RESUMEN
Semiconducting single walled carbon nanotubes (SWCNTs) are promising materials for biosensing applications with electrolyte-gated transistors (EGT). However, to be employed in EGT devices, SWCNTs often require lengthy solution-processing fabrication techniques. Here, we introduce a simple solution-based method that allows fabricating EGT devices from stable dispersions of SWCNTs/bovine serum albumin (BSA) hybrids in water. The dispersion is then deposited on a substrate allowing the formation of a SWCNTs random network as the semiconducting channel. We demonstrate that this methodology allows the fabrication of EGT devices with electric performances that allow their use in biosensing applications. We demonstrate their application for the detection of cortisol in solution, upon gate electrode functionalization with anti-cortisol antibodies. This is a robust and cost-effective methodology that sets the ground for a SWCNT/BSA-based biosensing platform that allows overcoming many limitations of standard SWCNTs biosensor fabrications.
Asunto(s)
Técnicas Biosensibles , Nanotubos de Carbono , Albúmina Sérica Bovina , Técnicas Biosensibles/métodos , ElectrólitosRESUMEN
The Met80Ala variant of yeast cytochrome c is known to possess electrocatalytic properties that are absent in the wild type form and that make it a promising candidate for biocatalysis and biosensing. The versatility of an enzyme is enhanced by the stability in mixed aqueous/organic solvents that would allow poorly water-soluble substrates to be targeted. In this work, we have evaluated the effect of dimethylsulfoxide (DMSO) on the functionality of the Met80Ala cytochrome c mutant, by investigating the thermodynamics and kinetics of electron transfer in mixed water/DMSO solutions up to 50% DMSO v/v. In parallel, we have monitored spectroscopically the retention of the main structural features in the same medium, focusing on both the overall protein structure and the heme center. We found that the organic solvent exerts only minor effects on the redox and structural properties of the mutant mostly as a result of the modification of the dielectric constant of the solvent. This would warrant proper functionality of this variant also under these potentially hostile experimental conditions, that differ from the physiological milieu of cytochrome c.
Asunto(s)
Citocromos c , Dimetilsulfóxido , Citocromos c/metabolismo , Dimetilsulfóxido/química , Cinética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Solventes , Termodinámica , AguaRESUMEN
The thermodynamic and kinetic properties for heterogeneous electron transfer (ET) were measured for the electrode-immobilized small laccase (SLAC) from Streptomyces coelicolor subjected to different electrostatic and covalent protein-electrode linkages, using cyclic voltammetry. Once immobilized electrostatically onto a gold electrode using mixed carboxyl- and hydroxy-terminated alkane-thiolate SAMs or covalently exploiting the same SAM subjected to N-hydroxysuccinimide+1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (NHS-EDC) chemistry, the SLAC-electrode electron flow occurs through the T1 center. The E°' values (from +0.2 to +0.1 V vs. SHE at pH 7.0) are lower by more than 0.2 V compared to the protein either in solution or immobilized with different anchoring strategies using uncharged SAMs. For the present electrostatic and covalent binding, this effect can, respectively, be ascribed to the negative charge of the SAM surfaces and to deletion of the positive charge of Lys/Arg residues due to amide bond formation which both selectively stabilize the more positively charged oxidized SLAC. Observation of enthalpy/entropy compensation within the series indicates that the immobilized proteins experience different reduction-induced solvent reorganization effects. The E°' values for the covalently attached SLAC are sensitive to three acid base equilibria, with apparent pKa values of pKa1ox = 5.1, pKa1red = 7.5, pKa2ox = 8.4, pKa2red = 10.9, pKa2ox = 8.9, pKa2red = 11.3 possibly involving one residue close to the T1 center and two residues (Lys and/or Arg) along with moderate protein unfolding, respectively. Therefore, the E°' value of immobilized SLAC turns out to be particularly sensitive to the anchoring mode and medium conditions.
