ubiquinone and MELAS-Syndrome

Mitochondrial encephalomyopathy with lactic acidosis and stroke- like episodes (MELAS) syndrome is caused by mitochondrial respiratory chain dysfunction and oxidative phosphorylation disorder. It is a rare clinical metabolic disease involved with multiple systems.. A 22-year-old patient presented with limb convulsion accompanied by loss of consciousness, headache, partial blindness, blurred vision, and so on.. Brain magnetic resonance imaging showed a high-intensity area in bilateral occipital cortex, left parietal lobe and cerebellum on diffusion-weighted imaging. These focus did not distribute as vascular territory. The pathological examination of skeletal muscle revealed several succinate dehydrogenase reactive vessels with overreaction and increased content of lipid droplets in some muscle fibers. Genetic testing showed that the patient carried m.10158T>C mutation.. She was provided with traditional arginine hydrochloride therapy and orally medication of coenzyme Q (10 mg).. Mitochondrial DNA of blood and hair follicle of patient carried m.10158T>C mutation LESSONS:: For the suspected patients of MELAS syndrome, if the hot-spot mutation test is negative, more detection sites should be selected.

Topics: Acidosis, Lactic; Administration, Oral; Arginine; Awareness; Brain; DNA, Mitochondrial; Female; Humans; Magnetic Resonance Imaging; MELAS Syndrome; Micronutrients; Mitochondrial Encephalomyopathies; Muscle, Skeletal; Mutation; Stroke; Succinate Dehydrogenase; Ubiquinone; Young Adult

Topics: Coenzymes; Deafness; Diabetes Mellitus, Type 2; Diagnosis, Differential; DNA, Mitochondrial; Hypoglycemic Agents; Insulin; Insulin Secretion; MELAS Syndrome; Mitochondria; Mutation; Prognosis; Ubiquinone

Topics: Coenzymes; Diagnosis, Differential; DNA, Mitochondrial; Humans; MELAS Syndrome; Migraine Disorders; Mutation; Prognosis; RNA; RNA, Mitochondrial; RNA, Transfer; Thiamine; Ubiquinone

We evaluated the effect of coenzyme Q10 supplementation to two patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) by using noninvasive tissue oximetry with near-infrared spectra of hemoglobin from the quadriceps muscle during bicycle ergometer exercise. Patients showed distinct oxygen consumption patterns reflecting the defect in oxidative phosphorylation and the impairment in oxygen utilization during exercise. Based on the oxygen consumption pattern, we considered one patient as having severe mitochondrial disorder and another patient as having mild one. After coenzyme Q10 supplementation, the oxygen consumption pattern of the patient with the severe form shifted to the mild one, while that of the patient with mild form remained unchanged. The shift of the pattern to the mild form correlated well with reduction of the sum of the serum lactate and pyruvate content during exercise. Noninvasive tissue oximetry may be useful to evaluate the effect of coenzyme Q10 supplementation to patients with mitochondrial encephalomyopathy including MELAS.

Topics: Adolescent; Adult; Blood Volume; Exercise Test; Female; Humans; Male; MELAS Syndrome; Oximetry; Oxygen Consumption; Spectroscopy, Near-Infrared; 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

Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes, the most common maternally inherited mitochondrial disease, can present with a wide range of neurological manifestations including both central and peripheral nervous system involvement. The most frequent genetic mutation reported in mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes syndrome is A3243G in MT-TL1 gene. Stroke-like episodes, dementia, epilepsy, lactic acidemia, myopathy, recurrent headaches, hearing impairment, diabetes, and short stature constitute the known presentations in this syndrome. Among the abnormal involuntary movements in mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes syndrome, myoclonus is the commonest. Other movement disorders, including chorea, are rarely reported in this disorder.. A 14-year-old South Asian boy from rural Bengal (India), born of a second degree consanguineous marriage, with normal birth and development history, presented with abnormal brief jerky movements involving his trunk and limbs, with recurrent falls for 10 months. We present here a case of heteroplasmic mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes syndrome with A3251G mutation, in which the clinical picture was dominated by a host of involuntary abnormal movements including chorea-ballism, myoclonus, and oromandibular dystonia in a backdrop of cognitive decline, seizure, and stroke-like episode. A final diagnosis was established by muscle biopsy and genetic study. Haloperidol was administered to control the involuntary movements along with introduction of co-enzyme Q, besides symptomatic management for his focal seizures. Six months into follow-up his seizures and abnormal movements were controlled significantly with slight improvement of cognitive abilities.. The dominance of hyperkinetic movements in the clinical scenario and the finding of a point mutation A3251G in MT-TL1 gene make this a rare presentation.

