(A) Flow cytometry analysis of CD9 (green) and intercellular adhesion molecule (ICAM)-3 (orange) expression in resting and tumor necrosis factor-–activated human umbilical vein endothelial cells (HUVECs). Inducible ICAM-1 expression (blue) was used as positive control of tumor necrosis factor-–induced HUVEC activation, and X-63 (red) was used as negative control. (B) Time course of attachment of Targestar^B microbubbles under flow conditions. Noncoupled biotinylated microbubbles (naked Targestar^B, green), microbubbles coupled to anti-CD9 (blue), or to an isotype-matched ICAM-3 control antibody (red) were perfused at increasing flow rates over fibronectin, resting or activated HUVEC monolayers. Microbubble attachment to each substrate was quantified over time and represented in 2 different types of histograms (cumulative or noncumulative binding events). (C) Representative images of control versus anti–CD9-coupled microbubbles attached to resting HUVEC monolayers during the post-treatment washout period. Boxed areas are shown at high magnification in the lower panels. Microbubbles attached to the endothelial monolayers are marked with a red outline; those out of the focal plane were considered as not interacting with the endothelium. Screen area = 0.06 mm². TNF = tumor necrosis factor.

(A) Representative echographic images of the long and short axes of human umbilical cords perfused with naked, control antibody-, or anti–CD9-coupled Targestar^B microbubbles. Images are of umbilical cords maintained under resting or tumor necrosis factor- inflammatory conditions. Dashed yellow lines delineate the luminal area to distinguish the MB attached to endothelium from free-flowing ones. (B) Representative isosurface plots of negative (left) and positive (right) targeting images from long (top) and short axes (bottom). (C) In the box and whisker plots, the box extends from the 25th percentile to the 75th percentile, with a line at the median (the 50th percentile). The whiskers extend above and below the box to show the highest and lowest values of contrast-enhanced ultrasound video intensity measured in echographic images from every treatment (n ranging from 10 to 18). Statistical analysis was performed with a Kruskal-Wallis test (p < 0.0001) with Dunn's multiple comparison post-test (p values for all pairs of columns shown in the figure).

(A) Umbilical cords were treated with either resting or inflammatory conditions for 16 to 20 h, then endothelial cells were isolated by collagenase P treatment, and expression of ICAM-1 in PECAM-1⁺ (endothelial) cells was analyzed by flow cytometry. (B) Representative echographic images from long and short axes of human umbilical cords treated with resting or inflammatory conditions and perfused with anti–ICAM-1–coupled Targestar^B microbubbles. Dashed yellow lines delineate the luminal area to distinguish the microbubbles attached to endothelium from free-flowing ones. The scatter plot shows contrast-enhanced ultrasound video intensity values measured in images from both treatments. Statistical analysis was performed using an unpaired t test with Welch's correction (p value shown in the figure).

(A) Hematoxylin and eosin staining of tissue slices from umbilical cords exposed to no treatment or to high mechanical index ultrasounds. Images on the left are full cross sections of the umbilical cords. The white boxed areas on them are shown at greater magnification to the right. Histology experiments were performed on 3 to 4 different cord segments for each condition, and 2 to 3 sections were analyzed from each segment (B) Immunostaining of tissue slices from umbilical cords shown in (A). Endothelial cells were stained with an specific marker (CD31) in red and nuclei were stained with DAPI. Bar = 40 µm. (C) Effect of high mechanical index ultrasound on vessel wall integrity. Umbilical cords were subjected as indicated to resting or inflammatory conditions for 20 h or, alternatively, filled with a SonoVue MB solution and treated with high mechanical index ultrasounds for 5 min (US + MB) or left untreated (no treatment). Cords were perfused with fluorescein isothiocyanate (FITC)/dextran, and samples processed for fluorescence microscopy analysis. The histograms show fluorescence intensity along the line depicted on the corresponding image. All images were acquired by confocal microscopy using the same photomultiplier parameters. Bar = 25 µm.

(A) Analysis of the tissue expression of enhanced green fluorescent protein after sonoporation of an umbilical cord artery at high mechanical index. 4',6-diamidino-2-phenylindole (DAPI) staining of nuclei (blue) was used to distinguish endothelial cells (EC) from muscle cells because the appearance of their nuclei reflects the orthogonal orientation of these cell types. Green signal corresponds to elastin autofluorescence in the vascular smooth muscle cell (VSMC) area, and orange signal corresponds to pseudocolored enhanced green fluorescenct protein (EGFP) after image analysis with Spectral Dye Separation tool by Leica Confocal Software. (B) Image showing the localization of intercellular adhesion molecule-1-enhanced green fluorescent protein at the plasma membrane of an endothelial cell grown ex vivo after high mechanical index sonoporation of a SonoVue-loaded umbilical cord vein. Bar = 20 µm.