ubiquinone and Mitochondrial-Myopathies

Mitochondria are increasingly recognized as key players in genetic and acquired renal diseases. Most mitochondrial cytopathies that cause renal symptoms are characterized by tubular defects, but glomerular, tubulointerstitial and cystic diseases have also been described. For example, defects in coenzyme Q10 (CoQ10) biosynthesis and the mitochondrial DNA 3243 A>G mutation are important causes of focal segmental glomerulosclerosis in children and in adults, respectively. Although they sometimes present with isolated renal findings, mitochondrial diseases are frequently associated with symptoms related to central nervous system and neuromuscular involvement. They can result from mutations in nuclear genes that are inherited according to classic Mendelian rules or from mutations in mitochondrial DNA, which are transmitted according to more complex rules of mitochondrial genetics. Diagnosis of mitochondrial disorders involves clinical characterization of patients in combination with biochemical and genetic analyses. In particular, prompt diagnosis of CoQ10 biosynthesis defects is imperative because of their potentially reversible nature. In acute kidney injury (AKI), mitochondrial dysfunction contributes to the physiopathology of tissue injury, whereas mitochondrial biogenesis has an important role in the recovery of renal function. Potential therapies that target mitochondrial dysfunction or promote mitochondrial regeneration are being developed to limit renal damage during AKI and promote repair of injured tissue.

Topics: Acute Kidney Injury; Alkyl and Aryl Transferases; Animals; DNA, Mitochondrial; Humans; Kearns-Sayre Syndrome; Kidney Diseases; Mitochondria; Mitochondrial Myopathies; Mutation; Oxidative Phosphorylation; Reactive Oxygen Species; Ubiquinone

Mitochondrial disorders are a heterogeneous group of disorders resulting from primary dysfunction of the respiratory chain. Muscle tissue is highly metabolically active, and therefore myopathy is a common element of the clinical presentation of these disorders, although this may be overshadowed by central neurological features. This review is aimed at a general medical and neurologist readership and provides a clinical approach to the recognition, investigation, and treatment of mitochondrial myopathies. Emphasis is placed on practical management considerations while including some recent updates in the field.

Topics: Biopsy; Cytochrome-c Oxidase Deficiency; Deglutition Disorders; Dietary Supplements; Endocrine System Diseases; Exercise Test; Exercise Therapy; Hearing Disorders; Heart Diseases; Humans; Mitochondrial Myopathies; Muscle, Skeletal; Ubiquinone; Vision Disorders; Vitamins

Coenzyme Q (CoQ) is a vital component of the mitochondrial respiratory chain. A number of patients with CoQ deficiency presented with different clinical phenotypes, often affecting skeletal muscle, and responded well to CoQ supplementation. We discuss recent advances in this field with special attention to muscle involvement.. The identification of genetic defects causing CoQ deficiency has allowed to distinguish primary forms, due to mutations in biosynthetic genes, from secondary defects caused either by mutations in genes unrelated to CoQ biosynthesis or by nongenetic factors. To date, none of the patients with genetically proven primary deficiency presented with an exclusively (or prominently) myopathic phenotype. Most patients with myopathy were found to harbor other genetic defects (mutations in electron-transferring-flavoprotein dehydrogenase or mitochondrial DNA). The majority of patients with CoQ deficiency still lack a genetic diagnosis. The pathogenesis of CoQ deficiency cannot be attributed solely to the bioenergetic defect, suggesting that other roles of CoQ, including its antioxidant properties or its role in pyrimidine metabolism, may also play crucial roles.. Early recognition of CoQ deficiency is essential to institute appropriate and timely treatment, thus avoiding irreversible tissue damage.

Topics: Humans; Metabolic Diseases; Mitochondrial Myopathies; Muscle, Skeletal; Muscular Diseases; Ubiquinone

Treatment options for mitochondrial myopathies remain limited despite rapid advances in the understanding of the molecular basis of these conditions. Existing therapies continue to be evaluated and novel treatment strategies are starting to appear on the horizon.. Exercise training continues to show promise as a method of improving exercise tolerance and enhancing oxidative capacity. Coenzyme Q10 deficiency appears to be a relatively common finding in mitochondrial disorders and is likely to benefit from exogenous supplementation. Large-scale randomized clinical trials to evaluate these treatment options are now underway and this represents one of the most important developments in recent years. Activation of the peroxisome proliferator-activated receptor/peroxisome proliferator-activated receptor-gamma coactivator-1alpha pathway has been shown to induce mitochondrial biogenesis leading to a delayed onset of myopathy and prolonged lifespan in mouse models. A ketogenic diet has also been found to induce mitochondrial biogenesis in mice with mitochondrial myopathy.. Therapeutic trials of exercise training and coenzyme Q10 supplementation should continue to be offered to patients with mitochondrial myopathies pending the results of evaluation in randomized clinical trials. Further investigation of peroxisome proliferator-activated receptor/peroxisome proliferator-activated receptor-gamma coactivator-1alpha pathway activation, ketogenic diets and other new strategies is required.

