Patrick A Tresco — Page 2

PubMedDate not supplied

Composite articular cartilage engineered on a chondrocyte-seeded aliphatic polyurethane sponge.

To circumvent the reconstructive disadvantages inherent in resorbable polyglycolic acid (PGA)/polylactic acid (PLA) used in cartilage engineering, a nonresorbable, and nonreactive polyurethane sponge (Tecoflex sponge, TS) was studied as both a cell delivery device and as an internal support scaffolding. The in vitro viability and proliferation of porcine articular chondrocytes (PACs) in TS, and the in vivo generation of new articular cartilage and long-term resorption, were examined. The initial cell attachment rate was 40%, and cell density increased more than 5-fold after 12 days of culture in vitro. PAC-loaded TS blocks were implanted into nude mice, became opalescent, and resembled native cartilage at weeks 12 and 24 postimplantation. The mass and volume of newly formed cartilage were not significantly different at week 24 from samples harvested at week 6 or week 12. Safranin O-fast green staining revealed that the specimens from cell-loaded TS groups at week 12 and week 24 consisted of mature cartilage. Collagen typing revealed that type II collagen was present in all groups of tissue-engineered cartilage. In conclusion, the implantation of PAC-TS resulted in composite tissue-engineered articular cartilage with TS as an internal support. Long-term observation (24 weeks) of mass and volume showed no evidence of resorption.

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PubMedDate not supplied

Directional neurite outgrowth is enhanced by engineered meningeal cell-coated substrates.

After injury to the CNS, the anatomical organization of the tissue is disrupted, posing a barrier to the regeneration of axons. Meningeal cells, a central participant in the CNS tissue response to injury, migrate into the core of the wound site in an unorganized fashion and deposit a disorganized extracellular matrix (ECM) that produces a nonpermissive environment. Previous work in our laboratory has shown that the presentation of nanometer-scale topographic cues to these cells influences their morphological, cytoskeletal, and secreted ECM alignment. In the present study, we provided similar environmental cues to meningeal cells and examined the ability of the composite construct to influence dorsal root ganglion regeneration in vitro. When grown on control surfaces of meningeal cells lacking underlying topographic cues, there was no bias in neurite outgrowth. In contrast, when grown on monolayers of meningeal cells with underlying nanometer-scale topography, neurite outgrowth length was greater and was directed parallel to the underlying surface topography even though there exists an intervening meningeal cell layer. The observed outgrowth was significantly longer than on laminin-coated surfaces, which are considered to be the optimal substrata for promoting outgrowth of dorsal root ganglion neurons in culture. These results suggest that the nanometer-level surface finish of an implanted biomaterial may be used to organize the encapsulation tissue that accompanies the implantation of materials into the CNS. It furthermore suggests a simple approach for improving bridging materials for repair of nerve tracts or for affecting cellular organization at a device-tissue interface.

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