Clinical and molecular diagnosis of non-phosphomannomutase 2 N-linked congenital disorders of glycosylation in Spain.

The congenital disorders of glycosylation (CDG) are defects in glycoprotein and glycolipid glycan synthesis and attachment. They affect multiple organ/systems, but non-specific symptoms render the diagnosis of the different CDG very challenging. Phosphomannomutase 2 (PMM2)-CDG is the most common CDG, but advances in genetic analysis have shown others to occur more commonly than previously thought. The present work reports the clinical and mutational spectrum of 25 non-PMM2 CDG patients. The most common clinical symptoms were hypotonia (80%), motor or psychomotor disability (80%) and craniofacial dysmorphism (76%). Based on their serum transferrin isoform profile, 18 were classified as CDG-I and 7 as CDG-II. Pathogenic variations were found in 16 genes (ALG1, ALG6, ATP6V0A2, B4GALT1, CCDC115, COG7, DOLK, DPAGT1, DPM1, GFPT1, MPI, PGM1, RFT1, SLC35A2, SRD5A3, and SSR4). Overall, 27 variants were identified, 12 of which are novel. The results highlight the importance of combining genetic and biochemical analyses for the early diagnosis of this heterogeneous group of disorders.

A Population-Based Study on Congenital Disorders of Protein N- and Combined with O-Glycosylation Experience in Clinical and Genetic Diagnosis.

OBJECTIVE: To describe the clinical, biochemical, and genetic features of patients with congenital disorders of glycosylation (CDG) identified in Spain during the last 20 years. STUDY DESIGN: Patients were selected among those presenting with multisystem disease of unknown etiology. The isoforms of transferrin and of ApoC3 and dolichols were analyzed in serum; phosphomannomutase and mannosephosphate isomerase activities were measured in fibroblasts. Conventional or massive parallel sequencing (customized panel or Illumina Clinical-Exome Sequencing TruSight One Gene Panel) was used to identify genes and mutations. RESULTS: Ninety-seven patients were diagnosed with 18 different CDG. Eighty-nine patients had a type 1 transferrin profile; 8 patients had a type 2 transferrin profile, with 6 of them showing an alteration in the ApoC3 isoform profile. A total of 75% of the patients had PMM2-CDG presenting with a heterogeneous mutational spectrum. The remaining patients showed mutations in any of the following genes: MPI, PGM1, GFPT1, SRD5A3, DOLK, DPGAT1, ALG1, ALG6, RFT1, SSR4, B4GALT1, DPM1, COG6, COG7, COG8, ATP6V0A2, and CCDC115. CONCLUSION: Based on literature and on this population-based study of CDG, a comprehensive scheme including reported clinical signs of CDG is offered, which will hopefully reduce the timeframe from clinical suspicion to genetic confirmation. The different defects of CDG identified in Spain have contributed to expand the knowledge of CDG worldwide. A predominance of PMM2 deficiency was detected, with 5 novel PMM2 mutations being described.

Preparation, radiolabeling with 99mTc and 67Ga and biodistribution studies of albumin nanoparticles covered with polymers. / Preparación, radiomarcaje con 99mTc y 67Ga y estudios de biodistribución de nanopartículas de albúmina con recubrimientos poliméricos.

