Mesenchymal stem cells (MSCs) are multipotent stem cells that can differentiate into a variety of cell types, including osteoblasts, chondrocytes, myocytes, and adipocytes. MSCs are of intense therapeutic interest, because they represent a population of cells with the potential to treat a range of acute and degenerative diseases. MSCs are advantageous over other stem cells types for a variety of reasons, including that they are immunoprivileged, making them an advantageous cell type for allogeneic transplantation.
Allogeneic means that cells from a donor are used in the treatment of a different person.
Overview of Mesenchymal Stem Cells (MSCs)
In addition to secreting factors that can stimulate tissue repair, MSCs can substantially alter their microenvironment, exerting effects that are both anti-inflammatory and anti-fibrotic. MSCs are also advantageous over other stem cells types, because they avoid the ethical issues that surround embryonic stem cell research and can positively impact immune function. Because of their unique capacity to form structural tissues, MSCs also being explored for use in 3D printing applications.
History of Mesenchymal Stem Cells (MSCs)
The discovery of mesenchymal stem cells (MSCs) dates back to the early 1900’s.
In 1924, the Russian-born researcher Alexander Maximow used histology to identify a type of precursor cell within the mesenchyme that could differentiate into a variety of blood cell types. While the term mesenchymal stem cell did not exist, this is the earliest known reference to the cell type.
Nearly 40 years later, in the 1960’s, researchers Ernest McCulloch and James Till identified the clonal qualities of marrow cells. , It then took another decade until an ex vivo assay was developed that allowed for examination of the clonal nature of multipotent marrow cells.
This assay was developed by Friedenstein’s team of researchers in the 1970’s, although the stromal cells of interest (now called mesenchymal stem cells) were referred as colony-forming unit-fibroblasts (CFU-f).
Although the first clinical trials of MSCs occurred in 1995, hundreds of clinical trials have since been initiated.
Interestingly, it took until the turn of the century (2000) for research supply companies to give enough credibility to the cell type to launch research tools that would support investigation of the cell type by the scientific community.
Later research and experimentation further characterized the plasticity of marrow cells and how their differentiation into mature cell types could be manipulated by environmental stimuli. For instance, growing marrow stromal cells in the presence of osteogenic stimuli, such as inorganic phosphate, ascorbic acid, dexamethasone, and related stimuli, can drive differentiation into osteoblasts (bone producing cells).
Similarly, the presence of transforming growth factor-best (TGF-b) has the ability to induce chondrogenic (cartilaginous) traits.
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