It’s difficult to find information on stem cells being harmful in people. A better question is how do stem cells know what to become in the body once injected?
If you’re injecting stem cells into an encapsulated joint like the knee the stem cells stay in that joint. Stem cells have the ability to repair, rebuild and rejuvenate tissues in the body. You already have millions of stem cells inside of your body. As we age those cells get sluggish and just aren’t as robust as “new” stem cells.
When disease or injury occurs, stem cells respond to specific signals and set out to facilitate the healing process by differentiating into specialized cells. These specialized cells then release healing growth factors in response to the distress cell signal in an injured or pathologic area of the body required for the body’s repair. The body handles this process of differentiation into the proper tissue by gene expression.
If you’ve never had a genetics course in college that’s okay. Here is some basic terminology.
Gene expression is the cellular process of creating a protein, instructed by the sequence of DNA contained within a gene. This process begins with a signal, initiating transcription of a gene. The product of transcription, mRNA, travels out of the nucleus. It interacts with specific protein machinery to transcribe the mRNA sequence into amino acid chains that fold into proteins.
Cell fate decision is the product of differential gene expression, a cell fate decision describes how exposure of stem cells to different external or internal environments can activate transcription/translation of different genes or sets of genes, producing multiple specific end-stage results.
The parent stem cell will become a self-renewed cell or a daughter cell which will differentiate into the tissue the body needs. See the diagram below.
These stem cells will replicate repeatedly. So over the course of many months millions of new cells may be created.
Because humans are 99.9% the same, the DNA framework of an undifferentiated cell is basically the same as your own. When introducing a homologous (from an another person) biologic such as a stem cell, you might think the chance of rejection would be high, however, this isn’t the case when discussing UMSC’s (umbilical mesenchymal stem cells) from donated umbilical cord martix. In an NCBI study it states, “in order for UMSC’s to survive host rejection, they either actively modulate the inflammatory response or they present cell surface components that enable them to remain invisible to the host immune system.” See study no. 1 below pertaining to the eye. These UMSC’s seem to do this very well.
Some common injuries and conditions we use stem cell therapy for in the office include:
- meniscus tear
- ligament tear,
- muscular tear
- Donor rejection?: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4156039/