OBJECTIVE: To optimize radiolabeling with 99mTc and 67Ga of albumin nanoparticles coated with 4 differents synthetic polymers and to evaluate their stability in vivo and in vitro, as well as their biodistribution in vivo after intravenous administration. MATERIAL AND METHODS: The nanoparticles were prepared using albumin and NOTA-modified albumin by the desolvation method and coated with 4 different polymers; HPMC, GMN2, GPM2 and GTM2. They were purified, lyophilized and characterized. Radiolabelling with 99mTc was perfomed with 74 MBq of 99mTc sodium pertechnetate, previously reduced with and acid solution of tin chloride at different concentrations (0.003, 0.005, 0.007, 0.01, 0.05 and 0.1mg/ml) and at different times (5, 10, 15, 30 and 60minutes) and temperatures (room temperature, 40°C and 60°C). Radiolabelling with 67Ga was perfomed by incubation of the nanoparticles with 37 MBq of 67Gallium chloride (obtained from commercial gallium-67 citrate) at different times (10 and 30minutes) and temperatures (room temperature, 30°C and 60°C), and posterior purification with microconcentrators. The radiochemical purity was evaluated by TLC. Stability studies of radiolabeled nanoparticles in physiological serum and blood plasma were perfomed. Biodistribution studies of nanoparticles coated with GPM2 polymer were carried out in Wistar rats after intravenous administration of the nanoparticles. Control animals were carried out with 99mTc sodium pertechnetate and 67Ga chloride. To do so, the animals were killed and activity in organs was measured in a gamma counter. RESULTS: 99mTc labeling was carried out optimally with a tin concentration of 0.007mg/ ml for the GPM2 nanoparticles and 0.005mg / ml for the rest of the formulations, with a radiolabelling time of 10minutes at room temperature. In the case of 67Ga the label was optimized at 30° C temperature and 30minutes of incubation. In both cases the radiochemical purity obtained was greater than 97%. The nanoparticles showed high stability in vitro after 48hours of labeling (70% nanoparticles labeled with 99mTc and 90% those labeled with 67Ga). Biodistribution studies of nanoparticles 99mTc -GPM2 and 67Ga -NOTA-GPM2 showed a high accumulation of activity in the liver at 2 and 24hours after intravenous administration. CONCLUSION: The labeling procedure with 99mTc and 67Ga of albumin and albumin modified with NOTA nanoparticles allows obtaining nanoparticles with high labeling yields and adequate in vitro stability, allowing their use for in vivo studies.

[Children with ADHD: a retrospective description of their behavioural features as toddlers]. / Estilo comportamental al inicio del segundo año de vida: estudio retrospectivo en escolares afectados de trastorno por déficit de atención e hiperactividad.

OBJECTIVES: To study the relationship between behavioural profile of children suffering from Attention Deficit Hyperactivity Disorder (ADHD) and the previous behavioural style of these patients as toddlers. SUBJECTS AND METHODS: We asked the parents of 50 schoolchildren with ADHD, and those of 30 controls, to fill in a Spanish version of the Toddler Behaviour Questionnaire (TBQ) from their retrospective perception of their children's behaviour as toddlers. TBQ items were grouped by factor analysis; t-Student between the scores of both groups and a multiple correlation analysis of TBQ and DSM-IV-ADHD-RS in each of the groups were used. RESULTS: Children in the ADHD group were reported by parents to have had a different toddler behavioural profile in comparison to that of control children (P<0.05). These differences were associated with adapting to new environments, mood, regularity and stability of play behaviour. A correlation was found between behavioural profile in DSM-IV-ADHD- RS and TBQ. CONCLUSIONS: The results of this study should be interpreted with caution. However, they suggest that in the fifth trimester of life a particular behavioural style as regards regularity, stability of play, and mood, could indicate a risk of developing ADHD in the future. This behavioural style should be taken into consideration in rearing and early education prospective studies.

[Use of 11C-(+)-alpha -dihydrotetrabenazine for the assessment of dopaminergic innervation in animal models of Parkinson's disease]. / Utilización de la 11C-(+)-alpha -dihidrotetrabenazina para la evaluación de la inervación dopaminérgica en modelos animales de la enfermedad de Parkinson.

AIM: This study evaluates the utility of (11)C-(+)-alpha -dihydrotetrabenazine ((11)C-(+)DTBZ) in the quantification of dopaminergic innervation by positron emission tomography (PET) in rat and monkey, two animal species used as animal models of Parkinson's disease. MATERIAL AND METHODS: Healthy control animals (n = 10) and the effect of 6-hydroxidopamine (6-OHDA) neurotoxic were studied in rats. (18)F-DOPA PET studies and digital quantitative autoradiography were also carried out. Studies with Macaca fascicularis were performed in control and 1-methyl 4-phenyl 1, 2, 3, 6-tetrahydropyridine (MPTP) treated animals. RESULTS: In both species high quality images were generated in which clear uptake of (11)C-(+)DTBZ was found in the striatum. (11)C-(+)DTBZ uptake quantification was estimated by creating parametric images and binding potential (BP) calculation. BP in control rats was 1.10 +/- 0.16 (mean +/- standard deviation [SD], whereas 6-OHDA produced a decrease in the uptake depending on the lesion degree. Images obtained with (18)F-DOPA were not adequate for the analysis as they did not discriminate the stratum whereas digital quantitative autoradiography studies confirmed the high affinity of striatum by (11)C-(+)DTBZ. In monkeys, final BP values were 1.31 and 1.06 and MPTP treatment reduced uptake by 40 %. CONCLUSIONS: The quality of PET images and the decrease of uptake in 6-OHDA and MPTP lesions show that (11)C-(+)DTBZ is an adequate radiotracer for the study of dopaminergic innervation in these animal models.

