group (2.9 +/- 0.2 vs. 1.4 +/- 0.2 nmol/g; P < 0.05), whereas the NC group was intermediate (2.3 +/- 0.3 nmol/g). The number of apoptotic myocytes, assessed by terminal deoxynucleotide transferase-mediated dUTP nick-end labeling staining, was higher in the Sat group compared with the Unsat group (0.28 +/- 0.05 vs. 0.17 +/- 0.04 apoptotic cells/1,000 nuclei; P < 0.04) and was positively correlated to ceramide content (P < 0.02). Both high-fat diets increased the myocardial mRNA expression of the PPAR-regulated genes encoding uncoupling protein-3 and pyruvate dehydrogenase kinase-4, but only the Sat diet upregulated medium-chain acyl-CoA dehydrogenase. In conclusion, dietary fatty acid composition affects cardiac ceramide accumulation, cardiomyocyte apoptosis, and expression of PPAR-regulated genes independent of cardiac mass or function.
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Affiliation(s)
- Isidore C Okere
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4970, USA
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Okere IC, Chess DJ, McElfresh TA, Johnson J, Rennison J, Ernsberger P, Hoit BD, Chandler MP, Stanley WC. High-fat diet prevents cardiac hypertrophy and improves contractile function in the hypertensive dahl salt-sensitive rat. Clin Exp Pharmacol Physiol 2006; 32:825-31. [PMID: 16173943 DOI: 10.1111/j.1440-1681.2005.04272.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1. The role that dietary lipid and plasma fatty acid concentration play in the development of cardiac hypertrophy in response to hypertension is not clear. 2. In the present study, we treated Dahl salt-sensitive rats with either normal chow (NC), normal chow with salt added (NC + salt) or a diet high in long-chain saturated fatty acids with added salt (HFD + salt). Cardiac function was assessed by echocardiography and left ventricular (LV) catheterization. 3. The HFD + salt group had significantly higher plasma free fatty acid concentrations and myocardial triglyceride content compared with the NC + salt group, but did not upregulate the activity of the fatty acid oxidation enzyme medium chain acyl-coenzyme A dehydrogenase. Systolic blood pressure was elevated to a similar extent in the NC + salt and HFD + salt groups compared with the NC group. Although LV mass was increased in the NC + salt group compared with the NC group, LV mass in the HFD + salt group did not differ from that of the NC group and was significantly lower than that in the NC + salt group. 4. There was no evidence of cardiac dysfunction in the NC + salt group compared with the NC group; however, high fat feeding significantly increased LV contractile performance (e.g. increased cardiac output and peak dP/dt). 5. In conclusion, the HFD + salt diet prevented the hypertrophic response to hypertension and improved the contractile performance of the heart. It remains to be determined whether preventing cardiac hypertrophic adaptations would be deleterious to the heart if the hypertensive stress is maintained long term.
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Affiliation(s)
- Isidore C Okere
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, USA
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Stanley WC, Morgan EE, Huang H, McElfresh TA, Sterk JP, Okere IC, Chandler MP, Cheng J, Dyck JRB, Lopaschuk GD. Malonyl-CoA decarboxylase inhibition suppresses fatty acid oxidation and reduces lactate production during demand-induced ischemia. Am J Physiol Heart Circ Physiol 2005; 289:H2304-9. [PMID: 16100246 DOI: 10.1152/ajpheart.00599.2005] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The rate of cardiac fatty acid oxidation is regulated by the activity of carnitine palmitoyltransferase-I (CPT-I), which is inhibited by malonyl-CoA. We tested the hypothesis that the activity of the enzyme responsible for malonyl-CoA degradation, malonyl-CoA decarboxlyase (MCD), regulates myocardial malonyl-CoA content and the rate of fatty acid oxidation during demand-induced ischemia in vivo. The myocardial content of malonyl-CoA was increased in anesthetized pigs using a specific inhibitor of MCD (CBM-301106), which we hypothesized would result in inhibition of CPT-I, reduction in fatty acid oxidation, a reciprocal activation of glucose oxidation, and diminished lactate production during demand-induced ischemia. Under normal-flow conditions, treatment with the MCD inhibitor significantly reduced oxidation of exogenous fatty acids by 82%, shifted the relationship between arterial fatty acids and fatty acid oxidation downward, and increased glucose oxidation by 50%. Ischemia was induced by a 20% flow reduction and β-adrenergic stimulation, which resulted in myocardial lactate production. During ischemia MCD inhibition elevated malonyl-CoA content fourfold, reduced free fatty acid oxidation rate by 87%, and resulted in a 50% decrease in lactate production. Moreover, fatty acid oxidation during ischemia was inversely related to the tissue malonyl-CoA content ( r = −0.63). There were no differences between groups in myocardial ATP content, the activity of pyruvate dehydrogenase, or myocardial contractile function during ischemia. Thus modulation of MCD activity is an effective means of regulating myocardial fatty acid oxidation under normal and ischemic conditions and reducing lactate production during demand-induced ischemia.
