Question 1: Tell us about yourself. What background do you have, and what projects are you currently working on?

My undergraduate degree was in Chemistry at Carnegie Mellon University. My PhD was in biomedical engineering from Harvard University. I did my PhD research with Bob Langer, and I did a postdoctoral fellowship in developmental biology at NIH. I've been working at Johns Hopkins for the past 18 months.

Question 2: Tell us about your work on stem cells. Is there a basic goal for your research?

The general goal of my laboratory is to rationally design functional tissue. We want to use principals of developmental biology, some basic science, and functional tissue equivalence, in order to derive clinical applications for stem cells, and to develop viable products for patients to use. First we started in the musculoskeletal system in cartilage, and now we are working on bone regeneration. In order to accomplish these things, we use stem cells. Our initial work was using autolygous cells, taking a biopsy from someone's bone marrow, and there is an FDA approved treatment using that hygensime, it is called hard cell. It is currently a first-generation product. From the perspective of minimizing invasive procedures, and getting maximum tissue regeneration, stem cells provide the optimum solution. We are looking at both adult stem cells and embryonic stem cells. We know a little more about adult stem cells, Dr. Cyrus here in Baltimore is looking at potential clinical products using adult stem cells. So adult stem cells seem more promising for near-term products or therapies for bone regeneration. Embryonic stem cells have enormous potential, but we don't know enough about them yet. There is a substantial amount of basic science that needs to be done. Fortunately, many biomaterial systems provide excellent platforms for studying embryonic stem cells.

Question 3: Do stem cells have the capability to differentiate into any type of cell?

There are different types of stem cells. For instance, there are stem cells called multipotents, these cells have the potential to differentiate into many types of tissue, but we don't know yet if they can differentiate into any type of tissue. Then there are totipotent stem cells that can become any type of tissue. It was originally thought that adult stem cells didn't have this capability, but recent research indicates that adult stem cells may indeed accomplish this.

Question 4: What is the difference between embryonic and adult stem cells? Are those the only two types?

Stem cells are generally classified into adult and embryonic stem cells. Adult stem cells are found throughout the human body, in different places. Embryonic stem cells usually come from embryos, from fetus cells. Those embryonic cells can remain undifferentiated for years, if properly frozen. They can replicate and multiply while remaining undifferentiated, they can maintain their genotype and teleomerase.

With adult stem cells, for example the types that we get from bone marrow, they can only go through four replications.

Question 5: How does one harvest stem cells?

For the bone marrow, it is pretty easy. We simply aspirate bone marrow from the Illiac crest. We then take the bone marrow and process it, and select for the cells that adhere to plastic. Usually blood cells will not stick, and eventually die. But people have different techniques for isolating stem cells. Everybody has their own tricks for isolating the purest population of stem cells.

Question 6: What proportions of your stem cells are from human, and what proportions are from animals?

For research, we primarily use animal stem cells, because we can pick the same age, and the quality is more reproducible. In humans, by contrast, there are more variations in age and more general variations. So in our research, we prefer to use stem cells from goats. We have worked with rabbits, and some researchers still use rats. The goat provides a good animal model for the knee joint, so it makes it easier to go from invitro to in vivo experiments. If we used rats, we would have to redo the experiments on goats to make sure that it still worked.

Question 7: I take it that one of the primary areas that you are investigating with stem cells is the knee.

Yes, we are looking at the knee, but there are also people looking at the ankle, and the articulating joints, and the plastic surgeons are interested in subcutaneous tissue augmentation. But these techniques could also be used for cancers, gunshot wounds, wounds caused by mines, and congenital defects.

Question 8: It does seem that your research is potentially disruptive to the conventional medical community. Are you concerned that the more conservative elements within the medical might resist this technology? Are orthopedic surgeons threatened by your work?

Actually, orthopedic surgeons are very excited about this work. They see the need for a cartilage generation product. Many of them are working on this partial procedure, which is a biological treatment, a cell-based therapy. But the problem with this procedure is that it requires two surgeries – the second one is an open surgery, which requires exposure of the knee. As a result, the risk/benefit aspects need to be examined. So our work opens up the potential to greatly increase the number of individuals with knee problems who could be helped. Arthroscopic surgeries will still be needed after this. But the medical community realizes that this is the future, and that current treatments are often ineffective. There currently aren't any effective treatments for cartilage problems.

Question 9: Is there a timeframe for advances? Do you think that stem cell treatments will be standard within the next decade?

There is the issue of when the technology is ready to be used on humans, and then there is FDA approval, and scale up. I would say that we are on the scale of a couple of years.

Question 10: How does your treatment deal with the rejection of tissue?

There is the option to use autologous cells. That has the advantage that rejection isn't a concern, but it can be difficult to harvest those cells. One has to extract the bone marrow that is a costly and laborious procedure. A company here in Baltimore called Osiris (http://www.osiristx.com/) is looking at allergenic therapies. They are doing safety and efficacy studies now for the rejection issue. Cells in the cartilage are protected by their cell matrix, and there is no blood supply, so the body doesn't know that the cells are there in the first place.

Question 11: What is the ultimate potential for stem cells? Will we eventually be able to grow organs using stem cells? Is the area of medical research expanding exponentially?

The potential of stem cells is enormous. I like the idea of using stem cells to repair trauma or disease. But as far as growing organs, that is a distant goal. I think that one of the exciting prospects for the near future is understanding embryonic stem cells. Regarding exponential growth, it is difficult to talk about the medical field as a whole, because it is so broad. There are, however, elements in the medical field that are experiencing exponential growth.

Question 12: Is funding for stem cell research adequate?

There is a lot of funding for adult stem cells, whereas the funding is just starting for embryonic stem cells. It is a ramping up process. I think that funding is adequate. The NIH's research budget is quite large.

Question 13: What are your plans for the future? Do you have certain areas that you want to reach?

What I like about my job and research is facing new problems, and trying to develop novel methods to solve them. I hope that there will always be new problems to solve, but I hope that I don't know what it is. I like the idea of novelty, otherwise I would be bored. I don't want one Eureka moment. I want a series of progressions. For the next decade, I would like us to have the capability to have standardized tissue banks of stem cells that could be easily processed and that would be available for use. That alone would constitute a major advance.