[Quick and simple synthesis of (11)C-(+)-alpha-dihydrotetrabenazine to be used as a PET radioligand of vesicular monoamine transporters]. / Síntesis rápida y simplificada de C-(+)-alpha-dihidrotetrabenazina para su utilización como radioligando PET de los transportadores vesiculares de monoaminas.

UNLABELLED: Dihydrotetrabenazine (2-hydroxy-3-isobutyl-9,10-dimethoxy-1,3,4,6,7-hexahydro-11bH-benzo[a]-quinolizine, DTBZ) has become the ideal radioligand for the presynaptic vesicular monoamine transporter VMAT2 based on its high binding affinity and optimal lipophilicity. OBJECTIVE: To develop an automatic procedure for labelling DTBZ with carbon-11, which has been shown to be a highly effective marker for in vivo studies of neuronal losses in animal models with Parkinson's disease using positron emission tomography (PET). MATERIALS AND METHODS: We have developed a new fully automated synthesis procedure to obtain 11C-(+)DTBZ quickly and simply through labelling the precursor -(+)desmethyldihy-drotetrabenazine- at room temperature in the presence of dimethyl sulfoxide (DMSO) and potassium hydroxide (KOH), using 11CH3I as primary precursor. The final purification was carried out by solid phase extraction using commercially available cartridges and the residual solvents (DMSO and ethyl ether) were eliminated by evaporation. RESULTS: The whole procedure was automated, and after 54 syntheses, an average production of 1.94 GBq of sterile, pyrogen-free 11C-(+)DTBZ with a radiochemical purity > 99 % was obtained with 5 minutes irradiation and 6 minutes of synthesis after 11CH3I production. 11C-(+)DTBZ binding to presynaptic dopamine nerve terminals has been demonstrated by MicroPET studies in Wistar rats and M. Fascicularis monkeys. CONCLUSIONS: This new synthesis procedure is quick and simple, due to optimised techniques, which have allowed elimination of residual solvents based on their polarity for the final purification. It is also applicable to other automatic syntheses for obtaining compounds labelled by methylation reactions.

18F-FDG metabolism in a rat model of chronic infarction: a 17-sector semiquantitative analysis.

UNLABELLED: Strategies to establish the functional benefit of cell therapy in cardiac regeneration and the potential mechanism are needed. AIMS: Development of a semi-quantitative method for non invasive assessment of cardiac viability and function in a rat model of myocardial infarction (MI) based on the use of microPET. ANIMALS, METHODS: Ten rats were subjected to myocardial imaging 2, 7, 14, 30, 60 and 90 days after left coronary artery ligation. Intravenous 18F-fluoro-2-deoxy-2-D-glucose (18F-FDG) was administered and regional 18F activity concentrations per unit area were measured in 17 regions of interest (ROIs) drawn on cardiac polar maps. By comparing the differences in 18F uptake between baseline and each of the follow up time points, parametric polar maps of statistical significance (PPMSS) were calculated. Left ventricular ejection fraction (LVEF) was blindly assessed echocardiographically. All animals were sacrificed for histopathological analysis after 90 days. RESULTS: The diagnostic quality of 18F-FDG microPET images was excellent. PPMSS demonstrated a statistically significant decrease in 18F concentrations as early as 48 hours after MI in 4 of the 17 ROIs (segments 7, 13, 16 and 17; p < 0.05) that persisted throughout the study. Semiquantitative analysis of 18F-FDG uptake correlated with echocardiographic decrease in LVEF (p < 0.001). CONCLUSION: The use of PPMSS based on 18F-FDG-microPET provides valuable semi-quantitative information of heart glucose metabolism allowing for non-invasive follow up thus representing a useful strategy for assessment of novel therapies in cardiac regeneration.

