title: Substrate architecture and fluid-induced shear stress during chondrocyte seeding: role of alpha5beta1 integrin.
abstract: Chondrocyte behaviour has been shown previously to be influenced by the architecture of the substrate on which the cells are grown. Chondrocytes cultured on fully porous titanium alloy substrates showed greater spreading and more matrix accumulation when compared to cells grown on porous-coated substrates with solid bases. We hypothesized that these features developed because of differences in fluid-induced shear stresses due to substrate architecture and that integrins mediate these responses. Computational fluid dynamics analyses predicted that cells on fully porous substrates experience time-dependent shear stresses that differ from those experienced by cells on porous-coated substrates with solid bases where media flow-through is restricted. To validate this model, the seeding protocol was modulated to affect fluid flow and this affected cell spreading and matrix accumulation as predicted. Integrin blocking experiments revealed that alpha5beta1 integrins regulated cell shape under these two conditions and when cell spreading was prevented the increased accumulation of collagen and proteoglycans by chondrocytes seeded on fully porous substrates did not occur. Identifying the substrate-induced mechanical and molecular mechanisms that influence chondrocyte behaviour and tissue formation may ultimately lead to the formation of a tissue that more closely resembles natural articular cartilage.
authors.affiliation: CIHR-BioEngineering of Skeletal Tissues Team, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario, Canada.
authors.forename: Caroline G
authors.initials: CG
authors.lastname: Spiteri
authors.forename: Edmond W K
authors.initials: EW
authors.lastname: Young
authors.forename: Craig A
authors.initials: CA
authors.lastname: Simmons
authors.forename: Rita A
authors.initials: RA
authors.lastname: Kandel
authors.forename: Robert M
authors.initials: RM
authors.lastname: Pilliar
mesh_terms: D000497:Alloys; D000818:Animals; D002417:Cattle; D048430:Cell Shape; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000648:ultrastructure; D003094:Collagen / Q000502:physiology; D005109:Extracellular Matrix / Q000502:physiology; D039081:Integrin alpha5beta1 / Q000502:physiology*; D008855:Microscopy, Electron, Scanning; D008954:Models, Biological; D016062:Porosity; D011509:Proteoglycans / Q000502:physiology; D033081:Shear Strength; D014025:Titanium
chemical_list: D000497:Alloys; D039081:Integrin alpha5beta1; D011509:Proteoglycans; C031462:titanium alloy (TiAl6V4); D003094:Collagen; D014025:Titanium