1
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Kumar A, Narkar VA. Nuclear receptors as potential therapeutic targets in peripheral arterial disease and related myopathy. FEBS J 2023; 290:4596-4613. [PMID: 35942640 PMCID: PMC9908775 DOI: 10.1111/febs.16593] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/28/2022] [Accepted: 08/08/2022] [Indexed: 12/31/2022]
Abstract
Peripheral arterial disease (PAD) is a prevalent cardiovascular complication of limb vascular insufficiency, causing ischemic injury, mitochondrial metabolic damage and functional impairment in the skeletal muscle, and ultimately leading to immobility and mortality. While potential therapies have been mostly focussed on revascularization, none of the currently available pharmacological treatments are fully effective in PAD, often leading to amputations, particularly in chronic metabolic diseases. One major limitation of focussed angiogenesis and revascularization as a therapeutic strategy is a limited effect on metabolic restoration and muscle regeneration in the affected limb. Therefore, additional preclinical investigations are needed to discover novel treatment options for PAD preferably targeting multiple aspects of muscle recovery. In this review, we propose nuclear receptors expressed in the skeletal muscle as potential candidates for ischemic muscle repair in PAD. We review classic steroid and orphan receptors that have been reported to be involved in the regulation of paracrine muscle angiogenesis, oxidative metabolism, mitochondrial biogenesis and muscle regeneration, and discuss how these receptors could be critical for recovery from ischemic muscle damage. Furthermore, we identify existing gaps in our understanding of nuclear receptor signalling in the skeletal muscle and propose future areas of research that could be instrumental in exploring nuclear receptors as therapeutic candidates for treating PAD.
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Affiliation(s)
- Ashok Kumar
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204
| | - Vihang A. Narkar
- Brown Foundation Institute of Molecular Medicine, UTHealth McGovern Medical School, Houston, TX, 77030
- University of Texas MD Anderson and UTHealth Graduate School of Biomedical Sciences, Houston, TX, 77030
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2
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Fletcher E, Miserlis D, Sorokolet K, Wilburn D, Bradley C, Papoutsi E, Wilkinson T, Ring A, Ferrer L, Haynatzki G, Smith RS, Bohannon WT, Koutakis P. Diet-induced obesity augments ischemic myopathy and functional decline in a murine model of peripheral artery disease. Transl Res 2023; 260:17-31. [PMID: 37220835 DOI: 10.1016/j.trsl.2023.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/10/2023] [Accepted: 05/15/2023] [Indexed: 05/25/2023]
Abstract
Peripheral artery disease (PAD) causes an ischemic myopathy contributing to patient disability and mortality. Most preclinical models to date use young, healthy rodents with limited translatability to human disease. Although PAD incidence increases with age, and obesity is a common comorbidity, the pathophysiologic association between these risk factors and PAD myopathy is unknown. Using our murine model of PAD, we sought to elucidate the combined effect of age, diet-induced obesity and chronic hindlimb ischemia (HLI) on (1) mobility, (2) muscle contractility, and markers of muscle (3) mitochondrial content and function, (4) oxidative stress and inflammation, (5) proteolysis, and (6) cytoskeletal damage and fibrosis. Following 16-weeks of high-fat, high-sucrose, or low-fat, low-sucrose feeding, HLI was induced in 18-month-old C57BL/6J mice via the surgical ligation of the left femoral artery at 2 locations. Animals were euthanized 4-weeks post-ligation. Results indicate mice with and without obesity shared certain myopathic changes in response to chronic HLI, including impaired muscle contractility, altered mitochondrial electron transport chain complex content and function, and compromised antioxidant defense mechanisms. However, the extent of mitochondrial dysfunction and oxidative stress was significantly greater in obese ischemic muscle compared to non-obese ischemic muscle. Moreover, functional impediments, such as delayed post-surgical recovery of limb function and reduced 6-minute walking distance, as well as accelerated intramuscular protein breakdown, inflammation, cytoskeletal damage, and fibrosis were only evident in mice with obesity. As these features are consistent with human PAD myopathy, our model could be a valuable tool to test new therapeutics.
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Affiliation(s)
- Emma Fletcher
- Department of Biology, Baylor University, Waco, Texas
| | - Dimitrios Miserlis
- Department of Surgery, University of Texas at Austin Dell Medical School, Austin, Texas
| | | | - Dylan Wilburn
- Department of Health, Human Performance and Recreation, Baylor University, Waco, Texas
| | | | | | | | - Andrew Ring
- Department of Biology, Baylor University, Waco, Texas
| | - Lucas Ferrer
- Department of Surgery, University of Texas at Austin Dell Medical School, Austin, Texas
| | - Gleb Haynatzki
- Department of Biostatistics, University of Nebraska Medical Center, Omaha, Nebraska
| | - Robert S Smith
- Department of Surgery, Baylor Scott & White Medical Center, Temple, Texas
| | - William T Bohannon
- Department of Surgery, Baylor Scott & White Medical Center, Temple, Texas
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3
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Signorelli SS, Marino E, Scuto S, Di Raimondo D. Pathophysiology of Peripheral Arterial Disease (PAD): A Review on Oxidative Disorders. Int J Mol Sci 2020; 21:ijms21124393. [PMID: 32575692 PMCID: PMC7352779 DOI: 10.3390/ijms21124393] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/13/2020] [Accepted: 06/18/2020] [Indexed: 12/14/2022] Open
Abstract
Peripheral arterial disease (PAD) is an atherosclerotic disease that affects a wide range of the world’s population, reaching up to 200 million individuals worldwide. PAD particularly affects elderly individuals (>65 years old). PAD is often underdiagnosed or underestimated, although specificity in diagnosis is shown by an ankle/brachial approach, and the high cardiovascular event risk that affected the PAD patients. A number of pathophysiologic pathways operate in chronic arterial ischemia of lower limbs, giving the possibility to improve therapeutic strategies and the outcome of patients. This review aims to provide a well detailed description of such fundamental issues as physical exercise, biochemistry of physical exercise, skeletal muscle in PAD, heme oxygenase 1 (HO-1) in PAD, and antioxidants in PAD. These issues are closely related to the oxidative stress in PAD. We want to draw attention to the pathophysiologic pathways that are considered to be beneficial in order to achieve more effective options to treat PAD patients.