Topics: Animals; Diet, Ketogenic; Dietary Supplements; Exercise Therapy; Humans; Mitochondrial Myopathies; Mutation; PPAR gamma; Ubiquinone; Vitamins

Coenzyme Q(10) (CoQ(10)) is an essential electron carrier in the mitochondrial respiratory chain and an important antioxidant. Deficiency of CoQ(10) is a clinically and molecularly heterogeneous syndrome, which, to date, has been found to be autosomal recessive in inheritance and generally responsive to CoQ(10) supplementation. CoQ(10) deficiency has been associated with five major clinical phenotypes: (1) encephalomyopathy, (2) severe infantile multisystemic disease, (3) cerebellar ataxia, (4) isolated myopathy, and (5) nephrotic syndrome. In a few patients, pathogenic mutations have been identified in genes involved in the biosynthesis of CoQ(10) (primary CoQ(10) deficiencies) or in genes not directly related to CoQ(10) biosynthesis (secondary CoQ(10) deficiencies). Respiratory chain defects, ROS production, and apoptosis contribute to the pathogenesis of primary CoQ(10) deficiencies. In vitro and in vivo studies are necessary to further understand the pathogenesis of the disease and to develop more effective therapies.

Topics: Atrophy; Cerebellum; Child; Chromosome Aberrations; Developmental Disabilities; Disease Progression; DNA Mutational Analysis; Genes, Recessive; Humans; Infant, Newborn; Kidney Diseases; Kidney Glomerulus; Mitochondrial Diseases; Mitochondrial Encephalomyopathies; Mitochondrial Myopathies; Spinocerebellar Degenerations; Ubiquinone

Our understanding of mitochondrial diseases (defined restrictively as defects of the mitochondrial respiratory chain) is expanding rapidly. In this review, I will give the latest information on disorders affecting predominantly or exclusively skeletal muscle.. The most recently described mitochondrial myopathies are due to defects in nuclear DNA, including coenzyme Q10 deficiency and mutations in genes controlling mitochondrial DNA abundance and structure, such as POLG, TK2, and MPV17. Barth syndrome, an X-linked recessive mitochondrial myopathy/cardiopathy, is associated with decreased amount and altered structure of cardiolipin, the main phospholipid of the inner mitochondrial membrane, but a secondary impairment of respiratory chain function is plausible. The role of mutations in protein-coding genes of mitochondrial DNA in causing isolated myopathies has been confirmed. Mutations in tRNA genes of mitochondrial DNA can also cause predominantly myopathic syndromes and--contrary to conventional wisdom--these mutations can be homoplasmic.. Defects in the mitochondrial respiratory chain impair energy production and almost invariably involve skeletal muscle, causing exercise intolerance, cramps, recurrent myoglobinuria, or fixed weakness, which often affects extraocular muscles and results in droopy eyelids (ptosis) and progressive external ophthalmoplegia.

Topics: Cell Nucleus; Coenzymes; DNA, Mitochondrial; Electron Transport Chain Complex Proteins; Humans; Mitochondria, Muscle; Mitochondrial Myopathies; Muscle, Skeletal; Mutation; Ubiquinone

Topics: Adrenergic beta-Antagonists; Angiotensin-Converting Enzyme Inhibitors; Cardiomyopathy, Dilated; Cardiomyopathy, Hypertrophic; Cytochrome b Group; Diagnosis, Differential; DNA, Mitochondrial; Genetic Therapy; Heart Transplantation; Humans; Mitochondrial Myopathies; Mutation; RNA; RNA, Mitochondrial; RNA, Transfer; Ubiquinone

Topics: CD36 Antigens; Coenzyme A Ligases; Coenzymes; Diagnosis, Differential; Fatty Acids; Humans; Hydroxymethylglutaryl-CoA Synthase; Ketone Bodies; Lipid Metabolism, Inborn Errors; Membrane Glycoproteins; Mitochondria; Mitochondrial Myopathies; Organic Anion Transporters; Oxidation-Reduction; Oxo-Acid-Lyases; Prognosis; Ubiquinone

The syndrome of exercise intolerance, cramps, and myoglobinuria is a common presentation of metabolic myopathies and has been associated with several specific inborn errors of glycogen or lipid metabolism. As disorders in fuel utilization presumably impair muscle energy production, it was more than a little surprising that exercise intolerance and myoglobinuria had not been associated with defects in the mitochondrial respiratory chain, the terminal energy-yielding pathway. Recently, however, specific defects in complex I, complex III, and complex IV have been identified in patients with severe exercise intolerance with or without myoglobinuria. All patients were sporadic cases and all harbored mutations in protein-coding genes of muscle mtDNA, suggesting that these were somatic mutations not affecting the germ-line. Another respiratory chain defect, primary coenzyme Q10 (CoQ10) deficiency, also causes exercise intolerance and recurrent myoglobinuria, usually in conjunction with brain symptoms, such as seizures or cerebellar ataxia. Primary CoQ10 deficiency is probably due to mutations in nuclear gene(s) encoding enzymes involved in CoQ10 biosynthesis.

