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

