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Lesnefsky EJ, Chen Q, Hoppel CL. Mitochondrial Metabolism in Aging Heart. Circ Res 2017; 118:1593-611. [PMID: 27174952 DOI: 10.1161/circresaha.116.307505] [Citation(s) in RCA: 216] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/05/2016] [Indexed: 02/07/2023]
Abstract
Altered mitochondrial metabolism is the underlying basis for the increased sensitivity in the aged heart to stress. The aged heart exhibits impaired metabolic flexibility, with a decreased capacity to oxidize fatty acids and enhanced dependence on glucose metabolism. Aging impairs mitochondrial oxidative phosphorylation, with a greater role played by the mitochondria located between the myofibrils, the interfibrillar mitochondria. With aging, there is a decrease in activity of complexes III and IV, which account for the decrease in respiration. Furthermore, aging decreases mitochondrial content among the myofibrils. The end result is that in the interfibrillar area, there is ≈50% decrease in mitochondrial function, affecting all substrates. The defective mitochondria persist in the aged heart, leading to enhanced oxidant production and oxidative injury and the activation of oxidant signaling for cell death. Aging defects in mitochondria represent new therapeutic targets, whether by manipulation of the mitochondrial proteome, modulation of electron transport, activation of biogenesis or mitophagy, or the regulation of mitochondrial fission and fusion. These mechanisms provide new ways to attenuate cardiac disease in elders by preemptive treatment of age-related defects, in contrast to the treatment of disease-induced dysfunction.
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Affiliation(s)
- Edward J Lesnefsky
- From the Division of Cardiology, Department of Medicine, Pauley Heart Center (E.J.L, Q.C.), Departments of Biochemistry and Molecular Biology and Physiology and Biophsyics (E.J.L.), Virginia Commonwealth University, Richmond, VA (E.J.L., Q.C.); Medical Service, McGuire Veterans Affairs Medical Center, Richmond, VA (E.J.L.); and Departments of Pharmacology (C.L.H.) and Medicine (E.J.L., C.L.H.), Center for Mitochondrial Disease (C.L.H.), Case Western Reserve University, School of Medicine, Cleveland, OH
| | - Qun Chen
- From the Division of Cardiology, Department of Medicine, Pauley Heart Center (E.J.L, Q.C.), Departments of Biochemistry and Molecular Biology and Physiology and Biophsyics (E.J.L.), Virginia Commonwealth University, Richmond, VA (E.J.L., Q.C.); Medical Service, McGuire Veterans Affairs Medical Center, Richmond, VA (E.J.L.); and Departments of Pharmacology (C.L.H.) and Medicine (E.J.L., C.L.H.), Center for Mitochondrial Disease (C.L.H.), Case Western Reserve University, School of Medicine, Cleveland, OH
| | - Charles L Hoppel
- From the Division of Cardiology, Department of Medicine, Pauley Heart Center (E.J.L, Q.C.), Departments of Biochemistry and Molecular Biology and Physiology and Biophsyics (E.J.L.), Virginia Commonwealth University, Richmond, VA (E.J.L., Q.C.); Medical Service, McGuire Veterans Affairs Medical Center, Richmond, VA (E.J.L.); and Departments of Pharmacology (C.L.H.) and Medicine (E.J.L., C.L.H.), Center for Mitochondrial Disease (C.L.H.), Case Western Reserve University, School of Medicine, Cleveland, OH.
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Escobales N, Nuñez RE, Jang S, Parodi-Rullan R, Ayala-Peña S, Sacher JR, Skoda EM, Wipf P, Frontera W, Javadov S. Mitochondria-targeted ROS scavenger improves post-ischemic recovery of cardiac function and attenuates mitochondrial abnormalities in aged rats. J Mol Cell Cardiol 2014; 77:136-46. [PMID: 25451170 PMCID: PMC4312194 DOI: 10.1016/j.yjmcc.2014.10.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 10/14/2014] [Accepted: 10/17/2014] [Indexed: 01/21/2023]
Abstract
Mitochondria-generated reactive oxygen species (ROS) play a crucial role in the pathogenesis of aging and age-associated diseases. In this study, we evaluated the effects of XJB-5-131 (XJB), a mitochondria-targeted ROS and electron scavenger, on cardiac resistance to ischemia-reperfusion (IR)-induced oxidative stress in aged rats. Male adult (5-month old, n=17) and aged (29-month old, n=19) Fischer Brown Norway (F344/BN) rats were randomly assigned to the following groups: adult (A), adult+XJB (AX), aged (O), and aged+XJB (OX). XJB was administered 3 times per week (3mg/kg body weight, IP) for four weeks. At the end of the treatment period, cardiac function was continuously monitored in excised hearts using the Langendorff technique for 30 min, followed by 20 min of global ischemia, and 60-min reperfusion. XJB improved post-ischemic recovery of aged hearts, as evidenced by greater left ventricular developed-pressures and rate-pressure products than the untreated, aged-matched group. The state 3 respiration rates at complexes I, II and IV of mitochondria isolated from XJB-treated aged hearts were 57% (P<0.05), 25% (P<0.05) and 28% (P<0.05), respectively, higher than controls. Ca(2+)-induced swelling, an indicator of permeability transition pore opening, was reduced in the mitochondria of XJB-treated aged rats. In addition, XJB significantly attenuated the H2O2-induced depolarization of the mitochondrial inner membrane as well as the total and mitochondrial ROS levels in cultured cardiomyocytes. This study underlines the importance of mitochondrial ROS in aging-induced cardiac dysfunction and suggests that targeting mitochondrial ROS may be an effective therapeutic approach to protect the aged heart against IR injury.
