Specific targeting of human inflamed endothelium and in situ vascular tissue transfection by the use of ultrasound contrast agents.
OBJECTIVE
We used human umbilical cord segments as an ex vivo model to investigate the possible clinical diagnostic and therapeutic applications of microbubbles (MBs).


BACKGROUND
Microbubbles are commonly used in clinical practice as ultrasound contrast agents. Several studies have addressed the in vivo applications of MBs for specific targeting of vascular dysfunction or sonoporation in animal models, but to date no human tissue model has been established.


METHODS
Primary venular endothelial cell monolayers were targeted with MBs conjugated to an antibody against a highly expressed endothelial marker (tetraspanin CD9), and binding was assessed under increasing flow rates (0.5 to 5 dynes/cm(2)). Furthermore, CD9-coupled MB endothelial targeting was measured under flow conditions by contrast-enhanced ultrasound analysis in an ex vivo human macrovascular model (umbilical cord vein), and the same tissue model was used for the detection of inflamed vasculature with anti-intercellular adhesion molecule (ICAM)-1-coated MBs. Finally, plasmids encoding fluorescent proteins were sonoporated into umbilical cord vessels.


RESULTS
Specific endothelial targeting in the in vitro and ex vivo models described previously was achieved by the use of MBs covered with an anti-CD9. Furthermore, we managed to induce inflammation in umbilical cord veins and detect it with real-time echography imaging using anti-ICAM-1-coupled MBs. Moreover, expression and correct localization of green fluorescent protein and green fluorescent protein-tagged ICAM-1 were assessed in this human ex vivo model without causing vascular damage.


CONCLUSIONS
In the absence of clinical trials to test the benefits and possible applications of ultrasound contrast agents for molecular imaging and therapy, we have developed a novel ex vivo human model using umbilical cords that is valid for the detection of inflammation and for exogenous expression of proteins by sonoporation.
Barreiro
Olga
O
Servicio de Inmunología, Hospital de la Princesa, Universidad Autónoma de Madrid, Madrid, Spain.
Aguilar
Río J
RJ
Tejera
Emilio
E
Megías
Diego
D
de Torres-Alba
Fernando
F
Evangelista
Arturo
A
Sánchez-Madrid
Francisco
F
D015703:Antigens, CD / Q000276:immunology; D015415:Biomarkers / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D003287:Contrast Media / Q000378:metabolism / Q000627:therapeutic use; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging* / Q000276:immunology / Q000378:metabolism; D006801:Humans; D018796:Immunoconjugates / Q000378:metabolism / Q000627:therapeutic use; D007249:Inflammation / Q000000981:diagnostic imaging* / Q000276:immunology / Q000378:metabolism; D018836:Inflammation Mediators / Q000276:immunology; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology; D008562:Membrane Glycoproteins / Q000276:immunology; D045423:Microbubbles; D060245:Tetraspanin 29; D014162:Transfection / Q000379:methods*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014464:Ultrasonic Therapy; D014465:Ultrasonics; D014463:Ultrasonography; D014470:Umbilical Cord / Q000000981:diagnostic imaging* / Q000276:immunology / Q000378:metabolism
D015703:Antigens, CD; D015415:Biomarkers; C554869:CD9 protein, human; D003287:Contrast Media; D018796:Immunoconjugates; D018836:Inflammation Mediators; D008562:Membrane Glycoproteins; D060245:Tetraspanin 29; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1