MAY 27 • 2021 | 43

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ubstantial tissue loss can be the
result from cancer, injury and
infection. Reconstructive surgery
attempts to mitigate the damage. Currently,
the clinical “gold standard” in the field of
reconstructive surgery is the autograft,
which entails harvesting tissue from one
part of the patient’s body and transferring it
to the damaged site.
For example, to reconstruct the lower jaw,
surgeons may harvest a portion of the fib-
ula bone, together with the soft tissue and
blood vessels around it, from the patient’s
leg. The soft tissue and blood vessels are
necessary for the bone to survive in its new
location.
As one might imagine, there are signifi-
cant disadvantages to taking a large chunk
out of one’s body, such as considerable pain
or all the usual complications associated
with a surgery at the donor site. Scientists
are therefore looking for alternatives to

tissue harvest and are moving toward tissue
engineering.
Although some progress has been made
in the field, there are still major challenges
to overcome in the search for tissue replace-
ments. The ultimate goal for the scientists is
de novo tissue generation. Instead of taking
tissues from one part of the body to implant
in another, new tissues for
implantation would be grown
in a lab.
That is where Professor
Shulamit Levenberg and her
team come in. In the faculty of
Biomedical Engineering at the
Technion, the focus of her tis-
sue regeneration lab has been
on the formation of complex blood vessel
networks in lab-grown tissues.
Recently, her team created vascularized
soft tissues for implantation using stem cells
derived from the dental pulp, that is the soft

tissue inside the tooth, together with capil-
lary forming (endothelial) cells. The addi-
tion of the dental pulp stem cells promoted
the generation of the blood vessels, eventu-
ally leading to enhanced tissue remodeling
and repair. The new methodology was then
used to repair a bone defect in rats, leading
to a complete recovery.
In a recent study conducted in
Levenberg’s lab, Dr. Idan Redenski and
his colleagues were able to put together
their own vascularized tissue
technology with biological
bone implants developed
at Columbia University by
Professor Gordana Vunjak-
Novakovic to create a de novo
tissue flap containing live bone
supported by vascularized soft
tissue. This took the concept of
implantable bone tissue to a whole different
level.
That, however, was only the first stage.
Having shown that a mixed tissue flap can
be grown, the team proceeded to use the
new methodology to repair a bone defect in
rats, using a two-step approach.
First, an engineered soft tissue flap was
implanted. Once it was integrated into the
body of the rat, the engineered flap was
exposed in a second surgery and used to
repair a bone defect, while being supported
by major blood vessels next to the defect
site. The decellularized bone was exposed
and inserted to correct the existing defect
while the engineered tissue flap supported
it.
The results were a complete success: The
soft tissue with the blood vessels supporting
and feeding the bone led to bridging of the
bony defect, with the rat’s cells growing in
and replenishing the implant. It was, in fact,
a complete recovery, better than anything
reconstructive surgery can achieve, and not
based patient tissue harvest.
Returning to the concept of a jaw
implant, one can hope that one day, based
on the methods developed by Professor
Levenberg, Dr. Redenski, and the rest of the
team, it will be possible for the patient to
receive a lab-grown bone perfectly match-
ing the shape of their face, surrounded by
lab-grown soft tissues based on their own
cells cultivated on 3-dimensional biomate-
rials. No major damage to other parts of the
patient’s body would be necessary.

From the Technion Israel Institute of Technology.

Professor
Shulamit
Levenberg

Growing Bone
in a Lab?

New advances from the Technion prove it’s possible.

HEALTH

A 3-dimensional
CT scan depicting
blood vessels
penetrating into
the embedded
bone, grown
within the
engineered flap.

Dr. Idan
Redenski