Technical Aspects of Coenzyme Q₁₀ Analysis:Validation of a New HPLC-ED Method

The biochemical measurement of the CoQ status in different tissues can be performed using HPLC with electrochemical detection (ED). Because the production of the electrochemical cells used with the Coulochem series detectors was discontinued, we aimed to standardize a new HPLC-ED method with new equipment. We report all technical aspects, troubleshooting and its performance in different biological samples, including plasma, skeletal muscle homogenates, urine and cultured skin fibroblasts. Analytical variables (intra- and inter-assay precision, linearity, analytical measurement range, limit of quantification, limit of detection and accuracy) were validated in calibrators and plasma samples and displayed adequate results. The comparison of the results of a new ERNDIM external quality control (EQC) scheme for the plasma CoQ determination between HPLC-ED (Lab 1) and LC-MS/MS (Lab 2) methods shows that the results of the latter were slightly higher in most cases, although a good consistency was generally observed. In conclusion, the new method reported here showed a good analytical performance. The global quality of the EQC scheme results among different participants can be improved with the contribution of more laboratories

Physiopathological bases of the disease caused by HACE1 mutations: alterations in autophagy, mitophagy and oxidative stress response

Recessive HACE1 mutations are associated with a severe neurodevelopmental disorder (OMIM: 616756). However, the physiopathologycal bases of the disease are yet to be completely clarified. Whole-exome sequencing identified homozygous HACE1 mutations (c.240C>A, p.Cys80Ter) in a patient with brain atrophy, psychomotor retardation and 3-methylglutaconic aciduria, a biomarker of mitochondrial dysfunction. To elucidate the pathomechanisms underlying HACE1 deficiency, a comprehensive molecular analysis was performed in patient fibroblasts. Western Blot demonstrated the deleterious effect of the mutation, as the complete absence of HACE1 protein was observed. Immunofluorescence studies showed an increased number of LC3 puncta together with the normal initiation of the autophagic cascade, indicating a reduction in the autophagic flux. Oxidative stress response was also impaired in HACE1 fibroblasts, as shown by the reduced NQO1 and Hmox1 mRNA levels observed in H2O2-treated cells. High levels of lipid peroxidation, consistent with accumulated oxidative damage, were also detected. Although the patient phenotype could resemble a mitochondrial defect, the analysis of the mitochondrial function showed no major abnormalities. However, an important increase in mitochondrial oxidative stress markers and a strong reduction in the mitophagic flux were observed, suggesting that the recycling of damaged mitochondria might be targeted in HACE1 cells. In summary, we demonstrate for the first time that the impairment of autophagy, mitophagy and oxidative damage response might be involved in the pathogenesis of HACE1 deficiency

Apo AIV and citrulline plasma concentrations in Short Bowel Syndrome patients: the influence of Short Bowel Anatomy

Introduction Parenteral nutrition (PN) dependence in short bowel syndrome (SBS) patients is linked to the functionality of the remnant small bowel (RSB). Patients may wean off PN following a period of intestinal adaptation that restores this functionality. Currently, plasma citrulline is the standard biomarker for monitoring intestinal functionality and adaptation. However, available studies reveal that the relationship the biomarker with the length and function of the RSB is arguable. Thus, having additional biomarkers would improve pointing out PN weaning. Aim By measuring concomitant changes in citrulline and the novel biomarker apolipoprotein AIV (Apo AIV), as well as taking into account the anatomy of the RSB, this exploratory study aims to a better understanding of the intestinal adaptation process and characterization of the SBS patients under PN. Methods Thirty four adult SBS patients were selected and assigned to adapted (aSBS) and non-adapted (nSBS) groups after reconstructive surgeries. Remaining jejunum and ileum lengths were recorded. The aSBS patients were either on an oral diet (ORAL group), those with intestinal insufficiency, or on oral and home parenteral nutrition (HPN group), those with chronic intestinal failure. Apo AIV and citrulline were analyzed in plasma samples after overnight fasting. An exploratory ROC analysis using citrulline as gold standard was performed. Results Biomarkers, Apo AIV and citrulline showed a significant correlation with RSBL in aSBS patients. In jejuno-ileocolic patients, only Apo AIV correlated with RSBL (rb = 0.54) and with ileum length (rb = 0.84). In patients without ileum neither biomarker showed any correlation with RSBL. ROC analysis indicated the Apo AIV cut-off value to be 4.6 mg /100 mL for differentiating between the aSBS HPN and ORAL groups. Conclusions Therefore, in addition to citrulline, Apo AIV can be set as a biomarker to monitor intestinal adaptation in SBS patients. As short bowel anatomy is shown to influence citrulline and Apo AIV plasma values, both biomarkers complement each other furnishing a new insight to manage PN dependence

