Why store cord tissue?
Like cord blood, the umbilical cord tissue is a rich source of stem cells. However, they are a different population of stem cells from the ones in cord blood. While most of the stem cells in cord blood are blood-forming or hematopoietic stem cells (HSC), most of the stem cells in cord tissue are mesenchymal stem/stromal cells (MSC). The MSC are not distributed uniformly in the cord, but are mostly clustered around the walls of the blood vessels. The typical umbilical cord is estimated to hold 11 million MSC per gram of tissue.
The fact that cord blood and cord tissue hold different types of primitve cells explains why it is valuable to consider storing both.
Schugar RC et al. 2009; Journal of Biomedicine and Biotechnology 2009:789526 (open access) doi:10.1155/2009/789526