Topics: Adolescent; Adult; Coenzymes; Electron Transport; Electron Transport Complex I; Electron Transport Complex III; Energy Metabolism; Exercise; Exercise Tolerance; Fatty Acids; Female; Glycogen; Humans; Intracellular Membranes; Male; Metabolism, Inborn Errors; Middle Aged; Mitochondria, Muscle; Mitochondrial Myopathies; Muscle Cramp; Muscles; Myoglobinuria; NADH, NADPH Oxidoreductases; Ubiquinone

This review considers primary mitochondrial diseases affecting the respiratory chain. As diseases due to mitochondrial DNA defects defy traditional anatomical classifications, we have not limited our discussion to neuromuscular disorders, but have extended it to include mitochondrial encephalomyopathies. Primary mitochondrial diseases can be due to mutations in either the nuclear or the mitochondrial genome. Nuclear mutations can affect (i) genes encoding enzymatic or structural mitochondrial proteins; (ii) translocases; (iii) mitochondrial protein importation; and (iv) intergenomic signaling. We review briefly recent molecular data and outstanding questions regarding these mendelian disorders, with special emphasis on cytochrome c oxidase deficiency and coenzyme Q10 deficiency. Mitochondrial DNA mutations fall into three main categories: (i) sporadic rearrangements (deletions/duplications); (ii) maternally inherited rearrangements (duplications); and (iii) maternally inherited point mutations. We summarize the most common clinical presentations and discuss pathogenic mechanisms, which remain largely elusive. Uncertainties about pathogenesis extend to the process of cell death, although excitotoxicity in neurons and apoptosis in muscle seem to have important roles.

Topics: Animals; Coenzymes; Cytochrome-c Oxidase Deficiency; DNA, Mitochondrial; Electron Transport Complex IV; Gene Deletion; Humans; Mitochondrial Encephalomyopathies; Mitochondrial Myopathies; Multigene Family; Neuromuscular Diseases; Point Mutation; Ubiquinone

The biochemical and genetic analysis served as the basis for the definition of the following mitochondrial diseases (mt diseases) and the diseases of the mitochondrial deoxyribonucleic acid (mtDNA diseases): mitochondrial myopathy, encephalomyopathy, and cardiomyopathy. The therapy of mitochondrial diseases (in both practice and experiment) belongs to the current trends of research.. The study does not present any new experimental results but in their literary review the authors indicate: a) new trend in biochemical studies of mitochondrial diseases, b) some current knowledge on mtDNA diseases, c) the current trend of mitochondrial disease "redox therapy" by CoQ10, d) significance of the therapeutic task of CoQ10 in four experimental models of the myocardial mitochondria impairment (by ageing, smoking, alcohol, ischemia).. The authors indicate a new perspective for the studies of mitochondrial diseases (mt diseases) and the diseases of the mitochondrial deoxyribonucleic acid (mtDNA diseases) and their therapy not only under experimental conditions, but also in the blood and bioptic samples of patients. (Tab. 3, Fig. 2, Ref. 43.)

Topics: Animals; Cardiomyopathies; Humans; Mitochondria; Mitochondrial Myopathies; Ubiquinone

The authors studied, by in vivo phosphorus magnetic resonance spectroscopy (31P-MRS), the occipital lobes of 19 patients with mitochondrial cytopathies to clarify the functional relation between energy metabolism and concentration of cytosolic free magnesium. All patients displayed defective mitochondrial respiration with low phosphocreatine concentration [PCr] and high inorganic phosphate concentration [Pi] and [ADP]. Cytosolic free [Mg2+] and the readily available free energy (defined as the actual free energy released by the exoergonic reaction of ATP hydrolysis, i.e., deltaG(ATPhyd)) were abnormally low in all patients. Nine patients were treated with coenzyme Q10 (CoQ), which improved the efficiency of the respiratory chain, as shown by an increased [PCr], decreased [Pi] and [ADP], and increased availability of free energy (more negative value of deltaG(ATPhyd)). Treatment with CoQ also increased cytosolic free [Mg2+] in all treated patients. The authors findings demonstrate low brain free [Mg2+] in our patients and indicate that it resulted from failure of the respiratory chain. Free Mg2+ contributes to the absolute value of deltaG(ATPhyd). The results also are consistent with the view that cytosolic [Mg2+] is regulated in the intact brain cell to equilibrate, at least in part, any changes in rapidly available free energy.

Topics: Adolescent; Adult; Aged; Brain; Coenzymes; Cytoprotection; Cytosol; Energy Metabolism; Female; Humans; Magnesium; Magnetic Resonance Spectroscopy; Male; Middle Aged; Mitochondrial Myopathies; Phosphorus; Ubiquinone

With phosphorus magnetic resonance spectroscopy (31P-MRS) we studied in vivo the effect of six-month coenzyme Q10 treatment on the efficiency of brain and skeletal muscle mitochondrial respiration in six patients with different mitochondrial cytopathies. Before CoQ we found a low phosphocreatine content (average of 25% decrease from controls) in the occipital lobes of all patients. Calculated [ADP] and the relative rate of ATP synthesis were high (as an average, 57% and 16% above control group respectively), whereas the cytosolic phosphorylation potential was low (as an average, 60% of control value). 31P-MRS also revealed an average of 29% reduction of the mitochondrial function in the skeletal muscle of patients compared with controls. After a six-month treatment with 150 mg CoQ10/day all brain variables were remarkably improved in all patients, returning within the control range in all cases. Treatment with CoQ also improved the muscle mitochondrial functionality enough to reduce the average deficit to 56% of the control group. These in vivo findings show the beneficial effect of CoQ in patients with mitochondrial cytopathies, and are consistent with the view that increased CoQ concentration in the mitochondrial membrane increases the efficiency of oxidative phosphorylation independently of enzyme deficit.