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Affiliation(s)
- Salvatore Santo Signorelli
- Department of Clinical and Experimental Medicine, University of Catania, 95125 Catania, Italy; (E.M.); (S.S.)
- Correspondence: ; Tel.: +39-09-5378-2545
| | - Elisa Marino
- Department of Clinical and Experimental Medicine, University of Catania, 95125 Catania, Italy; (E.M.); (S.S.)
| | - Salvatore Scuto
- Department of Clinical and Experimental Medicine, University of Catania, 95125 Catania, Italy; (E.M.); (S.S.)
| | - Domenico Di Raimondo
- Division of Internal Medicine and Stroke Care, Department of Promoting Health, Maternal-Infant. Excellence and Internal and Specialized Medicine (Promise) G. D’Alessandro, University of Palermo, 90127 Palermo, Italy;
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4
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Ismaeel A, Franco ME, Lavado R, Papoutsi E, Casale GP, Fuglestad M, Mietus CJ, Haynatzki GR, Smith RS, Bohannon WT, Sawicki I, Pipinos II, Koutakis P. Altered Metabolomic Profile in Patients with Peripheral Artery Disease. J Clin Med 2019; 8:E1463. [PMID: 31540015 PMCID: PMC6780416 DOI: 10.3390/jcm8091463] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 09/11/2019] [Accepted: 09/12/2019] [Indexed: 12/15/2022] Open
Abstract
Peripheral artery disease (PAD) is a common atherosclerotic disease characterized by narrowed or blocked arteries in the lower extremities. Circulating serum biomarkers can provide significant insight regarding the disease progression. Here, we explore the metabolomics signatures associated with different stages of PAD and investigate potential mechanisms of the disease. We compared the serum metabolites of a cohort of 26 PAD patients presenting with claudication and 26 PAD patients presenting with critical limb ischemia (CLI) to those of 26 non-PAD controls. A difference between the metabolite profiles of PAD patients from non-PAD controls was observed for several amino acids, acylcarnitines, ceramides, and cholesteryl esters. Furthermore, our data demonstrate that patients with CLI possess an altered metabolomic signature different from that of both claudicants and non-PAD controls. These findings provide new insight into the pathophysiology of PAD and may help develop future diagnostic procedures and therapies for PAD patients.
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Affiliation(s)
- Ahmed Ismaeel
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Marco E Franco
- Department of Environmental Science, Baylor University, Waco, TX 76798, USA
| | - Ramon Lavado
- Department of Environmental Science, Baylor University, Waco, TX 76798, USA
| | - Evlampia Papoutsi
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - George P Casale
- Department of Surgery, University of Nebraska at Medical Center, Omaha, NE 68198, USA
| | - Matthew Fuglestad
- Department of Surgery, University of Nebraska at Medical Center, Omaha, NE 68198, USA
| | - Constance J Mietus
- Department of Surgery, University of Nebraska at Medical Center, Omaha, NE 68198, USA
| | - Gleb R Haynatzki
- Department of Biostatistics, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Robert S Smith
- Department of Surgery, Baylor Scott and White Hospital, Temple, TX 76508, USA
| | - William T Bohannon
- Department of Surgery, Baylor Scott and White Hospital, Temple, TX 76508, USA
| | - Ian Sawicki
- Department of Surgery, Baylor Scott and White Hospital, Temple, TX 76508, USA
| | - Iraklis I Pipinos
- Department of Surgery, University of Nebraska at Medical Center, Omaha, NE 68198, USA
| | - Panagiotis Koutakis
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL 32306, USA.
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5
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Koutakis P, Ismaeel A, Farmer P, Purcell S, Smith RS, Eidson JL, Bohannon WT. Oxidative stress and antioxidant treatment in patients with peripheral artery disease. Physiol Rep 2019; 6:e13650. [PMID: 29611350 PMCID: PMC5880878 DOI: 10.14814/phy2.13650] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 02/12/2018] [Accepted: 02/22/2018] [Indexed: 12/27/2022] Open
Abstract
Peripheral artery disease is an atherosclerotic disease of arterial vessels that mostly affects arteries of lower extremities. Effort induced cycles of ischemia and reperfusion lead to increased reactive oxygen species production by mitochondria. Therefore, the pathophysiology of peripheral artery disease is a consequence of metabolic myopathy, and oxidative stress is the putative major operating mechanism behind the structural and metabolic changes that occur in muscle. In this review, we discuss the evidence for oxidative damage in peripheral artery disease and discuss management strategies related to antioxidant supplementation. We also highlight the major pathways governing oxidative stress in the disease and discuss their implications in disease progression. Potential therapeutic targets and diagnostic methods related to these mechanisms are explored, with an emphasis on the Nrf2 pathway.