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Affiliation(s)
- Nelson Escobales
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
| | - Rebeca E Nuñez
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
| | - Sehwan Jang
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
| | - Rebecca Parodi-Rullan
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
| | - Sylvette Ayala-Peña
- Department of Pharmacology and Toxicology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
| | - Joshua R Sacher
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Erin M Skoda
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Walter Frontera
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico; Department of Physical Medicine and Rehabilitation, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Sabzali Javadov
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico.
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Boudina S. Cardiac aging and insulin resistance: could insulin/insulin-like growth factor (IGF) signaling be used as a therapeutic target? Curr Pharm Des 2014; 19:5684-94. [PMID: 23448491 DOI: 10.2174/1381612811319320004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 02/18/2013] [Indexed: 01/02/2023]
Abstract
Intrinsic cardiac aging is an independent risk factor for cardiovascular disease and is associated with structural and functional changes that impede cardiac responses to stress and to cardio-protective mechanisms. Although systemic insulin resistance and the associated risk factors exacerbate cardiac aging, cardiac-specific insulin resistance without confounding systemic alterations, could prevent cardiac aging. Thus, strategies aimed to reduce insulin/insulin-like growth factor (IGF) signaling in the heart prevent cardiac aging in lower organisms and in mammals but the mechanisms underlying this protection are not fully understood. In this review, we describe the impact of aging on the cardiovascular system and discuss the mounting evidence that reduced insulin/IGF signaling in the heart could alleviate age-associated alterations and preserve cardiac performance.
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Affiliation(s)
- Sihem Boudina
- Division of Endocrinology, Metabolism and Diabetes, Program in Human Molecular Biology & Genetics, 15 N 2030 E Bldg # 533 Rm. 3410B, Salt Lake City, Utah 84112, USA.
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Effects of caloric restriction on cardiac oxidative stress and mitochondrial bioenergetics: potential role of cardiac sirtuins. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:528935. [PMID: 23577224 PMCID: PMC3614061 DOI: 10.1155/2013/528935] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Accepted: 02/18/2013] [Indexed: 01/25/2023]
Abstract
The biology of aging has not been fully clarified, but the free radical theory of aging is one of the strongest aging theories proposed to date. The free radical theory has been expanded to the oxidative stress theory, in which mitochondria play a central role in the development of the aging process because of their critical roles in bioenergetics, oxidant production, and regulation of cell death. A decline in cardiac mitochondrial function associated with the accumulation of oxidative damage might be responsible, at least in part, for the decline in cardiac performance with age. In contrast, lifelong caloric restriction can attenuate functional decline with age, delay the onset of morbidity, and extend lifespan in various species. The effect of caloric restriction appears to be related to a reduction in cellular damage induced by reactive oxygen species. There is increasing evidence that sirtuins play an essential role in the reduction of mitochondrial oxidative stress during caloric restriction. We speculate that cardiac sirtuins attenuate the accumulation of oxidative damage associated with age by modifying specific mitochondrial proteins posttranscriptionally. Therefore, the distinct role of each sirtuin in the heart subjected to caloric restriction should be clarified to translate sirtuin biology into clinical practice.
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Picard M, Wright KJ, Ritchie D, Thomas MM, Hepple RT. Mitochondrial function in permeabilized cardiomyocytes is largely preserved in the senescent rat myocardium. PLoS One 2012; 7:e43003. [PMID: 22912774 PMCID: PMC3415432 DOI: 10.1371/journal.pone.0043003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 07/16/2012] [Indexed: 01/19/2023] Open
Abstract
The aging heart is characterized by a progressive decline in contractile function and diastolic relaxation. Amongst the factors implicated in these changes is a progressive replacement fibrosis secondary to cardiomyocyte death, oxidative damage, and energetic deficit, each of which may be secondary to impaired mitochondrial function. Here, we performed an in-depth examination of mitochondrial function in saponin-permeabilized cardiomyocyte bundles, a preparation where all mitochondria are represented and their structure intact, from young adult (YA) and senescent (SEN) rats (n = 8 per group). When accounting for increased fibrosis (+19%, P<0.01) and proportional decrease in citrate synthase activity in the SEN myocardium (-23%, P<0.05), mitochondrial respiration and reactive oxygen species (H(2)O(2)) emission across a range of energized states was similar between age groups. Accordingly, the abundance of electron transport chain proteins was also unchanged. Likewise, except for CuZnSOD (-37%, P<0.05), the activity of antioxidant enzymes was unaltered with aging. Although time to mitochondrial permeability transition pore (mPTP) opening was decreased (-25%, P<0.05) in the SEN heart, suggesting sensitization to apoptotic stimuli, this was not associated with a difference in apoptotic index measured by ELISA. Collectively, our results suggest that the function of existing cardiac ventricular mitochondria is relatively preserved in SEN rat heart when measured in permeabilized cells.