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Affiliation(s)
- William C Stanley
- Dept. of Physiology and Biophysics, School of Medicine, Case Western Reserve Univ., 10900 Euclid Ave., Cleveland, OH 44106-4970, USA.
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Stanley WC, Recchia FA, Okere IC. Metabolic therapies for heart disease: Fish for prevention and treatment of cardiac failure? Cardiovasc Res 2005; 68:175-7. [PMID: 16188244 DOI: 10.1016/j.cardiores.2005.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2005] [Accepted: 09/07/2005] [Indexed: 11/21/2022] Open
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Okere IC, McElfresh TA, Brunengraber DZ, Martini W, Sterk JP, Huang H, Chandler MP, Brunengraber H, Stanley WC. Differential effects of heptanoate and hexanoate on myocardial citric acid cycle intermediates following ischemia-reperfusion. J Appl Physiol (1985) 2005; 100:76-82. [PMID: 16141384 DOI: 10.1152/japplphysiol.00255.2005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the normal heart, there is loss of citric acid cycle (CAC) intermediates that is matched by the entry of intermediates from outside the cycle, a process termed anaplerosis. Previous in vitro studies suggest that supplementation with anaplerotic substrates improves cardiac function during myocardial ischemia and/or reperfusion. The present investigation assessed whether treatment with the anaplerotic medium-chain fatty acid heptanoate improves contractile function during ischemia and reperfusion. The left anterior descending coronary artery of anesthetized pigs was subjected to 60 min of 60% flow reduction and 30 min of reperfusion. Three treatment groups were studied: saline control, heptanoate (0.4 mM), or hexanoate as a negative control (0.4 mM). Treatment was initiated after 30 min of ischemia and continued through reperfusion. Myocardial CAC intermediate content was not affected by ischemia-reperfusion; however, treatment with heptanoate resulted in a more than twofold increase in fumarate and malate, with no change in citrate and succinate, while treatment with hexanoate did not increase fumarate or malate but increased succinate by 1.8-fold. There were no differences among groups in lactate exchange, glucose oxidation, oxygen consumption, and contractile power. In conclusion, despite a significant increase in the content of carbon-4 CAC intermediates, treatment with heptanoate did not result in improved mechanical function of the heart in this model of reversible ischemia-reperfusion. This suggests that reduced anaplerosis and CAC dysfunction do not play a major role in contractile and metabolic derangements observed with a 60% decrease in coronary flow followed by reperfusion.