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Affiliation(s)
- Panagiotis Koutakis
- Department of Health Human Performance and Recreation, Baylor University, Waco, Texas
| | - Ahmed Ismaeel
- Department of Health Human Performance and Recreation, Baylor University, Waco, Texas
| | - Patrick Farmer
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas
| | - Seth Purcell
- Department of Surgery, Baylor Scott and White Medical Center, Temple, Texas
| | - Robert S Smith
- Department of Surgery, Baylor Scott and White Medical Center, Temple, Texas
| | - Jack L Eidson
- Department of Surgery, Baylor Scott and White Medical Center, Temple, Texas
| | - William T Bohannon
- Department of Surgery, Baylor Scott and White Medical Center, Temple, Texas
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6
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Brass EP, Wang H, Hiatt WR. Multiple skeletal muscle mitochondrial DNA deletions in patients with unilateral peripheral arterial disease. Vasc Med 2016. [DOI: 10.1177/1358836x0000500405] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Peripheral arterial disease (PAD) is associated with metabolic derangements and accumulation of the common 4977 bp mitochondrial DNA (mtDNA) deletion mutation. The current study was undertaken to test the hypothesis that PAD is associated with multiple mtDNA deletions. Gastrocnemius biopsies were obtained from nine patients with unilateral PAD. DNA extracted from the biopsies was analyzed for mtDNA deletions using a primer- shift PCR strategy. Multiple primers and strict, prospective criteria were used to identify deletions. PAD was associated with multiple mtDNA deletions (average of 8.2 distinct deletions in muscle from the hemodynamically affected limb). mtDNA injury was present in both the worse- and less-affected limbs of the unilateral PAD patients, and the estimated degree of mtDNA injury was strongly correlated in the two limbs on an intra-subject basis. The 4977 bp deletion was frequently identified, but was not always the deletion of highest frequency in individual samples. The estimated relative frequency of the 4977 bp deletion was correlated with the overall mtDNA injury in the biopsies. In summary, PAD is associated with mtDNA injury as reflected by multiple deletion mutations. As the mutations are not limited to the ischemic limb in unilateral patients, they are unlikely to contribute to the pathophysiology of claudication.
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Affiliation(s)
- Eric P Brass
- Department of Medicine, Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Hong Wang
- Department of Medicine, Harbor-UCLA Medical Center, Torrance, CA, USA
| | - William R Hiatt
- Section of Vascular Medicine, Division of Geriatrics, University of Colorado Health Sciences Center and the Colorado Prevention Center, Denver, CO, USA
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Ryan TE, Schmidt CA, Green TD, Brown DA, Neufer PD, McClung JM. Mitochondrial Regulation of the Muscle Microenvironment in Critical Limb Ischemia. Front Physiol 2015; 6:336. [PMID: 26635622 PMCID: PMC4649016 DOI: 10.3389/fphys.2015.00336] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 11/02/2015] [Indexed: 01/11/2023] Open
Abstract
Critical limb ischemia (CLI) is the most severe clinical presentation of peripheral arterial disease and manifests as chronic limb pain at rest and/or tissue necrosis. Current clinical interventions are largely ineffective and therapeutic angiogenesis based trials have shown little efficacy, highlighting the dire need for new ideas and novel therapeutic approaches. Despite a decade of research related to skeletal muscle as a determinant of morbidity and mortality outcomes in CLI, very little progress has been made toward an effective therapy aimed directly at the muscle myopathies of this disease. Within the muscle cell, mitochondria are well positioned to modulate the ischemic cellular response, as they are the principal sites of cellular energy production and the major regulators of cellular redox charge and cell death. In this mini review, we update the crucial importance of skeletal muscle to CLI pathology and examine the evolving influence of muscle and endothelial cell mitochondria in the complex ischemic microenvironment. Finally, we discuss the novelty of muscle mitochondria as a therapeutic target for ischemic pathology in the context of the complex co-morbidities often associated with CLI.
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Affiliation(s)
- Terence E Ryan
- Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA ; East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Cameron A Schmidt
- Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA ; East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Tom D Green
- Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA ; East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - David A Brown
- Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA ; East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - P Darrell Neufer
- Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA ; East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Joseph M McClung
- Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA ; East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University Greenville, NC, USA
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Koutakis P, Miserlis D, Myers SA, Kim JKS, Zhu Z, Papoutsi E, Swanson SA, Haynatzki G, Ha DM, Carpenter LA, McComb RD, Johanning JM, Casale GP, Pipinos II. Abnormal accumulation of desmin in gastrocnemius myofibers of patients with peripheral artery disease: associations with altered myofiber morphology and density, mitochondrial dysfunction and impaired limb function. J Histochem Cytochem 2015; 63:256-69. [PMID: 25575565 DOI: 10.1369/0022155415569348] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Patients with peripheral artery disease (PAD) develop a myopathy in their ischemic lower extremities, which is characterized by myofiber degeneration, mitochondrial dysfunction and impaired limb function. Desmin, a protein of the cytoskeleton, is central to maintenance of the structure, shape and function of the myofiber and its organelles, especially the mitochondria, and to translation of sarcomere contraction into muscle contraction. In this study, we investigated the hypothesis that disruption of the desmin network occurs in gastrocnemius myofibers of PAD patients and correlates with altered myofiber morphology, mitochondrial dysfunction, and impaired limb function. Using fluorescence microscopy, we evaluated desmin organization and quantified myofiber content in the gastrocnemius of PAD and control patients. Desmin was highly disorganized in PAD but not control muscles and myofiber content was increased significantly in PAD compared to control muscles. By qPCR, we found that desmin gene transcripts were increased in the gastrocnemius of PAD patients as compared with control patients. Increased desmin and desmin gene transcripts in PAD muscles correlated with altered myofiber morphology, decreased mitochondrial respiration, reduced calf muscle strength and decreased walking performance. In conclusion, our studies identified disruption of the desmin system in gastrocnemius myofibers as an index of the myopathy and limitation of muscle function in patients with PAD.
