Abstracts Posters SICOT-SOF meeting Gothenburg 2010 _2_

Poster
Topic: Biomaterials
Abstract number: 25023
BONE MORPHOGENETIC PROTEIN-2-HYDROGEL ENCAPSULATED
LIGAMENTUM FLAVUM CELLS FOR BONE REGENERATION
Chien-Hao CHEN, Chih-Hwa CHEN, Chih-Hsiang CHANG, Kun-Chung WANG,
Chung-Ming YU, Chun-I SU, Chak-Bor WONG, I-Chun WANG, Hsien-Tao LIU
Chang Gung Memorial Hospital - Keelung, Keelung (TAIWAN)
Osteogenesis of ligamentum flavum (LF) is a widely recognized pathophysiologic
factor in pathologic ossifications of spinal ligament. The potential for biomimetic
constructs with co-immobilized adhesion and bone morphogenetic protein-2 (BMP-2)
to induce osteoinduction and osteogenesis was demonstrated in our previous study.
LF cells could be a new source for bone regeneration in tissue engineering. For cell
isolation, LF tissue were obtained from spinal stenosis patients during spinal
decompression procedures and digested with medium containing collagenase. BMP-
2 was conjugated to polyethylene glycol by reacted with acrylate-PEG-Nhydroxysuccinimide
(Group 1). The soluble rhBMP-2 was incorporated poly (ethylene
glycol) diacrylate solution simultaneously for comparison (Group 2). LF cell-polymerphotoinitiator
suspension was subsequently loaded into disk-shaped molds with a 4mm
internal diameter, followed by photopolymerization with 365 nm UV light to gelate
the cell-polymer constructs. LF cell-photoinitiator suspension without rhBMP-2 was
as control group (Group 3). Hydrogel constructs were incubated in 24-well plates for
1, 7 and 14 days. Alkaline phosphatase (ALP) activity and immunohistochemical
assays were determined for the evidence of osteogenesis. Expressions of ALP,
osteoprotin and collagen type I of LF cells increased with cultured time in three
groups. Higher expressions of ALP, osteoprotin and collagen type I in group 1 than
those in group 2 at 7 and 14 day were observed. Free BMP-2 lost easily from
hydrogel. LF cells maintained higher osteogenesis in group 1 due to chemical bond
between polymer and BMP-2. Ligamentum flavum cells in photo-responsive hydrogel
encapsulated BMP-2 had shown potential in application of tissue engineering for
bone regeneration.
179