Topics: Adolescent; Anti-Dyskinesia Agents; Chorea; DNA, Mitochondrial; Genetic Testing; Haloperidol; Humans; Male; MELAS Syndrome; Micronutrients; Point Mutation; Treatment Outcome; Ubiquinone

Mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) are thought to be rarely accompanied by macroangiopathy. We reported a case of MELAS that presented right distal internal carotid arterial (ICA) stenosis and reviewed 12 similar previously reported cases involving intracranial large blood vessels.. A 38-year-old man suffered from recurrent stroke-like episodes (SE) such as alternating hemiparesis (right lesion 3 years ago and current left lesion), cortical blindness and seizure for 3 years, and was previously misdiagnosed as cerebral infarction. Magnetic Resonance Angiography (MRA) and Digital Subtraction Angiography (DSA) revealed right distal ICA stenosis and sparse cortex blood vessels, which were related to the previous SE.. He was diagnosed by genetic screening (a mitochondrial DNA A3243G point mutation) and presence of high lactic acidosis (4.03 mmol/L), which rose to 7.8 mmol/L after exercise.. The patient received Coenzyme Q10, vitamin C, L-arginine for 2 weeks and valproic acid sodium (400 mg bid) to prevent seizures till now.. He is currently less active and intelligent than his peers, with occasional seizures, and needs family care.. Till date, there are 12 reported cases of MELAS combined with major cerebral arteries abnormalities including stenosis, dissection, occlusion, reversible vasoconstriction, aneurysms, and atherosclerosis. Hence, macroangiopathy in MELAS is not very rare. There is correlation between the affected vessels and the lesions in some cases, but not in others, which may increase the misdiagnosis rate. Hence, mitochondrial diseases cannot be excluded due to concurrent macroangiopathic lesions.

Topics: Acidosis, Lactic; Adult; Arginine; Ascorbic Acid; Carotid Stenosis; Humans; Male; MELAS Syndrome; Mitochondrial Encephalomyopathies; Point Mutation; Ubiquinone; Valproic Acid

Defects in complex I due to mutations in mitochondrial DNA are associated with clinical features ranging from single organ manifestation like Leber hereditary optic neuropathy (LHON) to multiorgan disorders like mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome. Specific mutations cause overlap syndromes combining several phenotypes, but the mechanisms of their biochemical effects are largely unknown. The m.3376G>A transition leading to p.E24K substitution in ND1 with LHON/MELAS phenotype was modeled here in a homologous position (NuoH-E36K) in the Escherichia coli enzyme and it almost totally abolished complex I activity. The more conservative mutation NuoH-E36Q resulted in higher apparent K(m) for ubiquinone and diminished inhibitor sensitivity. A NuoH homolog of the m.3865A>G transition, which has been found concomitantly in the overlap syndrome patient with the m.3376G>A, had only a minor effect. Consequences of a primary LHON-mutation m.3460G>A affecting the same extramembrane loop as the m.3376G>A substitution were also studied in the E. coli model and were found to be mild. The results indicate that the overlap syndrome-associated m.3376G>A transition in MTND1 is the pathogenic mutation and m.3865A>G transition has minor, if any, effect on presentation of the disease. The kinetic effects of the NuoH-E36Q mutation suggest its proximity to the putative ubiquinone binding domain in 49kD/PSST subunits. In all, m.3376G>A perturbs ubiquinone binding, a phenomenon found in LHON, and decreases the activity of fully assembled complex I as in MELAS.

Topics: Amino Acid Sequence; Animals; Electron Transport Complex I; Escherichia coli Proteins; Humans; MELAS Syndrome; Membrane Proteins; Mitochondria; Models, Biological; Molecular Sequence Data; Mutagenesis, Site-Directed; Mutation; NADH Dehydrogenase; Optic Atrophy, Hereditary, Leber; Protein Binding; Protein Subunits; Sequence Homology, Amino Acid; Ubiquinone

MELAS (mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes) is a mitochondrial disease most usually caused by point mutations in tRNA genes encoded by mitochondrial DNA (mtDNA). Approximately 80% of cases of MELAS syndrome are associated with a m.3243A > G mutation in the MT-TL1 gene, which encodes the mitochondrial tRNALeu (UUR). Currently, no effective treatments are available for this chronic progressive disorder. Treatment strategies in MELAS and other mitochondrial diseases consist of several drugs that diminish the deleterious effects of the abnormal respiratory chain function, reduce the presence of toxic agents or correct deficiencies in essential cofactors.. We evaluated the effectiveness of some common pharmacological agents that have been utilized in the treatment of MELAS, in yeast, fibroblast and cybrid models of the disease. The yeast model harbouring the A14G mutation in the mitochondrial tRNALeu(UUR) gene, which is equivalent to the A3243G mutation in humans, was used in the initial screening. Next, the most effective drugs that were able to rescue the respiratory deficiency in MELAS yeast mutants were tested in fibroblasts and cybrid models of MELAS disease.. According to our results, supplementation with riboflavin or coenzyme Q(10) effectively reversed the respiratory defect in MELAS yeast and improved the pathologic alterations in MELAS fibroblast and cybrid cell models.. Our results indicate that cell models have great potential for screening and validating the effects of novel drug candidates for MELAS treatment and presumably also for other diseases with mitochondrial impairment.

