Tuberculose chez les enfants de 0-14 ans: résistance primaire de Mycobacterium tuberculosis aux antituberculeux et variants génétiques à Kinshasa / Tuberculosis in children aged 0-14: primary resistance of Mycobacterium tuberculosis to antituberculosis drugs and genetic variants in Kinshasa

Dans les régions endémiques y compris la République Démocratique du Congo, les enfants sont susceptibles d'être exposés à la tuberculose (TB) par un contact dans l'entourage. L'absence de diagnostic peut avoir des conséquences dévastatrices. L'objectif de la présente étude était de déterminer la fréquence de TB, la résistance primaire des souches de Mycobacterium tuberculosis aux antituberculeux ainsi que des variants génétiques. Méthodes. Cette étude transversale et descriptive a été réalisée, entre juin 2011 et décembre 2017, à Kinshasa chez les enfants présumés TB. Les enfants ayant les signes évocateurs de TB figurant dans la tranche d'âge de 0-14 ans étaient inclus. Les échantillons ont été examinés par le Ziehl et mis en culture sur le milieu de Löwenstein-Jensens. Les souches étaient testées aux antituberculeux par la technique des proportions et typées par Spoligotyping. La comparaison des proportions a été faite à l'aide du test de chi-carré de Pearson. Résultats. Quarante-huit souches de Mycobacterium tuberculosis (15,4 %) ont été isolées. Dix souches (20,8%) étaient résistantes à au moins un antituberculeux plus fréquemment à l'INH. Le génotype LAM (66,7 %) et Haarlem (33,3%) était observé. Conclusion. La recherche active de TB infantile confirme qu'elle est relativement fréquente et est résistante à au moins un antituberculeux (surtout à l'INH).

Variantes genéticas frecuentes del factor von Willebrand: su influencia en el laboratorio y la clínica / Frequent genetic variants of von Willebrand factor: its influence in the laboratory and clinic

El factor von Willebrand (VWF) es una glucoproteína altamente polimórfica. Se describen aquí diferentes variantes genéticas asintomáticas altamente frecuentes, sus influencias sobre los estudios fenotípicos, en los niveles plasmáticos del mismo, y por consiguiente en diferentes entidades clínicas. Se detallan también variaciones en la frecuencia alélica según las etnias analizadas. El objetivo de este trabajo fue alertar sobre la necesidad de conocer la frecuencia de los polimorfismos en la población normal para evitar posibles conclusiones erróneas al momento del hallazgo de cambios no previamente reportados en la literatura científica.

The von Willebrand factor (VWF) is a highly polymorphic glycoprotein. Several frequent asymptomatic genetic variants, their influences on phenotypic studies, on the plasma levels of VWF, and therefore in different clinical entities are described here. Variations in allele frequency in different ethnic groups analyzed are also detailed. The aim of this study was to highlight the need to know the frequency of polymorphisms in the normal population to avoid possible erroneous conclusions at the time of finding genetic variants not previously reported in the scientific literature.

O fator von Willebrand (VWF) é uma glicoproteína altamente polimórfica. Diversas variantes genéticas assintomáticas muito frequentes são descritas aqui, suas influências em estudos fenotípicos, nos níveis plasmáticos de VWF e, portanto, em diferentes entidades clínicas. Variações na frequência alélica também são detalhadas segundo diferentes grupos étnicos analisados. O objetivo desse trabalho é alertar sobre a necessidade de conhecer a frequência dos polimorfismos na população normal, a fim de evitar possíveis conclusões errôneas no momento de encontrar variações genéticas não relatadas anteriormente na literatura científica.