Inter-rater reliability assessment for the new-born screening quality assurance

IntroductionTo ensure the quality of the new-born screening (NBS), our laboratory reviewed the analytical procedure to detect subjective steps that may represent a risk to the patient. Two subjective activities were identified in the extra-analytical phases: the classification of dried blood spots (DBS) according to their quality and the assignment of haemoglobin patterns. To keep these activities under control, inter-rater studies were implemented. This study aimed to evaluate the inter-rater reliability and the effectiveness of the measures taken to improve the agreement between observers, to assure NBS results’ quality. Materials and methodsDried blood spots specimens were used for the inter-rater studies. Ten studies were performed to assess DBS quality classification, and four to assess the assignment of haemoglobin patterns. Krippendorff’s alpha test was used to estimate inter-rater reliability. Causes were investigated when alpha values were below 0.80. ResultsFor both activities, the reliability obtained in the first studies was inadequate. After investigation, we detected that the criterion to classify a DBS as scant was not consolidated, and also a lack of consensus on whether or not to report Bart’s haemoglobin depending on its percentage. Alpha estimates became higher once the training was reinforced and a consensus about the appropriate criteria to be applied was reached. ConclusionInter-rater reliability assessment helped us to ensure the quality of subjective activities that could add variability to NBS results. Furthermore, the evolution of the alpha value over time allowed us to verify the effectiveness of the measures adopted

Cistinosis en pacientes adolescentes y adultos: Recomendaciones para la atención integral de la cistinosis

ResumenIntroducciónLa cistinosis es una enfermedad lisosomal minoritaria de expresión sistémica con especial afectación renal y oftalmológica, en la que los pacientes inician terapia renal sustitutiva en la primera década de la vida en ausencia de tratamiento. El pronóstico de la cistinosis depende del diagnóstico precoz, la pronta instauración del tratamiento con cisteamina y el buen cumplimiento terapéutico. La progresión de la enfermedad renal y de las complicaciones extrarrenales y una menor supervivencia, son más acentuadas en pacientes no adherentes.ObjetivoEl objetivo de este trabajo fue la elaboración de unas recomendaciones para la atención integral de la cistinosis y la transición del adolescente a la medicina del adulto, basadas en la experiencia clínica, con el fin de reducir el impacto de la enfermedad y mejorar la calidad de vida y el pronóstico del paciente.MétodoBúsqueda bibliográfica y reuniones de consenso de un equipo multidisciplinar de expertos en la práctica clínica con pacientes afectos de cistinosis (Grupo T-CiS.bcn), procedentes de 5 hospitales localizados en Barcelona.ResultadosEl documento recoge recomendaciones específicas y necesarias para el diagnóstico, tratamiento y seguimiento multidisciplinar de la cistinosis en las siguientes áreas: nefrología, diálisis, trasplante renal, oftalmología, endocrinología, neurología, laboratorio, consejo genético, enfermería y farmacia.ConclusionesDisponer de un documento de referencia para la atención integral de la cistinosis constituye una herramienta de soporte para los profesionales de la salud que asisten a estos pacientes. Los principales pilares en los que se sustenta son: a) el enfoque multidisciplinar, b) la adecuada monitorización de la enfermedad y control de los niveles de cistina intraleucocitarios, c) la importancia de la adherencia al tratamiento con cisteamina y d) la promoción del autocuidado del paciente mediante programas de educación en la enfermedad. Todo ello conducirá, en una segunda fase, a la elaboración de un modelo de transición coordinado entre los servicios de pediatría y de adultos que contemple las necesidades específicas de la cistinosis.AbstractIntroductionCystinosis is a rare lysosomal systemic disease that mainly affects the kidney and the eye. Patients with cystinosis begin renal replacement therapy during the first decade of life in absence of treatment. Prognosis of cystinosis depends on early diagnosis, and prompt starting and good compliance with cysteamine treatment. Kidney disease progression, extra-renal complications and shorter life expectancy are more pronounced in those patients that do not follow treatment.The objective of this work was to elaborate recommendations for the comprehensive care of cystinosis and the facilitation of patient transition from paediatric to adult treatment, based on clinical experience. The goal is to reduce the impact of the disease, and to improve patient quality of life and prognosis.MethodsBibliographic research and consensus meetings among a multidisciplinary professional team of experts in the clinical practice, with cystinotic patients (T-CiS.bcn group) from 5 hospitals located in Barcelona.ResultsThis document gathers specific recommendations for diagnosis, treatment and multidisciplinary follow-up of cystinotic patients in the following areas: nephrology, dialysis, renal transplant, ophthalmology, endocrinology, neurology, laboratory, genetic counselling, nursing and pharmacy.ConclusionsA reference document for the comprehensive care of cystinosis represents a support tool for health professionals who take care of these patients. It is based on the following main pillars: a) a multi-disciplinary approach, b) appropriate disease monitoring and control of intracellular cystine levels in leukocytes, c) the importance of adherence to treatment with cysteamine, and d) the promotion of patient self-care by means of disease education programmes. All these recommendations will lead us, in a second phase, to create a coordinated transition model between paediatric and adult care services which will cover the specific needs of cystinosis