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Affiliation(s)
- Martin Picard
- Department of Kinesiology, Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Kathryn J. Wright
- Muscle & Aging Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Darmyn Ritchie
- Muscle & Aging Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Melissa M. Thomas
- Muscle & Aging Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Russell T. Hepple
- Department of Kinesiology, Department of Medicine, McGill University, Montreal, Quebec, Canada
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MacDonald JR, Oellermann M, Rynbeck S, Chang G, Ruggiero K, Cooper GJS, Hickey AJR. Transmural differences in respiratory capacity across the rat left ventricle in health, aging, and streptozotocin-induced diabetes mellitus: evidence that mitochondrial dysfunction begins in the subepicardium. Am J Physiol Cell Physiol 2010; 300:C246-55. [PMID: 21084644 DOI: 10.1152/ajpcell.00294.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
In diabetic cardiomyopathy, ventricular dysfunction occurs in the absence of hypertension or atherosclerosis and is accompanied by altered myocardial substrate utilization and depressed mitochondrial respiration. It is not known if mitochondrial function differs across the left ventricular (LV) wall in diabetes. In the healthy heart, the inner subendocardial region demonstrates higher rates of blood flow, oxygen consumption, and ATP turnover compared with the outer subepicardial region, but published transmural respirometric measurements have not demonstrated differences. We aim to measure mitochondrial function in Wistar rat LV to determine the effects of age, streptozotocin-diabetes, and LV layer. High-resolution respirometry measured indexes of respiration in saponin-skinned fibers dissected from the LV subendocardium and subepicardium of 3-mo-old rats after 1 mo of streptozotocin-induced diabetes and 4-mo-old rats following 2 mo of diabetes. Heart rate and heartbeat duration were measured under isoflurane-anesthesia using a fetal-Doppler, and transmission electron microscopy was employed to observe ultrastructural differences. Heart rate decreased with age and diabetes, whereas heartbeat duration increased with diabetes. While there were no transmural respirational differences in young healthy rat hearts, both myocardial layers showed a respiratory depression with age (30-40%). In 1-mo diabetic rat hearts only subepicardial respiration was depressed, whereas after 2 mo diabetes, respiration in subendocardial and subepicardial layers was depressed and showed elevated leak (state 2) respiration. These data provide evidence that mitochondrial dysfunction is first detectable in the subepicardium of diabetic rat LV, whereas there are measureable changes in LV mitochondria after only 4 mo of aging.
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Affiliation(s)
- J R MacDonald
- University of Auckland, School of Biological Sciences, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand
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Hofer T, Servais S, Seo AY, Marzetti E, Hiona A, Upadhyay SJ, Wohlgemuth SE, Leeuwenburgh C. Bioenergetics and permeability transition pore opening in heart subsarcolemmal and interfibrillar mitochondria: effects of aging and lifelong calorie restriction. Mech Ageing Dev 2009; 130:297-307. [PMID: 19428447 PMCID: PMC2680750 DOI: 10.1016/j.mad.2009.01.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 01/12/2009] [Accepted: 01/21/2009] [Indexed: 10/21/2022]
Abstract
Loss of cardiac mitochondrial function with age may cause increased cardiomyocyte death through mitochondria-mediated release of apoptogenic factors. We investigated ventricular subsarcolemmal (SSM) and interfibrillar (IFM) mitochondrial bioenergetics and susceptibility towards Ca(2+)-induced permeability transition pore (mPTP) opening with aging and lifelong calorie restriction (CR). Cardiac mitochondria were isolated from 8-, 18-, 29- and 37-month-old male Fischer 344 x Brown Norway rats fed either ad libitum (AL) or 40% calorie restricted diets. With age, H(2)O(2) generation did not increase and oxygen consumption did not significantly decrease in either SSM or IFM. Strikingly, IFM displayed an increased susceptibility towards mPTP opening during senescence. In contrast, Ca(2+) retention capacity of SSM was not affected by age, but SSM tolerated much less Ca(2+) than IFM. Only modest age-dependent increases in cytosolic caspase activities and cytochrome c levels were observed and were not affected by CR. Levels of putative mPTP-modulating components: cyclophilin-D, the adenine nucleotide translocase (ANT), and the voltage-dependent ion channel (VDAC) were not affected by aging or CR. In summary, the age-related reduction of Ca(2+) retention capacity in IFM may explain the increased susceptibility to stress-induced cell death in the aged myocardium.
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Affiliation(s)
- Tim Hofer
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
| | - Stephane Servais
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
| | - Arnold Young Seo
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
| | - Emanuele Marzetti
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
- Department of Gerontology, Geriatrics and Physiatrics, Catholic University of the Sacret Heart, Rome 00168, Italy
| | - Asimina Hiona
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
| | - Shashank Jagdish Upadhyay
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
| | - Stephanie Eva Wohlgemuth
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
| | - Christiaan Leeuwenburgh
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, Division of Biology of Aging, University of Florida, Gainesville 32610, USA
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Abstract
Not only the prevalence, but also the mortality due to ischaemic cardiovascular disease is higher in older than in young humans, and the demographic shift towards an ageing population will further increase the prevalence of age-related cardiovascular disease. In order to develop strategies aimed to limit reversible and irreversible myocardial damage in older patients, there is a need to better understand age-induced alterations in protein expression and cell signalling. Cardioprotective phenomena such as ischaemic and pharmacological pre and postconditioning attenuate ischaemia/reperfusion injury in young hearts. Whether or not pre and postconditioning are still effective in aged organs, animals, or patients, i.e. under conditions where such cardioprotection is most relevant, is still a matter of debate; most studies suggest a loss of protection in aged hearts. The present review discusses changes in protein expression and cell signalling important to ischaemia/reperfusion injury with myocardial ageing. The efficacy of cardioprotective manoeuvres, e.g. ischaemic pre and postconditioning in aged organs and animals will be discussed, and the development of strategies aimed to antagonize the age-induced loss of protection will be addressed.
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Affiliation(s)
- Kerstin Boengler
- Institut für Pathophysiologie, Universitätsklinikum Essen, Hufelandstrasse 55, 45122 Essen, Germany
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Estimating relative carbonyl levels in muscle microstructures by fluorescence imaging. Anal Bioanal Chem 2008; 391:2591-8. [PMID: 18548236 DOI: 10.1007/s00216-008-2187-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2007] [Revised: 05/07/2008] [Accepted: 05/13/2008] [Indexed: 10/22/2022]
Abstract
The increase in the levels of protein carbonyls, biomarkers of oxidative stress, appears to play an important role in aging skeletal muscle. However, the exact distributions of carbonyls among various skeletal muscle microstructures still remain largely unknown, partly owing to the lack of adequate techniques to carry out these measurements. This report describes an immunohistochemical approach to determine the relative abundance of carbonyls in the intermyofibrillar mitochondria (IFM), the subsarcolemmal mitochondria (SSM), the cytoplasm, and the extracellular space of skeletal muscle. These morphological features were defined by labeling the nucleus, the Z-lines, and mitochondria. Carbonyls were detected by derivatization with dinitrophenylhydrazine followed by labeling with an Alexa 488-labeled anti-dinitrophenyl primary antibody. Alexa 488 fluorescence (green) in different fiber microstructures was used to estimate the relative abundance of carbonyls. On the basis of the samples examined, preliminary results suggest that the most dramatic age-related changes in carbonyl levels occur in the extracellular space, followed in a decreasing order by SSM, IFM, and the cytoplasm. These observations were confirmed in the soleus and semimembranosus muscles composed predominantly of type I and type II fibers, respectively. This approach could easily be extended to the investigation of carbonyl levels in other muscles (composed of mixed skeletal muscle fiber types) or other tissues in which protein carbonyls are present.