Radiation dosimetry and biodistribution in non-human primates of the sodium/iodide PET ligand [(18)F]-tetrafluoroborate.

BACKGROUND: [(18)F]-tetrafluoroborate is a PET radiotracer taken up by the sodium/iodide symporter (NIS). Albeit the in vivo behavior in rodents is similar to the (99m)Tc-pertechnetate, no studies exist in primates or in humans. The aims of this study were to evaluate the biodistribution of [(18)F]-tetrafluoroborate in non-human primates with PET and to estimate the absorbed dose in organs. METHODS: Whole-body PET imaging was done in a Siemens ECAT HR+ scanner in two male Macaca fascicularis monkeys. After an i.v. injection of 24.93 ± 0.05 MBq/kg of [(18)F]-tetrafluoroborate, prepared by isotopic exchange of sodium tetrafluoroborate with [(18)F]-fluoride under acidic conditions, eight sequential images from the head to the thigh (five beds) were collected for a total duration of 132 min. The whole-body emission scan was reconstructed applying attenuation and scatter corrections. After image reconstruction, three-dimensional volumes of interest (VOIs) were hand-drawn on the PET transaxial or coronal slices of the frame where the organ was most conspicuous. Time-activity curves for each VOI were obtained, and the organ residence times were calculated by integration of the time-activity curves. Human absorbed doses were estimated using the OLINDA/EXM software and the standard human model. RESULTS: [(18)F]-tetrafluoroborate was able to discriminate clearly the thyroid gland with an excellent signal-to-noise ratio. Most of the radiotracers (residence time) are localised in the organs that express NIS (stomach wall, salivary glands, thyroid, olfactory mucosa), are involved in excretion (kidneys and bladder), or reflect the vascular phase (heart and lungs). Considering the OLINDA source organs, the critical organs were the stomach wall, thyroid and bladder wall, with absorbed doses lower than 0.078 mGy/MBq. The effective dose was 0.025 mSv/MBq. CONCLUSIONS: [(18)F]-tetrafluoroborate is a very useful radiotracer for PET thyroid imaging in primates, with a characteristic biodistribution in organs expressing NIS. It delivers an effective dose slightly higher than the dose produced by (99m)Tc-pertechnetate but much lower than that produced by radioiodine in the form of (131)INa, (123)INa, or (124)INa.

The molecular landscape of phosphomannose mutase deficiency in iberian peninsula: identification of 15 population-specific mutations.

PMM2-CDG is an autosomal recessive disorder and the most frequent form of congenital disorder of N-glycosylation, with more than 100 mutations identified to date. Sixty-six patients from 58 unrelated families were diagnosed as PMM2-CDG (CDG-Ia) based on clinical signs or because of a previous affected sibling. They all presented a type 1 serum transferrin isoform pattern, and, in most cases, the disease was confirmed by determining PMM2 activity in fibroblasts and/or lymphocytes. Residual PMM2 activity in fibroblasts ranged from not detectable to 60% of the mean controls. DNA and RNA were isolated from fresh blood or fibroblasts from patients to perform molecular studies of the PMM2 gene, resulting in the identification of 30 different mutations, four of them newly reported here (p.Y102C, p.T118S, p.P184T, and p.D209G). From these 30 mutations, 15 have only been identified among Iberian PMM2-CDG patients. As in other Caucasian populations, p.R141H was the most frequent mutation (24 alleles, prevalence 20.6%), but less than in other European series in which this mutation represents 35-43% of the disease alleles. The next frequent mutations were p.D65Y (12 alleles, prevalence 10.3%) and p.T237M (9 alleles, prevalence 7.6%), while p.F119L and p.E139K, the most frequent changes in Scandinavian and French populations, respectively, were not found in our patients. The most common genotype was [p.R141H] + [p.T237M], and four homozygous patients for p.Y64C, p.D65Y, p.P113L, and p.T237M were detected. The broad mutational spectrum and the diversity of phenotypes found in the Iberian populations hamper genotype-phenotype correlation.

