Cell-cell interactions of human neural progenitor-derived astrocytes within a microstructured 3D-scaffold.

In the present in vitro study, the axon growth promoting effects of human neural progenitor-derived astrocytes (hNP-AC) were investigated in simple 2D- as well as in more complex 3D-culture systems. The interactions of the hNP-AC with migrating Schwann cells and fibroblasts were also studied. hNP-AC were found to promote extensive dorsal root ganglion axon regeneration in 2D cultures, being even greater than that observed on the positive control, laminin-coated substrate. Contact-mediated mechanisms and the release of substances into the medium both played a role in supporting axon regeneration. Following seeding onto 3D collagen scaffolds, hNP-AC also promoted significantly greater axon regeneration from DRG explants than was seen on non-seeded scaffolds. The highly orientated, porous microstructure of the scaffold also supported substantial intermixing of hNP-AC and migrating Schwann cells/fibroblasts from the DRG explant, cell populations that are normally mutually repulsive. This suggests that the topography of 3D scaffolds may not only influence cell–substrate interactions but also cell–cell interactions within the scaffold. This opens the possibility that the design of future scaffolds could be optimised to enhance cell integration as well as modulating complex cell–cell interactions.