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Barros CDS, Coutinho A, Tengan CH. Arginine Supplementation in MELAS Syndrome: What Do We Know about the Mechanisms? Int J Mol Sci 2024; 25:3629. [PMID: 38612442 PMCID: PMC11011289 DOI: 10.3390/ijms25073629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/20/2024] [Accepted: 03/22/2024] [Indexed: 04/14/2024] Open
Abstract
MELAS syndrome, characterized by mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes, represents a devastating mitochondrial disease, with the stroke-like episodes being its primary manifestation. Arginine supplementation has been used and recommended as a treatment for these acute attacks; however, insufficient evidence exists to support this treatment for MELAS. The mechanisms underlying the effect of arginine on MELAS pathophysiology remain unclear, although it is hypothesized that arginine could increase nitric oxide availability and, consequently, enhance blood supply to the brain. A more comprehensive understanding of these mechanisms is necessary to improve treatment strategies, such as dose and regimen adjustments; identify which patients could benefit the most; and establish potential markers for follow-up. This review aims to analyze the existing evidence concerning the mechanisms through which arginine supplementation impacts MELAS pathophysiology and provide the current scenario and perspectives for future investigations.
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Affiliation(s)
| | | | - Celia H. Tengan
- Division of Neurology, Department of Neurology and Neurosurgery, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo 04039-032, Brazil; (C.D.S.B.); (A.C.)
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2
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Grange RMH, Sharma R, Shah H, Reinstadler B, Goldberger O, Cooper MK, Nakagawa A, Miyazaki Y, Hindle AG, Batten AJ, Wojtkiewicz GR, Schleifer G, Bagchi A, Marutani E, Malhotra R, Bloch DB, Ichinose F, Mootha VK, Zapol WM. Hypoxia ameliorates brain hyperoxia and NAD + deficiency in a murine model of Leigh syndrome. Mol Genet Metab 2021; 133:83-93. [PMID: 33752971 PMCID: PMC8489256 DOI: 10.1016/j.ymgme.2021.03.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/07/2021] [Accepted: 03/07/2021] [Indexed: 11/24/2022]
Abstract
Leigh syndrome is a severe mitochondrial neurodegenerative disease with no effective treatment. In the Ndufs4-/- mouse model of Leigh syndrome, continuously breathing 11% O2 (hypoxia) prevents neurodegeneration and leads to a dramatic extension (~5-fold) in lifespan. We investigated the effect of hypoxia on the brain metabolism of Ndufs4-/- mice by studying blood gas tensions and metabolite levels in simultaneously sampled arterial and cerebral internal jugular venous (IJV) blood. Relatively healthy Ndufs4-/- and wildtype (WT) mice breathing air until postnatal age ~38 d were compared to Ndufs4-/- and WT mice breathing air until ~38 days old followed by 4-weeks of breathing 11% O2. Compared to WT control mice, Ndufs4-/- mice breathing air have reduced brain O2 consumption as evidenced by an elevated partial pressure of O2 in IJV blood (PijvO2) despite a normal PO2 in arterial blood, and higher lactate/pyruvate (L/P) ratios in IJV plasma revealed by metabolic profiling. In Ndufs4-/- mice, hypoxia treatment normalized the cerebral venous PijvO2 and L/P ratios, and decreased levels of nicotinate in IJV plasma. Brain concentrations of nicotinamide adenine dinucleotide (NAD+) were lower in Ndufs4-/- mice breathing air than in WT mice, but preserved at WT levels with hypoxia treatment. Although mild hypoxia (17% O2) has been shown to be an ineffective therapy for Ndufs4-/- mice, we find that when combined with nicotinic acid supplementation it provides a modest improvement in neurodegeneration and lifespan. Therapies targeting both brain hyperoxia and NAD+ deficiency may hold promise for treating Leigh syndrome.
