Umbilical Cord Blood

Stem cells are found in all multi-cellular organism. They retain the ability to renew themselves and can differentiate into a diverse range of specialized cell types. As stem cells can be grown and transformed into specialized cells with characteristics consistent with cells of various tissues such as muscles or nerves through cell culture, their use in medical therapies has been proposed.

In particular, embryonic cell lines, autologous embryonic stem cells generated through therapeutic cloning, and highly plastic adult stem cells from the umbilical cord blood or bone marrow are touted as promising candidates.

Compared with adult cells, umbilical cord blood hematopoietic stem cells produce larger hematopoietic colonies in vitro, have different growth factor requirements, are able to expand in long-term culture in vitro, and have longer telomeres. Umbilical cord blood transplantation for various hematopoietic reconstitutions and a lower incidence of graft-versus-host disease than expected with conventional therapies. Recently, it has been reported that umbilical cord blood contains mesenchymal progenitor cells capable of differentiating into marrow stroma, bone, cartilage, muscle, and connective tissues.

Here, with a view to utilize umbilical cord blood cells for cell transplantation into injured liver, we investigated the hepatic potential of umbilical cord blood cells both in vitro and in vivo. We determined the most efficient conditions leading umbilical cord blood cells to produce albumin. In a novel primary culture system supplemented with a combination of growth/differentiation factors, about 50% of umbilical cord blood cells in 21-day cultures expressed albumin, and the albumin cells coexpressed hepatocyte lineage markers. The albumin expressing cells were able to proliferate in the culture system.

Human umbilical cord blood cells can proliferate hepatocyte lineage cells in the original primary culture system in vitro, and differentiate into functionally mature hepatocytes in vivo. To our knowledge, this is the first evidence that human umbilical cord blood contains cells that produce endoderm-proliferating cells.

Umbilical cord blood is still in the early stages of use in scientific and medical research. Studying these cells will help researchers understand how they are able to transform into a wide array of more specialized cells that make up the human body. Some of the most serious medical conditions such as cancer and birth defects are caused by problems that occur somewhere in the cell process. A better understanding of how normal development occurs and disease processes can enable researchers to develop new and improved approaches to treating diseases and injuries.