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Affiliation(s)
- Panagiotis Koutakis
- Department of Surgery (PK, DM, JKK, ZZ, EP, SAS, DMH, LAC, JMJ, GPC, IIP)
| | - Dimitrios Miserlis
- Department of Surgery (PK, DM, JKK, ZZ, EP, SAS, DMH, LAC, JMJ, GPC, IIP)
| | - Sara A Myers
- Nebraska Biomechanics Core Facility, University of Nebraska at Omaha, Nebraska (SAM)
| | - Julian Kyung-Soo Kim
- Department of Surgery (PK, DM, JKK, ZZ, EP, SAS, DMH, LAC, JMJ, GPC, IIP)
| | - Zhen Zhu
- Department of Surgery (PK, DM, JKK, ZZ, EP, SAS, DMH, LAC, JMJ, GPC, IIP)
| | - Evlampia Papoutsi
- Department of Surgery (PK, DM, JKK, ZZ, EP, SAS, DMH, LAC, JMJ, GPC, IIP)
| | - Stanley A Swanson
- Department of Surgery (PK, DM, JKK, ZZ, EP, SAS, DMH, LAC, JMJ, GPC, IIP)
| | - Gleb Haynatzki
- Department of Biostatistics, College of Public Health (GH)
| | - Duy M Ha
- Department of Surgery (PK, DM, JKK, ZZ, EP, SAS, DMH, LAC, JMJ, GPC, IIP)
| | - Lauren A Carpenter
- Department of Surgery (PK, DM, JKK, ZZ, EP, SAS, DMH, LAC, JMJ, GPC, IIP)
| | | | - Jason M Johanning
- Department of Surgery (PK, DM, JKK, ZZ, EP, SAS, DMH, LAC, JMJ, GPC, IIP),Department of Surgery and VA Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, Nebraska (JMJ, IIP)
| | - George P Casale
- Department of Surgery (PK, DM, JKK, ZZ, EP, SAS, DMH, LAC, JMJ, GPC, IIP)
| | - Iraklis I Pipinos
- Department of Surgery (PK, DM, JKK, ZZ, EP, SAS, DMH, LAC, JMJ, GPC, IIP),Department of Surgery and VA Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, Nebraska (JMJ, IIP)
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Pipinos II, Swanson SA, Zhu Z, Nella AA, Weiss DJ, Gutti TL, McComb RD, Baxter BT, Lynch TG, Casale GP. Chronically ischemic mouse skeletal muscle exhibits myopathy in association with mitochondrial dysfunction and oxidative damage. Am J Physiol Regul Integr Comp Physiol 2008; 295:R290-6. [PMID: 18480238 DOI: 10.1152/ajpregu.90374.2008] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A myopathy characterized by mitochondrial pathology and oxidative stress is present in patients with peripheral arterial disease (PAD). Patients with PAD differ in disease severity, mode of presentation, and presence of comorbid conditions. In this study, we used a mouse model of hindlimb ischemia to isolate and directly investigate the effects of chronic inflow arterial occlusion on skeletal muscle microanatomy, mitochondrial function and expression, and oxidative stress. Hindlimb ischemia was induced by staged ligation/division of the common femoral and iliac arteries in C57BL/6 mice, and muscles were harvested 12 wk later. Muscle microanatomy was examined by bright-field microscopy, and mitochondrial content was determined as citrate synthase activity in muscle homogenates and ATP synthase expression by fluorescence microscopy. Electron transport chain (ETC) complexes I through IV were analyzed individually by respirometry. Oxidative stress was assessed as total protein carbonyls and 4-hydroxy-2-nonenal (HNE) adducts and altered expression and activity of manganese superoxide dismutase (MnSOD). Ischemic muscle exhibited histological features of myopathy and increased mitochondrial content compared with control muscle. Complex-dependent respiration was significantly reduced for ETC complexes I, III, and IV in ischemic muscle. Protein carbonyls, HNE adducts, and MnSOD expression were significantly increased in ischemic muscle. MnSOD activity was not significantly changed, suggesting MnSOD inactivation. Using a mouse model, we have demonstrated for the first time that inflow arterial occlusion alone, i.e., in the absence of other comorbid conditions, causes myopathy with mitochondrial dysfunction and increased oxidative stress, recapitulating the muscle pathology of PAD patients.
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Affiliation(s)
- Iraklis I Pipinos
- Department of Surgery, University of Nebraska Medical Center, Omaha, Nebraska 68198-3280, USA.
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10
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Gornik HL, Creager MA. Medical Treatment of Peripheral Arterial Disease. Vasc Med 2006. [DOI: 10.1016/b978-0-7216-0284-4.50024-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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11
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Bauer TA, Brass EP, Hiatt WR. Impaired muscle oxygen use at onset of exercise in peripheral arterial disease. J Vasc Surg 2004; 40:488-93. [PMID: 15337878 DOI: 10.1016/j.jvs.2004.06.025] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES In patients with peripheral arterial disease (PAD), abnormal muscle metabolism and impaired oxygen delivery distal to the arterial occlusions may contribute to the exercise limitation observed in this population. Muscle tissue hemoglobin saturation (StO2), measured with near-infrared spectroscopy, reflects the relative contributions of oxygen delivery and oxygen use. Thus differences in the kinetics of StO2 in response to exercise may yield important insight into the potential mechanisms associated with the PAD exercise impairment. The purposes of this study were to characterize the muscle oxygenation responses in patients with PAD and in healthy control subjects at the onset of exercise, and to compare the kinetics of StO2 desaturation. We hypothesized that at the onset of exercise the kinetics of StO2 desaturation would be slowed in PAD compared with control responses. MATERIAL AND METHODS Six patients with PAD and 6 healthy control subjects from a university center were examined in a prospective cross-sectional analysis that evaluated the desaturation kinetics of StO2 at the onset of walking exercise. On separate visits subjects performed graded treadmill exercise and 3 constant work rate treadmill tests equivalent to approximately 60% (low), approximately 80% (medium), and 100% (peak) of their peak exercise work rate. Gastrocnemious muscle StO2 response profiles (InSpectra tissue spectrometer) were measured at rest and across the rest to exercise transition. Muscle StO2 responses were characterized by an exponential mathematical model. The end point value was taken as the time constant of StO2 desaturation after onset of exercise (ie, equivalent to time to reach approximately 63% of StO2 decrease). RESULTS The patients with PAD and the control subjects were of similar age and activity level. The qualitative patterns of StO2 responses at onset of exercise were also similar between patients and control subjects at all work rates. However, the kinetic time constants of StO2 desaturation were prolonged in patients with PAD versus control subjects (averaged time constant across all work rates, 21.9 +/- 9.4 seconds vs 4.9 +/- 2.2 seconds; P <.01). CONCLUSIONS The slowed muscle StO2 kinetics in PAD are consistent with an impairment in muscle oxygen use at the onset of walking exercise. Impaired muscle metabolism may contribute to the altered physiologic responses to exercise and to exercise impairment in patients with PAD.