Topics: Adult; Aged; Brain; Coenzymes; Female; Humans; Magnetic Resonance Spectroscopy; Male; Middle Aged; Mitochondria, Muscle; Mitochondrial Myopathies; Muscle, Skeletal; Phosphocreatine; Phosphorus Isotopes; Ubiquinone

31P magnetic resonance spectroscopy (MRS) was used to study an open therapeutic trial of coenzyme Q10 (CoQ) in mitochondrial encephalomyopathies. Eight patients were treated with 150 mg CoQ per day for 6 months. 31P MRS spectra of calf muscle were recorded at rest, during exercise and in the immediate postexercise recovery period. Although there was an improvement of the mean ratio of phosphocreatine (PCr) to inorganic phosphate during the post-exercise recovery period after 3 months of treatment, this finding was mainly due to a single therapy responder and did not reflect a beneficial effect on the whole group. Improved repletion of PCr persisted after 6 months of therapy. Our study identified a single responder to this therapy, whose response could not be predicted on the basis of clinical, biochemical or molecular data. These findings suggest that therapeutic trials of CoQ should be performed under close metabolic monitoring in order both to identify responders for subsequent long-term treatment and to evaluate possible mechanisms of this supportive therapy.

Topics: Administration, Oral; Adult; Energy Metabolism; Exercise Test; Female; Humans; Longitudinal Studies; Magnetic Resonance Spectroscopy; Male; Middle Aged; Mitochondrial Myopathies; Phosphocreatine; Phosphorus; Radionuclide Imaging; Statistics, Nonparametric; Ubiquinone

This paper briefly summarizes the results of a long-term, open pharmacotherapy trial in 16 patients with well-characterized mitochondrial disease. Outcome measures included repeated clinical evaluation, 31P-NMR spectroscopy and near-infrared spectroscopy. Treated patients appeared to survive longer with less functional disability and medical complications than typically seen in clinical practice.

Topics: Adolescent; Adult; Age of Onset; Antioxidants; Ascorbic Acid; Child; Coenzymes; Female; Humans; Kearns-Sayre Syndrome; Male; MELAS Syndrome; MERRF Syndrome; Methylprednisolone; Middle Aged; Mitochondrial Myopathies; Oxidative Phosphorylation; Oxygen Consumption; Treatment Outcome; Ubiquinone; Vitamin E; Vitamin K; Vitamins

Topics: Acyl-CoA Dehydrogenases; Adolescent; Diet Therapy; Disease Management; Humans; Male; Mitochondrial Myopathies; Mutation, Missense; Rhabdomyolysis; Riboflavin; Secondary Prevention; Ubiquinone; Vitamins

We evaluated coenzyme Q₁₀ (CoQ) levels in patients studied under suspicion of mitochondrial DNA depletion syndromes (MDS) (n=39). CoQ levels were quantified by HPLC, and the percentage of mtDNA depletion by quantitative real-time PCR. A high percentage of MDS patients presented with CoQ deficiency as compared to other mitochondrial patients (Mann-Whitney-U test: p=0.001). Our findings suggest that MDS are frequently associated with CoQ deficiency, as a possible secondary consequence of disease pathophysiology. Assessment of muscle CoQ status seems advisable in MDS patients since the possibility of CoQ supplementation may then be considered as a candidate therapy.

Topics: Adolescent; Ataxia; Child; Child, Preschool; Chromatography, High Pressure Liquid; DNA, Mitochondrial; Female; Humans; Infant; Infant, Newborn; Male; Metabolism, Inborn Errors; Mitochondrial Diseases; Mitochondrial Myopathies; Muscle Weakness; Muscular Diseases; Real-Time Polymerase Chain Reaction; Ubiquinone; Young Adult

Mitochondria are essential organelles with multiple functions, the most well known being the production of adenosine triphosphate (ATP) through oxidative phosphorylation (OXPHOS). The mitochondrial diseases are defined by impairment of OXPHOS. They are a diverse group of diseases that can present in virtually any tissue in either adults or children. Here we review the main molecular mechanisms of mitochondrial diseases, as presently known. A number of disease-causing genetic defects, either in the nuclear genome or in the mitochondria's own genome, mitochondrial DNA (mtDNA), have been identified. The most classical genetic defect causing mitochondrial disease is a mutation in a gene encoding a structural OXPHOS subunit. However, mitochondrial diseases can also arise through impaired mtDNA maintenance, defects in mitochondrial translation factors, and various more indirect mechanisms. The putative consequences of mitochondrial dysfunction on a cellular level are discussed.

Topics: Adenosine Triphosphate; Adult; Child; DNA, Mitochondrial; Humans; Mitochondria; Mitochondrial Diseases; Mitochondrial Myopathies; Oxidative Phosphorylation; Ubiquinone

Coenzyme Q(10) (CoQ(10)) deficiency has been associated with an increasing number of clinical phenotypes. Whereas primary CoQ(10) defects are related to mutations in ubiquinone biosynthetic genes, which are now being unraveled, and respond well to CoQ(10) supplementation, the etiologies, and clinical phenotypes related to secondary deficiencies are largely unknown. The purpose of this multicenter study was to evaluate the frequency of muscle CoQ(10) deficiency in a cohort of 76 patients presenting with clinically heterogeneous mitochondrial phenotypes which included myopathy among their clinical features. A reliable diagnostic tool based on HPLC quantification was employed to measure muscle CoQ(10) levels. A significant proportion of these patients (28 over 76) displayed CoQ(10) deficiency that was clearly secondary in nine patients, who harbored a pathogenic mutation of mitochondrial DNA. This study provides a rationale for future therapeutic trials on the effect of CoQ(10) supplementation in patients with mitochondrial diseases presenting with myopathy among clinical features.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Child, Preschool; Chromatography, High Pressure Liquid; Cohort Studies; DNA, Mitochondrial; Female; Humans; Male; Middle Aged; Mitochondrial Myopathies; Muscle, Skeletal; Mutation; Phenotype; Treatment Outcome; Ubiquinone; Young Adult

