Evaluation of epigenetic-related gene expression (DNMT, HDAC1) in Iranian patients with systemic lupus erythematosus / Evaluación de la expresión de los genes relacionados con la epigenética (DNMT, HDAC1) en pacientes iraníes con lupus eritematoso sistémico

Background: Systemic lupus erythematosus (SLE) is an autoimmune disease in which the immune system abnormally reacts against cells and tissues leading to inflammation. Epigenetic alterations, including DNA methylation and histone modification, have critical effects on autoimmune disease and SLE pathogenesis via dysregulation of critical genes. Aims: The purpose of this study was to evaluate the epigenetic-related gene expression of DNA methyltransferase (DNMT) and histone deacetylase 1 (HDAC1) in Iranian patients with SLE. Methods: This matched case–control study included 16 people with SLE and 16 healthy people who were referred to the Rafsanjani rheumatology clinic, in southeast Iran. The expression of DNMT and HDAC1 genes was measured through a real-time PCR assay of blood samples. Results: DNMT gene expression did not differ significantly between SLE and healthy groups (P=0.21). In contrast, HDAC1 gene expression was enhanced in the SLE group, but this enhancement failed to reach statistical significance (P=0.94). Conclusion: The results of this study suggest that overexpression of HDAC1 could serve as a diagnostic for SLE disease. Additional studies with larger sample sizes are required to confirm our findings. Evaluation of other genes related to SLE disease is essential and may help to make an accurate diagnosis of the disease.(AU)

Antecedentes: El lupus eritematoso sistémico (LES) es una enfermedad autoinmune, en la cual el sistema inmunitario reacciona de manera anormal frente a las células y tejidos causantes de la inflamación. Las alteraciones epigenéticas, incluyendo la metilación del ADN y la modificación de la histona, tienen efectos críticos en la enfermedad autoinmune y la patogenia del LES, a través de la desregulación de los genes críticos. Objetivo: El objetivo de este estudio fue evaluar la expresión del gen relacionado con la epigenética de ADN metiltransferasa (DNMT) e histona deacetilasa 1 (HDAC1) en los pacientes iraníes afectados de LES. Métodos: Este estudio pareado caso-control incluyó 16 personas con LES y 16 personas sanas, derivadas a la clínica de reumatología de Rafsanjan, en el sudeste de Irán. La expresión de los genes DNMT y HDAC1 se midió mediante una PCR a tiempo real de muestras de sangre.Resultados: La expresión del gen DNMT no difirió significativamente entre los grupos de pacientes de LES y de controles sanos (p=0,21). Por contra, la expresión del gen HDAC1 se incrementó en el grupo LES, aunque dicho incremento no alcanzó significación estadística (p=0,94). Conclusión: Los resultados de este estudio sugieren que la sobreexpresión de HDAC1 podría servir para diagnosticar el LES. Son necesarios estudios adicionales con muestras de mayor tamaño para confirmar nuestros hallazgos. Es esencial la evaluación de otros genes relacionados con el LES, pudiendo ayudar a realizar un diagnóstico preciso de la enfermedad.(AU)

SUV39H1 is a prognosis and immune microenvironment-related biomarker in diffuse large B-cell lymphoma

Background The tumor microenvironment plays a crucial role in the oncogenesis and treatment of diffuse large B-cell lymphoma (DLBCL). The H3K9me3-specific histone methyltransferase Suppressor of variegation 3-9 homolog 1 (SUV39H1) is a significant gene that promotes the progression of various malignancies. However, the specific expression of SUV39H1 in DLBCL remains unclear. Methods By retrieving data from GEPIA, UCSC XENA and TCGA public databases, we observed the high expression of SUV39H1 in DLBCL. Combined with an immunohistochemical validation assay, we analyzed our hospital’s clinical characteristics and prognosis of 67 DLBCL patients. The results showed that high SUV39H1 expression was closely associated with age over 50 years (P = 0.014) and low albumin levels (P = 0.023) of patients. Furthermore, the experiments in vitro were deployed to evaluate the regulation of SUV39H1 on the DLBCL immune microenvironment. Results The results showed that high SUV39H1 expression was closely associated with age over 50 years (P = 0.014) and low albumin levels (P = 0.023) of patients. The prognostic analysis showed that the high SUV39H1 expression group had a lower disease-free survival (DFS) rate than the low SUV39H1 expression group (P < 0.05). We further discovered that SUV39H1 upregulated the expression of CD86+ and CD163+ tumor-associated macrophages by DLBCL patients’ tissues and cell experiments in vitro (P < 0.05). And SUV39H1-associated T lymphocyte subsets and cytokines IL-6/CCL-2 were downregulated in DLBCL (P < 0.05). Conclusions In summary, SUV39H1 might be not only a potential target for treating DLBCL but also a clinical indicator for doctors to evaluate the trend of disease development (AU)

Epigenetic inhibition of lncRNA GMDS-AS1 by methyltransferase ESET promoted cell viability and metastasis of hepatocellular carcinoma