Asunto(s)
Lacasa , Streptomyces coelicolor , Lacasa/química , Cinética , Electrones , Electrodos , TermodinámicaRESUMEN
Cytochrome c is a small globular protein whose main physiological role is to shuttle electrons within the mitochondrial electron transport chain. This protein has been widely investigated, especially as a paradigmatic system for understanding the fundamental aspects of biological electron transfer and protein folding. Nevertheless, cytochrome c can also be endowed with a non-native catalytic activity and be immobilized on an electrode surface for the development of third generation biosensors. Here, an overview is offered of the most significant examples of such a functional transformation, carried out by either point mutation(s) or controlled unfolding. The latter can be induced chemically or upon protein immobilization on hydrophobic self-assembled monolayers. We critically discuss the potential held by these systems as core constituents of amperometric biosensors, along with the issues that need to be addressed to optimize their applicability and response.
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Técnicas Biosensibles , Electrones , Proteínas/metabolismo , Electroquímica , Oxidación-Reducción , Mutación Puntual/genética , Pliegue de Proteína , Proteínas/química , Proteínas/genéticaRESUMEN
Congenital myopathies are typically characterised by early onset hypotonia, weakness and hallmark features on biopsy. Despite the rapid pace of gene discovery, â¼50% of patients with a congenital myopathy remain without a genetic diagnosis following screening of known disease genes. We performed exome sequencing on two consanguineous probands diagnosed with a congenital myopathy and muscle biopsy showing selective atrophy/hypotrophy or absence of type II myofibres. We identified variants in the gene (MYL1) encoding the skeletal muscle fast-twitch specific myosin essential light chain (ELC) in both probands. A homozygous essential splice acceptor variant (c.479-2A > G, predicted to result in skipping of exon 5 was identified in Proband 1, and a homozygous missense substitution (c.488T>G, p.(Met163Arg)) was identified in Proband 2. Protein modelling of the p.(Met163Arg) substitution predicted it might impede intermolecular interactions that facilitate binding to the IQ domain of myosin heavy chain, thus likely impacting on the structure and functioning of the myosin motor. MYL1 was markedly reduced in skeletal muscle from both probands, suggesting that the missense substitution likely results in an unstable protein. Knock down of myl1 in zebrafish resulted in abnormal morphology, disrupted muscle structure and impaired touch-evoked escape responses, thus confirming that skeletal muscle fast-twitch specific myosin ELC is critical for myofibre development and function. Our data implicate MYL1 as a crucial protein for adequate skeletal muscle function and that MYL1 deficiency is associated with severe congenital myopathy.
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Músculo Esquelético/fisiopatología , Cadenas Ligeras de Miosina/genética , Miotonía Congénita/genética , Alelos , Animales , Consanguinidad , Modelos Animales de Enfermedad , Exoma/genética , Homocigoto , Humanos , Masculino , Músculo Esquelético/metabolismo , Mutación , Cadenas Pesadas de Miosina/genética , Miotonía Congénita/fisiopatología , Linaje , Pez Cebra/genéticaRESUMEN
Electrolyte gated organic transistors can operate as powerful ultrasensitive biosensors, and efforts are currently devoted to devising strategies for reducing the contribution of hardly avoidable, nonspecific interactions to their response, to ultimately harness selectivity in the detection process. We report a novel lab-on-a-chip device integrating a multigate electrolyte gated organic field-effect transistor (EGOFET) with a 6.5 µL microfluidics set up capable to provide an assessment of both the response reproducibility, by enabling measurement in triplicate, and of the device selectivity through the presence of an internal reference electrode. As proof-of-concept, we demonstrate the efficient operation of our pentacene based EGOFET sensing platform through the quantification of tumor necrosis factor alpha with a detection limit as low as 3 pM. Sensing of inflammatory cytokines, which also include TNFα, is of the outmost importance for monitoring a large number of diseases. The multiplexable organic electronic lab-on-chip provides a statistically solid, reliable, and selective response on microliters sample volumes on the minutes time scale, thus matching the relevant key-performance indicators required in point-of-care diagnostics.