Utilidad del gen SLCO1B1 como marcador de interés en la farmacogenómica de las estatinas / SLCO1B1 gene utility as a marker of interest in the pharmacogenomics of statins

Resumen Las enfermedades cardiovasculares son la principal causa de muerte en el mundo. Fármacos hipolipemiantes como las estatinas son la primera alternativa en la prevención primaria de eventos cardiovasculares, ictus cerebrales y procedimientos de revascularización. Estos fármacos son inhibidores de la enzima HMG-CoA reductasa, la cual regula la velocidad de la síntesis del colesterol y además aumenta la captación hepática del mismo por la vía del receptor de las LDL. El polipéptido transportador de aniones orgánicos 1B1 (OATP1B1) codificado por el gen SLCO1B1 es uno de los transportadores de captación y eflujo hepático de las estatinas. Por medio de estudios de asociación de genomas completos se han reportado diferentes SNPs dentro del gen SLCO1B1 con capacidad de reducir la captación de estatinas mediada por OATP1B1, por lo que las variaciones en la secuencia de este gen influyen en la farmacocinética y farmacodinámica de estos medicamentos, llegando a causar una condición conocida como miopatía inducida por estatinas. En la actualidad, genes que afectan las terapias cardiovasculares, así como los avances actuales en el campo de las pruebas diagnósticas basadas en la secuenciación de los mismos, ofrecen la posibilidad de revolucionar el diagnóstico y el tratamiento con el fin de validar el riesgo de predicción, pronóstico, prevención y manejo de pacientes con riesgo de enfermedades cardiovasculares, lo cual conducirá al desarrollo de nuevas formas de tratamientos médicos.

Abstract Cardiovascular diseases are the main cause of death in the world. Lipid-lowering drugs like statins are the first alternative in the primary prevention of cardiovascular events, strokes, and revascularisation procedures. These drugs are HMG-CoA reductase inhibitors, which regulate the rate of cholesterol synthesis, as well as increase its liver uptake via the LDL receptor pathway. The organic anion transporter polypeptide 1B1 (OATP1B1) coded by the solute carrier organic anion transporter 1B1 (SLCO1B1) gene is one of the hepatic influx and efflux transporters of statins. In genome-wide association studies (GWAS) different single nucleotide polymorphisms (SNPs) have been reported within the SLCO1B1 gene that are able to reduce the statin uptake mediated by OATP1B1. This suggests that the variations in the sequencing of this gene have an influence on the pharmacokinetics and pharmacodynamics of these drugs, leading to a condition known as statin-induced myopathy. Genes that affect cardiovascular treatments, as well as the current advances in diagnostic tests based on their sequencing, now offer the possibility of revolutionising their diagnosis and treatment. They could be used with the aim of validating risk prediction, prognosis, prevention, and management of patients with a risk of cardiovascular diseases, and will lead to the development of new forms of medical treatments.

Caracterização funcional in vitro de variantes no gene PCSK9 identificadas em pacientes com Hipercolesterolemia Familial / In vitro functional characterization of PCSK9 variants identified in patients with Familial Hypercholesterolemia

