[Molecular characterization of Listeria monocytogenes isolates from human and food sources in Argentina, 2018-2023]. / Caracterización molecular de aislamientos de Listeria monocytogenes de origen humano y alimentario en Argentina, 2018-2023.

Human listeriosis is an infectious disease caused by Listeria monocytogenes. The invasive form of this disease leads to a high rate of hospitalizations and fatality. The main mode of transmission is through contaminated ready-to-eat foods such as dairy, vegetables and meat products. The knowledge of the diversity and population dynamics of isolates collected from human and food sources is essential for the detection of clusters and the identification of common sites of infection. The aim of this study was the molecular characterization of L. monocytogenes isolates in Argentina. We sequenced a total of 63 isolates, 35 from human and 28 from food sources, collected between 2018 and 2023. Our genomic study divided the isolates into two lineages, four serogroups, 17 sequence types and 15 clonal complexes (CCs). The hypervirulent clone CC1 (lineage I; serogroup IVb) predominated in human and food samples. The phylogenomic analysis showed a high and possible epidemiological relationship between isolates from human and/or food sources, suggesting the presence of transmission chains in our country. These findings highlight the need to strengthen genomic surveillance of L. monocytogenes in Argentina. The identification of geographic distribution and characteristics of predominant and emerging clones from human and food sources might help to focus action plans and public health policies better directed at the control and prevention of listeriosis.

First molecular characterization of Escherichia coli O157:H7 isolates from clinical samples in Paraguay using whole-genome sequencing.

Escherichia coli O157:H7 is a foodborne pathogen implicated in numerous outbreaks worldwide that has the ability to cause extra-intestinal complications in humans. The Enteropathogens Division of the Central Public Health Laboratory (CPHL) in Paraguay is working to improve the genomic characterization of Shiga toxin-producing E. coli (STEC) to enhance laboratory-based surveillance and investigation of foodborne disease outbreaks. Whole genome sequencing (WGS) is proposed worldwide to be used in the routine laboratory as a high-resolution tool that allows to have all the results in a single workflow. This study aimed to carry out for the first time, the genomic characterization by WGS of nine STEC O157:H7 strains isolated from human samples in Paraguay. We were able to identify virulence and resistance mechanisms, MLST subtype, and even establish the phylogenetic relationships between isolates. Furthermore, we detected the presence of strains belonging to hypervirulent clade 8 in most of the isolates studied.

Bayesian network analysis of plasma microRNA sequencing data in patients with venous thrombosis.

MicroRNAs (miRNAs) are small regulatory RNAs participating to several biological processes and known to be involved in various pathologies. Measurable in body fluids, miRNAs have been proposed to serve as efficient biomarkers for diseases and/or associated traits. Here, we performed a next-generation-sequencing based profiling of plasma miRNAs in 344 patients with venous thrombosis (VT) and assessed the association of plasma miRNA levels with several haemostatic traits and the risk of VT recurrence. Among the most significant findings, we detected an association between hsa-miR-199b-3p and haematocrit levels (P = 0.0016), these two markers having both been independently reported to associate with VT risk. We also observed suggestive evidence for association of hsa-miR-370-3p (P = 0.019), hsa-miR-27b-3p (P = 0.016) and hsa-miR-222-3p (P = 0.049) with VT recurrence, the observations at the latter two miRNAs confirming the recent findings of Wang et al. Besides, by conducting Genome-Wide Association Studies on miRNA levels and meta-analyzing our results with some publicly available, we identified 21 new associations of single nucleotide polymorphisms with plasma miRNA levels at the statistical significance threshold of P < 5 × 10-8, some of these associations pertaining to thrombosis associated mechanisms. In conclusion, this study provides novel data about the impact of miRNAs' variability in haemostasis and new arguments supporting the association of few miRNAs with the risk of recurrence in patients with venous thrombosis.