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Judge S, Leeuwenburgh C. Cardiac mitochondrial bioenergetics, oxidative stress, and aging. Am J Physiol Cell Physiol 2007; 292:C1983-92. [PMID: 17344313 DOI: 10.1152/ajpcell.00285.2006] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondria have been a central focus of several theories of aging as a result of their critical role in bioenergetics, oxidant production, and regulation of cell death. A decline in cardiac mitochondrial function coupled with the accumulation of oxidative damage to macromolecules may be causal to the decline in cardiac performance with age. In contrast, regular physical activity and lifelong caloric restriction can prevent oxidative stress, delay the onset of morbidity, increase life span, and reduce the risk of developing several pathological conditions. The health benefits of life long exercise and caloric restriction may be, at least partially, due to a reduction in the chronic amount of mitochondrial oxidant production. In addition, the available data suggest that chronic exercise may serve to enhance antioxidant enzyme activities, and augment certain repair/removal pathways, thereby reducing the amount of oxidative tissue damage. However, the characterization of age-related changes to cardiac mitochondria has been complicated by the fact that two distinct populations of mitochondria exist in the myocardium: subsarcolemmal mitochondria and interfibrillar mitochondria. Several studies now suggest the importance of studying both mitochondrial populations when attempting to elucidate the contribution of mitochondrial dysfunction to myocardial aging. The role that mitochondrial dysfunction and oxidative stress play in contributing to cardiac aging will be discussed along with the use of lifelong exercise and calorie restriction as countermeasures to aging.
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Affiliation(s)
- Sharon Judge
- Dept. of Medicine, University of Florida, College of Medicine, Gainesville, FL 32611, USA
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Lesnefsky EJ, Hoppel CL. Oxidative phosphorylation and aging. Ageing Res Rev 2006; 5:402-33. [PMID: 16831573 DOI: 10.1016/j.arr.2006.04.001] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Revised: 04/01/2006] [Accepted: 04/04/2006] [Indexed: 10/24/2022]
Abstract
This review addresses the data that support the presence and contribution of decreased mitochondrial oxidative phosphorylation during aging to impaired cellular metabolism. Aging impairs substrate oxidation, decreases cellular energy production and increases the production of reactive intermediates that are toxic to the cell. First, the basic principles of mitochondrial oxidative physiology are briefly reviewed. Second, the focus on the relationship of altered mitochondrial respiration to the increased production of reactive oxygen species that are employed by the "rate of living" and the "uncoupling to survive" theories of aging are discussed. Third, the impairment of function of respiration in aging is reviewed using an organ-based approach in mammalian systems. Fourth, the current state of knowledge regarding aging-induced alterations in the composition and function of key mitochondrial constituents is addressed. Model organisms, including C. elegans and D. melanogaster are included where pertinent. Fifth, these defects are related to knowledge regarding the production of reactive oxygen species from specific sites of the electron transport chain.
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Affiliation(s)
- Edward J Lesnefsky
- Department of Medicine, Division of Cardiology, Case Western Reserve University, Cleveland, OH, USA
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Lesnefsky EJ, Hoppel CL. Ischemia–reperfusion injury in the aged heart: role of mitochondria. Arch Biochem Biophys 2003; 420:287-97. [PMID: 14654068 DOI: 10.1016/j.abb.2003.09.046] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The aged heart sustains greater injury during ischemia and reperfusion compared to the adult heart. Aging decreases oxidative phosphorylation and the activity of complexes III and IV only in interfibrillar mitochondria (IFM) that reside among the myofibrils, whereas subsarcolemmal mitochondria (SSM), located beneath the plasma membrane, remain unaltered. The peptide subunit composition of complexes III and IV is intact in aging. The aging defect in complex IV is in the inner membrane lipid environment. The defect in complex III is within the ubiquinol binding site of the cytochrome b subunit. Following ischemia, in the aged heart both SSM and IFM sustain additional decreases in complex III and complex IV activity. In contrast to the aging defect, with ischemia the subunits of complex IV appear to be damaged. Ischemia inactivates the iron-sulfur peptide subunit in complex III. Mitochondria are the major source of the reactive oxygen species that are generated during myocardial ischemia. Complex III is the major site of mitochondrial oxyradical production during ischemia in the adult heart. The role of complex III in the oxidative damage sustained by the aged heart during ischemia, as well as the potential contribution of aging defects in electron transport to ischemic damage in the aged heart, deserves further study. We propose that following ischemic damage to the electron transport chain, the production and release of reactive oxygen species increases from mitochondria in the aged heart, leading to additional damage during reperfusion.
