The amnion is the protective layer surrounding the fetus. During a C-section, this layer is usually thrown away, along with the placenta. For the last 100 years, however, surgeons have transplanted this amniotic tissue to prevent scar tissue formation after surgery. It worked — because the amnion produces growth factors and lubrication factors that stimulate healing, tame inflammation and promote tissue regeneration.
This amniotic tissue, with its stem cells and surrounding fluid, is rapidly replacing other forms of stem cells and growth factors in orthopaedics. It is as if the entire regenerative medicine world has discovered the source of life’s youthful elixir. Here is the state-of-the-art accelerating regenerative medicine and some facts to consider:
Different populations of fetal-derived stem cells have been isolated from amniotic fluid. These cells have the highest potential to differentiate into mature cells of bone and cartilage — and they don’t form tumors when injected in vivo. Most importantly, the cells produce (and the fluid contains) a high concentration of the growth factors needed for tissue repair and regeneration.
Here’s a comparison made in our collaborator’s lab: A 1cc vial of amniotic stem cells contains approximately 2 million cells with 2 to 50 times more growth factors than a PRP injection from blood platelets.
Even more promising is that the process of tissue remodeling — in reconstructed anterior cruciate ligaments, for example — usually takes 12 to 18 months. When the tissue does regenerate and mature, it usually has relatively small diameter collagen fibers. Normal ligaments are a mixture of small and large diameter fibers; small fibers alone are more typical of scar tissue.
Tissues treated with amniotic stem cells have been reported, in pilot studies, to regenerate with a normal composition of fibers both large and small. If this work is reaffirmed, it means that the entire field of tissue reconstruction may be modified. By including stem cells, we can induce normal, salamander-like regeneration with better tissues in a shorter time frame.
But there’s another side to the coin.
The stem cell field as a whole has become crowded with companies proclaiming remarkable results. Unfortunately, many of the products offered lack stringent quality control.
Cells grown in tissue culture often die after implantation. Freezing cells without careful cryopreservation techniques leads to vials of dead cells. There is a wide range of cell viability from different manufacturers; some commercial products having zero live cells and low growth factors. Bone marrow samples from people over 30 years old have very few active stem cells. Fat, while ubiquitous, is also sourced for stem cells, but has fewer growth factors and pleuripotential cells of the fetal amnion. Lastly, there are as yet no comparative or outcome studies documenting definitive tissue regeneration with any of the commercial preparations.
So the demand for stem cell therapy accelerates, and science is trying to catch up. The potential is extraordinarily high, and the risk of harm very low. When choosing which treatment is right for you, base your decision-making process on a combination of available data, physician expertise and intuition. Sound familiar?
Dr. Kevin R. Stone is an orthopedic surgeon at The Stone Clinic and chairman of the Stone Research Foundation in San Francisco.