Preparación, radiomarcaje con 99mTc y 67Ga y estudios de biodistribución de nanopartículas de albúmina con recubrimientos poliméricos / Preparation, radiolabeling with 99mTc and 67Ga and biodistribution studies of albumin nanoparticles covered with polymers

OBJETIVO: Optimizar el radiomarcaje con 99mTc y 67Ga de nanopartículas de albúmina recubiertas con 4 polímeros sintéticos distintos y evaluar su estabilidad in vivo e in vitro, así como su biodistribución in vivo tras su administración intravenosa. MATERIAL Y MÉTODOS: Las nanopartículas se prepararon empleando albúmina y albúmina modificada con NOTA mediante el método de desolvatación y se recubrieron con 4 polímeros distintos; HPMC, GMN2, GPM2 y GTM2. Se purificaron, liofilizaron y caracterizaron. El marcaje con 99mTc se realizó con 74MBq de pertecnetato [99mTc] sódico previamente reducido con una disolución ácida de cloruro de estaño a diferentes concentraciones (0,003; 0,005; 0,007; 0,01; 0,05 y 0,1mg/ml), a distintos tiempos (5, 10, 15, 30 y 60min) y temperaturas (temperatura ambiente, 40°C y 60°C). El marcaje con 67Ga se llevó a cabo mediante incubación de las nanopartículas con 37MBq de cloruro de 67Ga (obtenido a partir de citrato de 67Ga comercial) a distintos tiempos (10 y 30min) y temperaturas (temperatura ambiente, 30°C y 60°C) y posterior purificación con microconcentradores. La pureza radioquímica de ambos marcajes se evaluó mediante TLC. Se llevaron a cabo estudios de estabilidad de las nanopartículas marcadas en suero fisiológico y plasma sanguíneo. Los estudios de biodistribución de las nanopartículas recubiertas con el polímero GPM2 se llevaron a cabo en ratas Wistar tras la administración intravenosa de las nanopartículas. Se realizaron animales control con pertecnetato [99mTc] sódico y cloruro de 67Ga. Posteriormente, los animales fueron sacrificados y se midió la actividad de los órganos en un contador gamma. RESULTADOS: El marcaje con 99mTc se llevó a cabo de forma óptima con una concentración de estaño de 0,007mg/ml para las nanopartículas GPM2 y de 0,005mg/ml para el resto de formulaciones, con un tiempo de marcaje de 10min y a temperatura ambiente. En el caso del 67Ga el marcaje se optimizó a 30°C de temperatura y 30min de incubación. En ambos casos, la pureza radioquímica obtenida fue superior al 97%. Las nanopartículas presentaron una elevada estabilidad in vitro pasadas las 48h del marcaje (70% las nanopartículas marcadas con 99mTc y 90% las marcadas con 67Ga). Los estudios de biodistribución de las nanopartículas [99mTc]-GPM2 y [67Ga]-NOTA-GPM2 mostraron una elevada acumulación de actividad en el hígado tanto a las 2h como a las 24h de la administración intravenosa. CONCLUSIÓN: El procedimiento de marcaje con 99mTc y 67Ga de nanopartículas de albúmina y albúmina modificada con NOTA permite la obtención de nanopartículas con elevados rendimientos de marcaje y una adecuada estabilidad in vitro, permitiendo su utilización para la realización de estudios in vivo