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Técnicas Biosensibles/métodos , Factor de Necrosis Tumoral alfa/análisis , Aptámeros de Péptidos/química , Aptámeros de Péptidos/metabolismo , Infecciones Bacterianas/metabolismo , Infecciones Bacterianas/patología , Técnicas Biosensibles/instrumentación , Electrodos , Oro/química , Humanos , Dispositivos Laboratorio en un Chip , Límite de Detección , Transistores Electrónicos , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
The interaction of cytochrome c with cardiolipin (CL) is a critical step in the initial stages of apoptosis and is mediated by a positively charged region on the protein surface comprising several lysine residues (site A). Here, the interaction of wt S. cerevisiae cytochrome c (ycc) and its K72A/K73A, K72A/K79A, K73A/K79A and K72A/K73A/K79A variants with CL was studied through UV-Vis and MCD spectroscopies at pH 7 and molecular dynamics (MD) simulations, to clarify the role of the mutated lysines. Moreover, the influence of the lipid to protein ratio on the interaction mechanism was investigated using low (0.5-10) and high (5-60) CL/ycc molar ratios, obtained with small and gradual or large and abrupt CL additions, respectively. Although all proteins bind to CL, switching from the native low-spin His/Met-ligated form to a low-spin bis-His conformer and to a high-spin species at larger CL concentrations, the two schemes of CL addition show relevant differences in the CL/ycc molar ratios at which the various conformers appear, due to differences in the interaction mechanism. Extended lipid anchorage and peripheral binding appear to prevail at low and high CL/ycc molar ratios, respectively. Simultaneous deletion of two or three surface positive charges from Site A does not abolish CL binding, but instead increases protein affinity for CL. MD calculations suggest this unexpected behavior results from the mutation-induced severe weakening of the H-bond connecting the Nε of His26 with the backbone oxygen of Glu44, which lowers the conformational stability compared to the wt species, overcoming the decreased surface electrostatic interaction.
Asunto(s)
Alanina/química , Cardiolipinas/química , Citocromos c/química , Lisina/química , Proteínas de Saccharomyces cerevisiae/química , Alanina/genética , Animales , Sitios de Unión , Bovinos , Citocromos c/genética , Corazón , Lisina/genética , Simulación de Dinámica Molecular , Estructura Molecular , Mutación , Proteínas de Saccharomyces cerevisiae/genética , Electricidad Estática , Propiedades de SuperficieRESUMEN
Lytic polysaccharide monooxygenases (LPMOs) are Cu-containing enzymes that facilitate the degradation of recalcitrant polysaccharides by the oxidative cleavage of glycosidic bonds. They are gaining rapidly increasing attention as key players in biomass conversion, especially for the production of second-generation biofuels. Elucidation of the detailed mechanism of the LPMO reaction is a major step toward the assessment and optimization of LPMO efficacy in industrial biotechnology, paving the way to utilization of sustainable fuel sources. Here, we used density functional theory calculations to study the reaction pathways suggested to date, exploiting a very large active-site model for a fungal AA9 LPMO and using a celloheptaose unit as a substrate mimic. We identify a copper oxyl intermediate as being responsible for H-atom abstraction from the substrate, followed by a rapid, water-assisted hydroxyl rebound, leading to substrate hydroxylation.
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Oxigenasas de Función Mixta/metabolismo , Neurospora crassa/enzimología , Polisacáridos/metabolismo , Teoría Cuántica , Biocatálisis , Oxigenasas de Función Mixta/química , Modelos Moleculares , Polisacáridos/químicaRESUMEN
Self-assembly is possibly the most effective and versatile strategy for surface functionalization. Self-assembled monolayers (SAMs) can be formed on (semi-)conductor and dielectric surfaces, and have been used in a variety of technological applications. This work aims to review the strategy behind the design and use of self-assembled monolayers in organic electronics, discuss the mechanism of interaction of SAMs in a microscopic device, and highlight the applications emerging from the integration of SAMs in an organic device. The possibility of performing surface chemistry tailoring with SAMs constitutes a versatile approach towards the tuning of the electronic and morphological properties of the interfaces relevant to the response of an organic electronic device. Functionalisation with SAMs is important not only for imparting stability to the device or enhancing its performance, as sought at the early stages of development of this field. SAM-functionalised organic devices give rise to completely new types of behavior that open unprecedented applications, such as ultra-sensitive label-free biosensors and SAM/organic transistors that can be used as robust experimental gauges for studying charge tunneling across SAMs.
