Here are a couple of interesting things that I've come across recently.
The FDA is considering regulating autologous stem cells as prescription drugs. These cells are removed from a patient, multiplied in culture, and then reintroduced at a site of injury. The culture step, reportedly, gets the FDA all in a lather with the desire for control. According to the author of a story at h+ magazine, this could drastically slow down adoption and use, and potentially relegate the the technology to large corporate interests. The story, and an accompanying interview with a physician, argues that self-regulation of stem cell treatments as a medical practice (which the FDA is not chartered to regulate) is a far better choice.
If the FDA does go the route of asserting (or, rather, attempting to assert) its might, it suggests to me that once again the powers that be are not sufficiently in tune with the progress of technology. To wit: here is Attila Chordash's homebrew procedure from MAKE for isolating placental stem cells (I met Attila a few years ago at SciFoo and have participated with him in some IFTF activities -- smart fellow). News this past year has been full of various ways to produce induced pluripotent stem (iPS) cells, ranging from retroviral reprogramming, to drug-controlled lentiviruses, to plasmid-mediated reprogramming. Skin cells were turned into iPSs early in 2008 (here is an earlier summary at Nature Reports Stem Cells). Last November, a paper in PNAS showed a single synthetic prophage containing 4 genes was sufficient to turn a mouse fibroblast into an iPS cell, and showed that the method could be used to generate human iPS cells from human keratinocytes. Each of these steps is said to demonstrate an increase the controllability of the reprogramming, increase the uniformity of the resulting population of cells, and decrease the difficulty.
This is not to say that any step in the reprogramming is simple. From personal experience I can testify that culturing even "stable" human cell lines can be challenging at times. But, by definition, as published methods to reprogram cells are repeated and refined this will demonstrate a progression from iPS cell production as an art into a technology. The plasmid-mediated programming, in particular, strikes me as a promising route to a widespread technology because it does not depend upon, or result in, integration of the plasmid into the host chromosome. Moreover, it will be trivial to synthesize new genes for use in the plasmid as better recipes come along. So how long before these cells will be used in therapies?
A recent review in Science by Gurdon and Melton identifies some interesting challenges:
The future value of reprogrammed cells is of two kinds. One is to create long-lasting cell lines from patients with genetic diseases, in order to test potentially useful drugs or other treatments. The other is to provide replacement cells for patients. To be therapeutically beneficial, replacement cells will probably need (i) to be provided in sufficient numbers; (ii) to carry out their function, even though they are not normally integrated into host tissues; and (iii) to be able to produce the correct amount of their product.There is obviously a great deal of science to do before iPS cells are used on a regular basis to produce therapies. Nonetheless, therapy is already beginning around the world. Medical tourism to China for stem cell treatments is increasingly common, even for children.
A human adult has about 1015 cells, and the liver contains about 1014 cells. To create this number of cells starting from a 10-4 success rate of deriving iPS cells from skin would require an enormous number of cell divisions in culture, although the prolonged culture of ES-like cells provides a valuable amplification step. However, many parts of the human body need a far smaller number of cells to improve function. An example is the human eye retina, in which only 105 cells could be of therapeutic benefit.
Will introduced cells be useful even if not "properly" integrated into the host? Most organs consist of a complex arrangement of several different cell types. The pancreas, for example, contains exocrine (acinar) cells, ductal cells, and at least four kinds of hormone-secreting cells in the endocrine islet. Replacement endocrine cells can provide useful therapeutic benefit even if not incorporated into the normal complex pancreas cell configuration. In some cases, introduced cells can have functionally beneficial effects, even if indirectly. It is not yet clear whether introduced cells will be correctly regulated to produce the desired amount of product.
Clearly, the technology is so promising that families are willing to go to considerable sacrifice to obtain treatment. Which brings us back to the FDA and regulation. I have to wonder what the Feds are thinking. I would certainly agree with anyone who suggests that stem cells are a powerful technology, and that treatments should be safe. But any regulatory or policy step that reduces access and slows progress in the US is simply going to send people overseas for treatment. Then, as the technology becomes ever simpler to learn and use, a back-room market will open up in the States.
So, I wonder, as the technology matures, how long before we get DIYStemCells, Stem_Cells@Home, or HomebrewStemCells? As methods are published to harvest candidate cells and turn them into autologous iPS cells, how long will it be before athletes looking for an edge, the curious, and the truly ill, all start trying this for themselves? I am by no means arguing that this is a good idea, and I strongly suspect that the better course is to ensure that people have access to the technology through physicians who know what they are doing. But without that access, a black market, with all of the shadows and horrors envisioned by William Gibson and others, is inevitable.
Wouldn't it be simpler, and vastly safer, to make sure that everyone has access to skills and materials? This seems like another arena in which pushing for an Open Biology makes a great deal more sense than the alternative.