By Jenny Tang
Organ regeneration is best defined as the regrowth of lost tissues or organs in the response to injury. It is a naturally occurring phenomenon in certain organisms, but in humans only few organs such as the liver and skin are known to be able to redevelop. Through artificial means however, we can generate organs through 3D printing. Although organ generation through 3D printing has potential, there are multiple underlying issues.
The introduction of the concept of bioprinting was initially introduced in 1988 through a modified HP inkjet printer to deposit cells through cytoscribing technology. Cytoscribing is a method for micro positioning cells into predetermined patterns. The different cell adhesion proteins and monoclonal antibodies are deposited under the computers control, subsequently onto a substrate material, which can create two-dimensional tissues.1 Organ printing involves using a conventional 3D printing method where the printer lays down layers of bioplastics until a 3D object is produced which forms a scaffold, that almost acts as a skeleton for the desired organ. The organ cells are transferred onto the scaffold and incubated, allowing the cells to multiply.
The first lab grown bladder was transplanted into dogs successfully, where the bladder cells in the laboratory were seeded into a bladder shaped mold, where they proliferated, which subsequently formed an organ. Usually bladders made out of synthetic material are unsuccessful due to being incompatible with body tissue. This issue was eliminated by using two types of cells from the dog bladders, the smooth muscle cells from the exterior of the bladder and the urothelial cells which line the inside of the bladder.
In 1999, the first human organ created was an artificially engineered human bladder. In Wake Forest University School of Medicine in Winston-Salem, North Carolina, cells from seven children with spina bifida were extracted and used to grow thin sacs of tissue. Researchers used synthetic building blocks to generate a scaffold of a human bladder, which was subsequently coated with human bladder cells, which multiplied to create a new bladder. To avoid rejectionfrom the human body, they utilised the cells taken from the patient.
Currently the only successful organ to be 3D printed and successfully transplanted into a human is the bladder It was made to replace patient Luke Massella’s defective bladder in 2004 and he has not had any complications from the transplant since. The process started when surgeon Anthony Atala at the Boston Children’s Hospital took cells and small slivers of Luke Massella’s bladder. With these samples, Atala was able to grow a new bladder in a laboratory. Atala later had a 14-hour surgical procedure to transplant the new bladder.
Regeneration of organs would help fill the current organ deficit that exists, especially for livers, kidneys, and lungs. Currently, an average of 20 people die daily while waiting for an organ. This issue could potentially be resolved through organ printing, where it only takes 2-3 months to develop an organ. With the benefit of 3D printing being that it uses the patient’s own cells, rather than artificial constructs of cells, rejection is prevented, , which occurs with other human or animal organ donors. The cost to 3D print an organ is substantially lower in comparison to a standard organ transplant. For example, it was estimated that a standard kidney transplant on average costs $300,000 while a 3D bioprinter and the material to print 3D organs can cost as little as $10,000.2The costs are estimated to drop as technology continues to advance. Although there are multiple issues with 3-D printing organs 3.. Firstly, being able to create the vasculature and for the blood flow of the organ to be able to function with it throughout, especially small capillaries. Secondly the precision to print more complex organ structures, such as the urethra, lungs and kidneys with more cells per centimetres, in comparison to the bladder. Flat structures are easier to print in comparison, although still requires careful precision.4 The complex geometry fares as a challenge for 3-D printing organs, and is an area where developments, and further research must be conducted before it is feasible to make 3D organ printing common.
References:
[1] KLEBE, R. (1988). Cytoscribing: A method for micropositioning cells and the construction of two- and three-dimensional synthetic tissues. Experimental Cell Research, 179(2), pp.362–373.
[2] Alexander, D. (2020). The Science Fiction World of 3D Printed Organs. [online] interestingengineering.com. Available at: https://interestingengineering.com/the-science-fiction-world-of-3d-printed-organs.
[3] www.thefreelibrary.com. (n.d.). Lab-grown bladders prove a success in dogs. – Free Online Library. [online] Available at: https://www.thefreelibrary.com/Lab-grown+bladders+prove+a+success+in+dogs-a053984909 [Accessed 27 Jan. 2022].
[4] pitjournal.unc.edu. (n.d.). Regenerative Medicine: The Interplay of Stem Cells and Polymer Science | The People, Ideas, and Things (PIT) Journal. [online] Available at: https://pitjournal.unc.edu/article/regenerative-medicine-interplay-stem-cells-and-polymer-science [Accessed 27 Jan. 2022].
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