RESUMEN
Lon protease is a nuclear-encoded, mitochondrial ATP-dependent protease highly conserved throughout the evolution, crucial for the maintenance of mitochondrial homeostasis. Lon acts as a chaperone of misfolded proteins, and is necessary for maintaining mitochondrial DNA. The impairment of these functions has a deep impact on mitochondrial functionality and morphology. An altered expression of Lon leads to a profound reprogramming of cell metabolism, with a switch from respiration to glycolysis, which is often observed in cancer cells. Mutations of Lon, which likely impair its chaperone properties, are at the basis of a genetic inherited disease named of the cerebral, ocular, dental, auricular, skeletal (CODAS) syndrome. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
Asunto(s)
Anomalías Craneofaciales/genética , ADN Mitocondrial/genética , Anomalías del Ojo/genética , Trastornos del Crecimiento/genética , Luxación Congénita de la Cadera/genética , Mitocondrias/enzimología , Chaperonas Moleculares/química , Mutación , Osteocondrodisplasias/genética , Proteasa La/química , Anomalías Dentarias/genética , Reprogramación Celular , Anomalías Craneofaciales/enzimología , Anomalías Craneofaciales/patología , ADN Mitocondrial/metabolismo , Anomalías del Ojo/enzimología , Anomalías del Ojo/patología , Trastornos del Crecimiento/enzimología , Trastornos del Crecimiento/patología , Luxación Congénita de la Cadera/enzimología , Luxación Congénita de la Cadera/patología , Homeostasis , Humanos , Mitocondrias/patología , Modelos Moleculares , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Osteocondrodisplasias/enzimología , Osteocondrodisplasias/patología , Proteasa La/genética , Proteasa La/metabolismo , Pliegue de Proteína , Anomalías Dentarias/enzimología , Anomalías Dentarias/patologíaRESUMEN
Neuroglobin (Ngb) is a recently identified hexa-coordinated globin, expressed in the nervous system of humans. Its physiological role is still debated: one hypothesis is that Ngb serves as an electron transfer (ET) species, possibly by reducing cytochrome c and preventing it to initiate the apoptotic cascade. Here, we use the perturbed matrix method (PMM), a mixed quantum mechanics/molecular dynamics approach, to investigate the redox thermodynamics of two neuroglobins, namely the human Ngb and GLB-6 from invertebrate Caenorhabditis elegans. In particular, we calculate the reduction potential of the two globins, resulting in an excellent agreement with the experimental values, and we predict the reorganization energies, λ, which have not been determined experimentally yet. The calculated λ values match well those reported for known ET proteins and thereby support a potential involvement in vivo of the two globins in ET processes.
Asunto(s)
Globinas/química , Simulación de Dinámica Molecular , Proteínas del Tejido Nervioso/química , Teoría Cuántica , Transporte de Electrón , Neuroglobina , TermodinámicaRESUMEN
Electronic coupling to electrodes, Γ, as well as that across the examined molecules, H, is critical for solid-state electron transport (ETp) across proteins. Assessing the importance of each of these couplings helps to understand the mechanism of electron flow across molecules. We provide here experimental evidence for the importance of both couplings for solid-state ETp across the electron-mediating protein cytochrome c (CytC), measured in a monolayer configuration. Currents via CytC are temperature-independent between 30 and â¼130 K, consistent with tunneling by superexchange, and thermally activated at higher temperatures, ascribed to steady-state hopping. Covalent protein-electrode binding significantly increases Γ, as currents across CytC mutants, bound covalently to the electrode via a cysteine thiolate, are higher than those through electrostatically adsorbed CytC. Covalent binding also reduces the thermal activation energy, Ea, of the ETp by more than a factor of two. The importance of H was examined by using a series of seven CytC mutants with cysteine residues at different surface positions, yielding distinct electrode-protein(-heme) orientations and separation distances. We find that, in general, mutants with electrode-proximal heme have lower Ea values (from high-temperature data) and higher conductance at low temperatures (in the temperature-independent regime) than those with a distal heme. We conclude that ETp across these mutants depends on the distance between the heme group and the top or bottom electrode, rather than on the total separation distance between electrodes (protein width).