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Affiliation(s)
- Edward J Lesnefsky
- Department of Medicine, Division of Cardiology, Case Western Reserve University, Cleveland, OH 44106, USA
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Mitochondrial electron transport and aging in the heart. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1566-3124(02)11032-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Fannin SW, Lesnefsky EJ, Slabe TJ, Hassan MO, Hoppel CL. Aging selectively decreases oxidative capacity in rat heart interfibrillar mitochondria. Arch Biochem Biophys 1999; 372:399-407. [PMID: 10600182 DOI: 10.1006/abbi.1999.1508] [Citation(s) in RCA: 190] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondrial-derived oxidative injury contributes to cellular aging as well as to reperfusion-induced tissue damage. While the aging-heart suffers greater tissue damage following ischemia and reperfusion than the adult heart, the occurrence of aging-related alterations in mitochondrial oxidative metabolism in the elderly heart has remained uncertain. We determined if aging altered oxidative metabolism in either of the two populations of cardiac mitochondria, subsarcolemmal mitochondria (SSM) that reside beneath the plasma membrane or interfibrillar mitochondria (IFM) located between the myofibrils. SSM and IFM were isolated from 6-month adult and 24- and 28-month elderly Fischer 344 rat hearts. Aging-related alterations were limited to IFM, while SSM remained unaffected. Aging decreased the rate of oxidative phosphorylation in IFM, including when stimulated by electron donors specific for cytochrome oxidase. Cytochrome oxidase enzyme activity was decreased in IFM from aging hearts, while activity in SSM remained similar to adult controls. These findings allow future studies of aging-related decrements in oxidative function to focus upon IFM, while SSM provide an inherent control group of mitochondria that are free of aging-related alterations in oxidative function. The selective alteration of IFM during aging raises the possibility that the consequences of aging-induced mitochondrial dysfunction will be enhanced in specific subcellular regions of the senescent myocyte.
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Affiliation(s)
- S W Fannin
- Department of Veterans Affairs Medical Center, Case Western Reserve University, Cleveland, Ohio, 44106, USA
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Pane G, Wegelin I, Tantini B, Clò C. Enzymes involved in guanine monophosphate metabolism of aging chicken heart. AGING (MILAN, ITALY) 1996; 8:396-9. [PMID: 9061126 DOI: 10.1007/bf03339601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The activities of enzymes involved in GMP metabolism were studied in the heart of aging chickens. In newborn (1-day-old) animals, GMP breakdown apparently leads to the final products of purine metabolism, as the activity of hypoxanthine-guanine phosphoribosyl-transferase (HGPRT), the salvage enzyme of GMP is not detectable. On the contrary, HGPRT shows maximal activity in young (20-day-old) chickens, when xanthine oxidase activity is very low, indicating that the metabolic flux converges on the salvage pathway. Again, maximal activity of the catabolic enzymes and a limited resort to the salvage pathway characterize GMP metabolism of adult (12-month-old) hearts. Finally, in aged (30-month-old) chickens, a reduced GMP catabolism and a greater utilization of the salvage pathway might contribute to the maintenance of the guanine nucleotide pool. In conclusion, the pattern of the activities of enzymes relating to GMP metabolism in the aging heart, compared to AMP metabolism, indicates a parallel temporal regulation of the purine pathways.
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Affiliation(s)
- G Pane
- Institute of Histology and General Embryology, University of Bologna, Italy
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17
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Barogi S, Baracca A, Parenti Castelli G, Bovina C, Formiggini G, Marchetti M, Solaini G, Lenaz G. Lack of major changes in ATPase activity in mitochondria from liver, heart, and skeletal muscle of rats upon ageing. Mech Ageing Dev 1995; 84:139-50. [PMID: 8788241 DOI: 10.1016/0047-6374(95)01640-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
ATP hydrolase activity has been investigated in mitochondria from liver, heart, and skeletal muscle from adult (6 months) and aged (24 months) rats. No significant changes in total ATPase activity were observed in the three tissues, but the oligomycin sensitivity was slightly decreased in heart mitochondria of aged rats. The bicarbonate-induced stimulation of hydrolytic activity was somewhat decreased in mitochondria from aged rats, particularly in liver. No significant change was observed in ATPase activity after release of the endogenous inhibitor protein, IF1. It is concluded that no activity changes to be directly ascribed to the catalytic sector F1 of the enzyme occur upon ageing, but it cannot be excluded that changes in the membrane sector F0 occur as a consequence of mtDNA mutations.
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MESH Headings
- Adenosine Triphosphatases/drug effects
- Adenosine Triphosphatases/metabolism
- Aging/metabolism
- Animals
- Male
- Mitochondria, Heart/drug effects
- Mitochondria, Heart/enzymology
- Mitochondria, Liver/drug effects
- Mitochondria, Liver/enzymology
- Mitochondria, Muscle/drug effects
- Mitochondria, Muscle/enzymology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/ultrastructure
- Oligomycins/pharmacology
- Rats
- Rats, Wistar
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Affiliation(s)
- S Barogi
- Dipartimento di Biochimica G. Moruzzi, University of Bologna, Italy
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18
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Genova ML, Castelluccio C, Fato R, Parenti Castelli G, Merlo Pich M, Formiggini G, Bovina C, Marchetti M, Lenaz G. Major changes in complex I activity in mitochondria from aged rats may not be detected by direct assay of NADH:coenzyme Q reductase. Biochem J 1995; 311 ( Pt 1):105-9. [PMID: 7575440 PMCID: PMC1136125 DOI: 10.1042/bj3110105] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have investigated the respiratory activities and the concentrations of respiratory chain components of mitochondria isolated from the livers and hearts of two groups of rats aged 6 and 24 months respectively. In comparison with the adult controls (6 months), in aged rats there was a decline in total aerobic NADH oxidation in both tissues; only minor (non-significant) changes, however, were found in NADH:coenzyme Q reductase and cytochrome oxidase activities, and there was no change in ubiquinol-cytochrome c reductase activity. The coenzyme Q levels were slightly decreased in mitochondria from both organs of aged rats. The lowered NADH oxidase activity is not due to the slight decrease observed in the coenzyme Q levels, but is the result of decreased Complex I activity. Since the assay of NADH:coenzyme Q reductase requires quinone analogues, none of which can evoke its maximal turnover [Estornell, Fato, Pallotti and Lenaz (1993) FEBS Lett. 332, 127-131], its activity has been calculated indirectly by taking advantage of the relationship that exists between NADH oxidation and ubiquinol oxidation through the coenzyme Q pool. The results, expressed in this way, show a drastic loss of activity of Complex I in both the heart and the liver of aged animals in comparison with adult controls.
