I searched the news this morning for items related to stem cell disease therapies. I found over 60 items. My impression is that the situation is a bit like commercial aviation was in 1926: everybody is talking about it, visionaries are sure it will be a very big thing, there is a lot of disconnected activity going on all over the place, and safety is a big question. And, the regulatory rules-of-the-game still have to be worked out. Most potential stem cell therapies are still far from being part of mainline medicine and it is difficult to make sense about where things stand.
The most practiced approach to stem cell therapy is to take autologous (a patient’s own) mesenchymal or hematopoietic stem cells from the patient’s bone marrow, grow the numbers of them in culture, and reintroduce them into the body in a way that hopefully leads to cure of a diseases or organ regeneration. Use of a patient’s own stem cells avoids problems of immune system rejection encountered when other people’s stem cells are used. Mesenchymal stem cells (MSCs) “ – are multipotent stem cells that can differentiate into a variety of cell types. Cell types that MSCs have been shown to differentiate into in vitro or in vivo include osteoblasts, chondrocytes, myocytes, adipocytes, and, beta-pancreatic islets cells(ref).” Hematopoietic stem cells (HSCs) are also multipotent cells that can differentiate into “all of the blood cell types including myeloid (monocytes and macrophages, neutrophils, basophils, eosinophils, erythrocytes, megakaryocytes/platelets, dendritic cells), and lymphoid lineages (T-cells, B-cells, NK-cells)(ref).”
There are also other approaches, such as using other autologous stem cells (like nerve or hair stem cells), stem cells transplanted from other people, fetal stem cells, amniotic stem cells, and stem cells made by reprogramming ordinary cells. But I am mainly not concerned with those here.
The technology of harvesting stem cells from bone marrow is well worked out. The challenge is to re-introduce the cells in the right place under the right conditions so that they produce the intended results. Whether stem cells differentiate and what cells stem cells differentiate into depends very much on local inter-cellular signaling and in most cases that signaling is not well understood. Here is a sampling of scattered items intended to give a flavor of what is happening:
· A few “classical” stem cell therapies based on using other people’s cells are in routine use today, such as for treatment of leukemia(ref).
· The FDA apparently wants to subject new stem cell therapies to the same approval procedures required of new drugs. This means they must pass through a controlled bureaucratic process that is likely to cost tens or hundreds of millions of dollars and require seven to ten years of clinical trials for completion.
· A group of US doctorsis challenging that position(ref). They claim that introducing a patient’s own cells back into the body is very different than introducing a foreign drug substance. Accusations have been made that the FDA is killing approval of stem cell therapies by slowing down autologous stem cell transplants and therefore killing patients(ref). How this will play out on the political and medical stages is difficult to predict.
· Private clinics and hospitals have set up stem cell therapy shops in other countries where regulations permit. This article in Forbes outlines overseas stem cell treatment options for Parkinson’s Disease, Alzheimer’s Disease, Multiple Sclerosis, Cardiovascular Disease, and Diabetes in countries such as China, Costa Rica, Ukraine, Republic of Georgia, Russia, India, Germany, Israel, Mexico, Thailand, Argentina, Panama, Singapore, the Dominican Republic and countries in Eastern Europe. Costs typically range from $10,000 to $35,000. An example of a private stem cell clinic is the Xell Center in Germany. Xell only does autologous transplants, offers treatments for a variety of conditions, and claims there is no associated tumor risk.
· Pet and animal stem cell therapy is starting to thrive. Treating dogs for arthritis and horses for orthopedic injuries seem to be favorites.(ref)(ref).
· A small Phase II European study suggests that autologous stem cell therapy is effective in treating congestive heart disease(ref).
· NIH has launched a study of hematopoietic stem cell transplantation for severe, treatment-resistant lupus(ref). This approach may show promise for this formerly intractable disease. The idea is to reboot one’s immune system(ref).
· One branch of autologous stem cell therapy research involves genetically modifying the stem cells before they are re-inserted. See the recent post on this blog Trojan horse stem cells might offer an important new cancer therapy. Stem cell transplants can be used to transfer new genes into patients, for example to protect them from some of the negative effects of chemotherapy treatments(ref).
· Based on work with 9 patients, it appears that autologous Mesenchymal stem cells might be employed as part of a process to cure painful chronic fingertip ulcers experienced by many patients with scleroderma(ref). A cultured stem cell mixture is externally applied to the would along with bioengineered skin.
· A search of the website ClinicalTrials.gov using the search term stem cells retrieved 2572 studies, a few completed, some ongoing and many now recruiting. Of course not all of these involve use of autologous cells. The disease conditions addressed cover nearly every area of medicine.
· Reports of failures and in some cases deaths resulting from stem cell therapies continue to create doubts about them in the minds of many medical professionals. For example, in one case of using human fetal stem cells, brain and spine tumors emerged(ref). Some researchers feel the risks of such things happening are less when autologous transplants used. Also, stem cell clinical trials have been discontinued for safety reasons. Just a few days ago, Aastrom Biosciences Inc. suspended a clinical trial after received a report that a patient died some time after treatment with autologous stem cells for congestive heart failure. It is not known whether the patient’s death is related to the treatment(ref). The FDA is placing the trial on hold pending an investigation.
If all of this leaves you a bit unclear about where things really are, please be comforted by knowing that I am unclear too. I was that way back in 1969 when I was trying to keep up with developments in the computer field. So, perhaps the situation is not so bad. It can only bring good news for longevity.
