We appreciate the interest in our recently published review article [Citation1] and would like to thank Dr Katz and his colleagues for the positive feedback. In this response to the letter to the editor, we address some of their concerns.
The goal of our article was to review preclinical and clinical data on the targeted treatment of myocardium with therapeutic drugs, growth factors, genes, and stem cells from a variety of anatomical orientations or routes. We specifically attempted to describe the pros and cons of each route in broad terms as well as applications across a spectrum of myocardial pathologies. We did not attempt to review all of the adjunctive technologies to enhance delivery to myocardial tissue, including microspheres, pressurized ballistic delivery, and many others.
Nor did we attempt to review treatment of vascular tissues. Indeed, a Pubmed search using the search terms ‘drug eluting coronary stents’ yields over 10,780 references and many excellent reviews have been written over the last two decades. We maintain that drug deposition in the myocardium following intracoronary administration does not lead to meaningful drug retention in this highly perfused muscle.
However, we appreciate Dr Katz highlighting the ongoing innovative developments that may help implement local myocardial therapies. We have not seen any recent review articles that summarize nanoparticle formulations [Citation2], cellular modification to enhance gene transfer [Citation3] and adjunctive technologies such as sonoporation [Citation4], electroporation [Citation4], magnetofection [Citation5], pressurized ballistic delivery via ‘needleless’ liquid jet methodology [Citation6,Citation7], and other approaches aimed to enhance local myocardial delivery. We believe that, given their expertise in the field, Dr Katz and colleagues can successfully fill this niche.
Once again, we would like to thank Dr Katz and his colleagues for their insightful critique of our review article.
Declaration of interest
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
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References
- Maslov M, Foianini S, Lovich M. Delivery of drugs, growth factors, genes and stem cells via intrapericardial, epicardial and intramyocardial routes for sustained local targeted therapy of myocardial disease. Expert Opin Drug Deliv. 2017;22:1–13.
- Fargnoli AS, Mu A, Katz MG, et al. Anti-inflammatory loaded poly-lactic glycolic acid nanoparticle formulations to enhance myocardial gene transfer: an in-vitro assessment of a drug/gene combination therapeutic approach for direct injection. J Transl Med. 2014;12:171.
- Stephan MT, Moon JJ, Um SH, et al. Therapeutic cell engineering with surface-conjugated synthetic nanoparticles. Nat Med. 2010;16:1035–1041.
- Katz MG, Fargnoli AS, Bridges CR. Myocardial gene transfer: routes and devices for regulation of transgene expression by modulation of cellular permeability. Hum Gene Ther. 2013;24:375–392.
- Dobson J. Gene therapy progress and prospects: magnetic nanoparticle-based gene delivery. Gene Ther. 2006;13:283–287.
- Fargnoli AS, Katz MG, Williams RD, et al. A needleless liquid jet injection delivery method for cardiac gene therapy: a comparative evaluation versus standard routes of delivery reveals enhanced therapeutic retention and cardiac specific gene expression. J Cardiovasc Transl Res. 2014;7:756–767.
- Nishizaki K, Mazda O, Dohi Y, et al. In vivo gene gun-mediated transduction into rat heart with Epstein-Barr virus-based episomal vectors. Ann Thorac Surg. 2000;70:1332.