The microbiota drives diurnal rhythms in tryptophan metabolism in the stressed gut.

Chronic stress disrupts microbiota-gut-brain axis function and is associated with altered tryptophan metabolism, impaired gut barrier function, and disrupted diurnal rhythms. However, little is known about the effects of acute stress on the gut and how it is influenced by diurnal physiology. Here, we used germ-free and antibiotic-depleted mice to understand how microbiota-dependent oscillations in tryptophan metabolism would alter gut barrier function at baseline and in response to an acute stressor. Cecal metabolomics identified tryptophan metabolism as most responsive to a 15-min acute stressor, while shotgun metagenomics revealed that most bacterial species exhibiting rhythmicity metabolize tryptophan. Our findings highlight that the gastrointestinal response to acute stress is dependent on the time of day and the microbiome, with a signature of stress-induced functional alterations in the ileum and altered tryptophan metabolism in the colon.

Prebiotic supplementation modulates selective effects of stress on behavior and brain metabolome in aged mice.

Aging has a significant impact on physiology with implications for central nervous system function coincident with increased vulnerability to stress exposures. A number of stress-sensitive molecular mechanisms are hypothesized to underpin age-related changes in brain function. Recent cumulative evidence also suggests that aging impacts gut microbiota composition. However, the impact of such effects on the ability of mammals to respond to stress in aging is still relatively unexplored. Therefore, in this study we assessed the ability of a microbiota-targeted intervention (the prebiotic FOS-Inulin) to alleviate age-related responses to stress. Exposure of aged C57BL/6 mice to social defeat led to an altered social interaction phenotype in the social interaction test, which was reversed by FOS-Inulin supplementation. Interestingly, this occured independent of affecting social defeat-induced elevations in the stress hormone corticosterone. Additionally, the behavioral modifications following FOS-Inulin supplementation were also not coincident with improvement of pro-inflammatory markers. Metabolomics analysis was performed and intriguingly, age associated metabolites were shown to be reduced in the prefrontal cortex of stressed aged mice and this deficit was recovered by FOS-Inulin supplementation. Taken together these results suggest that prebiotic dietary intervention rescued the behavioral response to stress in aged mice, not through amelioration of the inflammatory response, but by restoring the levels of key metabolites in the prefrontal cortex of aged animals. Therefore, dietary interventions could be a compelling avenue to improve the molecular and behavioral manifestations of chronic stress exposures in aging via targeting the microbiota-gut brain axis.

O papel da ressonância magnética na distinção das gestações intersticial, cornual e angular / The role of magnetic resonance imaging in distinguishing interstitial, cornual and angular pregnancies

Apesar da melhora no diagnóstico e tratamento, a gravidez ectópica ainda é a principal causa de mortalidade materna no primeiro trimestre da gravidez. Formas raras podem apresentar um desafio diagnóstico e, sem um diagnóstico adequado, a incidência de complicações e a mortalidade materna estão relacionadas a aumento de seus índices. Os termos "gravidez cornual" e "gravidez intersticial" têm sido utilizados de forma inconsistente na literatura, sendo frequentemente usados como sinônimos do termo "gravidez angular". Uma distinção estrita entre essas entidades pode ter implicações clínicas importantes, porque o curso natural, a propedêutica e os resultados diferem entre eles. A ressonância magnética não é o padrão-ouro para o diagnóstico de gravidez ectópica, no entanto possui relevância significativa no diagnóstico de possíveis complicações decorrentes dessa afecção. Nesse contexto, esta revisão aborda a importância da ressonância magnética na distinção dos tipos de gravidez mencionados, ilustrados por meio de casos do nosso serviço.(AU)

Despite the improvement in diagnostics and treatment, ectopic pregnancies are still the main cause of maternal mortality in the first trimester of pregnancy. Rare forms may present a diagnostic challenge and without adequate diagnosis, the incidence of complications and maternal mortality is greatly increased. The terms "cornual pregnancy" and "interstitial pregnancy" have been used inconsistently in the literature, frequently been used as synonyms and even used interchangeably with the term "angular pregnancy". A strict distinction among these entities can have important clinical implications because the natural course, management and outcomes differ among them. Magnetic resonance imaging is not the gold standard for the diagnosis of ectopic pregnancy, however, it can be useful in the diagnosis of complicated presentations of such ailment. In this context, this review highlights the importance of MRI in distinguishing the aforementioned types of pregnancies, illustrated with few cases from our service.(AU)