Porous structures help boost integration of host tissue with
implants, study finds
NEW YORK – Results published today in FASEB (the journal of the
Federation of American Societies for Experimental Biology) by
researchers at Columbia University, including Jeremy Mao of the
Columbia College of Dental Medicine, demonstrate a novel way of using
porous structures as a drug-delivery vehicle that can help boost the
integration of host tissue with surgically implanted titanium.
Instead of being acted upon by the body as an impenetrable foreign
object, the synthetic bone replacement – currently being tested in
rabbits – features a porous material that allows for the delivery
of "microencapsulated bioactive cues" that speed up the growth of
host tissue at the site and allow for the growth of new bone.
A critical finding is that the drug dose needed for host tissue
integration by this controlled-release approach is about 1/10 of that
by the traditional technique of simple adsorption of the growth
factor.
http://www.eurekale
The approach could bring to orthopedics and dentistry a treatment
that has wrought much interest and success in the field of cardiology
with the development of drug-eluting stents, which take what is
ordinarily an inert tube, and infuse it with drugs to make the
placement of what is essentially a man-made, foreign object more
compatible with the patient's body, and at the same time, actively
promoting healing of injured tissue.
After just four weeks, the porous implants that Mao and his team are
using showed a 96 percent increase in bone-to-implant contact and a
50 percent increase in the growth of new bone over placebos.
How were such results achieved?
Since stem cells play a vital role in the growth of new bone, Mao and
his team have focused on impregnating the titanium implants with a
factor that "homes" the bodies' own regenerating cells to the
potential growth site to create and build on a platform for new bone.
The new approach may in the future obviate the need to harvest bone
from a non-injured site in the body for grafting into the site of
injury, as commonly performed now. This strategy, although often
effective, creates additional wounds. The work of Mao and his team
suggests that it should be possible to harnesses the body's natural
tissue regeneration capacity to recruit the right cells to the site
where new bone tissue is needed. Implants that naturally attract the
mesenchymal stem cells that can readily differentiate into bone, fat,
cartilage and other types of cells could be the way of the future,
Mao says. "In comparison with donor site morbidity and pain in
association with autologous tissue grafting, synthetic materials have
the advantage of ready and endless supply without any sacrifice of
donor tissue," he says.
The approach also overcomes a practical obstacle confronting many
orthopedic surgeons.
"This is a hybrid approach releasing biological cues from existing
orthopedic and dental implants to recruit the body's own stem cells.
It's unrealistic, at least from what we know now, to build a cell
culture room next to every operating room," Mao added. "Using these
types of porous implants doesn't require physicians to deliver stems
cells so much as it allows the patient's body to send its own cells
to the right place."
###
The research was supported by U.S. National Institutes of Health
grants DE015391 and EB02332 to Mao and his colleagues. Mao, D.D.S.,
Ph.D. is a dentist, a tissue engineer and professor at the Columbia
University College of Dental Medicine.
If you would like to interview Dr. Mao about this and other research
or would like a copy of the paper for further reading, please contact
Alex Lyda at (212) 305-0820.
Columbia University Medical Center provides international leadership
in pre-clinical and clinical research, in medical and health sciences
education, and in patient care. The medical center trains future
leaders and includes the dedicated work of many physicians,
scientists, nurses, dentists, and public health professionals at the
College of Physicians & Surgeons, the College of Dental Medicine, the
School of Nursing, the Mailman School of Public Health, the
biomedical departments of the Graduate School of Arts and Sciences,
and allied research centers and institutions. www.cumc.columbia.
Public release date: 30-Jan-2008
Contact: Alex Lyda
mal2133@columbia.
212-305-0820
Columbia University Medical Center
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http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
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