Institute DAlta Tecnologia

Barcelona, Spain

Institute DAlta Tecnologia

Barcelona, Spain

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Rojas S.,Center dImatge Molecular | Herance J.R.,Center dImatge Molecular | Gispert J.D.,Institute dAlta Tecnologia | Abad S.,Center dImatge Molecular | And 8 more authors.
Neurobiology of Aging | Year: 2013

Positron emission tomography (PET) has been used extensively to evaluate the neuropathology of Alzheimer's disease (AD) in vivo. Radiotracers directed toward the amyloid deposition such as [18F]-FDDNP (2-(1-{6-[(2-[F]Fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile) and [11C]-PIB (Pittsburg compound B) have shown exceptional value in animal models and AD patients. Previously, the glucose analogue [18F]-FDG (2-[(18)F]fluorodeoxyglucose) allowed researchers and clinicians to evaluate the brain glucose consumption and proved its utility for the early diagnosis and the monitoring of the progression of AD. Animal models of AD are based on the transgenic expression of different human mutant genes linked to familial AD. The novel transgenic 5XFAD mouse containing 5 mutated genes in its genome has been proposed as an AD model with rapid and massive cerebral amyloid deposition. PET studies performed with animal-dedicated scanners indicate that PET with amyloid-targeted radiotracers can detect the pathological amyloid deposition in transgenic mice and rats. However, in other studies no differences were found between transgenic mice and their wild type littermates. We sought to investigate in 5XFAD mice if the radiotracers [11C]-PIB, and [18F]-Florbetapir could quantify the amyloid deposition in vivo and if [18F]-FDG could do so with regard to glucose consumption. We found that 5XFAD animals presented higher cerebral binding of [18F]-Florbetapir, [11C]-PIB, and [18F]-FDG. These results support the use of amyloid PET radiotracers for the evaluation of AD animal models. Probably, the increased uptake observed with [18F]-FDG is a consequence of glial activation that occurs in 5XFAD mice. © 2013 Elsevier Inc.

Abate-Daga D.,Institute DInvestigacions Biomediques August Pi i Sunyer IDIBAPS | Andreu N.,Research Center Biomedica En Red Of Enfermedades Raras Ciberer | Camacho-Sanchez J.,Lhospitalet Of Llobregat | Alemany R.,Lhospitalet Of Llobregat | And 4 more authors.
PLoS ONE | Year: 2011

Replication-competent adenoviruses armed with thymidine kinase (TK) combine the concepts of virotherapy and suicide gene therapy. Moreover TK-activity can be detected by noninvasive positron emission-computed tomography (PET) imaging, what could potentially facilitate virus monitoring in vivo. Here, we report the generation of a novel oncolytic adenovirus that incorporates the Tat8-TK gene under the control of the Major Late Promoter in a highly selective backbone thus providing selectivity by targeting the retinoblastoma pathway. The selective oncolytic TK virus, termed ICOVIR5-TK-L, showed reduced potency compared to a non-selective counterpart. However the combination of ICOVIR5-TK-L with ganciclovir (GCV) induced a potent antitumoural effect similar to that of wild type adenovirus in a preclinical model of pancreatic cancer. Although the treatment with GCV provoked a reduction in the viral yield, both in vitro and in vivo, a two-cycle treatment of virus and GCV resulted in an enhanced antitumoral response that correlated with high TK-activity, based on microPET measurements. Thus, TK-expressing oncolytic adenoviruses can be traced by PET imaging providing real time information on the activity of the virus and its antitumoral potency can be optimized by GCV dosing. © 2011 Abate-Daga et al.