Ghrelin causes a decline in GABA release by reducing fatty acid oxidation in cortex

Lipid metabolism, specifically fatty acid oxidation (FAO) mediated by carnitine palmitoyltransferase (CPT) 1A, has been described to be an important actor of ghrelin action in hypothalamus. However, it is not known whether CPT1A and FAO mediate the effect of ghrelin on the cortex. Here, we show that ghrelin produces a differential effect on CPT1 activity and γ-aminobutyric acid (GABA) metabolism in the hypothalamus and cortex of mice. In the hypothalamus, ghrelin enhances CPT1A activity while GABA transaminase (GABAT) activity, a key enzyme in GABA shunt metabolism, is unaltered. However, in cortex CPT1A activity and GABAT activity are reduced after ghrelin treatment. Furthermore, in primary cortical neurons, ghrelin reduces GABA release through a CPT1A reduction. By using CPT1A floxed mice, we have observed that genetic ablation of CPT1A recapitulates the effect of ghrelin on GABA release in cortical neurons, inducing reductions in mitochondrial oxygen consumption, cell content of citrate and α-ketoglutarate, and GABA shunt enzyme activity. Taken together, these observations indicate that ghrelin-induced changes in CPT1A activity modulate mitochondrial function, yielding changes in GABA metabolism. This evidence suggests that the action of ghrelin on GABA release is region specific within the brain, providing a basis for differential effects of ghrelin in the central nervous system. Keywords: Ghrelin, GABA, Fatty acid oxidation, CPT1A, Cortical neuron

Systematic Collaborative Reanalysis of Genomic Data Improves Diagnostic Yield in Neurologic Rare Diseases

