Figure 1

Blood-brain barrier transport of human bioavailable (poly)phenol metabolites. (a) Schematic experimental design used to assess (poly)phenol metabolites transport across the BBB. (b) Endothelial transport of human bioavailable polyphenol metabolites after 2 h of incubation. Endothelial transport was evaluated by LC-Orbitrap MS and is presented as percentage (%) determined by the ratio of the lower compartment concentration and the sum of the upper and lower compartments concentrations. Statistical differences for p < 0.01 are denoted from a-f. (c–e) Immunofluorescence detection of major efflux transporters in HBMEC line: (c) P-gp, in green, (d) MRP1, in red and (e) BCRP, in green. Nuclei stained with DAPI (blue). Scale bar: 40 µm. (f–h) HBMEC intracellular accumulation of specific efflux transporters’ substrates in the presence of the respective inhibitors: (f) 1 µM of verapamil (P-gp inhibitor), (g) 1 µM MK-571 (MRP1 inhibitor) or (h) 1 µM of Ko 143 (BCRP inhibitor). Statistical differences are denoted as ***p < 0.001, **p < 0.01 and *p < 0.05 relatively to control cells. Endothelial transport of (i) Cat-sulf and (j) Pyr-sulf when co-incubated with efflux transporters inhibitors. Statistical differences in the presence of inhibitors are denoted as *p < 0.05 relatively to “No inhibitor”. (k) P-gp substrate accumulation for Cat-sulf and Pyr-sulf compared with verapamil. Intracellular accumulation of P-gp substrate, Rhodamine 123 was evaluated after pre-incubation of cells with the bioavailable (poly)phenol metabolites. Statistical differences are denoted as ***p < 0.001 relatively to control. (l) Endothelial transport of Cat-sulf (solid line) and Pyr-sulf (dashed line) along time. Statistical differences along time are denoted as ***p < 0.001, relatively to 2 h of incubation in Cat-sulf, or ^###p < 0.001, relatively to 2 h of incubation in Pyr-sulf. All values are means ± SD, n=3.