Topics: Adult; Anemia, Sideroblastic; Humans; Male; Micronutrients; Mitochondrial Myopathies; Ubiquinone

To report the findings of cystoid macular edema in a patient with chronic progressive external ophthalmoplegia and other systemic features of mitochondrial myopathy.. Observational case report.. Retrospective review of the ophthalmic examination and genetic studies of a patient with chronic progressive ophthalmoplegia.. Fundus photos, retinal optical coherence tomography, and fluorescein angiography were significant for findings consistent with bilateral cystoid macular edema, which were found to have resolved after 18 months without treatment. The medical examination supported the diagnosis of chronic progressive external ophthalmoplegia. Fundus photos, retinal optical coherence tomography, and fluorescein angiography were significant for findings consistent with cystoid macular edema.. This case demonstrates the occurrence CME in a patient with CPEO and additional systemic features.

Topics: Adult; Electrocardiography; Female; Fluorescein Angiography; Glucocorticoids; Humans; Macular Edema; Mitochondrial Myopathies; Ophthalmoplegia, Chronic Progressive External; Retrospective Studies; Tomography, Optical Coherence; Ubiquinone

Topics: Animals; Dietary Supplements; Dog Diseases; Dogs; Male; Mitochondrial Myopathies; Ubiquinone

Coenzyme Q10 (CoQ10 or ubiquinone) is a lipid-soluble component of virtually all cell membranes and has multiple metabolic functions. A major function of CoQ10 is to transport electrons from complexes I and II to complex III in the respiratory chain which resides in the mitochondrial inner membrane. Deficiencies of CoQ10 (MIM 607426) have been associated with four major clinical phenotypes: 1) encephalomyopathy characterized by a triad of recurrent myoglobinuria, brain involvement, and ragged-red fibers; 2) infantile multisystemic disease typically with prominent nephropathy and encephalopathy; 3) cerebellar ataxia with marked cerebellar atrophy; and 4) pure myopathy. Primary CoQ10 deficiencies due to mutations in ubiquinone biosynthetic genes (COQ2, PDSS1, PDSS2, and ADCK3 [CABC1]) have been identified in patients with the infantile multisystemic and cerebellar ataxic phenotypes. In contrast, secondary CoQ10 deficiencies, due to mutations in genes not directly related to ubiquinone biosynthesis (APTX, ETFDH, and BRAF), have been identified in patients with cerebellar ataxia, pure myopathy, and cardiofaciocutaneous syndrome. In many patients with CoQ10 deficiencies, the causative molecular genetic defects remain unknown; therefore, it is likely that mutations in additional genes will be identified as causes of CoQ10 deficiencies.

Topics: Cerebellar Ataxia; Humans; Mitochondrial Encephalomyopathies; Mitochondrial Myopathies; Syndrome; Ubiquinone

Coenzyme Q10 content, pathology evaluation, and electron transport chain (ETC) enzyme analysis were determined in muscle biopsy specimens of 82 children with suspected mitochondrial myopathy. Data were stratified into three groups: "probable" ETC defects, "possible" ETC defects, and disease controls. Muscle total, oxidized, and reduced coenzyme Q10 concentrations were significantly decreased in the probable defect group. Stepwise logistic regression indicated that only total coenzyme Q10 was significantly associated with probable ETC defect. Receiver operator characteristic (ROC) analysis suggested that total muscle coenzyme Q10 was the best predictor of an ETC complex abnormality. Determination of muscle coenzyme Q10 deficiency in children with suspected mitochondrial disease may facilitate diagnosis and encourage earlier supplementation of this agent.

Topics: Adolescent; Child; Child, Preschool; Electron Transport Chain Complex Proteins; Female; Humans; Infant; Male; Mitochondrial Myopathies; Muscle, Skeletal; Ubiquinone

Topics: Alkyl and Aryl Transferases; Coenzymes; Genetic Predisposition to Disease; Humans; Mitochondria; Mitochondrial Encephalomyopathies; Mitochondrial Myopathies; Muscle, Skeletal; Mutation; Stem Cell Transplantation; Transplantation, Homologous; Ubiquinone

Sensory ataxia with neuropathy, dysarthria and ophthalmoparesis represent the clinical triad of SANDO, a specific mitochondrial phenotype first reported in 1997 in association with multiple mitochondrial DNA deletions and mutations in POLG1 or more rarely in the C10orf2 (twinkle-helicase) gene. We report a 44-year-old man with SANDO who harboured two novel mutations (P648R/R807C) in the POLG1 gene.

