Subject(s)
DNA/administration & dosage , Gene Transfer Techniques , Genetic Therapy , Plasmids/genetics , Ultrasonics , Animals , Chloramphenicol O-Acetyltransferase/metabolism , Enzyme-Linked Immunosorbent Assay , HeLa Cells , Humans , Liposomes/administration & dosage , Mice , NIH 3T3 Cells , Plasmids/chemistry , TransfectionSubject(s)
Colonic Neoplasms/therapy , DNA/administration & dosage , Gene Transfer Techniques , Genetic Therapy , Plasmids/genetics , Ultrasonics , Adenocarcinoma/therapy , Animals , Carcinoma, Squamous Cell/therapy , Cations , Chloramphenicol O-Acetyltransferase/metabolism , Enzyme-Linked Immunosorbent Assay , Humans , Interleukin-12/administration & dosage , Liposomes/administration & dosage , Mice , Muscles/metabolism , Plasmids/chemistry , Transfection , Tumor Cells, CulturedABSTRACT
RATIONALE AND OBJECTIVES: New targeted microbubbles directed to the GPIIb IIIa receptor have been developed. The objective was to determine whether targeting microbubbles to clots would enhance ultrasound imaging. Systematic studies were designed to determine whether in vitro methodology is an acceptable predictor of in vivo efficacy. MATERIALS AND METHODS: Bioconjugate ligands were inserted into lipid-coated membranes of perfluorocarbon gas microbubbles and binding studies performed on activated platelets immobilized on cell culture plates. Targeted microbubble binding to clots in a flow through chamber was also assessed. Finally, microbubble binding studies on arteriolar and venular clots in a mouse cremasteric muscle model were conducted. RESULTS: Binding studies on platelet-immobilized plates demonstrated an affinity for targeted microbubbles versus untargeted microbubbles. Semiquantitative light obscuration techniques helped to measure extent of targeted microbubble binding. Targeted microbubbles similarly bound to platelet clots in the flow model. Finally, studies in the mouse model confirmed binding of targeted microbubbles in both venules and arterioles. CONCLUSION: The use of receptor selective targeted microbubbles improved binding to vascular thrombi in both in vitro and in vivo settings.
Subject(s)
Contrast Media/chemical synthesis , Contrast Media/pharmacokinetics , Platelet Aggregation/drug effects , Thrombosis/diagnostic imaging , Ultrasonography/methods , Animals , Fluorocarbons , Ligands , Male , Mice , Mice, Inbred C57BL , Microspheres , Photomicrography , Platelet Glycoprotein GPIIb-IIIa Complex/metabolismABSTRACT
Microbubbles, currently used as contrast agents have potential therapeutic applications. Microbubbles, upon insonation of sufficiently intense ultrasound will cavitate. Cavitation with microbubbles can be used to dissolve blood clots or deliver drugs. Targeting ligands and drugs can be incorporated into microbubbles to make highly specific diagnostic and therapeutic agents for activation with ultrasound. In this paper I will review some of these potential applications and experimental results using such agents for thrombolysis, drug and gene delivery.
Subject(s)
Drug Carriers , Genetic Therapy/methods , Microspheres , Thrombolytic Therapy/methods , Ultrasonic Therapy/methods , Contrast Media , Genetic Therapy/instrumentation , Humans , Thrombosis/diagnostic imaging , Thrombosis/therapy , UltrasonographyABSTRACT
We tested the hypothesis that targeted disruption of cationic microbubble-linked plasmid DNA, using diagnostic ultrasound, may aid transfection of large animal myocardium. Plasmid DNA encoding for CAT (pCAT, chloramphenicol acetyltransferase) was bound to a novel cationic microbubble containing MRX-225 for intravenous administration, and 16 dogs in 4 groups variously received this conjugate or plasmid only, or were exposed to ultrasound. Histochemical staining and enzyme-linked immunosorbent assay analysis showed CAT activity in the myocardium of only those animals that received microbubble-linked DNA and were exposed to ultrasound. Thus, disruption of cationic-linked, low-dose plasmid systems by diagnostic ultrasound may facilitate transfection of large animal hearts.