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Affiliation(s)
- Robert M H Grange
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Rohit Sharma
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Hardik Shah
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Bryn Reinstadler
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Olga Goldberger
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Marissa K Cooper
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Akito Nakagawa
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Yusuke Miyazaki
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Allyson G Hindle
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Annabelle J Batten
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Gregory R Wojtkiewicz
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Grigorij Schleifer
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Aranya Bagchi
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Eizo Marutani
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Rajeev Malhotra
- Cardiology Division and Cardiovascular Research Center, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Donald B Bloch
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Division of Rheumatology, Allergy and Immunology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Fumito Ichinose
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Vamsi K Mootha
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| | - Warren M Zapol
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
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Abstract
OBJECTIVES Because the central nervous system (CNS) is the second most frequently affected organ in mitochondrial disorders (MIDs) and since paediatric MIDs are increasingly recognised, it is important to know about the morphological CNS abnormalities on imaging in these patients. This review aims at summarising and discussing current knowledge and recent advances concerning CNS imaging abnormalities in paediatric MIDs. METHODS A systematic literature review was conducted. RESULTS The most relevant CNS abnormalities in paediatric MIDs on imaging include white and grey matter lesions, stroke-like lesions as the morphological equivalent of stroke-like episodes, cerebral atrophy, calcifications, optic atrophy, and lactacidosis. Because these CNS lesions may be seen with or without clinical manifestations, it is important to screen all MID patients for cerebral involvement. Some of these lesions may remain unchanged for years whereas others may be dynamic, either in the sense of progression or regression. Typical dynamic lesions are stroke-like lesions and grey matter lesions. Clinically relevant imaging techniques for visualisation of CNS abnormalities in paediatric MIDs are computed tomography, magnetic resonance (MR) imaging, MR spectroscopy, single-photon emission computed tomography, positron-emission tomography, and angiography. CONCLUSIONS CNS imaging in paediatric MIDs is important for diagnosing and monitoring CNS involvement. It also contributes to the understanding of the underlying pathomechanisms that lead to CNS involvement in MIDs.
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Affiliation(s)
| | - Sinda Zarrouk-Mahjoub
- University of Tunis, El Manar and Genomics Platform, Pasteur Institute of Tunis, Tunisia
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4
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Biomarkers for mitochondrial energy metabolism diseases. Essays Biochem 2018; 62:443-454. [PMID: 29980631 DOI: 10.1042/ebc20170111] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 05/22/2018] [Accepted: 05/23/2018] [Indexed: 02/06/2023]
Abstract
Biomarkers are an indicator of biologic or pathogenic processes, whose function is indicating the presence/absence of disease or monitoring disease course and its response to treatment. Since mitochondrial disorders (MDs) can represent a diagnostic challenge for clinicians, due to their clinical and genetic heterogeneity, the identification of easily measurable biomarkers becomes a high priority. Given the complexity of MD, in particular the primary mitochondrial respiratory chain (MRC) diseases due to oxidative phosphorylation (OXPHOS) dysfunction, a reliable single biomarker, relevant for the whole disease group, could be extremely difficult to find, most of times leading the physicians to better consider a 'biosignature' for the diagnosis, rather than a single biochemical marker. Serum biomarkers like lactate and pyruvate are largely determined in the diagnostic algorithm of MD, but they are not specific to this group of disorders. The concomitant determination of creatine (Cr), plasma amino acids, and urine organic acids might be helpful to reinforce the biosignature in some cases. In recent studies, serum fibroblast growth factor 21 (sFGF21) and serum growth differentiation factor 15 (sGDF15) appear to be promising molecules in identifying MD. Moreover, new different approaches have been developed to discover new MD biomarkers. This work discusses the most important biomarkers currently used in the diagnosis of MRC diseases, and some approaches under evaluation, discussing both their utility and weaknesses.