Background Long noncoding RNA (lncRNAs) GMDS-AS1 has been reported as a tumor regulator in tumor growth and metastasis, but its effect in hepatocellular carcinoma (HCC) remains unclear. ESET, a histone H3K9 methyl-transferase, is involved in epigenomic regulation of tumor progression in multiple cancers. However, the correlation between ESET and lncRNA in HCC is less reported. Methods Quantitative real-time PCR (qRT-PCR) was taken to determine the expression of ESET and GMDS-AS1. Western blot was taken to determine the target protein levels of ESET and GMDS-AS1. Online database and bioinformatics analysis were used to screen abnormally expressed genes. Luciferase assay was performed to confirm the binding of GMDS-AS1 and PSMB1. Ki67 and Edu were used for evaluated the proliferation of tumor cells. ChIP assay was performed to verify the relationship between H3K9me1 and lncRNA GMDS-AS1 promoter. Transwell was taken to determine the migration and invasion ability of tumor cells. CCK-8 was used for determining the viability of tumor cells. Flow cytometry was performed to detect the cell cycle of tumor cells. Results The expression of GMDS-AS1 was decreased and the expression of ESET was increased in HCC. GMDS-AS1 inhibition contributed to tumor development, and this effect was closely related to epigenetic inhibition of GMDS-AS1 by ESET. PSMB1, a downstream target of GMDS-AS1, promoted the tumor proliferation and was negatively regulated by GMDS-AS1. Conclusion Our result demonstrates anti-tumorigenic traits of lncRNA GMDS-AS1 in HCC and explains its pattern of regulation mediated by ESET. Our work unmasked an essential role of GMDS-AS1 in HCC progression and detected a novel pathway for ESET to promote HCC (AU)

Fear stress promotes glioma progression through inhibition of ferroptosis by enhancing FSP1 stability

Purpose Patients diagnosed with cancer often suffer from emotional stressors, such as anxiety, depression, and fear of death. However, whether fear stress could influence the glioma progression is still unclear. Methods Xenograft glioma animal models were established in nude mice. Tumor-bearing mice were subjected to fear stress by living closely with cats and then their depressive behaviors were measured using an open field test. Hematoxylin and eosin staining, the TUNEL staining and immunochemical staining were used to detect the histopathological changes of tumor tissues. Gene expression profiling was used to screen the aberrant gene expression. Methylated RNA immunoprecipitation was used to identify the RNA m6A level. Gene expression was measured by western blot and real-time PCR, respectively. Results We found that fear stress promoted glioma tumor progression in mice. Fear stress-induced upregulation of METTL3 and FSP1, increased m6A level of glioma tumor tissues, and inhibited ferroptosis in glioma progression, which were reversed by knockdown of METTL3 and FSP1 in vivo. In addition, we found that when iFSP1 (a ferroptosis inducer by targeting inhibition of FSP1) was introduced to glioma cells, the cells viability of glioma significantly was decreased and ferroptosis was enhanced in glioma cells. Conclusions Fear stress-induced upregulation of METTL3 stabilized FSP1 mRNA by m6A modification, leading to tumor progression through inhibition of ferroptosis. Our study provides a new understanding of psychological effects on glioma development, and new insights for glioma therapy (AU)

Physio-pathological effects of m6A modification and its potential contribution to melanoma

Methylation of N6-adenosine (m6A) is the most prevalent internal RNA modification and is especially common among the messenger RNAs. These m6A modifications regulate splicing, translocation, stability and translation of RNA through dynamic and reversible interactions with m6A-binding proteins, namely the writers, erasers and readers. RNA methyltransferases catalyze the m6A modifications, while demethylases reverse this methylation. Deregulation of the m6A modification process has been implicated in human carcinogenesis, including melanoma—which carries one of the highest mutant rates. In this review, we provide an up-to-date summary of m6A regulation and its biological impacts on normal and cancer cells, with emphasis on the deregulation of m6A modification and m6A regulators in melanoma. In addition, we highlight the prospective potential of exploiting m6A modification in the treatment of melanoma and non-cancer diseases. (AU)

Mutations in chronic myelomonocytic leukemia and their prognostic relevance

Chronic myelomonocytic leukemia (CMML) is a hematologic malignancy that overlaps with myeloproliferative neoplasms (MPN) and myelodysplastic syndromes (MDS) and tends to transform into acute myeloid leukemia (AML). Among cases of CMML, > 90% have gene mutations, primarily involving TET2 (~ 60%), ASXL1 (~ 40%), SRSF2 (~ 50%), and the RAS pathways (~ 30%). These gene mutations are associated with both the clinical phenotypes and the prognosis of CMML, special CMML variants and pre-phases of CMML. Cytogenetic abnormalities and the size of genome are also associated with prognosis. Meanwhile, cases with ASXL1, DNMT3A, NRAS, SETBP1, CBL and RUNX1 mutations may have inferior prognoses, but only ASXL1 mutations were confirmed to be independent predictors of the patient outcome and were included in three prognostic models. Novel treatment targets related to the various gene mutations are emerging. Therefore, this review provides new insights to explore the correlations among gene mutations, clinical phenotypes, prognosis, and novel drugs in CMML (AU)

