Delivery of Stem Cells to Porcine Arterial Wall with Echogenic Liposomes Conjugated to Antibodies against CD34 and Intercellular Adhesion Molecule-1

In atherosclerosis, the loss of vascular stem cells via apoptosis impairs the capacity of the vascular wall to repair or regenerate the tissue damaged by atherogenic factors. Recruitment of exogenous stem cells to the plaque tissue may repopulate vascular cells and help repair the arterial tissue. Ultrasound-enhanced liposomal targeting may provide a feasible method for stem cell delivery into atheroma. Bifunctional echogenic immunoliposomes (BF-ELIP) were generated by covalently coupling two antibodies to liposomes; the first one specific for CD34 antigens on the surface of stem cells and the second directed against the intercellular adhesion molecule-1 (ICAM-1) antigens on the inflammatory endothelium covering atheroma. CD34+ stem cells from adult bone marrow were incubated on the ICAM-1-expressing endothelium of the aorta of swine fed high cholesterol diets, which was preloaded with BF-ELIP. Significantly increased stem cell adherence and penetration were detected in particular in the aortic segments t...