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Young MJ, Heanue S, Kanki M, Moneghetti KJ. Circadian disruption and its impact on the cardiovascular system. Trends Endocrinol Metab 2024:S1043-2760(24)00316-3. [PMID: 39706759 DOI: 10.1016/j.tem.2024.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Revised: 11/11/2024] [Accepted: 11/25/2024] [Indexed: 12/23/2024]
Abstract
Circadian rhythms are highly conserved biorhythms of ~24 h that govern many fundamental biological processes, including cardiovascular (CV) homeostasis. Disrupting the timing of cellular oscillators promotes cellular stress, and induction of pathogenic pathways underpins the pathogenesis of many CV diseases (CVDs). Thus, shift work, late eating, sleep disturbances, and other disruptors can result in an elevated risk of heart disease and increased incidence of adverse CV events. Here, we discuss the importance of circadian rhythms for CV homeostasis, recent developments in understanding the impact of disrupted circadian rhythms on CV health and disease progression, and how understanding the interactions between circadian and CV physiology is crucial for improving interventions to mitigate CVD, especially in populations impacted by disrupted circadian rhythms.
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Affiliation(s)
- Morag J Young
- Cardiovascular Endocrinology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia; Department of Cardiometabolic Health, University of Melbourne, Melbourne, VIC, Australia.
| | - Seamus Heanue
- Cardiovascular Endocrinology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia; Department of Medicine, Central Clinical School, Monash University, Clayton, VIC, Australia
| | - Monica Kanki
- Cardiovascular Endocrinology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Kegan J Moneghetti
- Cardiovascular Endocrinology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia; Department of Cardiometabolic Health, University of Melbourne, Melbourne, VIC, Australia
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2
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Kadkhodayan A, Lin CH, Coggan AR, Kisrieva-Ware Z, Schechtman KB, Novak E, Joseph SM, Dávila-Román VG, Gropler RJ, Dence C, Peterson LR. Sex affects myocardial blood flow and fatty acid substrate metabolism in humans with nonischemic heart failure. J Nucl Cardiol 2017; 24:1226-1235. [PMID: 27048307 PMCID: PMC5517366 DOI: 10.1007/s12350-016-0467-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 02/25/2016] [Indexed: 01/08/2023]
Abstract
BACKGROUND In animal models of heart failure (HF), myocardial metabolism shifts from high-energy fatty acid (FA) metabolism toward glucose. However, FA (vs glucose) metabolism generates more ATP/mole; thus, FA metabolism may be especially advantageous in HF. Sex modulates myocardial blood flow (MBF) and substrate metabolism in normal humans. Whether sex affects MBF and metabolism in patients with HF is unknown. METHODS AND RESULTS We studied 19 well-matched men and women with nonischemic HF (EF ≤ 35%). MBF and myocardial substrate metabolism were quantified using positron emission tomography. Women had higher MBF (mL/g/minute), FA uptake (mL/g/minute), and FA utilization (nmol/g/minute) (P < 0.005, P < 0.005, P < 0.05, respectively) and trended toward having higher FA oxidation than men (P = 0.09). These findings were independent of age, obesity, and insulin resistance. There were no sex-related differences in fasting myocardial glucose uptake or metabolism. Higher MBF was related to improved event-free survival (HR 0.31, P = 0.02). CONCLUSIONS In nonischemic HF, women have higher MBF and FA uptake and metabolism than men, irrespective of age, obesity, or insulin resistance. Moreover, higher MBF portends a better prognosis. These sex-related differences should be taken into account in the development and targeting of novel agents aimed at modulating MBF and metabolism in HF.
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Affiliation(s)
- Ana Kadkhodayan
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Cardiovascular Division, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - C Huie Lin
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, Campus Box 8086, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
- Debakey Cardiovascular Associates, Houston Methodist Hospital, Houston, USA
| | - Andrew R Coggan
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Zulfia Kisrieva-Ware
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Kenneth B Schechtman
- Division of Biostatistics, Washington University School of Medicine, St. Louis, MO, USA
| | - Eric Novak
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, Campus Box 8086, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Susan M Joseph
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, Campus Box 8086, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Víctor G Dávila-Román
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, Campus Box 8086, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Robert J Gropler
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Carmen Dence
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Linda R Peterson
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, Campus Box 8086, 660 S. Euclid Ave, St. Louis, MO, 63110, USA.
