RESUMO
Migraine is a primary headache with high prevalence in the general population but is considered a disabling medical condition. It is suggested that obesity is a risk factor for chronic migraine. Thus treatment with drugs, such as topiramate, which reduces pain and weight, is ideal for obese patients with migraine. The aim of this study was to evaluate the effects of topiramate on body composition in patients with chronic migraine and to verify whether these effects could be related to nutritional status. We studied 26 female patients with age ranging from 18 to 45 years with prophylactic treatment with topiramate (50 mg/day) for three months. Body composition indexes (body mass index, BMI; body fat, BF; fat-free mass, FFM) were obtained through anthropometric assessment. After treatment, topiramate reduced BMI (0,82 kg/m2) and in BF (3.3 %), but increased FFM (1.1 kg). When considering nutritional status, FFM was increased only in obese patients. In conclusion, our main finding is that besides the reduction in BMI and BF, topiramate led to an increase in FFM in overweight and obese patients. Our results open new perspectives for future studies on the relationship between body composition and migraine, indicating that more studies on this body compartment are needed, especially in patients with chronic migraine.
RESUMO
L-Arginine (L-ARG) supplementation has been suggested as a therapeutic option in several diseases, including Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like syndrome (MELAS), arguably the most common mitochondrial disease. It is suggested that L-ARG, a nitric oxide (NO) precursor, can restore NO levels in blood vessels, improving cerebral blood flow. However, NO also participates in mitochondrial processes, such as mitochondrial biogenesis, the regulation of the respiratory chain, and oxidative stress. This study investigated the effects of L-ARG on mitochondrial function, nitric oxide synthesis, and nitro-oxidative stress in cell lines harboring the MELAS mitochondrial DNA (mtDNA) mutation (m.3243A>G). We evaluated mitochondrial enzyme activity, mitochondrial mass, NO concentration, and nitro-oxidative stress. Our results showed that m.3243A>G cells had increased NO levels and protein nitration at basal conditions. Treatment with L-ARG did not affect the mitochondrial function and mass but reduced the intracellular NO concentration and nitrated proteins in m.3243A>G cells. The same treatment led to opposite effects in control cells. In conclusion, we showed that the main effect of L-ARG was on protein nitration. Lowering protein nitration is probably involved in the mechanism related to L-ARG supplementation benefits in MELAS patients.
Assuntos
Arginina/farmacologia , DNA Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Doenças Mitocondriais/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Linhagem Celular , Humanos , Doenças Mitocondriais/genética , Mutação , Óxido Nítrico/biossínteseRESUMO
Purpose: The photopic negative response (PhNR) is an electrophysiological method that provides retinal ganglion cell function assessment using full-field stimulation that does not require clear optics or refractive correction. The purpose of this study was to assess ganglion cell function by PhNR in affected and asymptomatic carriers from Brazilian families with LHON. Methods: Individuals either under suspicion or previously diagnosed with LHON and their family members were invited to participate in this cross-sectional study. Screening for the most frequent LHON mtDNA mutations was performed. Visual acuity, color discrimination, visual fields, pattern-reversal visual evoked potentials (PRVEP), full-field electroretinography and PhNR were tested. A control group of healthy subjects was included. Full-field ERG PhNR were recorded using red (640 nm) flashes at 1 cd.s/m2, on blue (470 nm) rod saturating background. PhNR amplitude (µV) was measured using baseline-to-trough (BT). Optical coherence tomography scans of both the retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) were measured. PhNR amplitudes among affected, carriers and controls were compared by Kruskal-Wallis test followed by post-hoc Dunn test. The associations between PhNR amplitude and OCT parameters were analyzed by Spearman rank correlation. Results: Participants were 24 LHON affected patients (23 males, mean age=30.5 ± 11.4 yrs) from 19 families with the following genotype: m.11778G>A [N = 15 (62%), 14 males]; m.14484T>C [N = 5 (21%), all males] and m.3460G>A [N = 4 (17%), all males] and 14 carriers [13 females, mean age: 43.2 ± 13.3 yrs; m.11778G>A (N = 11); m.3460G>A (N = 2) and m.14484T>C (N = 1)]. Controls were eight females and seven males (mean age: 32.6 ± 11.5 yrs). PhNR amplitudes were significantly reduced (p = 0.0001) in LHON affected (-5.96 ± 3.37 µV) compared to carriers (-16.53 ± 3.40 µV) and controls (-23.91 ± 4.83; p < 0.0001) and in carriers compared to controls (p = 0.01). A significant negative correlation was found between PhNR amplitude and total macular ganglion cell thickness (r = -0.62, p < 0.05). Severe abnormalities in color discrimination, visual fields and PRVEPs were found in affected and subclinical abnormalities in carriers. Conclusions: In this cohort of Brazilian families with LHON the photopic negative response was severely reduced in affected patients and mildly reduced in asymptomatic carriers suggesting possible subclinical abnormalities in the latter. These findings were similar among pathogenic mutations.