Topics: Acetylcarnitine; Adult; Coenzymes; DNA Mutational Analysis; DNA Polymerase gamma; DNA-Directed DNA Polymerase; Dysarthria; Hereditary Sensory and Autonomic Neuropathies; Humans; Male; Mitochondrial Myopathies; Muscle, Skeletal; Mutation; Ophthalmoplegia; Peripheral Nerves; Syndrome; Ubiquinone

Primary coenzyme Q(10) (CoQ(10)) deficiency is rare. The encephalomyopathic form, described in few families, is characterized by exercise intolerance, recurrent myoglobinuria, developmental delay, ataxia, and seizures.. To report a rare manifestation of CoQ(10) deficiency with isolated mitochondrial myopathy without central nervous system involvement.. The patient was evaluated for progressive muscle weakness. Comprehensive clinical evaluation and muscle biopsy were performed for histopathologic analysis and mitochondrial DNA and respiratory chain enzyme studies. The patient began taking 150 mg/d of a CoQ(10) supplement.. The elevated creatine kinase and lactate levels with abnormal urine organic acid and acylcarnitine profiles in this patient suggested a mitochondrial disorder. Skeletal muscle histochemical evaluation revealed ragged red fibers, and respiratory chain enzyme analyses showed partial reductions in complex I, I + III, and II + III activities with greater than 200% of normal citrate synthase activity. The CoQ(10) concentration in skeletal muscle was 46% of the normal reference mean. The in vitro addition of 50 micromol/L of coenzyme Q(1) to the succinate cytochrome-c reductase assay of the patient's skeletal muscle whole homogenate increased the succinate cytochrome-c reductase activity 8-fold compared with 2.8-fold in the normal control homogenates. Follow-up of the patient in 6 months demonstrated significant clinical improvement with normalization of creatine kinase and lactate levels.. The absence of central nervous system involvement and recurrent myoglobinuria expands the clinical phenotype of this treatable mitochondrial disorder. The complete recovery of myopathy with exogenous CoQ(10) supplementation observed in this patient highlights the importance of early identification and treatment of this genetic disorder.

Topics: Biopsy; Child; Coenzymes; Creatine Kinase; DNA, Mitochondrial; Electron Transport; Humans; Lactic Acid; Male; Microscopy, Electron, Transmission; Mitochondria, Muscle; Mitochondrial Myopathies; Muscle Weakness; Muscle, Skeletal; Staining and Labeling; Ubiquinone

The authors report 7 years of follow-up evaluation of a patient with coenzyme Q10 (CoQ10) deficiency. Initial symptoms of exercise intolerance and hyperlactatemia improved markedly with substitutive treatment. However, CoQ(10) supplementation did not prevent the onset of a cerebellar syndrome. A switch to idebenone treatment resulted in clinical and metabolic worsening, which disappeared with subsequent CoQ10 treatment. CoQ10 defects may cause progressive neurologic disease despite supplementation.

Topics: Benzoquinones; Carnitine; Cerebellar Ataxia; Cerebellum; Child, Preschool; Disease Progression; Drug Therapy, Combination; Exercise Tolerance; Female; Follow-Up Studies; Humans; Lactates; Magnetic Resonance Imaging; Mitochondria, Muscle; Mitochondrial Myopathies; Muscle, Skeletal; Treatment Failure; Ubiquinone; Vomiting

Idebenone, a synthetic analogue of coenzyme Q10, has been shown to improve cardiac function in patients with Friedreich ataxia and a deficiency of respiratory chain complexes I-III. We describe a woman with severe combined right and left heart failure due to a mitochondrial cardiomyopathy. The patient underwent an endomyocardial biopsy as part of an evaluation for cardiac transplantation. It showed severely decreased respiratory complex activities dependent on CoQ, pointing to CoQ depletion. Following idebenone treatment there was a dramatic improvement in her clinical status with resolution of the heart failure.

Topics: Adult; Antioxidants; Benzoquinones; Biopsy; Cardiomyopathies; Electron Transport Complex I; Electron Transport Complex II; Electron Transport Complex III; Female; Humans; Mitochondrial Myopathies; Multienzyme Complexes; NADH, NADPH Oxidoreductases; Oxidoreductases; Succinate Dehydrogenase; Ubiquinone

The great variability of the human mitochondrial DNA (mtDNA) sequence induces many difficulties in the search for its deleterious mutations. We illustrate these pitfalls by the analysis of the cytochrome b gene of 21 patients affected with a mitochondrial disease. Eighteen different sequence variations were found, five of which were new mutations. Extensive analysis of the cytochrome b gene of 146 controls found 20 supplementary mutations, thus further demonstrating the high variability of the cytochrome b sequence. We fully evaluated the functional relevance of 36 of these 38 mutations using indirect criteria such as the nature of the mutation, its frequency in controls, or the phylogenetic conservation of the mutated amino acid. When appropriate, the mtDNA haplotype, the heteroplasmic state of the mutation, its tissue distribution or its familial transmission were also assessed. The molecular consequences of the mutations, which appeared possibly deleterious in that first step of evaluation, were evaluated on the complex III enzymological properties and protein composition using specific antibodies that we have generated against four of its subunits. Two original deleterious mutations were found in the group of seven patients with overt complex III defect. Both mutations (G15150A (W135X) and T15197C (S151P)) were heteroplasmic and restricted to muscle. They had significant consequences on the complex III structure. In contrast, only two homoplasmic missense mutations with dubious clinical relevance were found in the patients without overt complex III defect.

