Caracterização da dinâmica mitocondrial na deficiência múltipla das acil-CoA desidrogenases

Mestrado em Bioquímica - Bioquímica ClínicaAs doenças da β-oxidação mitocondrial dos ácidos gordos fazem parte do painel de doenças detetadas no rastreio neonatal na grande maioria dos países desenvolvidos, incluindo Portugal. A deficiência múltipla das acil-CoA desidrogenases é uma das doenças rastreadas, sendo rara e apresentando um padrão de transmissão autossómico recessivo. Esta disfunção no metabolismo dos ácidos gordos é caracterizada por fenótipos bastante distintos, sendo reconhecidas duas formas clínicas: moderada e grave. Estudos anteriores do nosso grupo de investigação revelaram que o proteoma mitocondrial de pacientes homozigotos para a mesma mutação evidencia níveis de expressão diferentes das mesmas proteínas e que os pacientes com formas moderadas da doença apresentam semelhanças e diferenças quando comparados com pacientes com formas graves. O objetivo deste estudo foi relacionar as alterações dos processos biológicos associados à homeostasia mitocondrial com a severidade da doença, associada a mutações no gene que codifica a proteína electron transfer flavoprotein dehydrogenase (ETFDH), traçando semelhanças e diferenças. No geral, o nosso estudo fornece uma perspetiva global da dinâmica mitocondrial nas duas formas da doença. Ambas as formas, moderada e grave, apresentaram biogénese mitocondrial diminuída e adaptação metabólica, suportadas por níveis baixos de peroxisome proliferator-activated receptor γ coactivator 1 alpha (PGC-1α) e de gliceraldeído-3-fosfato desidrogenase (GAPDH), respetivamente, em todos os pacientes com a doença. Os níveis de expressão de sirtuina 3 (SIRT3) e a atividade de ATP sintase foram encontrados diminuídos em quase todos os pacientes, sugerindo uma disfunção mitocondrial. Os níveis reduzidos de SIRT3 foram corroborados pela diminuição dos níveis de PGC-1α. Os níveis de expressão das outras proteínas analisadas foram diversos entre os pacientes e, portanto, sugerem que a correlação entre a severidade da doença e as adaptações mitocondriais não é transversal a todas as formas da doença. De facto, os diferentes resultados obtidos podem explicar, pelo menos em parte, a variedade de fenótipos observados em pacientes com a doença. Neste sentido, são necessários mais estudos para compreender melhor a patogénese da doença. No futuro, seria interessante analisar os efeitos da deficiência de ETFDH noutras células em vez de fibroblastos e pesquisar outros metabolitos energéticos relacionados com estes mecanismos.Mitochondrial fatty acid β-oxidation disorders are some of the many diseases detected by newborn screening in most developed countries, including Portugal. Among screened disorders, multiple acyl-CoA dehydrogenase deficiency (MADD) is a rare autosomal recessively inherited disorder that presents very distinct phenotypes, being recognized in two clinical forms: mild and severe. Previous studies from our research group showed that the mitochondrial proteome of homozygous patients having the same mutation presents different expression levels of the same proteins and that patients with mild forms of MADD share some proteins with severe forms and at the same time present distinctive expression patterns. The aim of this study was to relate the regulation of biological processes associated to mitochondrial homeostasis with the severity of MADD, due to mutations on the gene that codifies the protein electron transfer flavoprotein dehydrogenase (ETFDH), evidencing similarities and differences. In overall our study provides a global perspective of the mitochondrial dynamics in the two forms of MADD, mild and severe. Both forms presented down-regulation of mitochondrial biogenesis and metabolic adaptation highlighted by lower levels of peroxisome proliferator-activated receptor γ coactivator 1 alpha (PGC-1α) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), respectively, in all MADD patients. Expression levels of sirtuin 3 (SIRT3) and the activity of ATP synthase were found decreased in almost all patients, suggesting mitochondrial dysfunction. Down-regulation of SIRT3 was corroborated by decreased levels of PGC-1α. The expression levels of the other proteins analyzed were diverse among MADD patients and thus highlighting no straight full correlation between disease severity and mitochondrial adaptations. In fact, the different results obtained may explain, at least in part, the variety of phenotypes observed in MADD patients. So, more studies are needed to better understand MADD pathogenesis. In the future, it would be interesting to analyze the effects of ETFDH deficiency in other cell types rather than fibroblasts and search for other energetic metabolites related with these mechanisms

Multimodal Image Analysis in Acquired Vitelliform Lesions and Adult-Onset Foveomacular Vitelliform Dystrophy

