Repairing Spinal Cord

Scientists from the Salk Institute for Biological Studies have come across a molecule that can potentially aid in spinal cord repair. Reptiles, whales and snails have the ability to re–grow nerves after an injury, an ability humans are devoid of. The new research might help humans to mimic neuronal repair process that occurs naturally in lower animals.

A damaged nerve can regain functionality only when its long, signal–transmitting extensions known as ‘axons’ grow and establish new connections to other cells. Researchers had earlier learnt of protein p45, which helps to promote nerve regeneration by preventing the ‘axon sheath’ (known as myelin) from hindering the re–growth. However, humans, primates and some advanced vertebrates do not possess p45. Instead, they possess a different protein p75, which binds to the myelin when nerve damage occurs, thus, halting the growth in damaged nerves.

Scientists observed that two p75 proteins bind together to form a pair that latches onto the inhibitors released from damaged myelin. Later, by studying the configuration of the proteins in solutions using nuclear magnetic resonance (NMR) technology, researchers found that the growth–promoting p45 could actually disrupt the p75 pairing. The p45 protein binds to a specific area in p75 that is critical to the formation of the p75 pair, thus, limiting the amount of p75 pairs and consequently, letting the axons re–grow. The next step will be to ensure whether p45 can help regenerate the damaged human nerves that could aid thousands of people suffering from severe spinal cord injuries and paralysis.