Topics: Amino Acid Substitution; Antimycin A; Blotting, Western; Cytochrome b Group; DNA Mutational Analysis; DNA, Mitochondrial; Electron Transport Complex III; Gene Frequency; Genetic Variation; Haplotypes; Humans; Methacrylates; Mitochondrial Myopathies; Mutation; Point Mutation; Thiazoles; Ubiquinone

Topics: Humans; Infant; Male; Mitochondrial Myopathies; Reye Syndrome; Ubiquinone

We used in vivo phosphorus magnetic resonance spectroscopy (31P-MRS) to study the effect of CoQ10 on the efficiency of brain and skeletal muscle mitochondrial respiration in ten patients with mitochondrial cytopathies. Before CoQ, brain [PCr] was remarkably lower in patients than in controls, while [Pi] and [ADP] were higher. Brain cytosolic free [Mg2+] and delta G of ATP hydrolysis were also abnormal in all patients. MRS also revealed abnormal mitochondrial function in the skeletal muscles of all patients, as shown by a decreased rate of PCr recovery from exercise. After six-months of treatment with CoQ (150 mg/day), all brain MRS-measurable variables as well as the rate of muscle mitochondrial respiration were remarkably improved in all patients. These in vivo findings show that treatment with CoQ in patients with mitochondrial cytopathies improves mitochondrial respiration in both brain and skeletal muscles, and are consistent with Lenaz's view that increased CoQ concentration in the mitochondrial membrane increases the efficiency of oxidative phosphorylation independently of enzyme deficit.

Topics: Adenosine Diphosphate; Adenosine Triphosphate; Adolescent; Adult; Aged; Brain; Coenzymes; Cytosol; DNA, Mitochondrial; Female; Humans; Magnesium; Magnetic Resonance Spectroscopy; Male; Middle Aged; Mitochondria; Mitochondria, Muscle; Mitochondrial Myopathies; Ophthalmoplegia, Chronic Progressive External; Optic Atrophies, Hereditary; Oxygen Consumption; Phosphates; Phosphorus; Reference Values; Ubiquinone

Topics: Adult; Antioxidants; Coenzymes; Cytoprotection; Diagnosis, Differential; Female; Humans; Mitochondria, Muscle; Mitochondrial Myopathies; Ubiquinone

The aim of the study was to show whether the ACE inhibitor captopril is able to protect the heart against the deleterious effect of passive cigarette smoking on left ventricular mitochondria. Four groups of rabbits were investigated: control (C), passive smoking of three cigarettes twice daily/30 minutes (S), control + captopril (7.5 mg/kg body weight twice daily) (Cap), and smoking + captopril (SCap) as in group 2 and 3. Three weeks lasting passive smoking impaired oxidative phosphorylation, diminished cytochrome oxidase activity and increased the mitochondrial F1-ATPase protein concentration. Moreover, the level of coenzyme Q10 (CoQ10) and coenzyme Q9 were decreased. Simultaneous treatment with captopril prevented partly the decrease of CoQ10 level, deterioration of oxidative phosphorylation, diminution of cytochrome oxidase activity and enhancement of F1-ATPase level. We conclude that captopril protected the myocardium against the harmful effect of passive smoking in rabbits.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Captopril; Cardiomyopathies; Coenzymes; Electron Transport; Electron Transport Complex IV; Energy Metabolism; Heart Ventricles; Mitochondria, Heart; Mitochondrial Myopathies; Oxidative Phosphorylation; Proton-Translocating ATPases; Rabbits; Tobacco Smoke Pollution; Ubiquinone

Exercise tests are widely used as simple, non-invasive screening methods in the differential diagnosis of metabolic myopathies. Exercise protocols have not been standardized with regard to duration of the test, workload, or monitored metabolic parameters. Potentially interfering parameters such as gender or maximal isometric force of the individuals have not been investigated. Here we describe a standardized bicycle ergometry protocol with a stepwise increasing workload between 30 and 100 watts. The venous lactate/pyruvate (L/P) ratio proved to be the one clinically most useful parameter in the functional diagnosis of mitochondrial myopathies with pathological exercise values in all nine examined patients. Additionally, the effects of coenzyme Q therapy in these patients were most clearly mirrored by changes in the L/P ratio. Nonspecifically elevated venous lactate concentrations above 5 mmol/l are rarely found in healthy female volunteers with low maximal isometric force of the M. quadriceps femoris. Other parameters such as serum free fatty acids, ketone bodies, intermediate products of the Krebs cycle or spirometric investigations add only little additional information. The exercise test described may be useful as an additional investigation in the differential diagnosis of metabolic myopathies.

Topics: Adult; Energy Metabolism; Exercise Test; Female; Humans; Isometric Contraction; Lactic Acid; Male; Middle Aged; Mitochondrial Myopathies; Pyruvic Acid; Reference Values; Sensitivity and Specificity; Ubiquinone

A patient with progressive exercise intolerance, proximal weakness, and complex III deficiency in skeletal muscle had a missense mutation in the cytochrome b gene of mitochondrial DNA (G15762A). The mutation, which leads to the substitution of a highly conserved amino acid (G339E), was heteroplasmic (85%) in the patient's muscle and was not present in 100 individuals of different ethnic backgrounds. These data strongly suggest that this molecular defect is the primary cause of the myopathy.