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Fang L, Zhou J, Cheng S, Ying J, Yang Z, Yin L, Li S, Hou W, Wang Z. High orexin-A neuron activity and RACK1 expression might be involved in the restricted feeding-entrained behaviors in mice. BIOL RHYTHM RES 2015. [DOI: 10.1080/09291016.2015.1004841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Hou W, Xiong L, Li S, Wang Y, Jiang Z, Cheng S, Liu Y, Xiao J, Guo H, Wang Z. A continuous electromagnetic radiation exposure affected the expressions ofClockandfviigenes in mice. BIOL RHYTHM RES 2013. [DOI: 10.1080/09291016.2013.770295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ko ML, Shi L, Tsai JY, Young ME, Neuendorff N, Earnest DJ, Ko GYP. Cardiac-specific mutation of Clock alters the quantitative measurements of physical activities without changing behavioral circadian rhythms. J Biol Rhythms 2011; 26:412-22. [PMID: 21921295 PMCID: PMC3181102 DOI: 10.1177/0748730411414170] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Even though peripheral circadian oscillators in the cardiovascular system are known to exist, the daily rhythms of the cardiovascular system are mainly attributed to autonomic or hormonal inputs under the control of the central oscillator, the suprachiasmatic nucleus (SCN). In order to examine the role of peripheral oscillators in the cardiovascular system, we used a transgenic mouse where the Clock gene is specifically disrupted in cardiomyocytes. In this cardiomyocyte-specific CLOCK mutant (CCM) mouse model, the circadian input from the SCN remains intact. Both CCM and wild-type (WT) littermates displayed circadian rhythms in wheel-running behavior. However, the overall wheel-running activities were significantly lower in CCM mice compared to WT over the course of 5 weeks, indicating that CCM mice either have lower baseline physical activities or they have lower physical adaptation abilities because daily wheel running, like routine exercise, induces physical adaptation over a period of time. Upon further biochemical analysis, it was revealed that the diurnal oscillations of phosphorylation states of several kinases and protein expression of the L-type voltage-gated calcium channel (L-VGCC) α1D subunit found in WT hearts were abolished in CCM hearts, indicating that in mammalian hearts, the daily oscillations of the activities of these kinases and L-VGCCs were downstream elements of the cardiac core oscillators. However, the phosphorylation of p38 MAPK exhibited robust diurnal rhythms in both WT and CCM hearts, indicating that cardiac p38 could be under the influence of the central clock through neurohormonal signals or be part of the circadian input pathway in cardiomyocytes. Taken together, these results indicate that the cardiac core oscillators have an impact in regulating circadian rhythmicities and cardiac function.
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Affiliation(s)
- Michael L. Ko
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
| | - Liheng Shi
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
| | - Ju-Yun Tsai
- US Department of Agriculture/Agricultural Research Service Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX
| | - Martin E. Young
- Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL
| | - Nichole Neuendorff
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College Station, TX
| | - David J. Earnest
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College Station, TX
| | - Gladys Y.-P. Ko
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
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Bossone E, Citro R, Eagle KA, Manfredini R. Tako-tsubo cardiomyopathy: is there a preferred time of onset? Intern Emerg Med 2011; 6:221-6. [PMID: 21082291 DOI: 10.1007/s11739-010-0480-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 10/29/2010] [Indexed: 12/30/2022]
Abstract
The occurrence of major cardiovascular events is not randomly distributed over time, but exhibits chronobiological patterns, i.e., circadian, weekly, or seasonal. No systematic studies on the temporal preference of onset of Tako-tsubo cardiomyopathy (TTC) are known. We performed a computer-assisted search of the literature (from 2000 to January 2010), with the following search terms: transient left ventricular apical ballooning syndrome, takotsubo-like left ventricular dysfunction, ampulla cardiomyopathy, tako-tsubo or takotsubo cardiomyopathy, tako-tsubo, apical ballooning. Criteria for publication inclusion were (a) reporting of original data, (b) inclusion of at least 30 or more cases, (c) adherence to the requested diagnostic criteria for TTC. We focused on studies including in their purposes the "time of onset" of events. Out of the 19 studies found, 7 (4 from Europe, 1 each from Asia, Australia and USA) specifically addressed this aspect. A circadian (morning) and a seasonal (summer) higher frequency of events was found. TTC seems to exhibit a temporal variation of onset, with preferred peaks during morning and summer. Stress and catecholamines, also according to their temporal organization, might play a pivotal role. The demonstration of time frames characterized by highest frequency of occurrence might help to try to ensure maximal protection during particularly vulnerable periods.
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Affiliation(s)
- Eduardo Bossone
- Department of Cardiac Surgery, I.R.C.C.S. Policlinico San Donato, San Donato Milanese, Milan, Italy.