METTL3 promotes inflammation and cell apoptosis in a pediatric pneumonia model by regulating EZH2

Background: In recent times, the medical science has developed by leaps and bounds, however, the molecular mechanism of pediatric pneumonia is still unclear. Although prior researches have shown that methyltransferase-like 3 (METTL3) is up-regulated in a variety of inflammatory diseases, its role and mechanism has been rarely studied in pediatric pneumonia, and need to be defined elaborately. Objective: In this study, the related molecular mechanism of METTL3 on inflammation and cell apoptosis in a pediatric pneumonia was investigated. Materials and methods: Quantitative real-time polymerase chain reaction (qPCR) and western blot assays were employed to examine the mRNA and protein expression level of METTL3 and EZH2 in peripheral blood monocytes from pediatric pneumonia patients or cell model (WI-38). Then, qPCR and ELISA assay were applied to verify the inflammatory response in LPS-treated WI-38 cell lines after knockdown of METTL3. Besides, MTT cell viability assays, flow cytometry, and western blot assays were applied to examine the cell viability and cell apoptosis of LPS-treated WI-38 cell after knockdown of METTL3. Further, the western blot assays were employed to examine the protein expression levels of p-JAK2, JAK2, p-STAT3, STAT3, and EZH2 in LPS-treated WI-38 cell after knockdown of METTL3. Finally, ELISA and western blot were applied to verify the inflammatory response and cell apoptosis of LPS-treated WI-38 cell after knockdown of METTL3 and overexpression of EZH2. Results: In this study, the results showed that METTL3 and EZH2 were highly expressed in pediatric pneumonia patients and cell models (WI-38), respectively. Besides, downregulation of METTL3 inhibited LPS-induced inflammatory response and cell apoptosis (AU)

Characterization of a S-adenosyl-l-methionine (SAM)- accumulating strain of Scheffersomyces stipitis

S-adenosyl-l-methionine (SAM) is an important molecule in the cellular metabolism of mammals. In this study, we examined several of the physiological characteristics of a SAM-accumulating strain of the yeast Scheffersomyces stipitis (M12), including SAM production, ergosterol content, and ethanol tolerance. S. stipitis M12 accumulated up to 52.48 mg SAM/g dry cell weight. Proteome analyses showed that the disruption of C-24 methylation in ergosterol biosynthesis, a step mediated by C-24 sterol methyltransferase (Erg6p), results in SAM accumulation by S. stipitis M12 compared to the wild-type strain. A comparative proteome-wide analysis identified 25 proteins that were differentially expressed by S. stipitis M12. These proteins are involved in ribosome biogenesis, translation, the stress response, ubiquitin-dependent catabolic processes, the cell cycle, ethanol tolerance, posttranslational modification, peroxisomal membrane stability, epigenetic regulation, the actin cytoskeleton and cell morphology, iron and copper homeostasis, cell signaling, and energy metabolism (AU)

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Optimización del tratamiento con azatioprina: determinación de la actividad de tiopurina metiltransferasa y las concentraciones de metabolitos tiopurínicos / Optimising azathioprine treatment: determination of thiopurine methyltransferase activity and thiopurine metabolites

Introducción: la determinación de la enzima tiopurina metiltransferasa (TPMT) nos permite pautar la dosis inicial individualizada de azatioprina (AZA). Las determinaciones de los metabolitos tiopurínicos de la AZA, la 6-tioguanina (6-TGN) y la 6-metilmercaptopurina (6-MMP) se han descrito como nuevos marcadores de la actividad del fármaco. Objetivos: describir el fenotipo de TPMT en nuestra población y relacionar los valores de los metabolitos tiopurínicos con la actividad terapéutica y los efectos adversos. Material y métodos: se recogieron retrospectivamente los valores de TPMT de 107 pacientes y de 6-TGN y 6-MMP de 18 pacientes en tratamiento con AZA (8 con enfermedad de Crohn, 5 con colitis ulcerosa y 5 con hepatitis autoinmune). Resultados: la media de determinación de TPMT fue 20,19U/ml. Ninguno presentó actividad de TPMT menor que 5U/ml. De los 18 pacientes, 13 mostraron concentraciones subterapéuticas de 6-TGN (<235pmol/8×108 hematíes). El 45% de los pacientes mantuvieron remisión clínica. La media de concentración de 6-TGN en los pacientes en remisión fue 259pmol/8×108 hematíes frente a 209pmol/8×108 hematíes en los no respondedores (p=0,37). Hay una relación inversa (r=−0,28) entre los valores de TPMT y los de 6-TGN. En 6/18 pacientes encontramos toxicidad: 5 con leucocitopenia y uno con hiperamilasemia. Conclusiones: la determinación de TPMT y la monitorización de los metabolitos tiopurínicos nos permite optimizar tratamiento con AZA, aunque son necesarios nuevos estudios que permitan el correcto conocimiento de los intervalos de efectividad terapéutica y toxicidad (AU)