Gironell A.,Autonomous University of Barcelona | Figueiras F.P.,Institute dAlta Tecnologia | Pagonabarraga J.,Autonomous University of Barcelona | Herance J.R.,Institute dAlta Tecnologia | And 2 more authors.
Parkinsonism and Related Disorders | Year: 2012

Background: Essential tremor is the most common movement disorder in adults, but its exact etiology and pathophysiology are still not fully understood. There is some consensus, however, about the involvement of the cerebellum and accumulating evidence points towards a dysfunction of the gabaergic system. We hypothesize that the serotonin neurotransmission system may also play a role as it does in tremor in Parkinson disease. This study aimed to investigate the association between the severity of tremor symptoms and the gabaergic and serotoninergic neurotransmission systems in essential tremor. Material and methods: We measured the tremor clinical rating scale score and acquired DASB and Flumazenil PET scans in 10 patients who presented with essential tremor at different stages of clinical severity. Statistically significant correlations were sought between the scale scores and parametric binding potential images. Results: The correlation analysis of cerebellar Flumazenil uptake and tremor clinical rating scale scores reached statistical significance (R2 = 0.423, p = 0.041), whereas no association was detected in the DASB scans. Conclusions: The severity of tremor correlated with the abnormalities found in GABA receptor binding, suggesting a primary gabaergic deficiency or a functional abnormality at the level of GABAA receptor subtypes. These results may assist in the rational development of new pharmacological treatments for essential tremor. © 2012 Elsevier Ltd.

Moreno-Torres A.,Center Diagnostic Pedralbes | Moreno-Torres A.,CIBER ISCIII | Rosset-Llobet J.,Institute Of Fisiologia I Medicina Of Lart | Pujol J.,Institute dAlta Tecnologia | And 3 more authors.
PLoS ONE | Year: 2010

Background: Although non-specific pain in the upper limb muscles of workers engaged in mild repetitive tasks is a common occupational health problem, much is unknown about the associated structural and biochemical changes. In this study, we compared the muscle energy metabolism of the extrinsic finger extensor musculature in instrumentalists suffering from work-related pain with that of healthy control instrumentalists using non-invasive phosphorus magnetic resonance spectroscopy (31P-MRS). We hypothesize that the affected muscles will show alterations related with an impaired energy metabolism. Methodology/Principal Findings:We studied 19 volunteer instrumentalists (11 subjects with work-related pain affecting the extrinsic finger extensor musculature and 8 healthy controls). We used 31P-MRS to find deviations from the expected metabolic response to exercise in phosphocreatine (PCr), inorganic phosphate (Pi), Pi/PCr ratio and intracellular pH kinetics. We observed a reduced finger extensor exercise tolerance in instrumentalists with myalgia, an intracellular pH compartmentation in the form of neutral and acid compartments, as detected by Pi peak splitting in 31P-MRS spectra, predominantly in myalgic muscles, and a strong association of this pattern with the condition. Conclusions/Significance: Work-related pain in the finger extrinsic extensor muscles is associated with intracellular pH compartmentation during exercise, non-invasively detectable by 31P-MRS and consistent with the simultaneous energy production by oxidative metabolism and glycolysis. We speculate that a deficit in energy production by oxidative pathways may exist in the affected muscles. Two possible explanations for this would be the partial and/or local reduction of blood supply and the reduction of the muscle oxidative capacity itself. © 2010 Moreno-Torres et al.

Hoekzema E.,Autonomous University of Barcelona | Rojas S.,Institute dAlta Tecnologia | Herance R.,Institute dAlta Tecnologia | Pareto D.,Institute dAlta Tecnologia | And 13 more authors.
Neurobiology of Aging | Year: 2012

The GABA-ergic system, known to regulate neural tissue genesis during cortical development, has been postulated to play a role in cerebral aging processes. Using in vivo molecular imaging and voxel-wise quantification, we aimed to assess the effects of aging on the benzodiazepine (BDZ) recognition site of the GABAA receptor. To visualize BDZ site availability, [11C]-flumazenil microPET acquisitions were conducted in young and old rats. The data were analyzed and region of interest analyses were applied to validate the voxel-wise approach. We observed decreased [11C]-flumazenil binding in the aged rat brains in comparison with the young control group. More specifically, clusters of reduced radioligand uptake were detected in the bilateral hippocampus, cerebellum, midbrain, and bilateral frontal and parieto-occipital cortex. Our results support the pertinence of voxel-wise quantification in the analysis of microPET data. Moreover, these findings indicate that the aging process involves declines in neural BDZ recognition site availability, proposed to reflect alterations in GABAA receptor subunit polypeptide expression. © 2012 Elsevier Inc.