OBJECTIVE: To optimize radiolabeling with 99mTc and 67Ga of albumin nanoparticles coated with 4 differents synthetic polymers and to evaluate their stability in vivo and in vitro, as well as their biodistribution in vivo after intravenous administration. MATERIAL AND METHODS: The nanoparticles were prepared using albumin and NOTA-modified albumin by the desolvation method and coated with 4 different polymers; HPMC, GMN2, GPM2 and GTM2. They were purified, lyophilized and characterized. Radiolabelling with 99mTc was perfomed with 74 MBq of 99mTc sodium pertechnetate, previously reduced with and acid solution of tin chloride at different concentrations (0.003, 0.005, 0.007, 0.01, 0.05 and 0.1mg/ml) and at different times (5, 10, 15, 30 and 60minutes) and temperatures (room temperature, 40°C and 60°C). Radiolabelling with 67Ga was perfomed by incubation of the nanoparticles with 37 MBq of 67Gallium chloride (obtained from commercial gallium-67 citrate) at different times (10 and 30minutes) and temperatures (room temperature, 30°C and 60°C), and posterior purification with microconcentrators. The radiochemical purity was evaluated by TLC. Stability studies of radiolabeled nanoparticles in physiological serum and blood plasma were perfomed. Biodistribution studies of nanoparticles coated with GPM2 polymer were carried out in Wistar rats after intravenous administration of the nanoparticles. Control animals were carried out with 99mTc sodium pertechnetate and 67Ga chloride. To do so, the animals were killed and activity in organs was measured in a gamma counter. RESULTS: 99mTc labeling was carried out optimally with a tin concentration of 0.007mg/ ml for the GPM2 nanoparticles and 0.005mg / ml for the rest of the formulations, with a radiolabelling time of 10minutes at room temperature. In the case of 67Ga the label was optimized at 30° C temperature and 30minutes of incubation. In both cases the radiochemical purity obtained was greater than 97%. The nanoparticles showed high stability in vitro after 48hours of labeling (70% nanoparticles labeled with 99mTc and 90% those labeled with 67Ga). Biodistribution studies of nanoparticles 99mTc -GPM2 and 67Ga -NOTA-GPM2 showed a high accumulation of activity in the liver at 2 and 24hours after intravenous administration. CONCLUSION: The labeling procedure with 99mTc and 67Ga of albumin and albumin modified with NOTA nanoparticles allows obtaining nanoparticles with high labeling yields and adequate in vitro stability, allowing their use for in vivo studies

Estilo comportamental al inicio del segundo año de vida: estudio retrospectivo en escolares afectados de trastorno por déficit de atención e hiperactividad / Children with ADHD: A retrospective description of their behavioural features as toddlers

Objetivos: Estudiar la posible relación entre el perfil comportamental de escolares afectos de trastorno por déficit de atención e hiperactividad (TDAH) y el estilo de conducta que poseían al inicio del segundo año de vida. Sujetos y métodos: Los padres de 50 niños afectados de TDAH y los padres de 30 niños controles contestaron una versión española del TBQ (Toddler Behaviour Questionnaire) acerca de sus percepciones retrospectivas de la conducta de sus hijos al inicio del segundo año de vida. Los ítems del TBQ se agruparon mediante un análisis factorial. Se estudiaron las diferencias (t-Student) de las puntuaciones del TBQ entre ambos grupos y se aplicó un análisis de correlación múltiple entre las puntuaciones en el TBQ y en la escala del Manual Diagnóstico y Estadístico de los Trastornos Mentales IV del TDAH. Resultados: Según la percepción de sus padres, los niños afectos de TDAH (como grupo) habían mostrado al inicio del segundo año un estilo de conducta diferente al de los niños del grupo control (p<0,05); estas diferencias se daban en las siguientes dimensiones de la conducta: regularidad, humor y estabilidad durante el juego. Conclusiones: Aunque los resultados del presente estudio deben considerarse con precaución, parecen mostrar que desde el quinto trimestre de vida es diferenciable un particular estilo de conducta en lo tocante a regularidad, humor y estabilidad durante el juego, que puede indicar riesgo de TDAH en edades posteriores. Este estilo de conducta debe tenerse en cuenta en la educación temprana y ser objeto de estudios prospectivos (AU)