Los micro-ARN (miARN) son pequeñas moléculas de ARN reguladoras que participan en varios procesos biológicos y están implicados en diversas patologías. Mensurables en los líquidos corporales, se ha planteado que los miARN pueden ser biomarcadores eficaces para el diagnóstico de enfermedades y/o características asociadas. Aquí hemos llevado a cabo un análisis de miARN plasmático con tecnología de secuenciación de última generación en 344 pacientes con trombosis venosa (TV) y hemos evaluado la asociación de los niveles de miARN con distintas características hemostáticas y el riesgo de recidiva de TV. Entre los hallazgos más significativos, hemos detectado una asociación entre hsa-miR-199b-3p y los niveles de hematocritos (p = 0,0016); dos marcadores que se habían asociado de forma independiente con el riesgo de sufrir TV. Asimismo, hemos observado una evidencia indicativa de asociación entre hsa-miR-370-3p (p = 0,019), hsa-miR-27b-3p (p = 0,016) y hsa-miR-222-3p (p = 0,049) y la recidiva de TV; los resultados los dos últimos miARN confirman los hallazgos recientes de Wang et al. (Clin Epigenetics, 2019). Además, al efectuar estudios de asociación del genoma completo sobre los niveles de miARN y al metaanalizar nuestros resultados con otros disponibles públicamente, hemos identificado 21 asociaciones nuevas de polimorfismos de un solo nucleótido (PSN) con niveles de miARN plasmático con un umbral de significación estadística de p < 5 × 10−8; algunas de estas asociaciones pertenecen a los mecanismos patogénicos de la trombosis.Como conclusión, en este estudio se proporcionan nuevos datos sobre el impacto de la variabilidad de miARN en la hemostasia y nuevos argumentos que apoyan la asociación de algunas secuencias de miARN con el riesgo de recidiva en pacientes con trombosis venosa.

[Genetic predisposition and Pediatric Acute Respiratory Distress Syndrome: New tools for genetic study]. / Predisposición genética y síndrome de distrés respiratorio agudo pediátrico: nuevas herramientas de estudio genético.

Acute respiratory distress syndrome (ARDS) is the most severe form of respiratory failure. Theoretically, any acute lung condition can lead to ARDS, but only a small percentage of individuals actually develop the disease. On this basis, genetic factors have been implicated in the risk of developing ARDS. Based on the pathophysiology of this disease, many candidate genes have been evaluated as potential modifiers in patient, as well as in animal models, of ARDS. Recent experimental data and clinical studies suggest that variations of genes involved in key processes of tissue, cellular and molecular lung damage may influence susceptibility and prognosis of ARDS. However, the pathogenesis of pediatric ARDS is complex, and therefore, it can be expected that many genes might contribute. Genetic variations such as single nucleotide polymorphisms and copy-number variations are likely associated with susceptibility to ARDS in children with primary lung injury. Genome-wide association (GWA) studies can objectively examine these variations, and help identify important new genes and pathogenetic pathways for future analysis. This approach might also have diagnostic and therapeutic implications, such as predicting patient risk or developing a personalized therapeutic approach to this serious syndrome.

Epidemiological changes in invasive Streptococcus pyogenes infection during the UK alert period: A molecular comparative analysis from a tertiary Spanish hospital in 2023.

OBJECTIVES: To study the genomic epidemiology of Streptococcus pyogenes causing bloodstream infections (GAS-BSI) in a Spanish tertiary hospital during the United Kingdom invasive S. pyogenes outbreak alert. METHODS: Retrospective epidemiological analysis of GAS-BSI during the January-May 2017-2023 period. WGS was performed using Ion torrent GeneStudio™ S5 system for emm typing and identification of superantigen genes in S. pyogenes isolated during the 2022-2023 UK outbreak alert. RESULTS: During 2023, there were more cases of GAS-BSI compared to the same period of previous year with a non-significant increase in children. Fourteen isolates were sequenced. The emm1 (6/14, 42.9%) and emm12 (2/14, 14.3%) types predominated; 5 of 6 (75%) emm1 isolates were from the M1UK clone. The most detected superantigen genes were speG (12/14, 85.7%), speC (10/14, 71.4%), speJ (7/14, 50%), and speA (5/15, 33.3%). speA and speJ were predominant in M1UK clone. CONCLUSIONS: Our genomic epidemiology in 2023 is similar to the reported data from the UK outbreak alert in the same period and different from previous national S. pyogenes surveillance reports.

