The research team took two groups of goats and created osteoarthritis in their knees by removing the medial meniscus and cutting out the anterior cruciate ligament. After six weeks, one group of goats received an injection of sodium hyaluronan (a lubricant commonly used to treat symptomatic osteoarthritis of the knee) while the other group received a single dose of 10 million stem cells, originally extracted from the goats' bone marrow, and then suspended in sodium hyaluronan before injection into the knee.



In the knees which had been treated by stem cell injections, researchers observed a regeneration of joint tissue and a decrease in cartilage degeneration.

The authors commented on their findings… "there may be a therapeutic benefit associated with local delivery of stem cells following traumatic injury to the knee. The longer term effect of this may be a reduction or delay in the progression to osteoarthritis."

The authors concluded that “this is a scaffold-free method for cell delivery and is therefore unencumbered by the complexities associated with placement of a solid cell construct.” This latter statement is important because so many techniques to date have involved the complicated use of different scaffolds (frameworks) to hold stem cells in place.

Stem cells are progenitor cells- the cells that all others are derived from. They have three interesting characteristics that make them prime candidates for tissue regenerative techniques. They are capable of dividing and renewing their numbers for an unusually long period of time; they are undifferentiated, meaning they have not yet committed to being a “heart” cell or a “lung” cell; and they can become any type of specialized cell. Another term to refer to this property is that stem cells are “pluripotential.”

While most research and ethical concerns have been centered on the use of embryonic stem cells, adult stem cells are more accessible with no ethical “baggage.” The cells that were used in the above study were adult stem cells obtained from the bone marrow.

At the Arthritis and Osteoporosis Center of Maryland, research efforts have been aimed at using adult stem cells obtained from the bone marrow to treat osteoarthritis of the knee or hip. Stem cells are obtained from the iliac crest of the patient's hip and then concentrated using a special technique. The area of interest- usually the medial compartment of the knee is then prepared with a special instrument under ultrasound guidance. This technique ensures that local inflammation is created at the site of needed repair. This is a critical component of the procedure since the exact location of pathology will determine where the stem cells will be placed.

Along with stem cells, platelet rich plasma, also obtained from the patients is infused. The platelet rich plasma attaches to tyrosine kinase receptors on the cell surface of the stem cells and triggers gene expression within the nucleus of the stem cell. This “turns on” the stem cell to divide and differentiate into cartilage.

The entire procedure is done using local anesthetic with ultrasound guidance.

According to Dr. Nathan Wei, “Preliminary results are very promising. Longer term data is required and we are specifically addressing not only patient function but also measurements of cartilage thickness.” He adds, “the best approach as far as framework preparation for the stem cells and ensuring an adequate number of stem cells are of key importance. If you don't have enough viable stem cells, the procedure won't be effective. Also, the stem cells need to be primed properly… and have a scaffold (framework) to attach to. ”