RESUMO
Nitric oxide (NO) is an important signaling messenger involved in different mitochondrial processes but only few studies explored the participation of NO in mitochondrial abnormalities found in patients with genetic mitochondrial deficiencies. In this study we verified whether NO synthase (NOS) activity was altered in different types of mitochondrial abnormalities and whether changes in mitochondrial function and NOS activity could be associated with the induction of apoptosis. We performed a quantitative and integrated analysis of NOS activity in individual muscle fibres of patients with mitochondrial diseases, considering mitochondrial function (cytochrome-c-oxidase activity), mitochondrial content, mitochondrial DNA mutation and presence of apoptotic nuclei. Our results indicated that sarcolemmal NOS activity was increased in muscle fibres with mitochondrial proliferation, supporting the relevance of neuronal NOS in the mitochondrial biogenesis process. Sarcoplasmic NOS activity was reduced in cytochrome-c-oxidase deficient fibres, probably as a consequence of the involvement of NO in the regulation of the respiratory chain. Alterations in NOS activity or mitochondrial abnormalities were not predisposing factors to apoptotic nuclei. Taken together, our results show that NO can be considered a potential molecular target for strategies to increase mitochondrial content and indicate that this approach may not be associated with increased apoptotic events.
Assuntos
Apoptose , Mitocôndrias Musculares/metabolismo , Doenças Mitocondriais/metabolismo , Dinâmica Mitocondrial , Fibras Musculares Esqueléticas/metabolismo , Óxido Nítrico/biossíntese , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mitocôndrias Musculares/genética , Mitocôndrias Musculares/patologia , Doenças Mitocondriais/genética , Doenças Mitocondriais/patologia , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Fibras Musculares Esqueléticas/patologia , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Óxido Nítrico/genética , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase/metabolismoRESUMO
The diagnosis of mitochondrial encephalomyopathies caused by complex I (C-I) deficiency relies mainly on the spectrophotometric C-I assay. Considered difficult, this assay lacks reliability and has high nonspecific activity. We studied the key factors of this assay in cultured cells (cybrid and fibroblast): ubiquinone analogues, rotenone inhibition to determine specific activity, and mode of permeabilization of mitochondrial membranes. We showed that ubiquinone 1 allows a more stable and reliable assay, better results were obtained with rotenone inhibition done in the same assay, and mitochondrial permeability was improved just by freeze/thawing the sample prior to the assay.
Assuntos
Complexo I de Transporte de Elétrons/metabolismo , Espectrofotometria/métodos , Células Cultivadas , Ensaios Enzimáticos/métodos , Fibroblastos/metabolismo , Humanos , Mitocôndrias/metabolismo , Ubiquinona/análogos & derivados , Ubiquinona/metabolismoRESUMO
Nitric oxide (NO) has been implicated in several cellular processes as a signaling molecule and also as a source of reactive nitrogen species (RNS). NO is produced by three isoenzymes called nitric oxide synthases (NOS), all present in skeletal muscle. While neuronal NOS (nNOS) and endothelial NOS (eNOS) are isoforms constitutively expressed, inducible NOS (iNOS) is mainly expressed during inflammatory responses. Recent studies have demonstrated that NO is also involved in the mitochondrial biogenesis pathway, having PGC-1α as the main signaling molecule. Increased NO synthesis has been demonstrated in the sarcolemma of skeletal muscle fiber and NO can also reversibly inhibit cytochrome c oxidase (Complex IV of the respiratory chain). Investigation on cultured skeletal myotubes treated with NO donors, NO precursors or NOS inhibitors have also showed a bimodal effect of NO that depends on the concentration used. The present review will discuss the new insights on NO roles on mitochondrial biogenesis and function in skeletal muscle. We will also focus on potential therapeutic strategies based on NO precursors or analogs to treat patients with myopathies and mitochondrial deficiency.