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Ko ML, Shi L, Grushin K, Nigussie F, Ko GYP. Circadian profiles in the embryonic chick heart: L-type voltage-gated calcium channels and signaling pathways. Chronobiol Int 2011; 27:1673-96. [PMID: 20969517 DOI: 10.3109/07420528.2010.514631] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Circadian clocks exist in the heart tissue and modulate multiple physiological events, from cardiac metabolism to contractile function and expression of circadian oscillator and metabolic-related genes. Ample evidence has demonstrated that there are endogenous circadian oscillators in adult mammalian cardiomyocytes. However, mammalian embryos cannot be entrained independently to light-dark (LD) cycles in vivo without any maternal influence, but circadian genes are well expressed and able to oscillate in embryonic stages. The authors took advantage of using chick embryos that are independent of maternal influences to investigate whether embryonic hearts could be entrained under LD cycles in ovo. The authors found circadian regulation of L-type voltage-gated calcium channels (L-VGCCs), the ion channels responsible for the production of cardiac muscle contraction in embryonic chick hearts. The mRNA levels and protein expression of VGCCα1C and VGCCα1D are under circadian control, and the average L-VGCC current density is significantly larger when cardiomyocytes are recorded during the night than day. The phosphorylation states of several kinases involved in insulin signaling and cardiac metabolism, including extracellular signal-regulated kinase (Erk), stress-activated protein kinase (p38), protein kinase B (Akt), and glycogen synthase kinase-3β (GSK-3β), are also under circadian control. Both Erk and p38 have been implicated in regulating cardiac contractility and in the development of various pathological states, such as cardiac hypertrophy and heart failure. Even though both Erk and phosphoinositide 3-kinase (PI3K)-Akt signaling pathways participate in complex cellular processes regarding physiological or pathological states of cardiomyocytes, the circadian oscillators in the heart regulate these pathways independently, and both pathways contribute to the circadian regulation of L-VGCCs.
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Affiliation(s)
- Michael L Ko
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
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Collins HE, Rodrigo GC. Inotropic response of cardiac ventricular myocytes to beta-adrenergic stimulation with isoproterenol exhibits diurnal variation: involvement of nitric oxide. Circ Res 2010; 106:1244-52. [PMID: 20167926 DOI: 10.1161/circresaha.109.213942] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
RATIONALE Although >10% of cardiac gene expression displays diurnal variations, little is known of their impact on excitation-contraction coupling. OBJECTIVE To determine whether the time of day affects excitation-contraction coupling in rat ventricles. METHODS AND RESULTS Left ventricular myocytes were isolated from rat hearts at 2 opposing time points, corresponding to the animals resting or active periods. Basal contraction and [Ca(2+)](i) was significantly greater in myocytes isolated during the resting versus active periods (cell shortening 12.4+/-0.3 versus 11.0+/-0.2%; P<0.05 and systolic [Ca(2+)](i) 422+/-12 versus 341+/-9 nmol/L; P<0.01. This corresponded to a greater sarcoplasmic reticulum (SR) Ca(2+) load (672+/-20 versus 551+/-13 nmol/L P<0.001). The increase in systolic [Ca(2+)](i) in response to isoproterenol (>3 nmol/L) was also significantly greater in resting versus active period myocytes, reflecting a greater SR Ca(2+) load at this time. This diurnal variation in response of Ca(2+)-homeostasis to isoproterenol translated to a greater incidence of arrhythmic activity in resting period myocytes. Inhibition of neuronal NO synthase during stimulation with isoproterenol, further increased systolic [Ca(2+)](i) and the percentage of arrhythmic myocytes, but this effect was significantly greater in active period versus resting period myocytes. Quantitative RT-PCR analysis revealed a 2.65-fold increase in neuronal NO synthase mRNA levels in active over resting period myocytes (P<0.05). CONCLUSIONS The threshold for the development of arrhythmic activity in response to isoproterenol is higher during the active period of the rat. We suggest this reflects a reduction in SR Ca(2+) loading and a diurnal variation in neuronal NO synthase signaling.
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MESH Headings
- Adrenergic beta-Agonists/adverse effects
- Adrenergic beta-Agonists/pharmacology
- Animals
- Arrhythmias, Cardiac/chemically induced
- Arrhythmias, Cardiac/metabolism
- Calcium/metabolism
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/metabolism
- Calcium Signaling/drug effects
- Cardiac Pacing, Artificial
- Circadian Rhythm
- Dose-Response Relationship, Drug
- Excitation Contraction Coupling/drug effects
- Gene Expression Regulation, Enzymologic/drug effects
- Heart Ventricles/drug effects
- Heart Ventricles/metabolism
- Homeostasis
- Isoproterenol/adverse effects
- Isoproterenol/pharmacology
- Male
- Myocardial Contraction/drug effects
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Nitric Oxide/metabolism
- Nitric Oxide Synthase/genetics
- Nitric Oxide Synthase/metabolism
- Nitric Oxide Synthase Type I
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Sarcoplasmic Reticulum/drug effects
- Sarcoplasmic Reticulum/metabolism
- Up-Regulation
- Ventricular Function, Left/drug effects
- Ventricular Pressure/drug effects
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Affiliation(s)
- Helen E Collins
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester LE3 9QP, United Kingdom
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9
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Abstract
Diurnal rhythms influence cardiovascular physiology such as heart rate and blood pressure and the incidence of adverse cardiac events such as heart attack and stroke. For example, shift workers and patients with sleep disturbances, such as obstructive sleep apnea, have an increased risk of heart attack, stroke, and sudden death. Diurnal variation is also evident at the molecular level, as gene expression in the heart and blood vessels is remarkably different in the day as compared to the night. Much of the evidence presented here indicates that growth and renewal (structural remodeling) are highly dependent on processes that occur during the subjective night. Myocardial metabolism is also dynamic with substrate preference also differing day from night. The risk/benefit ratio of some therapeutic strategies and the appearance of biomarkers also vary across the 24-hour diurnal cycle. Synchrony between external and internal diurnal rhythms and harmony among the molecular rhythms within the cell is essential for normal organ biology. Cell physiology is 4 dimensional; the substrate and enzymatic components of a given metabolic pathway must be present not only in the right compartmental space within the cell but also at the right time. As a corollary, we show disrupting this integral relationship has devastating effects on cardiovascular, renal and possibly other organ systems. Harmony between our biology and our environment is vital to good health.
