Gut Microbiota-Derived Tryptophan Metabolites Modulate Inflammatory Response in Hepatocytes and Macrophages.

The gut microbiota plays a significant role in the progression of fatty liver disease; however, the mediators and their mechanisms remain to be elucidated. Comparing metabolite profile differences between germ-free and conventionally raised mice against differences between mice fed a low- and high-fat diet (HFD), we identified tryptamine and indole-3-acetate (I3A) as metabolites that depend on the microbiota and are depleted under a HFD. Both metabolites reduced fatty-acid- and LPS-stimulated production of pro-inflammatory cytokines in macrophages and inhibited the migration of cells toward a chemokine, with I3A exhibiting greater potency. In hepatocytes, I3A attenuated inflammatory responses under lipid loading and reduced the expression of fatty acid synthase and sterol regulatory element-binding protein-1c. These effects were abrogated in the presence of an aryl-hydrocarbon receptor (AhR) antagonist, indicating that the effects are AhR dependent. Our results suggest that gut microbiota could influence inflammatory responses in the liver through metabolites engaging host receptors.

Differentiation of acute osteoporotic and malignant compression fractures of the spine: use of additive qualitative and quantitative axial diffusion-weighted MR imaging to conventional MR imaging at 3.0 T.

PURPOSE: To retrospectively determine the value of adding qualitative and quantitative axial diffusion-weighted (DW) imaging to standard spine magnetic resonance (MR) imaging to differentiate between acute osteoporotic and malignant compression fractures at 3.0 T. MATERIALS AND METHODS: The institutional ethics committee approved this retrospective study and waived the requirement to obtain informed consent. The authors retrospectively analyzed 3.0-T MR images, including DW images (b values: 0, 800, and 1400 sec/mm(2)), in 62 patients with acute compression fractures. Three radiologists independently interpreted MR images for the presence of malignancy by using conventional MR images alone and in combination with axial DW images with qualitative and quantitative analysis. Apparent diffusion coefficients (ADCs) were measured within solid portion with careful use of a small region of interest (ROI). The Mann-Whitney U test was performed. RESULTS: There were 30 malignant and 32 acute osteoporotic compression fractures. At qualitative analysis, hyperintensity relative to spinal cord was more frequent in malignant compression fractures than in acute osteoporotic compression fractures (87% vs 22%, respectively; P < .001). Median ADCs of malignant fractures were significantly lower than those of benign fractures (P < .001). With conventional MR imaging alone, sensitivity, specificity, and accuracy were 100%, 94%, and 97%, respectively, for reader 1; 97%, 78%, and 87% for reader 2; and 100%, 84%, and 92% for reader 3. With conventional and DW MR imaging combined, sensitivity, specificity, and accuracy were 100%, 97%, and 98% for all three readers. The addition of DW imaging led to correct changes in diagnosis: Reader 1 improved by 1.6% (one of 62 fractures), reader 2 improved by 11% (seven of 62 fractures), and reader 3 improved by 6.5% (four of 62 fractures). CONCLUSION: The addition of axial DW imaging to a conventional MR imaging protocol improved diagnostic accuracy in the differentiation of acute osteoporotic from malignant compression fractures by measuring ADCs in the solid portion with careful use of a small ROI.

Ventricular septal aneurysms in adults: findings of cardiac CT images and correlation with clinical features.

BACKGROUND: With the increasing use of multidetector computed tomography (MDCT), the number of incidentally detected ventricular septal aneurysms (VSAs) in adults has increased. However, to date, there are not sufficient well-organized data regarding VSAs in adults on MDCT. PURPOSE: To evaluate the CT findings of ventricular septal aneurysms (VSAs) in adults and correlate the findings with clinical features. MATERIAL AND METHODS: We performed a retrospective review of the cardiac CT reports in our electronic database of 3402 patients who underwent ECG-gated cardiac CT scans using a 64-slice multidetector CT or dual-source CT from October 2006 to December 2009 at our institute. Among them, eight patients were diagnosed with a VSA. We evaluated the location, size, and morphology of VSAs on cardiac CT angiographies (CCTAs) and correlated the findings with the clinical features of the patients. RESULTS: On CCTAs, all eight patients were found to have VSAs in the membranous portion of the interventricular septum and toward the right ventricle. The VSAs were 10-22 mm at their longest diameter and had wide necks. The VSAs were lobulated along the outer margin and were incidental findings in all patients. Four of the eight patients had a conduction abnormality such as first-degree atrio-ventricular block or incomplete right bundle branch block seen on ECG, whereas the other four patients had normal ECGs. CONCLUSION: VSA in adults is usually detected incidentally. It is seen in the membranous portion of the interventricular septum with a lobulated shape on CCTA. It is occasionally associated with a conduction anomaly.