Regenerative medicine is the process of creating living, functional tissues to replace or repair tissue or organs that are damaged. This is a relatively new process and can promote rejuvenation in previously irreparable organs. The process begins by taking adult stem cells from a damaged organ or tissue sample, and combining them with an organic structure so the cells may replicate the organ or tissue that they originated from.
Each cell has its own chemical make-up which will predetermine its eventual fate – thus a stem cell from a liver will begin the foundations for a new liver, whilst skin stem cells will grow to produce more skin. Regenerative medicine is key to the advancement of emergency medical procedures and the eventual eradication of chronic organ diseases. Organ and tissue transplantation has come a long way since the first confirmed successful kidney transplant in 1954. Since then, doctors have been able to transplant a wide array of organs including hearts, livers, pancreases, and lungs as well as live donor lung and liver transplants.
In Australia at any given time there are at least 1700 people on the Australian organ transplant waiting list, and the average wait for a transplant can be up to four years (Donation statistics, 2011). In 2009, 799 Australians received donated organs, although this seems like a high number it still leaves at least 900 people desperately waiting for organs (Organ Donor Register, 2011). Regenerative medicine has the ability to create and replace tissues in the body that have lost their ability to work proficiently due to disease, damage, or age.
With correct implementation, organ donors may not be required in the future and patients will only need their own stem cells to regrow new organs and tissues. This may mean that each person has the potential to self-sufficiently replace their own organs if diseased or damaged. A benefit of being able to produce a new organ using the recipient’s cells is that there would be a much lower risk of transplant rejection. Transplant rejection occurs when a transplanted organ or tissue is rejected by the body of the recipient as the recipient’s body identifies the organ as a foreign bject. The immune system subsequently attempts to destroy the organ, bringing about widespread inflammation and the eventual removal of the organ to ensure that the wellbeing of the patient is not compromised (Transplant Rejection, 2009). This risk would be diminished if the new organ was grown from the recipient’s own stem cells, as their body would recognise markers on the new tissue, and accept the organ as “non-foreign”. The principles behind regenerative medicine are relatively simple.
Stem cells are extracted from the tissue of concern – these cells are then activated using growth factors and grown on an organic matrix or structure until a complete organ is developed. There have been remarkable instances of this procedure’s success – such as the American man, Lee Spievak, who lost the tip of his finger in a toy plane accident. The tissue of his fingertip was severed right down to the bone. In Mr Spievak’s case, the lining of a pig’s bladder was used to derive an extracellular matrix to form the basis of his new finger.
By cleaning the lining of the pig’s bladder (using acid) and dehydrating the resultant tissue, a powder was obtained which contained the signals required for constructive remodelling, without the stimuli for scar tissue formation. This powder could then be placed on his wounded area and support the growth of new functional tissue, instead of scarring (The Man Who Grew Back His Finger Tip, 2008). This technique may be utilised slightly differently to replace a complete organ by adding the individual’s own cells to extracellular matrix obtained from pig sources.
The cells react to the matrix and reproduce just like a growing embryo develops organs and tissue. Once structure growth is complete the organ can replace the patient’s damaged or diseased organ without fear of rejections (as the entire organ is made up wholly of the patient’s cells). A recent innovation of regenerative medicine is aimed at burn victims. Patients with severe burn scars are more susceptible to disease and infection; therefore all scars should be covered as quickly as possible.
If left untreated the resultant scarring can be horrific and painful and current treatment can consist of skin grafts that can take months to heal. “Spray-on skin” is an innovation which applies skin cells to the wound to promote healing of the injured area. This is made possible through the collection of a patient’s healthy skin stem cells and the addition of them to a water based solution. This solution is then placed in a spray gun applicator – “skin-cell gun” – and the solution is sprayed over the patients wound.
The wound is then covered with a dressing which promotes growth until fully healed. This technology has been successfully implemented in a number of patients, including one who had extensive second-degree burns to his arm, shoulder, neck and the side of his face. Following the application of this technology, his wounds closed over within four days (Regenerative Medicine, 2011). Regenerative medicine promises enormous potential for further development. Despite being a relatively new method of treatment, regenerative medicine trials have already began in many new fields of medicine.
In Korea a patient who had suffered a spinal cord injury and hadn’t walked in 19 years was able to walk on her own, without difficulty after a suspension of her own stem cells was injected into the damaged part of her spinal cord. Other potential treatments in development include those for brain damage, cancer, heart damage, baldness, blindness, diabetes, and infertility, as well as countless others being trialled around the world. However, there are aspects of regenerative medicine that critics suggest are not yet thoroughly trialled.
As induced regeneration happens faster than normal growth, there is speculation that it may quicken the development of cancer or a induce a cellular chain reaction. These fears sprout from suggestions that there is not enough in-depth understanding of this new technology, and that it is developing quicker than scientific knowledge can keep up (Regenerative Medicines Second Wave, 2010). There is no doubt that the health system currently calls for a better solution for tissue regeneration, and a more reliable alternative to human organ donation.
The field of regenerative medicine provides just this. Not only have the merits of regenerative medicine been shown – in repairing damaged tissues, rebuilding entire organs and providing emergency tissue growth when the patency of the body’s barrier is lost – its potentials are limitless. Further development of this field will be essential to the cure of currently permanent disease states, not limited to: paralysis from spinal cord damage, kidney failure, chronic lung disease and liver failure.