Asunto(s)
Citocromos c/metabolismo , Conductividad Eléctrica , Electrodos , Transporte de Electrón/fisiología , Animales , Citocromos c/genética , Escherichia coli , Hemo/metabolismo , Caballos , Mutagénesis Sitio-Dirigida , Mutación/genética , Unión Proteica , TemperaturaRESUMEN
Biorecognition is a central event in biological processes in the living systems that is also widely exploited in technological and health applications. We demonstrate that the Electrolyte Gated Organic Field Effect Transistor (EGOFET) is an ultrasensitive and specific device that allows us to quantitatively assess the thermodynamics of biomolecular recognition between a human antibody and its antigen, namely, the inflammatory cytokine TNFα at the solid/liquid interface. The EGOFET biosensor exhibits a superexponential response at TNFα concentration below 1 nM with a minimum detection level of 100 pM. The sensitivity of the device depends on the analyte concentration, reaching a maximum in the range of clinically relevant TNFα concentrations when the EGOFET is operated in the subthreshold regime. At concentrations greater than 1 nM the response scales linearly with the concentration. The sensitivity and the dynamic range are both modulated by the gate voltage. These results are explained by establishing the correlation between the sensitivity and the density of states (DOS) of the organic semiconductor. Then, the superexponential response arises from the energy-dependence of the tail of the DOS of the HOMO level. From the gate voltage-dependent response, we extract the binding constant, as well as the changes of the surface charge and the effective capacitance accompanying biorecognition at the electrode surface. Finally, we demonstrate the detection of TNFα in human-plasma derived samples as an example for point-of-care application.
Asunto(s)
Técnicas Biosensibles/instrumentación , Transistores Electrónicos , Factor de Necrosis Tumoral alfa/sangre , Capacidad Eléctrica , Diseño de Equipo , Humanos , Dispositivos Laboratorio en un Chip , Semiconductores , TermodinámicaRESUMEN
BACKGROUND: The most appropriate management of recurrent glioblastoma is still controversial. In particular, the role of surgery at recurrence remains uncertain. PATIENTS & METHODS: From our Institutional data warehouse we analyzed 270 consecutive patients who received second surgery for recurrent glioblastoma, to assess survival after second surgery, and to evaluate prognostic factors. RESULTS: Complete resection was found in 128 (47.4%) and partial resection in 142 patients (52.6%). Median survival from second surgery was 11.4 months (95% CI: 10.0-12.7). Multivariate analysis showed that age (p = 0.001), MGMT methylation (p = 0.021) and extent of surgery (p < 0.001) are associated with better survival. CONCLUSION: A complete resection should be the goal for second resection and younger age and MGMT methylation status might be considered in the selection of patients.
