Spinal Cord Injury Repair

Spinal cord injuries drastically decrease life expectancy and have countless effects on overall health.Less than three percent of people with complete spinal cord injury recover basic physical functions (“Dancing Molecules”). Researchers have been developing methods that repair spinal cord injuries in an attempt to increase both life expectancy and quality of life. Li et al. studied the effect of a nanofiber-hydrogel on spinal cord injuries. More specifically, they investigated if an injectable nanofiber-hydrogel composite (NHC) can provide mechanical support in a spinal cord injury and create an environment conducive to the permeation of endogenous cells through the injury by mimicking the mechanical properties and microarchitecture of soft tissue matrix. Adult female Sprague Dawley rats had their ninth thoracic spinal cord level contused and were then injected with either NHC, HA hydrogel-210 (H-210), HA hydrogel-80 (H-80), or saline at the epicenter of the injury (Li et al.). Li et al. found decreased spinal cord width in all rats, however those that received NHC injections had twice the average spinal cord width than rats that received saline injections. It was also found that rats injected with NHC had significantly more cells in the injury site overall compared to rats injected with H-210. These cells had a significantly greater ratio of pro-regenerative to pro-inflammatory macrophages compared to rats injected with H-80. NHC rats also had significantly more blood vessels than rats injected with saline and greater axon density than rats injected with saline or H-80 (Li et al.). Thus, research by Li et al. displayed increased regeneration in spinal cord injuries using NHC.

Álvarez et al. studied the effect of molecular motion in a nanofiber injection on spinal cord regeneration. Molecular motion in the supramolecular scaffold of nanoscale fibrils was increased by mutating the peptide sequence of amphipathic molecules in non-bioactive domains (Álvarez et al.). Álvarez et al. injected mice with a supramolecular polymer that consisted of one signal that induced axon regeneration and another signal that encourages blood vessel regrowth. Results showed that supramolecular polymers with increased molecular motion showed significantly more axon regrowth and functional recovery than saline in mice (Álvarez et al.). 

Álvarez et al. and Li et al. did not mention each other, likely because Li et al. focused on the composition of the injection and Álvarez et al. focused on the molecular motion of the injection, but future research may study if it is possible to increase molecular motion in the nanofiber-hydrogel used by Li et al. and how that increase affects regeneration in spinal cord injuries.

References

Álvarez, Z., et al. “Bioactive Scaffolds with Enhanced Supramolecular Motion Promote Recovery from Spinal Cord Injury.” Science, vol. 374, no. 6569, 11 Nov. 2021, pp. 848–856., https://doi.org/10.1126/science.abh3602. 

Li, Xiaowei, et al. “The Effect of a Nanofiber-Hydrogel Composite on Neural Tissue Repair and Regeneration in the Contused Spinal Cord.” Biomaterials, vol. 245, 16 Mar. 2020, p. 119978., https://doi.org/10.1016/j.biomaterials.2020.119978. 

Northwestern University. "‘Dancing molecules’ successfully repair severe spinal cord injuries: After single injection, paralyzed animals regained ability to walk within four weeks." ScienceDaily. ScienceDaily, 11 November 2021. <www.sciencedaily.com/releases/2021/11/211111153635.htm>.