May 20th, 2024
Adipose (Fat) Tissue and its Benefits in Treatment for Osteoarthritis
Osteoarthritis is the most common chronic degenerative joint disease in the United States, especially among the elderly population.[1] Over-the-counter medications, physical therapy, and other conservative measures are helpful in the initial stages of joint disease. However, continued loss of cartilage can lead to worsening symptoms and outcomes. Injectable substances, such as corticosteroids, platelet-rich plasma, and hyaluronic acid, help to control pain but do not assist with the healing process.[1]
Research into the healing properties of stem cells has been increasing in recent years. Human mesenchymal stem cells (MSCs) can restore and separate themselves into different tissue types in the human body. With these abilities, MSCs support tissue regeneration and cartilage repair.[1] Major sources of MSCs are found in the placenta, bone marrow, peripheral blood, and adipose tissue.[2] Research has found that using MSCs harvested from adipose tissue can positively affect joint health.
Adipose Tissue and Stem Cells
Adipose tissue contains multiple cell types. One-third of adipose tissue volume in the body is made up of mature adipocytes (fat cells), that are used for insulation and energy storage. The remaining adipose tissue volume contains preadipocytes (immature fat cells), MSCs, fibroblasts (connective tissue cells), pericytes, endothelial progenitor cells, macrophages, T-cells, and erythrocytes; this mixture of cells is also known as the stromal vascular fraction (SVF). Researchers are exploring the SVF to determine how it helps with tissue regeneration. Specifically, MSCs appear to be the key to beneficial results.[3]
These adipose MSCs have been shown to stimulate human dermal (skin) fibroblast production and movement, Additionally, MSCs promote collagen creation by activating paracrine factors (signals that facilitate cell communication over a short distance) and direct cell-to-cell contact.[3]
How Do We Get Adipose MSCs?
Adipose tissue comes in two types: brown and white. Brown adipose tissue is much less common and not typically harvested for MSCs. White adipose tissue is found under skin and around viscera. The major sites of skin adipose tissue are around the thigh, buttock, abdomen, upper arm, and breast. The primary sites of visceral adipose tissue surround the internal organs of the intestines, omentum, and kidneys.[3]
Adipose tissue must be harvested from the sites using aspiration, through a procedure known as liposuction. This procedure removes subcutaneous fat using a cannula under negative pressure. The collected aspirate contains adipose cells, saline, local anesthetic, and blood. These substances must be separated in order to isolate the MSCs.
First, the adipose tissue is minced and then is put into a solution containing collagenase (an enzyme). This solution encourages tissue digestion, leaving behind floating mature adipocytes, a watery solution in the middle, and a pellet containing SVF.[3] This process has historically been done in a laboratory setting.
Recently, medical devices for harvesting adipose tissue have been devised to harvest tissue and prepare it for injection in a closed system. An example of one of these devices is LipoGems.[4] This device is FDA-cleared for collection and preparation of a person’s adipose tissue for injection. This device has been used in several studies exploring MSCs and osteoarthritis.[5,6] To use the LipoGems device, a small incision is made in the abdominal or upper buttock area, and a small amount of fat tissue is collected. The device uses sterile saline to wash and resize the fat tissue into smaller pieces. The tissue is then injected into the treatment area.[4]
Does Adipose Tissue Help with Osteoarthritis?
Patients with osteoarthritis who undergo adipose MSC injections have reported decreased pain, as well as increased function and quality of life for up to two years after the injection.[7] These results were seen from early-stage osteoarthritis, up to grade 4 severity.[5]
Hudetz et al. found that intra-articular injection of adipose tissue positively affected bone cells’ growth and the production of an extracellular matrix (cell network, resulting in better-quality cartilage.[6]
Sciarretta et al. also found significant improvement in reported pain and functional outcomes after damaged cartilage was treated with a one-step injection of adipose tissue MSCs. These improvements continued for five years. They also found radiographic evidence of cartilage repair, with a decrease in the area of the bony defect and complete repair of the defect in most cases. There were no signs of bone overgrowth or swelling.[8]
Conclusion
Adipose tissue MSCs have been shown to improve pain, function, and quality of life for people suffering from osteoarthritis. This procedure is becoming more common as techniques improve, providing the opportunity to impact more people. Adipose tissue injection is minimally invasive and can be done on an outpatient basis, thereby reducing costs. If you are dealing with joint pain that is no longer controlled by conservative management, you may wish to discuss adipose tissue MSC injection with your orthopedic doctor.
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