Hope for the Future: Injectible Tissue Engineering
By: Aya C. Chow
In the past, there has been
misleading claims about the ability to regrow cartilage for the relief of
arthritic joint pain. With the advancement of stem cell research however, there
may be realistic hope on the horizon.
Led by Jennifer Elisseeff, assistant
professor in the Department of Biomedical Engineering, researchers at John
Hopkins University have come a step closer to one day helping people who suffer
from cartilage degeneration. Though human testing is still years away, these scientists
have succeeded in growing stem cells from adult goats into
tissue that
resembles cartilage. This laboratory success allows researchers to proceed with
animal testing in
the fall.
In this process, stem cells are
placed in a fluid polymer material called photopolymerizing hydrogel. Hydrogel
provides the framework, nutrient carrying and waste disposing ability needed
for the stem cells to be coaxed into producing cartilage-like tissue or an
early form of bone, whichever is needed.
The beauty of this cartilage cell-laced hydrogel is that it can be
injected under the skin to the necessary place and then hardened into a solid
material framework that cartilage can grow into. Only by shining an ultraviolet
light or visible laser on hydrogel will it harden.
“If this technique
ultimately works the way we believe it will, doctors will have a new and
possibly more effective option for treating severe joint injuries,” Elisseeff
says. “This procedure would also help people avoid invasive
surgery.”1
The team aims to distribute and
direct the behavior of adult stem cells to restore damaged cartilage and bone
in human beings. Because cartilage does
not naturally regenerate, the success of this research for use in humans with
damaged or diseased cartilage could give millions hope.
Adult multipotent cells that can be
stimulated to create various types of musculoskeletal tissue are the focus of
this research, not human embryo or fetus stem cells. Use of adult stem cells
may be advantageous in another way. If, for example, patients can donate their
own stem cells before undergoing cartilage or bone repair surgery, they maybe
able to reduce infection and tissue rejection.
Elisseeff and her team thinks that
they’ve “come up with a clinically practical way to deliver the cells to the
site of an injury, where they can grow to replace injured bone or cartilage”
though some “difficulties still exist in smoothly joining new cells to the
recipient’s own tissue”.2 These problems and the fine-tuning of this
technique are being worked on
currently.
1
“Tissue Engineers Steering Stem Cells to Produce Bones, Cartilage”, Headlines
at Hopkins News Release, August 22, 2002.
2 op. cit.
Photo Credits: Keith Weller