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Finsterer J, Zarrouk-Mahjoub S. Biomarkers for Detecting Mitochondrial Disorders. J Clin Med 2018; 7:E16. [PMID: 29385732 PMCID: PMC5852432 DOI: 10.3390/jcm7020016] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 12/28/2017] [Accepted: 01/19/2018] [Indexed: 01/22/2023] Open
Abstract
(1) Objectives: Mitochondrial disorders (MIDs) are a genetically and phenotypically heterogeneous group of slowly or rapidly progressive disorders with onset from birth to senescence. Because of their variegated clinical presentation, MIDs are difficult to diagnose and are frequently missed in their early and late stages. This is why there is a need to provide biomarkers, which can be easily obtained in the case of suspecting a MID to initiate the further diagnostic work-up. (2) Methods: Literature review. (3) Results: Biomarkers for diagnostic purposes are used to confirm a suspected diagnosis and to facilitate and speed up the diagnostic work-up. For diagnosing MIDs, a number of dry and wet biomarkers have been proposed. Dry biomarkers for MIDs include the history and clinical neurological exam and structural and functional imaging studies of the brain, muscle, or myocardium by ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), MR-spectroscopy (MRS), positron emission tomography (PET), or functional MRI. Wet biomarkers from blood, urine, saliva, or cerebrospinal fluid (CSF) for diagnosing MIDs include lactate, creatine-kinase, pyruvate, organic acids, amino acids, carnitines, oxidative stress markers, and circulating cytokines. The role of microRNAs, cutaneous respirometry, biopsy, exercise tests, and small molecule reporters as possible biomarkers is unsolved. (4) Conclusions: The disadvantages of most putative biomarkers for MIDs are that they hardly meet the criteria for being acceptable as a biomarker (missing longitudinal studies, not validated, not easily feasible, not cheap, not ubiquitously available) and that not all MIDs manifest in the brain, muscle, or myocardium. There is currently a lack of validated biomarkers for diagnosing MIDs.
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Affiliation(s)
- Josef Finsterer
- Krankenanstalt Rudolfstiftung, Postfach 20, 1180 Vienna, Austria.
| | - Sinda Zarrouk-Mahjoub
- El Manar and Genomics Platform, Pasteur Institute of Tunis, University of Tunis, Tunis 1068, Tunisia.
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6
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Steele HE, Horvath R, Lyon JJ, Chinnery PF. Monitoring clinical progression with mitochondrial disease biomarkers. Brain 2017; 140:2530-2540. [PMID: 28969370 PMCID: PMC5841218 DOI: 10.1093/brain/awx168] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 05/14/2017] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial disorders are genetically determined metabolic diseases due to a biochemical deficiency of the respiratory chain. Given that multi-system involvement and disease progression are common features of mitochondrial disorders they carry substantial morbidity and mortality. Despite this, no disease-modifying treatments exist with clear clinical benefits, and the current best management of mitochondrial disease is supportive. Several therapeutic strategies for mitochondrial disorders are now at a mature preclinical stage. Some are making the transition into early-phase patient trials, but the lack of validated biomarkers of disease progression presents a challenge when developing new therapies for patients. This update discusses current biomarkers of mitochondrial disease progression including metabolomics, circulating serum markers, exercise physiology, and both structural and functional imaging. We discuss the advantages and disadvantages of each approach, and consider emerging techniques with a potential role in trials of new therapies.
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Affiliation(s)
- Hannah E Steele
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Rita Horvath
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Jon J Lyon
- GlaxoSmithKline, Molecular Safety and Disposition, Ware, SG12 0DP, UK
| | - Patrick F Chinnery
- Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK.,MRC Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
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Multimodal Imaging-Monitored Progression of Stroke-Like Episodes in a Case of MELAS Syndrome. Clin Nucl Med 2014; 39:e239-40. [DOI: 10.1097/rlu.0b013e318286bd6f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Yu L, Xie S, Xiao J, Wang Z, Zhang X. Quantitative measurement of cerebral oxygen extraction fraction using MRI in patients with MELAS. PLoS One 2013; 8:e79859. [PMID: 24260310 PMCID: PMC3832652 DOI: 10.1371/journal.pone.0079859] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 09/25/2013] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVE To quantify the cerebral OEF at different phases of stroke-like episodes in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) by using MRI. METHODS We recruited 32 patients with MELAS confirmed by gene analysis. Conventional MRI scanning, as well as functional MRI including arterial spin labeling and oxygen extraction fraction imaging, was undertaken to obtain the pathological and metabolic information of the brains at different stages of stroke-like episodes in patients. A total of 16 MRI examinations at the acute and subacute phase and 19 examinations at the interictal phase were performed. In addition, 24 healthy volunteers were recruited for control subjects. Six regions of interest were placed in the anterior, middle, and posterior parts of the bilateral hemispheres to measure the OEF of the brain or the lesions. RESULTS OEF was reduced significantly in brains of patients at both the acute and subacute phase (0.266 ± 0.026) and at the interictal phase (0.295 ± 0.009), compared with normal controls (0.316 ± 0.025). In the brains at the acute and subacute phase of the episode, 13 ROIs were prescribed on the stroke-like lesions, which showed decreased OEF compared with the contralateral spared brain regions. Increased blood flow was revealed in the stroke-like lesions at the acute and subacute phase, which was confined to the lesions. CONCLUSION MRI can quantitatively show changes in OEF at different phases of stroke-like episodes. The utilization of oxygen in the brain seems to be reduced more severely after the onset of episodes in MELAS, especially for those brain tissues involved in the episodes.