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Affiliation(s)
- Isidore C Okere
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, Ohio 44106-4970, USA
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King KL, Okere IC, Sharma N, Dyck JRB, Reszko AE, McElfresh TA, Kerner J, Chandler MP, Lopaschuk GD, Stanley WC. Regulation of cardiac malonyl-CoA content and fatty acid oxidation during increased cardiac power. Am J Physiol Heart Circ Physiol 2005; 289:H1033-7. [PMID: 15821035 DOI: 10.1152/ajpheart.00210.2005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myocardial fatty acid oxidation is regulated by carnitine palmitoyltransferase I (CPT I), which is inhibited by malonyl-CoA. Increased cardiac power causes a fall in malonyl-CoA content and accelerated fatty acid oxidation; however, the mechanism for the decrease in malonyl-CoA is unclear. Malonyl-CoA is formed by acetyl-CoA carboxylase (ACC) and degraded by malonyl-CoA decarboxylase (MCD); thus a fall in malonyl-CoA could be due to activation of MCD, inhibition of ACC, or both. This study assessed the effects of increased cardiac power on malonyl-CoA content and ACC and MCD activities. Anesthetized pigs were studied under control conditions and during increased cardiac power in response to dobutamine infusion and aortic constriction alone, under hyperglycemic conditions, or with the CPT I inhibitor oxfenicine. An increase in cardiac power was accompanied by increased myocardial O(2) consumption, decreased malonyl-CoA concentration, and increased fatty acid oxidation. There were no differences among groups in activity of ACC or AMP-activated protein kinase (AMPK), which physiologically inhibits ACC. There also were no differences in V(max) or K(m) of MCD. Previous studies have demonstrated that AMPK can be inhibited by protein kinase B (PKB); however, PKB was activated by dobutamine and the elevated insulin that accompanied hyperglycemia, but there was no effect on AMPK activity. In conclusion, the fall in malonyl-CoA and increase in fatty acid oxidation that occur with increased cardiac work were not due to inhibition of ACC or activation of MCD, suggesting alternative regulatory mechanisms for the work-induced decrease in malonyl-CoA concentration.
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Affiliation(s)
- Kristen L King
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106-4970, USA
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Sharma N, Okere IC, Brunengraber DZ, McElfresh TA, King KL, Sterk JP, Huang H, Chandler MP, Stanley WC. Regulation of pyruvate dehydrogenase activity and citric acid cycle intermediates during high cardiac power generation. J Physiol 2004; 562:593-603. [PMID: 15550462 PMCID: PMC1665507 DOI: 10.1113/jphysiol.2004.075713] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
A high rate of cardiac work increases citric acid cycle (CAC) turnover and flux through pyruvate dehydrogenase (PDH); however, the mechanisms for these effects are poorly understood. We tested the hypotheses that an increase in cardiac energy expenditure: (1) activates PDH and reduces the product/substrate ratios ([NADH]/[NAD(+)] and [acetyl-CoA]/[CoA-SH]); and (2) increases the content of CAC intermediates. Measurements were made in anaesthetized pigs under control conditions and during 15 min of a high cardiac workload induced by dobutamine (Dob). A third group was made hyperglycaemic (14 mm) to stimulate flux through PDH during the high work state (Dob + Glu). Glucose and fatty acid oxidation were measured with (14)C-glucose and (3)H-oleate. Compared with control, the high workload groups had a similar increase in myocardial oxygen consumption ( and cardiac power. Dob increased PDH activity and glucose oxidation above control, but did not reduce the [NADH]/[NAD(+)] and [acetyl-CoA]/[CoA-SH] ratios, and there were no differences between the Dob and Dob + Glu groups. An additional group was treated with Dob + Glu and oxfenicine (Oxf) to inhibit fatty acid oxidation: this increased [CoA-SH] and glucose oxidation compared with Dob; however, there was no further activation of PDH or decrease in the [NADH]/[NAD(+)] ratio. Content of the 4-carbon CAC intermediates succinate, fumarate and malate increased 3-fold with Dob, but there was no change in citrate content, and the Dob + Glu and Dob + Glu + Oxf groups were not different from Dob. In conclusion, compared with normal conditions, at high myocardial energy expenditure (1) the increase in flux through PDH is regulated by activation of the enzyme complex and continues to be partially controlled through inhibition by fatty acid oxidation, and (2) there is expansion of the CAC pool size at the level of 4-carbon intermediates that is largely independent of myocardial fatty acid oxidation.
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Affiliation(s)
- Naveen Sharma
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-4970, USA
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