Population structure of Neisseria meningitidis ST-9493 identified in Colombian isolates.

INTRODUCTION: Neisseria meningitidis is associated with invasive infections causing high mortality rates. The objective of this study was to describe the population structure of Colombian invasive isolates with ST-9493, a potentially emerging clonal group in the country. METHODS: The complete genomes of 34 invasive isolates of serogroup B with ST-9493 and its variants at one or two loci were sequenced by Illumina to describe the phenotypic and genotypic characteristics of these isolates. RESULTS: The relationship of a clonal group associated with ST-136 CC41/44 was phylogenetically established, identifying two main clades composed of isolates from an outbreak or endemic. The most frequent alleles and peptides included porA 17, porB 44, fHbp 2.24, NHBA 10, and the FetA F5-17 variant. Most of the isolates were susceptible to the antibiotics evaluated. CONCLUSION: This study shows that meningococcal isolates with ST-9493 are an autochthonous clonal group with population dynamics and the capacity to cause endemic and epidemic meningococcal disease in Colombia.

The Future of TB Resistance Diagnosis: The Essentials on Whole Genome Sequencing and Rapid Testing Methods.

Tuberculosis resistance diagnostics have vastly improved in recent years thanks to the development of standardised phenotypic and molecular testing methods. However, these methods are either slow or limited in the number of resistant genotypes they can detect. With the advent of next-generation sequencing (NGS) we can sidestep all those problems, as we can sequence whole tuberculosis genomes at increasingly smaller costs and requiring less and less DNA. In this review, we explain how accumulated knowledge in the field has allowed us to go from phenotypic testing to molecular methods to Whole Genome Sequencing (WGS) for resistance diagnostics. We compare current diagnostic methods with WGS as to their efficacy in detecting resistant cases, and show how forthcoming advances in NGS technologies will be crucial in widespread implementation of WGS as a diagnostic tool.

Vitamin D-associated genetic variants in the Brazilian population: Investigating potential instruments for Mendelian randomization / Variantes genéticas asociadas con la vitamina D en la población brasileña: investigación de potenciales instrumentos para aleatorización mendeliana

Introduction. Vitamin D is required for bone and mineral metabolism and participates in the regulation of the immune response. It is also linked to several chronic diseases and conditions, usually in populations of European descent. Brazil presents a high prevalence of vitamin D deficiency and insufficiency despite the widespread availability of sunlight in the country. Thus, it is important to investigate the role of vitamin D as a risk factor for disease and to establish causal relationships between vitamin D levels and health-related outcomes in the Brazilian population. Objective. To examine genetic variants identified as determinants of serum vitamin D in genome-wide association studies of European populations and check whether the same associations are present in Brazil. If so, these single nucleotide polymorphisms (SNPs) could be developed locally as proxies to use in genetically informed causal inference methods, such as Mendelian randomization. Materials and methods. We extracted SNPs associated with vitamin D from the genome-wide association studies catalog. We did a literature search to select papers ascertaining these variants and vitamin D concentrations in Brazil. Results. GC was the gene with the strongest association with vitamin D levels, in agreement with existing findings in European populations. However, VDR was the most investigated gene, regardless of its non-existing association with vitamin D in the genomewide association studies. Conclusions. More research is needed to validate sound proxies for vitamin D levels in Brazil, for example, prioritizing GC rather than VDR.