Purpose. To characterize vitelliform lesions (VLs) in adult-onset foveomacular vitelliform dystrophy (AOFVD) and acquired vitelliform (AVL) patients using multimodal image analysis. Methods. Retrospective study of twenty-eight eyes from nineteen patients diagnosed with AVL or AOFVD. They were evaluated by color fundus photographs, fundus autofluorescence (FAF), fluorescein angiography (FA), and spectral-domain optical coherence tomography (SD-OCT). Results. Bilateral VLs were associated with AOFVD (p=0.013). Regular and centered VLs were associated with AOFVD (p=0.004 and p=0.016), whereas irregular and noncentered lesions were more frequent in AVL patients. Visual acuity, greatest linear dimension (GLD), lesion height (LH), and pseudohypopyon were similar between groups. Whereas median LH and GLD in AVL group diminished significantly during follow-up (p=0.009 and p=0.001), AOFVD lesions tended to become larger and thicker. Conclusions. When consulting a patient presenting a VL with unknown age of onset, familial history, or previous retinal diseases, some aspects of multimodal imaging assessment may lead the ophthalmologist to a correct diagnosis

Exploring the aging effect of the anticancer drugs doxorubicin and mitoxantrone on cardiac mitochondrial proteome using a murine model

Current cancer therapies are successfully increasing the lifespan of cancer patients. Nevertheless, cardiotoxicity is a serious chemotherapy-induced adverse side effect. Doxorubicin (DOX) and mitoxantrone (MTX) are cardiotoxic anticancer agents, whose toxicological mechanisms are still to be identified. This study focused on DOX and MTX's cardiac mitochondrial damage and their molecular mechanisms. As a hypothesis, we also sought to compare the cardiac modulation caused by 9 mg/kg of DOX or 6 mg/kg of MTX in young adult mice (3 months old) with old control mice (aged control, 18-20 months old) to determine if DOX- and MTX-induced damage had common links with the aging process. Cardiac homogenates and enriched mitochondrial fractions were prepared from treated and control animals and analyzed by immunoblotting and enzymatic assays. Enriched mitochondrial fractions were also characterized by mass spectrometry-based proteomics. Data obtained showed a decrease in mitochondrial density in young adults treated with DOX or MTX and aged control, as assessed by citrate synthase (CS) activity. Furthermore, aged control had increased expression of the peroxisome proliferator-activated receptor γ coactivator 1 α (PGC1α) and manganese superoxide dismutase (MnSOD). Regarding the enriched mitochondrial fractions, DOX and MTX led to downregulation of proteins related to oxidative phosphorylation, fatty acid oxidation, amino acid metabolic process, and tricarboxylic acid cycle. MTX had a greater impact on malate dehydrogenase (MDH2) and pyruvate dehydrogenase E1 component subunit α (PDHA1). No significant proteomic changes were observed in the enriched mitochondrial fractions of aged control when compared to young control. To conclude, DOX and MTX promoted changes in several mitochondrial-related proteins in young adult mice, but none resembling the aged phenotype.publishe

Portuguese guide lines for the use of biological agents in rheumatoid arthritis - october 2011 update

The authors present the revised version of the Portuguese Society of Rheumatology (SPR) guidelines for the treatment of Rheumatoid Arthritis (RA) with biological therapies. In these guidelines the criteria for introduction and maintenance of biological agents are discussed as well as the contraindications and procedures in the case of non-responders. Biological treatment (with a tumour necrosis factor antagonist, abatacept or tocilizumab) should be considered in RA patients with a disease activity score 28 (DAS 28) equal to or greater than 3.2 des pite treatment with at least 20mg-weekly-dose of methotrexate (MTX) for at least 3 months or, if such treatment is not possible, after 3 months of other conventional disease modifying drug or combination therapy. A DAS 28 score between 2.6 and 3.2 with a significant functional or radiological deterioration under treatment with conventional regi -mens could also constitute an indication for biological treatment. The treatment goal should be remission or, if that is not achievable, at least a low disease activity, defined by a DAS28 lower than 3.2,without significative functional or radiological worsening. The response criteria, at the end of the first 3 months of treatment, are a decrease of at least 0.6 in the DAS28 score. After 6 months of treatment res ponse criteria is defined as a decrease greater than 1.2 in the DAS28 score. Non-responders, in accordance to the Rheumatologist's clinical opi -nion, should try a switch to another biological agent (tumour necrosis factor antagonist, abatacept, rituxi mab or tocilizumab).publishersversionpublishe

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans—anteaters, sloths, and armadillos—have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, 10 anteaters, and 6 sloths. Our data set includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the southern United States, Mexico, and Caribbean countries at the northern portion of the Neotropics, to the austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n = 5,941), and Cyclopes sp. have the fewest (n = 240). The armadillo species with the most data is Dasypus novemcinctus (n = 11,588), and the fewest data are recorded for Calyptophractus retusus (n = 33). With regard to sloth species, Bradypus variegatus has the most records (n = 962), and Bradypus pygmaeus has the fewest (n = 12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other data sets of Neotropical Series that will become available very soon (i.e., Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans data set. Please cite this data paper when using its data in publications. We also request that researchers and teachers inform us of how they are using these data