Rojas S.,Center matge Molecular CIM | Gispert J.D.,Institute DAlta Tecnologia | Abad S.,Center matge Molecular CIM | Buaki-Sogo M.,Polytechnic University of Valencia | And 4 more authors.
Molecular Pharmaceutics | Year: 2012

A variety of nanoparticles have been proposed for several biomedical applications. To gauge the therapeutic potential of these nanoparticles, in vivo biodistribution is essential and mandatory. In the present study, ceria nanoparticles (5 nm average particle size) were labeled with 18F to study their in vivo biodistribution in rats by positron emission tomography (PET). The 18F isotope was anchored by reaction of N-succinimidyl 4-[18F]fluorobenzoate (18F-SFB) with a modified nanoparticle surface obtained by silylation with 3-aminopropylsilyl. Radiolabeled ceria nanoparticles accumulated mainly in lungs, spleen, and liver. Metabolic products of the radiolabeled nanoparticulate material were excreted into the urinary tract. © 2012 American Chemical Society.

Guerrero S.,University of Chile | Herance J.R.,Institute dAlta Tecnologia | Rojas S.,Institute dAlta Tecnologia | Mena J.F.,University of Chile | And 8 more authors.
Bioconjugate Chemistry | Year: 2012

Gold nanoparticles (AuNPs) have been extensively used in biological applications because of their biocompatibility, size, and ease of characterization, as well as an extensive knowledge of their surface chemistry. These features make AuNPs readily exploitable for biomedical applications, including drug delivery and novel diagnostic and therapeutic approaches. In a previous work, we studied ex vivo distribution of the conjugate C(AuNP)-LPFFD for its potential uses in the treatment of Alzheimer's disease. In this study, we covalently labeled the conjugate with [ 18F]-fluorobenzoate to study the in vivo distribution of the AuNP by positron emission tomography (PET). After intravenous administration in rat, the highest concentration of the radiolabeled conjugate was found in the bladder and urine with a lower proportion in the intestine, demonstrating progressive accumulation compatible with biliary excretion of the conjugate. The conjugate also accumulated in the liver and spleen. PET imaging allowed us to study the in vivo biodistribution of the AuNPs in a noninvasive and sensitive way using a reduced number of animals. Our results show that AuNPs can be covalently and radioactively labeled for PET biodistribution studies. © 2012 American Chemical Society.

Catafau A.M.,Glaxosmithkline | Searle G.E.,Glaxosmithkline | Bullich S.,Institute dAlta Tecnologia | Gunn R.N.,Glaxosmithkline | And 10 more authors.
Journal of Cerebral Blood Flow and Metabolism | Year: 2010

[11C]NNC112 (8-chloro-7-hydroxy-3-methyl-5-(7-benzofuranyl)-2,3, 4,5-tetrahydro-IH-3-benzazepine), a selective positron-emission tomography (PET) ligand for the D1 receptor (R) over the 5-HT2A R in vitro, has shown lower selectivity in vivo, hampering measurement of D 1 R in the cortex. [11 C]NNC112 PET and intravenous (i.v) ketanserin challenge were used to (1) confirm the previous findings of [ 11 C]NNC112 in vivo D1 R selectivity, and (2) develop a feasible methodology for imaging cortical D1 R without contamination by 5-HT2A R. Seven healthy volunteers underwent [11 C]NNC112 PET scans at baseline and after a 5-HT2A R-blocking dose of ketanserin (0.15 mg/kg, i.v.). Percent BPND change between the post-ketanserin and baseline scans was calculated. Irrespective of the quantification method used, ketanserin pretreatment led to significant decrease of BPND in the cortical (̃30%) and limbic regions (̃20%) but not in the striatum, which contains a much lower amount of 5-HT2A R. Therefore, ketanserin allows D1 R signal to be detected by [ 11 C]NNC112 PET without significant 5-HT2A R contamination. These data confirm the presence of a significant 5-HT 2A R contribution to cortical [11 C]NNC112 signal, and call for caution in the interpretation of published [11 C]NNC112 PET findings on cortical D1 R in humans. In the absence of more selective ligands, [11 C]NNC112 PET with ketanserin can be used for cortical D1 R imaging in vivo. © 2010 ISCBFM.