Introducción. La vitamina D es necesaria para el metabolismo óseo y mineral, y participa en la regulación de la respuesta inmunitaria. También está relacionada con enfermedades crónicas en poblaciones europeas. En Brasil, existe una prevalencia elevada de deficiencia e insuficiencia de vitamina D, a pesar de la amplia disponibilidad de luz solar. Por lo tanto, es importante investigar el papel de la vitamina D como factor de riesgo de diversas enfermedades y establecer relaciones causales entre los niveles de vitamina D y los problemas de salud en la población brasileña. Objetivo. Examinar variantes genéticas relacionadas con la vitamina D sérica en estudios de asociación genómica de poblaciones europeas y comprobar si estas mismas están presentes en Brasil. De ser así, estos SNPs podrían utilizarse como proxies en métodos de inferencia causal, tales como la aleatorización mendeliana. Materiales y métodos. A partir del catálogo de estudios de asociación de genoma completo se extrajeron SNPs relacionados con los niveles de vitamina D. Luego se hizo una búsqueda bibliográfica para identificar los artículos que evaluaran estos SNPs y la concentración de vitamina D en Brasil. Resultados. GC fue el gen más fuertemente asociado con los niveles de vitamina D, en concordancia con los resultados existentes en poblaciones europeas. Sin embargo, el gen VDR fue el más investigado, aunque no esté vinculado con la vitamina D en los estudios de asociación de genoma completo. Conclusiones. Se necesita más investigación para validar proxies genéticos de los niveles de vitamina D en Brasil y se recomienda priorizar el gen GC en lugar de VDR.

First molecular characterization of Escherichia coli O157:H7 isolates from clinical samples in Paraguay using whole-genome sequencing Molecular characterization of Escherichia coli O157 isolates from Paraguay / Primera caracterización molecular de aislamientos de Escherichia coli O157:H7 provenientes de muestras clínicas en Paraguay utilizando secuenciación de genoma completo

Abstract Escherichia coli O157:H7 is a foodborne pathogen implicated in numerous outbreaks worldwide that has the ability to cause extra-intestinal complications in humans. The Enteropathogens Division of the Central Public Health Laboratory (CPHL) in Paraguay is working to improve the genomic characterization of Shiga toxin-producing E. coli (STEC) to enhance laboratory-based surveillance and investigation of foodborne disease outbreaks. Whole genome sequencing (WGS) is proposed worldwide to be used in the routine laboratory as a high-resolution tool that allows to have all the results in a single workflow. This study aimed to carry out for the first time, the genomic characterization by WGS of nine STEC O157:H7 strains isolated from human samples in Paraguay. We were able to identify virulence and resistance mechanisms, MLST subtype, and even establish the phylogenetic relationships between isolates. Furthermore, we detected the presence of strains belonging to hypervirulent clade 8 in most of the isolates studied.

Resumen Escherichia coli O157:H7 es un patógeno transmitido por alimentos implicado en numerosos brotes en todo el mundo y es capaz de causar complicaciones extraintestinales en humanos. La sección de «Enteropatógenos¼ del Laboratorio Central de Salud Pública trabaja en mejorar la caracterización genómica de STEC, de modo de potenciar la vigilancia laboratorial y la investigación de brotes de enfermedades transmitidas por alimentos. La secuenciación de genoma completo (WGS, por sus siglas en inglés) se propone a nivel mundial como una herramienta de alta resolución para ser utilizada en el laboratorio de rutina, ya que permite obtener todos los resultados en un único proceso. El objetivo de este trabajo fue llevar a cabo, por primera vez, la caracterización genómica por WGS de nueve cepas STEC O157:H7 aisladas en Paraguay a partir de muestras de origen humano. Pudimos identificar los factores de virulencia, los mecanismos de resistencia, el subtipo MLST, e incluso pudimos establecer la relación filogenética entre los aislamientos. Además, detectamos que la mayoría de las cepas pertenecían al clado hipervirulento 8.

Estructura, propiedades y genética de las caseínas de la leche: una revisión / Structure, properties and genetic of milk caseins: a review / Estrutura, propriedades e genética das caseínas do leite: uma revisão

