Stem cells (SCs) hold great promise in cell therapy, tissue engineering, and regenerative medicine as well as pharmaceutical and biotechnological applications.
They have the ability to self-renew and the ability to differentiate into specialized cell types depending on the source of isolation. However, the use of SCs for clinical applications requires high quality and quantity of cells.
This requires large-scale expansion of SCs followed by efficient and homogeneous differentiation into functional derivatives. Traditional methods for cell maintenance and expansion rely on two-dimensional (2-D) culture techniques using plastic culture plates and foreign media. These methods provide limited expansion and the cells tend to lose clonogenic and differentiation capacity upon long-term passage. Recently, new approaches for stem cell expansion have emphasized three-dimensional (3-D) cell growth to mimic the in vivo environment.
Another type of stem cell, mesenchymal stem cells (MSCs), are isolated from adult sources such as bone marrow and adipose tissue, or perinatal tissues such as umbilical cord, cord blood, placenta, and amniotic fluid.
MSCs are characterized by adherent growth on plastic culture plates, exhibiting clonogenic growth, and are positive for mesenchymal surface markers, CD90, CD73, CD29, and CD105 and negative for hematopoietic lineage markers, CD45, CD34, and HLA-DR. Unlike pluripotent stem cells, MSCs are multipotent and differentiate into only limited cell types such as osteocytes, chondrocytes, and adipocytes.
In addition, MSCs derived from adult tissues are also affected by aging and exposure to environmental stresses, which may alter genomic stability. Compared to adult MSCs, MSCs obtained from perinatal tissues exhibit higher growth and stemness potential.