Introduction: Individualised doses of azathioprine (AZA) may be prescribed by monitoring the levels of the enzyme thiopurine methyltransferase (TPMT). The measurements of thiopurine metabolites of AZA, 6-thioguanine (6-TGN) and 6-methylmercaptopurine (6-MMP), have also been reported as new markers of AZA activity. Objectives: To describe TPMT phenotype in our population and to establish a relationship between thiopurine metabolites,and therapeutic activity and adverse effects. Material and methods: Data on TPMT were retrospectively collected from 107 patients, and 6-TGN and 6-MMP levels in 18 patients currently on treatment with AZA (Crohn’s disease 5, ulcerative colitis 5, autoimmune hepatitis 5). Results: Mean value of TPMT was 20.19U/ml. None of the patients had a TPMT activity<5U/ml. Of the 18 patients on treatment, 13 showed sub-therapeutic levels of 6-TGN (<235pmol/8×108 red blood cells). Clinical remission was maintained in 45% of patients. Mean levels of 6-TGN in patients with clinical remission were 259pmol/8×108 red blood cells versus 209pmol/8×108 red blood cells in non-responders (p=0.37). There was an inverse relationship (r=−0.28) between TPMT and 6-TGN levels. Toxic effects occurred in 6 of 18 patients, with leukopenia in 5 and hyperamylasemia in 1. Conclusions: Determination of TPMT and monitoring of thiopurine metabolites allows AZA treatment to be optimised, although further studies are necessary to establish therapeutic effectiveness and toxicity ranges (AU)

Novel 10-bp deletion in the translational attenuator of a constitutively expressed erm(A) gene from Staphylococcus epidermidis

Alterations in the erm(A) regulatory region of six clinical isolates of Staphylococcus epidermidis and one of Staphylococcus haemolyticus displaying a constitutive resistance phenotype were investigated. A novel deletion of 10 bp with respect to the corresponding sequence of Tn554 was identified in the attenuator of a constitutively expressed erm(A) gene of one of the S. epidermidis isolates. Thus far, this is the smallest deletion conferring constitutive resistance in the translational attenuator of erm(A) in a naturally occurring S. epidermidis strain of human origin (AU)

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Detección de resistencia inducible a clindamicina en aislados cutáneos de Staphylococcus spp. por métodos fenotípicos y genotípicos / Detection of inducible resistance to clindamycin in cutaneous isolates of Staphylococcus spp. by phenotypic and genotypic methods

Introducción. La resistencia de estafilococos a macrólidos, lincosamidas y estreptograminas del tipo B (antibióticos MLSB) puede ser debida a varios mecanismos de resistencia y entre ellos los dos más importantes son la expulsión activa (fenotipo MSB) y la modificación de la diana en el ribosoma (fenotipo MLSB). Este último mecanismo confiere resistencia cruzada a los 3 grupos de antimicrobianos (resistencia MLSB). La expresión fenotípica de la resistencia MLSB puede ser de carácter constitutivo (cMLSB) o inducible (iMLSB). Métodos. Se estudiaron 117 estafilococos resistentes a eritromicina procedentes de muestras cutáneas que fueron seleccionados a partir de 536 aislados clínicos de estafilococos. El estudio fenotípico se realizó mediante la técnica de difusión por doble disco. La presencia de los genes ermA, ermC, ermB y msrA implicados en la resistencia se estudiaron por reacción en cadena de la polimerasa (PCR) en tiempo real. Resultados. El fenotipo MSB fue el más frecuente, encontrándose en el 11,2% de las cepas (7,2% Staphylococcus aureus y 23% ECN) y la tasa de resistencia inducible iMLSB, fue estadísticamente significativa más alta 7,4% (5,2% en S. aureus y 14% en ECN) que la tasa de resistencia constitutiva cMLSB, 3,2% (1,7% en S. aureus y 7,4% en ECN). Todos los aislados con el fenotipo MSB presentaron el gen msrA y el gen ermC fue el más frecuentemente detectado en las cepas resistentes a clindamicina con fenotipo MLSB (constitutivo o inducible). Conclusión. La buena correlación entre los métodos fenotípicos (doble difusión con discos) y genotípicos permiten inferir el mecanismo de resistencia a eritromicina y clindamicina, seleccionar el tratamiento antimicrobiano más adecuado, así como apreciar las diferencias epidemiológicas en su distribución (AU)