A Hipercolesterolemia Familial (HF) é uma doença genética do metabolismo das lipoproteínas, caracterizada pelo aumento do colesterol plasmático, transportado principalmente pela lipoproteína de baixa densidade (LDL). A HF é causada principalmente por mutações nos genes LDLR, APOB e PCSK9. As mutações conhecidas na PCSK9 podem levar ao aumento ou diminuição da função proteolítica da proteína, as quais são associadas ao aumento ou diminuição da LDL-c plasmática, respectivamente. Com o projeto genoma humano surgiram novos métodos de sequenciamento, o que resultou em um grande número de novas variantes genéticas relacionadas à HF. Entretanto, os mecanismos pelos quais essas variantes influenciam na concentração do colesterol e sua interferência na resposta terapêutica não estão totalmente elucidados. O objetivo do presente trabalho foi avaliar in vitro o efeito de variantes na região codificadora e reguladora do gene PCSK9 identificadas em pacientes HF utilizando sequenciamento de nova geração. Para a caracterização funcional das variantes na região codificadora da PCSK9, primeiramente foi avaliado o impacto dessas variantes na interação PCSK9-LDLR via Docking molecular. Células HEK293FT foram transfectadas com as diferentes construções da PCSK9, e posteriormente, foram utilizadas em ensaios para avaliar a atividade do LDLR e a internalização de LDL por citometria de fluxo. Para as variantes na região reguladora da PCSK9, foi realizado uma predição in silico do possível efeito de variantes na região 3UTR na ligação de miRNAs. A avalição da interação entre os miRNAs preditos, e a região 3UTR da PCSK9, e o possível impacto nessa interação na presença de variantes na região 3UTR, foi realizada em células HEK293FT transfectadas com um plasmídeo contendo a 3UTR da PCSK9 e um gene repórter da Gaussia luciferase, juntamente com um plasmídeo de expressão contendo os miRNAs de interesse. Foi também estudado o efeito dos miRNAs preditos sobre a expressão, RNAm e proteína, da PCSK9 via RT-qPCR e Western blot, em células HepG2. Foram identificadas 9 variantes na região codificadora da PCSK9, e duas, E32K e R469W, foram selecionadas para os ensaios posteriores. Para a R469W foi observada uma possível alteração conformacional a qual poderia aumentar a afinidade da PCSK9 pelo LDLR. Para a E32K, uma possível associação com HF foi observada em uma família brasileira com ascendência japonesa. As variantes E32K e R469W apresentaram uma redução na atividade do LDLR de 5 e 11%, respectivamente em comparação a PCSK9-WT. Entretanto, não foram observadas reduções estaticamente significativas na atividade do LDLR e na internalização da LDL em células transfectadas com ambas as variantes. Dez variantes foram encontradas na região 3UTR da PCSK9, entre elas três foram selecionadas por impactar a ligação de quatro miRNAs. Nossos dados demonstraram uma redução significativa na expressão da PCSK9 em células HepG2 transfectadas com os miR-4721 e miR-564 (p=0,036 e p=0,010, respectivamente). Porém, não foi observada diferenças na expressão da luciferase em células transfectadas com esses miRNAs, não sendo possível validar a interação miRNA-RNAm. As variantes no gene PCSK9 identificadas no nosso estudo podem não explicar individualmente o fenótipo HF, mas podem contribuir para a severidade da doença juntamente com outras variantes em outros genes

Familial Hypercholesterolemia (FH) is a genetic disorder of lipoprotein metabolism, characterized by elevated plasma cholesterol levels, mostly carried by low-density lipoprotein (LDL). FH is mainly caused by mutations in three genes, LDLR, APOB, and PCSK9. Gain-of-function mutations in PCSK9 reduce LDL receptor levels, resulting in high levels of LDL cholesterol in the plasma. Loss-of-function mutations lead to higher levels of the LDL receptor, resulting in lower LDL cholesterol levels. The Human Genome Project led to a faster technological development related to sequencing methods, which allowed identifying many novel variants associated with FH. However, the mechanisms by which these variants influence cholesterol levels and their interference in therapeutic response are not fully understood. The aim of the present study was to perform an in vitro characterization of the effect of PCSK9 variants identified in FH patients using Next-Generation Sequencing. For the functional characterization of variants in the coding region of PCSK9, the impact of these variants on PCSK9-LDLR interaction was evaluated by molecular docking. HEK293FT cells were transiently transfected with different PCSK9 constructs, and the amount of cell surface LDLR and LDL internalization were determined by flow cytometry. For the variants in PCSK9 3UTR region, an in silico prediction of PCSK9 3UTR variants in miRNA seed regions and target sites was performed. To determine whether the predicted miRNAs directly interact with PCSK9 3UTR region, HEK293FT cells were co-transfected with a vector containing a PCSK9 3'UTR region and a Gaussia luciferase reporter gene, together with an expression plasmid containing the miRNAs of interest. The effect of the predicted miRNAs on the expression of PCSK9 was evaluated using RT-qPCR and Western blot in HepG2 cells transiently transfected with miRNA mimics. Nine missense variants were identified in PCSK9 gene. E32K e R469W were chosen for further analysis. For R469W, a possible conformational change was observed that could increase the affinity of PCSK9 for LDLR, when compared to the wild-type. For E32K, a possible association with FH in a Brazilian family with Japanese ancestry was observed. E32K and R469W had a 5% and 11% decreased level of cell surface LDLR, respectively, as compared with WT-PCSK9. However, no significant reduction in the number of cell surface LDLR and LDL internalization was observed in transfected cells for both variants. Ten variants were found in PCSK9 3'UTR region, of which three were selected for affecting the binding of four miRNAs. Our data demonstrated a significant downregulation of PCSK9 in cells transfected with miR-4721 and miR-564 miRNA mimics, compared to cells transfected with a scramble control (p=0,036 and p=0,010, respectively). However, no differences in luciferase expression were observed in cells transfected with these miRNAs, therefore, it was not possible to experimentally validate miRNA-mRNA interaction. PCSK9 variants found in our study may not fully explain FH phenotype but may contribute to the severity of the disease together with other variants in other genes