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Affiliation(s)
- Tami A Martino
- Department of Biomedical Sciences, OVC, University of Guelph, Guelph, ON, Canada, N1G2W1.
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10
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Zungu M, Young ME, Stanley WC, Essop MF. Chronic treatment with the peroxisome proliferator-activated receptor alpha agonist Wy-14,643 attenuates myocardial respiratory capacity and contractile function. Mol Cell Biochem 2009; 330:55-62. [PMID: 19360380 DOI: 10.1007/s11010-009-0100-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 03/30/2009] [Indexed: 12/24/2022]
Abstract
We investigated whether chronic in vivo treatment with the peroxisome proliferator-activated receptor alpha agonist Wy-14,643 attenuates cardiac contractile function by impairing mitochondrial respiration. Wy-14,643 (25 mg kg(-1) day(-1)) was administered to Wistar rats by oral gavage for 14 consecutive days, after which ex vivo heart function, myocardial mitochondrial respiratory capacity, and metabolic gene expression were determined. Body and heart weights were not significantly altered following 14 days of Wy-14,643 administration. Heart perfusion studies showed significantly reduced systolic and developed pressures, while the rate pressure product declined by 36 +/- 2.6% (P < 0.01 vs. vehicle) after 14 days of Wy-14,643 treatment. State 3 mitochondrial respiration was lower in the Wy-14,643 group (P = 0.06 vs. vehicle). State 4 respiration and oligomycin-insensitive proton leak were significantly increased compared with matched controls. The rate of ADP phosphorylation was also decreased by 44.9 +/- 1.9% (P < 0.05 vs. vehicle). Pyruvate dehydrogenase kinase 4 (PDK4) and uncoupling protein 3 (UCP3) transcript levels were upregulated, while cytochrome oxidase II (COXII) expression was decreased following Wy-14,643 treatment. This study demonstrates that chronic in vivo Wy-14,643 administration impaired cardiac contractile function in parallel with decreased mitochondrial respiratory function and increased uncoupling.
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Affiliation(s)
- Makhosazane Zungu
- Hatter Heart Research Institute, Department of Medicine, University of Cape Town Faculty of Health Sciences, Cape Town, South Africa
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Zungu M, Young ME, Stanley WC, Essop MF. Expression of mitochondrial regulatory genes parallels respiratory capacity and contractile function in a rat model of hypoxia-induced right ventricular hypertrophy. Mol Cell Biochem 2008; 318:175-81. [PMID: 18604475 DOI: 10.1007/s11010-008-9867-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Accepted: 06/25/2008] [Indexed: 10/21/2022]
Abstract
Chronic hypobaric hypoxia (CHH) increases load on the right ventricle (RV) resulting in RV hypertrophy. We hypothesized that CHH elicits distinct responses, i.e., the hypertrophied RV, unlike the left ventricle (LV), displaying enhanced mitochondrial respiratory and contractile function. Wistar rats were exposed to 4 weeks CHH (11% O(2)) versus normoxic controls. RV/body weight ratio increased (P < 0.001 vs. control) while RV systolic and developed pressures were higher. However, LV systolic and developed pressures were significantly reduced. Mitochondrial O(2) consumption was sustained in the hypertrophied RV, ADP/O increased (P < 0.01 vs. control) and proton leak significantly decreased. Conversely, LV mitochondrial O(2) consumption was attenuated (P < 0.05 vs. control) and proton leak significantly increased. In parallel, expression of mitochondrial regulators was upregulated in the hypertrophied RV but not the LV. Our data show that the hypertrophied RV induces expression of mitochondrial regulatory genes linking respiratory capacity and enhanced efficiency to sustained contractile function.
