What would the world be like if we could regrow a finger or a toe? What if we could regrow a heart or a liver to replace a damaged one? If regrowing body parts is possible, there will be no need for an organ donor list, prosthetics, rehabilitation, or different medications.
The advance science of regeneration
Researchers are finding ways to turn dreams of regrowing body parts into reality. Regrowing body parts is a fast moving field that is known as regenerative medicine. It promises to replace damaged and diseased tissues and organs. Many researchers that have been conducting studies on regenerating cell tissues on animals are now conducting it on humans, with hopes that their research will be successful.
In the mid-1980s, Ken Muneoka, a professor at Tulane University in New Orleans, Louisiana, has been identifying genes that regulate the growth of digits in mice. Muneoka discovered that young mice can regenerate a toe. He continued to study mice toes with the hopes of discovering if similar regenerative mechanisms exist in grown humans. In 2010, Munoka's lab showed the possibility of enhancing the regenerative response of a toe in adult. "Ultimately I think we are going to able to regenerate a mouse digit and a mouse limb. If we can regenerate a digit, we should be able to regenerate hearts and muscle," said Muneoka
In another study, Ken Poss, a cell biologist at Duke University in Durham, North Carolina, and his colleagues demonstrated that a zebra fish has the ability to repair a damaged heart from protein.
At the University of Illinois at Urbana-Champaign, researchers in the cell and development biology department studied headless worms and they reprogrammed the worms to regrow a new head.
Is it possible for humans?
Can regenerative properties be applied to humans? Some researchers are skeptical and are cautious to predict. Other researchers think it is not only possible, it will be a reality in ten years from now. "Fifteen years ago we would have said fifty years, but it could be as soon as ten years now," said Poss.
Many are not aware that humans have regenerative abilities. Our bodies are continually rebuilding themselves at the cellular level to fix damage and heal wounds. In addition, young children can occasionally regrow a fingertip or a tip of a toe, given that it's been amputated. Adults can regenerate a portion of his or her liver once damaged.
Researchers were able to regenerate human's cell tissues but only in a lab through stem cells. Stem cells in a bone marrow can create fresh blood cells and stem cells in the skin that can grow scar tissues to seal a wound.
Researchers from the Gladstone Institutes, at the University of California, San Francisco, turned human scar tissue into electrically conductive tissue resembling beating heart cells, in a lab dish by rearranging a few key genes. It was previously conducted in mice that were damaged by heart attacks; they are predicting it could help humans who have suffered from heart attacks.
Professor Alicia El Haj, director of the institute for science and technology in medicine at Keele University in Newscatle, United Kingdom, is working on repairing broken bones and damaged cartilage. El Haj and her team developed an injectable gel containing stem cells that have tiny magnetic particles attached to their surface. When stimulating the area with a magnetic field, they can replicate the mechanical force to allow the bones to grow denser. El Haj hopes to start trails in patients within the next five years.
Researchers is Canada are trying to crack the secrets of regeneration in human bodies. Dr. Ian Rogers at Mount Sinai Hospital in Toronto is working on a replacement pancreas that will grow in a lab and then placed in patients who have Type 1 diabetes to restore their insulin production. At this stage, Rogers and his team is building pancreas out of a surgical sponge, but Rogers admits, making a pancreas is complicated. "Right now our goal is to treat for a year or two," says Rogers.
The only primary organ that was successfully transplanted into a patient is a lab-grown windpipe created from stem cells that grew on a scaffold. The stem cells were taken from the patient's bone marrow and implanted onto a scaffold that was created by striping a donated trachea of its cells. A patient in United Kingdom, who had suffered damage on her trachea following a rare form of tuberculosis, had a three-inch long lab-grown windpipe transplanted. Also, a two-year-old girl received a lab-grown windpipe transplant that was made from plastics fibres and her own stem cells. Unfortunately, she died three months after her operation.
Will it be practical?
If this become a reality, how long will it take to regrow a bone, a pancreas, or an arm? Some skeptics argue that growing a new organ will take several years, and therefore be time-consuming and impractical. David M. Gardiner, professor of developmental and cell biology at the University of California-Irvine, who is a principal investigator in the Limb Regeneration research program, disagree. "You need to structure to regenerate. The fibroblasts – a type of cell that forms the framework for tissue – makes the blueprint. I think that over the long term we will be able to regenerate, but to do that, we will need to figure out the information grid."
However, saying it will happen is giving people a hopeless dream. "We can envision using the knowledge to promote organs or tissue to grow," Elly Tanaka, who studies regeneration in salamanders at the Max Planck Institute in Germany. "But it is dangerous to say, 'Yes, we expect to regenerate a limb."
Should we continue to study it?
The main question is, "Should we continue studying human regeneration? Would it be functional?" Even though many researchers are optimistic and willing to put in the effort, the issue of funding of the project needs to be considered. Muneoka said future progress is dependent on how much we are willing to spend to make human regeneration become a reality. "It is a commitment issue whether it is possible or not in human," said Muneoka. "Someone has to fund this research"
Moreover, if human regeneration is possible, will it be fully functional? Will afinger live until the death of a human, or will the finger become dysfunctional one day? Right now, there are many unknown factors, and the studies on regenerative properties in animals have not provided much information in that aspect. However, we do know for sure that regenerative medicine is evolving and progress has been made. We will have to wait and see what new discovery will come next.