The effect of scaffold composition on the early structural characteristics of chondrocytes and expression of adhesion molecules.
Previously we demonstrated that chondrocyte ECM synthesis and mitotic activity was dependent on scaffold composition when cultured on uncoated PCL scaffolds (pPCL) or PCL composites containing hyaluronan (PCL/HA), chitosan (PCL/CS), fibrin (PCL/F), or collagen type I (PCL/COL1). We hypothesized that initial cell contact with these biomaterials results in ultrastructural changes and alters CD44 and integrin beta1 expression. The current study was designed to investigate the early ultrastructural responses of chondrocytes on these scaffolds and expression of CD44 and integrin beta1. A common observation 1 h after seeding was the abundance of cell processes. Different types of cell processes occurred in different areas of the same cell and on different cells within the same composite. Chondrocytes seeded onto PCL/CS had the greatest cell surface enhancement. PCL/HA promoted CD44 expression and almost spherical cells with a low degree of surface enhancement. PCL/COL1 enabled continuing expression of integrin beta1 and CD44. In contrast, cells in PCL/CS, PCL/F and pPCL promoted elliptic cells with a higher degree of surface enhancement and no prolonged CD44 and integrin beta1 expression. A strong variability of cell surface processes indicated either reparative or degenerative adaptation to the artificial environment. Interestingly, we found initial integrin beta1 expression in all composite scaffolds, but not in pPCL although this promoted strong adhesiveness as indicated by the formation of stress fibers. In conclusion, chondrocytes respond to biomaterials early after implantation by altering ultrastructural characteristics and expression of CD44 and integrin beta1.
Schagemann
Jan C
JC
Cartilage and Connective Tissue Research Laboratory, Department of Orthopedic Surgery, Mayo Clinic College of Medicine, Rochester, MN, USA. schagemann@cartilage-engineering.de
Kurz
Haymo
H
Casper
Michelle E
ME
Stone
James S
JS
Dadsetan
Mahrokh
M
Yu-Long
Sun
S
Mrosek
Eike H
EH
Fitzsimmons
James S
JS
O'Driscoll
Shawn W
SW
Reinholz
Gregory G
GG
D000199:Actins / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D048430:Cell Shape / Q000187:drug effects; D019902:Chondrocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D018960:Hyaluronan Receptors / Q000378:metabolism; D019012:Integrin beta1 / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010641:Phenotype; D011091:Polyesters / Q000494:pharmacology; D011817:Rabbits; D013499:Surface Properties / Q000187:drug effects; D054457:Tissue Scaffolds / Q000737:chemistry*
D000199:Actins; D015815:Cell Adhesion Molecules; D018960:Hyaluronan Receptors; D019012:Integrin beta1; D011091:Polyesters; C016240:polycaprolactone