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Affiliation(s)
- Timothy A Bauer
- University of Colorado Health Sciences Center, Denver 80262, USA
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12
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Hellsten Y, Skadhauge L, Bangsbo J. Effect of ribose supplementation on resynthesis of adenine nucleotides after intense intermittent training in humans. Am J Physiol Regul Integr Comp Physiol 2004; 286:R182-8. [PMID: 14660478 DOI: 10.1152/ajpregu.00286.2003] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of oral ribose supplementation on the resynthesis of adenine nucleotides and performance after 1 wk of intense intermittent exercise was examined. Eight subjects performed a random double-blind crossover design. The subjects performed cycle training consisting of 15 x 10 s of all-out sprinting twice per day for 7 days. After training the subjects received either ribose (200 mg/kg body wt; Rib) or placebo (Pla) three times per day for 3 days. An exercise test was performed at 72 h after the last training session. Immediately after the last training session, muscle ATP was lowered (P < 0.05) by 25 +/- 2 and 22 +/- 3% in Pla and Rib, respectively. In both Pla and Rib, muscle ATP levels at 5 and 24 h after the exercise were still lower (P < 0.05) than pretraining. After 72 h, muscle ATP was similar (P > 0.05) to pretraining in Rib (24.6 +/- 0.6 vs. 26.2 +/- 0.2 mmol/kg dry wt) but still lower (P < 0.05) in Pla (21.1 +/- 0.5 vs. 26.0 +/- 0.2 mmol/kg dry wt) and higher (P < 0.05) in Rib than in Pla. Plasma hypoxanthine levels after the test performed at 72 h were higher (P < 0.05) in Rib compared with Pla. Mean and peak power outputs during the test performed at 72 h were similar (P > 0.05) in Pla and Rib. The results support the hypothesis that the availability of ribose in the muscle is a limiting factor for the rate of resynthesis of ATP. Furthermore, the reduction in muscle ATP observed after intense training does not appear to be limiting for high-intensity exercise performance.
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Affiliation(s)
- Y Hellsten
- Human Physiology, Copenhagen Muscle Research Centre, Institute for Excersize and Sport Science, DK-2100 Copenhagen, Denmark.
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13
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Pipinos II, Sharov VG, Shepard AD, Anagnostopoulos PV, Katsamouris A, Todor A, Filis KA, Sabbah HN. Abnormal mitochondrial respiration in skeletal muscle in patients with peripheral arterial disease. J Vasc Surg 2003; 38:827-32. [PMID: 14560237 DOI: 10.1016/s0741-5214(03)00602-5] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVE Discrete morphologic, enzymatic and functional changes in skeletal muscle mitochondria have been demonstrated in patients with peripheral arterial disease (PAD). We examined mitochondrial respiration in the gastrocnemius muscle of nine patients (10 legs) with advanced PAD and in nine control patients (nine legs) without evidence of PAD. METHODS Mitochondrial respiratory rates were determined with a Clark electrode in an oxygraph cell containing saponin-skinned muscle bundles. Muscle samples were obtained from the anteromedial aspect of the gastrocnemius muscle, at a level 10 cm distal to the tibial tuberosity. Mitochondria respiratory rate, calculated as nanoatoms of oxygen consumed per minute per milligram of noncollagen protein, were measured at baseline (V(0)), after addition of substrates (malate and glutamate; (V(SUB)), after addition of adenosine diphosphate (ADP) (V(ADP)), and finally, after adenine nucleotide translocase inhibition with atractyloside (V(AT)). The acceptor control ratio, a sensitive indicator of overall mitochondrial function, was calculated as the ratio of the respiratory rate after the addition of ADP to the respiratory rate after adenine nucleotide translocase inhibition with atractyloside (V(ADP)/ V(AT)). RESULTS Respiratory rate in muscle mitochondria from patients with PAD were not significantly different from control values at baseline (0.31 +/- 0.06 vs 0.55 +/- 0.12; P =.09), but V(sub) was significantly lower in patients with PAD compared with control subjects (0.43 +/- 0.07 vs 0.89 +/- 0.20; P <.05), as was V(ADP) (0.69 +/- 0.13 vs 1.24 +/- 0.20; P <.05). Respiratory rates after atractyloside inhibition in patients with PAD were no different from those in control patients (0.47 +/- 0.07 vs 0.45 +/- P =.08). Compared with control values, mitochondria from patients with PAD had a significantly lower acceptor control ratio (1.41 +/- 0.10 vs 2.90 +/- 0.20; P <.001). CONCLUSION Mitochondrial respiratory activity is abnormal in lower extremity skeletal muscle in patients with PAD. When considered in concert with the ultrastructural and enzymatic abnormalities previously documented in mitochondria of chronically ischemic muscle, these data support the concept of defective mitochondrial function as a pathophysiologic component of PAD.
