RT..Transplanted Human Stem Cells Develop Into Broad Range of Tissues, Persist Over
/FROM PR NEWSWIRE PHILADELPHIA 800-523-4424/
TO NATIONAL AND MEDICAL EDITORS:
Transplanted Human Stem Cells Develop Into Broad Range of Tissues,
Persist Over a Year in Research at The Children's Hospital of Philadelphia
/ADVANCE FOR RELEASE AT 5 P.M. EST, TODAY/
/ADVANCE/ PHILADELPHIA, Oct. 30 /PRNewswire/ -- Adult human stem cells
taken from bone marrow have been induced to develop into a wide range of
normal tissues, including bone, cartilage, fat, tendon and muscle, when
transplanted into fetal sheep. The transplanted human cells have persisted in
various sheep tissues for over one year without rejection by the sheep's
immune system. The study offers promise that in the future these cells may be
useful for tissue repair or regeneration and for treatment of degenerative
diseases such as muscular dystrophy.
"Although a great deal of work remains to be done, these results suggest
great potential for the use of these cells in repair of damaged or
degenerating tissues, or for generation of new tissues, a process called
tissue engineering," said Alan W. Flake, M.D., director of The Children's
Institute for Surgical Science at The Children's Hospital of Philadelphia, who
led the study reported in the November issue of Nature Medicine. "One
possible future application might be the transplantation of normal stem cells
into a fetus diagnosed with muscular dystrophy. "These cells could then act
as a normal stem cell `reservoir' and replace the abnormal muscle with normal
muscle as it degenerates over time."
Stem cells are immature cells that develop into specialized cells
throughout the body, and those taken from embryos have the broadest potential
for giving rise to all the body's tissues. However, recent studies have shown
that cells with broad stem cell potential can be found in various adult
tissues as well, including the bone marrow and nervous system.
In the study at Children's Hospital, researchers harvested mesenchymal
stem cells (MSCs) from adult bone marrow. "The transplanted cells developed
in a site-specific fashion," said Dr. Flake. "They migrated to different
parts of the sheep's body and differentiated into types of tissue present at
each site."
Because the transplanted cells carried human DNA, it was possible to
identify them in different tissue. They became cells in skeletal muscle,
heart muscle, bone, cartilage, the thymus gland and stroma, which is
supporting structure for bone marrow. Furthermore, transplanted human MSCs
were found at the site of clipped tails in the sheep, suggesting that those
cells were involved in wound healing.
MSC transplants may have a future role in enhancing wound healing after an
injury or surgery. Additionally, said Dr. Flake, because MSCs also develop
into supporting cells in bone marrow, they might provide a more favorable
environment for the transplanted cells used in bone marrow transplants for
leukemias and other blood-based diseases. MSCs might also be used in gene
therapy, acting as vehicles to deliver beneficial genes to targeted tissues.
Although many institutions are currently investigating various types of
stem cells, this is the first study examining transplantation of human MSCs in
the fetal sheep model. In this current study, human MSCs were transplanted
into fetal sheep early in gestation, at either 65 days or 85 days, before and
after the brief window of time when their immune systems mature and become
active.
One surprise of the study, according to Dr. Flake, is the persistence of
these transplanted cells even in animals that were capable of rejecting
foreign cells at the time of transplantation. "This suggests that these cells
may have special immunologic properties that may allow transplantation between
individuals or even between species without rejection or the need for toxic
immunosuppressive drugs," added Dr. Flake.
Collaborating with Dr. Flake in the study was Kenneth W. Liechty, M.D., of
Children's Hospital. Other co-authors were from Children's Hospital and from
Osiris Th
Oct-30-2000 22:00 GMT
Source PRN PR NewsWire
Categories:
NWR/PA NWI/HEA NWI/MTC |
