Pause… stem cell therapy dogged by insufficient research

We aren’t quite in the place to say stem cell therapy can treat osteoarthritis and related conditions, in dogs or humans. TheGiantVermin/Flickr

A recent article published in the Herald Sun newspaper reported anecdotal evidence of animals almost crippled from arthritis or joint damage recovering their function after stem cell therapy.

Although the article refers to treatments for animals, a range of stem cell types are currently being evaluated for their regenerative capacity in a variety of potential clinical applications – in both human and animal studies.

But promises of instantaneous or miraculous cures must be viewed with caution until results can be verified by properly conducted preclinical and clinical trials, the results of which can be appropriately scrutinized.

Types of stem cells

Stem cells encompass a wide variety of cell types, including embryonic and post-natal (adult) blood and tissue-derived cells. They are characterised by their different biological properties.

Cells that are likely to have an impact in orthopaedic (musculoskeletal) applications are those with the capacity to differentiate into tissues such as bone or cartilage and/or are able to secrete factors that promote tissue repair and regeneration.

Laboratory studies have shown that some stem cell types possess anti-inflammatory properties and/or dampen immune responses, both of which could be responsible for the initial successes noted in the article above.

These combined characteristics, together with their regenerative capacity, make stem cells prime candidates for advancing current treatments in a range of clinical applications, including those related to orthopaedic damage or disease.

The stem cells in the newspaper article were taken from patients or young healthy donors and multiplied millions of times before being injected into inflamed joints.

This process of using stem cells from a donor of the same species is called allogenic transplantation, while re-administration of the patient’s own stem cells is called autologous transplantation.

Only some specific stem cell types can be used allogeneically (administered to a foreign recipient) because of the potential for rejection of some foreign stem cell types by the recipient’s immune system.

Developing treatments

The treatments mentioned in the newspaper article are being conducted under the direction of a highly respected immunologist who is the Director of the Monash Immunology and Stem Cell Laboratories at Monash University.

Hopefully the anecdotal results reported in the article will be verified by carefully conducted preclinical trials in animals that can inform potential similar trials in humans in the future.

Such preclinical trials on treatment of acute and chronic or degenerative musculoskeletal conditions are already being undertaken in Australia and internationally, predominantly through the publicly listed Australian biopharmaceutical company Mesoblast.

Mesoblast is the world’s leading developer of innovative biological products in the field of regenerative medicine, using adult-derived stem cells known as mesenchymal precursor cells.

These cells are a sub-population of adult mesenchymal stem cells that can be isolated from bone marrow and adipose (fat) tissue.

Relief at hand?

Osteoarthritis is the most common musculoskeletal disorder in animals and humans. It has been defined as a group of conditions that lead to joint symptoms of pain and disability together with radiological evidence of loss of articular cartilage (the smooth white tissue that covers the ends of bones where they come together to form joints).

Pathologically, the disease is characterised by extensive degradation of articular cartilage, largely in areas of high contact loading such as knee joints.

The therapeutic options for its management are limited with current treatments mainly relying on analgesics, corticosteroids and non-steroidal anti-inflammatory drugs (NSAIDs). So new types of treatment, such as use of specific stem cell types, are currently the subject of intensive research.

The claims that treatment of osteoarthritis can potentially be “cured” and that “stunning improvements occur in less than a week” remain unverified.

Initial improvements following cell-based therapies may be due to the anti-inflammatory properties of the injected cells. In this instance, it’s likely the improvements reported in the article are due to the acknowledged anti-inflammatory properties of the, presumably, mesenchymal stem cells that were injected.

But in assessing the potential of stem cell treatments for osteoarthritis sufferers, it’s important not to give premature hope through hyperbole by presenting results from preliminary observations that haven’t yet been properly verified by appropriately conducted peer-reviewed trials.

Damaged cartilage, particularly articular cartilage, can take weeks or months to heal after treatment. So a “cure” would be expected to take much longer than weeks and hasn’t yet be scientifically verified.

Since the preferred differentiation pathway for mesenchymal stem cells is to form bone, it’s necessary for such cells to be placed in an effective cartilage-forming (chondrogenic) environment before they can initiate repair in diseases such as osteoarthritis. Preliminary results are promising since such cells are capable of forming articular cartilage when cultured in the laboratory.

So although the verdict is out on the long-term efficacy of cell-based therapeutic treatments for osteoarthritis and related conditions, such treatment offers the promise of a potential cure for these debilitating diseases in the future.