Análise da microbiota intestinal em adultos com hábitos alimentares distintos e de associações com a inflamação e resistência à insulina / Gut microbiota analysis of adults with distinct dietary habits and associations with inflammation and insulin resistance

Introdução: A microbiota intestinal possui grande diversidade de bactérias, predominantemente dos filos Bacteroidetes e Firmicutes, com múltiplas funções. A alimentação pode alterar sua composição e função. Alto teor de gordura saturada altera a permeabilidade intestinal, eleva os lipopolissacarídeos e predispõe à inflamação subclínica crônica. Dieta rica em fibras, como a vegetariana, induz elevação de ácidos graxos de cadeia curta e benefícios metabólicos. Objetivos: Para analisar a composição da microbiota intestinal de adventistas com diferentes hábitos alimentares e associá-los à inflamação subclínica e resistência à insulina, esta tese incluiu: 1) revisão dos mecanismos que associam a alimentação à microbiota intestinal e ao risco cardiometabólico; 2) verificação da composição da microbiota intestinal segundo diferentes hábitos alimentares e de associações com biomarcadores de doenças cardiometabólicas; 3) avaliação da associação entre a abundância de Akkermansia muciniphila e o metabolismo da glicose; 4) análise da presença de enterótipos e de associações com características clínicas. Métodos: Este estudo transversal incluiu 295 adventistas estratificados segundo hábitos alimentares (vegetariano estrito, ovo-lacto-vegetariano e onívoro). Foram avaliadas associações com dados clínicos, bioquímicos e inflamatórios. O perfil da microbiota foi obtido por sequenciamento do gene 16S rRNA

Introduction: The gut microbiota has great bacterial diversity, predominantly of the phyla Bacteroidetes and Firmicutes, with multiple functions. Diet can alter their composition and function. High amount of saturated fat alters intestinal permeability, raises the lipopolysaccharides and predisposes to low-grade inflammation. High-fiber diet, such as the vegetarian, induces the elevation of short-chain fatty acids and metabolic benefits. Objectives: To analyze the composition of gut microbiota of Adventists with diverse dietary patterns and associate them to the low grade inflammation and insulin resistance this thesis included: 1) review of underlying mechanisms of the association of diet, gut microbiota composition and cardiometabolic risk; 2) analysis of the gut microbiota composition according to different dietary patterns and associations with biomarkers of cardiometabolic diseases; 3) evaluation of the association between the Akkermansia muciniphila abundance and glucose metabolism; 4) analysis of the presence of enterotypes and associations with clinical characteristics. Methods: This cross-sectional study included 295 Adventists stratified according to dietary patterns (strict vegetarian, lacto-ovo-vegetarian and omnivore). Their associations with clinical, biochemical and inflammatory data were evaluated. The microbiota profile was obtained by sequencing 16S rRNA genes

Evolutionary and Ecological Characterization of Mayaro Virus Strains Isolated during an Outbreak, Venezuela, 2010.

In 2010, an outbreak of febrile illness with arthralgic manifestations was detected at La Estación village, Portuguesa State, Venezuela. The etiologic agent was determined to be Mayaro virus (MAYV), a reemerging South American alphavirus. A total of 77 cases was reported and 19 were confirmed as seropositive. MAYV was isolated from acute-phase serum samples from 6 symptomatic patients. We sequenced 27 complete genomes representing the full spectrum of MAYV genetic diversity, which facilitated detection of a new genotype, designated N. Phylogenetic analysis of genomic sequences indicated that etiologic strains from Venezuela belong to genotype D. Results indicate that MAYV is highly conserved genetically, showing ≈17% nucleotide divergence across all 3 genotypes and 4% among genotype D strains in the most variable genes. Coalescent analyses suggested genotypes D and L diverged ≈150 years ago and genotype diverged N ≈250 years ago. This virus commonly infects persons residing near enzootic transmission foci because of anthropogenic incursions.