Cord and Cord Blood: Valuable Resources with Potential for Liver Therapy

Abstract

Liver cirrhosis and/or liver malignancies have been nominated the 5th leading cause of death worldwide. The WHO reported, in 2006, that 20 million people around the globe suffer from some form or other of severe liver illness. The ultimate fate of end-stage liver disorders is hepatic dysfunction and eventually organ failure. Unfortunately the only curative mode of management for liver failure is liver transplantation, which is subject to many limitations. Novel alternatives, such as artificial and bio-artificial support devices only aid in temporary replacement of some liver function until an organ is available for transplantation. These newer modalities also have drawbacks or remain experimental and still demand further controlled trials to allow proof of concept and safety before transferring them to the bedside. Regenerative medicine and stem cell therapy has recently shown promise in the management of various human diseases. Recent reports of stem cell plasticity and its multipotentiality has raised hopes of stem cell therapy offering exciting therapeutic possibilities for patients with chronic liver disease. Although there exists a choice of stem cells that have been reported to be capable of self-renewal and differentiation to hepatobiliary cell lineages both in vitro and in vivo including, rodent and human embryonic stem cell, bone marrow haematopoietic stem cell, mesenchymal stem cell, umbilical cord blood stem cells, fetal liver progenitor cell, adult liver progenitor cells; it may be argued that with a global population of 6 billion people and a global birth rate in access of 130 million per year, placenta and the umbilical cord possibly provide the most readily accessible and ethically sound alternative source of stem cells. UCB-derived liver cells can be potentially exploited for gene therapy, cellular transplant, bio-artificial liver-assisted devices, drug toxicology testing and use as an in vitro model to understand the developmental biology of the liver. Here we review the latest scientific developments relevant for future liver cell therapy.