Objectives: To study the relationship between behavioural profile of children suffering from Attention Deficit Hyperactivity Disorder (ADHD) and the previous behavioural style of these patients as toddlers. Subjects and methods: We asked the parents of 50 schoolchildren with ADHD, and those of 30 controls, to fill in a Spanish version of the Toddler Behaviour Questionnaire (TBQ) from their retrospective perception of their children's behaviour as toddlers. TBQ items were grouped by factor analysis; t-Student between the scores of both groups and a multiple correlation analysis of TBQ and DSM-IV-ADHD-RS in each of the groups were used. Results: Children in the ADHD group were reported by parents to have had a different toddler behavioural profile in comparison to that of control children (P<0.05). These differences were associated with adapting to new environments, mood, regularity and stability of play behaviour. A correlation was found between behavioural profile in DSM-IV-ADHD- RS and TBQ. Conclusions: The results of this study should be interpreted with caution. However, they suggest that in the fifth trimester of life a particular behavioural style as regards regularity, stability of play, and mood, could indicate a risk of developing ADHD in the future. This behavioural style should be taken into consideration in rearing and early education prospective studies (AU)

Síntesis rápida y simplificada de 11C-(+)-alfa -dihidrotetrabenazina para su utilización como radioligando PET de los transportadores vesiculares de monoaminas / Quick and simple synthesis of 11C-(+)-alpha-dihydrotetrabenazine to be used as a PET radioligand of vesicular monoamine transporters

La dihidrotetrabenazina (2-hidroxi-3-isobutil-9,10-dimetoxi-1,3,4,6,7-hexahidro-11bH-benzo[a]-quinolizina, DTBZ) se ha convertido en el ligando ideal de los transportadores presinápticos de monoaminas (VMAT2) debido a su elevada afinidad de unión y su lipofilicidad. Objetivo. Desarrollar un procedimiento de síntesis automático para el marcaje con carbono-11 de la DTBZ para utilizarla como marcador en el estudio in vivo mediante tomografía por emisión de positrones de pérdidas neuronales en modelos animales de enfermedad de Parkinson. Material y métodos. Se ha diseñado un nuevo método de síntesis totalmente automatizado para la obtención de 11C-(+)DTBZ. La reacción de metilación del precursor ­(+)desmetildihidrotetrabenazina­ se lleva a cabo a temperatura ambiente, a partir de la obtención de 11CH3I que utilizamos como precursor primario, en presencia de dimetilsulfóxido e hidróxido de potasio. Para los procesos de purificación se han utilizado cartuchos de extracción en fase sólida alúmina y los disolventes residuales del producto final se eliminaron mediante evaporación bajo flujo de helio. Resultados. De las 54 síntesis realizadas se han obtenido, con un tiempo de bombardeo de 5 minutos, y 6 minutos de síntesis tras la obtención de 11CH3I, unas producciones medias de 1,94 ± 0,13 GBq de 11C-(+)DTBZ, estéril, apirógeno y con una pureza radioquímica > 99 %. Conclusiones. Este nuevo procedimiento de síntesis es rápido y simple, ya que para la purificación final se han optimizado técnicas que permitieran la eliminación de los disolventes residuales basándonos en su polaridad y es aplicable a otras síntesis automáticas para la obtención de otros compuestos marcados mediante reacciones de metilación

Dihydrotetrabenazine (2-hydroxy-3-isobutyl-9,10-dimethoxy-1,3,4,6,7-hexahydro-11bH-benzo[a]-quinolizine, DTBZ) has become the ideal radioligand for the presynaptic vesicular monoamine transporter VMAT2 based on its high binding affinity and optimal lipophilicity. Objective. To develop an automatic procedure for labelling DTBZ with carbon-11, which has been shown to be a highly effective marker for in vivo studies of neuronal losses in animal models with Parkinson's disease using positron emission tomography (PET). Materials and methods. We have developed a new fully automated synthesis procedure to obtain 11C-(+)DTBZ quickly and simply through labelling the precursor ­(+)desmethyldihydrotetrabenazine­ at room temperature in the presence of dimethyl sulfoxide (DMSO) and potassium hydroxide (KOH), using 11CH3I as primary precursor. The final purification was carried out by solid phase extraction using commercially available cartridges and the residual solvents (DMSO and ethyl ether) were eliminated by evaporation. Results. The whole procedure was automated, and after 54 syntheses, an average production of 1.94 GBq of sterile, pyrogen-free 11C-(+)DTBZ with a radiochemical purity > 99 % was obtained with 5 minutes irradiation and 6 minutes of synthesis after 11CH3I production. 11C-(+)DTBZ binding to presynaptic dopamine nerve terminals has been demonstrated by MicroPET studies in Wistar rats and M. Fascicularis monkeys. Conclusions. This new synthesis procedure is quick and simple, due to optimised techniques, which have allowed elimination of residual solvents based on their polarity for the final purification. It is also applicable to other automatic syntheses for obtaining compounds labelled by methylation reactions