Martin R.,Polytechnic University of Valencia | Menchon C.,Institute DAlta Tecnologia | Apostolova N.,University of Valencia | Victor V.M.,University of Valencia | And 3 more authors.
ACS Nano | Year: 2010

Diamond nanoparticles (DNPs) obtained by explosive detonation have become commercially available. These commercial DNPs can be treated under Fenton conditions (FeSO4 and H2O2 at acidic pH) to obtain purer DNP samples with a small average particle size (4 nm) and a large population of surface OH groups (HO-DNPs). These Fenton-treated HO-DNPs have been used as a support of gold and platinum nanoparticles (≤2 nm average size). The resulting materials (Au/HO-DNP and Pt/HO-DNP) exhibit a high antioxidant activity against reactive oxygen species induced in a hepatoma cell line. In addition to presenting good biocompatibility, Au/HO- and Pt/HO-DNP exhibit about a two-fold higher antioxidant activity than glutathione, one of the reference antioxidant systems. The most active material against cellular oxidative stress was Au/HO-DNP. © 2010 American Chemical Society.

Romero A.,Autonomous University of Barcelona | Rojas S.,Institute dAlta Tecnologia | Cabanero D.,Autonomous University of Barcelona | Gispert J.D.,Institute dAlta Tecnologia | And 3 more authors.
Anesthesiology | Year: 2011

Background: Neuroplastic changes involved in latent pain sensitization after surgery are poorly defined. We assessed temporal changes in glucose brain metabolism in a postoperative rat model using positron emission tomography. We also investigated brain metabolism after naloxone administration. Methods: Rats were given remifentanil anesthetic and underwent a plantar incision, with 1 mg/kg of (-)-naloxone subcutaneously administered on postoperative days 20 and 21. Using the von Frey test, mechanical thresholds were measured pre-and postoperatively at different time points in awake animals during F-fluorodeoxyglucose (F-FDG) uptake. Brain images were also obtained the day before mechanical testing, using a positron emission tomography R4 scanner (Concorde Microsystems, Siemens, Knoxville, TN). Differences in brain activity were assessed utilizing a statistical parametric mapping. RESULTS:: Surgery induced minor changes in F-FDG uptake in the cerebellum, hippocampus, and posterior cortex, which extended to the thalamus, hypothalamus, and brainstem on days 6 and 7. Changes were still present on day 21. Maximal postoperative hypersensitivity was observed on day 2. The administration of (-)-naloxone on day 21 induced significant hypersensitivity, greatly enhancing the effect on F-FDG uptake. In sham-operated rats, naloxone induced changes limited to the striatum and the cerebellum. Nonnociceptive stimulation with von Frey filaments had no effect on F-FDG uptake. Conclusions: Surgery, remifentanil, and their combination induced long-lasting and significant metabolic changes in the pain brain matrix, with a positive correlation with hypersensitivity after naloxone. Changes in brain F-FDG precipitated by naloxone suggest that surgery under remifentanil anesthetic induces the greatest neuroplastic brain adaptations in opioid-related pathways involved in nociceptive processing and long-lasting pain sensitization. © 2011 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

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