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Affiliation(s)
- Lei Yu
- Department of Radiology, Peking University First Hospital, BeiJing, China
| | - Sheng Xie
- Department of Radiology, China-Japan Friendship Hospital, BeiJing, China
- * E-mail: (SX); (JX)
| | - Jiangxi Xiao
- Department of Radiology, Peking University First Hospital, BeiJing, China
- * E-mail: (SX); (JX)
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, BeiJing, China
| | - Xiaodong Zhang
- Department of Radiology, Peking University First Hospital, BeiJing, China
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9
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Wang Z, Xiao J, Xie S, Zhao D, Liu X, Zhang J, Yuan Y, Huang Y. MR evaluation of cerebral oxygen metabolism and blood flow in stroke-like episodes of MELAS. J Neurol Sci 2012; 323:173-7. [PMID: 23062409 DOI: 10.1016/j.jns.2012.09.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Revised: 09/05/2012] [Accepted: 09/10/2012] [Indexed: 10/27/2022]
Abstract
Metabolic information is essential in the investigation of the pathophysiology of stroke-like episodes in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). Here, we used magnetic resonance imaging to evaluate the dynamic metabolic changes before and after a stroke-like episode in two patients with MELAS caused by the mitochondrial DNA mutation A3243G. We performed functional magnetic resonance imaging, including arterial spin labeling and oxygen extraction fraction imaging, and generated cerebral blood flow and oxygen extraction fraction maps. We recruited eight healthy volunteers to define the normal range of the oxygen extraction fraction. We detected a heterogeneous reduction in the oxygen extraction fraction in the brain in the interictal period as well as at the onset of a stroke-like attack. However, the oxygen extraction fraction in the stroke-like lesions normalized in the acute stage. The stroke-like lesions showed consistent hyperperfusion in the acute phase but hypoperfusion in the chronic phase. We have demonstrated the utility of using new magnetic resonance imaging techniques in the evaluation of the pathophysiology of stroke-like lesions. The increased utilization of oxygen in an acute lesion is a novel finding in our study, which might play a role in the oxidative stress.
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Affiliation(s)
- Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, Beijing, 100034, China
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Koga Y, Povalko N, Nishioka J, Katayama K, Yatsuga S, Matsuishi T. Molecular pathology of MELAS and l-arginine effects. Biochim Biophys Acta Gen Subj 2012; 1820:608-14. [DOI: 10.1016/j.bbagen.2011.09.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 07/07/2011] [Accepted: 09/07/2011] [Indexed: 11/30/2022]
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Milh M, Cano A, Halbert C, Chabrol B. Déficit moteur aigu et troubles du métabolisme énergétique. Arch Pediatr 2011. [DOI: 10.1016/s0929-693x(11)71005-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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Ito H, Mori K, Kagami S. Neuroimaging of stroke-like episodes in MELAS. Brain Dev 2011; 33:283-8. [PMID: 20609541 DOI: 10.1016/j.braindev.2010.06.010] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 04/02/2010] [Accepted: 06/11/2010] [Indexed: 11/18/2022]
Abstract
Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) shows sudden neurological deficits that are called 'stroke-like episodes'. With regard to the pathophysiology of stroke-like episodes, so-called mitochondrial angiopathy and cytopathy theories have been proposed, but the subject is still controversial. To clarify this matter and to contribute to the development of a treatment for MELAS, we review here current neuroimaging research and consider the pathophysiology of stroke-like lesions. With regard to diffusion-weighted imaging findings, early reports often showed an elevated apparent diffusion coefficient (ADC) in stroke-like lesions; this was considered to be mainly vasogenic edema in the acute phase and is a different pattern than