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Affiliation(s)
- M L Genova
- Dipartimento di Biochimica G. Moruzzi, University of Bologna, Italy
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19
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Maftah A, Ratinaud MH, Dumas M, Bonté F, Meybeck A, Julien R. Human epidermal cells progressively lose their cardiolipins during ageing without change in mitochondrial transmembrane potential. Mech Ageing Dev 1994; 77:83-96. [PMID: 7745994 DOI: 10.1016/0047-6374(94)90017-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Mitochondria dysfunction is considered to be a major cause of the modifications that occur during cell ageing. For this reason, cardiolipin, a suitable marker of the chondriome, as well as the mitochondrial transmembrane potential were examined in keratinocytes obtained from 9- to 75-year-old women. The study was carried out by flow cytometry using two fluorescent mitochondria probes: nonyl acridine orange, which binds specifically to cardiolipin, and rhodamine 123, which is incorporated mainly in response to transmembrane potential. Cardiolipin levels in cells from elderly donors (75 years old) would be 57% lower (r = 0.540; P = 0.0002) than those in children (9 years old), while the inner transmembrane potential remained unchanged (r = 0.0394; P = 0.8017). The stability of the membrane potential may be explained by either or both of the following hypotheses: (i) the same pool of organelles able to maintain membrane potential is conserved even when cardiolipin levels decrease (ii) mitochondria membrane potential does indeed decrease with age but is compensated by glycolysis energy production. Finally, it may be stated that the fluorescent probes nonyl acridine orange and rhodamine 123 might be of interest in testing the phenotype of senescent cells and would be useful in screening the role of certain specific genes in cell ageing.
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Affiliation(s)
- A Maftah
- Institut de Biotechnologie, UFR des Sciences, Limoges, France
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20
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Castelluccio C, Baracca A, Fato R, Pallotti F, Maranesi M, Barzanti V, Gorini A, Villa RF, Parenti Castelli G, Marchetti M. Mitochondrial activities of rat heart during ageing. Mech Ageing Dev 1994; 76:73-88. [PMID: 7885068 DOI: 10.1016/0047-6374(94)91583-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Some analytical and functional parameters of rat heart mitochondrial have been investigated at six different periods of ageing from 2 to 26 months. The fatty acid composition of the mitochondrial membranes reveals a percentage increase of polyunsaturated fatty acids (20:4 n-6, 22:6 n-3) up to 12 months, followed by a decrease; however, fluorescence polarization of the membrane probe diphenylhexatriene is not changed, revealing that membrane fluidity is not significantly affected. No major change in ubiquinone-9 and in cytochrome content is apparent, indicating that the relative ratio of the respiratory chain components is unmodified. Nevertheless, significant changes in enzyme specific activities are detected: NADH cytochrome c reductase and cytochrome oxidase activities increase up to 12 months, then decrease at 18-26 months; ubiquinol cytochrome c reductase exhibits a peak at 18 months, followed by a decrease. All these activities follow a similar trend during the whole life span of the rat, even though the 'maximum' is different. No significant changes have been found in ATP synthase. Succinate-cytochrome c reductase steadily increases over the whole life span. The results, showing activity decreases in the respiratory enzymes having subunits encoded by mitochondrial DNA, are compatible with the 'mitochondrial' theory of ageing.
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Affiliation(s)
- C Castelluccio
- Dipartimento di Biochimica G. Moruzzi, University of Bologna, Italy
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21
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Kowald A, Kirkwood TB. Mitochondrial mutations, cellular instability and ageing: modelling the population dynamics of mitochondria. Mutat Res 1993; 295:93-103. [PMID: 7689701 DOI: 10.1016/0921-8734(93)90011-q] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
All eukaryotic cells rely on mitochondrial respiration as their major source of metabolic energy (ATP). However, the mitochondria are also the main cellular source of oxygen radicals and the mutation rate of mtDNA is much higher than for chromosomal DNA. Damage to mtDNA is of great importance because it will often impair cellular energy production. However, damaged mitochondria can still replicate because the enzymes for mitochondrial replication are encoded entirely in the cell nucleus. For these reasons, it has been suggested that accumulation of defective mitochondria may be an important contributor to loss of cellular homoeostasis underlying the ageing process. We describe a mathematical model which treats the dynamics of a population of mitochondria subject to radical-induced DNA mutations. The model confirms the existence of an upper threshold level for mutations beyond which the mitochondrial population collapses. This threshold depends strongly on the division rate of the mitochondria. The model also reproduces and explains (i) the decrease in mitochondrial population with age, (ii) the increase in the fraction of damaged mitochondria in old cells, (iii) the increase in radical production per mitochondrion, and (iv) the decrease in ATP production per mitochondrion.
