One thousand people die in the UK every year in need of an organ transplant, as there are simply not enough donors available. The problem was termed “a public health crisis” by Anthony Atala at the March 2011 TED (Technology, Entertainment & Design) conference, as “during the last 10 years, the number of patients requiring transplants has doubled, and at the same time the number of transplants has barely gone up”. However, Atala’s own research team at the Wake Forest Institute for Regenerative Medicine (WFIRM) is providing hope. They are developing ‘bio-printers’; 3D printers which can ‘print’ organs.
A prototype kidney was presented to the audience at the 2011 TED conference, which took a mere seven hours to print. Although these prototype kidneys are many years away from being applied in clinical use, it is a significant achievement considering 90 per cent of patients on transplant lists are waiting for a kidney.
The idea of a 3D printer is to create a solid three-dimensional object from a digital file, in an additive process. Conventional 3D printers are used in manufacturing to produce items ranging from jewellery to aeroplane parts. They are similar in structure to ink-jet printers, yet instead of using ink, the machines layer a material, such as plastic or titanium, in successive layers to build a 3D structure. A bio-printer works on the same principle, depositing layers of human cells on top of each other to create a tissue or organ. To ‘plot’ the organ, a CT scan is performed on the patient, which creates a detailed image of the individual layers of the body. The printer can then use the CT scan as a map, producing the required organ.
Atala has said eventually he hopes advanced machines will be able to scan a patient whilst they are in surgery, then ‘print’ healthy tissue onto the required area whilst they are on the operating table. It is difficult to predict when this technology will become mainstream and it must be emphasised there are many challenges to overcome. Solid organs are difficult to produce: the liver, heart and pancreas are the ultimate challenge for regenerative medicine. Despite this, researchers seem optimistic that one day in the future patients may not have to be put on a waiting list for a donated organ, a new one could quickly be ‘printed’. The organ will be tailored to the individual’s body, as the cells can be generated from the patient’s own progenitor cells.
This is a promising future for regenerative medicine, since the body will not reject organs produced in this way, and immunosuppressant drugs are not needed. This gives transplant patients immense freedom when compared to today when they are required to take immunosuppressants for the rest of their lives. Imagine, a patient may be able to have a diagnosis, for example of heart disease, a sample of their cells taken and a new heart grown for them and transplanted within a few days.
The advances in knowledge in regenerative medicine leading to the production of a ‘bio-printer’ have already brought patients benefits. There are two basic elements required to engineer a whole organ: a scaffold and human cells to layer onto the scaffold. We can take cells from an organ’s damaged tissue, less than the size of a postage stamp, and grow them in culture. Then layer a ‘smart bar’ material acting as a scaffold with these cells.
This technique was successfully used in 2008 on Claudia Castillo, whose windpipe had been damaged by tuberculosis. A donor windpipe from a recently deceased patient was washed with strong enzymes, leaving a tissue scaffold, made of fibrous protein. Then cells with Castillo’s damaged windpipe and adult stem cells were then layered onto the tissue scaffold. The windpipe was incubated in a bioreactor for 4 days, and transplanted into the patient; the operation was successful and the patient now leads an active life.
Currently the Wake Forest Institutive for Regenerative Medicine is working to engineer over 30 types of tissue and organ, and although the engineering technology of ‘bioprinting’ will not be ready for some time, recent successes in the field including Claudia Castillo’s prototype have proved that perhaps we can all look forward to a day when transplant waiting lists are a thing of the past.