Abstract 15171: Development of Targeted Drug Delivery Agents for Cardiac Regeneration
IIntroduction: Coronary heart disease is a leading cause of death in developed nations and currently available drugs only slow the progression of heart faliure. Given that regenerative agents will likely need to be precisely delivered to the infarct/border zone to fully realize cardiac regeneration, we hypothesized that suitable targeting ligands could be identified by biopanning a phage display library in a mouse model of myocardial infarction (MI).
Methods: A phage display library was biopanned in vivo to identify peptides specific for the infarct/border zone of the heart 4 days post-MI. After three rounds of biopanning, 50 phage clones were selected from the infarct and 50 from the border zone and their DNAs were amplified and sequenced. Peptide sequences were deduced from DNA sequences and phage clones were grouped (4 clones/group) based on their phylogeny and sequence similarity. Each group was then labeled with a near IR fluorescent dye (VT 680) and mixed with negative control phage clone (Panc-27) labeled with a second dye (VT 750). The specificity was determined by measuring heart: liver VT 680 / heart: liver VT 750 at times 0 and 4h post-injection on day 4 post-MI.
Results: Of the 23 groups that were screened, we eliminated 9 groups that had specificity value of 20 or less at t=4 h by FMT. Similarly, we determined the specificity of individual clones from groups with high specificty. Our screening strategy benefited from the fact that following in vivo and ex vivo imaging of hearts, fluorescence microscopy was applied to the same hearts to determine the distribution of the VT 680-tagged phage clones in the infarct/border zone along with the associated cell types.
Conclusions: We were able to identify phage clones specifiic to the heart by FMT and at the same time determined their distribution in the infarct area in relation to the associated cell types. The resulting peptide sequences can now be used to target the delivery of regenerative agents to the infarct/border zone after MI.
- © 2013 by American Heart Association, Inc.