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Affiliation(s)
- A Kowald
- Laboratory of Mathematical Biology, National Institute for Medical Research, London, UK
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22
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Lemeshko VV, Shekh VE. Hypotonic fragility of outer membrane and activation of external pathway of NADH oxidation in rat liver mitochondria are increased with age. Mech Ageing Dev 1993; 68:221-33. [PMID: 8350660 DOI: 10.1016/0047-6374(93)90153-i] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Great importance is attached to structural and functional deterioration of mitochondria as a reason for ageing of an organism; the attention of many scientists has been concentrated on such questions as age changes in the system of oxidative phosphorylation, damage of mitochondrial DNA by free radicals generated in the respiratory chain and inclusion of some fragments of mitochondrial DNA into the nuclear genome. Mitochondrial high amplitude swelling in a cell under some extreme conditions can possibly play a very important role in mechanisms of deterioration of energy transformation function, in activation of lipid peroxidation and mitochondrial DNA damage as a result of outer membrane disruption and release of enzymes from the intermembrane space (e.g. superoxide dismutase amd adenylate kinase). In this work the age changes of the hypotonic fragility of the outer membrane of rat liver mitochondria and the activation of the external, rotenone-insensitive pathway of NADH oxidation have been examined. It is shown that the obligatory condition for activation of rotenone-insensitive NADH oxidation is a break in the outer membrane and that the rate of NADH oxidation substantially increases in the presence of physiological concentrations of Mg2+ which cause a multiple increase in the affinity of the inner membrane to cytochrome c. Research on the rate of rotenone-insensitive NADH oxidation with respect to the osmotic pressure, the ionic strength of the medium, the presence of Mg2+ ions and cytochrome c in the medium has demonstrated a considerable increase in the hypotonic fragility of the outer membrane of liver mitochondria with age in male rats. In female rats the age changes were insignificant. It is supposed that the damage to the outer membrane of mitochondria in cells can serve as one of the possible explanations of both decrease in the reliability of an aged organism under extreme conditions and sex differences of life-span.
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Affiliation(s)
- V V Lemeshko
- Scientific Research Institute of Biology, Kharkov State University, Ukraine
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23
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Guerrieri F, Capozza G, Kalous M, Zanotti F, Drahota Z, Papa S. Age-dependent changes in the mitochondrial F0F1 ATP synthase. Arch Gerontol Geriatr 1992; 14:299-308. [PMID: 15374393 DOI: 10.1016/0167-4943(92)90029-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/1991] [Revised: 02/03/1992] [Accepted: 02/14/1992] [Indexed: 10/27/2022]
Abstract
The age dependence of ATP hydrolase activity and oligomycin sensitive passive proton conduction in sonicated submitochondrial particles of rat brain and rat heart has been investigated. The results show an increase of Vmax of the ATP hydrolase activity and decrease of oligomycin sensitive passive proton conduction with increase of the age of rats from 3 to 6 months. Decrease of ATPase activity and increase of oligomycin sensitive proton conduction occur with further aging to 24 months. Immunoblot analysis shows that both the F(1) and F(0) contents of mitochondria vary with the age of rats, the former exhibiting relatively larger changes.
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Affiliation(s)
- F Guerrieri
- Institute of Medical Biochemistry and Chemistry and Centre for the Study of Mitochondria and Energy Metabolism, C.N.R., University of Bari, Italy
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24
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Abstract
Evidence is discussed for roles of cardiolipins in oxidative phosphorylation mechanisms that regulate State 4 respiration by returning ejected protons across and over bacterial and mitochondrial membrane phospholipids, and that regulate State 3 respiration through the relative contributions of proteins that transport protons, electrons and/or metabolites. The barrier properties of phospholipid bilayers support and regulate the slow proton leak that is the basis for State 4 respiration. Proton permeability is in the range 10(-3)-10(-4) cm s-1 in mitochondria and in protein-free membranes formed from extracted mitochondrial phospholipids or from stable synthetic phosphatidylcholines or phosphatidylethanolamines. The roles of cardiolipins in proton conductance in model phospholipid membrane systems need to be assessed in view of new findings by Hübner et al. [313]: saturated cardiolipins form bilayers whilst natural highly unsaturated cardiolipins form nonlamellar phases. Mitochondrial cardiolipins apparently participate in bilayers formed by phosphatidylcholines and phosphatidylethanolamines. It is not yet clear if cardiolipins themselves conduct protons back across the membrane according to their degree of fatty acyl saturation, and/or modulate proton conductance by phosphatidylcholines and phosphatidylethanolamines. Mitochondrial cardiolipins, especially those with high 18:2 acyl contents, strongly bind many carrier and enzyme proteins that are involved in oxidative phosphorylation, some of which contribute to regulation of State 3 respiration. The role of cardiolipins in biomembrane protein function has been examined by measuring retained phospholipids and phospholipid binding in purified proteins, and by reconstituting delipidated proteins. The reconstitution criterion for the significance of cardiolipin-protein interactions has been catalytical activity; proton-pumping and multiprotein interactions have yet to be correlated. Some proteins, e.g., cytochrome c oxidase are catalytically active when dimyristoylphosphatidylcholine replaces retained cardiolipins. Cardiolipin-protein interactions orient membrane proteins, matrix proteins, and on the outerface receptors, enzymes, and some leader peptides for import; activate enzymes or keep them inactive unless the inner membrane is disrupted; and modulate formation of nonbilayer HII-phases. The capacity of the proton-exchanging uncoupling protein to accelerate thermogenic respiration in brown adipose tissue mitochondria of cold-adapted animals is not apparently affected by the increased cardiolipin unsaturation; this protein seems to take over the protonophoric role of cardiolipins in other mitochondria. Many in vivo influences that affect proton leakage and carrier rates selectively alter cardiolipins in amount per mitochondrial phospholipids, in fatty acyl composition and perhaps in sidedness; other mitochondrial membrane phospholipids respond less or not at all.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- F L Hoch
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor
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25
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Harmon HJ. Lack of age-dependent changes in CO binding to cardiac mitochondrial cytochrome oxidase. Mech Ageing Dev 1990; 55:151-9. [PMID: 2172665 DOI: 10.1016/0047-6374(90)90022-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The rates of CO binding to cytochrome oxidase at low temperatures were studied in mitochondria isolated from the hearts of 3- and 30-32-month-old male F344/N rats. A single apparent energy of activation of 9.6 kcal/mol is observed in mitochondria from 3-month-old rats in the presence of 1% CO. In the presence of 100% CO, the energy of activation is 10.1 kcal/mol and the rate constants of CO recombination following flash photolysis are approximately twice the rate constants in the presence of 1% CO at warm temperatures indicating that an intermediate region near the heme iron can hold a maximum of two CO molecules. In 30-month-old cardiac mitochondria, recombination in the presence of 1% and 100% CO requires crossing barriers of 9.4 kcal/mol and 10.3 kcal/mol height, respectively. The approximate doubling of the values of k at warm temperatures (above 225 K) indicates, as in mitochondria from young animals, that CO migration from solvent to the heme iron involves migration across two similarly sized barriers separating the Fe from an innermost intermediate region I (capable of holding only one CO) and separating region I from intermediate region I2 (capable of holding two CO). The kinetics of CO binding to cytochrome oxidase do not change with increasing age.
