| Research on stem cells is leading scientists to | | | | tissue in which they reside. A blood-forming adult |
| investigate the possibility of cell-based therapies to | | | | stem cell in the bone marrow, for example, normally |
| treat disease, which is often referred to as | | | | gives rise to the various types of blood cells such as |
| regenerative medicine. | | | | red blood cells, white blood cells and platelets. Until |
| Stem cells have two important characteristics that | | | | recently, it had been thought that a blood-forming cell |
| distinguish them from other types of cells. First, they | | | | in the bone marrow could not give rise to the cells of |
| are unspecialized cells that renew themselves for long | | | | a very different tissue. |
| periods of time through cell division. The second is | | | | However, a number of experiments over the last |
| that under certain physiologic or experimental | | | | several years have raised the possibility that stem |
| conditions, they can be induced to become cells with | | | | cells from one tissue may be able to give rise to cell |
| special functions. | | | | types of a completely different tissue. This |
| There are two different sources of stem cells. | | | | phenomenon is referred to as "plasticity." |
| Embryonic cells are derived from fetal tissue and are | | | | Two research presentations this past year shore up |
| a source of great controversy. Adult stem cells | | | | the promise of stem cells in arthritis. First, research |
| (ASC), on the other hand, are found in normal people. | | | | presented in April 2008 at the UK National Stem Cell |
| ASC can renew themselves, and can differentiate to | | | | Network Annual Science Meeting in Edinburgh offered |
| yield the major specialized cell types of the tissue or | | | | hope that stem cells may be harnessed to repair the |
| organ. Their primary role in a living organism is to | | | | damaged cartilage that is one of the main symptoms |
| maintain and repair the tissue in which they are found. | | | | of osteoarthritis. |
| Research on adult stem cells has recently generated | | | | On a related note, scientists at Cardiff University in |
| a great deal of excitement. Scientists have found | | | | the United Kingdom have successfully identified stem |
| adult stem cells in many more tissues than they once | | | | cells within articular cartilage of adults, which have the |
| thought possible. This finding has led scientists to ask | | | | ability to become chondrocytes, cells that make up |
| whether adult stem cells could be used for | | | | cartilage. The team has even been able to identify |
| transplants. In fact, adult blood forming stem cells | | | | the cells in people over 75 years of age. |
| from bone marrow have been used in transplants for | | | | Lead researcher Professor Charlie Archer from the |
| 30 years. Certain kinds of adult stem cells seem to | | | | Cardiff School of Biosciences said: |
| have the ability to differentiate into a number of | | | | "This research could have real benefits for arthritis |
| different cell types, given the proper conditions. | | | | sufferers and especially younger active patients with |
| Bone marrow derived stem cells give rise to a | | | | cartilage lesions that can progress to whole scale |
| variety of cell types: bone cells (osteocytes), | | | | osteoarthritis." |
| cartilage cells (chondrocytes), fat cells (adipocytes), | | | | According to Dr. Nathan Wei, a rheumatologist and |
| and other kinds of connective tissue cells such as | | | | clinical investigator in Frederick, Maryland, "We are |
| those in tendons. | | | | focusing our efforts on adult autologous stem cells |
| According to information from the National Institutes | | | | ("autologous" meaning derived from the patient |
| of Health, "One of the fundamental properties of a | | | | himself). These cells are present within a patient's |
| stem cell is that it does not have any tissue-specific | | | | bone marrow. Once we obtain the stem cells, they |
| structures that allow it to perform specialized | | | | need to be concentrated using special techniques in |
| functions. Unlike muscle cells, blood cells, or nerve | | | | order to secure the number of stem cells per unit |
| cells-which do not normally replicate themselves-stem | | | | volume needed. We have been using this treatment, |
| cells may replicate many times. | | | | combined with growth factors obtained from other |
| When cells replicate themselves many times over it is | | | | cells, for both osteoarthritis of the knee as well as |
| called proliferation. A starting population of stem cells | | | | the hip. Preliminary results using both subjective as |
| that proliferates for many months in the laboratory | | | | well as objective measures show much promise. If |
| can yield millions of cells." | | | | these results are validated, the springtime of your life |
| The process by which unspecialized stem cells | | | | when it comes to weight-bearing joints may actually |
| become specialized cells is called differentiation. Adult | | | | be 55-75. |
| stem cells typically generate the cell types of the | | | | |