Topics: Adult; Amino Acid Sequence; Animals; Base Sequence; Coenzymes; Conserved Sequence; Cytochrome b Group; DNA, Mitochondrial; Electron Transport Complex III; Evolution, Molecular; Exercise; Female; Folic Acid; Humans; Magnetic Resonance Spectroscopy; Mitochondria, Muscle; Mitochondrial Myopathies; Molecular Sequence Data; Muscle, Skeletal; Mutation, Missense; Phosphates; Phosphocreatine; Sequence Alignment; Sequence Homology, Amino Acid; Ubiquinone

Mitochondrial cardiomyopathies are being studied as metabolic diseases of the cardiac muscle which represents a new approach in metabolic studies. The development of mitochondrial diseases is concomited by an impairment in complexes of mitochondrial respiratory chain, which so far could have been possibly studied exclusively on experimental animals. The method of skinned? fibers enables to measure the pathobiochemical processes in mitochondria in a small amount of bioptic myocardial tissue of patients.. The study is aimed at: applying the method of skinned fibers in biopsy of myocardium in patients, trying to localize the impaired loci of the mitochondrial respiratory chains, prospective early and fast assessment of the diagnosis of mitochondrial cardiomyopathy in patients.. The study brings the first information on the possibility of performing more value measurements of mitochondrial respiratory chains per one bioptic sample from the myocardium in patients. The preliminary results indicate to the prospective possibility of early and fast assessment of the diagnosis of mitochondrial cardio(myo)pathies. The presented results require complementary studies involving the development of "mitochondrial medicine".

Topics: Biopsy; Cardiomyopathies; Flavin-Adenine Dinucleotide; Humans; In Vitro Techniques; Mitochondria, Heart; Mitochondrial Myopathies; Myocardium; NAD; Oxygen Consumption; Ubiquinone

A 2-month-old girl had generalized weakness, profound muscular hypotonia, hepatomegaly and severe lactic acidosis. She needed ventilatory support. Muscle specimen taken at 2 months showed ragged-red fibers, abnormal mitochondria, and reduced cytochrome c oxidase (CCO) staining Biochemical analysis showed CCO activity to be reduced to about 16% of the normal mean. She received carnitine and coenzyme Q10 supplementation from the age of 3 months and abnormal blood lactate values declined to near normal values during the first three weeks. Gradually her condition started to improved: she held her head at 9 months, and walked alone at 15 months. The second biopsy specimen at 3 years and 8 months showed almost normal CCO staining and she was free of clinical signs. This case is an example of a rare benign infantile mitochondrial myopathy caused by CCO deficiency. Early diagnosis is crucial to provide intensive treatment until spontaneous clinical improvement appears. We concluded that carnitine and coenzyme Q10 supplementation was a useful treatment for clinical improvement in patients with a benign infantile mitochondrial myopathy caused by CCO deficiency.

Topics: Carnitine; Cytochrome-c Oxidase Deficiency; Female; Humans; Infant; Mitochondrial Myopathies; Ubiquinone

Overt mitochondrial diseases associated with mitochondrial DNA mutations are characterized by a decline in mitochondrial respiratory function. Similarly, a progressive decline in mitochondrial respiratory function associated with mitochondrial DNA mutations is clearly evidenced in aged human subjects. This communication is concerned with the development of a rat model for the study of bioenergy decline associated with the ageing process and overt mitochondrial diseases. The model involves the treatment of young rats with AZT to induce skeletal and cardiac myopathies. It has shown that there is a decline in soleus muscle function in vivo and that this decline is mirrored in the capacity of heart sub-mitochondrial particles to maintain bioenergy function. Coenzyme Q10 and several analogs were administered with AZT as potential therapeutics for the re-energization of affected tissues. Coenzyme Q10 and especially decyl Q were found to be therapeutically beneficial by both in vivo improvement in soleus muscle function and in vitro cardiac mitochondrial membrane potential capacity. Sub-mitochondrial particles were also prepared from heart mitochondria of young and aged rats. The particles prepared from the aged rats were found to have a decreased ability to maintain membrane potential as compared to those derived from the young rats.

Topics: Animals; Cardiomyopathies; Coenzymes; Humans; Mitochondria, Heart; Mitochondrial Myopathies; Muscle, Skeletal; Oxidation-Reduction; Rats; Submitochondrial Particles; Ubiquinone; Zidovudine

Topics: Exercise Test; Humans; Mitochondrial Myopathies; Phosphates; Phosphocreatine; Ubiquinone

We followed 16 patients with a variety of mitochondrial diseases over one to four periods of treatment (2 months each) with coenzyme Q10 plus vitamins K3 and C, riboflavin, thiamine, and niacin, using independent measures of oxidative metabolism to assess efficacy. There were large (> threefold) increases in serum coenzyme Q10 concentrations with treatment, but no measure of oxidative metabolism showed significant improvement with treatment for the group, nor did any individual patient show significant, reproducible, objective clinical improvement. The results suggest that coenzyme Q10 plus vitamin therapy does not significantly improve mitochondrial oxidative metabolism in patients with mitochondrial disease in general. Any clinical benefit that may follow from short-term administration appears slight.

Topics: Adenosine Triphosphate; Adolescent; Adult; Aged; Coenzymes; DNA, Mitochondrial; Gene Deletion; Humans; Lactates; Magnetic Resonance Spectroscopy; Middle Aged; Mitochondrial Myopathies; Muscles; Oxygen Consumption; Phosphates; Phosphocreatine; Physical Exertion; Point Mutation; Treatment Outcome; Ubiquinone; Vitamins