Pharmacogenetic implications in the management of metabolic diseases in Brazilian populations

Dyslipidemia, diabetes, obesity and hypertension are common metabolic diseases. In the last decades, unhealthy lifestyle and aging have leads to an increased incidence of these diseases, increasing morbidity and mortality by cardiovascular causes. The treatment of metabolic diseases includes life-style interventions as healthy diet and physical exercise, as well as pharmacological interventions. Several drugs are available for the management of metabolic diseases including among others lipid-lowering antidiabetics and antihypertensive drugs. Variability in response to these drugs is influenced by both genetic and non-genetic factors. Polymorphisms in genes related to drug pharmacokinetics and pharmacodynamics have been shown to influence drug efficacy and safety. This review is focused on pharmacogenetic studies related to the management of metabolic diseases in samples of the Brazilian population. Associations of variants in drug metabolizing enzymes and transporters, drug target and metabolism-related genes with the efficacy and safety of lipid-lowering, antidiabetic and antihypertensive drugs are described. Most pharmacogenetic studies in Brazil have focused in pharmacological response to a small group of drugs, as statins and some antihypertensives, while there are almost no studies on antidiabetic and antiobesity drugs. Some studies reported significant associations of gene polymorphisms with drug response confirming previous data from other populations, whereas other works did not replicate, which may relay on the genetic admixture of our population. In conclusion, further studies are necessary considering larger sample sizes, new unexplored drugs and more genetic variants to obtain stronger conclusions to explore clinical applications of pharmacogenetic studies in our population.

Comment about "Randomized cross-over clinical trial comparing two pharmacokinetic models of propofol using entropy indices" / Comentario acerca de «Ensayo clínico cruzado y aleatorizado para comparar 2 modelos farmacocinéticos de propofol usando índices de entropía¼

The article, "Clinical cross-section, randomized clinical trial comparing two pharmacokinetic propofol models using entropy indexes",1 published in the July-September 2016 journal, although an interesting and novel idea, it seems to me that a big mistake was made in the study's clinical design, that totally invalidates the results.

El artículo, "Clinical cross-section, randomized clinical trial comparing two pharmacokinetic propofol models using entropy indexes",1 publicado en la revista de julio-septiembre de 2016, aunque es una idea interesante y novedosa, me parece que se cometió un gran error en el diseño clínico del estudio, que invalida totalmente los resultados.

High Prevalence of ITPA Alleles Associated with Ribavirin-Induced Hemolytic Anemia Among Mexican Population

ABSTRACT Background. The prevalence of two functional polymorphisms (rs1127354 and rs7270101) of the inosine triphosphatase (ITPA) gene associated with ribavirin-induced hemolytic anemia (RIHA) during antiviral therapy for hepatitis C virus (HCV) infection varies by ethnicity. In Mexico, the distribution of these polymorphisms among Native Amerindians (NA) and admixed population (Mestizos) is unknown. This study aimed to determine the prevalence of the ITPA polymorphisms among healthy NA and Mestizos, as well as in HCV patients from West Mexico. Material and methods. In a cross-sectional study, 600 unrelated subjects (322 Mestizos, 100 NA, and 178 treatment-naïve, HCV-infected Mestizos patients) were enrolled. A medical history was registered. ITPA genotype was determined by Real-Time PCR. Fst-values and genetic relatedness between study and reference populations were assessed. Results. The frequency of the risk genotypes rs1127354CC and rs7270101AA was higher among NA (98-100%) than in Mestizos (87-92.9%), (p < 0.05). The NA presented the highest prevalence of the rs1127354CC genotype reported worldwide. The Fst-values revealed a genetic relatedness among Mexican NA, South Americans and African populations (p > 0.05). The frequency of the predicted risk for RIHA was higher among NA (98%) than in Mestizos (80.5%) and HCV-infected patients (81.5%) (p < 0 .01). The CC/AA alleles were associated with lower values of total bilirubin, aspartate/alanine aminotransferases, and aspartate-to-platelet-ratio-index score among HCV-patients. Conclusion. A high prevalence of the ITPA polymorphisms associated with RIHA was found in Mexican NA. These polymorphisms could be a useful tool for evaluating potential adverse effects and the risk or benefit of antiviral therapy in Mexicans and other admixed populations.

