Stem cell (SC) approaches hold much hope for the development of new tools to treat disease. However, therapeutic options based on them have only rarely found their way into clinical practice. Why is this so?
There continues to be a need for a better understanding of the basic science behind stem cells with respect to their diseased niche.[1] Further, the existence of conflicting evidence regarding the role of stem cells makes it hard to interpret their significance in a specific disease context.[2,3] Angiogenesis and tumor therapy are relatively new approaches in stem cell therapy, where researchers have found promising results for a clinical application.
We, for example, have recently shown that mesenchymal stem cells (MSC) are capable of expressing a lymphatic phenotype when exposed to lymph-inductive media and purified VEGF-C. Migratory activity towards VEGF-C in vitro suggests homing capability in vivo. Restoration of lymphatic drainage after injection of mesenchymal stem cells in a lymphedema model indicates that mesenchymal stem cells play a role in lymphatic regeneration, with a potential clinical application.[4]
A new approach connects stem cells with selective gene therapy to enhance the options for regeneration or replacement of diseased or missing cells, as well as for tumor destruction.[5] The minimum requirement for beneficial gene therapy is the sustained manufacture of the therapeutic gene product in the correct biological context with minimal harmful side effects.[6,7] In order to achieve such end, 2 requirements must be met. First, the development of new strategies for modulating therapeutic gene expression, and secondly, methods for the efficient delivery of foreign genes into stem cells are required.[8] Stem cell engineering and a better understanding of basic stem cell biology will lead to therapeutic applications of stem cells that ultimately will have to prove its role in the clinical setting.
That is my opinion. I am Dr. Claudius Conrad, Harvard Medical School and Harvard Stem Cell Institute, Massachusetts General Hospital.
Footnotes
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References
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