Cryosections of liver tissue were stained with a monoclonal rat antimouse CD31 antibody (BD Biosciences) as well as with a monoclonal goat antihuman vWF antibody (C-20, Santa Cruz) followed by a suitable secondary

antibody conjugated with Alexa fluor 488 (Invitrogen) to highlight microvessels. Sections were counterstained for nuclei Navitoclax in vivo with Vectashield Mounting Medium with DAPI (Vector Laboratories). Microvessel density (MVD) was determined by counting the CD31 positive vessels in three high-power fields (×100 magnification) from areas of highest vascularization. 21 The vWF-positive cells were quantified using NIH ImageJ software. Immunohistochemical staining of the monoclonal rat antimouse CD34 antibody (BD Biosciences) was performed on deparaffinized tissue sections using a routine avidin-biotin-immunoperoxidase technique (Vectastain ABC kit, Vector Laboratories). Before incubation with the primary antibody, tissue sections were subjected to microwave treatment with Citrate-based Antigen Unmasking Solution Ivacaftor cost (Vector Laboratories), followed by a 20-minute cool-down and treatment with 3% hydrogen peroxide. Angiogenesis-related perfusion was assessed by two-dimensional SonoVue-enhanced ultrasound imaging using a clinical imaging system (Acuson S2000, Siemens Healthcare). A multi-D matrix array transducer was attached to a device and the acoustic focus was placed on the

level of the dorsal liver capsule. After tail vein injections of mice with 50 μL diluted SonoVue (Bracco; diluted 1:5 with 0.9% NaCl), imaging in CPS-mode with a rate of 13 frames/sec for 40 seconds was performed. A region of interest (ROI) was set within the liver and the area under the curve (AUC) was

quantified for this ROI. The values were normalized by the AUC of an ROI placed in the caval vein (Supporting Fig. 1). Fluorescence labeling of VEGFR2 antibody was performed with VivoTag-S680 (VisEn Medical) by way of NHS ester. Normal goat IgG antibody (AF644 and AB-108-C, R&D Systems) was used as isotype control. Antibodies were diluted in 200 μL carbonate/bicarbonate Glycogen branching enzyme buffer to concentrations of 1 mg/mL and incubated each with 6 μL VivoTag-S680 for 1 hour at room temperature. Nonreacted VivoTag-S680 fluorophores were separated from labeled antibodies by size exclusion chromatography with fast protein liquid chromatography (FPLC) (ÄKTApurifier 10, GE Healthcare). Subsequently, VivoTag-S680 labeled VEGFR2 and IgG probes were injected in CCl4-treated Cxcr3−/− and WT littermates by way of a tail vein catheter (100 μL). Probe enrichment in the liver was determined 6 hours after probe injection using fluorescence molecular tomography (FMT 2500; Visen). Additionally, low-dose μCT scans (TomoScope DUO, CT Imaging) were performed and coregistered to the 3D FMT data in order to add anatomical information. Isolation of total protein and RNA from snap-frozen liver tissue samples were performed as described.