Regulação epigenética da expressão gênica de Schistosoma mansoni induzida por inibidor de histona deacetilase / Epigenetic regulation of gene expression in Schistosoma mansoni induced by histone deacetilase inhibitor

A esquistossomose é um grave problema de saúde pública, com alta mortalidade e morbidade em países endêmicos, causada pelo verme trematódeo do gênero Schistosoma. O praziquantel é a única droga disponível para tratamento da doença, é usada em larga escala para tratamento de populações de áreas endêmicas, porém não previne a reinfecção e tem efeito somente em vermes adultos. Drogas estudadas em câncer como inibidores de histona deacetilases (iHDACs) modificam o padrão epigenético da célula desencadeando a morte celular, e em Schistosoma mansoni já foi mostrado que a inibição de HDACs além de aumentar a acetilação de histonas alterou o fenótipo de miracídios e provocou morte em esquistossômulos e vermes adultos. O presente estudo investigou o efeito do iHDAC Trichostatin A (TSA) na regulação da transcrição gênica em esquistossômulos, detectando por meio de ensaios de microarray centenas de genes diferencialmente expressos, relacionados a replicação de DNA, metabolismo e complexos modificadores de histonas. A inibição de HDAC em vermes adultos levou a um aumento da acetilação nas marcas de histonas H3K9ac, H3K14ac e H4K5ac relacionadas à indução de transcrição. Com imunoprecipitação de cromatina seguida de PCR (ChIP-qPCR) detectou-se o aumento de deposição de H3K9ac e H3K14ac na região promotora de genes com expressão aumentada ou diminuída, porém a marca de repressão H3K27me3 não sofreu alteração na região promotora de nenhum gene analisado. Análises adicionais indicaram um conjunto de genes diferencialmente expressos que codificam proteínas histone readers, que fazem parte de complexos modificadores de histonas, como EED capaz de identificar a marca de repressão H3K27me3 e regular a atividade de EZH2, apontando um novo alvo terapêutico. O efeito sinérgico entre iHDAC e um iEZH2 foi testado e detectou-se o aumento da mortalidade de esquistossômulos. A estrutura de SmEZH2 foi modelada por homologia e usada para análises computacionais que sugeriram uma alta afinidade de ligação de SmEZH2 com o iEZH2, abrindo uma perspectiva de desenvolvimento de novas drogas específicas para tratamento da esquistossomose

Schistosomiasis is a serious public health problem, with high mortality and morbidity in endemic countries, caused by trematode worms of the genus Schistosoma. Praziquantel is the only available drug for treatment of the disease; it is used extensively to treat populations in endemic areas, but does not prevent reinfection and is effective only in adult worms. Drugs studied in cancer as histone deacetylase inhibitors (iHDACs) modify the epigenetic status of the cell, triggering cell death, and it has been shown in Schistosoma mansoni that inhibition of HDACs increase histone acetylation, alter the phenotype of miracidia and cause death in schistosomules and adult worms. The present study investigated the effect of iHDAC Trichostatin A (TSA) on the regulation of gene transcription in schistosomules, detecting by means of microarray assays hundreds of differentially expressed genes related to DNA replication, metabolism and histone remodeling complexes. Inhibition of HDAC in adult worms led to an increase in histone acetylation marks H3K9ac, and H3K14ac H4K5ac related to transcriptional induction. With chromatin immunoprecipitation followed PCR (ChIP-qPCR) we detected an increased deposition of H3K9ac and H3K14ac at the promoter region of genes with increased or decreased expression, but the repressive mark H3K27me3 was not changed at all analyzed gene promoter regions. Additional analysis indicated a set of differentially expressed genes that encode histone reader proteins that are part of histone modifier complexes such as EED, which is able to identify the repression mark H3K27me3 and to regulate EZH2 activity, pointing to a new therapeutic target. The synergistic effect between iHDAC and one iEZH2 has been tested and found to cause an increase in schistosomules mortality. The SmEZH2 structure was modeled by homology and used for computational analyses, which suggested a high affinity binding of SmEZH2 with iEZH2, opening the opportunity for development of new specific drugs for treatment of schistosomiasis