that in stroke. However, there has recently been an increase in the number of reports of a decrease in ADC; these cases are considered to be cytotoxic edema in the acute phase, which is compatible with stroke. With regard to (1)H-magnetic resonance spectroscopy findings in stroke-like lesions, a decrease in N-acetylaspartate and an increase in lactate have been reported. With regard to single photon emission computed tomography findings for stroke-like lesions in MELAS, an overall trend is hyperperfusion in the acute stage (within 1 month) of stroke-like episodes and hypoperfusion in the chronic stage (several months later). With regard to positron emission tomography, nearly all of these reports are consistent with the mitochondrial cytopathy theory. With regard to neuropathology in MELAS, the most common findings during the chronic stage of stroke-like episodes include foci of necrosis and peculiar vascular changes (abnormalities of mitochondria in small arteries). Concerning the pathology of the acute stage of stroke-like episodes, extensive petechial hemorrhage along the gyri of the cortex corresponding to acute stroke-like lesions has been reported. To clarify the true pathophysiology of stroke-like episodes, we offer three suggestions. First, we must define the precise onset of stroke-like episodes. Second, current studies are limited by the difficulty of imaging just before and just after (within a few minutes) the onset of stroke-like episodes. Third, we hope to establish an experimental animal model. We should conduct a simultaneous multimodal imaging and histological study just before and just after (within a few minutes) the onset of stroke-like episodes in an experimental animal model.
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Affiliation(s)
- Hiromichi Ito
- Department of Pediatrics, School of Medicine, University of Tokushima, Japan.
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Koga Y, Povalko N, Nishioka J, Katayama K, Kakimoto N, Matsuishi T. MELAS and l-arginine therapy: pathophysiology of stroke-like episodes. Ann N Y Acad Sci 2010; 1201:104-10. [DOI: 10.1111/j.1749-6632.2010.05624.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Hall AM, Unwin RJ, Hanna MG, Duchen MR. Renal function and mitochondrial cytopathy (MC): more questions than answers? QJM 2008; 101:755-66. [PMID: 18487272 DOI: 10.1093/qjmed/hcn060] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Our knowledge of mitochondrial biology has advanced significantly in the last 10 years. The effects of mitochondrial dysfunction or cytopathy (MC) on the heart and neuromuscular system are well known, and its involvement in the pathophysiology of several common clinical disorders such as diabetes, hyperlipidaemia and hypertension, is just beginning to emerge; however, its contribution to renal disease has received much less attention, and the available literature raises some interesting questions: Why do children with MC commonly present with a renal phenotype that is often quite different from adults? How does a mutation in mitochondrial DNA (mtDNA) lead to disease at the cellular level, and how can a single mtDNA point mutation result in such a variety of renal- and non-renal phenotypes in isolation or combined? Why are some regions of the nephron seemingly more sensitive to mitochondrial dysfunction and damage by mitochondrial toxins? Perhaps most important of all, what can be done to diagnose and treat MC, now and in the future? In this review we summarize our current understanding of the relationship between mitochondrial biology, renal physiology and clinical nephrology, in an attempt to try to answer some of these questions. Although MC is usually considered a rare defect, it is almost certainly under-diagnosed. A greater awareness and understanding of kidney involvement in MC might lead to new treatment strategies for diseases in which mitochondrial dysfunction is secondary to toxic or ischaemic injury, rather than to an underlying genetic mutation.
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Affiliation(s)
- A M Hall
- Department of Physiology, University College London, London, UK.
