I'd be surprised if you hadn't heard about ACell, or at least about some of their results. Their MatriStem powder has been able to grow back people's missing fingertips. A cut off finger is sprinkled with the pig-derived material every other day, and in a few weeks the missing tip is regrown. It's been everywhere on TV in the last few years including the Oprah Winfrey Show with Dr. Oz and 60 Minutes. That's actually been a bad thing. People have dismissed these results because of the natural healing of fingertips. Well, ACell's technology can do a lot more than just give you the finger. We've got videos and photos below to explain how this form of regenerative medicine is poised to make a big difference in surgery.
ACell isn't the only name in the pig-derived matrix game. Cook Biotech, who we've discussed before has a somewhat similar line of products that have been used to promote rapid healing after surgery. What are they selling? Acellular, or extracellular matrix (ECM), which is like a scaffolding for the cells in your body. Pigs and people systems are close enough that ECM taken from the porkers can be processed and reformed into sheets or powders compatible with humans. When placed on a surface wound, or used to connect a gap in internal tissue, the ECM serves as a medium upon which your body's cells can grow. As your body grows upon the scaffold, it is slowly absorbed and metabolized into the body. This allows for faster healing and the generation of normal tissue where the wound used to be. It is likely (as experiments in mice have shown) that the ECM is actually attracting stem cells from your marrow to itself and that these stem cells are at least partially responsible for the rapid, more complete healing associated with the technology.
The media has typically focused on a few anecdotal cases of impressive healing associated with the technology. I think Oprah's a great example of this approach to the topic:
So, yeah. People have regrown fingertips using a powdered form of ACell's MatriStem ECM product. The first such case was Lee Spievack, brother to Alan who was one of the original scientific minds behind ACell's founding (he has since passed away). Others include Mike Christensen, from Nebraska, who regrew a 16mm portion of his left thumb. While Spievack received his treatment for free, Christensen paid about $1200 for his powdered MatriStem which was prescribed and applied by a doctor. "$1200 for a new thumb", you say, "sign me up!" But that's kind of the problem.
ACell has been called quack science and other derivative names in the press because of the sensationalized cases of these fingertip stories. Its critics point out that fingertips sometimes will regrow on their own. Not completely. Not 16mm perhaps, but a good percentage of that, especially among the very young. "This isn't miracle science", they say, "it's a natural healing process." It doesn't help that most television programs that discuss the technology get hyperbolic very quickly. We can heal any wound! We'll be able to regrow your limbs! We'll turn you into a lizard! No, no, and weird.
Luckily, we can throw away all the anecdotal and controversial evidence for finger regeneration. We don't need it. ECM technology has many more applications and many more successes to support its claims. It has been shown to be effective in surgeries involving the heart, esophagus, hernia, surface injuries, bladder, orthopedics, and ear drum. It has helped humans heal fissures in skin, ligament, and muscle tissues. Steven Badylak, a researcher in regenerative medicine at the University of Pittsburgh, gave a great overview of acellular/extracellular matrices back in 2008 at Pop Tech. Skip to -14:15 to get to the good stuff, and watch out for the obligatory fingertip mention at -5:10.
I must admit that I have been very cautious about believing in ACell's technology. In fact, I may have yelled disparaging words at my TV when I first saw it appear on daytime television. The idea of a powder regrowing limbs seemed like pure science fiction.
Now, my opinion about the technology is much closer to 'begrudgingly optimistic'. Anthony Atala, a name in regenerative medicine I have come to respect, is one of the members of ACell's scientific board. The MatriStem product (in both sheets and powders) is FDA approved for surgical and topical uses. The list of ACell publications continues to grow, with many peer-reviewed-journal articles. Their veterinary applications (horses especially) are also well researched and reviewed. Yes there's a lot of idiotic hype on the web about this technology, and I don't want to be associated with it, but I can't ignore that ECM has been shown to be 'good science'.
It seems that MatriStem, or some other ECM product from ACell or Cook Biotech or their competitors, is going to start becoming a more widely used tool in surgery. But it will be just one of many. We've seen different regenerative medicine technologies lately that are likely to fit together or work in different tiers. Skin printing and ECMs may help with surface injuries. ECMs will assist with surgeries for injured internal organs. Organ printing or stem cells on collagen scaffolds will allow us to replace organs that cannot be healed. Some form of advanced transplants may be able to replace large portions of our missing bodies (including faces and hands). Minor regeneration of missing parts could be accomplished via ECM, protein treatments to affect stem cell activation, and other techniques. When regenerative medicine as a field finally breaks through into standard medical practice, we'll have all these options and more. The next generation in healing is near.
[image credits: Alyssa Schukar/The World Herald, ACell]