Altres ajuts: Generalitat de Catalunya, Departament de Salut; Generalitat de Catalunya, Departament d'Empresa i Coneixement i CERCA Program; Ministerio de Ciencia e Innovación; Instituto Nacional de Bioinformática; ELIXIR Implementation Studies (CNAG-CRG); Centro de Investigaciones Biomédicas en Red de Enfermedades Raras; Centro de Excelencia Severo Ochoa; European Regional Development Fund (FEDER).Many patients experiencing a rare disease remain undiagnosed even after genomic testing. Reanalysis of existing genomic data has shown to increase diagnostic yield, although there are few systematic and comprehensive reanalysis efforts that enable collaborative interpretation and future reinterpretation. The Undiagnosed Rare Disease Program of Catalonia project collated previously inconclusive good quality genomic data (panels, exomes, and genomes) and standardized phenotypic profiles from 323 families (543 individuals) with a neurologic rare disease. The data were reanalyzed systematically to identify relatedness, runs of homozygosity, consanguinity, single-nucleotide variants, insertions and deletions, and copy number variants. Data were shared and collaboratively interpreted within the consortium through a customized Genome-Phenome Analysis Platform, which also enables future data reinterpretation. Reanalysis of existing genomic data provided a diagnosis for 20.7% of the patients, including 1.8% diagnosed after the generation of additional genomic data to identify a second pathogenic heterozygous variant. Diagnostic rate was significantly higher for family-based exome/genome reanalysis compared with singleton panels. Most new diagnoses were attributable to recent gene-disease associations (50.8%), additional or improved bioinformatic analysis (19.7%), and standardized phenotyping data integrated within the Undiagnosed Rare Disease Program of Catalonia Genome-Phenome Analysis Platform functionalities (18%)

Deficiencia de 2-metil-3-hidroxibutiril-CoA deshidrogenasa (MHBD o HSD10) e implicaciones en la enfermedad de Alzheimer

