A recently published open access paper provides a good short overview of the current state of development for stem cell transplants - essentially the first generation of therapies to follow right on the heels of the ability to identify and culture stem cells. It covers the high points:
- A great deal of work is presently taking place in the field and progress is rapid.
- Results to date have been encouraging: the benefits are more than enough to make continuing research and development worthwhile.
- Evidence suggests that transplanted stem cells trigger healing largely through release of signalling biochemicals that spur native cells to greater efforts - rather than any other method, such as cell division to reestablish cell population.
- The state of the local cellular environment is a big concern - and potentially a big influence on the success of a therapy. In the old, the dysfunctional cellular environment may cause a therapy to fail because its damaged signals outweigh those of the transplanted cells.
- Infrastructure technologies need a great deal more work: sourcing stem cells for transplant needs to be much easier, cheaper, and more reliable.
From the paper:
Preclinical and clinical trials of stem cell therapy have been carried out for treating a broad spectrum of diseases using several types of adult stem cells. While encouraging therapeutic results have been obtained, much remains to be investigated regarding the best cell type to use, cell dosage, delivery route, long-term safety, clinical feasibility, and ultimately treatment cost. Logistic aspects of stem cell therapeutics remain an area that requires urgent attention from the medical community.
Recent cardiovascular trial studies have demonstrated that growth factors and cytokines derived from the injected stem cells and host tissue appear to contribute largely to the observed therapeutic benefits, indicating that trophic actions rather than the multilineage potential (or stemness) of the administered stem cells may provide the underlying tissue healing power.
However, aging and disease can adversely affect the host tissue into which stem cells are injected. A better understanding of the host tissue response in stem cell therapy is necessary to advance the field and bridge the gap between preclinical and clinical findings.
One intriguing view of the future is that stem cell therapies will prove to be a short-lived intermediary technology. If it is the signals that are triggering healing, then cell transplants could be done away with entirely - we only need them now because researchers do not yet understand how to reproduce the same chemical signalling that the cells deliver. This evolution might well happen over the next decade, and researchers who work with stem cells will focus instead on producing organs grown from a patient's own cells and other feats of tissue engineering.