If you think that creating body parts in the laboratory is the stuff of science fiction, think again, because the field of regenerative medicine has made the synthesis of human tissue an exciting reality, and the implications for organ transplantation, not to mention for medicine as a whole, are enormous.
Regeneration is a process that utilizes the body’s own cells and machinery to replace lost or damaged tissue. Under ordinary circumstances, when we are injured, cell death occurs at the damaged site, which in turn alerts the immune system that there is a problem. The body’s “immune response” is to send in white blood cells to clean things up while the body repairs the damage. The ensuing scar tissue heals the wound, but prevents any further cell growth from occurring.
With regenerative medicine, by employing a structural element that every living animal has, doctors have been able to halt the scarring process and instead coax the body into restoring the tissue and thus replace what has been lost through injury or disease. That structural element in question is known as extra-cellular matrix, or ECM.
ECM is made up of proteins and some complex sugars, or polysaccharides, and is often referred to as a type of “scaffolding” to which cells are bound. In other words, the cells in our body aren’t just floating around inside of us, something holds them together (with the exception of blood, of course), and that something is the ECM.
At one time it was believed that the ECM had simply a structural purpose to hold the cells in place, but it is now known that it plays a much larger role, influencing such things as cell form, development, and function. In fact, when we are in the womb, the ECM interacts with stem cells to direct the development of the human body, though it is believed that once the fetus is fully developed, the ECM ceases to operate in this capacity.
However, with the addition of “external” ECM, which is often derived from pigs, doctors are hoping that the seemingly dormant ECM can be awakened into activity, and in fact, that appears to be exactly what can happen, as seen in the flesh, no pun intended, on a recent episode of Oprah.
In the story in question, Lee Spievack, a hobby store owner, accidentally sliced off the tip of his finger, and had the misfortune of misplacing the severed piece. Under normal circumstances, he would have been resigned to a skin graft followed by a life with a compromised digit and some scar tissue, but these were not ordinary circumstances.
It turns out that his brother was Dr. Alan Spievack, a doctor and a pioneer in the field of regenerative medicine. He gave Lee some powdered ECM extract to put on his injury, and after about four weeks, the digit actually grew back, fingernail and all. It is instructive to note that the patient did not lose his entire finger, but just a piece of it.
What happened is the pig-derived ECM signaled the body to stop the immune response and instead begin the process of replacing the lost tissue, much like what occurs in a fetus, except that it happened in an adult body. What’s truly amazing is that doctors are able to replicate what happened on the man’s fingertip in the laboratory.
Using the fact that the cells necessary to regenerate already exist in our tissue, they just need to properly “encouraged” to begin the regenerative process, Dr. Anthony Atala and his laboratory at Wake Forest University are growing everything from muscle tissue to complete organs from a patient’s stem cells. Furthermore, using Dr. Atala’s technique, doctors in Philadelphia have actually succeeded in transplanting laboratory grown bladders that were created from the patients own cells.
The significance of these breakthroughs cannot be overstated. The ability to generate healthy organs outside the body gets around the current problem of long transplant waiting lists, and because the organs are derived from the patient’s own tissue, it eliminates the possibility of organ rejection, not to mention the need for complicated immunosuppressive regimens that have potentially dangerous side effects.
In lieu of all this, it may be fair to say that the field of medicine will never be the same, and supports the idea that stem cell technology will play a significant role in the cutting edge techniques that will improve the health and well-being of people the world over.