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Affiliation(s)
- Iraklis I Pipinos
- Department of Surgery, University of Nebraska Medical Center, 983280 Nebraska Medical Center, Omaha, NE 68198-3280, USA.
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Hou XY, Green S, Askew CD, Barker G, Green A, Walker PJ. Skeletal muscle mitochondrial ATP production rate and walking performance in peripheral arterial disease. Clin Physiol Funct Imaging 2002; 22:226-32. [PMID: 12076351 DOI: 10.1046/j.1475-097x.2002.00423.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study tested the hypotheses that skeletal muscle mitochondrial ATP production rate (MAPR) is impaired in patients with peripheral arterial disease (PAD) and that it relates positively to their walking performances. Seven untrained patients, eight exercise-trained patients and 11 healthy controls completed a maximal walking test and had muscle sampled from the gastrocnemius medialis muscle. Muscle was analysed for its MAPR in the presence of pyruvate, palmitoyl-L-carnitine or both, as well as citrate synthase (CS) activity. MAPRs were not different between untrained PAD and controls. In contrast, MAPRs (pyruvate) were significantly higher in trained PAD vs. controls. MAPR (pyruvate combinations) was also significantly higher in trained than untrained PAD muscle. MAPR and CS activity were highly correlated with walking performance in patients, but not in controls. These data do not support the hypothesis that isolated mitochondria are functionally impaired in PAD and demonstrate that the muscle mitochondrial capacity to oxidize carbohydrate is positively related to walking performance in these patients.
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Affiliation(s)
- X-Y Hou
- School of Human Movement Studies, Queensland University of Technology, Brisbane, Australia
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Pipinos II, Boska MD, Shepard AD, Anagnostopoulos PV, Katsamouris A. Pentoxifylline reverses oxidative mitochondrial defect in claudicating skeletal muscle. J Surg Res 2002; 102:126-32. [PMID: 11796008 DOI: 10.1006/jsre.2001.6292] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Previous morphologic studies and phosphorus nuclear magnetic resonance spectroscopy (31P MRS) have suggested a primary mitochondrial defect in claudicating skeletal muscle. We hypothesized that pentoxifylline may alleviate this defect. METHODS The response of calf muscle bioenergetics to pentoxifylline was evaluated in 10 male, nondiabetic claudicants with 31P MRS and standard treadmill testing before and after 12 weeks of pentoxifylline therapy. Phosphocreatine (PCr) and adenosinodiphosphate (ADP) recovery rate constants, two very sensitive measures of oxidative mitochondrial function, were measured. RESULTS Seven of the 10 subjects had abnormal baseline PCr (<0.015 s(-1)) and ADP (<0.024 s(-1)) recovery rate constants. These 7 had significant improvement in mitochondrial function with pentoxifylline; their PCr recovery rate constants increased from 0.009 +/- 0.002 to 0.013 +/- 0.002 s(-1) (P = 0.013) and their ADP recovery rate constants increased from 0.015 +/- 0.002 to 0.022 +/- 0.002 s(-1) (P = 0.004). The remaining 3 patients had normal baseline constants and demonstrated no improvement after pentoxifylline therapy. Baseline PCr and ADP recovery rate constants inversely correlated with their corresponding percentage of improvement after pentoxifylline (P < 0.05). In addition the percentage of improvement in the PCr and ADP recovery rate constants correlated with the percentage of improvement in initial claudication distance and maximum walking capacity (P < 0.05). CONCLUSIONS Pentoxifylline improves the mitochondriopathy of claudicating muscle, producing the most improvement in limbs with the worse baseline mitochondrial function. These results point to a potential new mode of action for pentoxifylline in the treatment of claudication and identify a subgroup of patients with the best potential for improvement with treatment.
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Affiliation(s)
- Iraklis I Pipinos
- Department of Surgery, University of Nebraska Medical Center, Omaha, Nebraska 68198-3280, USA
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Green S, Bülow J. Regarding "Phosphorus 31 nuclear magnetic resonance spectroscopy suggests a mitochondrial defect in claudicating skeletal muscle". J Vasc Surg 2001; 33:1133-4. [PMID: 11331866 DOI: 10.1067/mva.2001.114809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Brass EP, Hiatt WR, Gardner AW, Hoppel CL. Decreased NADH dehydrogenase and ubiquinol-cytochrome c oxidoreductase in peripheral arterial disease. Am J Physiol Heart Circ Physiol 2001; 280:H603-9. [PMID: 11158957 DOI: 10.1152/ajpheart.2001.280.2.h603] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Peripheral arterial disease (PAD) is associated with muscle metabolic changes that may contribute to the disability in these patients. However, the biochemical defects in PAD have not been identified. The present study was undertaken to test the hypothesis that PAD is associated with specific defects in skeletal muscle electron transport chain activity. Seventeen patients with PAD and nine age-matched controls underwent gastrocnemius muscle biopsies. There were no differences in the mitochondrial content per gram of skeletal muscle as assessed by citrate synthase activity between the PAD patients and the control subjects. Skeletal muscle NADH dehydrogenase activity was decreased by 27% compared with controls when expressed per unit of citrate synthase activity. Expression of enzyme activities normalized to cytochrome c-oxygen oxidoreductase activity confirmed a 26% decrease in NADH dehydrogenase activity and also demonstrated a 38% decrease in ubiquinol-cytochrome c oxidoreductase activity. Thus PAD is associated with specific changes in muscle mitochondrial electron transport chain activities characterized by relative decreases in NADH dehydrogenase and ubiquinol-cytochrome c oxidoreductase activities, which may contribute to the metabolic abnormalities and decreased exercise performance in these patients.
