Bioengineering a New Heart When a heart is failing, there are not many treatments options available other than transplanting a donor heart that is in better condition. Although this method has been proven to be effective, the patient with the new heart will face a life of immunosuppression drugs and laundry list of possible other complications, including issues with their kidneys and that is if they are lucky enough to obtain a donor heart. As the science of bioengineering progresses, the possibility for creating replacement organs no longer seems to be just an idea. With the rate of heart failure on the rise and the severe lack of donor hearts, scientists have been working on several potential new treatments, injectable biomaterial, myocardial patches, and even a whole bioartificial heart, but these new biotechnologies bring upon a slew of bioethical issues that must be sorted out before the science will be able to advance. As of 2008, heart failure is a condition that affects about 22 million people worldwide, 5 million of those cases are in the United States. Those numbers have only been growing. Once a heart has reached end-stage failure, the only option for that patient is to have a donor heart transplanted. This whole procedure, while it has been proven to work, is much more complicated than just cutting out someone’s heart and sewing it into someone else. Several aspects have to be similar for a donor heart to be properly matched, such as the donor’s and recipient’s body size and weight. Location to the hospital is also another consideration, due to the fact that thoracic organs can only survive outside the body for about 4-6 hours. On top of that, the major histocompatibility complex (MHC) must be as similar as possible; the body will reject the organ if they are too different. With the millions of possible MHCs, an exact match is very unlikely, so the recipient will then have to use drugs to suppress the immune system for the rest of his or her life. The operation itself has a risk of organ rejection, sepsis, and other secondary infections. The required use of immunosuppression drugs after the operation will only increase the risk of developing the mentioned difficulties. The kidney issues that appear after a transplant are typically caused by the immunosuppression drugs themselves. With all the complications associated with heart transplants, any type of new technology in this field has many obstacles to overcome to prove it is a better treatment. Scientists have been developing technologies that will not only increase the availability of donor hearts, but will also dissolve the need for immunosuppressive drugs and may even disband the need for the heart transplant surgery all together. Tissue engineering seems to be the most promising technology in organ replacement. The idea behind this technology is utilizing as much of the patient’s own cells as possible. This eliminates the many of the problems with organ rejection and immune system suppression. To create this bioartifical heart, a donor heart is essentially washed with detergents to remove all of the cells that belonged to the previous owner, but leaving the main structural framework of the heart. The recipient’s cells are then grown and allowed to attach to the empty scaffold, thus creating a new, structurally sound, and functional heart. There have been some setbacks with this procedure such as low survival rates for the newly grown cells and the inability to fully impregnate the donor heart with the grown cells. One group of research have successfully decellularized and re-cellularized rat hearts. Eight days of maturation later, the hearts were drug responsive and contracting. Researchers are making progress with these difficulties, but clinically acceptable applications are still some years away. Other ways that tissue engineering is aiding in the search for new heart transplant technologies is by trying to avoid the need for a transplant at