title: Use of porous alginate sponges for substantial chondrocyte expansion and matrix production: effects of seeding density.
abstract: Autologous cell transplantation is a promising approach for cartilage repair, but the expansion of chondrocytes in a monolayer, a common approach to amplifying the cell number, inevitably leads to cell de-differentiation. To explore whether porous alginate sponges could be utilized for chondrocyte expansion and investigate the effects of seeding densities, the porcine chondrocytes were seeded to porous alginate sponges at low (5 x 10(5) cells per 40 sponges), medium (5 x 10(6) cells per 40 sponges), or high (2 x 10(7) cells per 40 sponges) density. After 4-week perfusion culture, all three groups resulted in chondrocyte proliferation, maintenance of chondrocytic gene (collagen II, Sox 9 and aggrecan) expression, and formation of cell clusters resembling cartilaginous tissues. The higher the seeding density, the higher the final cell density and GAGs production and, accordingly, the larger the cell clusters. Strikingly, the cumulative expansion ratios achieved by the low-density group ( approximately 150-fold) significantly exceeded those achieved by the medium (approximately 21-fold) and high (approximately 4.7-fold) density groups, as well as those achieved using other scaffolds. In conclusion, seeding chondrocytes to the alginate sponges at a low density, combined with perfusion culture, represents a drastic improvement in expanding autologous chondrocytes.
authors.affiliation: Department of Chemical Engineering and Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan 300.
authors.forename: Chi-Nan
authors.initials: CN
authors.lastname: Yen
authors.forename: Yu-Ru
authors.initials: YR
authors.lastname: Lin
authors.forename: Margaret Dah-Tsyr
authors.initials: MD
authors.lastname: Chang
authors.forename: Chun-Wen
authors.initials: CW
authors.lastname: Tien
authors.forename: Yu-Chih
authors.initials: YC
authors.lastname: Wu
authors.forename: Chun-Jen
authors.initials: CJ
authors.lastname: Liao
authors.forename: Yu-Chen
authors.initials: YC
authors.lastname: Hu
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000818:Animals; D002356:Cartilage / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000737:chemistry / Q000378:metabolism; D007150:Immunohistochemistry; D007596:Joints / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D023822:Tissue Engineering; D054457:Tissue Scaffolds
chemical_list: D000464:Alginates