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Affiliation(s)
- E P Brass
- Department of Medicine, Harbor-University of California Los Angeles Medical Center, Torrance, California 90509, USA.
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Pipinos II, Shepard AD, Anagnostopoulos PV, Katsamouris A, Boska MD. Phosphorus 31 nuclear magnetic resonance spectroscopy suggests a mitochondrial defect in claudicating skeletal muscle. J Vasc Surg 2000; 31:944-52. [PMID: 10805885 DOI: 10.1067/mva.2000.106421] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Decreased oxygen supply is generally accepted as the primary cause of muscle dysfunction in patients with peripheral arterial occlusive disease (PAOD) and intermittent claudication, although reported morphologic changes in the mitochondria of claudicating muscle suggest that impaired energy utilization may also play a role. With the measurement of the phosphate-rich compounds of muscle energy metabolism (adenosinetriphosphate [ATP], adenosinediphosphate [ADP], and phosphocreatine [PCr]) and pH, phosphorus P 31 magnetic resonance spectroscopy ((31)P MRS) provides a unique, noninvasive method to investigate this hypothesis further. METHODS Calf muscle bioenergetics were studied in 12 men with moderate claudication (ankle-brachial index >/=0.5 and </=0.8) and 14 normal control subjects with the use of (31)P MRS and standard treadmill testing. Phosphorus MRS evaluation of the superficial posterior calf muscles was carried out with a 90-second submaximal isometric plantar flexion exercise. This mild exercise was chosen to permit in-magnet testing and to allow study of intrinsic mitochondrial efficiency under conditions of unchallenged blood flow. Phosphocreatine and ADP recovery time constants (t.c.), two very sensitive measures of oxidative mitochondrial function, as well as intracellular pH and ATP production via anaerobic glycolysis were determined during three exercise sessions and the results averaged and compared to known values obtained from a control population. RESULTS During the (31)P MRS protocol, the end exercise intracellular pH (7.11 +/- 0.01 vs 7.11 +/- 0.01) and ATP production by anaerobic glycolysis (0.13 +/- 0.05 vs 0.14 +/- 0.03 mmol/L per second) were no different in PAOD patients versus control subjects, confirming that the protocol exercise did not significantly reduce oxygen supply. Phosphocreatine and ADP recovery t.c. (137 +/- 41 vs 44 +/- 3 seconds and 60 +/- 10 vs 29 +/- 2 seconds, respectively) were significantly slower than normal (P <.05, t test). There was, however, no correlation between these measures of mitochondrial function and any treadmill parameter (P >.5, Pearson moment correlation). CONCLUSIONS Phosphorus 31 MRS provides the first direct evidence of defective energy metabolism in the mitochondria of claudicating calf muscle. This defect appears to be independent of both arterial flow and the severity of occlusive disease in patients with mild to moderate claudication. Coupled with documented ultrastructural and DNA abnormalities in the mitochondria of claudicating skeletal muscle, these data provide evidence for a secondary cause of muscle dysfunction in intermittent claudication.
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Affiliation(s)
- I I Pipinos
- Department of Surgery, Division of Vascular Surgery, Henry Ford Hospital, Detroit, Michigan, USA
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Brass EP, Hiatt WR. Acquired skeletal muscle metabolic myopathy in atherosclerotic peripheral arterial disease. Vasc Med 2000; 5:55-9. [PMID: 10737157 DOI: 10.1177/1358836x0000500109] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Peripheral arterial disease (PAD) is associated with an increased risk of overall cardiovascular mortality, and substantial morbidity resulting from claudication. While the initial disease process is clearly the result of atherosclerosis in the arterial circulation of the limb, altered hemodynamics do not completely explain the pathophysiology of claudication. Work from several laboratories has demonstrated secondary changes in the skeletal muscle of patients with PAD which are consistent with the presence of an acquired metabolic myopathy in these patients. Key findings include an alteration in the expression of mitochondrial enzymes, the accumulation of metabolic intermediates, altered regulation of mitochondrial respiration, increased oxidative stress, and the presence of somatic mutations in the mitochondrial genome. Understanding the metabolic changes associated with PAD is important in understanding the pathophysiology of claudication and in the development of novel therapeutic strategies.
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Affiliation(s)
- E P Brass
- Department of Medicine, Harbor-UCLA Medical Center, Torrance, CA 90509, USA
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Bauer TA, Regensteiner JG, Brass EP, Hiatt WR. Oxygen uptake kinetics during exercise are slowed in patients with peripheral arterial disease. J Appl Physiol (1985) 1999; 87:809-16. [PMID: 10444643 DOI: 10.1152/jappl.1999.87.2.809] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Patients with peripheral arterial disease (PAD) have arterial occlusions that limit peripheral blood flow. This study evaluated the dynamic response in O(2) consumption (VO(2)) at the onset of constant-load exercise (VO(2) kinetics) in patients with PAD. Eight patients with bilateral PAD, seven patients with unilateral PAD, nine age-matched nonsmoking controls, and seven smoking controls performed graded treadmill exercise to assess peak VO(2). Subjects also performed constant-load exercise tests at 2.0 miles/h at 0 and 4% grade to determine VO(2) kinetics. Peak VO(2) was reduced 50% in patients with PAD compared with both control groups (P < 0.05). At 4% grade, phase 2 VO(2) kinetics were significantly slowed for the PAD groups compared with controls (60.1 +/- 15.7 and 58.7 +/- 8.3 s, unilateral and bilateral PAD groups, respectively; compared with 28. 4 +/- 19.3 and 27.9 +/- 8.1 s, nonsmoking and smoking controls, respectively; P < 0.05). No relationship was found between VO(2) kinetics and disease severity. These data demonstrate that VO(2) kinetics are markedly slowed in patients with PAD. The impairment in VO(2) kinetics is not related to smoking status or arterial disease severity and therefore may reflect altered control of skeletal muscle metabolism.