Introduction. Resistance to macrolides, lincosamides and type B streptogramins (MLSB) in Staphylococcus isolates can be due to several mechanisms. The most important are an active efflux mechanism (MSB phenotype) and ribosomal target modification (MLSB phenotype); this latter mechanism confers resistance to all three groups of antimicrobials (MLSB resistance). Expression of MLSB resistance can be constitutive (cMLSB) or inducible (iMLSB). Methods. A group of 117 erythromycin-resistant Staphylococcus spp. clinical isolates from cutaneous samples were selected from 536 recent clinical isolates of this microorganism. Resistance phenotypes were determined by the double disk diffusion test. Presence of the ermA, ermC, ermB and msrA genes was detected by real time PCR. Results. The MSB phenotype was the most common, comprising 11.2% (7.2% in S. aureus and 23% in CoNS) of the erythromycin-resistant strains. The rate of iMLSB resistance was significantly higher, 7.4% (5.2% in S. aureus and 14% in CoNS), than the rate of cMLSB resistance, 3.2% (1.7% in S. aureus and 7.4% in CoNS). The msrA gene was present in all isolates with the MSB phenotype, and the ermC gene was the most common among clindamycin-resistant strains with the MLSB phenotype (constitutive or inducible). Conclusion. The good correlation between the phenotypic (disk-diffusion) and genotypic (real time PCR) methods used allows prediction of the mechanisms of erythromycin and clindamycin resistance, provides insight into the epidemiological differences in their distribution, and is an aid to selecting the most appropriate antimicrobial therapy (AU)

Streptococcus agalactiae aislados en Santa Fe, Argentina: estudio de la sensibilidad a antibióticos de uso clínico y mecanismos de resistencia a eritromicina y clindamicina / Streptococcus agalactiae isolated in Santa Fe, Argentina: antibiotic susceptibility and erythromycin-clindamycin resistance mechanisms

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Monitorización de la tiopurina metiltransferasa y de los metabolitos tiopurínicos para optimizar el tratamiento con azatioprina en la enfermedad inflamatoria intestinal / Monitoring of thiopurine methyltransferase and thiopurine metabolites to optimize azathioprine therapy in inflammatory bowel disease

La determinación de la actividad de la tiopurina metiltransferasa (TPMT) y de los metabolitos tiopurínicos (nucleótidos de la 6-tioguanina y 6-metilmercaptopurina) podría ser útil para monitorizar de forma individualizada la dosis de azatioprina (AZA) y 6-mercaptopurina (6-MP). La actividad de la TPMT en la población general sigue una distribución trimodal, en la que aproximadamente el 0,3% de los individuos son homocigotos para el alelo de baja actividad. Se ha demostrado una notable correlación entre el fenotipo o el genotipo de baja actividad de la TPMT y el riesgo de mielotoxicidad. Los pacientes con un genotipo o fenotipo homocigoto de alta actividad de la TPMT deberían recibir dosis de inmunosupresores que hayan demostrado ser claramente eficaces. Por el contrario, en los pacientes con genotipo o fenotipo homocigoto de baja actividad de la TPMT se debería contraindicar el empleo de AZA/6-MP o, en todo caso, sería obligado administrar dosis muy reducidas de estos fármacos. En cualquier caso, es importante recalcar que el déficit de TPMP explica únicamente un porcentaje de los casos de mielotoxicidad, por lo que los controles analíticos periódicos deben seguir realizándose en los pacientes que reciben AZA/6-MP, a pesar de que la función de esta enzima sea normal. Actualmente no está establecida la utilidad de determinar de forma sistemática los metabolitos tiopurínicos en los pacientes tratados con AZA/6-MP, y su cuantificación está limitada, en todo caso, a algunas circunstancias problemáticas, como la ausencia de respuesta al tratamiento tiopurínico o la aparición de efectos adversos tras éste. Se precisan estudios aleatorizados que comparen la estrategia habitual de dosificación de la AZA/6-MP (basada únicamente en el peso del paciente) frente a la monitorización individualizada (basada en la cuantificación de la actividad de la TPMT y/o de los metabolitos tiopurínicos) para po der concluir definitivamente cuál es la alternativa más adecuada

Determination of the activity of thiopurine methyltransferase (TPMT) and of thiopurine metabolites (6-thioguanine and 6-methylmercaptopurine nucleotides) could be useful for individualized monitoring of azathioprine (AZA) and 6-mercaptopurine (6-MP) doses. TPMT activity in the general population follows a trimodal distribution, in which approximately 0.3% of the population is homozygotic for the low-activity allele. A notable correlation has been observed between the low TPMP activity genotype or phenotype and the risk of myelotoxicity. Patients with a high TPMT activity genotype or homozygous phenotype should receive immunosuppressive doses that have clearly been demonstrated to be effective. In contrast, in patients with a low TPMT activity genotype or homozygous phenotype, the use of AZA/6-MP should be contraindicated or only very small doses should be administered. Importantly, TPMP deficiency explains only some cases of myelotoxicity and consequently periodic laboratory testing should be performed in patients receiving AZA/6-MP, even though TPMP function may be normal. Currently, the utility of routine thiopurine metabolite determinations in patients undergoing AZA/6-MP therapy has not been established and this practice should be limited to specific situations such as lack of response to thiopurine therapy or the occurrence of thiopurine-related adverse effects. Randomized trials comparing the routine strategy of AZA/6-MP dosing (based exclusively on the patient's weight) versus individualized monitoring (based on quantification of TPMP activity and/or thiopurine metabolites) are required before definitive conclusions on the most effective alternative can be drawn