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Affiliation(s)
- Makhosazane Zungu
- Hatter Heart Research Institute, Department of Medicine, University of Cape Town Faculty of Health Sciences, Cape Town, South Africa
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12
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Zungu M, Alcolea MP, García-Palmer FJ, Young ME, Essop MF. Genomic modulation of mitochondrial respiratory genes in the hypertrophied heart reflects adaptive changes in mitochondrial and contractile function. Am J Physiol Heart Circ Physiol 2007; 293:H2819-25. [PMID: 17704287 DOI: 10.1152/ajpheart.00806.2006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We hypothesized the coordinate induction of mitochondrial regulatory genes in the hypertrophied right ventricle to sustain mitochondrial respiratory capacity and contractile function in response to increased load. Wistar rats were exposed to hypobaric hypoxia (11% O2) or normoxia for 2 wk. Cardiac contractile and mitochondrial respiratory function were separately assessed for the right and left ventricles. Transcript levels of several mitochondrial regulators were measured. A robust hypertrophic response was observed in the right (but not left) ventricle in response to hypobaric hypoxia. Mitochondrial O2consumption was increased in the right ventricle, while proton leak was reduced vs. normoxic controls. Citrate synthase activity and mitochondrial DNA content were significantly increased in the hypertrophied right ventricle, suggesting higher mitochondrial number. Transcript levels of nuclear respiratory factor-1, peroxisome proliferator-activated receptor-γ-coactivator-1α, cytochrome oxidase (COX) subunit II, and uncoupling protein-2 (UCP2) were coordinately induced in the hypertrophied right ventricle following hypoxia. UCP3 transcript levels were significantly reduced in the hypertrophied right ventricle vs. normoxic controls. Exposure to chronic hypobaric hypoxia had no significant effects on left ventricular mitochondrial respiration or contractile function. However, COXIV and UCP2 gene expression were increased in the left ventricle in response to chronic hypobaric hypoxia. In summary, we found coordinate induction of several genes regulating mitochondrial function and higher mitochondrial number in a model of physiological right ventricular hypertrophy, linking the efficiency of mitochondrial oxidative phosphorylation and respiratory function to sustained contractile function in response to the increased load.
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Affiliation(s)
- Makhosazane Zungu
- Hatter Heart Research Institute, Department of Medicine, University of Cape Town Faculty of Health Sciences, Cape Town, South Africa
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13
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Durgan DJ, Moore MWS, Ha NP, Egbejimi O, Fields A, Mbawuike U, Egbejimi A, Shaw CA, Bray MS, Nannegari V, Hickson-Bick DL, Heird WC, Dyck JRB, Chandler MP, Young ME. Circadian rhythms in myocardial metabolism and contractile function: influence of workload and oleate. Am J Physiol Heart Circ Physiol 2007; 293:H2385-93. [PMID: 17616739 DOI: 10.1152/ajpheart.01361.2006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Multiple extracardiac stimuli, such as workload and circulating nutrients (e.g., fatty acids), known to influence myocardial metabolism and contractile function exhibit marked circadian rhythms. The aim of the present study was to investigate whether the rat heart exhibits circadian rhythms in its responsiveness to changes in workload and/or fatty acid (oleate) availability. Thus, hearts were isolated from male Wistar rats (housed during a 12:12-h light-dark cycle: lights on at 9 AM) at 9 AM, 3 PM, 9 PM, and 3 AM and perfused in the working mode ex vivo with 5 mM glucose plus either 0.4 or 0.8 mM oleate. Following 20-min perfusion at normal workload (i.e., 100 cm H(2)O afterload), hearts were challenged with increased workload (140 cm H(2)O afterload plus 1 microM epinephrine). In the presence of 0.4 mM oleate, myocardial metabolism exhibited a marked circadian rhythm, with decreased rates of glucose oxidation, increased rates of lactate release, decreased glycogenolysis capacity, and increased channeling of oleate into nonoxidative pathways during the light phase. Rat hearts also exhibited a modest circadian rhythm in responsiveness to the workload challenge when perfused in the presence of 0.4 mM oleate, with increased myocardial oxygen consumption at the dark-to-light phase transition. However, rat hearts perfused in the presence of 0.8 mM oleate exhibited a markedly blunted contractile function response to the workload challenge during the light phase. In conclusion, these studies expose marked circadian rhythmicities in myocardial oxidative and nonoxidative metabolism as well as responsiveness of the rat heart to changes in workload and fatty acid availability.
