One strategy for spinal cord injury repair is to make cellular bridges that support axon regeneration. However, the bridging cells often fail to integrate with host tissue and may lead to increased pain sensitivity. Recent work has tested bridging with two forms of progenitor-derived astrocyte. One type integrates, suppresses scar formation and promotes axon regeneration, whereas another very similar type, reported in Journal of Biology, does not support regeneration and increases pain sensitivity.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are