Diagnóstico y tratamiento de los síndromes de deficiencia de creatina cerebral / Diagnosis and treatment of brain creatine deficiency syndromes

Aim. To review the clinical, biochemical and genetic aspects of brain creatine deficiency syndromes, as well as thetherapeutic options available. Development. Brain creatine deficiency syndrome has recently been described as a series ofinborn errors of metabolism that affect the synthesis and transport of creatine. Three metabolic defects are known: two affectsynthesis –guanidinoacetate methyltransferase (GAMT) and arginine:glycine amidinotransferase (AGAT)– and one affectsthe transport of creatine. Clinically, these patients can display mental retardation, language disorders, epilepsy, autisticbehaviour, neurological impairment and movement disorders. After the clinical selection, the different defects can beidentified by a biochemical study involving the analysis of metabolites in biological fluids (guanidinoacetate and creatine/creatinine ratio). Before continuing with the molecular studies, it is important to confirm the deficiency of brain creatine bymeans of magnetic resonance imaging with spectroscopy. Diagnostic confirmation of AGAT and GAMT deficits is carried outby determining the enzymatic activity in fibroblasts or lymphoblasts, or the incorporation of creatine in the case of studiesof transport defects. The study of mutations in AGAT, GAMT (autosomal recessive inheritance) and SLC6A8 (X-linked)genes completes the diagnosis. Conclusions. Brain creatine deficiency syndromes are mainly associated to mental retardationand autism. GAMT and AGAT deficiencies respond to treatment with creatine, whereas patients with transport defects donot respond to this therapy; new therapeutic approaches are therefore being evaluated for this disease

Objetivo. Revisar los aspectos clínicos, bioquímicos ygenéticos, y las opciones terapéuticas en los síndromes de deficienciade creatina cerebral. Desarrollo. Recientemente se ha descrito elsíndrome de deficiencia de creatina cerebral como un conjunto deerrores innatos del metabolismo que afectan a la síntesis y al transportede creatina. Se conocen tres defectos metabólicos: dos afectana la síntesis –deficiencia de guanidinoacetato metiltransferasa(GAMT) y de arginina-glicina amidinotransferasa (AGAT)– y unoal transporte de creatina. Clínicamente, estos pacientes pueden presentarretraso mental, trastornos del lenguaje, epilepsia, comportamientoautista, deterioro neurológico y trastornos del movimiento.Tras la selección clínica, el estudio bioquímico mediante análisis demetabolitos en fluidos biológicos (guanidinoacetato y relación creatina/creatinina) permite identificar los diferentes defectos. Antes decontinuar con los estudios moleculares, es importante confirmar la deficiencia cerebral de creatina mediante resonancia magnética conespectroscopia . La confirmación diagnóstica en las deficiencias deAGAT y GAMT se realiza determinando la actividad enzimática enfibroblastos o linfoblastos, o la incorporación de creatina para elestudio del defecto de transporte. El estudio de las mutaciones en losgenes AGAT, GAMT (herencia autonómica recesiva) y SLC6A8(ligado al cromosoma X) completa el diagnóstico. Conclusiones.Los síndromes de deficiencia de creatina cerebral están asociadosprincipalmente al retraso mental y al autismo. Las deficiencias deGAMT y AGAT responden al tratamiento con creatina, mientrasque los pacientes con defectos en el transporte no responden a estaterapia, por lo que se están evaluando nuevas aproximaciones terapéuticaspara esta enfermedad

Aumento de la resistencia a macrólidos mediada por metilasas en Streptococcus pyogenes en un hospital pediátrico de Barcelona / Increasing methylase-mediated resistance to macrolides in Streptococcus pyogenes in a children's hospital in Barcelona (Spain)

Introduction. The genetic mechanisms and changes in resistance of Streptococcus pyogenes to clarithromycin and clindamycin were studied in 480 strains from a children's hospital in Barcelona (1996-2003). Results. There was a progressive increase of strains with the MLSB phenotype (55.6% of resistant strains in 2002) and a relative decrease in the M phenotype. The overall rate of macrolide resistance was 29.8%, with an increase from 27.4% in the 1996-2001 period to 35.8% in the 2002-2003 period. The MefA gene was detected in M phenotype strains, the ermB gene in constitutive MLSB strains and the ermTR gene in some inducible MLSB strains. Conclusion. The increase of the resistance and the changes in the implied mechanisms reduce the effectiveness of macrolides and clindamycin as an alternative treatment