Topics: Autophagy; Cell Line; Cells, Cultured; Drug Evaluation, Preclinical; Fibroblasts; Genes, Mitochondrial; Humans; MELAS Syndrome; Models, Biological; Mutation; Reactive Oxygen Species; Riboflavin; RNA, Transfer, Leu; Saccharomyces cerevisiae; Ubiquinone

Mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) is a maternally-inherited multisystem disorder. Mitochondrial angiopathy mediated by nitric oxide, a metabolite of L-arginine, is among the proposed pathophysiologic mechanisms of stroke-like episodes (SLEs) in MELAS. There are very few reports on long-term prevention of SLEs with oral L-arginine and idebenone treatment in MELAS adult patients.. A 38-year-old patient with MELAS and SLEs was treated with oral L-arginine and idebenone for 27months. She remained free of attacks throughout the treatment period except when she stopped her treatment on two occasions during which she had recurrent cerebral metabolic attacks. The patient experienced no side effect of treatment with L-arginine and idebenone.. Our observation suggests long-term safety and potential benefit of oral L-arginine and idebenone in the prevention of recurrence of SLEs in adult MELAS patients.

Topics: Administration, Oral; Adult; Antioxidants; Arginine; Drug Combinations; Female; Humans; MELAS Syndrome; Stroke; Time Factors; Treatment Outcome; Ubiquinone

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is a mitochondrial disease most usually caused by point mutations in tRNA genes encoded by mtDNA. Here, we report on how this mutation affects mitochondrial function in primary fibroblast cultures established from 2 patients with MELAS who harbored the A3243G mutation. Both mitochondrial respiratory chain enzyme activities and coenzyme Q(10) (CoQ) levels were significantly decreased in MELAS fibroblasts. A similar decrease in mitochondrial membrane potential was found in intact MELAS fibroblasts. Mitochondrial dysfunction was associated with increased oxidative stress and the activation of mitochondrial permeability transition (MPT), which triggered the degradation of impaired mitochondria. Furthermore, we found defective autophagosome elimination in MELAS fibroblasts. Electron and fluorescence microscopy studies confirmed a massive degradation of mitochondria and accumulation of autophagosomes, suggesting mitophagy activation and deficient autophagic flux. Transmitochondrial cybrids harboring the A3243G mutation also showed CoQ deficiency and increased autophagy activity. All these abnormalities were partially restored by CoQ supplementation. Autophagy in MELAS fibroblasts was also abolished by treatment with antioxidants or cyclosporine, suggesting that both reactive oxygen species and MPT participate in this process. Furthermore, prevention of autophagy in MELAS fibroblasts resulted in apoptotic cell death, suggesting a protective role of autophagy in MELAS fibroblasts.

Topics: Autophagy; Autophagy-Related Protein 5; Base Sequence; Cells, Cultured; DNA Primers; DNA, Mitochondrial; Electron Transport; Fibroblasts; Gene Knockdown Techniques; Humans; MELAS Syndrome; Microtubule-Associated Proteins; Mitochondria; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Point Mutation; Reactive Oxygen Species; RNA, Small Interfering; RNA, Transfer, Leu; Ubiquinone

Although mitochondrial disease research in general is robust, adequate treatment of these life-threatening conditions has lagged, partly because of a persistence of clinical anecdotes as substitutes for scientifically and ethically rigorous clinical trials. Here I summarize the key lessons learned from some of the "first generation" of randomized controlled trials for genetic mitochondrial diseases and suggest how future trials may benefit from both past experience and exciting new resources available for patient-oriented research and training in this field.

