Ann Thorac Surg 2006;81:167-168
© 2006 The Society of Thoracic Surgeons
Original article: Cardiovascular
Invited commentary
Marc Ruel, MD, MPH,
Erik J. Suuronen, PhD
Departments of Surgery, and Cellular and Molecular Medicine University of Ottawa Heart Institute, 40 Ruskin St, Suite 3403, Ottawa, Ontario, K1Y 4W7 Canada
(Email: mruel{at}ottawaheart.ca; esuuronen{at}ottawaheart.ca).
Nowadays one of the most interesting fields of cardiac surgical research is arguably that of cardiac tissue regeneration. The successful, specific, and controlled regeneration in humans of functional cardiomyocytes or of the blood vessels that supply them is the Holy Grail that could one day become a first line of therapy for nonurgent patients with heart failure or myocardial ischemia. Eventually it is possible that less biologically-based, more mechanical interventions such as ventricular assist device implantation, heart transplantation, coronary artery bypass grafting, or even percutaneous coronary interventions may be relegated to the care of acutely ill, unstable, or therapeutically unresponsive patients.
Numerous strategies are currently being explored to accomplish this. In the present article, Kanamori and colleagues [1] examined one of many available tissue-engineering approaches by using omentum, which may act as a cellular scaffold and locally provide regulatory and growth factors, to possibly promote bone marrow cell survival, viability, and function after cell transplantation in a large-animal model. It is important to note that currently no evidence of efficacious electromechanical contractility of bone marrow or other cells after ex-vivo sorting, culture, and transplantation exists, and that the results presented in this article make no exception to this. In the present article as in others, the improvements in contractility observed after transplantation of bone marrow cells may have resulted from a paracrine angiogenic effect on pre-existing contractile cells remaining within or near the myocardial scar, from alterations in fibrosis, or from increased recruitment and viability of circulating inflammatory or progenitor cells. As the viability of nonscaffolded bone marrow cells is less than 10% after transplantation into the heart, improving post-delivery viability with tissue-engineered methods constitutes a main research focus within the field of cardiac cellular regeneration, and this article describes one of several possible ways to try to accomplish this, although the authors have not examined specific cellular outcomes after transplantation within the experimental groups.
Ultimately the optimal approach to cardiac regeneration may well consist of simply promoting an appropriate milieu to amplify the recruitment of circulating stem cells that are present in the circulation and physiologically harbor in small numbers in the heart [2], without using exogenous cells or gene therapy, but rather by using ligands for stem cell adhesion receptors such as L-selectin [3].
Therefore, this article constitutes an interesting basic research contribution, but its pre-clinical impact is limited as several other tissue-engineering methods exist, such as the use of degradable biopolymer matrices, that may equally or better accomplish the goal of presumably increasing cell delivery, homing, and viability noninvasively, without the need to bring the omentum onto the heart.
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References
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- Kanamori T, Watanabe G, Yasuda T, Nagamine H, Kamiya H, Koshida Y. Hybrid surgical angiogenesisomentopexy can enhance myocardial angiogenesis induced by cell therapy. Ann Thorac Surg 2006;81:160-168.[Abstract/Free Full Text]
- Quaini F, Urbanek K, Beltrami AP, et al. Chimerism of the transplanted heart N Engl J Med 2002;346:5-15.[Abstract/Free Full Text]
- Biancone L, Cantaluppi V, Duo D, Deregibus MC, Torre C, Camussi G. Role of L-selectin in the vascular homing of peripheral blood-derived endothelial progenitor cells J Immunol 2004;173:5268-5274.[Abstract/Free Full Text]
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