title: Non-invasive dynamic near-infrared imaging and quantification of vascular leakage in vivo.
abstract: Preclinical vascular research has been hindered by a lack of methods that can sensitively image and quantify vascular perfusion and leakage in vivo. In this study, we have developed dynamic near-infrared imaging methods to repeatedly visualize and quantify vascular leakage in mouse skin in vivo, and we have applied these methods to transgenic mice with overexpression of vascular endothelial growth factors VEGF-A or -C. Near-infrared dye conjugates were developed to identify a suitable vascular tracer that had a prolonged circulation lifetime and slow leakage into normal tissue after intravenous injection. Dynamic simultaneous imaging of ear skin and a large blood vessel in the leg enabled determination of the intravascular signal (blood volume fraction) from the tissue signal shortly after injection and quantifications of vascular leakage into the extravascular tissue over time. This method allowed for the sensitive detection of increased blood vascularity and leakage rates in K14-VEGF-A transgenic mice and also reliably measured inflammation-induced changes of vascularity and leakage over time in the same mice. Measurements after injection of recombinant VEGF-A surprisingly revealed increased blood vascular leakage and lymphatic clearance in K14-VEGF-C transgenic mice which have an expanded cutaneous lymphatic vessel network, potentially indicating unanticipated effects of lymphatic drainage on vascular leakage. Increased vascular leakage was also detected in subcutaneous tumors, confirming that the method can also be applied to deeper tissues. This new imaging method might facilitate longitudinal investigations of the in vivo effects of drug candidates, including angiogenesis inhibitors, in preclinical disease models.
authors: Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology, ETH Zurich, Wolfgang-Pauli-Str. 10, HCI H303, 8093 Zurich, Switzerland.
authors: Steven T
authors: ST
authors: Proulx
authors: Paola
authors: P
authors: Luciani
authors: Annamari
authors: A
authors: Alitalo
authors: Viviane
authors: V
authors: Mumprecht
authors: Ailsa J
authors: AJ
authors: Christiansen
authors: Reto
authors: R
authors: Huggenberger
authors: Jean-Christophe
authors: JC
authors: Leroux
authors: Michael
authors: M
authors: Detmar
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D019559:Capillary Leak Syndrome / Q000175:diagnosis* / Q000473:pathology*; D002199:Capillary Permeability / Q000502:physiology; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D003952:Diagnostic Imaging / Q000379:methods*; D004121:Dimethyl Sulfoxide; D005260:Female; D007211:Indoles / Q000493:pharmacokinetics; D007259:Infrared Rays; D042601:Lymphatic Vessels / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D011092:Polyethylene Glycols; D012867:Skin / Q000473:pathology*; D013056:Spectrophotometry, Ultraviolet; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D042582:Vascular Endothelial Growth Factor C / Q000235:genetics / Q000378:metabolism
chemical_list: C427728:IRDye800; D007211:Indoles; D042461:Vascular Endothelial Growth Factor A; D042582:Vascular Endothelial Growth Factor C; D011092:Polyethylene Glycols; C028210:monomethoxypolyethylene glycol; D004121:Dimethyl Sulfoxide