Two teams of scientists have made significant advances in
potential technology to re-grow nerves after spinal cord
injuries. Both studies also highlight the formidable obstacles
that researchers in this field still face, even though one of
the techniques is likely to soon enter clinical trials in
paralyzed humans. “They’re both exciting pieces of work. We’re
getting closer,” says Jerry Silver, a neuroscientist at Case
Western Reserve University in Ohio who didn’t participate in
either study but is a prominent researcher in the area. The two
papers describe techniques to overcome nervous system features
that normally prevent spinal nerves from regenerating in
adulthood. In most animal species, basic central nervous system
pathways are almost entirely set before birth. As this process
is completed, genetic programs that produce some nerve-growth
factors (the term for special proteins that promote neuronal
growth) are switched off, and other programs are switched on to
suppress the growth of new nerves and prote