Resumen La leche es un alimento esencial para los humanos y una de sus importancias radica en el contenido de proteínas lácteas. Las proteínas más frecuentes en este preciado líquido son las caseínas (αS1-caseína, αS2-caseína, β-caseína y κ-caseína), las cuales son fuente de aminoácidos para la dieta de los mamíferos en sus primeros días de vida. En la leche, las caseínas, están formadas por agregados moleculares de proteínas de tamaños variables denominados micelas. El objetivo de esta revisión es presentar un panorama general de la estructura, propiedades y genética de las caseínas lácteas y su relación con la salud humana. A partir de esta revisión, se pudo establecer, que las αs1 y αs2 caseínas se encuentran en conjunto con la β-caseína, formando el núcleo micelar, interactuando con los iones de calcio, para formar y mantener la micela estable. Animales caracterizados genéticamente con algunas variantes de estas proteínas, se asocian con un rendimiento en el volumen de leche. La κ-caseína, por su parte, está asociada con un aumento en el rendimiento y calidad de los quesos, de ahí su importancia económica, mientras que las formas más comunes de β-caseína en razas de ganado lechero son A1 y A2. La β-caseína A2 no presenta efectos negativos a la salud humana, por el contrario, ha sido asociada con propiedades reductoras de colesterol y triacilglicéridos. Sin embargo, la variante A1 de la β-caseína produce un péptido bioactivo denominado β-casomorfina-7 (BCM-7), que puede desempeñar un papel etiológico poco claro en el desarrollo de algunas enfermedades en humanos, tales como: enfermedad isquémica del corazón, diabetes mellitus tipo 1, síndrome de muerte súbita infantil (SIDS), desórdenes neurológicos, como autismo y esquizofrenia.

Abstract Milk is an essential food for humans and one of the reasons of its importance lies in the content of milk proteins. The most frequent proteins in this precious liquid are caseins (αS1-casein, αS2-casein, β-casein and κ-casein), which are a source of amino acids for the diet of mammals in their first days of life. In milk, caseins are made up of molecular aggregates of proteins of varying sizes called micelles. The objective of this review is to present an overview of the structure, properties and genetics of dairy caseins and their relation with human health. From this review, it was established that αs1 and αs2 caseins are found together with β-casein, forming the micellar nucleus and interacting with calcium ions, to form and maintain stable the micelle. Animals genetically characterized with some variants of these proteins are associated with a yield in milk volume. For its part, κ-casein is associated with an increase in the yield and quality of cheeses, hence its economic importance, while the most common forms of β-casein in dairy cattle are A1 and A2. β-casein A2 does not have negative effects on human health; on the contrary, it has been associated with lowering properties of cholesterol and triacylglycerides. However, the A1 variant of β-casein produces a bioactive peptide called β-casomorphin-7 (BCM-7), which may play an unclear etiological role in the development of some diseases in humans, such as: ischemic heart disease, type 1 diabetes mellitus, sudden infant death syndrome (SIDS), neurological disorders, such as autism and schizophrenia.

Resumo O leite é um alimento essencial para o ser humano e uma de suas principais característica é o teor de proteínas do leite. As proteínas mais frequentes neste líquido são as caseínas (αS1-caseína, αS2-caseína, β-caseína e κ-caseína), que são uma fonte de aminoácidos para a dieta dos mamíferos nos primeiros dias de vida. As caseínas no leite são constituídas por agregados moleculares de proteínas de variados tamanhos, chamados micelas. O objetivo desta revisão é apresentar uma visão geral da estrutura, propriedades e genética das caseínas lácteas e sua relação com a saúde humana. A partir desta revisão, foi estabelecido que as caseínas αs1 e αs2 são encontradas em conjunto com a β-caseína, formando o núcleo micelar, interagindo com os íons cálcio, para formar e manter a micela estável. Animais geneticamente caracterizados com algumas variantes dessas proteínas estão associados com o rendimento da produção de leite. Por sua vez, a κ-caseína está associada ao aumento do rendimento da produção e da qualidade dos queijos, por isso sua importância econômica, enquanto as formas mais comuns de β-caseína em bovinos leiteiros são A1 e A2. A Β-caseína A2 não tem efeitos negativos na saúde humana, pelo contrário, tem sido associada a propriedades redutoras do colesterol e dos triacilglicéridos. No entanto, a variante A1 da β-caseína produz um peptídeo bioativo denominado β-casomorfina-7 (BCM-7), que pode desempenhar uma função etiológico ainda desconhecida no desenvolvimento de algumas doenças em humanos, tais como: doença isquêmica do coração, diabetes mellitus tipo 1, síndrome da morte súbita infantil (SMSL), distúrbios neurológicos, como autismo e esquizofrenia.

Genetics of osteoarthritis.

