The Powers of Regenerative Medicine
"Gentlemen, we can rebuild him. We have the technology."
~Oscar Goldman, a character from "The Six Million Dollar Man"
Times may have finally caught up with the imaginations that created this campy 1970s television show. I have talked previously about how the great strides being made in bionics are giving hope to the blind and movement to paraplegics and amputees, but now we are also having success regenerating human tissue and animal organs.
The field of regenerative medicine is booming, and that has the potential to create advancements most of us would never have even thought possible. One such innovation is extracellular matrix, a powder derived from pig bladders. Normally put to use in repairing tendons during surgery, some scientists have begun to experiment outside the box because it has been found to regenerate tissue. One case in point: extracellular matrix was recently used to re-grow the half-inch end of a person's finger that had been sliced off in an accident. The tip of the finger grew back -- nail, circulation, and all -- without so much as a scar in just four weeks.
Even the scientists who are working with this material, such as the doctors at the University of Pittsburgh Center for Regenerative Medicine, are not sure exactly how it works. It seems to stimulate some of the adult stem cells that function to maintain and repair damaged tissue. Further work with extracellular matrix is due to commence soon, as the United States Army has allied with the University of Pittsburgh in an attempt to re-grow amputated digits of war veterans. If they are successful, who knows what could be next? New arms or legs for those with injuries -- eliminating the need for prosthetics -- might not be too far off on the horizon.
There are a number of different studies currently taking place already to expand the options for regeneration. Scientists in Germany are working on ways to heal serious burns using a regenerative spray to activate new skin growth and possibly replace painful surgeries and skin grafts. In the United States, researchers are experimenting with implanting extracellular matrix into the esophagi of throat cancer patients to stimulate the growth of healthy tissue.
Other trials are focusing on repairing hearts. Regenerating heart muscle tissue harmed by heart attacks or arteries weakened by unchecked high blood pressure and plaque buildup are areas under exploration. There are also incredible animal studies taking place that focus on heart regeneration. In one, taking place at the University of Texas Southwestern Medical Center in Dallas, newborn mice with 15 percent of their hearts removed were able to repair the entire heart in 99 percent of cases with absolutely no regenerative materials used.1
The mice were only able to repair their hearts if the scientists removed the section within the first week after their birth. But when they cut into the mice hearts the day after they were born, the hearts were fully repaired three weeks later. Up until this research, it was believed that mammals could only regenerate heart tissue as embryos. Fish and amphibians are the only animals previously known to possess the ability to regenerate heart tissue, and they can do it throughout their lives.
The mice cells that were activated when the hearts repaired themselves were not stem cells, as some researchers initially guessed, but already differentiated heart cells. Next, scientists have to determine whether this works the same way in newborn human hearts and if so, how to isolate and engage the process so we can turn it on when it's needed.
We may also be able to learn about regeneration by further studying the liver. It is the only organ in the body of which you can destroy up to 80 percent and still have no demonstrative symptoms. It can also regenerate itself in a matter of weeks. Once regenerated, it will fill the same space it occupied before, and will take roughly the same shape as before. After a trauma such as a car accident that has injured part of the liver, the damaged tissue can be removed by the surgeon with no loss of liver function. In a matter of weeks, the liver will have regenerated all of its lost tissue.
If we can find a way to apply that ability to other tissues and organs of the body, surgery may eventually become a tale we tell our grandchildren stories about! If only Luke Skywalker's doctors had known about this when Darth Vader cut off his hand, they could have just re-grown it rather than attach a bionic version -- unless his insurance company decided it was cheaper.
1 Porrello, Enzo R.; Mahmoud, Ahmed I.; Simpson, Emma; Hill, Joseph A.; Richardson, James A.; Olson, Eric N.; Sadek, Hesham A. "Transient Regenerative Potential of the Neonatal Mouse Heart." Science. 25 February 2011. American Association for the Advancement of Science. 5 May 2011. <http://www.sciencemag.org/content/331/6020/1078.abstract?sid=f4187940-c40a-4249-ba27-7aeb62ce735b>.