[spa] Esta tesis se basa en diagnóstico de pacientes con deficiencia de 2 metil 3 hidroxibutiril CoA deshidrogenasa (MHBD o HSD10) y en el estudio de la fisiopatología de esta enfermedad y de su implicación en la Enfermedad de Alzheimer (EA). El desarrollo de un método cuantitativo de metabolitos clave en orina y un método de análisis enzimático de la proteína HSD10 en fibroblastos cultivados, así como el análisis molecular, de los niveles de HSD10 y de los estudios patogenicidad de las mutaciones encontradas, nos ha permitido el diagnóstico de 6 pacientes y 8 portadoras, que representan el 37% de los pacientes descritos en la literatura. La herencia de esta enfermedad se halla ligada al cromosoma X. Se había descrito que el gen HSD17B10, que codifica para la proteína HSD10, se escapaba de la inactivación del cromosoma X. Sin embargo, el fenotipo bioquímico y clínico de nuestros pacientes no apoyaban este hallazgo. Mediante estudios de expresión de HSD17B10 por PCR cuantitativa se demostró que HSD17B10 no escapaba a la inactivación del cromosoma X. HSD10 es una proteína mitocondrial multifuncional que además de su papel en el metabolismo de la isoleucina y de los ácidos grasos, desempeña otras funciones en el metabolismo de hormonas esteroideas sexuales, esteroides neuroactivos, en la detoxificación de aldehídos citotóxicos y en la metabolización de cardiolipina peroxidada. La clínica neurológica de los pacientes con deficiencia de HSD10 difiere de otras deficiencias de la vía metabólica de la isoleucina. Por ello, realizamos estudios de microarrays de expresión. Obtuvimos una expresión significativamente diferente en 31 genes. Los resultados se confirmaron mediante PCR cuantitativa. La diferencia de expresión de estos genes podrían explicar los síntomas clínicos de los pacientes con deficiencia de HSD10. La proteína HSD10 parece estar implicada en la EA, debido a su interacción con el péptido β amiloide (pßA), habiéndose sugerido que dicha interacción es una de las causas de la disfunción mitocondrial en la EA. Para determinar la implicación de HSD10 en la EA se realizaron una serie de estudios en homogenados de cerebro de pacientes con EA y controles. Encontramos una disminución de la actividad de HSD10 en homogenados de cerebro de pacientes con EA y esta disminución no se debía a una disminución de los niveles de proteína, ya que el wester blot no reveló diferencias entre pacientes y controles. Se observó también que la actividad HSD10 disminuye con la progresión de la enfermedad. Por otro lado, comprobamos que la incubación de homogenados de cerebro control con pßA provocaba una inhibición de la actividad HSD10, que se rescataba al incubar con elevadas concentraciones de NAD +. Esta observación también fue corroborada en la EA. Este hecho se podía explicar por una interacción competitiva entre NAD+ y pßA, ya que ambos interaccionan con HSD10 en la misma posición aminoacídica. Por ello, al incubar con elevadas concentraciones NAD+ se inhibe la interacción pßA HSD10. Por tanto, la medición de la actividad HSD10 podría ser utilizada como diana terapéutica para la EA. Con esta finalidad, obtuvimos un sistema “in vitro” con la valoración de la proteína recombinante HDSD10 isoforma 1, que es la que expresa mayoritariamente en cerebro humano, antes y después de la incubación con pßA, con y sin adición de NAD+. Los resultados obtenidos fueron los mismos que al utilizar homogenados de cerebro humano. Por lo tanto, quedaba validado un sistema para cribar moléculas terapéuticas que pudieran inhibir la interacción pßA HSD10 y restablecer la actividad HSD10. Se probaron 117 compuestos de una librería peptídica, Coenzima Q10 y otros antioxidantes, pero no se consiguió rescatar la actividad HSD10. La actividad enzimática sólo se consiguió rescatar con NAD+ . Así, proponemos que los precursores de NAD+ podrían ser considerados una terapia coadyuvante en la EA. Estudios recientes apoyan nuestros resultados, ya que la administración de precursores de NAD+ a ratones modelo para la EA, mejoran la disfunción mitocondrial así como la cognición.[eng] This thesis is based on diagnosis of patients with 2 methyl 3 hydroxybutyryl CoA dehydrogenase (MHBD or HSD10) deficiency and the study of its pathophysiology and its involvement in Alzheimer's Disease (AD). The development of different methods for quantification of key metabolites in urine and for enzymatic analysis in cultured fibroblasts, as well as the molecular studies performed, has allowed us the diagnosis of 6 patients and 8 carriers, which represents 37% of the patients described in the literature. Expression studies of HSD17B10 demonstrated that this gen not escapes inactivation of the X chromosome, contrary to that published by other authors. The neurological symptoms of patients with deficiency HSD10 differs from other deficiencies in the isoleucine's metabolic pathway, maybe due to the alteration of other functions involved in both, brain and mitochondrial homeostasis. The expression "microarray" studies performed revealed significantly different expression in 31 genes, which could explain the clinical symptoms of the patients. The HSD10 protein appears to be involved in AD, due to their interaction with β amyloid peptide (Aβ). Studies in brain homogenates of AD patients showed decreased HSD10 activity from the early stages of the disease, which could explain the early mitochondrial dysfunction observed in AD. Furthermore, the Aβ incubation caused inhibition of HSD10 activity in control brain homogenates, which was rescued by incubating with high NAD+ concentrations. This observation was also corroborated in AD. This fact could be explained by a competitive interaction that occurs between NAD+ and Aβ. Therefore, the measurement of HSD10 activity could be used as a therapeutic target for AD. To this end, we obtained "in vitro" system to the evaluation of the HDSD10 isoform 1 recombinant protein, which is the mainly expressed in human brain, before and after incubation with Aβ, with and without addition of NAD+. The results were the same as when using human brain homogenates. Therefore, the system was validated for screening therapeutic molecules that could inhibit the Aβ HSD10 interaction and restore HSD10 activity. Among 117 compounds tested, only NAD+ was able to rescue HSD10 activity. Thus, we propose that the precursors of NAD+ could be considered an adjunctive therapy in AD. Recent studies support our results, since administration of NAD precursors mice model for AD, improve mitochondrial dysfunction and cognition

Physiopathological Bases of the Disease Caused by HACE1 Mutations: Alterations in Autophagy, Mitophagy and Oxidative Stress Response