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Abstract
INTRODUCTION 99mTc-d,l-hexamethylpropylene amine oxime (99mTc-HMPAO) retention in brain is proportional to cerebral blood flow and related to both the local hemodynamic state and to the cellular content of reduced glutathione. Alterations of the regional distribution of 99mTc-HMPAO retention, with discrepant results, have been reported at functional brain imaging of unipolar depression. Since mitochondrial involvement has been reported in depressed patients, the aim of the study was to explore whether the 99mTc-HMPAO retention at single-photon emission computed tomography in depressed patients may relate to different levels of mitochondrial function. METHODS All patients had audiological and muscular symptoms, somatic symptoms that are common in depression. Citrate synthase (CS) activity assessed in muscle mitochondria correlated strongly with the activities of three mitochondrial respiratory chain enzymes and was used as a marker of mitochondrial function. K-means clustering performed on CS grouped eight patients with low and 11 patients with normal CS. Voxel-based analysis was performed on the two groups by statistical parametric mapping. RESULTS Voxel-based analysis showed significantly higher 99mTc-HMPAO retention in the patients with low CS compared with the patients with normal CS in the posterior and inferior frontal cortex, the superior and posterior temporal cortex, the somato-sensory cortex, and the associative parietal cortex. CONCLUSION Low muscle CS in depressed patients is related to higher regional 99mTc-HMPAO retention that may reflect cerebrovascular adaptation to impaired intracellular metabolism and/or intracellular enzymatic changes, as previously reported in mitochondrial disorder. Mitochondrial dysfunction in varying proportions of the subjects may explain some of the discrepant results for 99mTc-HMPAO retention in depression.
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Shelly MJ, Kelly P, O'Connell MJ. FDG-PET imaging in the investigation of homonymous hemianopia in a patient with MELAS syndrome. Clin Nucl Med 2007; 32:479-80. [PMID: 17515762 DOI: 10.1097/rlu.0b013e3180537852] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Martin J Shelly
- Mater PET/CT Centre, Department of Radiology, Mater Misericordiae University Hospital, Eccles St., Dublin 7, Ireland.
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Iizuka T, Sakai F, Ide T, Miyakawa S, Sato M, Yoshii S. Regional cerebral blood flow and cerebrovascular reactivity during chronic stage of stroke-like episodes in MELAS -- implication of neurovascular cellular mechanism. J Neurol Sci 2007; 257:126-38. [PMID: 17316689 DOI: 10.1016/j.jns.2007.01.040] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Ischemic vascular hypothesis as a causative role in the pathogenesis of stroke-like episodes in MELAS remains to be debated. METHODS This study consisted of two parts. Part 1 is a clinicoradiological study during acute stage of 18 consecutive stroke-like episodes in six patients with MELAS. Part 2 is a SPECT study to assess the regional cerebrovascular reactivity (rCVR) to acetazolamide during chronic stage in five patients with MELAS. RESULTS Headache and epileptic seizure were the most common presenting symptoms. Unique features of acute stroke-like lesions included progressive spread of cortical lesions with vasogenic edema, focal periodic epileptiform discharges, focal hyperperfusion, and cortical laminar necrosis during subacute stage. During chronic stage, SPECT showed hypoperfusion in non-affected occipital cortex in three patients as well as in previously affected regions in four. The rCVR was preserved in three patients, focally impaired in one, and extensively impaired in one, but relatively preserved in the occipital cortex in all patients. CONCLUSIONS Stroke-like episodes could be non-ischemic neurovascular events initiated by neuronal hyperexcitability. Once neuronal hyperexcitability develops in a focal brain region, epileptic activities depolarize adjacent neurons, leading to a propagation of epileptic activities into the surrounding cortex, and resulting in energy imbalance. The mechanisms for neuronal hyperexcitability remain to be elucidated.
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Affiliation(s)
- Takahiro Iizuka
- Department of Neurology, School of Medicine, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa, 228-8555, Japan.