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Affiliation(s)
- H J Harmon
- Department of Zoology, Oklahoma State University, Stillwater 74078
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26
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Harmon HJ. Effect of age on kinetics and carbon monoxide binding to cytochrome oxidase in synaptic and non-synaptic brain mitochondria. Mech Ageing Dev 1990; 53:35-48. [PMID: 2157927 DOI: 10.1016/0047-6374(90)90032-b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The kinetic parameters of cytochrome oxidase activity in synaptic and non-synaptic brain mitochondria from 3- and 30-month-old rats were determined at room temperature. The value of Km for cytochrome c increased only 12-13% with age. The maximal velocity did not change with age, but the value of Vmax in synaptic mitochondria is twice that observed in non-synaptic mitochondrial cytochrome oxidase. The kinetics of CO binding to cytochrome oxidase at temperatures from 183 to 225K were also studied in synaptic and non-synaptic mitochondria from 3- and 30-month-old rat forebrains. Age-dependent differences were observed only in mitochondria of synaptic origin. Following flash photolysis at low temperatures, CO migration to the iron requires crossing two free energy barriers separating two intermediate regions from the iron. In 3-month-old synaptic mitochondria, CO must migrate across a 10.3 kcal/mol barrier separating two intermediate regions, I2 and I; a 4.7 kcal/mol barrier separates the innermost region I from the iron. Each intermediate region in 3-month-old cytochrome oxidase can hold only one CO molecule. In 30-month-old synaptic mitochondria, 10.3 kcal/mol barriers separate the two intermediate regions as well as region I and the iron; each intermediate region can hold two CO molecules. Region I2 in non-synaptic cytochrome oxidase at either age can hold two CO molecules and the innermost region I holds only one CO molecule; energy barriers of approximately 10.3 kcal/moIe separate regions I2, I, and the iron. These age-dependent changes may reflect age-dependent conformational changes in cytochrome oxidase.
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Affiliation(s)
- H J Harmon
- Department of Zoology, Oklahoma State University, Stillwater 74078
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27
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Muscari C, Frascaro M, Guarnieri C, Caldarera CM. Mitochondrial function and superoxide generation from submitochondrial particles of aged rat hearts. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1015:200-4. [PMID: 2153403 DOI: 10.1016/0005-2728(90)90021-u] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A decrease in heart function with ageing might be related to an impairment of mitochondrial function, since these organelles produce the greatest fraction of ATP in the myocyte. Mitochondria extracted from Wistar rat hearts at 3, 14, 18 and 24 months of age were employed to evaluate the changes of the respiratory activity during lifetime. A slight decrease of the respiratory rate (QO2) was observed in the 14 month group with respect to the 3 month group when succinate was used as substrate, whereas the respiratory control index (RCI) in the presence of glutamate or succinate increased in the 24 month group. The latter result may be related to a condition of moderate hypertrophy that generally occurs in the ageing heart. Submitochondrial particles (SMP) were also prepared to study the superoxide radicals (O2-) production at the level of rotenone or antimycin-inhibited regions of the respiratory chain. A strong elevation in the O2- generation was observed in the antimycin-inhibited region at 14 months of age; on the contrary, the rate of O2- production remained unchanged in the 24 month group in comparison to the youngest group. These observations correlate well with the enhanced tissue level of oxidized glutathione that was observed at 14 and 18 months of age. The products of lipid peroxidation (TBARS) did not change in the rat heart at any of the ages measured, whereas the levels of fluorescent substances progressively increased beginning from 18 months of age, with a greater extent in the mitochondrial compartment. The present study suggests that age does not substantially affect mitochondrial respiration and energy output in the rat heart, while a greater production by cardiac mitochondria of superoxide anions in the adult rats (14 months) might accelerate the fluorescent pigment formation.
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Affiliation(s)
- C Muscari
- Department of Biochemistry, University of Bologna, Italy
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28
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Schweiger H, Lütjen-Drecoll E, Arnold E, Koch W, Nitsche R, Brand K. Ischemia-induced alterations of mitochondrial structure and function in brain, liver, and heart muscle of young and senescent rats. BIOCHEMICAL MEDICINE AND METABOLIC BIOLOGY 1988; 40:162-85. [PMID: 3190923 DOI: 10.1016/0885-4505(88)90117-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Young and senescent rats (3 and 28-30 months old) were subjected to complete ischemia at 37 degrees C in order to study function and structure of mitochondria isolated from liver, heart muscle, and brain. The rates of energy-coupled respiration and ATP synthesis were found to decrease progressively in relation to time of ischemia. The respiratory rates in the absence of ADP (state 4 respiration) did not increase after exposure to ischemia, suggesting that ischemia primarily affects electron transport rather than the energy coupling system. Mitochondria of heart muscle were more affected by ischemia than mitochondria of brain and liver. Liver and heart muscle mitochondria obtained from young rats were found to be slightly more sensitive to short periods of ischemia than those isolated from senescent animals.
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Affiliation(s)
- H Schweiger
- Department of Surgery, University of Erlangen-Nuremberg, Federal Republic of Germany
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29
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Affiliation(s)
- D G Hazzard
- Office of Resource Development, National Institute on Aging, Bethesda, Maryland 20892
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