Polyethylene glycol in spinal cord injury repair: a critical review

Journal of Experimental Pharmacology, 2018 · DOI: http://dx.doi.org/10.2147/JEP.S148944 · Published: January 1, 2018

Spinal Cord Injury Regenerative Medicine Biomedical

Simple Explanation

Polyethylene glycol (PEG) is a synthetic polymer with properties useful for treating spinal cord injury. Applying PEG directly to the injury site can repair cell membranes and promote axon regeneration. PEG can be linked to proteins and nanoparticles to improve their ability to cross the blood-brain barrier and reduce immune response. PEG can form hydrogels that deliver bioactive molecules and cells to modulate inflammation and support tissue regeneration. The properties of these hydrogels can be adjusted to optimize the delivery environment.

Study Duration

Not specified

Participants

Not specified

Evidence Level

Review

Key Findings

1
PEG, as a fusogen, can repair compromised neuronal membranes in SCI, potentially by dehydrating the cell membrane or reducing surface tension.
2
PEG hydrogels can act as supportive matrices in chronic SCI, promoting infiltration of glial cells and angiogenesis to promote axonal regrowth and some functional recovery.
3
PEGylation of nanoparticles reduces their uptake by cells, increasing their extracellular availability, which may be beneficial or detrimental depending on the application.

Research Summary

This review highlights the use of polyethylene glycol (PEG), a synthetic material known for its capacity to immediately repair physical damage and reduce local glial scar formation, and its applications in SCI. PEG can stimulate angiogenesis, isolate or reduce local glial scar invasion, promote and guide axonal regeneration, and restore synaptic connections with target tissue, hence stimulating injury repair. Despite having a simple structure, PEG has a flexibility in processing, which has made it useful in a number of applications for SCI. As we deepen our understanding of cell–material interface and the SCI lesion biology, we expect to see further utilization of PEG in treatment development.

Practical Implications

Acute SCI Treatment

Early and direct application of PEG to the severed spinal cord can mitigate neural damage and promote regenerative processes.

Chronic SCI Intervention

PEG can act as a supportive matrix in chronic injury settings, promoting glial cell infiltration, angiogenesis, and axonal regrowth, leading to functional recovery.

Targeted Drug Delivery

PEGylation can be tuned to optimize nanoparticle delivery to target cells in the CNS, either by enhancing or reducing cellular uptake.

Study Limitations

1
Potential for anti-PEG antibody development and accelerated clearance of PEGylated therapeutics.
2
Low-molecular-weight PEG may be deleterious to the release of encapsulated proteins.
3
Variations in study results based on the animal model and SCI severity.

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