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Nakano K, Tarashima M, Tachikawa E, Noda N, Nakayama T, Sasaki K, Mizoguchi E, Matsuzaki M, Osawa M. Platelet mitochondrial evaluation during cytochrome c and dichloroacetate treatments of MELAS. Mitochondrion 2005; 5:426-33. [PMID: 16290150 DOI: 10.1016/j.mito.2005.10.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Revised: 09/13/2005] [Accepted: 10/12/2005] [Indexed: 10/25/2022]
Abstract
We hypothesized that serial changes in platelet (PLT) mitochondrial enzyme (ME) activities might correspond to the effects of medications for mitochondrial encephalomyopathy and stroke-like episodes (MELAS). Cytochrome c and sodium dichloroacetate (DCA) were given to a 7-year-old girl with MELAS who had an A3243G mitochondrial DNA mutation. The effects were evaluated with whole PLT-ME assays, developed by our group, using a microplate-reader. During cytochrome c treatment, complex II+III (II+III), complex IV (IV) and citrate synthase (CS) activities showed gradual but statistically significant decrease. II+III activity dropped below normal. II+III/CS activity was initially below normal, followed by a transient improvement, then decreased again before the appearance of central nervous system symptoms. II+III, IV, II+III/CS and IV/CS activities reached their lowest levels in association with a stroke-like episode, then increased with DCA treatment. Our results suggest that progressive mitochondrial dysfunction may occur before the stroke-like episodes in MELAS and that DCA treatment may increase mitochondrial activities. Our whole PLT-ME assay system may be useful for serially evaluating mitochondrial functions in relation to clinical symptoms.
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Affiliation(s)
- Kazutoshi Nakano
- Department of Pediatrics, Tokyo Women's Medical University, Shinjuku-ku, Tokyo 162-8666, Japan.
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Kolb SJ, Costello F, Lee AG, White M, Wong S, Schwartz ED, Messé SR, Ellenbogen J, Kasner SE, Galetta SL. Distinguishing ischemic stroke from the stroke-like lesions of MELAS using apparent diffusion coefficient mapping. J Neurol Sci 2003; 216:11-5. [PMID: 14607297 DOI: 10.1016/s0022-510x(03)00218-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We report two patients with migraine, acute visual field defects and other neurological symptoms who were found to have high T(2) signal and FLAIR abnormalities on brain MRI in temporal and parieto-occipital regions. In these patients, the apparent diffusion coefficient (ADC) of their lesions was increased, distinguishing these lesions from those of ischemic stroke. Both were ultimately diagnosed with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). We conclude that conventional MRI when used with diffusion-weighted MR imaging may be invaluable in detecting mitochondrial-related CNS dysfunction.
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Affiliation(s)
- Stephen J Kolb
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
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Tawakol A, Sims K, MacRae C, Friedman JR, Alpert NM, Fischman AJ, Gewirtz H. Myocardial flow regulation in people with mitochondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes/myoclonic epilepsy and ragged red fibers and other mitochondrial syndromes. Coron Artery Dis 2003; 14:197-205. [PMID: 12702922 DOI: 10.1097/01.mca.0000065743.52558.51] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE This study tests the hypothesis that elevated levels of rest myocardial blood flow (MBF), indicative of inefficient aerobic metabolism, will be present in some patients with mitochondrial disorders but structurally normal hearts. BACKGROUND Regulation of MBF is a complex process closely linked to myocardial energy production. Aerobic metabolism in turn depends on normal mitochondrial function and so investigation of patients with mitochondrial disorders may provide important information regarding heritable mechanisms involved in regulation of myocardial flow. METHODS Rest and adenosine-stimulated MBF was measured by the positron emission tomography (PET) 13NH(3) technique in nine patients with mitochondrial disorders and compared with 15 age-matched control participants. RESULTS Basal heart rate (beats/min) and rate pressure product (mm Hg/min) were elevated in patients (76+/-13 and 9302+/-1910, mean+/-SD, respectively) compared with control participants (63+/-9 and 7411+/-1531, P<0.01 and P<0.05, respectively). However, rest and adenosine-stimulated MBF (ml/min per g) did not differ significantly between groups (patients, 1.13+/-0.52 and 4.17+/-0.84, respectively; control participants, 0.85+/-0.30 and 3.56+/-0.63, respectively). Normalization of rest MBF to rate pressure product, however, demonstrated three patients whose values exceeded that of all control participants (chi2=5.71, P<0.05, Fisher's exact test). CONCLUSIONS Elevated basal MBF, in some patients with mitochondrial disorders but structurally normal hearts, suggests the level of basal flow is responsive to efficiency of aerobic metabolism, which closely reflects mitochondrial function. Mitochondrial heteroplasmy with relative sparing of myocardial mitochondria may account for normal basal flow in others with these disorders.
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Affiliation(s)
- Ahmed Tawakol
- Cardiac Unit, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
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