Recessive HACE1 mutations are associated with a severe neurodevelopmental disorder (OMIM: 616756). However, the physiopathologycal bases of the disease are yet to be completely clarified. Whole-exome sequencing identified homozygous HACE1 mutations (c.240C>A, p.Cys80Ter) in a patient with brain atrophy, psychomotor retardation and 3-methylglutaconic aciduria, a biomarker of mitochondrial dysfunction. To elucidate the pathomechanisms underlying HACE1 deficiency, a comprehensive molecular analysis was performed in patient fibroblasts. Western Blot demonstrated the deleterious effect of the mutation, as the complete absence of HACE1 protein was observed. Immunofluorescence studies showed an increased number of LC3 puncta together with the normal initiation of the autophagic cascade, indicating a reduction in the autophagic flux. Oxidative stress response was also impaired in HACE1 fibroblasts, as shown by the reduced NQO1 and Hmox1 mRNA levels observed in H2O2-treated cells. High levels of lipid peroxidation, consistent with accumulated oxidative damage, were also detected. Although the patient phenotype could resemble a mitochondrial defect, the analysis of the mitochondrial function showed no major abnormalities. However, an important increase in mitochondrial oxidative stress markers and a strong reduction in the mitophagic flux were observed, suggesting that the recycling of damaged mitochondria might be targeted in HACE1 cells. In summary, we demonstrate for the first time that the impairment of autophagy, mitophagy and oxidative damage response might be involved in the pathogenesis of HACE1 deficiency

Impacto de la inclusión de pruebas de segundo nivel en el programa de cribado neonatal de Cataluña y en otros programas internacionales

Background: Newborn screening programmes (NBSP) have experienced a qualitative breakthrough due to the implementation of tandem mass spectrometry. However, the tests used give rise to false positives (FP) generating an excessive request for second samples with the consequent anxiety of the families. In order to avoid this problem several programmes have developed second-tier tests (2TT). Methods: This article presents our experience in the implementation of 2TT in the NBSP of Catalonia, as well as in other international programmes. Results: From 2004 to the present, 2TT tests have been developed for more than 30 diseases. The use of 2TT helps to decrease the FP rate and increase the positive predictive value (PPV). In the NBSP of Catalonia, the implementation of 2TT for the detection of methylmalonic and propionic acidemias, homocystinurias, maple syrup disease and citrulinaemia, has managed to increase the PPV to 95% and decrease the PF rate to less than 0.01%. In cystic fibrosis, the application of 2TT slightly increases PPV but with a significant decrease in the request for second samples and in the number of cases referred to clinical units. Conclusions: The introduction of 2TT in the NBSP allows to reduce considerably the FP, decreases the number of requested samples, as well as both anxiety and stress of the families, at the same time that the hospital costs are reduced and the PPV is increased, improving notably the efficiency of the NBSP.Fundamentos: Los programas de cribado neonatal (PCN) han experimentado un gran avance cualitativo debido a la implementación de la espectrometría de masas en tándem. Sin embargo, las pruebas utilizadas dan lugar a falsos positivos (FP) generando una excesiva solicitud de segundas muestras con la consiguiente ansiedad de las familias. Con el fin de evitar este problema diversos programas han desarrollado pruebas de segundo nivel (2TT). Métodos: En este artículo se presenta nuestra experiencia en la implementación de 2TT en el PCN de Cataluña, así como en otros programas internacionales. Resultados: Desde el año 2004 hasta la actualidad se han desarrollado pruebas de 2TT para más de 30 enfermedades. La utilización de 2TT ayuda a disminuir la tasa de FP y aumentar el valor predictivo positivo (VPP). En el PCN de Cataluña, la implementación de 2TT para la detección de acidemias metilmalónicas y propiónica, homocistinurias, jarabe de arce y citrulinemia, ha conseguido aumentar el VPP a un 95% y disminuir la tasa de FP a menos del 0,01%. En la fibrosis quística la aplicación de 2TT aumenta ligeramente el VPP pero con disminución significativa de la solicitud de segundas muestras y de los casos referidos a las unidades clínicas. Conclusiones: La introducción de los 2TT en los PCN permite reducir considerablemente los FP, disminuye el número de muestras solicitadas, así como la ansiedad y el estrés de las familias, a la vez que se reducen los costes hospitalarios y se aumenta el VPP, mejorando notablemente la eficiencia de los PCN