Introducción. Estudiamos los mecanismos genéticos y la evolución de la resistencia de S. pyogenes a claritromicina y clindamicina (1996-2003) en 480 aislamientos pediátricos de un hospital de Barcelona. Resultados. Se observa un aumento progresivo de cepas con fenotipo MLSB (55,6% de los aislamientos resistentes en 2002) y una disminución relativa del fenotipo M. El porcentaje global de resistencia a macrólidos fue del 29,8% (27,4% en el período 1996-2001 y 35,8% en 2002-2003). Se detectó el gen mefA en las cepas con fenotipo M, el gen ermB en las cepas con fenotipo MLSB constitutivo y el gen ermTR en algunas cepas con fenotipo MLSB inducible. Conclusión. El aumento de la resistencia y los cambios en los mecanismos implicados reducen la efectividad de macrólidos y clindamicina como tratamiento alternativo (AU)

Actividad de la tiopurina metiltransferasa en la enfermedad inflamatoria intestinal. Un estudio en 7.046 pacientes españoles / Thiopurine methyltransferase activity in the inflammatory bowel disease. A study on 7046 Spanish patients

Fundamento y objetivo: El objetivo del presente estudio es describir la actividad enzimática de la tiopurina metiltransferasa (TPMT) en un grupo muy numeroso de pacientes españoles con enfermedad inflamatoria intestinal (EII), evaluar el efecto de algunas variables sobre dicha actividad y conocer la proporción de pacientes con baja actividad y, por tanto, mayor riesgo de mielotoxicidad por azatioprina/6-mercaptopurina. Pacientes y método: Se determinó la actividad de TPMT mediante un método radioquímico en pacientes con EII. La asociación entre diversas variables y la actividad de TPMT se estudió mediante regresión lineal múltiple. Resultados: Se incluyó a 7.046 pacientes, el 70% con enfermedad de Crohn, el 22% con colitis ulcerosa y un 8% con colitis indeterminada. El valor medio de TPMT fue de 20 U/ml (extremos: 0-46). La distribución de actividad de TPMT fue: un 0,5% con valores bajos (= 13,8). Los valores de TPMT no siguieron una distribución normal (p < 0,001). En el estudio univariante se demostraron diferencias estadísticamente significativas (p < 0,001), aunque de dudosa relevancia clínica al ser mínimos, en los valores de TPMT en función de la edad, el sexo, el tipo de enfermedad y el tratamiento con azatioprina/6-mercaptopurina. En el estudio multivariante, el sexo y el tratamiento con 5-aminosalicilatos, glucocorticoides y azatioprina/6-mercaptopurina se asoció significativamente con la actividad de TPMT. Conclusiones: El 0,5% de los pacientes españoles con EII tiene una baja actividad enzimática de TPMT (< 5 U/ml, lo que indica un mayor riesgo de mielotoxicidad por azatioprina/6-mercaptopurina), una cifra similar a la descrita en otros países. Los diversos fármacos empleados en el tratamiento de la EII, como los 5-aminosalicilatos o la azatioprina/6-mercaptopurina, no parecen modificar de forma clínicamente relevante dicha actividad enzimática

Background and objective: Our objective was to assess the activity of thiopurine methyltransferase (TPMT) in a very large number of Spanish patients with inflammatory bowel disease (IBD), to evaluate the influence of several variables (including azathioprine or 6-mercaptopurine) on that activity, and to know the proportion of patients with low TPMT activity and therefore high risk of myelotoxicity when treated with these drugs. Patients and method: TPMT activity in red blood cells (RBCs) was measured by a radiochemical method. The association between several variables and TPMT values was assessed by multiple lineal regression. Results: 7046 patients were included (mean age: 37 years; 53% males): 70% with Crohn's disease, 22% with ulcerative colitis, and 8% with indeterminate colitis. Mean TPMT value was 20 (6) U/ml RBCs (minimum 0 and maximum 46). TPMT activity distribution was as follows: low levels (= 13.8), 88.4%. TPMT values did not follow a normal distribution (p < 0.001). In the univariate study, statistically significant differences (p < 0.001), yet of doubtly clinical significance because its minimal magnitude, were demonstrated in TPMT values depending on age, sex, type of disease, and treatment with azathioprine/6-mercaptopurine. In the multivariate study, the variables associated with TPMT activity were: sex, treatment with 5-aminosalicylates, steroids and azathioprine/6-mercaptopurine. Conclusions: This study shows that 0.5% of the Spanish patients with IBD have low TPMT activity (< 5 U/ml RBCs), a figure similar to that reported in other countries, these patients being at higher risk of myelotoxicity when treated with azathioprine or 6-mercaptopurine. The drugs usually prescribed for the treatment of IBD, including 5-aminosalicylates and azathioprine/6-ercaptopurine, do not seem to modify in a clinically relevant manner TPMT activity

Actividad eritrocitaria de tiopurina metiltransferasa y tratamiento con tiopurinas en la enfermedad inflamatoria intestinal / Erythrocyte activity of TPMT and treatment with thiopurines in inflammatory bowel disease

