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@PHDTHESIS{Herren:51565,
author = {Herren, Christian},
othercontributors = {Erli, Hans Josef Ludwig},
title = {{U}ntersuchungen zu verschiedenen {F}üllungskomponenten
eines porösen, keramischen {K}nochenersatzstoffes auf
{B}asis von {T}i{O}2 und {G}las und deren {A}uswirkungen auf
das {E}inwachsverhalten in vitales {K}nochengewebe},
address = {Aachen},
publisher = {Publikationsserver der RWTH Aachen University},
reportid = {RWTH-CONV-113846},
pages = {87 S. : Ill.},
year = {2010},
note = {Aachen, Techn. Hochsch., Diss., 2010},
abstract = {The substitution of bone tissue is necessary in case of
traumatic tissue infraction, after degenerative processes of
the skeletal system and finally in all endoprothetic
interventions. Respective in the research of open-porous
ceramics many experimental and clinical trials confirmed
that non-organic ceramics such as calcium phosphate,
bioactive glasses and glass-ceramic-hybrids have potential
applications in hard tissue replacement. In previous
in-vitro experiments we have shown that the TiO2/glass
composite Ecopore is well tolerated and the modification of
Ecopore with cell adhesion mediator fibronectin or bone
morphogentic protein-2 (BMP-2) led to enhanced spreading and
growth of human osteoblasts without cell damage. BMP-2 is a
morphogen and a growth factor with osteoinductive properties
– it has been studied to improve the integration of bone
replacement materials and thus to accelerate bone healing
[1,2]. In the present study we implanted Ecopore-cylinders
filled with BMP-2 and combined with Heparin/Collagen in a
rabbit bone defect model to find out whether bone ingrowth
could be further enhanced by this modification. We implanted
5 different modified Ecopore cylinders into critical size
defects of 10 medial rabbit femora and applied pulsed
polychrome sequence staging weekly. To overcome loss of
function due to chemical surface coupling, we filled the
pore system of Ecopore with heparinized collagen sponge and
loaded this secondary matrix with BMP-2 in 2 approaches.
After a period of 6 weeks we evaluated the resulting
bone/implant interface radiographically and histologically
to describe the bone apposition rate by fluorescence
microscopy and the ingrowth by energy-dispersive X-ray
spectroscopy analysis (EDX). Statistical significance was
estimated using Student’s t-test. During 6 weeks following
the implantation blinded histological analysis revealed all
implanted cylinders to be fully biocompatible and partially
ingrown. For quantification of the bone built-in we analyzed
the specimen by EDX: BMP-2 loaded Ecopore/collagen had
significantly higher bony ingrowth quantities in vivo, with
the heparinized modification yielding the highest value
(16.09 ± $3.51\%,$ p<0,005) compared to the non-heparinized
matrix (10.72 ± $4.07\%,$ p<0,05) and the BMP-2-free
controls (5.60 ± $1.47\%).$ Revealed by the fluorescence
microscopy these results were confirmed – BMP-2 loaded
Ecopore/collagen cylinders (22.325 ± 3.78 µm/week) had
higher bone apposition rate as the control group (18.01 ±
2.83 µ/week). We conclude that the TiO2/glass composite is
well tolerated without toxic reactions or inflammation
processes. In summary, etching and filling BMP-2 on a
heparinized collagen matrix can enhance bone tissue
ingrowth. Furthermore the Ecopore/collagen as the
BMP-2/Heparin-release system can be a new path for a greater
degree, e.g. the control of pore dimensions by
cross-linking, additional modification and the variation of
loading quantities of BMP-2.},
keywords = {Keramik (SWD) / Knochenersatz (SWD)},
cin = {533500-3 ; 931510},
ddc = {610},
cid = {$I:(DE-82)533500-3_20140620$},
typ = {PUB:(DE-HGF)11},
urn = {urn:nbn:de:hbz:82-opus-31649},
url = {https://publications.rwth-aachen.de/record/51565},
}
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