Sources for Cell Therapy
Sources for Cell Therapy
There are two levels of cell therapy sources to consider: the person providing the original cells and the type or location of those cells. At the highest level, cell therapies generally start in one of two places:
The Patient: Some cell therapies start with the patient. Doctors can collect a small amount of blood, bone marrow or other tissue and turn it into a cell therapy. When a patient receives cell therapy made from their own cells, that therapy is considered autologous.- A Donor: Some cell therapies start with a donor. Scientists may collect a small amount of blood, bone marrow or other tissue from the donor. That tissue can then be processed to ensure it is safe and free of communicable diseases. Then, a doctor may use the donated cells or tissues to treat a different person. When a patient receives cell therapy made from a different person’s cells, that therapy is considered allogeneic.
Autologous cell therapies generally carry fewer risks than allogeneic. This difference stems from the fact that autologous therapies essentially move the cells a patient already has.
For example, bone marrow concentrate procedures remove some tissue and blood from the hip. After collecting the helpful part of that tissue, it is given back to the same patient. The procedure simply puts the useful for healing part of the patient’s own bone marrow, in a location where it can be more helpful.
This contrasts sharply with allogeneic cell therapies. Since these therapies come from outside the patient, they automatically carry risks that autologous therapies do not. These risks include the potential for immune system rejection and infection with a blood-borne illness.
Doctors and patients can mitigate these risks by choosing autologous cell therapies. Autologous cell therapies can come from several sources. The most common autologous cell therapy sources are bone marrow and blood.
Bone Marrow Aspirate and Bone Marrow Concentrate
Bone marrow makes a good cell therapy source for several reasons. First, it contains many important components of the healing process, including:
- Endothelial progenitor cells (EPCs)
- Hematopoietic stem cells (HSCs)
- Anti-infective immune cells
- Mesenchymal stem cells (MSCs)
- Platelets
- Proteins that encourage healing
Risks of Donor-Derived (Allogeneic) Cell Therapies
Allergy Risk: Allogeneic therapies typically require some amount of laboratory-based processing. Depending on what happens in the lab, the cells may contain potentially allergenic materials. If the patient has an allergy to part of the cell therapy, they could develop a potentially serious allergic reaction.
Rejection Risk: Allogeneic therapies come from one person and go to a different recipient. The recipient’s immune system can recognize these cells and attack them as foreign material. Some allogeneic treatments depend on the cells exerting their effects quickly. If allogeneic cells can do this, they may help the patient despite later being attacked and cleared by the immune system.
Infection Risk: Allogeneic therapies come from a donor who may or may not have a communicable infection. Even with proper donor screening, allogeneic therapies carry a non-zero risk of infecting recipients with a donor-derived infection.
Mesenchymal stem cells (MSCs) are adult stem cells found in all people. MSCs serve as the body’s natural resource for repairing and regenerating damaged connective tissues. MSCs can help repair bones, tendons and cartilage. This property may explain why so many doctors have used bone marrow aspirate and concentrate in orthopedic conditions. The difference between these two cell therapies is simple.
Bone marrow aspirate is simply bone marrow containing-blood that is collected and used without processing. Bone marrow aspirate does not usually have a high enough concentration of MSCs to be therapeutically useful in most orthopedic conditions.
Bone marrow concentrate (BMC) is processed bone marrow aspirate that has MSCs and platelets in 6x-12x smaller volume than aspirate. To make BMC, a specialist puts bone marrow aspirate in a regulated medical device, such as the NextGen Stem Cell BMC. The device then spins in a centrifuge.
Blood and Platelet Rich Plasmat
Blood contains many of the same components as bone marrow aspirate. However, it does not contain mesenchymal stem cells. Still, the platelets, immune cells and proteins in blood can encourage healing. This makes blood a good source for cell therapy.
The most common blood-based cell therapy is platelet rich plasma (PRP). Platelet rich plasma is processed blood that contains platelets and immune cells at 4x to 6x higher concentrations than blood. To make PRP, a specialist puts blood into a regulated medical device, such as the ART PRP. The device spins in a centrifuge.
Centrifugation allows the platelets and immune cells to gather in the collection area. After centrifugation, the specialist removes the fluid in the collection area. This fluid is platelet rich plasma (PRP). PRP contains platelets and other cells in clinically effective amounts. Doctors can place this concentrated cell therapy in smaller areas, such as knee joints, elbows, and wrists.
NOTE: Many PRP devices and systems exist, but they do not all achieve the same end product. Some start with such a small volume of blood that it is impossible for them to turn out an effective PRP. Others lose nearly 50% of platelets during processing.
This is wasteful and doesn’t give patients the best chance of a good outcome. The ART PRP system provides high platelet recovery and is the only PRP system with optional in-line ultrafiltration of plasma proteins. This makes it the most versatile and powerful PRP system in the world.
Birth-Related Tissues
Due to the relative ease of collection, researchers have explored using birth tissues as cell therapies. Amniotic tissue, cord blood and amniotic fluid have all been studied. Though these tissues contain cells and proteins that might be useful in some conditions, they are by definition allogeneic. As such, applications for these products have been fairly limited thus far.