- The Challenge of Regenerative Medicine
Interventions to replace undeveloped, destroyed, or degenerated tissues are not new. However, regenerating tissue was thought to be impossible. “Regenerative medicine” aims to actually regenerate tissue. Therefore, it presents a significant shift in the goal of medicine. Regenerative medicine employs three strategies: (1) inducing the body’s inherent regenerative capacities in vivo through the application of growth factors and/or stem cells; (2) “tissue engineering,” or creating complex structures in vitro containing cells and custom-made scaffolds to implant in the patient; and (3) recolonizing donated, decellularized structures with patient-derived cells and implanting them in the patient.
Regenerative medicine has been enthusiastically received as it promises to make further interventions redundant. Also, it may provide solutions for as-yet-untreatable conditions, and it may benefit anyone from neonates (possibly even fetuses) to the elderly. All medical fields have embraced it, from dentistry and orthopedics to neurosurgery and cardiology. Its growth is based on our increased knowledge of cell—and especially stem cell—biology and biomaterials, and on the increasing prevalence of degenerative diseases. In the future, regenerative medicine may therefore touch most of our lives.
While there has been a steady increase in the volume of medical research, the field has been largely ignored in bioethics. A PubMed search on “regenerative medicine” resulted in 1,385 papers in 2008, 1,595 in 2009, and 1,282 in the first seven months of 2010, of which respectively 38, 33, and 17 included “bioethics.” In the same years—2008, 2009, and 2010—the phrase “tissue engineering” resulted in 4,508, 5,024, and 3,387 papers, of which only 25, 17, and 12 included “bioethics.” A literature review of 2008 brought up 203 papers when the search was guided by this string: “regenerative medicine AND/OR tissue engineering AND ethic*.”1 All but thirteen of these articles appeared in biomedical journals, and, out of the thirteen exceptions, very few were in bioethics journals. The ethical issue most commonly addressed in all of the articles was the use of human embryonic stem cells.
These data might suggest that there are no new ethical issues involved in regenerative medicine. In fact, a number of ethical challenges may arise.
While the principles of regenerative medicine are easy to explain and the possible benefits even easier to appraise, relatively few products have made it into clinical trials, and even fewer into therapy. So far, we know some of the “vocabulary” of tissue formation—the genes, cells, growth factors, and extracellular environment involved—but we know very little of the “syntax” of healthy and affected tissues: how these elements interact during the tissue formation process, how the native tissue (healthy and affected) interacts with the new, and whether these interactions are unique for each individual or common for all persons. For now, regenerative medicine is more akin to tissue handicraft than tissue engineering: products are developed on a case-by-case basis, and most research energy is spent on identifying and combining the pieces of the puzzle, then translating these findings into a therapeutically active product.
Another challenge the development of regenerative medicine presents is that it is not being pursued by the usual actors—the big pharmaceutical companies that have the money, infrastructure, and clinical trial experience to bring a therapy to market. Rather, the driving forces behind regenerative medicine are cell biologists and biomaterials experts, many of whom are not acquainted with bioethical issues. Ethics committees, on the other hand, are often unfamiliar with regenerative medicine. This disconnect may make it difficult to design ethically acceptable clinical trials on regenerative medicine. There is also the considerable time it takes to go from bench to bedside—if the bedside is ever reached. This lag, and the huge investment necessary for small and medium-sized enterprises to develop these products, requires the participation of private investors. This investment is happening in an international context, where Western ethical sensitivities are not always the prime concern. Which products make it after their initial development may thus depend not only on their therapeutic merits, but also on the expected return-on-investment and on the playing field that is created by...