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Affiliation(s)
- David J Durgan
- United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Houston, Texas, USA
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14
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Martino TA, Tata N, Bjarnason GA, Straume M, Sole MJ. Diurnal protein expression in blood revealed by high throughput mass spectrometry proteomics and implications for translational medicine and body time of day. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1430-7. [PMID: 17553849 DOI: 10.1152/ajpregu.00183.2007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Molecular gene cycling is useful for determining body time of day (BTOD) with important applications in personalized medicine, including cardiovascular disease and cancer, our leading causes of death. However, it impractically requires repetitive invasive tissue sampling that is obviously not applicable for humans. Here we characterize diurnal protein cycling in blood using high-throughput proteomics; blood proteins are easily accessible, minimally invasive, and can importantly serve as surrogates for what is happening elsewhere in the body in health and disease. As proof of the concept, we used normal C57BL/6 mice maintained under regular 24-h light and dark cycles. First, we demonstrated fingerprint patterns in 24-h plasma, revealed using surface-enhanced laser desorption and ionization (SELDI). Second, we characterized diurnal cycling proteins in blood using chromatography and tandem electrospray ionization mass spectrometry. Importantly, we noted little association between the cycling blood proteome and tissue transcriptome, delineating the necessity to identify de novo cycling proteins in blood for measuring BTOD. Furthermore, we explored known interaction networks to identify putative functional pathways regulating protein expression patterns in blood, thus shedding new light on our understanding of integrative physiology. These studies have profound clinical significance in translating the concept of BTOD to the practical realm for molecular diagnostics and open new opportunities for clinically relevant discoveries when applied to ELISA-based molecular testing and/or point-of-care devices.
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Affiliation(s)
- Tami A Martino
- University Health Network, 4N-488 Toronto General Hospital, 585 University Avenue, Toronto, Ontario, Canada.
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15
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Waterhouse J, Atkinson G, Reilly T, Jones H, Edwards B. Chronophysiology of the cardiovascular system. BIOL RHYTHM RES 2007. [DOI: 10.1080/09291010600906109] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Murphy E, Steenbergen C. Inhibition of GSK-3beta as a target for cardioprotection: the importance of timing, location, duration and degree of inhibition. Expert Opin Ther Targets 2007; 9:447-56. [PMID: 15948666 DOI: 10.1517/14728222.9.3.447] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cardiovascular disease is the major cause of morbidity and mortality in western countries such as the US. Myocardial infarction leads to loss of myocytes and with extremely limited ability to replenish cardiomyocytes, the heart exhibits depressed contractility. This ultimately results in hypertrophy of the remaining viable myocytes, which is the primary predictor for heart failure. Thus, drug therapies which can reduce myocyte cell death and reduce postischaemic dysfunction would be expected to greatly reduce cardiac hypertrophy and subsequent heart failure and death. Inhibition of glycogen synthase kinase (GSK)-3beta has been proposed as a strategy to improve postischaemic cardiomyocyte survival, as inhibition of GSK-3beta has been shown to reduce myocardial cell death following ischaemia and reperfusion. Therapies for inhibiting GSK are feasible as there are a number of newly developed specific inhibitors of GSK available, although most of these drugs have not been tested in long-term animal studies.
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Affiliation(s)
- Elizabeth Murphy
- National Institute of Environmental Health Sciences, Laboratory of Signal Transduction, NIH, DHHS, Research Triangle Park, NC 27709, USA.
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17
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Kupper N, Willemsen G, Boomsma DI, de Geus EJC. Heritability of indices for cardiac contractility in ambulatory recordings. J Cardiovasc Electrophysiol 2006; 17:877-83. [PMID: 16800859 DOI: 10.1111/j.1540-8167.2006.00535.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Overactivity of the sympathetic nervous system (SNS) plays a pivotal role in the development of cardiovascular disease. This involvement suggests that the genetic susceptibility to adverse cardiovascular events may derive in part from individual differences in SNS activity. METHODS AND RESULTS To establish a genetic contribution to SNS activity, we measured sympathetic effects on cardiac contractility in 755 healthy adult twins and their singleton siblings. The preejection period (PEP) and the ratio of PEP to the left ventricular ejection time (PEP/LVET ratio) were derived from ambulatory recordings of the ECG and thorax impedance. During this type of prolonged recordings in a real life setting, the extent of cardiac sympathetic activity will vary with the demands of daily activities. Therefore, the genetic architecture of both indices was examined separately across three daytime periods (morning, afternoon, evening), and during nighttime sleep. Results showed significant genetic contribution to PEP (48-62%) over all daily periods. Heritability estimates for PEP/LVET ratio ranged between 35% and 58%. Cardiac sympathetic activity during the waking and sleep periods was largely influenced by genetic factors that were common to the entire 24-hour period. During sleep, additional genetic influences emerged that accounted for 8% of the variance in PEP. CONCLUSION Impedance-derived measures of sympathetic effects on cardiac contractility show substantial heritability across all periods of the day and during sleep.