Farmacocinética y penetración en líquido tisular de cefepime administrado en conejos hipertérmicos / Pharmacokinetics and penetration into tissue fluid of cefepime administered to hyperthermic rabbits

La farmacocinética sérica y tisular de cefepime administrado por vía endovenosa (20 mg/kg de peso) fue determinada en conejos sanos, con hipertermia producida por lipopolisacáridos de E. coli e implantados en tejido subcutáneo con cajas para recolección de líquido tisular. Diez conejos adultos fueron utilizados en dos experiencias (E1 y E2). Las concentraciones de cefepime en suero (S) y líquido tisular (LT) fueron determinadas por método biológico. Para el análisis cinético se utilizó un modelo no compartimental. Los resultados farmacocinéticos (medias ± error estándar) fueron: tiempo medio de eliminación [t1/2 (E1 S)=1,5±0,2 y (E2 S)=2,0±0,2 h] (p<0,05), área bajo la curva [ABC (E1 S)=181,6±17,5 y (E2 S)=192,3±18,5 (µg/mL/h]; Volumen de distribución en estado estacionario [Vss (E1S)=0,31±0,05 y (E2 S)=0,69±0,28 L/kg] (p<0,05); aclaramiento sérico [CL(E1 S)=118,3±17,7 y (E2 S) =93,1±19,9 (mL/h)kg] (p<0,05); Concentración máxima [Cmax (E1 LT)= 23,5±3,4 y (E2 LT)= 27,6±3,6 (µg/mL]; tiempo en el que se logra la Cmax [t max (E1 LT)=2,3±0,4 y (E2 LT)=1,7±0,4 h)]; t1/2 (E1 LT)= 2,4±0,3 y (E2 LT)=3,4±0,3 h (p<0,05); ABC (E1 LT)=122,0±12,7 y (E2 LT)=156,9±13,6 (µg/mL/h). y penetración [P (E1 LT)=67,3±8,7 y (E2 LT)=88,5±8,7%].

The pharmacokinetic characteristics in serum and tissue of cefepime given intravenously (20 mg/kg body weight) were assessed in healthy rabbits and in rabbits with hyperthermia induced by lipopolysacharide of E. coli, with tissue fluid cages implanted subcutaneously. Ten adult rabbits were used in two trials (E1 and E2). Cefepime concentrations in serum (S) and tissue cage fluid (LT) were determined by biological methods. The kinetic analysis was performed by means of a noncompartmental model. Pharmacokinetic results (means ± standard error): half life of elimination [t1/2 (E1 S)=1.5±0.2 and (E2 S)=2.0±0.2 h] (p<0.05), area under the curve [ABC (E1 S)=181.6±17.5 and (E2 S)= 192.3±18.5 (µg/mL/h]; volume of distribution at steady-state [Vss (E1 S)=0.31±0.05 and (E2 S)=0.69±0.28 L/kg] (p<0.05); total serum clearance [CL (E1 S)=118.3±17.7 and (E2 S)=93.1±19.9 (mL/h)kg] (p<0.05); maximum concentration [Cmax (E1 LT)=23.5±3.4 and (E2 LT)=27.6±3.6 (µg/mL]; time to reach Cmax [t max (E1 LT) =2.3±0.4 and (E2 LT)=1.7±0.4 h)]; t1/2 (E1 LT)=2.4±0.3 and (E2 LT)=3.4±0.3 h (p<0.05); ABC (E1 LT)=122.0±12.7 and (E2 LT)=156.9±13.6 (µg/mL/h); penetration [P (E1 LT)=67.3±8.7 and (E2 LT)=88.5±8.7%]. In conclusion, the pharmacokinetic changes of cefepime observed in rabbits with hyperthermia induced by lipopolysacharide, could be clinically significant if not taken into account when designing the dosing regimens.