Stem cell research has potential, but faces challenges

Eng Hin Lee, MD, discussed the hurdles and possibilities of stem cell research at the BOA meeting.

Issue: November 2004

BOA - Manchester, England [icon] In his Presidential Guest Lecture at the British Orthopaedic Association Meeting in Manchester, England, Eng Hin Lee, MD, discussed the potential of stem cells in orthopedic research as well as the problems that face this area of science.

“We would [all] like to add more years to our lives, but also more life to our years,” said Lee, professor of orthopedic surgery and director of the division of graduate medical studies at National University of Singapore. “And this is something that we can talk about in terms of the potential of stem cells. We have been very good in the past 50 years or so doing things in terms of mechanical and biomechanical substitutes for bodies that are degenerating, but there is a trend now toward more biological methods of substituting for diseased parts, which brings me to the promise of stem cell research.”

Obtaining stem cells

Lee discussed the types of stem cells and issues associated with each type. Embryonic, pluripotent stem cells, while the most powerful in terms of potential to differentiate into different tissue types, are also the most controversial. “This stems from the fact that we are worried [about] what happens to the embryo or fetus; when does the embryo become human?” Lee said. “That is a question that very few people can answer. Even more difficult to answer is when does the soul enter the embryo? These are big dilemmas that we face if we deal with embryonic stem cells, and of course religious views vary.”

“Stem cells push us to learn so much in biology-in cell biology, in the biology of bone fracture, the biology of muscle healing.”
— Johnny Huard

One method of obtaining embryonic stem cells is from a fertilized embryo that is allowed to develop for five to six days, to the blastocyst stage, according to Lee. This is acceptable to some, Lee said, because the embryonic cells do not start to differentiate into types of tissues until 14 to 16 days.

Another, less controversial type of stem cell are adult stem cells, which can be derived from bone marrow or other adipose tissues. These cells are more directed, Lee said; they are multipotent rather than pluripotent.

Lee also discussed the various forms of stem cell legislation that exist around the world, from the prohibitive to the more liberal. Austria, for example, allows use of embryos only for in vitro fertilization, effectively banning stem cell research. The United States and Germany both allow stem cell lines derived before a certain point in the embryo’s development.

“Then there is the more liberal and pragmatic approach that allows embryos to be created for research purposes but under very strict legislation,” Lee said. “Countries like the United Kingdom, Israel and Singapore … and many others are now coming on and looking into legislation for stem cell research.”

Alternate methods

There are several methods that eliminate the ethical and legislative problems facing stem cell research, Lee said. A technique called nuclear reprogramming can derive stem cell lines from unfertilized eggs by transferring the nucleus from the somatic cell. “Another way would be parthenogenesis, where you can trick an unfertilized embryo into dividing,” he said. This method produces two sets of the same chromosomes, which may not be viable, according to Lee.

The potential uses of stem cells in orthopedics are many, Lee said. Studies have been done that indicate the potential to regenerate tissue in spinal cord injuries, as well as increasing mineral content in patients with osteoarthritis. Using stem cells at the insertion site for ACL reconstruction as well as for meniscal repair also could help the healing process. Lee said that there is still significant work to be done before these and other possibilities become realistic treatment options.

Johnny Huard, PhD, of the department of orthopedic surgery at the University of Pittsburgh, does research using post-natal muscle derived stem cells. “I think the application of stem cells for muscular dystrophy, for example, is far away because you have to inject the stem cells in all of those muscles,” he told Orthopedics Today. “But if you want to inject the stem cells to improve healing at a localized area, then that can be easier to apply.”

Huard believes that while embryonic stem cells may be effective, the less controversial muscle- and bone-derived cells can also work well. “If we heal a bone fracture by three weeks, maybe you can heal it by two-and-a-half weeks with embryonic stem cells, maybe they are better,” he said. “But the ethical problems that you’re going to have by using embryonic stem cells is not worth it.” He also pointed out that there are some advantages to post-natal derived stem cells, including the ability to do an autologous transplantation with cells derived from a patient’s own muscle or bone.

Both Lee and Huard agree that there is much that can be done and learned with the use of stem cells. “Stem cells push us to learn so much in biology,” Huard said, “in cell biology, in the biology of bone fracture, the biology of muscle healing. I think it will open a lot of new doors in the way that we think that we can improve the healing of that tissue.”

“I feel that there is a lot of potential in the use of stem cells to do translational research which can happen now or in the near future,” Lee said. “I think there is a lot of hope for us in the future.”

For more information:

Lee EH. The potential of stem cells in orthopaedic research. Presented at the British Orthopaedic Association Annual Congress. Sept. 15-17, 2004. Manchester, England.