- Bone marrow transplant is a common procedure to treat marrow
diseases such as aplastic anemia or immune destruction of the marrow.
- Pre-treatment of patient's marrow by radiation before a transplant
is associated with undesirable side effects.
- New lab designed bone marrow can be implanted beneath skin thus
eliminating need for host marrow irradiation.
bone designed by bioengineering professor Shyni Varghese and her
team at the UC San Diego Jacobs School of Engineering can be implanted under the skin where they have their
unique space to grow without competition from host marrow cells, eliminating
the need for the latter cells to be wiped out unnecessary.
Aim of the Research
The aim of this research was to make
bone marrow transplant
safe and free from
unwanted side effects for the patient.
‘Marrow produced by tissue engineering technology could successfully and safely treat bone marrow diseases caused due to immune damage and aplastic anemia, in the future.’
Usually, the patient's marrow is
pre-treated with irradiation prior
to a marrow transplant to destroy host cells and create space
for donor cells to grow. The pre-treatment is done to improve the chances of
success of bone marrow transplant but is associated with undesirable side
effects such as fatigue, nausea, vomiting, and infertility.
The engineered marrow used in the study
eliminated the need for such irradiation, making the transplant safer. "We've made an accessory bone that
can separately accommodate donor cells. This way, we can keep the host cells
and bypass irradiation," Varghese said. Details And Results of the Current Research
- The research team developed an
accessory bone similar to normal long bones in the body with an outer
porous hydrogel matrix composed of calcium phosphate minerals and an inner
- The engineered bone was filled with
donor stem cells and implanted beneath the skin of mice.
cells in the outer matrix developed into mature bone cells with
a vascular network. The inner marrow which held the donor stem cells grew
and differentiated into blood cells in the host.
weeks after the implant, the team found that the implanted marrow
contained a mixture of donor and host cells
confirming that donor stem cells and host cells traveled between the host
bloodstream and the implanted marrow via the vascular network in the bony
- The same mixture of donor and host
cells was found circulating in the bloodstream even 24 weeks after the procedure.
- The team of scientists also took
stem cells form the implanted marrow and infused them into mice whose
marrow had been destroyed by drugs or radiation.
- It was noted that the transplanted
stem cells also reached the bloodstream of the host.
"We did these experiments to show
that the bone marrow cells from the engineered bone tissues function similar to
native bone," said Yu-Ru
a research scientist in Varghese's lab and the study's first author.
of the Research
If further studies establish the safety
and efficacy of engineered bone marrow implants, it could lead to safer and
effective therapy for various bone marrow diseases. "In the future, our work could
contribute to improved therapies for bone marrow disease," said Shih.
However, bone marrow implants can only be
used in non-cancerous lesions of the marrow, since in case of malignancy, pre-treatment
radiation of marrow is essential to wipe out the cancer cells before a bone
marrow transplant can be done. Varghese
reiterates this and cautions
that these implants would be limited to patients with non-malignant bone marrow
diseases, where there are no cancerous cells that need to be eliminated.
The research team is using this model to produce
more bone marrow stem cells that may find applications in cell transplantations in the future.