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Affiliation(s)
- T A Bauer
- Section of Vascular Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
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Bhat HK, Hiatt WR, Hoppel CL, Brass EP. Skeletal muscle mitochondrial DNA injury in patients with unilateral peripheral arterial disease. Circulation 1999; 99:807-12. [PMID: 9989967 DOI: 10.1161/01.cir.99.6.807] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Patients with peripheral arterial disease (PAD) have exercise limitation due to claudication-limited pain and metabolic alterations in skeletal muscle. PAD is also associated with oxidative stress, which is a known cause of mitochondrial DNA (mtDNA) injury. The present study was designed to test the hypothesis that PAD is associated with mtDNA injury, as reflected by an increased frequency of a specific 4977-base pair (bp) mtDNA deletion mutation. METHODS AND RESULTS The deletion frequency was quantified in gastrocnemius muscle of 8 patients with unilateral PAD and 10 age-matched control subjects with the use of polymerase chain reaction methodologies. Muscle from the hemodynamically unaffected (less affected) PAD limb showed an 8-fold increased deletion frequency and the hemodynamically affected (worse affected) PAD limb had a 17-fold increased deletion frequency compared with muscle from control subjects. The frequency of the 4977-bp deletion in the worse-affected limb was positively correlated with the age of the patients but not the claudication-limited exercise performance of the patients. Total mtDNA content, citrate synthase activity, and cytochrome c oxidase activity were not different in the muscle from the 3 limb populations. However, the ratio of citrate synthase to cytochrome c oxidase was higher in the worse- versus less-affected limbs of PAD patients. CONCLUSIONS The present study demonstrates a large increase in the frequency of the mtDNA 4977-bp deletion in patients with PAD but in a distribution not limited to the hemodynamically affected limb.
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Affiliation(s)
- H K Bhat
- Department of Medicine, Harbor-UCLA Medical Center, Torrance, Calif. 90509, USA
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Abstract
Whole-body exercise thallium imaging (WBEI) can show abnormalities of leg muscle perfusion in patients with symptomatic peripheral artery disease (PAD). This study compared the exercise distribution of thallium-201 at different levels of the legs in asymptomatic smokers and non-smokers who performed a maximal graded treadmill test. A group of 74 smokers (more than 20 pack-years) with (n = 51) or without coronary artery disease (CAD) (n = 23) were included in group 1 and 64 non-smokers with a low probability of PAD and CAD in group 2. Patients in group 1 were older than the patients in group 2 (58 +/- 9 versus 48 +/- 12 years, p < 0.0001). Indexes of asymmetry were significantly higher in group 1, at each level of the legs, both in anterior and posterior views (0.001 < p < 0.05), except at thigh level in anterior view. Fractional uptake indexes of thallium-201 were significantly lower in group 1 than in group 2 at calf level (p = 0.0001 in anterior and posterior views) and buttocks (p = 0.006 and p = 0.009 in anterior view only). Interextremity asymmetry was four to six times more frequent at calf level in smokers than in non-smokers. These WBEI abnormalities in smokers are highly suggestive of silent PAD or at least decreased vascular reactivity in clinically uninvolved vessels.
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Affiliation(s)
- P Tellier
- Centre de Médecine Nucléaire de l'Artois (CMNA), Clinique Sainte Catherine, Sainte-Catherine-Les-Arras, France
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Brass EP, Hiatt WR. The role of carnitine and carnitine supplementation during exercise in man and in individuals with special needs. J Am Coll Nutr 1998; 17:207-15. [PMID: 9627906 DOI: 10.1080/07315724.1998.10718750] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Carnitine is critical for normal skeletal muscle bioenergetics. Carnitine has a dual role as it is required for long-chain fatty acid oxidation, and also shuttles accumulated acyl groups out of the mitochondria. Muscle requires optimization of both of these metabolic processes during peak exercise performance. Theoretically, carnitine availability may become limiting for either fatty acid oxidation or the removal of acyl-CoAs during exercise. Despite the theoretical basis for carnitine supplementation in otherwise healthy persons to improve exercise performance, clinical data have not demonstrated consistent benefits of carnitine administration. Additionally, most of the anticipated metabolic effects of carnitine supplementation have not been observed in healthy persons. The failure to demonstrate clinical efficacy of carnitine may reflect the complex pharmacokinetics and pharmacodynamics of carnitine supplementation, the challenges of clinical trial design for performance endpoints, or the adequacy of endogenous carnitine content to meet even extreme metabolic demands in the healthy state. In patients with end stage renal disease there is evidence of impaired cellular metabolism, the accumulation of metabolic intermediates and increased carnitine demands to support acylcarnitine production. Years of nutritional changes and dialysis therapy may also lower skeletal muscle carnitine content in these patients. Preliminary data have demonstrated beneficial effects of carnitine supplementation to improve muscle function and exercise capacity in these patients. Peripheral arterial disease (PAD) is also associated with altered muscle metabolic function and endogenous acylcarnitine accumulation. Therapy with either carnitine or propionylcarnitine has been shown to increase claudication-limited exercise capacity in patients with PAD. Further clinical research is needed to define the optimal use of carnitine and acylcarnitines as therapeutic modalities to improve exercise performance in disease states, and any potential benefit in healthy individuals.
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Affiliation(s)
- E P Brass
- Department of Medicine, Harbor-UCLA Medical Center, UCLA School of Medicine, Torrance 90509, USA
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