Tuesday, October 4, 2011

Stem cell treatment found to restore spinal functions

Experiments with human stem cells that have been directed to differentiate into spinal cord tissue were found to be effective in restoring motor functions in mice. The cells transformed themselves into all the necessary cell types of the spinal cord, and mice receiving the treatment showed improved recovery after functional damage was induced. The next step would be testing the cells in humans, making it a promising treatment for patients that are permanently disabled because their spinal cord is damaged. Transforming stem cells is not new, but because the scientists have shown functional improved in damaged mice, their treatment is very promising.

The stem cells differentiated into neurons, the electrical wiring of the nervous system. In addition, they also differentiated into astrocytes and oligodendrocytes, accompanying cells that are also found in the spinal cord and the brain. The three cell types represent the major nerve cell lines that are found in the central nervous system, showing that the stem cell treatment can accurately replace the damaged cells in spinal cord injury. The injected cells connected to the still functional cells present in the spinal cord of mice receiving the treatment. In addition, formation of new blood vessels was shown. This indicates that the treatment is making functioning tissue out of the cells, which was further demonstrated by the fact that mice receiving the treatment showed improved functional recovery over mice that did not receive the stem cells. They had more control over there motor functions and were able to walk faster. Because this kind of therapy involves the risk of tumour formation, the scientists checked whether the mice would develop cancer over time: after about 4 months, there was still no tumour formation, indicating that the treatment is safe, even though more long-term studies are required.

To create the cells used for treatment, the researchers started with cells that reside predominantly in the skin: fibroblasts. These simple cells were reversed into a more primitive stage with stem cell capabilities. For this, a certain 'cocktail' of genes was built in, a technique that has been developed over ten years ago, and has since then revolutionized the use of stem cells. With this technique, it is possible to convert regular cells back to stem cells, without having to use the embryonic version which cause a lot of controversy. Nowadays, these so-called induced pluripotent stem cells (iPS) have more or less replaced embryonic stem cells. Not only because they are less controversial, but also because the risk of tumour formation is smaller.

It is likely that the differentiated iPS cells also function in humans: the cells themselves are already of human origin. Though, stem cell treatment is still controversial, and more safety studies in animals are likely to be required before the first human testing can be performed. Safety experiments in primates are already planned.

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