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Affiliation(s)
- Nina Kupper
- Department of Biological Psychology, Vrije Universiteit, Van der Boechorststraat, Amsterdam, The Netherlands
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18
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Durgan DJ, Trexler NA, Egbejimi O, McElfresh TA, Suk HY, Petterson LE, Shaw CA, Hardin PE, Bray MS, Chandler MP, Chow CW, Young ME. The circadian clock within the cardiomyocyte is essential for responsiveness of the heart to fatty acids. J Biol Chem 2006; 281:24254-69. [PMID: 16798731 DOI: 10.1074/jbc.m601704200] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cells/organs must respond both rapidly and appropriately to increased fatty acid availability; failure to do so is associated with the development of skeletal muscle and hepatic insulin resistance, pancreatic beta-cell dysfunction, and myocardial contractile dysfunction. Here we tested the hypothesis that the intrinsic circadian clock within the cardiomyocytes of the heart allows rapid and appropriate adaptation of this organ to fatty acids by investigating the following: 1) whether circadian rhythms in fatty acid responsiveness persist in isolated adult rat cardiomyocytes, and 2) whether manipulation of the circadian clock within the heart, either through light/dark (L/D) cycle or genetic disruptions, impairs responsiveness of the heart to fasting in vivo. We report that both the intramyocellular circadian clock and diurnal variations in fatty acid responsiveness observed in the intact rat heart in vivo persist in adult rat cardiomyocytes. Reversal of the 12-h/12-h L/D cycle was associated with a re-entrainment of the circadian clock within the rat heart, which required 5-8 days for completion. Fasting rats resulted in the induction of fatty acid-responsive genes, an effect that was dramatically attenuated 2 days after L/D cycle reversal. Similarly, a targeted disruption of the circadian clock within the heart, through overexpression of a dominant negative CLOCK mutant, severely attenuated induction of myocardial fatty acid-responsive genes during fasting. These studies expose a causal relationship between the circadian clock within the cardiomyocyte with responsiveness of the heart to fatty acids and myocardial triglyceride metabolism.
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Affiliation(s)
- David J Durgan
- United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
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19
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Young ME. The circadian clock within the heart: potential influence on myocardial gene expression, metabolism, and function. Am J Physiol Heart Circ Physiol 2006; 290:H1-16. [PMID: 16373589 DOI: 10.1152/ajpheart.00582.2005] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
It is becoming increasingly clear that the intrinsic properties of both the heart and vasculature exhibit dramatic oscillations over the course of the day. Diurnal variations in the responsiveness of the cardiovascular system to environmental stimuli are mediated by a complex interplay between extracellular (i.e., neurohumoral factors) and intracellular (i.e., circadian clock) influences. The intracellular circadian clock is composed of a series of transcriptional modulators that together allow the cell to perceive the time of day, thereby enabling preparation for an anticipated stimulus. These molecular timepieces have been characterized recently within both vascular smooth muscle cells and cardiomyocytes, giving rise to a multitude of hypotheses relating to the potential role(s) of the circadian clock as a modulator of physiological and pathophysiological cardiovascular events. For example, evidence strongly supports the hypothesis that the circadian clock within the heart modulates myocardial metabolism, which in turn facilitates anticipation of diurnal variations in workload, substrate availability, and/or the energy supply-to-demand ratio. The purpose of this review is therefore to summarize our current understanding of the molecular events governing diurnal variations in the intrinsic properties of the heart, with special emphasis on the intramyocardial circadian clock. Whether impairment of this molecular mechanism contributes toward cardiovascular disease associated with hypertension, diabetes mellitus, shift work, sleep apnea, and/or obesity will be discussed.
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Affiliation(s)
- Martin E Young
- United States Dept. of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Dept. of Pediatrics, Baylor College of Medicine, 1100 Bates St., Houston, TX 77030, USA.
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Durgan DJ, Hotze MA, Tomlin TM, Egbejimi O, Graveleau C, Abel ED, Shaw CA, Bray MS, Hardin PE, Young ME. The intrinsic circadian clock within the cardiomyocyte. Am J Physiol Heart Circ Physiol 2005; 289:H1530-41. [PMID: 15937094 DOI: 10.1152/ajpheart.00406.2005] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Circadian clocks are intracellular molecular mechanisms that allow the cell to anticipate the time of day. We have previously reported that the intact rat heart expresses the major components of the circadian clock, of which its rhythmic expression in vivo is consistent with the operation of a fully functional clock mechanism. The present study exposes oscillations of circadian clock genes [brain and arylhydrocarbon receptor nuclear translocator-like protein 1 ( bmal1), reverse strand of the c-erbaα gene ( rev-erbaα), period 2 ( per2), albumin D-element binding protein ( dbp)] for isolated adult rat cardiomyocytes in culture. Acute (2 h) and/or chronic (continuous) treatment of cardiomyocytes with FCS (50% and 2.5%, respectively) results in rhythmic expression of circadian clock genes with periodicities of 20–24 h. In contrast, cardiomyocytes cultured in the absence of serum exhibit dramatically dampened oscillations in bmal1 and dbp only. Zeitgebers (timekeepers) are factors that influence the timing of the circadian clock. Glucose, which has been previously shown to reactivate circadian clock gene oscillations in fibroblasts, has no effect on the expression of circadian clock genes in adult rat cardiomyocytes, either in the absence or presence of serum. Exposure of adult rat cardiomyocytes to the sympathetic neurotransmitter norephinephrine (10 μM) for 2 h reinitiates rhythmic expression of circadian clock genes in a serum-independent manner. Oscillations in circadian clock genes were associated with 24-h oscillations in the metabolic genes pyruvate dehydrogenase kinase 4 ( pdk4) and uncoupling protein 3 ( ucp3). In conclusion, these data suggest that the circadian clock operates within the myocytes of the heart and that this molecular mechanism persists under standard cell culture conditions (i.e., 2.5% serum). Furthermore, our data suggest that norepinephrine, unlike glucose, influences the timing of the circadian clock within the heart and that the circadian clock may be a novel mechanism regulating myocardial metabolism.
