Food for thought: a future with synthetic organs

Ever seen the 2010 flick, Repo Men? Don’t. Unless you’re really into gratuitous displays of raw human flesh (exposed while the subject is alive and conscious!), then this sci-fi/action movie—about a future in which artificial organs can be purchased on credit—isn’t for you. But I'm not blogging a film review. The movie is simply a dramatization and pessimistic distortion of what could be a new reality on the horizon.

Last week, the New York Times reported on an exciting operation that took place in November. A thirty-year-old Maryland man with inoperable tracheal cancer received a synthetic windpipe, the second operation of its kind and the first on an American. CT scans of the patient’s existing trachea were used to create a synthetic one from nanofibers of the same plastic found in pop bottles. This scaffold was then soaked in a suspension of the patient’s bone marrow stem cells. Once the cells adhered to the scaffold, transcription factors were used to induce the stem cells to differentiate into trachea-specific cells. Using the patient’s own cells eliminated the need for anti-rejection drugs, however California Institute for Regenerative Medicine president Alan O. Trounson insists that some immune response can still be expected. The operation cost $450,000 USD.

Last March, regenerative medicine specialist Anthony Atala wowed his audience at the 2011 TED conference by printing a human kidney on stage using an inkjet printer. Now, the kidney was non-functional; it was a proof a principle that 3D images of a patient’s organ or wound, along with a small tissue sample, can be used to heal the wound or recreate a custom version of the organ. Three quarters of Canadians on organ transplant lists await a kidney, yet donors are sparse. A custom printed kidney would relieve both this organ shortage and the need for dialysis. At the end of his talk, Atala brought a former patient on stage, a healthy college student who, at 10 years old, had received a printed bladder.

…which brings us closer to home: at last week’s downtown MBP seminar, Sanaz Alali from Alex Vitkin’s lab presented her research project on anisotropy detection in normal and obstructed bladder. As a rationale for her project, she cited the use of laboratory-derived bladders that require “priming” — forced stretching of the synthetic bladder to mimic in vivo function — before being transplanted into a human patient.

Some, if not many of these advancements in synthetic organ transplants have been made possible by the wealth of research into stem cells and regenerative medicine over the last several decades, much of which was done right here in Toronto. But as the era of custom-designed organs approaches, biomedicine will face new philosophical, ethical and economic challenges.

Repo Men highlights the first of these: how will synthetic organs be incorporated into our public health care system? Will patients be required to dish out hundreds of thousands of dollars for a Canon-printed kidney, or a pop-bottle trachea? What happens when a patient, unconscious after a car accident, is given a synthetic lung without consenting to the cost? As the movie clearly suggests, you can’t simply repossess a lung as you would a house or a car.

Other issues come to mind. With the exception of inherited organ-specific diseases, most of us can boast equivalent body parts. That is to say, my pancreas isn’t any better than yours. But it seems reasonable to imagine a “quality gradient” in manufactured organs: $250,000 dollars for the 2011 model or $500,000 for the 2012. Could synthetic organs introduce a new platform upon which socioeconomic differences might present themselves?

And finally, what implications would the availability of synthetic organs have for our pre-existing organ donor list, and the medical ethics we use to triage organ recipients? It is a contentious issue whether a patient’s smoking or drinking history should affect his or her rank in line for a donated lung or liver. Many would argue that rewarding the lifetime-non-drinker would provide a cessation incentive for drinkers at risk for liver disease. Now introduce synthetic organs into the picture. By increasing the organ supply, do we remove incentives for cessation of risky behavior?

I am by no means decrying the future of synthetic organ transplant. On the contrary, I worry that it won’t come quickly enough: In 2002, 6,187 Americans on the transplant list died while waiting for an organ—that’s 17 patients each day. At about 14 donors per million people, our national organ donor rate in Canada is less than half that of the top-scoring countries. Widespread availability of synthetic, custom-made organs will no doubt save thousands of lives, but medical ethicists and health policy professionals will have to carefully craft a way of integrating this technology into our existing healthcare framework.

What do you think about the future of synthetic organ engineering?