Osteoarthritis (OA) is a complex disease caused by the interaction of multiple genetic and environmental factors. This review focuses on the studies that have contributed to the discovery of genetic susceptibility factors in OA. The most relevant associations discovered until now are discussed in detail: GDF-5, 7q22 locus, MCF2L, DOT1L, NCOA3 and also some important findings from the arcOGEN study. Moreover, the different approaches that can be used to minimize the specific problems of the study of OA genetics are discussed. These include the study of microsatellites, phenotype standardization and other methods such as meta-analysis of GWAS and gene-based analysis. It is expected that these new approaches contribute to finding new susceptibility genetic factors for OA.

[Update on the genetics of stroke]. / Actualización en la genética del ictus.

Stroke is a disease with significant morbidity, mortality, and economic and social impacts. It is a complex entity whose pathogenesis involves multiple environmental and genetic factors, with the latter having a role in up to 50% of strokes. The objective of the review is to analyze the available methods for the genetic diagnosis including linkage studies of variation in copy number, gene - candidate approximations, or whole genome (GWAS) and polymorphisms associated with its pathogenesis. We describe several single nucleotide polymorphisms (SNPs) associated with stroke in association studies and GWAS such as SNPs of angiotensin, the aldosterone system, paraoxonases, nitric oxide, coagulation, and fibrinolysis system, among others. We also analyze the role of certain polymorphisms in the phenotype of the carotid plaque, intracranial aneurysms and lobar hemorrhages. Pharmacogenomic aspects in which SNPs affect the response and safety regarding the use of different drugs are also described. Several SNPs that significantly contribute to the risk of stroke are also described. The advent of techniques like GWAS has contributed to the understanding of genetics and pharmacogenomics of stroke.

Predisposición genética y síndrome de distrés respiratorio agudo pediátrico: nuevas herramientas de estudio genético / Genetic predisposition and Pediatric Acute Respiratory Distress Syndrome: New tools for genetic study

El síndrome de distrés respiratorio agudo (SDRA) es la forma más grave de falla respiratoria. Teóricamente, cualquier noxa pulmonar aguda puede resultar en un SDRA, pero solo un pequeño porcentaje de individuos desarrolla la enfermedad. Sobre este fundamento, factores genéticos han sido implicados en el riesgo de desarrollar SDRA. Basado en la fisiopatología de esta enfermedad, múltiples genes candidatos han sido evaluados como potenciales modificadores, tanto en pacientes como en modelos animales de SDRA. Datos experimentales y estudios clínicos recientes sugieren que variantes de genes implicados en procesos clave de daño tisular, celular y molecular pulmonar pueden influir en la predisposición y el pronóstico del SDRA. Sin embargo, la patogénesis del SDRA pediátrico es compleja y, en consecuencia, es posible anticipar que muchos genes pueden contribuir a ella. Variantes genéticas, tales como polimorfismos de nucleótido simple y variantes del número de copias, están probablemente asociadas con la predisposición al SDRA en niños con lesión pulmonar primaria. El estudio de asociación del genoma completo (GWAS, del inglés Genome-Wide Association Study) puede examinar estas variantes sin sesgos y ayudar a identificar nuevos genes fundamentales y vías patogénicas clave para futuros análisis. Esta aproximación también puede tener implicancias clínicas diagnósticas y terapéuticas, como predecir el riesgo del paciente o desarrollar un enfoque terapéutico personalizado para este grave síndrome.

Acute respiratory distress syndrome (ARDS) is the most severe form of respiratory failure. Theoretically, any acute lung condition can lead to ARDS, but only a small percentage of individuals actually develop the disease. On this basis, genetic factors have been implicated in the risk of developing ARDS. Based on the pathophysiology of this disease, many candidate genes have been evaluated as potential modifiers in patient, as well as in animal models, of ARDS. Recent experimental data and clinical studies suggest that variations of genes involved in key processes of tissue, cellular and molecular lung damage may influence susceptibility and prognosis of ARDS. However, the pathogenesis of pediatric ARDS is complex, and therefore, it can be expected that many genes might contribute. Genetic variations such as single nucleotide polymorphisms and copy-number variations are likely associated with susceptibility to ARDS in children with primary lung injury. Genome-wide association (GWA) studies can objectively examine these variations, and help identify important new genes and pathogenetic pathways for future analysis. This approach might also have diagnostic and therapeutic implications, such as predicting patient risk or developing a personalized therapeutic approach to this serious syndrome.