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Actividad de la tiopurina metiltransferasa en pacientes con hepatitis autoinmune / Thiopurine methyltransferase activity in patients with autoimmune hepatitis

FUNDAMENTO Y OBJETIVO: La determinación de la actividad de la tiopurina metiltransferasa (TPMT) sirve para controlar de forma individualizada la dosis de azatioprina con la intención de identificar a los pacientes con riesgo de mielotoxicidad, pero la distribución de la actividad enzimática en los pacientes con hepatitis autoinmune en concreto se desconoce. Nuestro objetivo fue describir la actividad de la TPMT en un grupo de más de 200 pacientes con hepatitis autoinmune y evaluar el posible efecto de algunas variables (entre las que destaca el tratamiento con azatioprina) sobre dicha actividad. PACIENTES Y MÉTODO: Se determinó, mediante un método radioquímico, la actividad de la TPMT en los eritrocitos de pacientes con hepatitis autoinmune procedentes de 31 hospitales españoles. Se estudió la relación entre los valores de TPMT y diversas variables demográficas, así como su correlación con el tratamiento con azatioprina. RESULTADOS: Se incluyeron 209 pacientes (80 por ciento mujeres, edad media de 50 años, el 39 por ciento recibía azatioprina). El valor medio de TPMT fue de 20,7 U/ml hematíes (mínimo de 0 y máximo de 39). Los valores de TPMT se ajustaron a una distribución normal. La proporción de pacientes con TPMT con valores bajos (< 5 U/ml), intermedios (5-13,7 U/ml) y altos ( 13,8 U/ml) fue, respectivamente, del 1, 9 y el 90 por ciento. En el análisis multivariante no se demostraron diferencias al comparar los valores medios de TPMT en función de la edad, el sexo o el tratamiento previo con azatioprina. CONCLUSIONES: La actividad de la TPMT en los pacientes con hepatitis autoinmune sigue una distribución semejante a la descrita en otras poblaciones (esto es, aproximadamente un 1 por ciento de los pacientes tiene valores bajos y un 9 por ciento, intermedios) y no depende de la edad, del sexo ni del tratamiento concomitante con azatioprina. (AU)

Actividad de la tiopurina metiltransferasay mielotoxicidad debida a azatioprina y 6-mercaptopurinaen pacientes con enfermedad inflamatoria del intestino / Thiopurine methyltransferase activity and myelosuppression in inflammatory bowel disease patients treated with azathioprine and 6-mercaptopurine

FUNDAMENTO Y OBJETIVO: Evaluar si existe una relación entre la actividad de la tiopurina metiltransferasa (TPMT) y la incidencia de efectos adversos, especialmente mielotoxicidad, en los pacientes con enfermedad inflamatoria del intestino tratados con azatioprina (AZA) o 6-mercaptopurina (6-MP).PACIENTES Y MÉTODO: Se determinó mediante un método radioquímico la actividad de TPMT en los eritrocitos de pacientes con enfermedad inflamatoria del intestino que habían recibido o estaban recibiendo tratamiento con AZA o 6-MP (n = 97) y en los que no habían sido tratados nunca con dichos fármacos (n = 37). Se estudió la relación entre diversas variables y los valores de TPMT, y se evaluó la correlación entre estos valores y la incidencia de efectos adversos. RESULTADOS: El valor medio (DE) de TPMT fue de 20,8 (5) U/ml hematíes (mínimo, 7,8; máximo, 32,7). No hubo ningún paciente con valores bajos (inferiores a 5 U/ml) de TPMT, el 9 por ciento tuvo concentraciones intermedias (entre 5 y 13,7 U/ml), y en el 91 por ciento se evidenciaron concentraciones elevadas (iguales o mayores de 13,8 U/ml). No se demostraron diferencias al comparar los valores de TPMT en función de las diversas variables consideradas (edad, sexo, tabaco, peso, tipo de enfermedad inflamatoria del intestino, tratamiento con 5-aminosalicilatos, esteroides o AZA/6-MP). Se describieron efectos adversos en 13 de los 97 pacientes (13 por ciento) que recibían AZA/6-MP (neutropenia en el 1 por ciento y pancitopenia en el 3 por ciento). Ninguno de los pacientes con efectos adversos tuvo concentraciones de TPMP anormalmente bajas (inferiores a 5 U/ml), ni siquiera intermedias (5-13,7 U/ml). No se demostraron diferencias al comparar los valores medios de TPMT entre los pacientes que refirieron efectos secundarios y los que no, tanto en general como al considerar la mielotoxicidad en concreto. CONCLUSIONES: En este estudio no se ha podido confirmar la utilidad de la determinación de la actividad de la TPMT para identificar a los pacientes con enfermedad inflamatoria del intestino y riesgo de mielotoxicidad debida a AZA o 6-MP. Los controles analíticos periódicos deben seguir realizándose en estos pacientes a pesar de que la actividad enzimática de la TPMT sea normal (AU)