Potential application of cord blood-derived stromal cells in cellular therapy and regenerative medicine.

Neonatal stromal cells from umbilical cord blood (CB) are promising alternatives to bone marrow- (BM-) derived multipotent stromal cells (MSCs). In comparison to BM-MSC, the less mature CB-derived stromal cells have been described as a cell population with higher differentiation and proliferation potential that might be of potential interest for clinical application in regenerative medicine. Recently, it has become clear that cord blood contains different stromal cell populations, and as of today, a clear distinction between unrestricted somatic stromal cells (USSCs) and CB-MSC has been established.

DLK-1 as a marker to distinguish unrestricted somatic stem cells and mesenchymal stromal cells in cord blood.

In addition to hematopoietic stem cells, cord blood (CB) also contains different nonhematopoietic CD45-, CD34- adherent cell populations: cord blood mesenchymal stromal cells (CB MSC) that behave almost like MSC from bone marrow (BM MSC) and unrestricted somatic stem cells (USSC) that differentiate into cells of all 3 germ layers. Distinguishing between these populations is difficult due to overlapping features such as the immunophenotype or the osteogenic and chondrogenic differentiation pathway. Functional differences in the differentiation potential suggest different developmental stages or different cell populations.