Transplantation has developed in leaps and bounds in the replacement of severely damaged organs. However increased longevity and harmful lifestyles, such as smoking and excessive alcohol consumption, have caused a dramatic increase in the demand for organs. The transplantation system has reached crisis levels, with only a third of those on the kidney transplant waiting list receiving a transplant between April 2012 and April 2013 in the UK.
Recent advances in cell biology have allowed for the culturing of human cell lines in laboratories. This simple culturing has already been very useful and is used regularly to grow skin. But these cells usually lack more complex structure and cannot grow new organs. Other technologies to grow organs are being developed, using collagen scaffolds as a surface.
But using a 3D printer may be the way forward. 3D printing is the process of using a printer to print out complex structures from various materials, including biologically safe plastics, biochemicals and living cells, to form mechanically and biologically functional structures for use in regenerative treatments.
The 3D printers can be used to print out structures similar to the collagen scaffold which can then be impregnated with cells. The materials used are medically safe and long-lasting. Last year in the US a two year old girl who was born without a trachea received a plastic windpipe developed by this method and coated with her own stem cells. Unfortunately, she died as a result of lung complications following the surgery despite the trachea being fully functional.
Anthony Atala at Wake Forrest School of Medicine is one of the leading pioneers of these technologies and has used 3D printers which print out cells along with collagen and a coagulant to build up an organ one layer at a time. The Atala lab has been running a clinical trial using the bladders made by this method. In his 2011 TED talk he also showed that a kidney could be printed out in just seven hours! This remarkable speed is very promising allowing rapid treatment for patients who undergo severe organ trauma.
Until recently the organs developed had to be relatively simple because of difficulties in printing capillaries, the small blood vessels which supply oxygen to cells. A break through by researchers at Sydney and Harvard last year showed that it was possible to print these, suggesting that more complex and longer-lasting organs may not be too far away.
In addition to work on printed organs, researchers at Wake Forrest School of Medicine are attempting to develop medical machinery for in situ printing, which prints cells directly onto the patient to correct damage. In mice this treatment can halve the time taken for the skin to heal, and whilst it is still in pre-clinical stages, it shows a great deal of promise.
Tissue engineering and 3D printing of whole organs are showing immense promise. They clearly have the potential to revolutionise modern medicine and they will help to address the global transplant shortage, combating the patient–organ rejection problem which has plagued the field of transplantation since its inception.