Utilización de la 11C-(+)-α -dihidrotetrabenazina para la evaluación de la inervación dopaminérgica en modelos animales de la enfermedad de Parkinson / Use of 11C-(+)-α -dihydrotetrabenazine for the assessment of dopaminergic innervation in animal models of Parkinson’s disease

Objetivo. Este trabajo evalúa la idoneidad del radiotrazador 11C-(+)-α -dihidrotetrabenazina (11C-(+)DTBZ) para cuantificar mediante tomografía de emisión de positrones (PET) la inervación dopaminérgica en rata y mono, especies utilizadas como modelos animales en el estudio de la enfermedad de Parkinson. Material y métodos. En ratas se estudió una población control sana (n = 10) y el efecto del neurotóxico 6-hidroxidopamina (6-OHDA), además de realizarse estudios PET con 6-[(18)F]-fluoro-L-DOPA (18F-DOPA) y de autorradiografía digital cuantitativa. El estudio en Macaca fascicularis se realizó en animales control y tratados con el tóxico 1-metil-4-fenil-1,2,3,6-tetrahidropiridina (MPTP). Resultados. En ambas especies se obtuvieron imágenes de gran calidad donde se observó una alta captación de 11C-(+) DTBZ en el estriado. La cuantificación se realizó mediante la creación de imágenes paramétricas y el cálculo del potencial de unión (BP). La medida del BP en la población control de ratas arrojó un valor de 1,10 ± 0,16 (media ± error estándar [EE]), mientras que los estriados dañados con 6-OHDA mostraron una captación disminuida en función del grado de la lesión. Las imágenes obtenidas con 18F-DOPA no fueron aptas para el análisis al no discriminar los estriados, mientras que el estudio mediante autorradiografía digital cuantitativa confirmó la elevada afinidad de la 11C-(+)DTBZ por estas estructuras. En monos, el valor final de BP fue de 1,31 y 1,06 mientras que el tratamiento con MPTP disminuyó la captación en un 40 %. Conclusiones. La calidad de las imágenes PET y la disminución de la captación en las lesiones con 6-OHDA y MPTP indican que la 11C-(+)DTBZ es un radiotrazador adecuado para el estudio de la inervación dopaminérgica en estas especies animales

Aim. This study evaluates the utility of 11C-(+)-α -dihydrotetrabenazine (11C-(+)DTBZ) in the quantification of dopaminergic innervation by positron emission tomography (PET) in rat and monkey, two animal species used as animal models of Parkinson's disease. Material and methods. Healthy control animals (n = 10) and the effect of 6-hydroxidopamine (6-OHDA) neurotoxic were studied in rats. 18F-DOPA PET studies and digital quantitative autoradiography were also carried out. Studies with Macaca fascicularis were performed in control and 1-methyl 4-phenyl 1, 2, 3, 6-tetrahydropyridine (MPTP) treated animals. Results. In both species high quality images were generated in which clear uptake of 11C-(+)DTBZ was found in the striatum. 11C-(+)DTBZ uptake quantification was estimated by creating parametric images and binding potential (BP) calculation. BP in control rats was 1.10 ± 0.16 (mean ± standard deviation [SD], whereas 6-OHDA produced a decrease in the uptake depending on the lesion degree. Images obtained with 18F-DOPA were not adequate for the analysis as they did not discriminate the stratum whereas digital quantitative autoradiography studies confirmed the high affinity of striatum by 11C-(+)DTBZ. In monkeys, final BP values were 1.31 and 1.06 and MPTP treatment reduced uptake by 40 %. Conclusions. The quality of PET images and the decrease of uptake in 6-OHDA and MPTP lesions show that 11C-(+)DTBZ is an adequate radiotracer for the study of dopaminergic innervation in these animal models