Multipotent, Pluripotent, and Totipotent Stem Cells and Induced Pluripotent Stem Cells
Stem cells are undifferentiated cells that have two characteristics: they give rise to different mature cell types and have the ability to self-renew. However, not all stem cells have the same potential. Multipotent stem cells are capable of producing multiple, but not all, cell types. For example, mesenchymal stem cells (MSCs) give rise to cells of the bone, cartilage, muscle, and fat. MSCs are commonly found in the bone marrow, umbilical cord (Wharton’s jelly), and fat tissue. Pluripotent stem cells, like embryonic stem cells, are capable of producing all cells of the human body. Finally, totipotent stem cells can give rise to all cell types of the human body plus extra-embryonic tissues like the placenta. Totipotent stem cells are found only during the early stages of embryonic development.
Given the immense research interest in stem cells and the hesitancy to use human embryonic stem cells for research purposes, scientists have developed a way to generate pluripotent stem cells in vitro. Using adult cells derived from the skin or blood that have been reprogrammed, these induced pluripotent stem cells can be used to study stem cell biology or the mechanisms that determine differentiation in different tissue types.
Check out the Lifeline® catalog, which offers the following stem cell systems:
- Human Mesenchymal Stem Cells – (Adipose-derived)
- Normal Human Mesenchymal Cells – Wharton’s Jelly
- Normal Human Bone Marrow-derived Mesenchymal Cells
- Normal Human Pre-Adipocyte Cells
Recent Research Using Lifeline® Human MSCs from Wharton’s Jelly
Bone grafts are a common way to treat injuries to bone that cannot fully heal on their own. Bone morphogenic protein 2 (BMP-2) is a growth factor that stimulates bone growth and recombinant human BMP-2 (rhBMP-2) is approved by the FDA for use with a collagen sponge for the treatment of bone defects. However, given its short half-life, rhBMP-2 often is given in very high doses.
In a study this year in Stem Cells Translational Medicine, Andrews and colleagues set out to develop an injectable biologic therapy for bone defects using MSCs engineered to overexpress BMP-2 that are seeded in a chondroitin sulfate glycosaminoglycan (CS-GAG) hydrogel. CS-GAGs are found in the extracellular matrix of bone and cartilage tissue and support bone development.
Using Lifeline® MSCs from Wharton’s jelly (uMSCs), the authors first confirmed that uMSCs transduced with a lentiviral vector overexpressed BMP-2 as expected. BMP-2-expressing MSCs were then seeded on CS-GAG hydrogels and their activity was compared with that of collagen sponges containing rhBMP-2 (Col+rhBMP-2). The authors found that the release of rhBMP-2 from collagen sponges occurred quickly, while release of BMP-2 from CS-GAG hydrogels was more sustained over time.
Using an animal model of bone injury, the authors next tested the ability of their CS-GAG-MSC-BMP-2 hydrogel to repair bone defects. They found that their CS-GAG hydrogels containing BMP-2-expressing MSCs repaired bone in a comparable fashion as the collagen sponges containing rhBMP-2. Additional research will determine whether the sustained release of BMP-2 over time is clinically advantageous compared with the current standard of rhBMP- 2 containing collagen sponges.
Together, the results of this study suggest that CS-GAG hydrogels containing BMP-2-expressing MSCs are viable for use in bone repair therapies.
Keep up with us every other week here on the blog to learn how researchers are using Lifeline® products. If you are using our products, let us know and your study could be featured next!