Bioprosthetic valves such as porcine valves or implantable mechanical valves that are currently in common use can often lead to thrombosis or failure in the long term. In the past, scientists have tried to cultivate valve cells from bone marrow mesenchymal stem cells (BM-MSCs), however, obtaining these BM-MSCs is much more invasive and BM-MSCs have a much lower proliferation rate, especially in older patients. To address these problems, researchers have developed a method to create a patient-specific heart valve replacement from their own skin cells.
In order to create a viable valve replacement, researchers take skins cells from the patient and cause them to revert back into induced pluripotent stem cells (iPSC). They are able to coax the iPSCs into becoming heart cells and then seed them into a decellularized valve scaffolds. The researchers tried multiple cell seeding techniques to repopulate a pulmonary valve scaffold, and they found that using a static-rotary-static culture gave optimal infiltration into the scaffold. Ultimately, the researchers used immunohistochemistry to determine increased cellularity and increased expression of smooth muscle actin and other components in the extra cellular matrix to confirm functionality of the cultured tissue. In the future, this approach allows scientists to form a variety of valve tissues such as valve interstitial cells and not just pulmonary valve cells. Also, by taking cells directly from the patient, the cultured pulmonary valve will be patient specific thus lessening the risk of rejection by the patient’s immune system.
Current heart valve replacements do not grow along with the patient’s body, and pediatric surgical patients usually need reoperation as they age. This new technology in cellular tissue engineering is especially imperative for valve replacements in children. The study has only been done in vitro and further studies will be done to observe valve performance in vivo.
Press release from the Society of Thoracic Surgeons: Skin Cells Can Be Engineered…
The Annals of Thoracic Surgery: Engineered Patient-Specific Valves…
