Looking over the announcements from stem cell research, it seems that finding sources of stem cells might not be much of a problem, now and certainly in the future. What started with a single – highly controversial – source, embryonic stem cells, is burgeoning into stem cells from bones, muscles, skin, liver, brain, blood (etc.)…and now urine.
Yes, this is another of those ‘weird science’ type stories that some media are fond of promoting. Yet, it is also a story that is based in what scientists actually managed to do, and it’s also representative of (arguably) the two biggest trends in stem cell research: Finding stem cells in novel locations, and using stem cells as treatment for a rapidly increasing range of applications.
The first trend is, of course, finding and utilizing stem cells from a remarkable variety of organs and bodily substances. It’s really important at this point to understanding that “finding stem cells” is a nice catch-all term, but it’s not very accurate. Most of the stem cells discovered in various organs are, in fact, specific to that organ; they are not generic stem cells (although sometimes they can be modified). Also, in their native form most of these newly discovered stem cells are not pluripotent (can be any type of cell, except eggs or sperm) much less totipotent (can become any kind of cell). Some of them are multipotent, which in no way denigrates their usefulness, and others are unipotent (often called progenitor cells because they can only make one kind of cell).
That does not mean these (more or less) organ specific stem cells are of little use, or even that they can’t be manipulated into becoming useful outside their ‘base organ.’ Stem cells in urine are a good example.
The research done by Wake Forest Baptist Medical Center’s Institute for Regenerative Medicine started with developing a technique for extracting stem cells from urine. That stem cells were present in urine – in a sense, as detritus scraped from the kidneys, bladder and even the bloodstream – was known from some time, although their exact origin is still unknown. The technique involves a form of physical-chemical filtering, as there are scores of cell types in urine. Once detected, the urine stem cells are collected – sounds simple, but it’s not.
What’s important is that, for obvious reasons, this is a readily available supply of stem cells. Better yet, they can be collected from an individual, which is always preferred for treatment because it reduces the risk of that person’s immune system rejecting the cells. Obviously, this source of stem cells is also free of the embryonic stem cell controversy.
While the source of urine stem cells may seem a little odd (which, of course, it’s not), the cells themselves are multipotent, meaning that while they can’t be turned into every other kind of cell, they can do more than produce more urinary tract cells.
But for the moment, let’s focus on just the urinary tract use of these stem cells, because it’s the most realistic use (at least in the short term) and because there is a lot these cells can potentially do for medicine and health in that one area alone.
During initial testing, the research team found that urine stem cells could successfully generate the three main kinds of tissue layers (endoderm, ectoderm and mesoderm), which is the hallmark of a true stem cell. They were able to use the cells to create bladder related cells such as bladder muscle and the lining of the bladder. From this, they concluded that the cells could easily be turned into other urinary tract related cells reaching from the kidneys, bladder, urethra and tissues such as within the penis.
The use of stem cells as “treatment” is at once an exciting and horribly over-hyped subject. Whether all types of stem cells can be usefully injected (or otherwise delivered) into an appropriate area to “repair” tissue, or even more radically to create (in vitro) new tissue or organs, remains an open and long-term question. Still, there is an avalanche of stem cell applications – some legitimate, some not – all claiming that such-and-such stem cell did repair or heal or support (words to that effect) tissue damage or disease.
As yet, organ tissue created from urine-related stem cells has not had testing for treatment application, although that will be along in the next few years. The researchers believe that it has a strong potential, not only for generating urinary tract repair, but also for use in modified form for such diverse applications as forming bone, cartilage, fat, skeletal muscle, nerve, and endothelial cells, which line blood vessels.
There is an added bonus. Unlike many other pluripotent cells (especially induced pluripotent cells, i.e. artificially stimulated), multipotent urine-related cells do not appear to have the high risk of developing tumors.
There you have it. While some may snigger (“What a piss-poor way to get stem cells!”), the end result is actually superior, at least for some applications. It will be years before the potential of urine-related stem cells is verified, but it very much looks like this humble source of stem cells will join the list of the practical and plentiful.