Assuntos
Mitocôndrias Musculares/metabolismo , Renovação Mitocondrial/fisiologia , Músculo Esquelético/metabolismo , Óxido Nítrico/metabolismo , Animais , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Humanos , Músculo Esquelético/citologia , Óxido Nítrico Sintase/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Fatores de Transcrição/metabolismoRESUMO
We identified a double mutation in a patient with chronic progressive external ophthalmoplegia, located in the tRNA(Ala) (m.5628T>C) and tRNA(Lys) (m.8348A>G) genes. Both mutations were previously described separately and considered pathogenic, however the same mutations were also reported as polymorphisms or phenotype modulator. We analyzed the proportion of each mutation in isolated muscle fibers by single fiber-polymerase chain reaction to investigate the contribution of each mutation to mitochondrial deficiency. Our findings demonstrated that the mutations were heteroplasmic in skeletal muscle and both mutations were present in all single muscle fibers. The proportions of the m.5628T>C mutation were not significantly different between normal and cytochrome-c-oxidase (COX) deficient fibers. However, a significant higher proportion of the m.8348A>G mutation was observed in COX deficient fibers. Homoplasmic m.8348A>G was only observed in COX negative fibers. In conclusion, we provide a piece of evidence toward the pathogenicity of the m.8348A>G mutation and suggest that m.5628T>C is probably a neutral polymorphism.
Assuntos
Fibras Musculares Esqueléticas/metabolismo , Oftalmoplegia Externa Progressiva Crônica/genética , Mutação Puntual/genética , RNA de Transferência de Alanina/genética , RNA de Transferência de Lisina/genética , Adulto , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Feminino , Humanos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Oftalmoplegia Externa Progressiva Crônica/metabolismoAssuntos
Infarto Cerebral/etiologia , Hemiplegia/etiologia , Transtornos de Enxaqueca/complicações , Infarto Cerebral/diagnóstico , Infarto Cerebral/genética , Criança , Hemiplegia/diagnóstico , Hemiplegia/genética , Humanos , Imageamento por Ressonância Magnética , Masculino , Transtornos de Enxaqueca/diagnóstico , Transtornos de Enxaqueca/genéticaAssuntos
Criança , Humanos , Masculino , Infarto Cerebral/etiologia , Hemiplegia/etiologia , Transtornos de Enxaqueca/complicações , Infarto Cerebral/diagnóstico , Infarto Cerebral/genética , Hemiplegia/diagnóstico , Hemiplegia/genética , Imageamento por Ressonância Magnética , Transtornos de Enxaqueca/diagnóstico , Transtornos de Enxaqueca/genéticaRESUMO
Mitochondrial abnormalities have been associated with several aspects of epileptogenesis, such as energy generation, control of cell death, neurotransmitter synthesis, and free radical (FR) production. Increased production of FRs may cause mtDNA damage leading to decreased activities of oxidative phosphorylation complexes containing mtDNA-encoded subunits. In this study, we investigated whether increased generation of FR during status epilepticus would be sufficient to provoke abnormalities in mtDNA and in the expression and activity of cytochrome c oxidase (CCO), complex IV of the respiratory chain, in the chronic phase of the pilocarpine model of temporal lobe epilepsy. DNA analysis revealed low amounts of a 4.8 kb mtDNA deletion but with no differences in frequency or quantity in the control and experimental groups. We did not find abnormalities in the expression and distribution of an mtDNA-encoded subunit of CCO (CCO-I) or a relative decrease in CCO-I when compared with nuclear-encoded subunits (CCO-IV and SDH-fp). No abnormality in CCO activity was observed through histochemistry. Although evidences of mitochondrial abnormalities were found in previously published studies, our results do not suggest that the FRs, generated during the acute phase, determined important abnormalities in mtDNA, in expression of CCO-I, and in CCO activity.