Many researchers and physicians are interested in using stem cells to treat a variety of musculoskeletal conditions, including arthritis. But what are stem cells?
Scientists define stem cells as cells that can do both of these things:
- Self renew. Stem cells can divide and duplicate themselves, both in the body and in a lab. A small amount of stem cells can be harvested from human tissue and then grown in a lab.
- Differentiate. Stem cells can develop into different types of cells. For example, it is possible for a stem cell to develop into a blood cell, bone cell, or cartilage cell.
Babies develop from a single stem cell, called an embryo cell. Scientists believe that stem cells are essential to the body’s ability to repair damaged cells, such as healing after an injury.
The most common type of stem cells used in therapy are mesenchymal stem cells.
Mesenchymal Stem Cells
Sometimes called adult stem cells, mesenchymal stem cells have the potential to develop into musculoskeletal cells, such as fat, bone, or cartilage cells. Many researchers believe mesenchymal stem cells have the potential to repair and replace cartilage as well as other tissue damaged by arthritis.
Mesenchymal stem cells are usually collected from the patient’s fat tissue, blood, or bone marrow.
Adipose (fat) stem cells. Fat tissue contains stem cells. Physicians who use adipose stem cells will harvest the cells using surgery or liposuction. Some physicians prefer to use stem cells from the small fat pad below and behind the knee, called the infrapatellar fat pad.1
See Knee Anatomy
Peripheral blood stem cells. Found in the bloodstream, these stem cells are normally considered immature blood cells, but they have the potential to develop into other types of cells, including cartilage cells.
Bone marrow stem cells. Bone marrow stem cells have been the most researched2 and are considered to have the best potential for developing into cartilage cells.3 To get these cells, a doctor usually takes bone marrow from the patient’s pelvic bone using a needle and syringe, a process called bone marrow aspiration.
Once harvested, these cells are either:
- Cultured in a lab, or
- Processed into a concentrated solution.
Another type of mesenchymal stem cells are cord stem cells. Cord stem cells can be collected from a newborn’s umbilical cord blood and frozen until needed, a process that can be expensive. In addition, some stem cell experts question whether treating musculoskeletal injuries with cord stem cells is effective. More research is needed.
Additional uses for mesenchymal stem cells
Some researchers theorize that mesenchymal stem cells have the potential to develop into more than just musculoskeletal cells—that they may be used someday to replace or repair damaged organ cells or nerve cells, for example. Other researchers are skeptical. More study is needed in this area.
Other Types of Stem Cells
Mesenchymal stem cells are not the only type of stem cells, but they seem to have the most promise and the least risk when compared to other types of stem cells. For example, some experts suspect that embryonic stem cells and another type of stem cell that can be developed in labs, called induced pluripotent stem cells, have the potential to cause benign tumors or trigger an unwanted immune response in the patient.4 In addition, embryonic stem cells are currently banned in the United States.