Dr. Jordan S. Miller is a postdoctoral colleague at the University of Pennsylvania in Dr. Christopher S. Chen’s Tissue Microfabrication Laboratory in the Department of Bioengineering. He is also a board member of Hive76. Before his time at Penn, he was a developer at RepRap and an associate at PTV Sciences. Dr. Miller received a PhD from Rice University and earned his undergraduate degree from MIT.
We had the pleasure of interviewing Dr. Miller over Skype this month to discuss some questions we had about bioprinting and it’s progress. Here is what we found out!
Q: How does an organ bridge/connect to the new host in regards to normal transplant?
A: In normal cases, a donors organ that is separate from the patients own organs, has an artery and veins. Doctors connect as many vascular connections as they can make. To “bridge” the organ to the patient, surgeons attach the corresponding artery and veinsin the patient to the artery and veins in the donated organ.
Q: With the technology to print/renew our organs, do you think it will prolong the life of human by a significant amount by simply replacing the part that has been worn out?
A: A regular transplant would prolong life for a very long time, much better and for longer than using an anything made in the lab. Lab-generated organs cannot be fully considered as organs, exactly. Because of this they are called organoids. Complexities made in lab are much less sophisticated as the ones naturally found in the body.
For example, for the liver there are several dozen types of cells, and all perform a different type of function. The livers that we are making now in the lab only have about one or two cell types in them. Nowhere near the complexity naturally found in the body. Short term prolongation of life is possible in the perceivable future;however, not actually used to perform as permanent organs and replacing organ donors fully, but could be used for the short term until an organ donor is available.
Q: Could it possibly be used for just repairing a part of an organ?
A: Yes it can for sure be used to do that as well.
Q: What is the shelf life for engineered organs; what means are required to sustain them?
A: Normally, we first take a sample of the patient’s own cells and from that actually make more cells in lab. To do that, flat Petri dishes are used. We then make a scaffold, a material that is used to form the shape of the desired organ or vein. Typically it has been thin organs (ex, skin, cornea or bladder) so it is a thin layer of material made by people in the lab and on that material they place the patients cells. The cells than begin to grow and in a way, evade (?) that material. If fully and successfully evaded, can be placed into the patient. When the cells have finished adhering to the material, the shelf life is probably only a few days; you would want to implant the organ into the body right away.
Q: How long does it take to get an engineered organ to mature and what are the challenges?
A: Depends on the tissue type and organ type. For example, the cornea would take a couple of days and for others, it would take a week to grow enough cells for the specialized tissue. So it all depends on the scale of the organ, and also how much source material you can have. If you can only take a small biopsy from the patient than you wont be able to grow up a lot of cells quickly, but if you’re able to take a larger biopsy you would be able to grow more cells quicker.
Q: Approximately how many cells are required for bones and organ printing?
A: One or two cell types, but we’re able to create millions of cells in lab to create organs. The ability to create multiple cell types to perform all the same functions in natural tissues has not yet been reached. Generally most tissues and organs have multiple cell types; some cells make up the vascular cells, so all the blood vessels are all one type of cell, and they for the most part can make capillaries on their own. People know how to do that in lab, in organs they each have their own active type of cell, so in the kidney there be kidney cells, and liver there would be liver cells and so on. These cells are the main ones performing the specialized function, so that is then facilitated by the cells that make up the blood vessels and these are the cells that are laid down on the lab created material. They are kind of protein cells types, called fibroblasts, that make up a majority of the physical component of the organs and tissues. For bones, there are cells that make up the calcium enriched bone deposits, and others that take it away. So, there is interplay between those two cell types. For other organs there are immune cells that are always on patrol for injury and infection.
Q: Are we not able to make certain type of cells yet, for example the immune cells?
A: We can’t make those in lab, so the idea is to actually implant the organ and have the patients own immune cells migrate back in if the organ is not initially rejected. We don’t fully understand these cells, theoretically if we knew everything cells had to do, we could recreate that and have multiple cell types but we just still don’t know how to do that at the moment.
Q: How is the testing the process done, to test how natural cells, for example immune cells, transfer to the lab generated organ? Would you be using animals?
A: What we have been doing has only been done in the lab, so done in vitro. We can grow up cells and put them in structures, and we’re working towards larger structures. So right now they are 1 cm on each side, made into a cube and we can actually measure how well the cells are surviving in the structure and measure how well the cells are doing in this structure, in an environment that cells are not normally in. So an example is we put liver cells in this cube, that have blood vessel structure that we made, and we measure the proteins and chemicals livers cell normally make, one is called albumin, and biotin.
Then after you do in vitro, during the process of making it so implants can be done with humans, you have to do implants in animals and see how those cells perform in that type of environment.
Q: What are your thoughts about this technology in regards to ethics?
A: In regards to animal testing that has always been an ethical issue in various medical fields and with also the general public. It is up to the scientist and interaction with their communities, and also the legality of it depending on what country you live in or what state. Also the ethics surrounding it that are taught in school, especially bio ethics research.
If we didn’t have to do animal studies it would be ideal, but even people who do not favor animal studies wouldn’t recommend going directly from in vitro to directly testing on humans.
What is exciting is people are learning more and more about how to grow human cells outside of the human body. So potentially you can make large structure of organs, you can test cells on these lab generated organs instead of animal testing.
Q: We also have learned that there is research on generating organs so drugs can be tested on them.
A: Yes, there is a lot of support for that area especially from pharmaceutical companies. With enough financial support, it can break through a lot of barriers and large-scale investigations can be done.
Q: How far are we from the actual use of organs for transplants?
A: There are humans living today with tissues and organs created in lab. For example with skin, cornea and the bladder. Last year, a tricera was down, so the wind pipe, so again thin tissue organs that are easily architected are available. But more complex organs it will most likely be another 30 years before those transplants are available.
Q: Will bioprinting be affordable for the average person?
A: These things always start off at low volume, even if they are wildly successful it always begins with a low population, over time the technology will become more standardized and commoditized and come off patent. When that happens it becomes available to a very large audience so, think like drugs that are over the counter now used to be only available through prescription. Not that organs will be available over the counter, but when you think about antibiotics that are prescribed, anyone can get prescribed anti biotics from their doctors. Hopefully down the road in our lifetime if a doctor determines you need a new organ he can just take a tissue sample from you and that can be used to create a new organ to be implanted maybe two months after that is made from your own cells.
We do want to see it more widespread because there are more and more people who need organs and there are not enough available organs.
We are so appreciative that we had the chance to interview an industry expert! It was very exciting to speak with Dr. Jordan Miller and hear his insights on bioprinting. We were also given the opportunity to speak with another expert in the field recently so remember to keep on coming back every Thursday to gain more insight on the evolution of bioprinting!
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