| In the last few years, a number of methods have | | | | (donor unrelated) cells in our large animal model of |
| been developed to repair cartilage damage. These | | | | knee osteoarthritis, without any adverse events of |
| include osteochondral transplantation, microfracture | | | | the cells at all." |
| surgery and autologous chondrocyte (cartilage cell) | | | | Mesoblast's cartilage trials evaluated the |
| implantation. | | | | effectiveness and safety of the company's allogeneic |
| A feature common to all of these techniques is that | | | | adult stem cells to treat osteoarthritis of the knee in |
| they are limited to the repair of focal lesions. Patients | | | | 48 arthritic sheep joints. |
| with OA are excluded from treatment. | | | | The results showed that osteoarthritic sheep knee |
| OA cartilage lesions are usually larger and unconfined | | | | joints receiving Mesoblast's stem cells had significantly |
| and so do not provide an appropriate environment | | | | greater thickness of joint cartilage, reduced cartilage |
| for chondrocytes to be retained long enough to build | | | | breakdown, and greater biomechanical strength three |
| a framework (matrix). | | | | months later than did control joints receiving |
| So...successful repair of OA cartilage damage is | | | | hyaluronic acid. |
| dependent on the ability to form a matrix within the | | | | In another study, Duke University Medical Center |
| joint. | | | | researchers have "reprogrammed" adult stem cells |
| Effective cartilage engineering protocols have already | | | | taken from a small deposit of fat behind the kneecap |
| been developed in which chondrocytes in young | | | | into functioning cartilage, bone, or fat cells that could |
| animal models have been shown to be effective in | | | | potentially be grown into replacement tissues for |
| creating cartilage. | | | | osteoarthritis. |
| Generating cartilage using adult human cartilage cells is | | | | The research team has provided evidence that stem |
| far more challenging. Older OA patients have cartilage | | | | cells taken from different adult sources have the |
| that is less responsive to stem cell stimulation and | | | | potential to be transformed into multiple specialized |
| their stem cells seem to respond less well to the | | | | cell types. |
| usual growth factors. | | | | In the current study, the researchers took the fat |
| There are three potential avenues for obtaining stem | | | | pads from patients whose knee joints were |
| cells. The first are embryonic stem cells which have | | | | removed during total joint replacement surgery. The |
| the attraction of being relatively pristine. However, | | | | fat pad is a dense structure behind the patella, or |
| political and ethical interests have made this source of | | | | kneecap that is unlike typical fat tissue found |
| stem cells unobtainable. Plus, there is the theoretical | | | | throughout the body. |
| possibility that theses stem cells may grow | | | | They were able to isolate and grow adult stem cells |
| unchecked leading to unregulated growth, ie cancer. | | | | from this tissue. |
| A second source are mesenchymal stem cells grown | | | | According to scientists at Cardiff University, stem |
| in a laboratory from normal volunteers. While carefully | | | | cells identified in their studies can be turned into |
| screened for diseases and genetic problems, these | | | | cartilage cells (chondrocytes) in huge quantities. This |
| stem cells do carry the potential for possible rejection | | | | may mean that limitations in cartilage transplants, in |
| reactions. | | | | which healthy cartilage cells are collected and |
| Finally, the last source and the one that seems to | | | | transplanted into a damaged joint, could be |
| have the most promise- at least for now- are | | | | overcome. |
| autologous stem cells. These are stem cells | | | | However, despite recent media reports that heralded |
| harvested from the iliac crest of the patient. | | | | the identification of these stem cells as a |
| Autologous stem cells provide an attractive option | | | | breakthrough in the treatment of osteoarthritis, this |
| for osteoarthritis patients and their clinicians. However | | | | research is currently only being considered to treat |
| it must also be recognized that autologous therapies | | | | people with limited cartilage damage only. |
| are expensive. Ideally, it would be good to treat the | | | | Dr. Nathan Wei states, "Our current understanding of |
| specimen obtained from the iliac crest to growth | | | | stem cell biology is obviously not where it needs to |
| factors, cytokines, and chemokines, to stimulate an | | | | be. However, early work at our center using |
| increase in the number of stem cells. | | | | autologous stem cells obtained from iliac crest bone |
| However, both governmental regulations as well as | | | | marrow and then concentrated has shown very |
| sterility concerns preclude this step. | | | | promising results in patients with osteoarthritis of the |
| In addition, the search for better matrix production | | | | knee. It is important to comment on the fact that |
| to allow stem cells a "home" to grow in and multiply | | | | prior to introduction of the stem cells, irritation of the |
| is still being studied. | | | | cartilage and adjacent capsule is important to initiate |
| There have been a few clinical trials that have | | | | an inflammatory response which then leads to cell |
| demonstrated some promise. The first comes from | | | | proliferation which is an essential part of healing and |
| Murdoch University in Australia. | | | | subsequent cartilage regeneration." |
| Working with Australia's adult stem cell company, | | | | Dr. Wei adds, "For sure, though, I feel that this |
| Mesoblast Limited (ASX:MSB), the University's | | | | approach which is relatively painless will prove to be |
| pre-clinical trials of Mesoblast's patented adult stem | | | | more effective than other therapies we currently |
| cells had shown the therapy to significantly protect | | | | have for osteoarthritis." |
| cartilage against damage in knee osteoarthritis. | | | | For more information about stem cells and |
| The project's principal investigator, Professor Rick | | | | osteoarthritis, call the Arthritis and Osteoporosis |
| Read stated, "We are delighted with the significant | | | | Center of Maryland at (301) 694-5800. |
| cartilage protective effects of Mesoblast's allogeneic | | | | |