Defining umbilical cord blood stem cells

Umbilical cord blood is the blood found in the vessels of the umbilical cord and placenta. It has been shown that this blood contains at least three populations of stem cells, each with unique features and properties. Due to the absence of standardized criteria for characterizing and naming cord blood stem cells, different terms and acronyms have been introduced to describe certain cell populations. Besides the confusion caused by the introduction of these different names, some of the terms used by different groups are inaccurate and misleading when considering the molecular and cellular properties of such cells. Hence, in this review we provide simple and direct descriptions of different populations of stem cells in umbilical cord blood in an attempt to clarify the confusion caused by the existence of multiple names given to certain cord blood stem cells. We also discuss the potential use of umbilical cord blood stem cells as a therapeutic tool for several diseases and disorders in light of ongoing clinical trials.