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Neoplasias Encefálicas/patología , Neoplasias Encefálicas/cirugía , Glioblastoma/patología , Glioblastoma/cirugía , Adolescente , Adulto , Anciano , Biomarcadores de Tumor , Neoplasias Encefálicas/mortalidad , Terapia Combinada , Metilación de ADN , Metilasas de Modificación del ADN/genética , Enzimas Reparadoras del ADN/genética , Manejo de la Enfermedad , Femenino , Glioblastoma/mortalidad , Humanos , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia , Pronóstico , Retratamiento , Tomografía Computarizada por Rayos X , Resultado del Tratamiento , Proteínas Supresoras de Tumor/genética , Adulto JovenRESUMEN
Mitochondrial cytochrome c (cytc) plays an important role in programmed cell death upon binding to cardiolipin (CL), a negatively charged phospholipid of the inner mitochondrial membrane (IMM). Although this binding has been thoroughly investigated in solution, little is known on the nature and reactivity of the adduct (cytc-CL) immobilized at IMM. In this work, we have studied electrochemically cytc-CL immobilized on a hydrophobic self-assembled monolayer (SAM) of decane-1-thiol. This construct would reproduce the motional restriction and the nonpolar environment experienced by cytc-CL at IMM. Surface-enhanced resonance Raman (SERR) studies allowed the axial heme iron ligands to be identified, which were found to be oxidation state dependent and differ from those of cytc-CL in solution. In particular, immobilized cytc-CL experiences an equilibrium between a low-spin (LS) 6c His/His and a high-spin (HS) 5c His/- coordination states. The former prevails in the oxidized and the latter in the reduced form. Axial coordination of the ferric heme thus differs from the (LS) 6c His/Lys and (LS) 6c His/OH(-) states observed in solution. Moreover, a relevant finding is that the immobilized ferrous cytc-CL is able to catalytically reduce dioxygen, likely to superoxide ion. These findings indicate that restriction of motional freedom due to interaction with the membrane is an additional factor playing in the mechanism of cytc unfolding and cytc-mediated peroxidation functional to the apoptosis cascade.
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Cardiolipinas/metabolismo , Citocromos c/química , Citocromos c/metabolismo , Enzimas Inmovilizadas/química , Hemo/química , Oxígeno/química , Cardiolipinas/química , Citocromos c/genética , Electroquímica , Variación Genética , Oxidación-Reducción , Unión Proteica , Espectrometría RamanRESUMEN
The wide range of variability of the reduction potential (E(0)) of blue-copper proteins has been the subject of a large number of studies in the past several years. In particular, a series of azurin mutants have been recently rationally designed tuning E(0) over a very broad range (700 mV) without significantly altering the redox-active site [Marshall et al., Nature, 2009, 462, 113]. This clearly suggests that interactions outside the primary coordination sphere are relevant to determine E(0) in cupredoxins. However, the molecular determinants of the redox potential variability are still undisclosed. Here, by means of atomistic molecular dynamics simulations and hybrid quantum/classical calculations, the mechanisms that determine the E(0) shift of two azurin mutants with high potential shifts are unravelled. The reduction potentials of native azurin and of the mutants are calculated obtaining results in good agreement with the experiments. The analysis of the simulations reveals that only a small number of residues (including non-mutated ones) are relevant in determining the experimentally observed E(0) variation via site-specific, but diverse, mechanisms. These findings open the path to the rational design of new azurin mutants with different E(0).
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Azurina/química , Pseudomonas aeruginosa/química , Azurina/genética , Simulación de Dinámica Molecular , Oxidación-Reducción , Mutación Puntual , Pseudomonas aeruginosa/genética , Teoría CuánticaRESUMEN
Thermodynamic and dynamic properties of iso-1-cytochrome c covalently bound to a bare gold surface are here investigated by large scale atomistic simulations. The reduction potential of the protein for low and high surface concentrations is calculated showing a good agreement with experimental estimates. The origin of the dependence of the reduction potential on the surface concentration is investigated and is demonstrated to stem from the changing polarizability of the environment surrounding the protein, a mechanism reminiscent of crowding effects. Moreover, structural analyses are performed revealing relevant changes induced by the presence of the electrode on the dynamic properties of cytochrome c. In particular, one of the two cavities previously identified on the protein surface [Bortolotti et al. J. Am. Chem. Soc., 2012, 134, 13670], and that reversibly open in cytochrome c freely diffusing in solution, is found to be deformed when the protein is adsorbed on gold. This modification exemplifies a mechanism that potentially leads to changes in the protein properties by surface-induced modification of its dynamical behavior.