Impacto do tempo de isquemia na análise de expressão gênica global em tecidos criopreservados / Impact of cold ischemia on global gene expression in cryopreserved tissues

O perfil de expressão gênica tem passado do cenário da pesquisa básica para a prática clínica, sendo cada vez mais utilizado como ferramenta na classificação de subtipos moleculares do câncer. No entanto, deve-se ter cautela ao interpretar as assinaturas gênicas, uma vez que os métodos de manuseio e preservação da amostra podem afetar a expressão gênica. "Isquemia fria", quando aplicada à coleta e preservação de tecidos para pesquisa, refere-se ao período transcorrido desde a retirada do órgão do corpo e coleta da amostra, até o momento do seu congelamento em nitrogênio líquido. O objetivo geral deste trabalho foi avaliar o impacto do tempo de isquemia fria na expressão gênica global pela técnica de microarray em um modelo animal. Avaliamos 3 órgãos (pulmão, fígado e rim) de 52 camundongos (Mus musculus C57Bl/6), gerando 312 tecidos submetidos a diferentes tempos de isquemia (zero ou referência, 15, 30, 45 e 60 minutos). A expressão gênica global foi avaliada na plataforma SurePrint G3 Mouse GE 8x60K Microarray, que cobre o genoma completo do camundongo. Como resultado deste trabalho, os RNA totais extraídos tiveram alta qualidade (RIN médio de 9,4) e observamos alterações em genes que podem ser atribuídas ao processo isquêmico per se (p<0.05 e fold-change |2|). Alguns desses genes são conhecidamente relacionados ao câncer: fatores de transcrição (Fos, Hif3A), oncogenes (Ret, Srsf3), supressores tumorais (Btg1, Hnf1a), genes envolvidos no reparo do DNA, diferenciação e atividades de quinase. Esses genes devem ser olhados com cautela nas assinaturas genômicas para um desempenho analítico mais confiável. Foram encontradas variações de expressão gênica relacionadas a processos de controle de íons intracelulares e controle do pH. Evidenciou-se a importância da criopreservação imediata do tecido, ou, pelo menos, o mais rápido possível após a coleta, visando minimizar os efeitos de variação da expressão gênica decorrentes da isquemia (AU)

Gene expression profile has been moved from basic research to clinical practice, and it is increasingly being used as a tool in the classification of molecular subtypes in cancer. However, caution should be exercised when interpreting gene signatures, as sample handling and preservation methods may affect gene expression. "Cold ischemia", when applied to tissue collection and preservation for research, refers to the period from organ removal from the body and sample collection until it is frozen in liquid nitrogen. The general objective of this work was to evaluate the impact of cold ischemia time on global gene expression by microarray technique in an animal model. We evaluated 3 organs (lung, liver and kidney) from 52 mice (Mus musculus C57Bl / 6), generating 312 tissues submitted to different ischemia times (zero or reference, 15, 30, 45 and 60 minutes). Global gene expression was evaluated on the SurePrint G3 Mouse GE 8x60K Microarray platform that covers the complete mouse genome. As a result of this work, the extracted total RNAs had high quality (mean RIN of 9.4) and we evidenced changes in genes that can be attributed to the ischemic process per se (p <0.05 and fold-change | 2 |). Some of these genes are known to be related to cancer: transcription factors (Fos, Hif3A), oncogenes (Ret, Srsf3), tumor suppressors (Btg1, Hnf1a), genes involved in DNA repair, differentiation and kinase activities. These genes should be viewed with caution in genomic signatures for more reliable analytical performance. Gene expression variations related to intracellular ion control and pH control processes were observed. The importance of immediate tissue cryopreservation, or at least as soon as possible after collection, was evidenced in order to minimize the effects of gene expression variation resulting from ischemia (AU)