Topics: Acidosis, Lactic; Animals; Dichloroacetic Acid; Financing, Government; Humans; MELAS Syndrome; Mitochondrial Diseases; Neglected Diseases; Randomized Controlled Trials as Topic; Rare Diseases; Societies, Medical; Ubiquinone; United States

The ND1 subunit gene of the mitochondrial NADH-ubiquinone oxidoreductase (complex I) is a hot spot for mutations causing Leber hereditary optic neuropathy and several mutations causing the mitochondrial encephalopathy, lactic acidosis and stroke-like episodes syndrome (MELAS). We have used Escherichia coli and Paracoccus denitrificans as model systems to study the effect of mutations 3946 and 3949, which change conserved residues in ND1 and cause MELAS. The vicinity of these mutations was also explored with a series of mutations in charged residues. The 3946 mutation results in E214K substitution in human ND1. Replacement of the equivalent residue in E. coli with lysine or glutamine detracted from enzyme assembly and the assembled enzyme was inactive. However, the equivalent E234Q mutant enzyme in P. denitrificans failed to assemble completely (or was rapidly degraded). Also the corresponding substitution with aspartate decreased the enzyme activity in P. denitrificans and E. coli. The 3949-equivalent substitution, Y229H in E. coli, lowered the catalytic activity by 30%. In addition, an activation of the enzyme during catalytic turnover was seen in this bacterial NDH-1, something that was even more pronounced in another mutant in the same loop, D213E. Several other mutations in this region decreased the enzyme activity. The studied MELAS mutations are situated in a matrix-side loop, which appears to be highly sensitive to structural perturbations. The results provide new information on the function of the region affected by the MELAS mutations 3946 and 3949 that is not obtainable from patient samples or current eukaryote models.

Topics: Amino Acid Sequence; Catalysis; Cell Membrane; Conserved Sequence; DNA, Mitochondrial; Electron Transport Complex I; Escherichia coli Proteins; Humans; MELAS Syndrome; Molecular Sequence Data; Paracoccus denitrificans; Point Mutation; Protein Subunits; Ubiquinone

Topics: Adult; C-Peptide; Diabetes Complications; Female; Gene Expression; Humans; Islets of Langerhans; MELAS Syndrome; Pancreatic Diseases; Point Mutation; Ubiquinone

Topics: Coenzymes; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; MELAS Syndrome; Middle Aged; Neurologic Examination; Ubiquinone

We report a patient with MELAS treated for 24 months with idebenone and riboflavin, during which no stroke-like episodes occurred. Moreover neurological symptoms clearly improved, and a recovery of brain MRI and EEG abnormalities was observed. We conclude that the combined treatment with idebenone and riboflavin may restore the metabolic impairment in MELAS, possibly improving the long-term prognosis in these patients.

Topics: Adult; Antioxidants; Aphasia, Wernicke; Benzoquinones; Cerebral Cortex; Cerebral Infarction; Drug Administration Schedule; Drug Therapy, Combination; Electron Transport; Humans; Magnetic Resonance Imaging; Male; MELAS Syndrome; Mitochondria; Photosensitizing Agents; Riboflavin; Treatment Outcome; Ubiquinone

We report a 36-year-old man with MELAS in whom a 5-month course of high-dose oral idebenone, a derivative of coenzyme Q10, increased markedly cerebral metabolic ratio of oxygen and oxygen extraction fraction without increased cerebral blood flow with PET. The results indicate that idebenone improves mitochondrial oxidative metabolism in the brain and suggest a therapeutic potential of idebenone for MELAS.

Topics: Adult; Benzoquinones; Brain; Humans; Magnetic Resonance Imaging; Male; MELAS Syndrome; Mitochondria; Tomography, Emission-Computed; Ubiquinone

We studied free radical, lipid peroxide (LPO) and antioxidant levels of blood in three cases with mitochondrial encephalomyopathy. Case 1 was a 17-year-old man with MELAS. Serum vitamin E levels were decreased and LPO levels were increased after stroke-like episodes in case 1. Case 2 was a 68-year-old woman with MELAS and a maternal elder aunt of case 1. She showed an elevated serum LPO levels (6.58 nmol/ml) in the absence of stroke-like episode and serum CoQ10 level was 0.54 microgram/ml before therapy. By CoQ10, idebenone and tocopherol nicotinate therapy, serum LPO levels decreased gradually in parallel with the decrease of lactate and pyruvate levels. Free radicals were measured in case 2 and controls by spin trapping method. Hydroxyl radical and C center radical were increased and H radical was normal in blood. But these free radicals in serum were all normal. Her serum antioxidants revealed an elevated percent inhibition of SOD and a decreased transfferin level. Case 3 was a 52-year-old woman with MERRF. She showed an elevation of serum LPO (12.8 nmol/ml). Her serum antioxidants revealed an elevated vitamin E and ceruloplasmin levels and percent inhibition of SOD.

Topics: Adolescent; Aged; Coenzymes; Female; Free Radicals; Humans; Lipid Peroxides; Male; MELAS Syndrome; MERRF Syndrome; Superoxide Dismutase; Ubiquinone; Vitamin E