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Affiliation(s)
- David J Durgan
- Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Ctr. at Houston, 2121 W. Holcombe Blvd., IBT 1011, Houston, TX 77030, USA
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21
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Claustrat F, Fournier I, Geelen G, Brun J, Corman B, Claustrat B. [Aging and circadian clock gene expression in peripheral tissues in rats]. ACTA ACUST UNITED AC 2005; 53:257-60. [PMID: 15939133 DOI: 10.1016/j.patbio.2004.12.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Accepted: 12/13/2004] [Indexed: 10/25/2022]
Abstract
Aging is associated with alterations of the circadian rhythms (shortened amplitude and phase-advance). We studied by quantitative RT-PCR the influence of aging on the expression of circadian clock genes (Clock, Bmal1, Cry1,2, Per1-3) in peripheral tissues (liver and heart) of middle-aged (13 months) and old (27 months) rats of the Wag/Rij strain exposed to a 12 hours light/12 hours dark cycle. Rats were killed at the light-dark transition (8 am and 8 pm). In the liver, Per, Cry et Bmal1 genes showed a morning/evening difference of expression; in addition, old rats exhibited a significant decrease of Per gene expression in the evening vs middle-aged rats. The heart showed similar profiles with only a tendency toward a decrease of Per expression and an increased Bmal1 expression in the evening in old rats. These results show that aging is associated with circadian gene expression changes.
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Affiliation(s)
- F Claustrat
- Service de radioanalyse, hôpital cardiologique, 59, boulevard Pinel, 69677 Bron cedex, France.
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Stavinoha MA, Rayspellicy JW, Hart-Sailors ML, Mersmann HJ, Bray MS, Young ME. Diurnal variations in the responsiveness of cardiac and skeletal muscle to fatty acids. Am J Physiol Endocrinol Metab 2004; 287:E878-87. [PMID: 15292029 DOI: 10.1152/ajpendo.00189.2004] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac and skeletal muscle both respond to elevated fatty acid availability by increasing fatty acid oxidation, an effect mediated in large part by peroxisome proliferator-activated receptor-alpha (PPAR alpha). We hypothesized that cardiac and skeletal muscle alter their responsiveness to fatty acids over the course of the day, allowing optimal adaptation when availability of this substrate increases. In the current study, pyruvate dehydrogenase kinase 4 (pdk4) was utilized as a representative PPAR alpha-regulated gene. Opposing diurnal variations in pdk4 expression were observed in cardiac and skeletal muscle isolated from the ad libitum-fed rat; pdk4 expression peaked in the middle of the dark and light phases, respectively. Elevation of circulating fatty acid levels by high-fat feeding, fasting, and streptozotocin-induced diabetes increased pdk4 expression in both heart and soleus muscle. Highest levels of induction were observed during the dark phase, regardless of muscle type or intervention. Specific activation of PPAR alpha with WY-14643 rapidly induced pdk4 expression in heart and soleus muscle. Highest levels of induction were again observed during the dark phase. The same pattern of induction was observed for the PPAR alpha-regulated genes malonyl-CoA decarboxylase and uncoupling protein 3. Investigation into the potential mechanism(s) for these observations exposed a coordinated upregulation of transcriptional activators of the PPAR alpha system during the night, with a concomitant downregulation of transcriptional repressors in both muscle types. In conclusion, responsiveness of cardiac and skeletal muscle to fatty acids exhibits a marked diurnal variation. These observations have important physiological and pathophysiological implications, ranging from experimental design to pharmacological treatment of patients.
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Affiliation(s)
- Melissa A Stavinoha
- Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 2121 W. Holcombe Blvd., IBT 1011B, Houston, TX 77030, USA
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