TY  - JOUR
A1  - Schneider, Tobias
A1  - Kohl, Benjamin
A1  - Sauter, Tilman
A1  - Kratz, Karl
A1  - Lendlein, Andreas
A1  - Ertel, Wolfgang
A1  - Schulze-Tanzil, Gundula
T1  - Influence of fiber orientation in electrospun polymer scaffolds on viability, adhesion and differentiation of articular chondrocytes
JF  - Clinical hemorheology and microcirculation : blood flow and vessels
N2  - Degradable polymers with a tailorable degradation rate might be promising candidate materials for biomaterial-based cartilage repair. In view of the poor intrinsic healing capability of cartilage, implantation of autologous chondrocytes seeded on a biocompatible slow degrading polymer might be an encouraging approach to improve cartilage repair in the future. This study was undertaken to test if the fiber orientation (random versus aligned) of two different degradable polymers and a polymer intended for long term applications could influence primary articular chondrocytes growth and ultrastructure.
 A degradable copoly(ether) esterurethane (PDC) was synthesized via co-condensation of poly(p-dioxanone) diol and poly(epsilon-caprolactone) diol using an aliphatic diisocyanate as linker. Poly(p-dioxanone) (PPDO) was applied as commercially available degradable polymer, while polyetherimide (PEI) was chosen as biomaterial enabling surface functionalization. The fibrous scaffolds of PDC and PPDO were obtained by electrospinning using 1,1,1,3,3,3 hexafluoro-2-propanol (HFP), while for PEI dimethyl acetamide (DMAc) was applied as solvent. Primary porcine articular chondrocytes were seeded at different cell densities on the fibrous polymer scaffolds and analyzed for viability (fluorescein diacetate/ethidiumbromide staining), for type II collagen synthesis (immunolabelling), ultrastructure and orientation on the fibers (SEM: scanning electron microscopy).
 Vital chondrocytes adhered on all electrospun scaffolds irrespective of random and aligned topologies. In addition, the chondrocytes produced the cartilage-specific type II collagen on all tested polymer topologies suggesting their differentiated functions. SEM revealed an almost flattened chondrocytes shape on scaffolds with random fiber orientation: whereby chondrocytes growth remained mainly restricted to the scaffold surface. On aligned fibers the chondrocytes exhibited a more spindle-shaped morphology with rougher cell surfaces but only a minority of the cells aligned according to the fibers. As a next step the reduction of the fiber diameter of electrospun scaffolds should be addressed as an important parameter to mimic cartilage ECM structure.
KW  - Chondrocytes
KW  - electrospinning
KW  - scaffold
KW  - differentiation
KW  - multiblock copolymer
Y1  - 2012
U6  - https://doi.org/10.3233/CH-2012-1608
SN  - 1386-0291
VL  - 52
IS  - 2-4
SP  - 325
EP  - 336
PB  - IOS Press
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Einarsson, Jon M.
A1  - Bahrke, Sven
A1  - Sigurdsson, Bjarni Thor
A1  - Ng, Chuen-How
A1  - Petersen, Petur Henry
A1  - Sigurjonsson, Olafur E.
A1  - Jonsson, Halldor
A1  - Gislason, Johannes
A1  - Thormodsson, Finnbogi R.
A1  - Peter, Martin G.
T1  - Partially acetylated chitooligosaccharides bind to YKL-40 and stimulate growth of human osteoarthritic chondrocytes
JF  - Biochemical and biophysical research communications
N2  - Recent evidences indicating that cellular kinase signaling cascades are triggered by oligomers of N-acetylglucosamine (ChOS) and that condrocytes of human osteoarthritic cartilage secrete the inflammation associated chitolectin YKL-40, prompted us to study the binding affinity of partially acetylated ChOS to YKL-40 and their effect on primary chondrocytes in culture. Extensive chitinase digestion and filtration of partially deacetylated chitin yielded a mixture of ChOS (Oligomin(TM)) and further ultrafiltration produced T-ChOS(TM), with substantially smaller fraction of the smallest sugars. YKL-40 binding affinity was determined for the different sized homologues, revealing micromolar affinities of the larger homologues to YKL-40. The response of osteoarthritic chondrocytes to Oligomin(TM) and T-ChOS(TM) was determined, revealing 2- to 3-fold increases in cell number. About 500 mu g/ml was needed for Oligomin(TM) and around five times lower concentration for T-ChOS(TM), higher concentrations abolished this effect for both products. Addition of chitotriose inhibited cellular responses mediated by larger oligosaccharides. These results, and the fact that the partially acetylated T-ChOS(TM) homologues should resist hydrolysis, point towards a new therapeutic concept for treating inflammatory joint diseases.
KW  - Cell culture
KW  - Chitolectin
KW  - Chitooligosaccharides
KW  - Chondrocytes
KW  - High affinity binding
KW  - Rheumatoid arthritis
KW  - YKL-40
Y1  - 2013
U6  - https://doi.org/10.1016/j.bbrc.2013.02.122
SN  - 0006-291X
VL  - 434
IS  - 2
SP  - 298
EP  - 304
PB  - Elsevier
CY  - San Diego
ER  -