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Citocromos c/química , Proteínas de Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/química , Adsorción , Oro/química , Proteínas Inmovilizadas/química , Modelos Moleculares , Oxidación-Reducción , Propiedades de Superficie , TermodinámicaRESUMEN
A long-held dogma in neurosurgery is that parenchymal arteriovenous malformations (AVMs) are congenital. However, there is no strong evidence supporting this theory. An increasing number of documented cases of de novo formation of parenchymal AVMs cast doubt on their congenital nature and suggest that indeed the majority of these lesions may form after birth. Further evidence suggesting the postnatal development of parenchymal AVMs comes from the exceedingly rare diagnosis of these lesions in utero despite the widespread availability of high-resolution imaging modalities such as ultrasound and fetal MRI. The exact mechanism of AVM formation has yet to be elucidated, but most likely involves genetic susceptibility and environmental triggering factors. In this review, the authors report 2 cases of de novo AVM formation and analyze the evidence suggesting that they represent an acquired condition.
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Malformaciones Arteriovenosas/genética , Malformaciones Arteriovenosas/cirugía , Predisposición Genética a la Enfermedad/genética , Procedimientos Neuroquirúrgicos , Adulto , Animales , Malformaciones Arteriovenosas/diagnóstico , Femenino , Humanos , Angiografía por Resonancia Magnética , Imagen por Resonancia Magnética , Masculino , Persona de Mediana EdadRESUMEN
Carotid-cavernous fistulas (CCFs) are rare intracranial vascular malformations. Among the various classifications available, the most recently proposed highlights the strong correlation between venous drainage pattern and clinical presentation. We present the case of a woman in her 70s with a history of transient palsy of the fourth cranial nerve who presented with subacute cervical myelopathy, which was caused by a CCF with venous drainage into the peribulbar and perimedullary plexus.Given this atypical presentation of CCF and the diagnostic challenges it poses, we conducted a comprehensive PubMed search looking for CCFs presenting with cervical myelopathy and our results confirmed their rarity and allowed us to identify clinical elements that may help clinicians diagnose and manage this potentially treatable condition.
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Fístula del Seno Cavernoso de la Carótida , Vértebras Cervicales , Enfermedades de la Médula Espinal , Humanos , Femenino , Fístula del Seno Cavernoso de la Carótida/complicaciones , Fístula del Seno Cavernoso de la Carótida/diagnóstico , Fístula del Seno Cavernoso de la Carótida/terapia , Vértebras Cervicales/diagnóstico por imagen , Enfermedades de la Médula Espinal/diagnóstico por imagen , Enfermedades de la Médula Espinal/diagnóstico , Enfermedades de la Médula Espinal/complicaciones , Anciano , Imagen por Resonancia MagnéticaRESUMEN
Arteriovenous malformation of the brain (bAVM) is a vascular phenotype related to brain defective angiogenesis. Involved vessels show impaired expression of vascular differentiation markers resulting in the arteriolar to venule direct shunt. In order to clarify aberrant gene expression occurring in bAVM, here we describe results obtained by methylome analysis performed on endothelial cells (ECs) isolated from bAVM specimens, compared to human cerebral microvascular ECs. Results were validated by quantitative methylation-specific PCR and quantitative realtime-PCR. Differential methylation events occur in genes already linked to bAVM onset, as RBPJ and KRAS. However, among differentially methylated genes, we identified EPHB1 and several other loci involved in EC adhesion as well as in EC/vascular smooth muscle cell (VSMC) crosstalk, suggesting that only endothelial dysfunction might not be sufficient to trigger the bAVM phenotype. Moreover, aberrant methylation pattern was reported for many lncRNA genes targeting transcription factors expressed during neurovascular development. Among these, the YBX1 that was recently shown to target the arteridin coding gene. Finally, in addition to the conventional CpG methylation, we further considered the role of impaired CHG methylation, mainly occurring in brain at embryo stage. We showed as differentially CHG methylated genes are clustered in pathways related to EC homeostasis, as well as to VSMC-EC crosstalk, suggesting as impairment of this interaction plays a prominent role in loss of vascular differentiation, in bAVM phenotype.