Stem cell therapy for rheumatoid arthritis
In rheumatoid arthritis (RA), the immune system mistakenly attacks the tissue that lines the joints, which can cause pain, inflammation, swelling, and stiffness.
This inflammation can extend to the cartilage that covers the ends of joints and cause irreversible damage and loss of function. It can also damage other tissues, including the lungs, heart, kidney, skin, and eyes.
Stem cell therapy may help reduce inflammation and increase the presence of healthy cells in the body. This article outlines the current knowledge on stem cell therapy as a possible treatment for RA.
What is stem cell therapy?
A stem cell is a type of cell not specialized to perform a specific role. Instead, it has the unique ability to develop into one of many different types of cell.
Stem cell therapy uses stem cells to replace dead and diseased cells within the body.
The human body contains over 200 different types of cell. Usually, each type has certain characteristics that allow it to perform a specific role.
Cells with similar roles group together to form tissues, which then organize to form the body's organs. For example, the heart is a collection of muscle tissues.
Scientists source the stem cells from body tissue, either from an embryo or an adult human, and isolate them in the laboratory. After manipulating the cells to develop into specific types, they then inject the cells into the recipient's blood or tissue.
How can it help treat RA?
Researchers are investigating ways of using stem cells to control inflammation and regenerate damaged tissues.
RA causes inflammation in the tissues between joints. This results in a loss of cartilage, which is the connective tissue that cushions the joints. Over time, cartilage loss can damage the joint and nearby bone.
Mesenchymal stem cells (MSCs) are types of stem cell that can develop into cartilage and bone. Synovial MSC therapy involves injecting these cells directly into the tissues surrounding the affected joints.
Some research shows that MSCs are also able to suppress the immune system and reduce the body's inflammatory response. This makes MSC therapy a promising treatment option for autoimmune conditions such as RA.
Although some clinics use stem cell therapy to treat arthritis, it is not standard practice and may have some serious side effects. Stem cell research is still in the very early stages of scientific investigation and needs more analysis.
What the research says
One 2013 study investigated the efficacy of MSC therapy for people with RA.
All 172 participants continued to take their regular RA medication during the course of the study. A subset of the participants also received two MSC treatments via intravenous injection, while another subset received placebo injections (the controls).
Compared with the controls, those who received the MSC treatment showed a significant remission of the condition. The team measured the extent of remission using the improvement criteria of the American College of Rheumatology, the 28-joint disease activity score, and the Health Assessment Questionnaire.
Improvements also correlated with increased levels of regulatory T cells (RTCs) in the blood. RTCs stop the immune system from attacking the body's own cells. As such, they play a vital role in controlling inflammation.
One 2015 study reported similar effects of MSCs on the immune cells of mice with RA.
Its authors explain that MSC treatment increased RCT levels while lowering levels of cells that promote inflammation.
The Food and Drug Administration (FDA) state that clinical trials of MSC therapy for inflammatory conditions have not produced consistent results.
Until recently, researchers sourced human MSCs (hMSCs) from a range of tissues and donors. These different cell batches can vary greatly in their ability to suppress the immune system.
In 2017, scientists began developing reliable methods for predicting the efficacy of different batches of hMSCs. Conducting further research using these methods may help scientists determine whether stem cell therapy can help treat RA.
Currently, the FDA only approve the use of umbilical hematopoietic stem cells (uHSCs).
These cells derive from umbilical cords and can develop into different types of blood cell. People mainly receive uHSCs to help treat blood disorders.
The FDA do not regulate the use of other types of stem cell, such as MSCs. However, they may approve and oversee clinical trials that use such cells.
Clinical trials take place under an FDA-permitted Investigational New Drug Application, which indicates that the trial meets their safety standards.
Risks and side effects
Stem cell therapy can cause some health complications.
Such complications are likely to be much more common than official figures suggest, however, as unregulated clinics that provide these treatments do not need to report adverse health effects in their patients.
Examples of complications that can arise from stem cell treatments include:
Any time a cell leaves the body, it can become contaminated with viruses and bacteria.
When a healthcare professional injects these cells into a person's body, these pathogens can cause the person to become sick.
Even cells that come from the recipient's own body can cause an infection or spread an existing infection.
Exacerbation of RA
According to one 2014 review, the use of synovial MSCs to treat arthritic joints has the potential to worsen RA.
Injecting MSCs directly into joint tissue triggers the development of synovial fibroblasts. These are cells that play a role in joint inflammation and destruction.
The authors of that same 2014 review note that intravenous administration of MSCs could suppress the immune response, which protects against cancerous cells.
This could allow cancerous growths to manifest more easily.
Potential long-term risks
Most stem cell research is still in the early stages of clinical trials, so scientists are unsure of the potential long-term risks of this type of therapy.
According to the FDA, further clinical trials are necessary to establish whether — and to what extent — the benefits of stem cell treatments outweigh the risks.
The International Society for Stem Cell Research offer the following advice for people considering stem cell treatments:
- Avoid clinics that offer unregulated treatments.
- Avoid treatments that have not undergone successful clinical trials.
- Avoid participating in research that is not part of an FDA-approved clinical trial.
- Talk to a doctor or rheumatologist about the potential risks of stem cell therapy.
- Beware of clinics that downplay the risks associated with their treatments.
- Beware of clinics that use patient testimonials and persuasive language in place of scientific evidence.
Stem cell therapy is still a relatively new area of research. However, early trials suggest that such therapies may be effective against a range of autoimmune conditions, including RA.
MSCs are one type of stem cell that seems to show promise for the treatment of RA. Studies show that these cells can suppress immune system overactivity, which helps control chronic inflammation.
However, the FDA do not currently regulate the use of stem cells as a treatment for RA. Scientists have conducted too few studies to confirm that such treatments are safe or effective.
People should be wary of clinics that offer these treatments. It is also best to speak to a doctor or rheumatologist before starting a new treatment.
Those who wish to take part in a clinical trial should check to make sure that it is FDA-approved.