Fig. 3.

GVB leakage allows the passage of large molecules and bacteria. (A–F) Mice were fed with control (Ctrl) diet or HFD for 1 week, and (A) liver sections were submitted to eubacteria (green) and non-eub (red) FISH, before CD45 (white) and DAPI (blue) staining. Side images show merged and individual staining of enlarged areas demarcated by squares in the main picture, scale bar indicates 10 µm. (B) Bacteria were enumerated for each mouse, and percentage of bacteria inside or outside CD45⁺ cells was determined. (C) LPS levels were measured in the serum of 1-week HFD-fed mice. (D–F) One-week-fed mice were injected i.v. with 500 kDa FITC-dextran and imaged by intravital probe-based confocal microscopy. Representative photograms from the endomicroscopy video at indicated time points are shown in C, scale bar indicates 20 µm. Quantification of the fluorescence was measured as described in materials and methods. (E) The fluorescence ratio was plotted over time and (F) the AUC was calculated for each individual mouse. Fecal microbiota transplant of 1-week-fed donors was performed according to the schema in G and as described in materials and methods. Recipients were analyzed 1 week later. (H) Organ and body weight were determined and EAT weight (% of body) was calculated. (I) Cecum was stained for PV1 (red), CD34 (green) and DAPI (blue), scale bar indicates 50 µm. Quantification of PV1 was performed on CD34⁺ area (j). *p <0.05; **p <0.005; ***p <0.0005; ****p <0.0001 unpaired 2-tailed t test. AUC, area under the curve; EAT, epididymal adipose tissue; FISH, fluorescence in situ hybridization; GVB, gut vascular barrier; HFD, high-fat diet; LPS, lipopolysaccharide; MFI, mean fluorescence intensity.