Comparing natural hydrogels to self-assembling peptides in spinal cord injury treatment: a systematic review

<strong>Abstract</strong> <em><strong>Background:</strong></em><em> </em>In many cases, central nervous system (CNS) injury is unchanging due to the absence of neuronal regeneration and repair capabilities.<strong> </strong>In recent years, regenerative medicine, and especially hydrogels, have reached a significant amount of attention for their promising results for the treatment of spinal cord injury (SCI) currently considered permanent. Hydrogels are categorized based on their foundation: synthetic, natural, and combination. The objective of this study was to compare the properties and efficacy of commonly used hydrogels, like collagen, and other natural peptides with synthetic self-assembling peptide hydrogels in the treatment of SCI. <em><strong>Methods</strong></em><em>:</em><em> </em>Articles were searched in PubMed, Scopus, Web of Science, and Embase. All studies from 1985 until January 2020 were included in the primary search. Eligible articles were included based on the following criteria: administering hydrogels (both natural and synthetic) for SCI treatment, soley foucsing on spinal cord injury treatment, and published in a peer-reviewd journal. Data surronding xonal regeneration, revascularization, elasticity, drug delivery efficacy, and porosity were extracted. <em><strong>Results:</strong></em> A total of 24 articles were included for full-text review and data extraction. There were only one experimental study directly comparing Collagen I (as natural hydorgel) and PEG (as synthetic hydrogels) in an <em>in vitro </em>setting. The included study suggested PEG’s cell behavior is more expectable in the injury site, which makes it a more reliable scaffold. <em><strong>Conclusions:</strong></em> There is limited research comparing and evaluating both types of natural and self-assembling peptides (SAPs) in the same animal or <em>in vitro</em> study, despite its importance. Although we assume that the remodeling of natural scaffolds may lead to a stable hydrogel, there was not a definitive conclusion that synthetic hydrogels are more beneficial than natural hydrogels in neuronal regeneration.